Acceleration calculation device

Abstract

To provide an acceleration calculation device capable of continuing to calculate estimated acceleration of a vehicle even when either an acceleration sensor or a wheel speed sensor is abnormal.SOLUTION: When the acceleration sensor 300 and the wheel speed sensor 400 are both normal (S210: NO), the acceleration calculation device calculates the estimated acceleration eA using the first acceleration AG and the second acceleration AW. When the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal (S210: YES), the acceleration calculation device calculates the estimated acceleration eA using only the first acceleration AG out of the first acceleration AG and the second acceleration AW. When the acceleration sensor 300 is abnormal and the wheel speed sensor 400 is normal (S220: NO), the acceleration calculation device calculates the estimated acceleration eA using only the second acceleration AW out of the first acceleration AG and the second acceleration AW.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an acceleration calculation device. [Background technology]

[0002] Patent Document 1 discloses a calculation device that includes a first means for calculating an estimated vehicle body acceleration based on wheel speeds calculated from wheel speed sensors, and a second means for calculating an estimated acceleration calculated from an acceleration sensor. The calculation device selectively uses the first means and the second means depending on the vehicle's running conditions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-004575 Summary of the Invention [Problem to be solved by the invention]

[0004] There is room for further study on a method for calculating an estimated acceleration of the vehicle when either the wheel speed sensor or the acceleration sensor becomes abnormal. [Means for solving the problem]

[0005] The acceleration calculation device is an acceleration calculation device provided in a vehicle. The vehicle includes an acceleration sensor that detects a first acceleration acting in the longitudinal direction of the vehicle and a plurality of wheel speed sensors that detect wheel speeds, which are rotational speeds of wheels provided on the vehicle. The acceleration calculation device acquires the first acceleration from the acceleration sensor. The acceleration calculation device calculates a second acceleration from a rate of change of the wheel speeds acquired from the plurality of wheel speed sensors. When both the acceleration sensor and the wheel speed sensor are normal, the acceleration calculation device calculates an estimated acceleration of the vehicle using the first acceleration and the second acceleration. When the acceleration sensor is normal and the wheel speed sensor is abnormal, the acceleration calculation device calculates the estimated acceleration using only the first acceleration of the first acceleration and the second acceleration. When the acceleration sensor is abnormal and the wheel speed sensor is normal, the acceleration calculation device calculates the estimated acceleration using only the second acceleration of the first acceleration and the second acceleration. [Effects of the Invention]

[0006] The acceleration calculation device can continue to calculate the estimated acceleration of the vehicle even if an abnormality occurs in either the acceleration sensor or the wheel speed sensor. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a functional block diagram showing the configuration of a vehicle motion manager according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram showing the calculation process of the estimated acceleration executed by the acceleration calculation device of the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the flow of the process of calculating the estimated acceleration executed by the acceleration calculation device of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) An acceleration calculation device 110 according to the first embodiment will be described below with reference to Figures 1 and 2. In the following description, "front," "rear," "right," and "left" refer to the "front," "rear," "right," and "left" directions as seen by a passenger facing forward in the vehicle. The left-right direction coincides with the vehicle width direction.

[0009] <Overall configuration of vehicle 10> 1, a vehicle 10 includes a motion manager 100, a driving assistance ECU (Electronic Control Unit) 200, an acceleration sensor 300, a plurality of wheel speed sensors 400, a drive unit 500, and a braking unit 600. The ECU includes a CPU and a memory that stores control programs and data. The ECU performs various control-related processes by having the CPU execute the programs stored in the memory.

[0010] <Exercise Manager 100> The motion manager 100 controls the entire vehicle 10. The motion manager 100 is configured with a processing circuit. For example, the processing circuit includes an execution device and a storage device. The storage device stores various control programs executed by the execution device. The processing circuit realizes various processes by the execution device executing the control programs. The motion manager 100 is configured to be able to communicate with the driving assistance ECU 200. The motion manager 100 is configured to be able to communicate with the acceleration sensor 300 and multiple wheel speed sensors 400. The motion manager 100 is configured to be able to communicate with the drive unit 500 and the braking unit 600. The configuration of the motion manager 100 will be described later.

[0011] <Driving assistance ECU 200> The driving assistance ECU 200 realizes functions related to driving assistance of the vehicle 10. The driving assistance ECU 200 is configured by a processing circuit. The driving assistance ECU 200 stores a plurality of applications. Each application stored in the driving assistance ECU 200 outputs an exercise request to the exercise manager 100. The applications stored in the driving assistance ECU 200 include a first assistance application 210, a second assistance application 220, a third assistance application 230, and a fourth assistance application 240.

[0012] The first support application 210 is application software that realizes, as a driving support function, ACC (Adaptive Cruise Control) that causes the vehicle 10 to follow a preceding vehicle while maintaining a constant distance from the preceding vehicle. The first support application 210 outputs, as an exercise request, a required acceleration rACC, which is the acceleration of the vehicle 10 required to realize ACC, to the exercise manager 100.

[0013] The second support application 220 is application software that realizes an ASL (Auto Speed ​​Limiter) as a driving support function that limits the upper limit of the speed of the vehicle 10 to match the speed displayed on a road sign. The second support application 220 outputs, as an exercise request, a required acceleration rASL, which is the acceleration of the vehicle 10 required to realize the ASL, to the exercise manager 100.

[0014] The third support application 230 is application software that realizes a PCS (Pre-Crash Safety) function related to driving support, which warns the driver of the vehicle 10 and performs emergency braking of the vehicle 10 when there is a possibility that the vehicle 10 will rear-end a preceding vehicle. The third support application 230 outputs, as an exercise request, a required acceleration rPCS, which is the acceleration of the vehicle 10 required to realize the PCS, to the exercise manager 100.

[0015] The fourth support application 240 is application software that realizes an automatic driving function that causes the vehicle 10 to drive autonomously without driver operation as a driving support function. The fourth support application 240 outputs, as an exercise request, a required acceleration rAD, which is the acceleration of the vehicle 10 required to realize the automatic driving function, to the exercise manager 100.

[0016] <Acceleration Sensor 300 and Wheel Speed ​​Sensor 400> The acceleration sensor 300 is configured to be able to detect a first acceleration AG acting in the longitudinal direction of the vehicle 10. The acceleration sensor 300 outputs the detected first acceleration AG to the exercise manager 100.

[0017] The multiple wheel speed sensors 400 are configured to be able to detect wheel speeds RS, which are the rotational speeds of wheels equipped on the vehicle 10. The vehicle 10 is equipped with a first wheel speed sensor 410, a second wheel speed sensor 420, a third wheel speed sensor 430, and a fourth wheel speed sensor 440 as the multiple wheel speed sensors 400. The first wheel speed sensor 410 detects a first wheel speed RS_1, which is the wheel speed RS of the right front wheel of the vehicle 10. The first wheel speed sensor 410 outputs the first wheel speed RS_1 to the motion manager 100. The second wheel speed sensor 420 detects a second wheel speed RS_2, which is the wheel speed RS of the left front wheel of the vehicle 10. The second wheel speed sensor 420 outputs the second wheel speed RS_2 to the motion manager 100. The third wheel speed sensor 430 detects a third wheel speed RS_3, which is the wheel speed of the right rear wheel of the vehicle 10. The third wheel speed sensor 430 outputs the third wheel speed RS_3 to the motion manager 100. The fourth wheel speed sensor 440 detects a fourth wheel speed RS_4, which is the wheel speed RS of the left rear wheel of the vehicle 10. The fourth wheel speed sensor 440 outputs the fourth wheel speed RS_4 to the motion manager 100.

[0018] <Drive unit 500 and brake unit 600> The drive unit 500 and the braking unit 600 are actuators of the vehicle 10. The drive unit 500 includes a drive device 510 of the vehicle 10 and a drive ECU 520. The drive device 510 of the vehicle 10 is, for example, an engine. The drive device 510 of the vehicle 10 may also be a motor generator. The drive ECU 520 is a processing circuit that controls the drive device 510. The drive ECU 520 controls the drive device 510 of the vehicle 10 in accordance with instruction information K input from the motion manager 100.

[0019] The braking unit 600 includes a braking device 610 for each wheel and a braking ECU 620. The braking device 610 is, for example, a disc brake. The braking ECU 620 is a processing circuit that controls each braking device 610. The braking ECU 620 controls each braking device 610 in accordance with instruction information K input from the motion manager 100.

[0020] <Configuration of Exercise Manager 100> The motion manager 100 receives a plurality of motion requests from the driving assistance ECU 200. The motion manager 100 controls the vehicle 10 by arbitrating the plurality of motion requests. The motion manager 100 is composed of an acceleration calculation device 110, an arbitration ECU 120, a calculation ECU 130, and a distribution ECU 140.

[0021] The acceleration calculation device 110 calculates an estimated acceleration eA of the vehicle 10 based on the first acceleration AG or the wheel speed RS. The calculation process of the estimated acceleration eA performed by the acceleration calculation device 110 will be described later. The acceleration calculation device 110 outputs the estimated acceleration eA to the calculation ECU 130.

[0022] The arbitration ECU 120 arbitrates multiple motion requests. The multiple motion requests are a requested acceleration rACC, a requested acceleration rASL, a requested acceleration rPCS, and a requested acceleration rAD input from the driving assistance ECU 200. When only one motion request is input from the driving assistance ECU 200, the arbitration ECU 120 outputs the requested acceleration rA of the motion request as the arbitration result ARB to the calculation ECU 130. For example, when the only motion request input to the arbitration ECU 120 is the requested acceleration rACC input from the first assistance application 210, the arbitration ECU 120 outputs the requested acceleration rACC as the arbitration result ARB to the calculation ECU 130. When multiple motion requests are input from the driving assistance ECU 200, the arbitration ECU 120 selects the motion request with the smaller requested acceleration rA as the arbitration result ARB. For example, if multiple required accelerations rA, which are motion requests, are all negative values, the motion request with the largest absolute value is selected as the arbitration result ARB. In this way, the arbitration ECU 120 arbitrates the multiple motion requests. For example, if the required acceleration rASL is smaller than the required acceleration rACC, the arbitration ECU 120 selects the required acceleration rASL as the arbitration result ARB. The arbitration method performed by the arbitration ECU 120 is not limited to the above example. It is sufficient that arbitration rules are defined for the arbitration ECU 120 so that an appropriate arbitration result ARB is obtained. The arbitration ECU 120 outputs the required acceleration rASL, which is the arbitration result ARB, to the calculation ECU 130.

[0023] The calculation ECU 130 receives an input of the estimated acceleration eA from the acceleration calculation device 110. The calculation ECU 130 receives an input of the arbitration result ARB from the arbitration ECU 120. The calculation ECU 130 calculates a required acceleration F, which is an acceleration required to make the acceleration of the vehicle 10 equal to the required acceleration rA. For example, the calculation ECU 130 calculates the required acceleration F based on the difference between the estimated acceleration eA and the arbitration result ARB. The method of calculating the required acceleration F performed by the calculation ECU 130 is not limited to the above example. It is sufficient that the calculation ECU 130 has a rule for the calculation method so that an appropriate required acceleration F can be obtained. The calculation ECU 130 outputs the required acceleration F to the distribution ECU 140. If the calculation ECU 130 does not receive the input of the estimated acceleration eA from the acceleration calculation device 110, the calculation ECU 130 does not calculate the required acceleration F or output the required acceleration F to the distribution ECU 140.

[0024] The distribution ECU 140 controls the drive unit 500 and the braking unit 600 based on the required acceleration F input from the calculation ECU 130. That is, the distribution ECU 140 outputs, to each actuator, command information K required for the vehicle 10 to achieve the required acceleration F. As a result, the vehicle 10 executes a function related to the driving assistance of the vehicle 10 instructed by the driving assistance ECU 200. If the required acceleration F is not input from the calculation ECU 130, the distribution ECU 140 does not output the command information K to each actuator. That is, if the estimated acceleration eA is not input from the acceleration calculation device 110 to the arbitration ECU 120, the vehicle 10 does not execute a function related to the driving assistance.

[0025] <Calculation Process of Estimated Acceleration eA Executed by Acceleration Calculation Device 110> 2 is a functional block diagram showing the calculation process of estimated acceleration eA executed by acceleration calculation device 110 in the first embodiment. As shown in Fig. 2, acceleration calculation device 110 includes first determination unit 111, second determination unit 112, first acquisition unit 113, second acquisition unit 114, first processing unit 115, second processing unit 116, third processing unit 117, fourth processing unit 118, and calculation unit 119.

[0026] The first determination unit 111 determines whether or not there is an abnormality in the acceleration sensor 300. For example, when the rate of change of the first acceleration AG input to the acceleration calculation device 110 exceeds a predetermined threshold, the first determination unit 111 determines that there is an abnormality in the acceleration sensor 300. For example, when the first acceleration AG is not input to the acceleration calculation device 110, the first determination unit 111 determines that there is an abnormality in the acceleration sensor 300. The first determination unit 111 outputs the determination result to the calculation unit 119.

[0027] The second determination unit 112 determines whether or not there is an abnormality in each wheel speed sensor 400. For example, if the rate of change of the first wheel speed RS_1 exceeds a predetermined threshold, the second determination unit 112 determines that there is an abnormality in the first wheel speed sensor 410. For example, if the first wheel speed RS_1 is not input to the acceleration calculation device 110, the second determination unit 112 determines that there is an abnormality in the first wheel speed sensor 410. The second determination unit 112 similarly determines whether or not there is an abnormality in the other wheel speed sensors 400. If there is an abnormality in at least one of the first wheel speed sensor 410, the second wheel speed sensor 420, the third wheel speed sensor 430, and the fourth wheel speed sensor 440, the acceleration calculation device 110 determines that there is an abnormality in the wheel speed sensor 400. The second determination unit 112 outputs the determination result to the calculation unit 119.

[0028] The first acquisition unit 113 acquires the first acceleration AG from the acceleration sensor 300. The first acquisition unit 113 outputs the first acceleration AG to the first processing unit 115 and the third processing unit 117. The second acquisition unit 114 acquires a first wheel speed RS_1, a second wheel speed RS_2, a third wheel speed RS_3, and a fourth wheel speed RS_4. The second acquisition unit 114 selects a wheel speed RS for calculating the second acceleration AW from the plurality of wheel speeds RS. The second acquisition unit 114 calculates the second acceleration AW based on the selected wheel speed RS.

[0029] For example, the second acquisition unit 114 selects the second-largest wheel speed RS among the four wheel speeds RS as the wheel speed RS for calculating the second acceleration AW. If the second-largest wheel speed RS is the second wheel speed RS_2, the second acquisition unit 114 calculates the second acceleration AW based on the rate of change of the second wheel speed RS_2. For example, the second acquisition unit 114 selects the largest wheel speed RS among the wheel speeds RS of the driving wheels as the wheel speed RS for calculating the second acceleration AW. If the right front wheel and the left front wheel are driving wheels and the first wheel speed RS_1, which is the wheel speed RS of the right front wheel, is larger than the second wheel speed RS_2, which is the wheel speed RS of the left front wheel, the second acquisition unit 114 calculates the second acceleration AW based on the rate of change of the first wheel speed RS_1. The method of selecting the wheel speed RS executed by the second acquisition unit 114 is not limited to the above example. The second obtaining unit 114 only needs to determine a rule for the method of selecting the wheel speed RS so that an appropriate second acceleration AW can be obtained.

[0030] The second acquisition unit 114 outputs the second acceleration AW to the second processing unit 116 and the fourth processing unit 118. The first processing unit 115 receives the first acceleration AG from the first acquisition unit 113. The first processing unit 115 executes a first process in which high-pass filter HPF processing is performed on the first acceleration AG. As a result, the first processing unit 115 acquires the first acceleration AGHP after the first process. The first processing unit 115 outputs the first acceleration AGHP after the first process to the calculation unit 119.

[0031] The second processing unit 116 receives the second acceleration AW from the second acquisition unit 114. The second processing unit 116 executes second processing, which involves performing first low-pass filter LPF_1 processing on the second acceleration AW. As a result, the second processing unit 116 acquires the second acceleration AWLP1 after the second processing. The second processing unit 116 outputs the second acceleration AWLP1 after the second processing to the calculation unit 119. The cutoff frequency fc in the high-pass filter HPF processing executed by the first processing unit 115 and the cutoff frequency fc in the first low-pass filter LPF_1 processing executed by the second processing unit 116 are the same frequency.

[0032] The third processing unit 117 receives the first acceleration AG from the first acquisition unit 113. The third processing unit 117 executes a third process in which the first acceleration AG is subjected to low-pass filter LPF processing. As a result, the third processing unit 117 acquires the first acceleration AGLP after the third process. The third processing unit 117 outputs the first acceleration AGLP after the third process to the calculation unit 119.

[0033] The fourth processing unit 118 receives the second acceleration AW from the second acquisition unit 114. The fourth processing unit 118 executes fourth processing in which the second acceleration AW is subjected to processing by a second low-pass filter LPF_2 having a lower cutoff frequency fc than that of the first low-pass filter LPF_1. As a result, the fourth processing unit 118 acquires the second acceleration AWLP2 after the fourth processing. The fourth processing unit 118 outputs the second acceleration AWLP2 after the fourth processing to the calculation unit 119.

[0034] In the first embodiment, the acceleration calculation device 110 repeatedly executes the first process, the second process, the third process, and the fourth process at a predetermined cycle, regardless of whether or not there is an abnormality in the acceleration sensor 300 and whether or not there is an abnormality in the wheel speed sensor 400.

[0035] The calculation unit 119 receives an input of a determination result regarding the presence or absence of an abnormality in the acceleration sensor 300 from the first determination unit 111. The calculation unit 119 receives an input of a determination result regarding the presence or absence of an abnormality in the wheel speed sensor 400 from the second determination unit 112. The calculation unit 119 receives an input of the post-first processing first acceleration AGHP from the first processing unit 115. The calculation unit 119 receives an input of the post-second processing second acceleration AWLP1 from the second processing unit 116. The calculation unit 119 receives an input of the post-third processing first acceleration AGLP from the third processing unit 117. The calculation unit 119 receives an input of the post-fourth processing second acceleration AWLP2 from the fourth processing unit 118.

[0036] When both the acceleration sensor 300 and the wheel speed sensor 400 are normal, the calculation unit 119 adds the first processed first acceleration AGHP and the second processed second acceleration AWLP1 to obtain the superimposed acceleration AGHP+AWLP1. The cutoff frequency fc in the high-pass filter HPF processing is the same as the cutoff frequency fc in the first low-pass filter LPF_1 processing. Then, the acceleration calculation device 110 subjects the superimposed acceleration AGHP+AWLP1 to processing by the third low-pass filter LPF_3. As a result, the acceleration calculation device 110 obtains the processed superimposed acceleration AGHP+AWLP1_LP3. Then, the acceleration calculation device 110 outputs the processed superimposed acceleration AGHP+AWLP1_LP3 as the estimated acceleration eA of the vehicle 10.

[0037] If the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal, the calculation unit 119 outputs the post-third processing first acceleration AGLP as the estimated acceleration eA. If the acceleration sensor 300 is abnormal and the wheel speed sensor 400 is normal, the calculation unit 119 outputs the second acceleration AWLP2 after the fourth process as the estimated acceleration eA.

[0038] If both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal, the calculation unit 119 does not calculate the estimated acceleration eA. The calculation unit 119 outputs the estimated acceleration eA to the calculation ECU 130. If the calculation unit 119 does not calculate the estimated acceleration eA, it does not output a signal to the calculation ECU 130.

[0039] <Operation of the First Embodiment> Even if there is an abnormality in the wheel speed sensor 400, the acceleration calculation device 110 calculates the estimated acceleration eA using the first acceleration AG as long as there is no abnormality in the acceleration sensor 300. Even if there is an abnormality in the acceleration sensor 300, the acceleration calculation device 110 calculates the estimated acceleration eA using the second acceleration AW as long as there is no abnormality in the wheel speed sensor 400.

[0040] <Effects of the first embodiment> (1-1) The acceleration calculation device 110 can continue to calculate the estimated acceleration eA of the vehicle 10 even if either the acceleration sensor 300 or the wheel speed sensor 400 has an abnormality.

[0041] (1-2) The first acceleration AG acquired by the first processing unit 115 from the acceleration sensor 300 is likely to contain low-frequency noise components due to the gradient of the road surface and the inclination of the acceleration sensor 300. The second acceleration AW calculated by the second processing unit 116 from the rate of change of the wheel speed RS is likely to contain high-frequency noise components due to the influence of bumps and seams on the road surface.

[0042] When both the acceleration sensor 300 and the wheel speed sensor 400 are normal, the acceleration calculation device 110 calculates the estimated acceleration eA of the vehicle 10 based on the post-first processing first acceleration AGHP and the post-second processing second acceleration AWLP1. The post-first processing first acceleration AGHP is the first acceleration AG in which low-frequency noise components have been reduced by high-pass filter HPF processing. The post-second processing second acceleration AWLP1 is the second acceleration AW in which high-frequency noise components have been reduced by first low-pass filter LPF_1 processing. Therefore, when both the acceleration sensor 300 and the wheel speed sensor 400 are normal, the acceleration calculation device 110 can calculate a more appropriate estimated acceleration eA with fewer noise components.

[0043] (1-3) The first process may remove low-frequency noise components as well as low-frequency acceleration components from the first acceleration AG. When the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal, the acceleration calculation device 110 executes a third process in which the first acceleration AG is subjected to low-pass filter LPF processing. After the third process, the first acceleration AGLP includes low-frequency acceleration components in the first acceleration AG. The acceleration calculation device 110 can continue to output the estimated acceleration eA including low-frequency acceleration components even when the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal.

[0044] (1-4) The second-processed second acceleration AWLP1 is more affected by noise components derived from the second-processed second acceleration AWLP1 than the estimated acceleration eA calculated based on the first-processed first acceleration AGHP and the second-processed second acceleration AWLP1. Reducing the cutoff frequency fc in the low-pass filter processing allows noise components in a wider frequency band to be removed from the second acceleration AW. Therefore, the fourth-processed second acceleration AWLP2, which has been subjected to the second low-pass filter LPF_2 processing, which has a lower cutoff frequency fc than the first low-pass filter LPF_1 processing, has fewer noise components than the second-processed second acceleration AWLP1. When the acceleration sensor 300 is abnormal and the wheel speed sensor 400 is normal, the acceleration calculation device 110 can continue to output a more appropriate estimated acceleration eA by reducing the noise components included in the second acceleration AW used to calculate the estimated acceleration eA.

[0045] (1-5) The acceleration calculation device 110 executes all of the first process, the second process, the third process, and the fourth process, regardless of whether there is an abnormality in the acceleration sensor 300 or the wheel speed sensor 400. As a result, when an abnormality occurs in either the acceleration sensor 300 or the wheel speed sensor 400, the acceleration calculation device 110 can immediately calculate the estimated acceleration eA of the vehicle 10 based on the output of the sensor that is not experiencing an abnormality.

[0046] (1-6) If both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal, the acceleration calculation device 110 does not calculate the estimated acceleration eA. If both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal, the first acceleration AG and the second acceleration AW, which are necessary for the acceleration calculation device 110 to calculate the estimated acceleration eA, will both be inaccurate values. If both the first acceleration AG and the second acceleration AW are inaccurate values, the estimated acceleration eA calculated by the acceleration calculation device 110 based on the first acceleration AG or the second acceleration AW will also be inaccurate. Therefore, if both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal, the acceleration calculation device 110 does not calculate the estimated acceleration eA. This prevents the acceleration calculation device 110 from calculating an inaccurate estimated acceleration eA.

[0047] (1-7) If an abnormality occurs in one or more of the multiple wheel speed sensors 400, an inappropriate second acceleration AW may be calculated. The acceleration calculation device 110 determines that an abnormality has occurred in the wheel speed sensor 400 if an abnormality occurs in one or more wheel speed sensors 400. If the acceleration calculation device 110 determines that an abnormality has occurred in the wheel speed sensor 400, the acceleration calculation device 110 calculates the estimated acceleration eA using only the first acceleration AG of the first acceleration AG and the second acceleration AW. This allows the acceleration calculation device 110 to calculate the estimated acceleration eA of the vehicle 10 without using the inappropriate second acceleration AW.

[0048] (Second embodiment) An acceleration calculation device 110 according to the second embodiment will be described below with reference to Fig. 3. The second embodiment will be described mainly focusing on the differences from the first embodiment.

[0049] 3 is a flowchart showing the flow of calculation of the estimated acceleration eA by the acceleration calculation device 110 according to the second embodiment. The acceleration calculation device 110 repeatedly calculates the estimated acceleration eA at a predetermined cycle.

[0050] 3, when this series of processes starts, in step S200, acceleration calculation device 110 acquires whether or not there is an abnormality in acceleration sensor 300. In the process of step S200, if acceleration calculation device 110 determines that there is no abnormality in acceleration sensor 300 (step S200: NO), that is, if acceleration sensor 300 is normal, it proceeds to the process of step S210.

[0051] <When both the acceleration sensor 300 and the wheel speed sensor 400 are normal> In step S210, the acceleration calculation device 110 acquires whether or not there is an abnormality in the wheel speed sensor 400. In step S210, if the acceleration calculation device 110 determines that the wheel speed sensor 400 is not abnormal (step S210: NO), that is, if both the acceleration sensor 300 and the wheel speed sensor 400 are normal, the acceleration calculation device 110 proceeds to step S231.

[0052] In step S231, the acceleration calculation device 110 acquires a first acceleration AG from the acceleration sensor 300. Then, the acceleration calculation device 110 executes a first process in which high-pass filter HPF processing is performed on the first acceleration AG. As a result, the acceleration calculation device 110 acquires a first acceleration AGHP after the first process. Then, the process proceeds to step S233.

[0053] In step S233, the acceleration calculation device 110 selects a wheel speed RS for calculating the second acceleration AW from the plurality of wheel speeds RS, and calculates the second acceleration AW based on the selected wheel speed RS.

[0054] For example, the acceleration calculation device 110 selects the second-largest wheel speed RS among the four wheel speeds RS as the wheel speed RS for calculating the second acceleration AW. If the second-largest wheel speed RS is the second wheel speed RS_2, the acceleration calculation device 110 calculates the second acceleration AW based on the rate of change of the second wheel speed RS_2. For example, the acceleration calculation device 110 selects the largest wheel speed RS among the wheel speeds RS of the driving wheels as the wheel speed RS for calculating the second acceleration AW. If the right front wheel and the left front wheel are driving wheels and the first wheel speed RS_1, which is the wheel speed RS of the right front wheel, is larger than the second wheel speed RS_2, which is the wheel speed RS of the left front wheel, the acceleration calculation device 110 calculates the second acceleration AW based on the rate of change of the first wheel speed RS_1. The method of selecting the wheel speed RS executed by the acceleration calculation device 110 is not limited to the above example. It is sufficient that the acceleration calculation device 110 determines a rule for the method of selecting the wheel speed RS so as to obtain an appropriate second acceleration AW.

[0055] After calculating the second acceleration AW, the acceleration calculation device 110 executes a second process in which the second acceleration AW is subjected to a first low-pass filter LPF_1 process. As a result, the acceleration calculation device 110 acquires a second acceleration AWLP1 after the second process. The cutoff frequency fc in the high-pass filter HPF process and the cutoff frequency fc in the first low-pass filter LPF_1 process are the same frequency. Then, the process proceeds to step S235.

[0056] In step S235, the acceleration calculation device 110 acquires a superimposed acceleration AGHP+AWLP1 by adding the first processed first acceleration AGHP and the second processed second acceleration AWLP1. Then, the acceleration calculation device 110 performs processing by the third low-pass filter LPF_3 on the superimposed acceleration AGHP+AWLP1. As a result, the acceleration calculation device 110 acquires a processed superimposed acceleration AGHP+AWLP1_LP3. Then, the acceleration calculation device 110 outputs the processed superimposed acceleration AGHP+AWLP1_LP3 as the estimated acceleration eA of the vehicle 10. Then, the processing proceeds to step S300.

[0057] In step S300, the acceleration calculation device 110 outputs the estimated acceleration eA to the calculation ECU 130. After that, this series of processes ends. <When the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal> If the wheel speed sensor 400 is abnormal in step S210 (step S210: YES), that is, if the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal, the process proceeds to step S241.

[0058] In step S241, the acceleration calculation device 110 acquires the first acceleration AG from the acceleration sensor 300. Thereafter, the acceleration calculation device 110 executes a third process in which low-pass filter LPF processing is performed on the first acceleration AG. As a result, the acceleration calculation device 110 acquires the first acceleration AGLP after the third process. Then, the acceleration calculation device 110 outputs the first acceleration AGLP after the third process as the estimated acceleration eA of the vehicle 10. Thereafter, the process proceeds to step S300.

[0059] In step S300, the acceleration calculation device 110 outputs the estimated acceleration eA to the calculation ECU 130. Thereafter, the acceleration calculation device 110 ends this series of processes. <When the acceleration sensor 300 is abnormal and the wheel speed sensor 400 is normal> In step S200, if an abnormality exists in acceleration sensor 300 (step S200: YES), the process proceeds to step S220.

[0060] In step S220, if there is no abnormality in wheel speed sensor 400 (step S210: NO), that is, if there is an abnormality in acceleration sensor 300 and wheel speed sensor 400 is normal, the process proceeds to step S251.

[0061] In step S251, the acceleration calculation device 110 selects a wheel speed RS for calculating the second acceleration AW from the multiple wheel speeds RS, as in step S233. The acceleration calculation device 110 calculates the second acceleration AW based on the selected wheel speed RS, as in step S233. Thereafter, the acceleration calculation device 110 executes a fourth process in which the second acceleration AW is subjected to a second low-pass filter LPF_2 process. As a result, the acceleration calculation device 110 acquires a post-fourth-processing second acceleration AWLP2. The second low-pass filter LPF_2 has a lower cutoff frequency fc than the first low-pass filter LPF_1. The acceleration calculation device 110 outputs the post-fourth-processing second acceleration AWLP2 as the estimated acceleration eA of the vehicle 10. Then, the process proceeds to step S300.

[0062] In step S300, the acceleration calculation device 110 outputs the estimated acceleration eA to the calculation ECU 130. Thereafter, the acceleration calculation device 110 ends this series of processes. <When both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal> In step S220, if there is an abnormality in the wheel speed sensor 400 (step S220: YES), that is, if both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal, the acceleration calculation device 110 ends this series of processes without calculating the estimated acceleration eA.

[0063] <Operation of the Second Embodiment> If both the acceleration sensor 300 and the wheel speed sensor 400 are normal (S210: NO), the acceleration calculation device 110 calculates the estimated acceleration eA of the vehicle 10 using the first acceleration AG and the second acceleration AW. If the acceleration sensor 300 is normal and the wheel speed sensor 400 is abnormal (S210: YES), the acceleration calculation device 110 calculates the estimated acceleration eA using only the first acceleration AG of the first acceleration AG and the second acceleration AW. If the acceleration sensor 300 is abnormal and the wheel speed sensor 400 is normal (S220: NO), the acceleration calculation device 110 calculates the estimated acceleration eA using only the second acceleration AW of the first acceleration AG and the second acceleration AW. If both the acceleration sensor 300 and the wheel speed sensor 400 are abnormal (S220: YES), the acceleration calculation device 110 does not calculate the estimated acceleration eA of the vehicle 10.

[0064] <Effects of the second embodiment> (2-1) The acceleration calculation device 110 changes the process for calculating the estimated acceleration eA depending on whether or not there is an abnormality in the acceleration sensor 300 and the wheel speed sensor 400. This allows the acceleration calculation device 110 to reduce the load on the processing circuit for calculating the estimated acceleration eA.

[0065] <Example of change> Common modifiable elements of the above embodiments include the following: The following modifications can be implemented in combination with each other within the scope of technical compatibility.

[0066] The acceleration calculation device 110 may change the criteria for determining that the wheel speed sensor 400 is abnormal, as long as it can properly calculate the estimated acceleration eA. For example, the acceleration calculation device 110 may determine that the wheel speed sensor 400 is abnormal if two or more of the first wheel speed sensor 410, the second wheel speed sensor 420, the third wheel speed sensor 430, and the fourth wheel speed sensor 440 are abnormal. For example, the acceleration calculation device 110 may determine that the wheel speed sensor 400 is abnormal if three or more of the first wheel speed sensor 410, the second wheel speed sensor 420, the third wheel speed sensor 430, and the fourth wheel speed sensor 440 are abnormal. The acceleration calculation device 110 may determine that the wheel speed sensor 400 is abnormal if the wheel speed sensor 400 provided on the drive wheel is abnormal. For example, if the right front wheel and the left front wheel are drive wheels, the acceleration calculation device 110 may determine that there is an abnormality in the wheel speed sensor 400 if there is an abnormality in either the first wheel speed sensor 410 or the second wheel speed sensor 420 provided on the drive wheels. [Explanation of symbols]

[0067] AG...first acceleration, AGHP...first acceleration after first processing, AGLP...first acceleration after third processing, AW...second acceleration, AWLP1...second acceleration after second processing, AWLP2...second acceleration after fourth processing, eA...estimated acceleration, fc...cutoff frequency, RS...wheel speed, 10...vehicle, 110...acceleration calculation device, 300...acceleration sensor, 400...wheel speed sensor, 410...first wheel speed sensor, 420...second wheel speed sensor, 430...third wheel speed sensor, 440...fourth wheel speed sensor

Claims

1. A vehicle acceleration calculation device, the vehicle includes an acceleration sensor that detects a first acceleration acting in a longitudinal direction of the vehicle, and a plurality of wheel speed sensors that detect wheel speeds that are rotational speeds of wheels provided on the vehicle; acquiring the first acceleration from the acceleration sensor; calculating a second acceleration from the rate of change of the wheel speeds acquired from the plurality of wheel speed sensors; When both the acceleration sensor and the wheel speed sensor are normal, an estimated acceleration of the vehicle is calculated using the first acceleration and the second acceleration; When the acceleration sensor is normal and the wheel speed sensor is abnormal, the estimated acceleration is calculated using only the first acceleration of the first acceleration and the second acceleration; When the acceleration sensor is abnormal and the wheel speed sensor is normal, the estimated acceleration is calculated using only the second acceleration of the first acceleration and the second acceleration. Acceleration calculation device.

2. If both the acceleration sensor and the wheel speed sensor are normal, a first process is performed in which a high-pass filter process is applied to the first acceleration to obtain a first-processed first acceleration, and a second process is performed in which a first low-pass filter process is applied to the second acceleration to obtain a second-processed second acceleration, and the estimated acceleration is calculated based on the first-processed first acceleration and the second-processed second acceleration; When the acceleration sensor is normal and the wheel speed sensor is abnormal, a third process is executed in which a low-pass filter process is performed on the first acceleration to obtain a third-processed first acceleration, and the third-processed first acceleration is output as the estimated acceleration. When the acceleration sensor is abnormal and the wheel speed sensor is normal, a fourth process is executed in which a second low-pass filter process having a cutoff frequency smaller than that of the first low-pass filter process is performed on the second acceleration to obtain a fourth-processed second acceleration, and the fourth-processed second acceleration is output as the estimated acceleration. The acceleration calculation device according to claim 1 .

3. Regardless of whether or not there is an abnormality in the acceleration sensor and whether or not there is an abnormality in the wheel speed sensor, a first process of performing high-pass filtering on the first acceleration to obtain a first-processed first acceleration; a second process of performing a first low-pass filter process on the second acceleration to obtain a second-processed second acceleration; a third process of performing a low-pass filter process on the first acceleration to obtain a third-processed first acceleration; and a fourth process of performing a second low-pass filter process on the second acceleration, the second low-pass filter process having a cutoff frequency lower than that of the first low-pass filter process, to obtain a fourth-processed second acceleration. When both the acceleration sensor and the wheel speed sensor are normal, the estimated acceleration is calculated based on the first acceleration after the first processing and the second acceleration after the second processing; When the acceleration sensor is normal and the wheel speed sensor is abnormal, the first acceleration after the third processing is output as the estimated acceleration; If the acceleration sensor is abnormal and the wheel speed sensor is normal, the second acceleration after the fourth process is output as the estimated acceleration. The acceleration calculation device according to claim 1 .

4. If both the acceleration sensor and the wheel speed sensor are abnormal, the estimated acceleration is not calculated. The acceleration calculation device according to any one of claims 1 to 3.

5. The vehicle includes the plurality of wheel speed sensors. a first wheel speed sensor for acquiring a rotation speed of a right front wheel of the vehicle; a second wheel speed sensor for acquiring a rotation speed of a left front wheel of the vehicle; a third wheel speed sensor for acquiring a rotation speed of a right rear wheel of the vehicle; a fourth wheel speed sensor that acquires a rotation speed of a left rear wheel of the vehicle; Equipped with When an abnormality occurs in at least one of the first wheel speed sensor, the second wheel speed sensor, the third wheel speed sensor, and the fourth wheel speed sensor, it is determined that an abnormality occurs in the wheel speed sensor. The acceleration calculation device according to claim 4 .

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