DE102024207105A1 - Method for cleaning soiled surfaces with a cleaning robot - Google Patents

Abstract

A method for cleaning a soiled surface (3) using a cleaning robot (7, 7'),
wherein in a cleaning operation the cleaning robot (7, 7') travels over the soiled area (3) with a cleaning robot drive (30) and cleans the soiled area (3) with at least one brush (32a, 32b, 33a, 33b), in particular wherein the brush (32a, 32b, 33a, 33b) on the cleaning robot (7, 7') is motorically movable,
wherein the contaminated surface (3) extends with a lateral inclination α relative to a horizontal plane (HE), with α>25°, in particular α>35°,
is characterized by
that during cleaning operation the cleaning robot (7, 7') is connected to a crane (6) via a tethering rope (8, 8'),
wherein the tethering rope (8, 8') leads from a crane head (9, 9') at an outer end of a telescoping system (10) of the crane (6) to the cleaning robot (7, 7'),
and that the cleaning robot (7, 7') is held in a currently desired vertical position (GP) on the soiled surface (3) by the retaining rope (8, 8') during the cleaning operation, while the cleaning robot (7, 7') moves across the soiled surface (3) with its cleaning robot drive (30). The method according to the invention is cost-effective and flexibly applicable to steeply inclined soiled surfaces without any special requirements.

Description

The invention relates to a method for cleaning a soiled surface with a cleaning robot,
wherein in a cleaning operation the cleaning robot travels over the soiled area with a cleaning robot drive and cleans the soiled area with at least one brush, in particular wherein the brush on the cleaning robot is motor-driven,
wherein the contaminated surface runs with a lateral inclination α relative to a horizontal plane, with α>25°, in particular α>35°.

One such method became known, for example, through the internet publication “ HyCLEANER Photovoltaic Cleaning Robot: solarROBOT pro”, from hyCLEANER GmbH & Co. KG, Gronau, DE, see URL https://hycleaner.de/photovoltaik-reinigungsroboter/ downloaded on July 22, 2024 .

The generation of electricity from sunlight using photovoltaic modules, or the provision of heat using solar thermal modules, has become an important pillar of energy supply in many places. Photovoltaic modules and solar thermal modules are collectively referred to here as solar modules or solar panels.

Over time, however, solar panels become dirty, which impairs their performance. In particular, greasy and sooty dirt can accumulate, which is not removed, or only insufficiently removed, by rain. Therefore, solar panels are usually cleaned occasionally to restore their full performance.

Cleaning such soiled surfaces can be done manually by a worker, which is arduous for the worker and can also incur considerable costs.

For cleaning dirty solar modules, it is recommended from the above-mentioned internet publication “ HYCLEANER Photovoltaic Cleaning Robot: solarROBOT pro It has become known that a cleaning robot is being used. This robot travels along the soiled surfaces and cleans them using a brush system and water. The cleaning robot described is equipped with a tracked chassis. The cleaning robot can be controlled via a radio remote control.

Solar panels are often installed flat on the roofs of buildings, which may have a significant slope. It is also common practice to install solar panels at an angle to the horizontal, for example on stands, to achieve a favorable alignment of the solar panels with the sun's path, particularly depending on the latitude of the installation site.

Cleaning robots can usually be used on inclined solar panels with a side tilt of up to 25° from the horizontal plane without any additional equipment. However, with steeply inclined solar panels, such as those on steeply pitched roofs, there is a risk that the cleaning robot will slip. It would then be unable to perform its intended cleaning task and, in the worst case, could fall from the roof; the latter would endanger people passing by the building, and the cleaning robot would be destroyed.

The aforementioned online publication, "HyCLEANER Photovoltaic Cleaning Robot: solarROBOT pro," suggests equipping the cleaning robot with a side guide to enable it to operate on solar modules with an inclination of up to 45°. The cleaning robot can then be attached to the top edge of the solar modules using the side guide. Rollers integrated into the side guide roll along the top edge of the solar modules as the cleaning robot moves horizontally, thus preventing it from slipping. An illustration of the side guide is available online at [link to illustration]. URL https://hycleaner.de/wp-content/uploads/2023/05/Zubehoer-Seitenfuehrungscaled.webp accessed on 22.07.2024 to see.

A disadvantage of side guidance is that it requires a suitable, easily accessible edge on the solar modules for hooking, and is therefore only usable with certain types of solar modules. Furthermore, side guidance defines the cleaning robot's path of movement, and areas beyond this path are inaccessible. Side guidance is primarily suitable for ground-mounted solar installations.

A cleaning robot for solar modules, which is also equipped with a side guide, was featured in the internet publication " ROBSYS YTM Series” from Robsys Europe GmbH, Oer-Erkenschwick, DE, see URL https://rob-sys.de/ytm-serie/ downloaded on 22.7.2024 , has become well-known. Here, the cleaning robot is guided along the top and bottom edges of the solar modules.

From the subsequently published German patent application 10 2014 108 465.0 It has become known that a cleaning robot with a Pro The robot can be equipped with a propeller system, which uses a fluid flow from the surrounding environment to exert a force on the moving cleaning robot, thus preventing it from slipping. However, installing a propeller system is relatively complex.

From the internet publication “ SERBOT Swiss Innovations GEKKO Solar High-Tech Robot” by SERBOT AG, Stans, CH A cleaning robot for solar panels has become known, which is equipped with liftable suction cups that move along circumferential paths as its drive mechanism; see the URL. https://www.serbot.ch/en/solar-panels-cleaning/gekko-solar-robot Downloaded on July 26, 2024. The suction cups are intended to enable cleaning on sloping roofs with an incline of up to 45°. The cleaning robot's drive system with suction cups is structurally complex and consumes a lot of power during operation. Furthermore, the suction cups' adhesive properties may be impaired on heavily soiled surfaces or other unsuitable surfaces (e.g., edges on solar panel frames or gaps between solar panels).

Through the internet publication “ “Full PV yield for industrial buildings” by Klein Service GmbH, Jettingen-Scheppach, DE, see URL https://www.kleinpv.de/industrie.html, downloaded on July 26, 2024 It has become known that a brush assembly can be mounted at the front end of a blast crane to wet-clean solar panels on the roof of an industrial building. Such a blast crane is expensive to purchase. Furthermore, solar panels located on the roof surfaces facing away from the blast crane are often difficult to access.

Similar problems to those encountered when cleaning solar modules arise with other surfaces that need cleaning at a steep angle, such as glass and window surfaces, especially on building roofs.

Object of the invention

The object of the invention is to present a method for cleaning soiled surfaces, in particular solar modules, with a cleaning robot, which is cost-effective and flexible for use on highly inclined soiled surfaces without special requirements, and is particularly suitable for solar modules on roofs.

Description of the invention

This problem is solved according to the invention by a method of the type mentioned at the outset, which is characterized in that
that during cleaning operations the cleaning robot is connected to a crane via a tethering rope,
the holding rope leads from a crane head at an outer end of a telescopic system of the crane to the cleaning robot,
and that during cleaning operation, while the cleaning robot uses its cleaning robot drive to move across the soiled area, the cleaning robot is held in a currently desired vertical position on the soiled area by the retaining rope.

The invention provides for continuously securing the cleaning robot with a crane during cleaning operation to prevent it from slipping off the steeply inclined, soiled surface. Meanwhile, the cleaning robot can move along the soiled surface using its drive system, thereby performing the desired cleaning.

The crane features a telescopic system, usually with at least two telescopic booms. The crane head is located at the end of the outer boom, from which a tether cable extends to the cleaning robot. During any transport of the cleaning robot, which hangs freely through the air, the robot pulls on the tether cable with its entire weight.

As soon as the cleaning robot is placed on the steeply inclined, dirty surface and moves across it during cleaning, depending on the lateral incline, part of the robot's weight rests on the inclined surface ("normal force"), while part of its weight tries to push it downhill ("gravitational force"). This gravity force is completely counteracted by the tether cable, allowing the cleaning robot to maintain its (desired) vertical position. The gravity force thus creates a tensile force on the tether cable, which the cable (statically) absorbs.

The tethering rope remains under constant tension while the cleaning robot is positioned on the steeply inclined, dirty surface to prevent it from slipping. The tethering rope supports the portion of the robot's weight not borne by the support of the steeply inclined, dirty surface (notwithstanding any effects of friction). This applies regardless of whether the cleaning robot is moving or not.

When the cleaning robot moves across the soiled surface with its cleaning robot drive, especially when moving horizontally, the following occurs: The crane head typically guides the movement of the cleaning robot, at least partially, and preferably completely. The tether cable is typically held in a desired manner, particularly relative to the cleaning robot and/or relative to the inclined, soiled surface (more on this below). The tether cable keeps the cleaning robot in the desired vertical position at all times.

The (currently) desired vertical position of the cleaning robot is typically determined by programming.

When traversing horizontal cleaning paths, the desired vertical position remains constant throughout the traversal of each cleaning path; this is a common situation in cleaning operations. In the simplest case, the crane head then follows the horizontal movement of the cleaning robot completely synchronously ("one to one"), i.e., the relative position of the crane head to the cleaning robot is kept constant; however, it is also possible, for example, to change the distance between the crane head and the cleaning robot and to compensate for this change via the length of the tether cable between the crane head and the cleaning robot.

It is also possible to move the cleaning robot (at least in sections) uphill or downhill during cleaning operation, particularly using the robot's drive system. In this case, the desired vertical position can be gradually changed over time, for example, by gradually raising the robot to move higher up the soiled area. Furthermore, between cleaning horizontal paths, the cleaning robot can be moved uphill or downhill on the soiled area using the crane and tether cable (i.e., pulled up or lowered).

The inventive method of securing the cleaning robot with the crane and the tether cable is universally applicable and, in particular, does not require any specific design or geometry for the soiled surfaces to be cleaned or for associated solar modules, glass surfaces, or window surfaces. The soiled surfaces can also be located on building roofs without any problems. Furthermore, any cleaning robot can be used; it simply needs to be attachable to the tether cable, which can be easily achieved, for example, with one or more attachment points on the cleaning robot; such attachment points are often already present on conventional cleaning robots.

In many applications, a crane is already needed or desired to lower the cleaning robot onto the soiled surfaces to be cleaned and to remove it again after cleaning. Therefore, the crane is often already present on-site and thus does not incur any significant additional costs. Accordingly, within the scope of the invention, the crane and the tether cable can also be used to transport the cleaning robot through the air to lower it onto the soiled surface (e.g., on the roof of a building) or to remove it from the soiled surface.

The crane is typically mounted on a truck (crane truck or crane vehicle) or is a trailer for a motor vehicle. The truck or motor vehicle with trailer can then transport the crane and the cleaning robot to the work site, where they are deployed and moved to the next work site, and so on.

If desired, a teleoperation system can be used. The teleoperation system comprises a monitoring system that allows observation of the crane's surroundings, and in particular the cleaning robot, on the soiled area to be cleaned, from the crane's installation site. The monitoring system can, in particular, include one or more optical cameras on the crane, preferably with at least one optical camera installed on the crane head. The teleoperation system further comprises an operator station at a remote location (e.g., in a command center, typically several kilometers away from the crane's installation site). The information (images) from the monitoring system is transmitted to the operator station, where an operator can view this information (images). At the operator station, the operator can enter control commands for the crane and/or control commands for the cleaning robot, which are transmitted to the crane and/or the cleaning robot at the crane's installation site and executed there.

Preferred variants of the invention

A preferred variant of the method according to the invention provides that a vertical position of the crane head is higher than a vertical position of the cleaning robot.
and that the tether cable between the crane head and the cleaning robot is freely tensioned. This makes it easy to hold the cleaning robot. In particular, the tether cable is not deflected in the surrounding area, for example at the roof ridge or by special deflection devices. on the roof of the building. Because the mooring cable is freely tensioned, the risk of it becoming entangled (for example, on the edges of a solar panel) is reduced, and the risk of damage to the soiled surfaces (or associated solar panels) from a dragging mooring cable is eliminated. Typically, the vertical position of the crane head is also above all obstacles in the vicinity (e.g., roof ridges, chimneys, antennas, etc.).

A particularly preferred variant involves adjusting the position of the crane head and/or the length of the tether cable between the crane head and the cleaning robot as it moves across the soiled surface. This ensures the cleaning robot maintains the desired vertical position. This approach is simple and reliable. By adjusting the crane head and/or the length of the tether cable, the crane head can remain in a position favorable or suitable for slip prevention relative to the cleaning robot and the soiled surface, even as the cleaning robot moves across the soiled area. In particular, this allows the desired orientation of the tether cable to be maintained relative to the vertical and the plane of the soiled surface. Generally, the crane head follows the horizontal movement of the cleaning robot (at least partially), thereby ensuring the desired vertical position, especially through a suitable combination of the relative position of the crane head to the cleaning robot and the length of the tether cable. In a simple case, the crane head maintains a fixed distance from the cleaning robot (constant rope length L, corresponding to the fixed distance; note that the tethering rope is typically inclined away from the vertical); the vertical position of the crane head corresponds to the desired vertical position of the cleaning robot plus a predetermined height offset (the horizontal positions of the crane head and cleaning robot are typically offset from each other), and the crane head directly follows all horizontal movements of the cleaning robot. If the distance between the crane head and the cleaning robot needs to be changed (for example, to avoid obstacles), this can be compensated for by adjusting the length of the tethering rope (and usually by an additional positional correction of the crane head, mostly perpendicular to the direction of movement of the cleaning robot).

In a preferred further development of this variant, the crane is provided with a sensor system with which the current relative position of the cleaning robot to the crane is repeatedly determined by measurements.
The system uses the cleaning robot's relative position to the crane to control the tracking of the crane head's current position and/or the length of the tether cable. From each newly measured relative position of the cleaning robot, a new target position for the crane head and/or a new target length for the tether cable can be calculated, ensuring the desired vertical position of the cleaning robot is maintained. The robot then tracks this new target position and/or length. The sensor system allows the actual movements of the cleaning robot on the soiled surface to be determined directly during operation; no reading or knowledge of the cleaning robot's control commands is necessary. This significantly simplifies the interaction between the cleaning robot and the crane. This further development makes it possible to automate the tracking of the crane head's current position and/or the length of the tether cable, independent of the cleaning robot's control. In other words, the crane can then operate autonomously during tracking, which is particularly easy to set up. The cleaning robot can be controlled autonomously or manually by an operator (typically via radio). If desired, the relative orientation of the cleaning robot to the crane can also be repeatedly determined by measurements, and if desired, this can also be incorporated into the tracking of the current position of the crane head and/or the length of the mooring cable.

In a sub-variant of this further development, a motion model is used to predict at least one future relative position of the cleaning robot to the crane, and preferably also a future orientation of the cleaning robot to the crane. This prediction is then taken into account when tracking the current position of the crane head and/or the length of the tether cable. This allows the position of the crane head and/or the length of the tether cable to be adjusted more quickly to the values currently required by the cleaning robot (thus achieving a lower "effective latency" of the crane), and the tracking becomes more precise. According to the invention, this can be implemented using a Kalman filter/extended Kalman filter or particle filter (sequential Monte Carlo methods), and multiple motion hypotheses (how the cleaning robot will move) can be tracked simultaneously ("multimodal probability density functions").

• - momentane Position des Reinigungsroboters;
• - momentane Orientierung der Reinigungsroboters;
• - momentane Geschwindigkeit des Reinigungsroboters;
• - momentane Drehgeschwindigkeit des Reinigungsroboters;
• - kurz zurückliegende Positionen des Reinigungsroboters;
• - kurz zurückliegende Orientierungen des Reinigungsroboters;
• - kurz zurückliegende Geschwindigkeitswerte des Reinigungsroboters;
• - kurz zurückliegende Drehgeschwindigkeiten des Reinigungsroboters;

jeweils relativ zum Kran.The prediction or movement model can include one or more of the following pieces of information:

• - current position of the cleaning robot;
• - current orientation of the cleaning robot;
• - current speed of the cleaning robot;
• - current rotational speed of the cleaning robot;
• - recent positions of the cleaning robot;
• - recent orientations of the cleaning robot;
• - recent speed readings of the cleaning robot;
• - recent rotational speeds of the cleaning robot;

each relative to the crane.

A sub-variant that provides for is also advantageous.
that the crane's sensor system has one or more measuring sensors on the crane head, with which measurements are taken to determine the relative position of the cleaning robot to the crane head, and preferably also the relative orientation of the cleaning robot to the crane head,
and that, based on this specific relative position, and preferably also the specific relative orientation, of the cleaning robot to the crane head, and based on known instantaneous travel settings of the crane, in particular an instantaneous rotational position of a crane superstructure, instantaneous telescoping states of booms, instantaneous angles of boom joints, and/or a position of a cable extension, the relative position, and preferably also the relative orientation, of the cleaning robot to the crane is determined. This procedure has proven effective in practice and allows for a sufficiently accurate determination of the relative position of the cleaning robot to the crane (for cleaning soiled surfaces with a cleaning robot) in a simple and reliable manner. The crane (or its crane undercarriage/substructure) can be considered stationary during cleaning operations, as can the surfaces to be cleaned. The crane head can, in particular, include optical measuring sensors, especially optical cameras and/or a LiDAR measuring device. The cleaning robot can have measuring markers ("tags") that are detected by the optical measuring sensor. Alternatively, it is also possible to locate the cleaning robot and the crane (or crane head) via GPS.

A further advantage is a sub-variant which provides for,
that, as part of tracking the relative position of the crane head and/or the length of the mooring cable, target positions for the crane head are repeatedly determined,
and that the movements of the crane's actuators to achieve a specific target position of the crane head are calculated using methods of inverse kinematics. For calculating the actuator movements to reach the target positions, any number and arrangement of the crane's actuators (including rotary actuators, telescoping actuators, and cable actuators) can be used, applying the Denavit-Hartenberg convention. Accordingly, possible solutions ("actuator configurations") can be calculated that provide a required target position for the crane head. Preferably, taking into account current and upcoming obstacles along the crane head's trajectory, an actuator configuration is chosen that maximizes the distance to potential obstacles and simultaneously avoids mathematical poles of configurations (if any).

In the case of preferred further training of the above variant, it is planned that
that the tracking of the current position of the crane head and/or the length of the mooring cable is carried out in such a way that the mooring cable is held at least approximately in a tension plane,
wherein the tensioning plane is vertically oriented and perpendicular to the soiled surface. This ensures that the retaining rope essentially only prevents the cleaning robot from slipping, but does not pull the cleaning robot in a horizontal direction (especially in or against its direction of travel). Preferably, the retaining rope deviates from the tensioning plane by a maximum of 2°, more preferably by a maximum of 1°, and most preferably by a maximum of 0.5°.

In a further advantageous embodiment, the instantaneous position of the crane head and/or the length of the tether cable is tracked such that the tether cable is inclined, at least approximately, at an angle β from the vertical towards a plane of the soiled surface, with β ≥ 10.0°, preferably β ≥ 11.4°. This angle β ensures that, despite the holding effect of the tether cable, a certain proportion of the cleaning robot's weight force still acts perpendicular to the plane of the soiled surface, meaning the cleaning robot continues to exert pressure on the soiled area. This improves the cleaning function of the at least one brush and enhances the effectiveness of the cleaning robot's drive system. on the soiled surface. With a pull angle of β ≥ 10°, it is ensured that, in the limiting case of a lateral inclination of α = 25°, at least 1/3 of the normal force of the cleaning robot (without crane) acting perpendicularly into the inclined soiled surface is not counteracted by the crane. With a pull angle of β ≥ 11.4°, it is ensured that, in the case of a lateral inclination of α = 35°, at least 1/3 of the normal force of the cleaning robot (without crane) acting perpendicularly into the inclined soiled surface is not counteracted by the crane.

A preferred option is a sub-variant of this training program in which
β ≥ arctan [3/2*tan(α)] - α is chosen.
With this angle of pull β, it is ensured that, under the holding effect of the crane, a cleaning robot still presses on the soiled surface with at least 1/3 of its normal force prevailing at the angle of inclination α without the crane.

In another preferred further development, the current position of the crane head and/or the length of the mooring cable is tracked in such a way that the telescoping system of the crane and the mooring cable are guided around known obstacles near the contaminated area.
In particular, a detection sensor system mounted on the crane identifies known obstacles through measurements. This prevents damage to the crane or the obstacles, and the mooring cable does not become entangled. Preferably, the obstacles are automatically taken into account during automated tracking of the crane head and/or the length of the mooring cable. If desired, a user can also manually (pre-program) known obstacles, such as chimneys or antennas on the roof of a building with solar panels to be cleaned, so that these are automatically avoided during automated tracking.

The crane can typically maintain the desired vertical position of the cleaning robot in various ways (with different actuator configurations), particularly with different crane head heights and different tether cable lengths, and, if necessary, with different pull angles. The corresponding degrees of freedom can be used to circumvent known obstacles.

A particularly preferred development involves automating the tracking of the crane head's current position and/or the length of the mooring cable via an electronic control unit on the crane. This makes tracking faster and more reliable (compared to manual tracking).

In a preferred sub-variant of this further development, an initial vertical position of the cleaning robot is determined and stored in the electronic control unit at the start of the cleaning operation. During subsequent cleaning operations, the electronic control unit maintains this initial vertical position as the desired vertical position while the cleaning robot traverses at least one horizontal cleaning path on the soiled surface. This approach has proven effective in practice and is particularly simple. Typically, at the start of the cleaning operation (during initiation), a relative position and, if necessary, a relative orientation of the cleaning robot to the crane (or crane head) is determined and taken into account for subsequent tracking, particularly to maintain this relative position and/or orientation and/or any associated alignment of the tether cable relative to the soiled surface. In the latter case, the alignment of the tether cable during initiation should then correspond to the desired alignment of the tether cable during cleaning operation (e.g., regarding the arrangement of the tether cable in the tension plane and/or the setting of the tension angle β).

A preferred option is a variant in which the cleaning robot, during cleaning operation, moves at least section by section along a horizontal direction on the soiled surface. Such movement of the cleaning robot is particularly easy to control and can be secured against slipping on a steeply inclined, soiled surface using the crane and its tether cable.

Advantageously, another variant provides that the attachment point of the tether on the cleaning robot is offset from the robot's central plane towards an uphill side. This ensures that a cleaning robot suspended from the tether would tip over with its lower end onto the soiled surface. This can help to increase the force with which the cleaning robot presses against the soiled area.

A variant that provides for is still advantageous.
that the cleaning robot continues to clean the soiled area with a cleaning fluid during cleaning operation,
and that the cleaning fluid is supplied via a supply line that runs from the crane, over the crane head, to the cleaning robot, in particular In this system, a storage tank and a pump for the cleaning fluid are mounted on the crane. The pump draws the cleaning fluid from the storage tank through the supply line to the cleaning robot. The cleaning fluid improves the cleaning effect on the soiled surface. It can contain a surfactant and/or a solvent, such as alcohol or isopropanol. Routing the supply line over the crane (typically held and guided by a tether cable) ensures a simple supply of cleaning fluid to the cleaning robot. This eliminates the need for alternative routing of the supply line, such as across the roof on solar panels. By mounting the storage tank and pump on the crane, the crane and cleaning robot system operates autonomously, which is advantageous, for example, when cleaning remote open-field installations where a local water supply is unavailable. If desired, the storage tank and pump can also be located independently (separately) from the crane, for example, on another vehicle or trailer.

• - einen Reinigungsroboter, der einen Reinigungsroboter-Antrieb aufweist, mit dem der Reinigungsroboter eine verschmutzte Fläche abfahren kann, und der wenigstens eine Bürste aufweist, mit der die verschmutzte Fläche beim Abfahren gereinigt werden kann, insbesondere wobei die Bürste am Reinigungsroboter motorisch beweglich ist,
• - einen Kran, umfassend ein Teleskopiersystem, einen Krankopf an einem äußeren Ende des Teleskopiersystems, und eine elektronische Steuereinrichtung, wobei der Reinigungsroboter über ein Halteseil mit dem Kran verbunden ist, wobei das Halteseil vom Krankopf zum Reinigungsroboter führt,

und wobei die elektronische Steuereinrichtung dazu eingerichtet ist, während eines Reinigungsbetriebs, währenddessen der Reinigungsroboter auf der verschmutzten Fläche mit seinem Reinigungsroboter-Antrieb verfährt, den Reinigungsroboter mit dem Halteseil automatisch auf einer programmierten, momentan gewünschten vertikalen Position auf der verschmutzten Fläche zu halten. Mit dem erfindungsgemäßen System ist es möglich, kostengünstig und flexibel praktisch beliebige verschmutzte Flächen mit großer Seitenneigung α gegen die horizontale Ebene, insbesondere mit α>25°, oder sogar α>35°, zu reinigen. Über den Kran kann der Reinigungsroboter gegen ein Abrutschen hangabwärts gesichert und stabilisiert werden, so dass der Reinigungsroboter auch bei dieser großen Seitenneigung seine Reinigungsfunktion ausüben kann. Die zu reinigende Fläche oder zugehörige Solarmodule müssen keine besonderen Voraussetzungen erfüllen, um mit dem erfindungsgemäßen System gereinigt werden zu können.The present invention also includes a system for cleaning soiled surfaces,
in particular wherein the system is configured to carry out a method according to the invention described above,
the system includes

• - a cleaning robot which has a cleaning robot drive with which the cleaning robot can travel across a soiled surface, and which has at least one brush with which the soiled surface can be cleaned while traveling across it, in particular wherein the brush on the cleaning robot is motor-driven,
• - a crane comprising a telescoping system, a crane head at an outer end of the telescoping system, and an electronic control device, wherein the cleaning robot is connected to the crane via a tethering rope, the tethering rope extending from the crane head to the cleaning robot,

and wherein the electronic control unit is configured to automatically hold the cleaning robot in a programmed, currently desired vertical position on the soiled surface by means of the tether cable during a cleaning operation, while the cleaning robot is moving across the soiled surface with its cleaning robot drive. With the system according to the invention, it is possible to clean virtually any soiled surface with a large lateral inclination α to the horizontal plane, in particular with α > 25°, or even α > 35°, cost-effectively and flexibly. The cleaning robot can be secured and stabilized against slipping downhill by means of the crane, so that the cleaning robot can perform its cleaning function even at this large lateral inclination. The surface to be cleaned or associated solar modules do not have to meet any special requirements in order to be cleaned with the system according to the invention.

An advantageous further development of this embodiment is characterized by the electronic control unit being configured to adjust the instantaneous position of the crane head and/or the length of the tether cable between the crane head and the cleaning robot during cleaning operation, while the cleaning robot is moving across the soiled surface with its drive system, in order to maintain the cleaning robot in the currently desired vertical position. By adjusting the crane head and/or the length of the tether cable, the crane head can remain in a position favorable or suitable for slip prevention relative to the cleaning robot and the soiled surface, even as the cleaning robot moves across the soiled surface. In particular, this allows the desired orientation of the tether cable to be maintained relative to the vertical and relative to the plane of the soiled surface.

In a preferred embodiment, the cleaning robot drive comprises a tracked chassis with at least two tracks. Tracks allow the driving force of the cleaning robot to be transmitted very reliably to the soiled surface or substrate. Furthermore, the tracked chassis enables the cleaning robot to rotate in confined spaces, which is advantageous for repositioning the cleaning robot (especially for changing the horizontal cleaning path) and for completely cleaning the soiled area.

The scope of the present invention also includes the use of a system according to the invention, described above, for cleaning soiled surfaces,
The soiled surfaces run at a lateral inclination α relative to a horizontal plane, with α > 25°, and in particular α > 35°. The crane allows the cleaning robot to be reliably held even on such steeply inclined soiled surfaces, enabling it to perform its cleaning function. The system can be used flexibly on virtually any soiled surface.

A preferred embodiment of the invention provides that the soiled surfaces are formed by solar panels, in particular photovoltaic panels. Solar panels lose power when soiled, which can be easily restored by using the system for cleaning. Alternatively, other soiled surfaces, in particular glass surfaces and window surfaces, can also be cleaned within the scope of the invention.

A variant of the use according to the invention is also preferred in which the contaminated surfaces are arranged on the roof of a building.

On the roof of a building, which is difficult for workers to access, it is particularly challenging to use a cleaning robot on steeply inclined surfaces. Furthermore, a crane can be used to easily and conveniently lift the cleaning robot onto and off the roof. The crane can also be used to reposition the cleaning robot (especially for vertical repositioning and/or moving between locations on the roof that would be inaccessible to the robot's drive system). Alternatively, the soiled areas can be arranged differently, particularly on stands mounted on the ground, for example, in the case of soiled areas formed by solar panels in a ground-mounted solar array.

Further advantages of the invention will become apparent from the description and the drawing. Likewise, the features mentioned above and those described in more detail below can each be used individually or in any combination according to the invention. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples for illustrating the invention.

Detailed description of the invention and drawing

• 1 Figure 1 shows an exemplary embodiment of a system according to the invention for cleaning soiled surfaces in a schematic side view, on the gable end of the associated building;
• 2 shows a section of the system of 1 during an exemplary variant of a method according to the invention for cleaning soiled surfaces, in a schematic top view of the associated building;
• 3 shows the section of the system from 2 , in a schematic side view, on the long side of the associated building;
• 4 shows a section of the system of 1 during an exemplary further variant of a method according to the invention for cleaning soiled surfaces, in a schematic view of the associated building, whereby an obstacle is bypassed;
• 5 shows the section of the system from 4 , in a schematic view of the gable end of the associated building.
• 6 shows a schematic side view of an exemplary cleaning robot for the invention;
• 7 shows the cleaning robot from 6 , in schematic frontal view;
• 8 shows a schematic side view of a section of the system of 1 , including the crane head and the cleaning robot;
• 9 Illustrated in a schematic side view are the forces acting on the cleaning robot during the method according to the invention.

The 1 Figure 1 illustrates a schematic side view (of the gable end of building 1) of a system 2 according to the invention for cleaning soiled surfaces 3 in an exemplary embodiment in a typical application situation. In the illustrated example, the soiled surfaces 3 are formed by solar panels (also called solar modules) 4, which are located on the roof 5 of building 1.

System 2 comprises a crane 6 and a cleaning robot 7, which is connected to the crane 6 via a tethering rope 8.

The cleaning robot 7 is designed to clean the soiled surfaces 3 with at least one brush, and to move across the soiled surfaces 3 with a cleaning robot drive (not explained in more detail in 1 , cf. but 6 and 7 (to this).

However, the roof 5 of building 1 is relatively steep, and the solar modules 4 lie flat on the roof 5. Accordingly, the soiled surfaces 3 have a comparatively large lateral inclination α relative to the horizontal plane HE (shown as an example for the right-hand soiled surface 3, on which the cleaning robot 7 is positioned). In the illustrated example, the lateral inclination α is approximately 48°. Due to the strong sides Due to the incline α of the soiled area 3, the cleaning robot 7 would, without further measures, slip downhill and fall from the roof 5.

The invention provides that the cleaning robot 7 is secured at a desired vertical position (vertical height) GP by means of the crane 6. For this purpose, the tethering cable 8 runs from a crane head 9 to the cleaning robot 7. The crane head 9 is formed at the outer end of a telescopic system 10 of the crane 6 and is movable in all three spatial directions relative to the crane 6 or its crane undercarriage/substructure 11 by means of the telescopic system 10. The crane head 9 is located at a vertical position (vertical height) VKK. VKK can, for example, be fixed at the underside of the crane head 9 where the tethering cable 8 meets the crane head 9.

During cleaning operations, the cleaning robot 7 is held in place by the tether cable 8. The cleaning robot 7 pulls on the crane head 9 with part of its weight, and consequently the tether cable 8 is under a certain tension.

The cleaning robot 7 is located at a vertical position VRR; note that VRR is significantly below VKK. VRR can be defined, for example, at the attachment point (point of attack) of the tether cable 8 on the cleaning robot 7. The vertical position VRR of the cleaning robot 7 is determined by the position of the crane head 9 and the length L of the tensioned tether cable 8 between the crane head 9 and the cleaning robot 7 (subject to the boundary condition of the shape of the soiled surface 3). In particular, the cleaning robot 7 cannot slip downhill on the soiled surface 3, as it is prevented from doing so by the tether cable 8. By appropriately adjusting the position of the crane head 9 and the length L of the tether cable 8, the vertical position VRR of the cleaning robot 7 can be adjusted to correspond to a desired vertical position GP.

The tether 8 is inclined at an angle β to the vertical direction (also called vertical) V towards the plane FE of the soiled surface 3. In the illustrated example, the angle β is approximately 15°. This angle β ensures that the cleaning robot 7 still exerts some pressure on the soiled surface 3 with its weight. This guarantees effective cleaning by the cleaning robot 7, particularly by its at least one brush.

During cleaning operation, the cleaning robot 7 typically follows a horizontal cleaning path on the roof 5 or on the soiled area 3, i.e., in 1 with a direction of travel perpendicular to the plane of the drawing. During this movement of the cleaning robot 7, the crane head 9 is guided (more on this in the 2 , 3 , 4 until 5 ).

The three-dimensional mobility of the crane head 9 is provided by the telescopic system 10 of the crane 6. In the illustrated embodiment, the crane 6 has a crane superstructure 12, which is rotatable about a vertical first axis of rotation DA1 relative to a crane undercarriage 11 (which is stationary when the crane 6 is erected). A telescopic first crane boom 13 (also called the main crane boom) is arranged on the crane superstructure 12. The first crane boom 13 can be pivoted about a horizontal second axis of rotation DA2 by means of a pivot joint 14. Furthermore, the length of the first crane boom 13 can be adjusted in two telescopic stages. A second crane boom 15 (also called the auxiliary crane boom) is attached to the first crane boom 13 via a further pivot joint 16 and can be pivoted about a further horizontal axis of rotation DA3 relative to the first crane boom 13. Furthermore, the second crane boom 15 is adjustable in length by means of two telescopic sections. The crane head 9 is formed at the outer end of the second crane boom 15. The length L of the extended mooring cable 8 is also usually adjustable, typically by means of a winch (not shown in detail in [reference]). 1 , cf. But 8 All described movements (degrees of freedom) of the telescoping system 10 can be controlled via associated actuators (typically electric or hydraulic actuators). The current adjustment setting of all actuators of the crane 6 or its telescoping system 10 is also referred to as the "actuator configuration".

The current adjustment setting of the telescopic system 10 determines the current position of the crane head 9 relative to the crane 6 or its stationary crane undercarriage 11. It should be noted that a specific position of the crane head 9 (relative to the crane undercarriage), also called the target position, can typically be achieved with a variety of different actuator configurations. The adjustment setting of the telescopic system 10 can be controlled via an electronic control unit 17, and in particular, can also be controlled automatically. Methods of inverse kinematics can be applied to find suitable adjustment settings for a desired target position of the crane head 9.

In the configuration shown, the crane 6 is mounted on a crane truck 18, which allows the crane 6 to be transported between different locations. At each location, the crane truck 18 is supported by a support system. (not shown in detail) secured against tipping. In the illustrated design, the crane 6 also includes a storage vessel 20 for a cleaning fluid 21, for example a mixture of water and a surfactant, and a pump 22 for the cleaning fluid 21. This allows the cleaning fluid 21 to be supplied via a supply line (not shown in detail). 1 , but see 8 (For this purpose) the material is transported from the crane undercarriage 11 via the booms 13 and 15 and the crane head 9 to the cleaning robot 7 to assist in cleaning the soiled areas. If desired, the supply line can also include a data transmission line, via which, in particular, control commands can be transmitted from the control unit 17 of the crane 6 to the cleaning robot 7 and/or reports can be sent from the cleaning robot 7 to the electronic control unit 17 of the crane 6.

If desired, a heating device for the cleaning fluid 21 can also be provided at crane 6. Additionally, if desired, a water softener or a demineralization plant (e.g., a reverse osmosis system) can be installed at crane 6 to produce softened or demineralized water on-site for cleaning the contaminated surfaces. Furthermore, crane 6 typically has its own power generator to operate the actuators and other equipment on crane 6, particularly for autonomous operation (each not shown in detail).

The 2 overlooked on the roof 5 and 3 Figure 5, in a side view of the long side of the roof, illustrates an exemplary process for cleaning the soiled area 3 with the moving cleaning robot 7. Note that the crane 6 is only partially shown for the sake of simplicity.

Each solid line shows a first situation in which the cleaning robot 7 is placed on the roof 5 of building 1 or on the soiled area 3 of the solar modules 4, and secured against slipping with the taut retaining rope 8 (as in 1 illustrated).

In the 2 and 3 It is clearly evident that the retaining cable 8 runs in a tension plane SE, which is vertically oriented and continues perpendicular to the contaminated surface 3 (or the associated plane FE, see 1 ) stands.

The situation shown with solid lines can be used to initiate further control of crane 6.

The cleaning robot 7 is now to be moved horizontally, cf. direction of travel 23, to clean the soiled area 3. For this purpose, the cleaning robot 7 activates its cleaning robot drive. To enable the cleaning robot 7 to move horizontally and to prevent it from slipping off the roof 5 (i.e., to maintain the desired vertical position GP of the cleaning robot 7), the crane head 9 is moved in the illustrated example. In the illustrated example, the crane head 9 performs the same translational movement as the cleaning robot 7 by moving along direction of travel 24. Direction of travel 24 is parallel to direction of travel 23, and the travel speed of the crane head 9 corresponds to the travel speed of the cleaning robot 7.

The crane head 9 is automatically tracked by the crane 6's electronic control unit. To enable the electronic control unit to determine which movement of the crane head 9 it needs to initiate to follow the cleaning robot 7, measuring sensors are preferably arranged on the crane head 9. These measuring sensors monitor the relative position of the cleaning robot 7 to the crane head 9 with high temporal and spatial resolution (measuring sensors in 2 and 3 not shown in detail, but see below. 8 (for this purpose). If the current relative position of the cleaning robot 7 deviates from a target relative position, the crane head is moved so that the current relative position approaches the target relative position again. In the example shown, the target relative position is the relative position that was determined (measured) during initiation.

Typically, the relative position of the cleaning robot is measured at least 100 times per second and compared with the target relative position. Based on the comparison results, control commands are issued to the actuators of the crane 6's telecopying system. This ensures that the cleaning robot 7 only minimally precedes the crane head 9, specifically so little that the tether cable 8 is not noticeably swung out of the span SE (typically by a maximum of 2°, usually a maximum of 1°, and often a maximum of 0.5°). The tracking of the crane head 9 (and, if applicable, the length of the tether cable 8) is so fast that the tether cable 8 does not yet noticeably impair the cleaning robot 7's horizontal movement. If desired, future relative positions of the cleaning robot 7 can be predicted using a motion model to achieve a lower effective latency of the crane 6.

The dotted line shows a situation that has been reached on the soiled area 3 after the horizontal procedure of the cleaning robot 7'. The cleaning robot 7' remains in the desired vertical position GP, which has remained constant throughout the cleaning robot 7's journey.

Note that, in general, a multitude of combinations of relative positions of the crane head 9 to the cleaning robot 7 and lengths of the tether cable 8 are possible to hold the cleaning robot 7 in a desired vertical position GP. If a specific angle of pull is to be maintained, the possible positions of the crane head 9 lie on a straight line; if the angle of pull is variable, the possible relative positions of the crane head 9 lie in the span plane SE (in each case assuming that the tether cable 8 is to remain parallel to the span plane SE so as not to impede the movements of the cleaning robot 7 with its drive mechanism).

The 4 overlooked on roof 5 and the 5 A side view of the gable end of building 1 illustrates, in a further example, how the cleaning robot 7 moves across a dirty surface 3, formed by solar panels 4 on the roof 5, while being held by the crane 6. For the sake of simplicity, the crane 6 is again only partially shown.

The initial situation is shown again with solid lines. The cleaning robot 7 is to be moved horizontally 23 across the soiled surface 3 to clean it, and is to be secured against slipping by the crane 6.

In the example shown, there is an obstacle 25 on the roof 5, namely a chimney 26. If the crane head 9 were simply moved parallel to the cleaning robot 7 from the initial position, the second crane boom 15 of the crane 6 would collide with the chimney 26.

The electronic control unit of crane 6 receives measurement information from a detection sensor system 27, which in this case has sensors on the crane head 9. The detection sensor system 27 identifies the chimney 26 as an obstacle 25, and this obstacle can then be taken into account by the control unit when controlling the actuators of crane 6, as the crane head 9 and, in this context, the length L of the tether cable 8 between crane head 8 and cleaning robot 7 are being moved. The control unit then selects from the possible actuator configurations suitable for holding the cleaning robot 7 at the desired vertical position GP during its movement only those that prevent a collision between crane 6 and the tether cable 8 with the obstacles 25. (If no such actuator configuration exists, the control unit issues a warning message that crane 6 can no longer follow the cleaning robot 7, and preferably, the further movement of the cleaning robot 7 is then automatically blocked.)

In the present example, the angle of pull β is to be kept constant while the crane head 9 and the length L of the tether cable 8 are being moved. To bypass the chimney 26, the crane head 9 is raised along the lifting direction 28 (projected into the vertical plane), which runs along the (instantaneous) extension direction of the tether cable 8. During this lifting of the crane head 9, it also moves with a component perpendicular to the direction of travel 23 of the cleaning robot 7, cf. the direction of travel 29 of the crane head 9 (projected into the horizontal plane). In addition, some tether cable 8 is slackened during this lifting, i.e., the length L of the tether cable 8 between the crane head 9 and the cleaning robot 7 is lengthened so that the cleaning robot 7 maintains the desired vertical position GP.

The situation after the cleaning robot 7' has operated is shown in dotted lines. The second crane boom 15' has been raised above the chimney 26, thus preventing a collision with this obstacle 25. The length L' of the mooring cable 8' between the crane head 9' and the cleaning robot 7' is now significantly greater than the length L in the initial situation.

The 6 in a side view and 7 A front view illustrates an example of a cleaning robot 7 for the invention.

The cleaning robot 7 has a cleaning robot drive 30, which here is designed with a tracked chassis comprising two tracks 31a, 31b (the tracks 31a, 31b are in 7 (Disguised and therefore shown with dots). The cleaning robot drive 30 allows the cleaning robot 7 to move across its surface (e.g., a dirty surface).

The cleaning robot 7, in the configuration shown, has two front brushes 32a, 32b and two rear brushes 33a, 33b. The brushes 32a, 32b, 33a, 33b are each offset by one (in 6 , 7 The vertical brush axis is rotatable and therefore movable. Brushes 32a, 32b, 33a, and 33b can be used to clean the surface on which the cleaning robot 7 travels.

In addition, the cleaning robot 7 has nozzles 34 and 35 for a cleaning fluid. With nozzles 34 and 35, cleaning fluid can be applied to a surface. The cleaning robot 7 is sprayed with cleaning fluid on the soiled surface and brushes 32a, 32b, 33a, 33b. This enhances the cleaning effect of brushes 32a, 32b, 33a, 33b. The cleaning robot 7 is supplied with cleaning fluid via a supply line (not shown in detail, but see below). 8 (to this).

Furthermore, the cleaning robot 7 has a retaining eyelet (or suspension eyelet) 36 for a tethering rope. The retaining eyelet 36 is arranged laterally offset from a central plane ME of the cleaning robot 7.

The 8 shows a schematic side view of a section of System 2 of 1 in the area of the crane head 9 and the cleaning robot 7. The cleaning robot 7 sits on the surface 3 to be cleaned and is held by the taut retaining rope 8 and prevented from slipping.

The crane 6 is equipped with a sensor system 37, with which the current relative position of the cleaning robot 7 to the crane 6 (especially the stationary crane undercarriage) can be determined by measurements.

In the example shown, the sensor system 37 comprises a set of measuring sensors 38 on the crane head 9, in this case two optical cameras 39. In this example, the cameras 39 measure measuring marks 40 on the cleaning robot 7. This allows the relative position of the cleaning robot 7 to be determined relative to the crane head 9. Together with the known instantaneous actuator configuration of the crane 6, this allows the relative position of the cleaning robot to the crane 6 (or its stationary crane undercarriage) to be determined. This also allows the vertical position VKK of the cleaning robot 7 relative to the crane 6 to be checked at any time and, if necessary, corrected by moving the crane head 9 and/or adjusting the length L of the tether cable 8 between the crane head 9 and the cleaning robot 7. Accordingly, the vertical position VRR of the cleaning robot 7 can be adjusted to a desired vertical position GP.

The desired vertical position GP is typically predefined by programming and can, for example, be adopted as the measured vertical position of the cleaning robot 7 during initialization. The desired vertical position GP of the cleaning robot 7 is generally fixed while traversing a given horizontal cleaning path. To change the cleaning path, the desired vertical position GP can be changed, for example, according to the height difference to the next desired horizontal cleaning path (typically not abruptly, but gradually over time, at a moderate speed); the control unit of the crane 6 then adjusts the position of the crane head 6 (in particular its vertical position VKK) and/or the length L of the tether cable 8 accordingly.

The measuring sensors 38 can also determine a momentary orientation (rotational position) of the cleaning robot 7 relative to the crane head 9 and incorporate it into the tracking of the crane head 9 and/or the length L of the tether cable 8.

The tethering rope 8 is attached at its lower end to an attachment point 19 on the cleaning robot 7, specifically to a retaining eye 36. The attachment point 19 is located on the upsloping side of the intermediate plane ME of the cleaning robot 7. This ensures that when the cleaning robot 7 is suspended from the tethering rope 8 at attachment point 19, its lower part tilts towards the surface 3 to be cleaned.

The upper end of the retaining cable 8 is attached to the crane head 9. A pulley (winch) 41 is provided on the crane 9, specifically on the crane head 9, onto which the retaining cable 8 can be wound and unwound. This allows the length L of the retaining cable 8 between the crane head 9 and the cleaning robot 7 to be changed and adjusted.

In the example shown, a supply line 42 (shown as a dotted line) is also present, which runs from the crane 6, over the crane head 9, to the cleaning robot 7. Cleaning fluid is transported to the cleaning robot 7 via the supply line 42, typically from a reservoir on the crane 6 using a pump on the crane 6 (not shown in detail in the figure). 8 , cf. 1 (for this purpose). The cleaning fluid is then applied by the cleaning robot 7 when cleaning the soiled area 3. The supply line 42 is guided and held between the crane head 9 and the cleaning robot 7 by the retaining cable 8. For this purpose, the supply line 42 is connected to the retaining cable 8 at several attachment points 43, for example by a clamp.

• - einem Stromkabel, welches den Reinigungsroboter 7 mit elektrischem Strom versorgt;
• - einer oder mehreren Datenübertragungsleitungen, beispielsweise mit denen auszuführende Steuerbefehle an den Reinigungsroboter 7 übergeben werden oder ausgeführte Steuerbefehle vom Reinigungsroboter 7 berichtet werden, oder Sensordaten übertragen werden;
• - Hydraulikleitungen und/oder Pneumatikleitungen zum Reinigungsroboter;

jeweils nicht näher dargestellt.Supply line 42 includes at least one hose for the cleaning fluid. Supply line 42 may also include (at least in sections) and/or run concurrently with...

• - a power cable that supplies the cleaning robot 7 with electrical power;
• - one or more data transmission lines, for example, with which control commands to be executed are sent to the cleaning robot 7 are passed on or executed control commands are reported by the cleaning robot 7, or sensor data is transmitted;
• - Hydraulic lines and/or pneumatic lines to the cleaning robot;

not shown in detail.

The 9 Figure 7 illustrates the force distribution on a cleaning robot 7 when it is held by a tether 8 according to the invention, in a schematic side view. For simplicity, the cleaning robot 7 is depicted here as a cuboid, with all forces acting at its center of gravity SP, and frictional forces are generally neglected.

The cleaning robot 7 experiences a weight force G due to gravity, acting vertically downwards. On the steeply inclined, dirty surface 3 with a lateral slope α, this results in a normal force N perpendicular to the dirty surface 3 and a downward force H parallel to the dirty surface 3, with $$\text{N}=\text{G}*\text{cos}\left(\mathrm{\alpha }\right)$$ and $$\text{H}=\text{G}*\text{sin}\left(\mathrm{\alpha }\right).$$

The cleaning robot 7 pulls with a pulling force Z on the retaining cable 8, which is inclined at the pulling angle β to the vertical V towards the soiled surface 3. The pulling force Z can be decomposed into a pulling force component ZN perpendicular to the soiled surface 3, and a pulling force component ZH parallel to the soiled surface 3, with $$\text{ZN}=\text{Z}*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)$$ and $$\text{ZH}=\text{Z}*\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right).$$

In a state of equilibrium, when the cleaning robot 7 does not move along the soiled area 3 (i.e., along the "slope"), the following applies: $$\left|\text{H}\right|=\left|\text{ZH}\right|.$$

In the following, it is further desired that a maximum of 2/3 of the normal force N is canceled out by the tensile effect of the retaining rope 8, accordingly in the limiting case $$\left|\text{ZN}\right|=2\text{/}3*\left|\text{N}\right|.$$

• Die Gl. 2 und Gl. 4 eingesetzt in Gl. 5 ergibt $$\text{G}*\text{sin}\left(\mathrm{\alpha }\right)=\text{Z}*\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)$$ und umgeformt $$\text{G}/\text{Z}=\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{sin}\left(\mathrm{\alpha }\right).$$
• Die Gl. 1 und Gl. 3 eingesetzt in Gl. 6 ergibt $$\text{Z}*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)=2/3*\text{G}*\text{cos}\left(\mathrm{\alpha }\right)$$ und umgeformt $$\text{G}/\text{Z}=3/2*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{cos}\left(\mathrm{\alpha }\right).$$

Given a lateral inclination (also called angle of inclination) α, the necessary angle of pull β can then be determined as follows:

• Substituting equations 2 and 4 into equation 5 yields $$\text{G}*\text{sin}\left(\mathrm{\alpha }\right)=\text{Z}*\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)$$ and reshaped $$\text{G}/\text{Z}=\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{sin}\left(\mathrm{\alpha }\right).$$
• Substituting equations 1 and 3 into equation 6 yields $$\text{Z}*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)=2/3*\text{G}*\text{cos}\left(\mathrm{\alpha }\right)$$ and reshaped $$\text{G}/\text{Z}=3/2*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{cos}\left(\mathrm{\alpha }\right).$$

Equating equations 8 and 10 yields $$\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{sin}\left(\mathrm{\alpha }\right)=3/2*\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{cos}\left(\mathrm{\alpha }\right)$$ which can be transformed into $$\text{sin}\left(\mathrm{\alpha }+\mathrm{\beta }\right)/\text{cos}\left(\mathrm{\alpha }+\mathrm{\beta }\right)=3/2*\text{sin}\left(\mathrm{\alpha }\right)/\text{cos}\left(\mathrm{\alpha }\right)$$ and further $$\text{tan}\left(\mathrm{\alpha }+\mathrm{\beta }\right)=3/2*\text{tan}\left(\mathrm{\alpha }\right)$$ and even further $$\mathrm{\alpha }+\mathrm{\beta }=\text{arctan}\left[3/2*\text{tan}\left(\mathrm{\alpha }\right)\right].$$

This then yields the angle of pull β according to $$\mathrm{\beta }=\text{arctan}\left[3/2*\text{tan}\left(\mathrm{\alpha }\right)\right]-\mathrm{\alpha }\mathrm{.}$$

With a lateral inclination of α=25° in the limiting case, the necessary pull angle β is then 10.0°. With a lateral inclination of α=35°, the necessary pull angle β is 11.4°.

Reference symbol list:

1

Building

2

system

3

contaminated area

4

solar panel

5

Roof

6

crane

7

Cleaning robot

7'

Cleaning robot (according to the cleaning robot method)

8

Safety rope

8'

Holding rope (according to the cleaning robot's method)

9

Crane head

9'

Crane head (using the cleaning robot method)

10

telescopic system

11

Crane undercarriage

12

Crane superstructure (rotatable around DA1)

13

first crane boom

14

Swivel joint/cantilever joint (rotatable around DA2)

15

second crane boom

15'

second crane boom (using the cleaning robot method)

16

Swivel joint/cantilever joint (rotatable around DA3)

17

electronic control unit

18

crane truck

19

Attachment point/point of attack

20

storage container

21

Cleaning fluid

22

pump

23

horizontal travel path of the cleaning robot

24

horizontal travel path of the crane head

25

obstacle

26

chimney

27

Detection sensor system

28

(projected) lifting rate

29

(projected) direction of travel

30

Cleaning robot drive

31a, 31b

caterpillars

32a, 32b

front brushes

33a, 33b

rear brushes

34

nozzle

35

nozzle

36

retaining eyelet

37

Sensor system

38

Measuring sensors

39

optical camera

40

Measuring marks

41

Pulley/rope pulley

42

Supply line

43

Mounting points

DA1

(vertical) axis of rotation

DA2

(horizontal) axis of rotation

DA3

(horizontal axis of rotation)

FE

Level of the contaminated area

G

Weight of the cleaning robot

GP

desired position

H

Downslope force of the cleaning robot

HE

horizontal plane

L

Length of the mooring cable (between crane head and cleaning robot)

L'

Length of the tether rope (according to the cleaning robot's method)

ME

Middle level

N

Normal force of the cleaning robot

SE

Span plane

SP

focus

V

vertical

VKK

vertical position of the crane head

VRR

vertical position of the cleaning robot

Z

traction

ZH

Traction component parallel to the contaminated surface

ZN

Traction component perpendicular to the contaminated surface

α

Lateral tilt (angle of inclination)

β

angle of pull

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2014 108 465.0 [0012]

Cited non-patent literature

• HyCLEANER Photovoltaic Cleaning Robot: solarROBOT pro”, hyCLEANER GmbH & Co. KG, Gronau, DE, see URL https://hycleaner.de/photovoltaik-reinigungsroboter/ downloaded on 22.7.2024 [0002]
• H _Y CLEANER Photovoltaic Cleaning Robot: solarROBOT pro [0006]
• URL https://hycleaner.de/wp-content/uploads/2023/05/Zubehoer-Seitenfuehrungscaled.webp accessed on 22.07.2024 [0009]
• ROBSYS YTM Series” of Robsys Europe GmbH, Oer-Erkenschwick, DE, see URL https://rob-sys.de/ytm-serie/ downloaded on 22.7.2024 [0011]
• SERBOT Swiss Innovations GEKKO Solar Hightec Robot“ of SERBOT AG, Stans, CH [0013]
• https://www.serbot.ch/en/solar-panels-cleaning/gekko-solar-robot [0013]
• “Full PV yield for industrial buildings” by Klein Service GmbH, Jettingen-Scheppach, DE, see URL https:/www.kleinpv.de/industrie.html downloaded on 26.7.2024 [0014]

Claims (22)

A method for cleaning a soiled surface (3) with a cleaning robot (7, 7'), wherein in a cleaning operation the cleaning robot (7, 7') moves along the soiled surface (3) with a cleaning robot drive (30) and cleans the soiled surface (3) with at least one brush (32a, 32b, 33a, 33b), in particular wherein the brush (32a, 32b, 33a, 33b) is motor-movable on the cleaning robot (7, 7'), wherein the soiled surface (3) runs with a lateral inclination α relative to a horizontal plane (HE), with α>25°, in particular α>35°, characterized in that during the cleaning operation the cleaning robot (7, 7') is connected to a crane (6) via a tether cable (8, 8'), wherein the tether cable (8, 8') is attached to a crane head (9, 9') at an outer end a telescopic system (10) of the crane (6) leads to the cleaning robot (7, 7'), and that the cleaning robot (7, 7') is held by the retaining rope (8, 8') at a currently desired vertical position (GP) on the soiled surface (3) during the cleaning operation, during which the cleaning robot (7, 7') travels over the soiled surface (3) with its cleaning robot drive (30). Procedure according to Claim 1 , characterized in that a vertical position (VKK) of the crane head (9, 9') is higher than a vertical position (VRR) of the cleaning robot (7, 7'), and that the retaining rope (8, 8') between the crane head (9, 9') and the cleaning robot (7, 7') is freely tensioned. Procedure according to Claim 1 or 2 , characterized in that while the cleaning robot (7, 7') moves with its cleaning robot drive (30) on the soiled surface (3), an instantaneous position of the crane head (9, 9') and/or a length (L, L') of the tethering rope (8, 8') between the crane head (9, 9') and the cleaning robot (7, 7') is tracked in order to keep the cleaning robot (7, 7') at the currently desired vertical position (GP). Procedure according to Claim 3 , characterized in that the crane (6) has a sensor system (37) with which an instantaneous relative position of the cleaning robot (7, 7') to the crane (6) is repeatedly determined by measurements, and that on the basis of this determined relative position of the cleaning robot (7, 7') to the crane (6) the tracking of the instantaneous position of the crane head (9, 9') and/or the length (L, L') of the tethering rope (8, 8') is controlled. Procedure according to Claim 4 , characterized in that at least a future relative position of the cleaning robot (7, 7') to the crane (6), preferably also a future orientation of the cleaning robot (7, 7') to the crane (6), is predicted by means of a motion model and is taken into account when tracking the current position of the crane head (9, 9') and/or the length (L, L') of the tethering rope (8, 8'). Procedure according to Claim 4 or 5 , characterized in that the sensor system (37) of the crane (6) has one or more measuring sensors (38) on the crane head (9, 9') with which the measurements for determining the relative position of the cleaning robot (7, 7') to the crane head (9, 9'), and preferably also for the relative orientation of the cleaning robot (7, 7') to the crane head (9, 9'), are carried out, and that based on this determined relative position, and preferably also the determined relative orientation, of the cleaning robot (7, 7') to the crane head (9, 9') and based on known instantaneous travel settings of the crane (6), in particular an instantaneous rotation position of a crane superstructure (12), instantaneous telescoping states of booms (13, 15), instantaneous positioning angles of boom joints (14, 16) and/or a positioning position of a cable extension (41), the relative position, and preferably also the relative orientation, of the cleaning robot (7, 7') can be determined. 7') to the crane (6) is closed. Procedure according to one of the Claims 4 until 6 , characterized in that , within the framework of tracking the relative position of the crane head (9, 9') and/or the length (L, L') of the tethering rope (8, 8'), target positions for the crane head (9, 9') are repeatedly determined, and that movements of actuators of the crane (6) to achieve a respective target position of the crane head (9, 9') are calculated using methods of inverse kinematics. Procedure according to one of the Claims 3 until 7 , characterized in that the tracking of the instantaneous position of the crane head (9, 9') and/or the length (L, L') of the mooring rope (8, 8') is carried out such that the mooring rope (8, 8') is held at least approximately in a tension plane (SE), wherein the tension plane (SE) is vertically oriented and perpendicular to the contaminated surface (3). Procedure according to one of the Claims 3 until 8 , characterized in that the tracking of the instantaneous position of the crane head (9, 9') and/or the length (L, L') of the retaining rope (8, 8') such that the retaining rope (8, 8') is inclined at least approximately at an angle of pull β from the vertical (V) to a plane (FE) of the contaminated surface (3), with β≥10.0°, preferably β≥11.4°. Procedure according to Claim 9 characterized by the fact that $$\mathrm{\beta }\ge \text{arctan}\left[3/2*\text{tan}\left(\mathrm{\alpha }\right)\right]-\mathrm{\alpha }$$ is chosen. Procedure according to one of the Claims 3 until 10 , characterized in that the tracking of the instantaneous position of the crane head (9, 9') and/or the length (L, L') of the mooring rope (8, 8') is carried out such that the telescoping system (10) of the crane (6) and the mooring rope (8, 8') are guided around known obstacles (25) in the vicinity of the contaminated area (3), in particular wherein a detection sensor system (27) arranged on the crane (6) determines the known obstacles (25) by measurements. Procedure according to one of the Claims 3 until 11 , characterized in that the tracking of the current position of the crane head (9, 9') and/or the length (L, L') of the support rope (8, 8') is carried out automatically by an electronic control device (17) of the crane (6). Procedure according to Claim 12 , characterized in that at the beginning of the cleaning operation an initial vertical position of the cleaning robot (7, 7') is determined and stored in the electronic control unit (17), and that in the subsequent cleaning operation the electronic control unit holds the cleaning robot (7, 7') at this initial vertical position as the desired vertical position (GP) while traversing at least one horizontal cleaning path on the soiled surface (3). Method according to one of the preceding claims, characterized in that the cleaning robot (7, 7') travels at least sectionally along a horizontal direction of travel (23) on the soiled surface (3) during cleaning operation. Method according to one of the preceding claims, characterized in that a point of attack (19) of the retaining rope (8, 8') on the cleaning robot (7, 7') is offset relative to a median plane (ME) of the cleaning robot (7, 7') towards an upslope side of the cleaning robot (7, 7'). Method according to one of the preceding claims, characterized in that the cleaning robot (7, 7') continues to clean the soiled surface (3) with a cleaning fluid (21) during cleaning operation, and that the cleaning fluid (21) is provided via a supply line (42) which leads from the crane (6) over the crane head (9, 9') to the cleaning robot (7, 7'), in particular wherein a storage vessel (20) and a pump (22) for the cleaning fluid (21) are arranged on the crane (6) and the pump (22) pumps cleaning fluid (21) from the storage vessel (20) through the supply line (42) to the cleaning robot (7, 7'). System (2) for cleaning soiled surfaces (3), in particular wherein the system (2) is configured to carry out a method according to one of the preceding claims, whereby the system (2) comprises - a cleaning robot (7, 7') having a cleaning robot drive (30) with which the cleaning robot (7, 7') can move across a soiled surface (3), and which has at least one brush (32a, 32b, 33a, 33b) with which the soiled surface (3) can be cleaned as it moves across it, in particular wherein the brush (32a, 32b, 33a, 33b) on the cleaning robot (7, 7') is motor-movable, - a crane (6) comprising a telescoping system (10), a crane head (9, 9') at an outer end of the telescoping system (10), and an electronic control device (17), whereby the cleaning robot (7, 7') is suspended by a tether cable (8, 8') is connected to the crane (6), wherein the tethering rope (8, 8') leads from the crane head (9, 9') to the cleaning robot (7, 7'), and wherein the electronic control device (17) is configured to automatically hold the cleaning robot (7, 7') at a programmed, currently desired vertical position (GP) on the soiled surface (3) with the tethering rope (8, 8') during a cleaning operation, while the cleaning robot (7, 7') is moving on the soiled surface (3) with its cleaning robot drive (30). System (2) according to Claim 17 , characterized in that the electronic control device (17) is configured to track, during a cleaning operation in which the cleaning robot (7, 7') moves on the soiled surface (3) with its cleaning robot drive (30), an instantaneous position of the crane head (9, 9') and/or a length (L, L') of the tethering rope (8, 8') between the crane head (9, 9') and the cleaning robot (7, 7') in order to monitor the cleaning process. to hold the robot (7, 7') at the currently desired vertical position (GP). System (2) according to Claim 17 or 18 , characterized in that the cleaning robot drive (30) comprises a tracked chassis with at least two tracks (31a, 31b). Use of a system (2) according to one of the Claims 17 until 19 , for cleaning soiled surfaces (3), wherein the soiled surfaces (3) extend with a lateral inclination α relative to a horizontal plane (HE), with α>25°, in particular α>35°. Use according Claim 20 , characterized in that the contaminated areas (3) are formed by solar panels (4), in particular photovoltaic panels. Use according Claim 20 or 21 , characterized in that the contaminated areas (3) are arranged on the roof (5) of a building (1).