JP2016017824A - Acceleration correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acceleration correction device with which it is possible to improve the accuracy of correcting the detection value of an acceleration sensor.SOLUTION: An ESP controller determines, when it is determined that a vehicle is running at a certain speed and that the running surface the vehicle is running down is flat, that a correction amount calculation enabled state is on (step S42); calculates a standard deviation Gs of a moderated value of acceleration Gif in which the detection value of an acceleration sensor is moderated (step S46); determines, when the calculated standard deviation Gs is less than or equal to a prescribed value, that a correction amount updating enabled state is on (step S47); and calculates a moderated value of sensor correction amount Gerr as a correction amount for the detection value of the acceleration sensor and updates the correction amount (step S48).SELECTED DRAWING: Figure 9

Description

  The present invention relates to an acceleration correction device that corrects a detection value of an acceleration sensor that detects acceleration of a vehicle.

  2. Description of the Related Art Conventionally, piezoelectric and servo sensors are known as acceleration sensors that detect vehicle acceleration. Such an acceleration sensor causes a drift error in its detection value due to variations in quality, aging deterioration, attachment error, and the like.

  In order to eliminate such a drift error, for example, in Patent Document 1, when the detected value of the vehicle speed is equal to or greater than a predetermined value, the steering angle is neutral, and the throttle opening is kept constant. During the period when the vehicle is determined to be in a steady running state and the vehicle is determined to be in a steady running state, the average value of acceleration sensor detection values is calculated as a drift amount (drift error), and the calculated drift amount An apparatus for correcting the detection value of the acceleration sensor by subtracting the value from the detection value of the acceleration sensor has been proposed.

  Further, in Patent Document 2, it is determined that the vehicle is traveling straight when the difference between the rotational speeds of the left and right wheels of the vehicle is equal to or less than a predetermined value, and the period is determined that the vehicle is traveling straight. A device that corrects the detection value of the acceleration sensor by calculating the average value of the acceleration signal output from the acceleration sensor as a drift amount (drift error) and subtracting the calculated drift amount from the detection value of the lateral acceleration sensor has been proposed. ing.

  In Patent Document 3 and Patent Document 4, in a four-wheel drive vehicle having a torque distribution clutch that distributes torque between the front and rear wheels, the road surface gradient in the front-rear direction of the vehicle is estimated, and the difference in rotational speed between the left and right wheels of the vehicle is estimated. When it is less than or equal to a predetermined value and the output of the prime mover is within a predetermined range, it is determined that the vehicle is in a flat road straight traveling constant speed traveling state, and the vehicle is determined to be in a flat road straight traveling constant speed traveling state. A device that corrects the detection value of the acceleration sensor by calculating the average value of the detection values of the longitudinal acceleration sensor as a drift amount (drift error) and subtracting the calculated drift amount from the detection value of the longitudinal acceleration during the period Each has been proposed.

Japanese Patent Publication No. 07-40039 Japanese Patent Publication No. 07-40043 JP 2006-250947 A JP 2006-250948 A

  However, the apparatus proposed in Patent Document 1 has a problem that the accuracy of correction with respect to the detection value of the acceleration sensor is lowered when the vehicle is traveling on a slope. Moreover, since the apparatus proposed in Patent Document 2 does not consider the influence of the road gradient in the front-rear direction of the vehicle, there is a problem that the accuracy of correction with respect to the detection value of the acceleration sensor is reduced.

  In addition, since the devices proposed in Patent Document 3 and Patent Document 4 do not take into account variations in the detected value of the acceleration sensor due to vibration components of the detected value of the acceleration sensor, the accuracy of correction for the detected value of the acceleration sensor is high. There was a problem that it would decrease.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide an acceleration correction apparatus that can improve the accuracy of correction of the detection value of the acceleration sensor.

  One aspect of the acceleration correction apparatus according to the present invention that solves the above-described problem is an acceleration correction apparatus that corrects a detection value of an acceleration sensor that detects acceleration of a vehicle, and whether or not the vehicle is traveling at a constant speed. The vehicle is traveling at a constant speed by a constant speed traveling determination unit that determines whether the vehicle is traveling, a flat traveling determination unit that determines whether or not the traveling surface on which the vehicle is traveling is flat, and a constant speed traveling determination unit And the correction amount of the detection value of the acceleration sensor is calculated based on the detection value of the acceleration sensor based on the detection value of the acceleration sensor when the flat traveling determination unit determines that the traveling surface on which the vehicle is traveling is flat. A correction amount calculation unit, and a correction unit that corrects the detection value of the acceleration sensor based on the correction amount calculated by the correction amount calculation unit, the correction amount calculation unit of the correction amount of the detection value of the acceleration sensor Calculate the standard deviation On condition that the standard deviation is less than a specified value, and is configured to update the correction amount of the detection value of the acceleration sensor.

  As described above, the present invention can provide an acceleration correction apparatus that can improve the accuracy of correction with respect to the detection value of the acceleration sensor.

FIG. 1 is a hardware configuration diagram showing a main part of a vehicle equipped with an acceleration correction device according to an embodiment of the present invention. FIG. 2 is a mounting diagram showing a main part of a vehicle equipped with the acceleration correction device according to the embodiment of the present invention. FIG. 3 is a functional block diagram of the acceleration correction apparatus according to the embodiment of the present invention. FIG. 4 is a conceptual diagram showing a torque map referred to by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 5 is a flowchart showing an acceleration correction operation of the acceleration correction apparatus according to the embodiment of the present invention. FIG. 6 is a flowchart showing a constant speed traveling determination process executed by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 7 is a flowchart showing a flat surface running determination process executed by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 8 is a flowchart showing a straight traveling determination process executed by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 9 is a flowchart showing a correction amount calculation process executed by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 10 is a flowchart showing a correction process executed by the acceleration correction apparatus according to the embodiment of the present invention. FIG. 11 is a conceptual diagram for explaining the operation of the acceleration correction apparatus according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1 to FIG. 3, a vehicle 1 equipped with an acceleration correction device according to an embodiment of the present invention includes an internal combustion engine 2 as a drive source of the vehicle 1, and an engine controller that controls the engine 2. 3, a transmission 4, a hydraulic circuit 5 that changes a shift speed formed in the transmission 4, a transmission controller 6 that controls the transmission 4 via the hydraulic circuit 5, and an ESP that controls the running state of the vehicle 1 (Electronic Stability Program) The controller 7 is included.

  In the present embodiment, the engine 2 is configured by a four-cycle engine in which a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke is performed, and ignition is performed during the compression stroke and the expansion stroke. Has been.

  The engine controller 3 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, an output port, and a computer unit having a network module. It is configured.

  The network module can communicate with other controllers such as the transmission controller 6 and the ESP controller 7 via an in-vehicle LAN (Local Area Network) conforming to a standard such as CAN (Controller Area Network) or FlexRay. It has become.

  The ROM of the engine controller 3 stores a program for causing the computer unit to function as the engine controller 3 along with various control constants and various maps.

  That is, in the engine controller 3, the computer unit functions as the engine controller 3 when the CPU executes a program stored in the ROM.

  Various sensors such as an engine speed sensor 10 for detecting the engine speed of the engine 2 are connected to the input port of the engine controller 3. In addition, various control objects for controlling the engine 2 are connected to the output port of the engine controller 3.

  The engine controller 3 controls various control objects connected to the output port based on information obtained from various sensors connected to the input port. For example, the engine controller 3 configures the torque detector 30 that detects the output torque of the engine 2 based on the output requested of the engine 2 and the detection value of the engine speed sensor 10.

  The engine controller 3 transmits information indicating the detected output torque of the engine 2 to other controllers such as the transmission controller 6 and the ESP controller 7.

  In the present embodiment, the transmission 4 is constituted by a torque converter type automatic transmission, and shifts the power generated by the engine 2. The transmission 4 may be constituted by a transmission other than the torque converter type automatic transmission as long as the formed gear stage can be electrically identified.

  The transmission 4 includes a torque converter, a plurality of planetary gear mechanisms, and a plurality of friction engagement elements that constitute clutches and brakes. The transmission 4 supplies hydraulic oil supplied from a hydraulic circuit 5 controlled by a transmission controller 6. Accordingly, by changing the gripping of each friction engagement element, a desired gear stage is formed.

  The transmission controller 6 includes a computer unit that includes a CPU, a RAM, a ROM, a flash memory, an input port, an output port, and a network module.

  The network module can communicate with other controllers such as the engine controller 3 and the ESP controller 7 via an in-vehicle LAN conforming to a standard such as CAN or FlexRay.

  The ROM of the transmission controller 6 stores a program for causing the computer unit to function as the transmission controller 6 along with various control constants and various maps.

  That is, in the transmission controller 6, the computer unit functions as the transmission controller 6 when the CPU executes a program stored in the ROM.

  For example, the transmission controller 6 changes the gear stage formed in the transmission 4 by controlling the hydraulic circuit 5 based on the operating state of the engine 2 and the detected value of a shift position sensor (not shown). .

  In addition, the transmission controller 6 is configured to transmit information indicating the shift speed to be formed in the transmission 4 to other controllers such as the engine controller 3 and the ESP controller 7.

  The ESP controller 7 is configured by a computer unit including a CPU, a RAM, a ROM, a flash memory, an input port, an output port, and a network module.

  The network module can communicate with other controllers such as the engine controller 3 and the transmission controller 6 via an in-vehicle LAN conforming to a standard such as CAN or FlexRay.

  A program for causing the computer unit to function as the ESP controller 7 is stored in the ROM of the ESP controller 7 together with various control constants and various maps.

  That is, in the ESP controller 7, the computer unit functions as the ESP controller 7 when the CPU executes a program stored in the ROM.

  Various sensors such as an acceleration sensor 11 that detects the acceleration of the vehicle 1, a vehicle speed sensor 12 that detects the speed of the vehicle 1, and a steering angle sensor 13 that detects the steering angle of the vehicle 1 are provided at the input port of the ESP controller 7. Is connected.

  The vehicle speed sensor 12 in the present embodiment is configured by wheel speed sensors 12FR, 12FL, 12RR, and 12RL that detect the rotational speeds of the wheels provided to the front right, left front, right rear, and left rear of the vehicle 1, respectively.

  Various control objects are connected to the output port of the ESP controller 7. The ESP controller 7 is configured to control various control objects connected to the output port based on information obtained from various sensors connected to the input port.

  In the present embodiment, the ESP controller 7 constitutes an acceleration correction device 31 that corrects the detection value of the acceleration sensor 11. The acceleration correction device 31 may be configured by other controllers such as the engine controller 3 and the transmission controller 6.

  The acceleration correction device 31 corrects the detection value of the acceleration sensor 11, such as four-wheel steering control, active suspension control, longitudinal torque distribution control, neutral control, hill hold control, erroneous start suppression control, and idling stop control. It can be applied to various controls that require eleven detection values.

  Here, the four-wheel steering control is control for independently steering each wheel in accordance with the driving state of the vehicle 1 and the traveling environment. The active suspension control is control for changing a damping coefficient of a suspension provided for each wheel in accordance with the traveling state of the vehicle 1. The front-rear torque distribution control is control for changing the distribution of torque transmitted to the front and rear wheels in accordance with the traveling state of the vehicle 1 when the vehicle 1 is configured by a four-wheel drive vehicle.

  The neutral control is a control that minimizes the load applied to the engine 2 by setting the gear stage formed in the transmission 4 to neutral while the vehicle 1 is stopped. The hill hold control is a control for operating the brake so that the vehicle 1 does not slide backward when the traveling surface of the vehicle 1 is inclined so as to rise in the traveling direction.

  The erroneous start suppression control is a control that suppresses sudden start due to a mistake in stepping on the accelerator pedal and the brake pedal. When there is an object in the traveling direction of the vehicle 1, the engine 2 as a prime mover is depressed. It is control which suppresses the output of. The idling stop control is a control for stopping the engine 2 when the output of the engine 2 is not required.

  The above-described controls such as four-wheel steering control, active suspension control, longitudinal torque distribution control, neutral control, hill hold control, erroneous start suppression control, idling stop control, and the like are controlled by the engine controller 3 according to the control target of each control. And executed by various controllers such as the transmission controller 6 and the ESP controller 7.

  Here, the controller that does not constitute the acceleration correction device 31 receives a signal representing the corrected acceleration from the controller that constitutes the acceleration correction device 31 via the in-vehicle LAN. That is, in the present embodiment, the engine controller 3 and the transmission controller 6 each receive a signal representing the acceleration corrected by the ESP controller 7 as necessary.

  In the present embodiment, the ESP controller 7 calculates the vehicle speed VS according to the following formula (1) using the wheel speeds WSl and WSr of the wheels that are not drive wheels in order to detect the vehicle speed more accurately. It has become.

VS = (WSl + WSr) × Kwtv (1)

  Here, the wheel speed WSl is the rotational speed of the left wheel that is not the driving wheel, and the wheel speed WSr is the rotational speed of the right wheel that is not the driving wheel. For example, when the vehicle 1 is configured by a front wheel drive vehicle, the wheel speed WSl represents the rotation speed of the left rear wheel, and the wheel speed WSr represents the rotation speed of the right rear wheel. The coefficient Kwtv is a constant determined according to the wheel diameter.

  When the vehicle 1 is configured by a four-wheel drive vehicle, the ESP controller 7 averages the wheel speeds detected by the wheel speed sensors 12FR, 12FL, 12RR, and 12RL, and multiplies the coefficient according to the wheel diameter. Thus, the vehicle speed VS may be calculated.

  The ESP controller 7 indicates that the change amount of the detection value of the vehicle speed sensor 12 has an absolute value smaller than the first specified value, and the absolute value of the change value of the detection value of the acceleration sensor 11 is smaller than the second specified value. As a condition, it is determined that the vehicle 1 is traveling at a constant speed. Here, the first specified value and the second specified value are adaptive values obtained experimentally in advance.

  More specifically, when the calculation cycle of the vehicle speed VS that is a detection value of the vehicle speed sensor 12 is Tvs, the ESP controller 7 calculates the vehicle speed change amount VSd using the vehicle speed VS calculated this time and the vehicle speed VSb calculated last time. It is calculated sequentially according to the following formula (2).

VSd = (VS−VSb) / TvS (2)

  In addition, when the calculation period of the acceleration Gi that is the detection value of the acceleration sensor 11 is Tg, the ESP controller 7 shows the acceleration change amount Gd using the acceleration Gi calculated this time and the acceleration Gb calculated last time. It is calculated sequentially according to the mathematical formula (3).

Gd = (Gi−Gb) / Tg (3)

  Further, the ESP controller 7 removes unnecessary vibration components of the calculated vehicle speed change amount VSd. As an example, the ESP controller 7 sequentially calculates the vehicle speed change amount smoothed value VSdf obtained by rounding the vehicle speed change amount VSd according to the following formula (4). In Equation (4), the smoothing teaching is Kvsdf, and the previous vehicle speed change smoothing value is VSdfo. Moreover, the annealing teacher Kvsdf is a fitness value from 0 to 1.

VSdf = Kvsdf × VSdfo + (1−Kvsdf) × VSd (4)

  Further, the ESP controller 7 is configured to remove unnecessary vibration components of the calculated acceleration change amount Gd. As an example, the ESP controller 7 sequentially calculates an acceleration change amount smoothed value Gdf obtained by accelerating the acceleration change amount Gd according to the following equation (5). In Equation (5), the smoothing teaching is Kgdf, and the previous acceleration change smoothing value is Gdfo. Further, the annealing teacher Kgdf is a fitness value from 0 to 1.

Gdf = Kgdf × Gdfo + (1−Kgdf) × Gd (5)

  Based on the thus calculated vehicle speed change amount smoothing value VSdf and acceleration change amount smoothing value Gdf, the ESP controller 7 determines whether or not the vehicle 1 is traveling at a constant speed. 32.

  Specifically, the ESP controller 7 confirms that the absolute value of the vehicle speed change amount smoothing value VSdf is smaller than the first specified value, and that the absolute value of the acceleration change amount smoothing value Gdf is smaller than the second specified value. As a condition, it is determined that the vehicle 1 is traveling at a constant speed.

  Further, the ESP controller 7 is configured to remove unnecessary vibration components of the calculated vehicle speed VS. As an example, the ESP controller 7 sequentially calculates the vehicle speed smoothed value VSf obtained by smoothing the vehicle speed VS according to the following formula (6). In Equation (6), let the smoothing teaching be Kvsf and the previous vehicle speed smoothing value be VSfo. Moreover, the annealing teacher Kvsf is a fitness value from 0 to 1.

VSf = Kvsf × VSfo ten (1−Kvsf) × VS (6)

  Further, the ESP controller 7 is configured to remove an unnecessary vibration component of the output torque Trq represented by the information transmitted from the engine controller 3. As an example, the ESP controller 7 sequentially calculates the output torque smoothed value Trqf obtained by smoothing the output torque Trq according to the following formula (7). In Equation (7), let the annealing teaching be Ktrqf and the previous output torque annealing value be Trqo. Moreover, the annealing teacher Ktrqf is a fitness value from 0 to 1.

Trqf = Ktrqf × Trqo + (1−Ktrqf) × Trq (7)

  In the present embodiment, the ESP controller 7 constitutes a flat traveling determination unit 33 that determines whether or not the traveling surface on which the vehicle 1 is traveling is flat. Specifically, the ESP controller 7 sets the vehicle 1 on the condition that the output torque smoothing value Trqf is within a specified range according to the vehicle speed smoothing value VSf and the gear stage formed by the transmission 4. It is determined that the running surface is flat. Here, the gear stage formed by the transmission 4 is transmitted from, for example, the transmission controller 6.

  The value of the output torque Trqh of the engine 2 in the vehicle 1 traveling on a flat traveling surface depends on the vehicle specifications. However, in order to maintain a constant speed unless the gear stage formed in the transmission 4 is changed. Therefore, the output torque Trqh of the engine 2 required for the vehicle increases as the vehicle speed increases.

  Therefore, a torque map as shown in FIG. 4 representing the relationship between the vehicle speed and the output torque Trqh is stored in the ROM of the ESP controller 7 for each gear stage formed in the transmission 4. By referring to the torque map, the ESP controller 7 specifies a specified range according to the vehicle speed smoothed value VSf and the gear stage formed by the transmission 4, and outputs the torque smoothed value Trqf within the specified specified range. It is determined whether or not there is.

  That is, the ESP controller 7 specifies the output torque Trqh by referring to the torque map, specifies the range of the upper and lower Trqw of the specified output torque Trqh as the specified range, and outputs the output torque annealing value within the specified specified range. It is determined whether or not there is Trqf. Trqw may be an adaptive value that changes according to the driving state of the vehicle, or may be a constant adaptive value.

  Specifically, the ESP controller 7 determines that the vehicle 1 is traveling on a flat traveling surface on condition that the output torque smoothed value Trqf is within the range of the upper and lower Trqw of the output torque Trqh. ing. That is, the ESP controller 7 determines that the vehicle 1 is traveling on a flat traveling surface on condition that the following formula (8) is satisfied.

Trqh−Trqw <Trqf <Trqh + Trqw (8)

  Note that the torque map only needs to represent the relationship between the vehicle speed and the output torque Trqh for each gear stage formed in the transmission 4, and a polynomial function that linearly approximates the relationship between the output torque Trqh and the vehicle speed, A nonlinear function such as a table may be used.

  In the present embodiment, the ESP controller 7 determines whether or not the detected value of the rudder angle sensor 13 is within a predetermined range. Here, the ESP controller 7 is configured to remove unnecessary vibration components of the steering angle SA detected by the steering angle sensor 13.

  As an example, the ESP controller 7 is configured to sequentially calculate the steering angle smoothed value SAf obtained by smoothing the steering angle SA according to the following formula (9). In Equation (9), the smoothing teaching is Ksaf, and the previous steering angle smoothing value is SAfo. Moreover, the annealing teacher Ksaf is a fitness value from 0 to 1.

SAf = KSaf × SAfo + (1−KSaf) × SA (9)

  The ESP controller 7 determines that the vehicle 1 is traveling straight if the steering angle smoothing value SAf is within the predetermined range, and the vehicle 1 is traveling straight if the steering angle smoothing value SAf is not within the predetermined range. It comes to judge that there is not.

  Further, the ESP controller 7 is configured to remove unnecessary vibration components of the acceleration Gi that is a detection value of the acceleration sensor 11. As an example, the ESP controller 7 sequentially calculates an acceleration smoothed value Gif obtained by accelerating the acceleration Gi according to the following formula (10). In Equation (10), let the smoothing teaching be Kgf and the previous acceleration smoothing value be Gifo. Moreover, the annealing teacher Kgf is a fitness value from 0 to 1.

Gif = Kgf × Gifo + (1−Kgf) × Gi (10)

  In the present embodiment, the ESP controller 7 determines that the vehicle 1 is traveling at a constant speed, determines that the traveling surface on which the vehicle 1 is traveling is flat, and the vehicle 1 travels straight. A correction amount calculation unit 34 that calculates a correction amount of the detection value of the acceleration sensor 11 (hereinafter also simply referred to as “sensor correction amount”) based on the detection value of the acceleration sensor 11 Configure.

  Specifically, the ESP controller 7 determines that the vehicle 1 is traveling at a constant speed, determines that the traveling surface on which the vehicle 1 is traveling is flat, and the vehicle 1 travels straight ahead. On the condition that it is determined that there is an offset, an offset value that makes the detection value of the acceleration sensor 11 zero, that is, a sensor correction amount is calculated.

  Specifically, the ESP controller 7 calculates the average value of the acceleration smoothed values Gif of a predetermined number of samples on the condition that the acceleration sensor correction amount of a predetermined number of samples is calculated in order to prevent a sudden change in the sensor correction amount. Gm and standard deviation Gs are calculated. Here, the predetermined number of samples is a fitness value.

  The ESP controller 7 is configured to update the sensor correction amount with the average value Gm on condition that the calculated average value Gm and standard deviation Gs are each equal to or less than a specified value. Here, each specified value is a conforming value.

  If it is not necessary to regulate the upper limit of the sensor correction amount, the ESP controller 7 may update the sensor correction amount with the average value Gm on condition that the calculated standard deviation Gs is equal to or less than a specified value. Good.

  In the present embodiment, the ESP controller 7 is configured to remove unnecessary vibration components of the sensor correction amount Gm. As an example, the ESP controller 7 sequentially calculates the sensor correction amount smoothed value Gerr obtained by smoothing the sensor correction amount Gm according to the following formula (11).

  In the equation (11), the annealing teaching is Kerr, and the previous sensor correction amount annealing value is Gerro. Moreover, the annealing teacher Kerr is a fitness value from 0 to 1. Further, the annealing process shown in Equation (11) is not necessarily required, and Gerr = Gm may be set.

Gerr = Kerr × Gero + (1−Kerr) × Gm (11)

  In the present embodiment, the ESP controller 7 constitutes a correction unit 35 that corrects the detection value of the acceleration sensor 11 based on the calculated sensor correction amount smoothed value Gerr. That is, the ESP controller 7 corrects the detected value of the acceleration sensor 11 by subtracting the sensor correction amount smoothed value Gerr from the detected value Gi of the acceleration sensor 11 and calculates the acceleration Gc (= Gi−Gerr) of the vehicle 1. It is supposed to be.

  As described above, the ESP controller 7 corrects the detection value of the acceleration sensor 11 based on the newly calculated sensor correction amount smoothing value Gerr when the average value Gm and the standard deviation Gs are each equal to or less than the specified value. When the average value Gm or the standard deviation Gs is not less than the specified value, the detection value of the acceleration sensor 11 is corrected based on the already calculated sensor correction amount smoothed value Gerr.

  The acceleration correction operation of the acceleration correction apparatus according to the embodiment of the present invention configured as described above will be described with reference to FIG. In addition, the acceleration correction operation described below starts periodically at predetermined time intervals.

  First, the ESP controller 7 executes a constant speed traveling determination process for determining whether or not the vehicle 1 is traveling at a constant speed (step S1). Next, the ESP controller 7 executes a flat surface traveling determination process for determining whether or not the traveling surface on which the vehicle 1 is traveling is flat (step S2).

  Next, the ESP controller 7 executes a straight traveling determination process for determining whether or not the vehicle 1 is traveling straight (step S3). In addition, the execution order of step S1 thru | or step S3 may be replaced, and at least one part of two or more steps may be performed in duplication.

  Next, the ESP controller 7 executes a correction amount calculation process for calculating a sensor correction amount (step S4). Thus, based on the calculated correction amount, the ESP controller 7 executes a correction process for correcting the detection value of the acceleration sensor 11 (step S5).

  Next, the constant speed running determination process (FIG. 5, step S1) will be described in detail with reference to FIG.

  First, the ESP controller 7 calculates the vehicle speed change amount VSd (step S11). Further, the ESP controller 7 calculates the acceleration change amount Gd (step S12). Here, the execution order of step S11 and step S12 may be changed, and at least a part may be executed in duplicate.

  Next, the ESP controller 7 calculates a vehicle speed change amount smoothed value VSdf obtained from the vehicle speed change amount VSd (step S13). Further, the ESP controller 7 calculates an acceleration change amount smoothed value Gdf obtained by multiplying the acceleration change amount Gd (step S14). Here, the execution order of step S13 and step S14 may be changed, and at least a part of them may be executed in an overlapping manner.

  Next, the ESP controller 7 determines whether or not the vehicle 1 is in a constant speed traveling state in which the vehicle 1 is traveling at a constant speed (step S15). Here, the ESP controller 7 determines that the absolute value of the vehicle speed change amount smoothing value VSdf is smaller than the first specified value and the acceleration change amount smoothed value Gdf is smaller than the second specified value. The vehicle 1 is determined to be in a constant speed running state, and the absolute value of the vehicle speed change smoothing value VSdf is not smaller than the first specified value, or the absolute value of the acceleration change smoothing value Gdf is the second specified value. If it is not smaller than the value, it is determined that the vehicle 1 is not in a constant speed traveling state.

  If it is determined in step S15 that the vehicle 1 is in the constant speed running state, the ESP controller 7 stores information indicating that the vehicle 1 is in the constant speed running state in a storage medium such as a RAM (step S16). ), The constant speed running determination process is terminated.

  On the other hand, when it is determined that the vehicle 1 is not in the constant speed running state, the ESP controller 7 stores information indicating that the vehicle 1 is not in the constant speed running state in a storage medium such as a RAM (step S17). The constant speed running determination process ends.

  Next, with reference to FIG. 7, the flat surface travel determination process (FIG. 5, step S2) will be described in detail.

  First, the ESP controller 7 calculates the vehicle speed VS based on the detection value of the vehicle speed sensor 12 (step S21). Next, the ESP controller 7 calculates a vehicle speed smoothed value VSf obtained by smoothing the vehicle speed VS (step S22).

  Next, the ESP controller 7 calculates an output torque smoothed value Trqf obtained by smoothing the output torque Trq of the engine 2 (step S23). Next, the ESP controller 7 refers to the torque map and specifies a specified range of output torque according to the shift speed formed in the transmission 4 and the vehicle speed smoothing value VSf (step S24).

  Next, the ESP controller 7 determines whether or not the traveling surface on which the vehicle 1 is traveling is flat, that is, whether or not the vehicle 1 is in a flat surface traveling state (step S25). Here, the ESP controller 7 determines that the vehicle 1 is in the flat surface running state when the output torque smoothing value Trqf is within the specified range specified in step S24, and the output torque smoothing is within the specified range. When there is no value Trqf, it is determined that the vehicle 1 is not in a flat surface traveling state.

  If it is determined in step S25 that the vehicle 1 is in a flat surface traveling state, the ESP controller 7 stores information indicating that the vehicle 1 is in a flat surface traveling state in a storage medium such as a RAM (step S26). ), The flat surface running determination process is terminated.

  On the other hand, when it is determined that the vehicle 1 is not in the flat surface traveling state, the ESP controller 7 stores information indicating that the vehicle 1 is not in the flat surface traveling state in a storage medium such as a RAM (step S27). The flat surface running determination process is terminated.

  Next, with reference to FIG. 8, the straight traveling determination process (FIG. 5, step S3) will be described in detail.

  First, the ESP controller 7 calculates a steering angle smoothing value SAf obtained by making the steering angle SA (step S31). Next, it is determined whether or not the vehicle 1 is in a straight traveling state in which the vehicle 1 is traveling straight (step S32).

  Here, the ESP controller 7 determines that the vehicle 1 is traveling straight if the steering angle smoothing value SAf is within the predetermined range, and if the steering angle smoothing value SAf is not within the predetermined range, the vehicle 1 It is determined that the vehicle is not going straight.

  If it is determined in step S32 that the vehicle 1 is in the straight traveling state, the ESP controller 7 stores information indicating that the vehicle 1 is in the straight traveling state in a storage medium such as a RAM (step S33). The straight traveling determination process is terminated.

  On the other hand, when it is determined that the vehicle 1 is not in the straight traveling state, the ESP controller 7 stores information indicating that the vehicle 1 is not in the straight traveling state in a storage medium such as a RAM (step S34), and travels straight. The determination process ends.

  Next, the correction amount calculation processing (FIG. 5, step S4) will be described in detail with reference to FIG.

  First, the ESP controller 7 calculates an acceleration smoothed value Gif obtained by accelerating the acceleration Gi (step S41). Next, the ESP controller 7 determines whether or not it is in a correction amount calculation permission state in which calculation of the sensor correction amount is permitted (step S42).

  Here, the ESP controller 7 stores information indicating that the vehicle 1 is in a constant speed traveling state, the vehicle 1 is in a flat surface traveling state, and the vehicle 1 is in a straight traveling state, such as a RAM. Is stored in the correction amount calculation permission state, the vehicle 1 is not in the constant speed traveling state, the vehicle 1 is not in the flat surface traveling state, or the vehicle 1 is in the straight traveling state. If the information indicating that the correction amount is not present is stored in a storage medium such as a RAM, it is determined that the correction amount calculation is not permitted.

  If it is determined in step S42 that the correction amount calculation is not permitted, the ESP controller 7 ends the correction amount calculation process. On the other hand, if it is determined that the correction amount calculation is permitted, the ESP controller 7 stores the acceleration smoothed value Gif in a storage medium such as a RAM (step S43).

  Next, the ESP controller 7 determines whether or not the acceleration smoothed value Gif of a predetermined number of samples has been stored (step S44). Here, if it is determined that the acceleration smoothed value Gif of the predetermined number of samples is not stored, the ESP controller 7 ends the correction amount calculation process.

  On the other hand, if it is determined that the acceleration smoothed value Gif of the predetermined number of samples has been stored, the ESP controller 7 calculates the average value Gm of the acceleration smoothed value Gif (step S45) and calculates the standard deviation Gs. (Step S46).

  Next, the ESP controller 7 determines whether or not it is in a correction amount update permission state in which updating of the sensor correction amount is permitted (step S47). Here, when the average value Gm calculated in step S45 and the standard deviation Gs calculated in step S46 are each equal to or less than the specified value, the ESP controller 7 determines that the correction amount update permission state is set, and the average value Gm Alternatively, when the standard deviation Gs is not less than the specified value, it is determined that the correction amount update permission state is not established.

  If it is determined in step S47 that the correction amount update permission state exists, the ESP controller 7 calculates and updates the sensor correction amount smoothing value Gerr (step S48), and ends the correction amount calculation processing. On the other hand, when it is determined that the correction amount update permission state is not set, the ESP controller 7 maintains the already calculated sensor correction amount smoothing value Gerr and ends the correction amount calculation processing.

  Next, the correction process (FIG. 5, step S5) will be described in detail with reference to FIG. In the correction process, the ESP controller 7 corrects the detection value of the acceleration sensor 11 by subtracting the sensor correction amount smoothed value Gerr from the detection value of the acceleration sensor 11 (step S51).

  Next, with reference to FIG. 11, the operation of the acceleration correction apparatus according to the embodiment of the present invention will be described.

  As described above, the acceleration correction apparatus according to the present embodiment includes an acceleration sensor during a period in which the vehicle 1 is in a constant speed traveling state, the vehicle 1 is in a flat surface traveling state, and the vehicle 1 is in a straight traveling state. The offset from zero of the detected value of 11 is set as the sensor correction amount, and the acceleration corrected by subtracting the correction amount from the detected value of the acceleration sensor 11 is set as the acceleration of the vehicle 1.

  FIG. 11 shows a situation in which the vehicle 1 is traveling at a constant speed in an environment where uphill roads, downhill roads, and flat roads are continuous. When the vehicle 1 is traveling at a constant speed, the acceleration in the traveling direction is ideally zero.

  Therefore, in a state where the vehicle 1 is traveling at a constant speed, the detected value of the acceleration sensor 11 is ideally zero on the flat roads 101 and 104, and the gradient component is on the downhill roads 100 and 103 and the uphill road 102. Thus, the detection value of the acceleration sensor 11 varies with respect to the acceleration of the vehicle 1.

  That is, when there is no error in the detection value of the acceleration sensor 11, the detection value of the acceleration sensor is ideally as indicated by the broken line 110. However, when the detected value of the acceleration sensor 11 includes an error, for example, as indicated by a solid line 111, the error is offset by the error.

  Therefore, in the acceleration correction device of the present embodiment, the detected value of the acceleration sensor 11 during the period in which the vehicle 1 is in the constant speed running state, the vehicle 1 is in the flat surface running state, and the vehicle 1 is in the straight running state. The offset from zero is taken as the correction amount.

  The output of the engine 2 required for the vehicle 1 to travel on a flat road at a constant speed is ideally determined uniquely with respect to the vehicle speed. When the vehicle 1 travels at a constant speed, the output of the engine 2 is higher on the uphill road than on the flat road, and the output of the engine 2 is lower on the downhill road than on the flat road.

  Therefore, the acceleration correction apparatus of the present embodiment measures in advance the output of the engine 2 necessary for the vehicle 1 to travel on a flat road at a constant speed, and the engine 2 during the period of traveling at a constant speed. By comparing the output and the output of the engine 2 measured in advance, it is determined that the vehicle is traveling on a flat road only when these outputs match.

  That is, in the acceleration correction device of the present embodiment, the output of the engine 2 is higher than the output of the engine 2 when the vehicle 1 is running on a flat surface during the period in which the vehicle 1 is traveling at a constant speed. When it is large, it is determined that the vehicle 1 is traveling on an uphill road, and when the output of the engine 2 is small, it is determined that the vehicle 1 is traveling on a downhill road.

  As described above, the acceleration correction apparatus of the present embodiment uses the average value of the detection values of the acceleration sensor 11 of a predetermined number of samples as the correction amount during the period when it is determined that the vehicle is traveling on a flat road at a constant speed. The offset amount from zero of the acceleration signal is corrected (cancelled) by subtracting the calculated correction amount from the detection value of the acceleration sensor 11.

  As described above, the acceleration correction apparatus according to the present embodiment sequentially performs the process of smoothing the detection value of the acceleration sensor 11 in order to remove unnecessary vibration components when the vehicle is traveling.

  Further, in the acceleration correction device of the present embodiment, the average value of the detected values of the acceleration sensor 11 after smoothing when the vehicle 1 is traveling on a flat road at a constant speed is used as the correction amount. By calculating the standard deviation of the values, that is, the variation of the acceleration signal, it is possible to monitor whether or not the correction amount is calculated from the varying acceleration signal.

  Furthermore, the acceleration correction apparatus according to the present embodiment compares the output of the engine 2 when the vehicle 1 is traveling with the output of the engine 2 measured in advance, so that the road in the front-rear direction of the vehicle Variations in the detection value of the acceleration sensor 11 due to the gradient can be taken into account.

  Therefore, the acceleration correction apparatus according to the present embodiment prevents unnecessary acceleration information from being used by removing unnecessary vibration of the detected value of the acceleration sensor 11 during running by the annealing process.

  In other words, the acceleration correction apparatus according to the present embodiment monitors variations, and when the variations are large, it is determined that the information is not reliable and is not used for correction.

  Therefore, the acceleration correction apparatus of the present embodiment does not use the displacement of the acceleration signal due to the road gradient as the correction amount by considering the road gradient in the vehicle longitudinal direction, so that a more accurate and stable value can be obtained. Can be calculated.

  As described above, since the acceleration correction apparatus according to the present embodiment has a function of monitoring the variation in the detection value of the acceleration sensor 11, the correction amount is calculated only when the variation in the detection value of the acceleration sensor 11 is small.

  That is, the acceleration correction apparatus according to the present embodiment determines that the information is stable and reliable if the variation in the detection value of the acceleration sensor 11 is small even in a short period. Since the acceleration correction apparatus according to the present embodiment monitors variations in the detection value of the acceleration sensor 11, the ESP controller 7 does not need to be continuously in the correction amount calculation permission state, and the correction amount calculation permission state. Therefore, it is only necessary to simply collect acceleration information for a certain period of time, so that the time taken to calculate the correction amount is shortened.

  As an example, the case where the acceleration correction apparatus of this Embodiment is applied with respect to the vehicle 1 which performs false start suppression control is demonstrated. During the period in which the erroneous start suppression control is executed, the output of the engine 2 is suppressed to a low level. Therefore, on an uphill with a large gradient, the output of the engine 2 is insufficient, and the vehicle 1 moves down in the direction of going down the hill. In order to prevent this slipping down, in the erroneous start suppression control, it is required to monitor the road gradient and perform control with a control amount corresponding to the road gradient.

  The acceleration sensor such as the acceleration sensor 11 may cause a drift error in its detection value due to product variations, quality variations, aging deterioration, attachment errors, and the like, and the control performance may be reduced. By applying this acceleration correction device, it is possible to detect a road gradient without an error, and to prevent the above-described sliding or the like.

  In addition, since the acceleration correction apparatus according to the present embodiment can be applied without depending on the vehicle specifications, even if the sensor constituting the acceleration sensor 11 and the specifications of the vehicle 1 are changed, the road gradient can be detected accurately. can do.

  Therefore, the acceleration correction apparatus according to the present embodiment can realize erroneous start suppression control that prevents the vehicle from sliding down, regardless of the road gradient, with respect to four-wheeled vehicles of all vehicle types and specifications. .

  As described above, according to the present embodiment, when it is determined that the vehicle 1 is traveling at a constant speed and it is determined that the traveling surface on which the vehicle 1 is traveling is flat, the acceleration sensor 11. The sensor correction amount is calculated based on the detected value, the standard deviation of the sensor correction amount is calculated, and the correction value of the detection value of the acceleration sensor is updated on condition that the calculated standard deviation is equal to or less than the specified value. .

  Therefore, in the present embodiment, when the detection value of the acceleration sensor 11 is ideally zero, the correction amount of the detection value of the acceleration sensor 11 is calculated, and there is no variation in the correction amount of the detection value of the acceleration sensor 11. In this case, since the sensor correction amount is updated, the correction accuracy for the detection value of the acceleration sensor 11 can be improved.

  In the present embodiment, the absolute value of the change amount of the detection value of the vehicle speed sensor 12 is smaller than the first specified value, and the absolute value of the change amount of the detection value of the acceleration sensor 11 is less than the second specified value. Since it is determined that the vehicle is traveling at a constant speed on the condition that the vehicle is small, it can be accurately determined whether or not the vehicle 1 is traveling at a constant speed.

  Further, in the present embodiment, the vehicle 1 travels on the condition that the output torque of the engine 2 is within a specified range corresponding to the detection value of the vehicle speed sensor 12 and the shift speed formed by the transmission 4. Therefore, it is possible to accurately determine whether or not the traveling surface on which the vehicle 1 is traveling is flat.

  Further, in the present embodiment, the sensor correction amount is calculated on the condition that the detection value of the rudder angle sensor 13 is within a predetermined range, so that the detection value of the acceleration sensor 11 is corrected with a more accurate correction amount. can do.

  In the present embodiment, the sensor correction amount is calculated on the condition that the detected value of the steering angle sensor 13 is within a predetermined range. However, the steering angle is calculated based on the condition for calculating the sensor correction amount. You may omit that the detection value of the sensor 13 exists in a predetermined range.

  In this case, step S3 in the acceleration correction operation shown in FIG. 5 is not executed, and it is determined in step S42 of the correction amount calculation process shown in FIG. 9 that the ESP controller 7 is in the correction amount calculation permission state. The condition excludes that the vehicle 1 is in a straight traveling state.

  Although the embodiments of the present invention have been disclosed above, it is obvious that those skilled in the art can make modifications without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the claims recited in the claims.

DESCRIPTION OF SYMBOLS 1 Vehicle 4 Transmission 11 Acceleration sensor 12 Vehicle speed sensor 13 Steering angle sensor 30 Torque detection part 31 Acceleration correction apparatus 32 Constant speed traveling determination part 33 Flat travel determination part 34 Correction amount calculation part 35 Correction part

Claims (4)

An acceleration correction device that corrects a detection value of an acceleration sensor that detects acceleration of a vehicle,
A constant speed traveling determination unit that determines whether or not the vehicle is traveling at a constant speed;
A flat travel determination unit for determining whether or not the traveling surface on which the vehicle is traveling is flat;
When it is determined by the constant speed traveling determination unit that the vehicle is traveling at a constant speed, and the flat traveling determination unit determines that the traveling surface on which the vehicle is traveling is flat, A correction amount calculation unit that calculates a correction amount of the detection value of the acceleration sensor based on the detection value of the acceleration sensor;
A correction unit that corrects the detection value of the acceleration sensor based on the correction amount calculated by the correction amount calculation unit;
The correction amount calculation unit calculates a standard deviation of a correction amount of the detection value of the acceleration sensor, and updates the correction amount of the detection value of the acceleration sensor on condition that the calculated standard deviation is equal to or less than a specified value. Acceleration correction device. A vehicle speed sensor for detecting the speed of the vehicle is provided;
The constant speed travel determination unit has an absolute value of a change amount of the detection value of the vehicle speed sensor smaller than a first specified value, and an absolute value of the change amount of the detection value of the acceleration sensor is smaller than a second specified value. The acceleration correction apparatus according to claim 1, wherein it is determined that the vehicle is traveling at a constant speed on condition that the vehicle is small. A torque detector for detecting an output torque of a driving source of the vehicle;
A transmission for shifting the power output from the drive source;
A vehicle speed sensor for detecting the speed of the vehicle,
The flat travel determination unit is configured to travel the vehicle on the condition that the detection value of the torque detection unit is within a specified range corresponding to a detection value of the vehicle speed sensor and a shift speed formed by the transmission. The acceleration correction apparatus according to claim 1, wherein the running surface is determined to be flat. A steering angle sensor for detecting a steering angle of the vehicle is further provided;
The correction amount calculation unit calculates the correction amount of the detection value of the acceleration sensor on the condition that the detection value of the steering angle sensor is within a predetermined range. The acceleration correction apparatus according to claim.

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