CN107966159A - Method for the navigation equipment of motor vehicle and for the motor vehicle that navigates - Google Patents

Abstract

This application involves the navigation equipment for motor vehicle and the method for the motor vehicle that navigates.In order to improve the method for the navigation equipment of vehicle and for the vehicle that navigates, it is proposed that, the acceleration transducer (10) being arranged in motor vehicle (11) is configured to determine the installation site of itself.

Description

Navigation device for a motor vehicle and method for navigating a motor vehicle

technical field

The invention relates to a navigation device for a motor vehicle and a method for navigating a motor vehicle.

Background technique

Navigation devices are known from the prior art which include acceleration sensors for determining the acceleration of the motor vehicle to be navigated. This acceleration sensor is arranged in the motor vehicle to detect acceleration data. In order to evaluate the acceleration data, however, the exact position of the acceleration sensor in the motor vehicle needs to be known. Only in this way can the measured acceleration data be adjusted in relation to the orientation of the motor vehicle. In order to determine the exact installation position of the acceleration sensor in the motor vehicle, it is also known to determine the installation position when installing the acceleration sensor. The disadvantage here, however, is that the mounting position is often not accurately determined during mounting and is not subsequently checked further. Alternatively, further sensors can be used whose task is to detect the installation position of the acceleration sensor in the motor vehicle. However such solutions are cumbersome and involve other electronic devices.

Contents of the invention

The object of the present invention is to improve a navigation system for a motor vehicle such that the installation position of an acceleration sensor can be determined and checked without additional sensors. Furthermore, the method for navigating a motor vehicle is correspondingly expanded.

This object is solved by a navigation device for a motor vehicle comprising an acceleration sensor for determining acceleration data of the motor vehicle, wherein the acceleration sensor is arranged, in particular incorporated, in an installation location in the motor vehicle. The acceleration sensor according to the invention is designed to determine the installation position. In other words, the acceleration sensor itself is designed to detect its own installation position in the motor vehicle. In order to obtain the exact mounting position, no additional sensors are required. The only data required for the acceleration sensor to determine its installation position are the acceleration data of the motor vehicle measured by the acceleration sensor and the data once determined with respect to the coordinate system of the acceleration sensor. In particular, the coordinate system of the acceleration sensor has been determined once. This is usually done by the manufacturer of the acceleration sensor. The x-axis, y-axis and z-axis of the acceleration sensor are determined at once, wherein acceleration data of the acceleration sensor with respect to these axes can be output. The three-dimensional Cartesian coordinate system, in particular the right-handed coordinate system, of the acceleration sensor is referred to below as the sensor coordinate system. Acceleration sensors refer in particular to 3D acceleration sensors which preferably measure acceleration continuously in all three axes (x, y and z).

The motor vehicle also has its own coordinate system, which is referred to below as the vehicle coordinate system. The vehicle coordinate system is also a three-dimensional Cartesian coordinate system, especially a right-handed coordinate system. Here, the x-axis of the coordinate system corresponds to the straight-line driving direction of the vehicle, while the z-axis is perpendicular to the plane on which the vehicle is located and points upwards. The y-axis points to the side of the motor vehicle.

Ideally, the sensor coordinate system and the vehicle coordinate system coincide with each other, or the corresponding axes of the two different coordinate systems are parallel to each other. However, it often occurs in practice that the sensor coordinate system does not correspond to the vehicle coordinate system. In particular, the sensor x-axis is offset by an angle α _x from the x-axis of the vehicle coordinate system. The same applies to the y- and _{z-axes of the sensor coordinate system, which are likewise offset by angles αy and αz from} the corresponding axes of the vehicle coordinate system. The aforementioned angle is defined as the installation angle. In other words, the mounting angle indicates how the vehicle coordinate system can be transformed into the sensor coordinate system, or vice versa. This is achieved by a rotation determined by the mounting angle.

Advantageously, the navigation device for a motor vehicle is designed to determine the installation position of the acceleration sensor by ascertaining the installation angle. In particular, the motor vehicle can be configured as four-wheeled or two-wheeled.

The invention includes a method for navigating a motor vehicle, in which an acceleration sensor according to the invention is used. In this case, the method includes determining an installation location of an acceleration sensor for acquiring acceleration data of the motor vehicle. In particular, the installation position is determined continuously. In addition, the installation position is preferably determined automatically, and it is also preferable not to use an additional sensor for determining the installation position.

In order to obtain the mounting angle, the movement of the motor vehicle is detected. For this purpose, the current acceleration data detected or received by the acceleration sensor are compared with previous, ie at least earlier detected or received acceleration data. The difference between the currently received acceleration data and the previously received acceleration data is compared with a predetermined threshold value. The state "moving" is detected as soon as the difference between the acceleration data received at the present time and the acceleration data received previously exceeds a defined threshold value. In particular, the method comprises comparing, preferably continuously comparing, currently received acceleration data with previously received acceleration data. Furthermore, the comparison with a predetermined threshold value preferably takes place continuously. Only when a threshold is exceeded is the vehicle state assigned to the specific state "Motion", or a previously identified vehicle state is changed. To prevent fluctuations, the method steps are decoupled by hysteresis.

Below the threshold, previously identified motion states are maintained and no new motion states are assigned.

Further preferably, the method includes identifying the state "no motion". The state "no motion" is distinguished from the state "motion" with constant velocity by obtaining the amount of change in the acceleration value. That is, it is preferable to continuously acquire the amount of change between the current acceleration value and the acceleration value measured not long ago (for example, one second ago). In particular, the effect that a stationary vehicle provides significantly smaller variations than a vehicle traveling at a constant speed is exploited here. Theoretically, the acceleration is zero in both cases (vehicle stationary, vehicle traveling at constant speed). In practice, a vehicle traveling at a constant speed is continuously subjected to different accelerations which occur due to motor vibrations, road irregularities, minimal steering movements, etc., which are present during traveling at a constant speed. This means that the "noise", ie the change in the acceleration value, which is compared in particular with a predefined threshold value, is significantly higher in a vehicle that is actually moving than in a stationary vehicle. If the amount of change exceeds the threshold, it is identified as constant speed motion, and if it is below the threshold, it is identified as the state "no motion".

Advantageously, the state "braking" is recognized when the state "moving" transitions into the state "no moving". As soon as the state "braking" is detected, in particular a braking vector or a braking direction vector is formed. The braking vector is formed in particular from acceleration data received at the moment of the state "braking" and previously received acceleration data. The previously received acceleration data are traced back in time, for example at most 5 seconds, preferably 3 seconds, in particular 2 seconds, before the state "braking" is detected. Advantageously, the method acquires the magnitude of the braking vector and discards the resulting braking vector when the braking vector is small with respect to its magnitude. For this, the modulus must exceed the specified limits. This is used to eliminate misidentified states.

The braking vector is a very important measurement because this braking vector points in the negative x direction of the vehicle. Therefore, the braking vector defines the negative x-direction of the vehicle coordinate system. The x-axis of the vehicle coordinate system can thus be derived from the braking vector.

Further preferably, the method forms a gravity vector from the acceleration data received at the moment of the state "no motion" when the state "no motion" is detected. As long as the vehicle is in the state "no motion", the acceleration sensor only measures the gravitational acceleration pointing in the positive z direction of the vehicle. Thus, the gravity vector or in other words the gravity direction vector points in the positive z direction of the vehicle coordinate system.

Preferably, the braking vector and the gravity vector are measured at a temporally close distance from one another. This means that when the state "moving" transitions into the state "no moving" and thus the state "braking" is detected, not only a braking vector is formed, but also a gravity vector is formed immediately thereafter.

The minimum prerequisite for knowing the vehicle coordinate system is two linearly independent vectors, which are determined by the braking vector and the gravity vector, since the y-axis is automatically derived from the other two axes. Since the acceleration sensor has knowledge of its own sensor coordinate system, the acceleration sensor can determine the installation angle between a determined axis of the vehicle coordinate system and a known axis of its own coordinate system. This installation angle is formed from the vectors of two different coordinate systems by means of the product of quantities.

In particular, the method comprises forming a rotation matrix from the mounting angles, wherein the rotation matrix defines a rotation between two different coordinate systems. With the aid of the rotation matrix, the actual acceleration vector of the motor vehicle with respect to its coordinate system can be obtained.

The mounting positions are preferably detected continuously. In particular, the installation position is always detected when the state "braking" is detected and the braking vector is sufficiently large in terms of modulus. This achieves a continuous self-calibration of the installation position of the acceleration sensor and thus ensures that the acquired vehicle acceleration data are always as correct as possible.

The data acquired for calculating the installation angle (ie the gravity vector and the braking vector) are gathered in memory and each newly calculated data set is compared with the data set already present in memory. If the deviation from the data set previously present in the memory is too great, ie exceeds a predetermined limit, the data set is marked as invalid and thus discarded. If the deviation from the valid data set present in the memory is small, ie below a defined limit, the data set is marked as valid and used. A statistically optimal data set for all active angles is formed via the memory. In addition, mathematical methods such as mean, median, mode and/or the like are preferably used. Use the value of the best data set acquired to determine the rotation angle. These rotation angles define the exact mounting position of the acceleration sensor.

In particular, the method also includes the use of GPS data for determining the installation position of the acceleration sensor. The use of GPS data is especially advantageous as long as two-wheelers, mostly motorcycles, are used as motor vehicles. Two-wheeled vehicles are characterized in that they are not always straight and calm after braking up to a standstill due to their roll, making it difficult to determine a standstill based only on data measured by an acceleration sensor. In order to counteract this effect, acceleration or braking from a previous calm driving is detected with the aid of the GPS signal. This presupposes the previous calm driving. That is, the method includes constantly reading GPS data. The installation location is only recognized if the following conditions are fulfilled:

· The vehicle travels in a straight line, which means that the GPS direction is constant.

• The vehicle travels without a slope, which means that the GPS altitude is constant.

• The vehicle travels at a constant speed, that is to say the GPS ground speed (GPS speed with respect to the ground, for example with respect to sea level) is constant.

As long as the vehicle state described above is reached, the vehicle travels at a constant speed, so that no acceleration occurs. Also in this case, only the gravitational acceleration is measured by the acceleration sensor, so that the gravitational vector can be determined from these data.

If a significant GPS speed change is identified from the conditions described above, the vehicle has accelerated or braked from calm driving. According to the method described above, the acceleration vector or braking vector for this state change is again used to determine the installation position. Based on the GPS data, positive acceleration vectors, ie acceleration vectors pointing in the positive x-direction of the vehicle, can also be used here. Misinterpretations of positive accelerations were ruled out by GPS information.

Description of drawings

The invention is explained in detail below by way of example with reference to the drawings. Which is shown in the schematic diagram:

Figure 1: Sensor with sensor coordinate system and motor vehicle with vehicle coordinate system;

FIG. 2 : a state diagram of the state of motion of the motor vehicle; and

Figure 3: Time course of different variables as the state of the motor vehicle changes.

Detailed ways

FIG. 1 shows in the left half of the diagram an acceleration sensor 10 , about which a sensor coordinate system 12 is defined. The sensor coordinate system 12 includes an x-axis 12a, a y-axis 12b and a z-axis 12c. Motor vehicle 11 with vehicle coordinate system 13 is shown in the right half of FIG. 1 . The vehicle coordinate system 13 also includes an x-axis 13a, a y-axis 13b and a z-axis 13c.

Acceleration sensor 10 is arranged in motor vehicle 11 . Typically, after the acceleration sensor 10 is installed, the coordinate axes 12a, 12b, 12c of the acceleration sensor do not coincide with the axes 13a, 13b, 13c of the vehicle coordinate system 13, but the corresponding axis pairs 12a and 13a, 12b and 13b, 12c and 13c are at an angle to each other. The angle between the x-axis 12 a of the sensor coordinate system 12 and the x-axis 13 a of the vehicle coordinate system 13 is referred to as angle α _x . Correspondingly, angles between the y-axes or the z-axes of the different coordinate systems form the angles α _y and α _z . These angles are called installation angles. In order to be able to use acceleration data measured by acceleration sensor 10 relating to motor vehicle 11 , these data must be evaluated with respect to vehicle coordinate system 13 . For this purpose, the installation angle needs to be determined, so that the measured acceleration data can be converted into the vehicle coordinate system 13 by means of the rotation matrix formed by the installation angle.

Different states of motion 14 of motor vehicle 11 are shown in FIG. 2 . The state "no movement" 16 is shown in the upper part of the figure, while the state "movement" 15 is shown in the lower part of the figure. As soon as the state “no motion” 16 is detected above the state “movement” 15 , the state “braking” 17 is detected.

In contrast, the state “just started” 18 is recognized as soon as the state of motion 14 changes from state “no motion” 16 to state “motion” 15 . Whenever the acceleration sensor 10 detects the state “braking” 17 , it detects the gravity vector and the braking vector and from these two linearly independent vectors can determine the vehicle coordinate system 13 and thus determine the installation angle.

FIG. 3 shows the time course of various variables when motor vehicle 11 switches motion state 14 . In this case, FIG. 3 shows different variables in four graphs with respect to time 19 in a temporal relationship to one another.

The actual movement 20 of the motor vehicle 11 is shown in the second diagram from the top. Velocity 21 is shown in the third graph from the top, and acceleration 22 is shown in the bottommost graph. The lowermost graph thus shows in simplified form the data measured by acceleration sensor 10 based on actual movement 20 . The motion state 14 detected by the acceleration sensor 10 is shown in the first graph from the top.

As can be seen from the second figure counted above, the motor vehicle 11 initially does not move. This means that velocity 21 and acceleration 22 are zero. The acceleration sensor therefore only measures noise, so that it assigns the movement to the state “no movement” 16 . To be precise, acceleration sensor 10 in this case only measures a constant gravitational acceleration due to gravity.

Motor vehicle 11 then starts moving itself. This means that the speed 21 increases. Motor vehicle 11 becomes faster during acceleration time 26 . This is also shown in the bottommost graph, where the acceleration 22 first increases and then remains approximately constant. After a delay time 24 related to the start of the motor vehicle 11 , the movement of the motor vehicle 11 is assigned to the state “just started” 18 . Subsequent to being classified as state "Motion" 15.

During the subsequent movement of motor vehicle 11 at constant speed 21 , acceleration sensor 11 detects no acceleration 22 (except for the constant gravitational acceleration). However, because the motion recognition part continuously determines a variation value (current acceleration value−previous acceleration value) that is higher than the threshold value for identifying a static state due to a larger noise value, it is possible to exclude the stationary state. state, so that the motor vehicle 11 must be moving at a constant speed 21 . The state "Motion" 15 is therefore maintained.

During the braking time 27, the speed 21 decreases until the standstill. During the braking time 27 , the acceleration sensor 11 detects a negative acceleration 22 . Next, the acceleration sensor 11 measures no acceleration 22 (except for constant gravitational acceleration). The acceleration sensor acquires the state “braking” 17 after a delay time 25 . Acceleration sensor 10 then assigns the movement of motor vehicle 11 to state “no movement” 16 .

In each transition from the state "Motion" 15 to the state "No Motion" 16, that is, when the state "Braking" 17 is recognized, not only a gravity vector is formed, which is based on the data of the state "No Motion", but also A braking vector is formed, which is obtained from the acceleration data measured during the state "braking" 17 and the preceding period. Due to the time delay 25 in braking, the period before the state “state” 17 is detected includes the actual braking process.

Claims (9)

1. a kind of navigation equipment for motor vehicle,

Wherein, the navigation equipment includes being used to determine the acceleration transducer (10) of the acceleration information of motor vehicle (11), its In, the acceleration transducer is disposed in installation site in motor vehicle (11),

It is characterized in that,

The acceleration transducer (10) is configured to determine the installation site.

2. a kind of be used for the method for motor vehicle of navigating, wherein, using acceleration transducer according to claim 1 (10),

It is characterized in that, the described method includes the installation site for determining the acceleration transducer (10).

3. the method described in accordance with the claim 2 for the motor vehicle that navigates,

It is characterized in that,

The installation site of the acceleration transducer (10) passes through established angle (α_x、α_y、α_z) be defined, wherein it is determined that described The installation site of acceleration transducer (10) includes obtaining the established angle (α_x、α_y、α_z)。

4. it is used for the method for motor vehicle of navigating according to described in Claims 2 or 3,

It is characterized in that,

The movement of the motor vehicle (11) is identified to obtain the established angle (α_x、α_y、α_z),

Wherein, by the acceleration information that the acceleration transducer (10) current time receives and previously received acceleration Data are compared, and wherein, when the acceleration information that the current time receives and the previously received acceleration When difference between degrees of data exceedes defined threshold value, then state " movement " (15) is recognized.

5. it is used for the method for motor vehicle of navigating according to any one of claim 2 to 4,

It is characterized in that,

The described method includes identification state " not to move ".

6. it is used for the method for motor vehicle of navigating according to described in claim 4 and 5,

It is characterized in that,

When being transitioned into the state from the state " movement " (15) and " not moving " (16), state " braking " is recognized (17)。

7. it is used for the method for motor vehicle of navigating according to described in claim 6,

It is characterized in that,

When recognizing the state " braking " (17), braking vector is formed.

8. it is used for the method for motor vehicle of navigating according to any one of claim 5 to 7,

It is characterized in that,

When recognizing the state and " not moving " (16), by received at the time of the state " does not move " (16) Acceleration information formed gravity vector.

9. it is used for the method for motor vehicle of navigating according to any one of claim 2 to 8,

It is characterized in that,

The acquisition of the installation site continuously carries out.