JP2008061326A - Drive control unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the characteristic difference and deterioration of a power source for driving left and right wheels independently without providing any sensors for detecting the torque of the power source. <P>SOLUTION: A drive control unit for vehicles comprises: a straight drive state determination means S102 for determining whether a vehicle is in a straight drive state; a drive state determination means for determining whether the vehicle is in a drive state or a non-drive one; a steering input detection means for detecting the steering input of a driver; a drive state storage means S105 for storing a result detected by the steering input detection means when it is determined that the vehicle is in the drive state and that the drive is in a drive state; a non-drive state storage means S109 for storing a result detected by the steering input detection means if it is determined that the vehicle is in the non-drive state when it is determined that the vehicle is in the straight drive state; and an abnormality determination means S106 for determining abnormality, based on the drive state storage means and the non-drive state storage means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle drive control device for controlling a vehicle that independently drives left and right wheels.

  Conventionally, the present invention relates to a vehicle drive control device for controlling a vehicle that independently drives left and right wheels, and corrects the performance difference between the left and right power sources so as to eliminate the performance difference or determines the performance degradation of the power source. 2. Description of the Related Art There is known a vehicle drive control device equipped with a function for performing such functions.

  As a vehicle drive control device like the former, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 2005-160262), even when a drive characteristic difference caused by a change over time or the like occurs in a power source that drives a vehicle. A vehicle drive control device that controls the drive force of each wheel so that an unnecessary drive force difference does not occur between the left and right wheels is disclosed.

In addition, as a vehicle drive control device such as the latter, Patent Document 2 (Japanese Patent Laid-Open No. 2005-168184) discloses a vehicle drive control device that drives left and right wheels, respectively. In addition, a vehicle drive control device that detects a difference in rotation between left and right wheels, steering torque, and the like is disclosed.
JP 2005-160262 A JP 2005-168184 A

  By the way, in a vehicle that drives the left and right wheels, such as the vehicle drive control device described in Patent Document 1, it is necessary to measure the actual output torque when controlling so as not to cause a driving force difference due to secular change or the like. Yes, when measuring directly with a torque sensor, etc., sensors are required for the number of motors, which increases costs. To avoid the need to directly detect the output torque of each motor, the wheel alignment shifts due to an accident when the left and right rotation difference and steering torque during driving are simply viewed as in the vehicle drive control device described in Patent Document 2. If it is not possible to distinguish between the abnormal state and the torque abnormality of the power source and the wheel alignment deviation is corrected by the torque difference, the fuel consumption is deteriorated and the tire is unevenly worn.

  The wheel misalignment will be described with reference to FIGS. 11 and 12. 11 and 12 are diagrams for explaining a method for correcting torque abnormality in an electric vehicle of the front wheel steering / rear wheel independent drive system. 11 and 12 show the relationship between the body and wheels of the electric vehicle as viewed from above. In FIGS. 11 and 12, 2 is the body of the electric vehicle, 3 is the steering, and 4fl is the left front wheel. 4fr is a right front wheel, 4rl is a left rear wheel, and 4rr is a right rear wheel. In this electric vehicle, the left rear wheel 4rl and the right rear wheel 4rr are driven, and the left front wheel 4fl and the right front wheel 4fr are steered. 11 and 12, black arrows shown on the left rear wheel 4rl and the right rear wheel 4rr schematically indicate the magnitude of the torque of each wheel, and the white arrow in front of the vehicle indicates the vehicle. This indicates the moving direction. The torque of each wheel is generated by a motor (not shown) provided for each wheel.

  FIG. 11 (A) shows that, based on the operation of the driver of the electric vehicle, the torque command is given to both the left rear wheel 4rl and the right rear wheel 4rr in the same manner, as shown in the figure. The torque Tl of the rear wheel 4rl and the torque Tr of the right rear wheel 4rr are different, and the vehicle body 2 is shown moving toward the left. This is because even if the same torque command is issued to the same motor in an electric vehicle having motors on the left and right, the left and right outputs will differ due to aging. On the other hand, as shown in FIG. 11B, the driver is performing the steering operation so as to cancel the torque difference. Based on such steering operation, motor torque correction is performed so that the torque Tl of the left rear wheel 4rl and the torque Tr of the right rear wheel 4rr are the same (see FIG. 11C). Such torque correction includes a technique for detecting a steering torque or a steering operation angle during straight traveling and correcting a torque control value.

  Next, a description will be given of a case where wheel alignment deviation occurs in the electric vehicle due to an accident or the like. FIG. 12A shows a state in which the rear wheel of the electric vehicle causes a wheel alignment shift. In such a case, even if a torque command is issued to both the left rear wheel 4rl and the right rear wheel 4rr in the same manner, and there is no difference in performance between the left and right motors, as shown in the drawing, the wheel alignment deviation is not shown. For this reason, the electric self-propelled vehicle moves in the A direction. On the other hand, as shown in FIG. 12B, when the driver performs a steering operation to correct the trajectory as shown in FIG. 12B and performs the above-described torque correction based on this steering operation information, as shown in FIG. It becomes a state. In other words, with the conventional torque correction technology, it is not possible to distinguish between wheel misalignment caused by an accident or the like and the motor performance difference between the left and right motors. As a result, the driver cannot detect the abnormality, resulting in deterioration of the energy efficiency of the electric vehicle and uneven wear of the wheels.

  In order to solve the above-described problems, the invention according to claim 1 is directed to a vehicle drive control device that controls a vehicle capable of independently driving left and right wheels, and whether or not the vehicle is in a straight traveling state. A straight traveling state determining unit for determining, a driving state determining unit for determining whether the vehicle is in a driving state or a non-driving state, a steering input detecting unit for detecting a steering input of a driver, and the straight traveling state determining unit A drive state storage means for storing a detection result by the steering input detection means when the drive state determination means determines that the vehicle is in a drive state when it is determined that the vehicle is in a straight travel state; When the state determination means determines that the vehicle is in a straight traveling state, the steering input detection means detects when the drive state determination means determines that the vehicle is in a non-driving state. Characterized in that it comprises a non-drive state storage means for storing, and abnormality determination means for performing abnormality determination based on the said drive state storage unit and the non-drive state storage means.

  According to a second aspect of the present invention, in the vehicle drive control device according to the first aspect of the present invention, the abnormality determination means indicates that the detection result by the steering input detection means stored in the drive state storage means The result is that the input amount is shifted leftward or rightward, and the detection result by the steering input detection means stored in the non-driving state storage means is the result that the steering input amount is substantially in the center. Sometimes, it is determined that there is a torque difference between the left and right wheels.

  The invention according to claim 3 is the vehicle drive control device according to claim 1 or 2, wherein the abnormality determination means is detected by the steering input detection means stored in the drive state storage means. If the result and the detection result by the steering input detection means stored in the non-driving state storage means are both the result that the steering input amount is shifted to the left or right, It is characterized by determining.

  According to a fourth aspect of the present invention, in the vehicle drive control device according to any one of the first to third aspects, when a torque difference between the left and right wheels is detected by the abnormality determining means, a torque command is issued. Torque command correcting means for correcting is provided.

  According to a fifth aspect of the present invention, in the vehicle drive control device according to any one of the first to fourth aspects, a warning generating means for issuing a warning when a wheel alignment shift is detected by the abnormality determining means. It is characterized by providing.

  According to the vehicle drive control device according to claim 1, in the vehicle drive control device that controls a vehicle capable of independently driving left and right wheels, the vehicle travels straight and determines whether or not the vehicle is in a straight travel state. The state determination means, the drive state determination means for determining whether the vehicle is in the drive state or the non-drive state, the steering input detection means for detecting the steering input of the driver, and the straight travel state determination means cause the vehicle to be in the straight travel state. A drive state storage means for storing a detection result by the steering input detection means when the drive state determination means determines that the vehicle is in a drive state, and a straight traveling state determination means. When it is determined that the vehicle is in a straight traveling state, the detection result by the steering input detecting unit when the driving state determining unit determines that the vehicle is in a non-driving state is stored. By providing drive state storage means, and abnormality determination means for performing abnormality determination based on the drive state storage means and the non-drive state storage means, the torque difference between the power sources of the left and right wheels, wheel alignment deviation, etc. There is an effect that abnormality can be determined.

  According to the vehicle drive control device of the second aspect, in addition to the effect produced by the vehicle drive control device according to the first aspect, the abnormality determination means is the steering stored in the drive state storage means. The detection result by the input detection means is a result that the steering input amount is shifted leftward or rightward, and the detection result by the steering input detection means stored in the non-driving state storage means is the steering input amount. If the result is that it is substantially in the middle, there is an effect that the torque difference between the power sources of the left and right wheels can be accurately determined by determining that there is a torque difference between the left and right wheels.

  According to the vehicle drive control device of the third aspect, in addition to the effect produced by the vehicle drive control device according to the first or second aspect, the abnormality determination unit is stored in the drive state storage unit. Both the detection result by the steering input detection means and the detection result by the steering input detection means stored in the non-driving state storage means are the results that the steering input amount is shifted leftward or rightward. Sometimes, it is possible to accurately determine the wheel alignment deviation by determining that there is a wheel alignment deviation.

  According to the vehicle drive control device of the fourth aspect, in addition to the effect exerted by the vehicle drive control device according to any one of the first to third aspects, a torque difference between the left and right wheels by the abnormality determination means. When the is detected, by providing a torque command correcting means for correcting the torque command, there is an effect that the vehicle can be returned to a normal state.

  According to the vehicle drive control device of the fifth aspect, in addition to the effect exhibited by the vehicle drive control device according to any one of the first to fourth aspects, a wheel alignment deviation is detected by the abnormality determination means. By providing a warning generating means for issuing a warning, there is an effect that the vehicle abnormality can be transmitted to the driver.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a main configuration of an electric vehicle to which a vehicle drive control device according to an embodiment of the present invention is applied, and FIG. 2 is a vehicle drive control device according to an embodiment of the present invention. It is a figure which shows the system configuration | structure of the electric vehicle to which this is applied. In addition, about the system configuration | structure of FIG. 2, only the part relevant to the electric vehicle to which the drive control apparatus for vehicles of this embodiment is applied is extracted and shown. FIG. 1 is a top view of the relationship between the vehicle body and the wheels of the electric vehicle.

  1 and 2, 1 is an electric vehicle, 2 is a vehicle of the electric vehicle 1, 3 is a steering wheel, 4fl is a left front wheel, 4fr is a right front wheel, 4rl is a left rear wheel, 4rr is a right rear wheel, and 5fl is a left front wheel. Motor, 5fr for right front wheel motor, 5rl for left rear wheel motor, 5rr for right rear wheel motor, 6fl for left front wheel toe angle / camber angle adjustment mechanism, 6fr for right front wheel toe angle / camber angle adjustment 6rr is a left rear wheel toe angle / camber angle adjusting mechanism, 6rr is a right rear wheel toe angle / camber angle adjusting mechanism, 10 is an ECU (electronic control unit) comprising a CPU and an arithmetic unit, and 11 is not shown. An accelerator pedal sensor that detects the amount of depression of the accelerator pedal, 12 is a brake pedal sensor that detects the amount of depression of a brake pedal (not shown), 13 is a steering angle sensor of the steering 3, 14 A yaw rate sensor composed of a gyro, etc. 15 is a wheel speed sensor of each wheel 4fl, 4fr, 4rl, 4rr, 16 is a steering torque sensor for detecting the steering torque of the steering 3, 17 is a warning buzzer, 18 is Each warning display is shown.

  Hereinafter, the electric vehicle 1 will be described on the assumption that the left rear wheel 4rl and the right rear wheel 4rr are driven and steered by the left front wheel 4fl and the right front wheel 4fr. However, the embodiment of the present invention is not limited to this. Various embodiments are included unless departing from the spirit of the invention.

  Further, in the present embodiment, the description will be made on the assumption that the electric vehicle 1 is not provided with an engine and a generator for charging a battery and uses only electricity as a power energy source, but the electric vehicle 1 of the present invention is driven by the engine. The present invention may be applied to a vehicle in which electric power generated by an electric motor is charged in a battery.

  The amount of depression of the accelerator pedal by the driver is detected by the accelerator pedal sensor 11, and the amount of depression of the brake pedal by the driver is detected by the brake pedal sensor 12. The detected information is input to the ECU (electronic control unit) 10, and the motor control signal is output based on the program of the ECU (electronic control unit) 10 according to the driving mode set in the electric vehicle 1. Calculated. A control signal is output from the ECU (electronic control unit) 10 to the motors 5fl, 5fr, 5rl, and 5rr. In this embodiment, the motor drive is limited to the left rear wheel motor 5rl and the right rear wheel motor 5rr. Each motor 5fl, 5fr, 5rl, and 5rr is preferably a wheel motor, but the present invention is not limited to this. Moreover, the vehicle driven by a normal engine like the thing of Unexamined-Japanese-Patent No. 2004-330973 may be sufficient.

  The ECU (electronic control unit) 10 includes sensors for performing control other than the control described in the present invention, and control devices for controlling various devices mounted on the vehicle based on the sensing results of these sensors. A capacity storage device, a communication device, etc. are connected. The ECU (electronic control unit) 10 is connected to non-volatile storage means (not shown) and rewritable storage means. The nonvolatile storage means operates the electric self-propelled vehicle according to the present embodiment. And a program for other control as described above are stored and stored.

  The driver's operation of the steering wheel 3 is read by the steering angle sensor 13 and input to the ECU (electronic control unit) 10. Each wheel toe angle is based on a control signal output from the ECU (electronic control unit) 10. The camber angle adjusting mechanism 6fl, 6fr, 6rl, 6rr is controlled. In this embodiment, the adjustment of the toe angle / camber angle adjustment is limited to the left front wheel toe angle / camber angle adjusting mechanism 6fl and the right front wheel toe angle / camber angle adjusting mechanism 6fr.

  A steering angle may be mechanically changed using a normal link mechanism or the like.

  The yaw rate sensor 14 includes a gyro and the like, and detects the angular velocity of the vehicle 2. The information detected here is input to an ECU (electronic control unit) 10 and used for controlling the electric vehicle 1 in the present embodiment as will be described later. The wheel speed sensor 15 is provided on each wheel 4fl, 4fr, 4rl, 4rr. In the present embodiment, the wheel speed sensor 15 is used by an ECU (electronic control unit) 10 to determine whether the vehicle 2 is in a traveling state or in a stopped state. The steering torque sensor 16 is a sensor that detects the steering torque of the steering 3. In the present embodiment, the ECU (electronic control unit) 10 is mainly based on the distribution of the steering torque detected by the steering torque sensor 16. Control is performed as described later.

  Next, the detection principle of the torque difference / wheel alignment deviation of the left and right motors of the electric vehicle 1 according to the present embodiment will be described. 3 and 4 are diagrams schematically showing the principle of detection of torque difference and wheel alignment deviation of an electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. 3 and 4, the black arrows shown on the left rear wheel 4rl and the right rear wheel 4rr schematically indicate the magnitude of the torque of each wheel, and the white arrow in front of the vehicle indicates the vehicle. This indicates the moving direction. The torque of each wheel is generated by a motor provided for each wheel (not shown in FIGS. 3 and 4). Note that the present embodiment detects the torque difference between the left and right motors and the wheel alignment deviation of the wheels using the straight traveling state of the vehicle 2.

  FIG. 3 shows the principle for detecting the torque difference between the motors 5rl and 5rr. FIG. 3 (A) shows a state where the vehicle is being driven when the accelerator pedal is depressed by the driver, and FIG. 3 (B) is when the accelerator is not depressed by the driver. A state in which the vehicle 2 is traveling due to inertia is shown.

  FIG. 4 shows the principle for detecting wheel misalignment of the wheels 4rl and 4rr. FIG. 4 (A) shows a state where the vehicle is being driven when the accelerator pedal is depressed by the driver, and FIG. 4 (B) is when the accelerator pedal is not depressed by the driver. A state in which the vehicle 2 is traveling due to inertia is shown.

  As shown in FIG. 3 and FIG. 4, during driving traveling when the accelerator is on, torque as shown in the drawings is generated in each of the wheels 4rl and 4rr. On the other hand, in non-driving running when the accelerator is off, no torque is generated on the wheels 4rl and 4rr. In the case of FIG. 3A when there is a torque difference between the motors 5rl and 5rr and FIG. 4A when there is a wheel misalignment of the wheels 4rl and 4rr, in order to make the vehicle travel straight, the driver must Must be operated as shown. On the other hand, in non-driving running when the accelerator is off, when there is a torque difference in FIG. 3 (A), the driver does not need to perform a steering operation, and there is a wheel alignment deviation in FIG. 4 (A). The driver needs steering operation. In the present embodiment, the difference in torque between the left and right motors and the wheel misalignment of the wheel are detected from the difference in steering operation information by the driver when the accelerator is on and when the accelerator is off, that is, when driving and non-driving. To do.

  Next, an operation for detecting a torque difference between the left and right motors of the electric vehicle 1 to which the vehicle drive control device according to the embodiment of the present invention and a wheel alignment deviation of the wheel are detected, and an abnormality process will be described. FIG. 5 is a diagram showing a flowchart for control (for detection operation) of an electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. The control flow of FIG. 5 is based on the program of the electric vehicle 1 of the present embodiment described in the non-volatile storage means (not shown), the ECU (electronic control unit) 10 in FIG. 2, the accelerator pedal sensor 11, the brake pedal sensor. 12, steering angle sensor 13, yaw rate sensor 14, each wheel speed sensor 15, steering torque sensor 16, motor 5fl, 5fr, 5rl, 5rr, wheel toe angle / camber angle adjusting mechanism 6fl, 6fr, 6rl, 6rr, warning buzzer 17 and warning display 18 are realized by cooperation. It can be considered that the program is one routine of all control programs of the electric vehicle 1. The control according to the flowchart shown in FIG. 5 is started when an ECU (electronic control unit) 10 is started, and repeatedly executed at predetermined time intervals until an ignition switch (not shown) is turned off. Is done. Hereinafter, the yaw rate detected by the yaw rate sensor 14 is γ, the steering angle detected by the steering angle sensor 13 is θ, the steering torque of the steering 3 detected by the steering torque sensor 16 is TS, the accelerator pedal sensor 11, and the brake pedal sensor 12, a torque command (control signal) output from the ECU (electronic control unit) 10 to each of the left rear wheel motor 6 rl and the right rear wheel motor 6 rr based on Tl, Tr, and the wheel speed sensor 15 is detected by the vehicle 2. Let V be the vehicle speed. Here, the value of the steering torque TS in the right direction from the neutral position of the steering 3 is defined as a positive value, and the value of the steering torque TS in the left direction is defined as a negative value. Similarly, regarding the steering angle θ, the value of the steering angle θ in the right direction from the neutral position of the steering 3 is defined as a positive value, and the value of the steering angle θ in the left direction is defined as a negative value.

  In FIG. 5, when the process is started in step S100, the process first proceeds to step S101, and the ECU (electronic control unit) 10 reads signals from each sensor. Next, it progresses to step S102 and it is determined whether the vehicle 2 is a straight traveling state. That is, it is determined whether the yaw rate γ is smaller than γo (where γo is a value sufficiently close to 0). If the determination result in step S102 is Yes, it means that the vehicle is traveling straight, and the process proceeds to step S103. If the determination result in step S102 is No, data related to the present embodiment is not acquired, and the process proceeds to step S106.

  Next, in step S103, it is determined whether the torque command Tl to the left rear wheel motor 6rl is equal to the torque command Tr to the right rear wheel motor 6rr. That is, in step S103, it is determined whether or not Tl = Tr. If yes, the process proceeds to step S104. If the determination result in step S103 is No, data related to the present embodiment is not acquired, and the process proceeds to step S106.

  This process is not necessarily required unless the ECU (electronic control unit) 10 gives different commands to the left and right.

  In step S104, it is determined whether the left rear wheel motor 6rl and the right rear wheel motor 6rr are being driven. In step S104, it is determined whether or not the command torque Tl (= Tr, because of the determination result in step S103) is greater than a predetermined command torque value T1. In the case of determination Yes in step S104, the process proceeds to S105. If the determination in step S104 is No, the process proceeds to step S108.

  In step S105, the processing routine for acquiring data at the time of driving traveling described in the column of the detection principle of the present embodiment is executed. In the processing routine skipped from step S105, data relating to the steering torque TS is written in a driving RAM which is a rewritable storage means (not shown). This will be described later.

  In step S108, which proceeds when the determination in step S104 is No, it is determined whether the left rear wheel motor 6rl and the right rear wheel motor 6rr can be regarded as not being driven. Therefore, in step S108, it is determined whether or not | Tl | <To (or | Tr | <To, because of the determination result in step S103). However, the predetermined command torque value T1 and the predetermined torque value To satisfy the relationship of T1 >> To, and To is a value sufficiently close to 0. If the determination result of step S108 is Yes, the process proceeds to step S109. If the determination result in step S108 is No, data related to the present embodiment is not acquired, and the process proceeds to step S106.

  In step S109, the processing routine for acquiring data at the time of non-driving traveling described in the detection principle section of the present embodiment is executed. In the processing routine skipped from step S109, the data related to the steering torque TS is written into a non-drive time RAM which is a rewritable storage means (not shown). This will be described later.

  In step S106, based on the acquired data, a processing routine for determining whether there is an abnormality such as a torque difference of the motor of the electric vehicle 1 or a wheel alignment deviation of the wheel is executed. Details of this will be described later. In step S107, based on the determination result in step S106, a processing routine for responding to the abnormality is executed. Details of this will also be described later. Finally, the process proceeds to step S110, where the control flow for detecting the torque difference between the left and right motors and the wheel alignment misalignment of the wheels and the processing at the time of abnormality is END.

  Next, the processing routine of step S105 will be described. This routine is a routine for acquiring data during driving. FIG. 6 is a flowchart related to the writing process of the driving RAM of the electric vehicle to which the vehicle drive control apparatus according to the embodiment of the present invention is applied. This processing routine is a routine for performing data processing relating to the steering torque TS during driving as described above.

  In the following description, N is the total number of acquired data, and Don (0), Don (1),... Don (M) indicates a data array. When the maximum value of the steering torque data TS that can acquire TSmax and the minimum value of the steering torque data TS that can acquire -TSmax (where TSmax is a positive value), Don (n) is the steering torque TS. Can be defined as the number of data that fall within the range of −TSmax + 2TSmax × {n / (M + 1)} to −TSmax + 2TSmax × {(n + 1) / (M + 1)}.

  Hereinafter, a flowchart related to the writing process of the driving RAM will be described. When the process is started in step S200, the process proceeds to step S201, and the number of acquired data is counted. Here, when an ignition switch (not shown) of the electric vehicle 1 is turned on and a program of the ECU (electronic control unit) 10 is started, N = 0 is initialized. Then, every time step S201 in the flowchart is passed, N is incremented by 1 and the number of acquired data is counted.

  Next, in step S202, it is determined whether N, which is the total number of acquired data, is larger or smaller than a predetermined value Nmax. The predetermined value Nmax is an upper limit value of the number of acquired data. The reason for limiting the number of acquired data in this way is that it is not meaningful to increase the number of data unnecessarily. Therefore, in step S200, the predetermined value Nmax is compared with the number N of acquired data. If the determination result is No in step S202, the process proceeds to step S205, and the number of acquired data is adjusted. If the determination result of step S202 is Yes, it will progress to step S203 and acquisition of new data will be performed.

  In step S205, since the number of acquired data has exceeded the upper limit value Nmax, the number of acquired data is adjusted. Specifically, Don (0), Don (1),... Don (M) divided by 2, respectively, is set to Don (0), Don (1),. Reset it. However, at this time, the decimal part is rounded down. Next, in step S206, N is recalculated. That is, the sum of the newly reset Don (0), Don (1)... Don (M) is calculated.

  In step S203, calculation for reading new data is performed. That is, the newly acquired steering torque data TS is which data of Don (0), Don (1) ·· Don (n) ·· Don (M) (that is, n is how many). Is calculated. Specifically, n can be calculated by n = int (TS / (TSmax / (M / 2)) + M / 2 + 0.5). In step S204, Don (n) is incremented by +1 based on n obtained in step S203. Proceeding to step 207, this processing routine is terminated.

  Next, the processing routine of step S109 will be described. This routine is a routine for acquiring data during non-driving travel. FIG. 7 is a diagram showing a flowchart relating to the writing process of the non-driving RAM of the electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. As described above, this processing routine is a routine for performing data processing related to the steering torque TS during non-driving travel.

  In the following description, K is the total number of acquired data, and Doff (0), Doff (1)... Doff (M) indicates a data array. When the maximum value of the steering torque data TS that can acquire TSmax and the minimum value of the steering torque data TS that can acquire -TSmax (where TSmax is a positive value), Don (n) is the steering torque TS. Can be defined as the number of data that fall within the range of −TSmax + 2TSmax × {n / (M + 1)} to −TSmax + 2TSmax × {(n + 1) / (M + 1)}.

  A flowchart relating to the writing process of the non-drive RAM will be described below. When the process is started in step S300, the process proceeds to step S301, and the number of acquired data is counted. Here, when an ignition switch (not shown) of the electric vehicle 1 is turned on and a program of the ECU (electronic control unit) 10 is started, K = 0 is initialized. Then, every time step S301 in the flowchart is passed, K is incremented by 1 and the number of acquired data is counted.

  Next, when proceeding to step 302, it is determined whether K, which is the total number of acquired data, is larger or smaller than a predetermined value Kmax. The predetermined value Kmax is an upper limit value of the number of acquired data. The reason for limiting the number of acquired data in this way is that it is not meaningful to increase the number of data unnecessarily. In step S300, therefore, the predetermined value Kmax is compared with the number K of acquired data. If the determination result is No in step S302, the process proceeds to step S305, and the number of acquired data is adjusted. If the determination result of step S302 is Yes, it will progress to step S303 and acquisition of new data will be performed.

  In step S305, since the acquired data number exceeds the upper limit value Nmax, the acquired data number is adjusted. Specifically, Doff (0), Doff (1),... Doff (M) divided by 2, respectively, Doff (0), Doff (1),. Reset it. However, at this time, the decimal part is rounded down. Next, in step S306, K is recalculated. That is, the sum of Doff (0), Doff (1),... Doff (M) newly set is calculated.

  In step S303, calculation for reading new data is performed. That is, the newly acquired steering torque data TS is Doff (0), Doff (1) ·· Doff (n) ·· Doff (M) (ie, how many are n). Is calculated. Specifically, n can be calculated by n = int (TS / (TSmax / (M / 2)) + M / 2 + 0.5). In step S304, Doff (n) is incremented by +1 based on n obtained in step S303. Proceeding to step 307, this processing routine is terminated.

  According to the processing routine of step S105 and the processing routine of step S109 as described above, a histogram as shown in FIG. 8 can be obtained. FIG. 8 is a diagram showing a concept of data processing in an electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. Here, the histograms shown in FIGS. 8A and 8B are created based on the data acquired by the writing process of the driving RAM, but are acquired by the writing process of the non-driving RAM. Since it can be considered in the same way for the obtained data, the description will be made based on a histogram based on data obtained by the writing process of the driving RAM. The processing routine of step S105 creates a value obtained by dividing the value from −TSmax, which is the minimum value that can be taken by the steering torque data TS, to the maximum value TSmax by a width of (M + 1), and enters this divided width. It is a histogram of the number of steering torque data TS. When there is no abnormality such as a difference in torque between the left and right motors and a wheel misalignment of the wheels, the steering torque should be a value close to 0, so that a histogram as shown in FIG. Conversely, when there is an abnormality such as a difference in torque between the left and right motors or a wheel misalignment of the wheels, the steering torque becomes a value deviated from 0, so that a histogram as shown in FIG. Become.

  Next, the processing routine of step S106 will be described. This routine executes a processing routine for determining whether there is an abnormality such as a torque difference of the motor of the electric vehicle 1 or a wheel alignment deviation of the wheel based on the acquired steering torque data. FIG. 9 is a diagram illustrating a flowchart relating to abnormality determination processing for an electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. Hereinafter, a flowchart relating to the abnormality determination process will be described.

  When the process is started in step S400, the process proceeds to step S401, where it is determined whether the number of steering torque data acquired so far is sufficient for determination. That is, it is determined whether N is larger than No which is a predetermined threshold and whether K is larger than Ko which is a predetermined threshold. Note that No is a value that satisfies No <Nmax / 2, and Ko is a value that satisfies Ko <Kmax / 2. This is because the number of acquired data is adjusted during the writing process flow of the driving RAM of FIG. 6 and the writing process flow of the non-driving RAM of FIG.

  If the result of the determination is No in step S401, a sufficient number of data for performing the abnormality determination has not been obtained, and the process proceeds to step S405 and returns. If the result of determination in step S401 is Yes, a sufficient number of data for performing abnormality determination has been obtained, and therefore processing for abnormality determination is performed in the flow after step S402.

In step S402, a value Avg (Don) is calculated. Avg (Don) is
Avg (Don) = (Don (0) × 0 + Don (1) × 1 +. + Don (M) × M) / N
And is a value such as a weighted average of each data in the histogram. This Avg (Don) can be roughly considered as an average value of the steering torque at the timing of the accelerator on in the straight traveling state. This is also referred to as a driving average steering input amount.

In step S403, a value Avg (Doff) is calculated. Avg (Doff) is
Avg (Doff) = (Doff (0) × 0 + Doff (1) × 1 +. + D0ff (M) × M) / K
Is defined by This Avg (Doff) can be roughly considered as an average value of the steering torque at the accelerator-off timing in the straight traveling state. This is also referred to as a non-driving average steering input amount.

In step S404, an abnormality is determined based on the calculated Avg (Don) and Avg (Doff) (classifying what kind of abnormality has occurred). Α is a predetermined value and is a value related to an allowable amount in the abnormality determination. From the neutral position of the steering 3, the value of the steering torque TS in the right direction is defined as a positive value, and the value of the steering torque TS in the left direction is defined as a negative value. Judgment.
(Case 1)
Avg (Doff) <M / 2-α
And Avg (Don) <M / 2-α
In this case, the average steering torque during straight driving / non-driving and the average steering torque during straight driving / driving are both shifted to the left (the average steering input during driving and the average steering input during non-driving). Therefore, it is determined that the wheel alignment is directed rightward.
(Case 2)
M / 2−α ≦ Avg (Doff) <M / 2 + α
And Avg (Don) <M / 2-α
Is, the average steering torque during straight driving and driving is shifted leftward (the average steering input amount during driving is shifted leftward, and the average steering input amount during non-driving is substantially in the center). Torque of left rear wheel motor 5rl)> (torque of right rear wheel motor 5rr)
It is determined that
(Case 3)
M / 2−α ≦ Avg (Doff) <M / 2 + α
And M / 2 + α ≦ Avg (Don)
When, the average steering torque during straight driving and driving is shifted in the right direction ((the average steering input amount during driving is shifted rightward and the average steering input amount during non-driving is substantially in the center)) , (Torque of right rear wheel motor 5rr)> (torque of left rear wheel motor 5rl).
(Case 4)
M / 2 + α ≦ Avg (Doff)
And M / 2 + α ≦ Avg (Don)
In this case, the average steering torque during straight driving / non-driving and the average steering torque during straight driving / driving are both shifted to the right (the average steering input during driving and the average steering input during non-driving). Therefore, it is determined that the wheel alignment is directed leftward.
(Case 5)
M / 2−α ≦ Avg (Doff) ≦ M / 2 + α
And M / 2−α ≦ Avg (Don) ≦ M / 2 + α
In this case, the average steering torque during straight driving / non-driving and the average steering torque during straight driving / driving are not shifted (both the average steering input during driving and the average steering input during non-driving are both approximately It is determined that there is no abnormality.
(Case 6)
When none of (Case 1) to (Case 5) applies, it is determined that the abnormality is neither a simple torque difference between the left and right motors nor a wheel alignment misalignment of the wheels.

  Next, the processing routine of step S107 will be described. This routine is a processing routine for responding to these abnormalities based on the type of abnormality determined in S106. FIG. 10 is a diagram showing a flowchart relating to the abnormality processing of the electric vehicle to which the vehicle drive control device according to the embodiment of the present invention is applied. Hereinafter, a flow chart relating to the abnormal time process will be described.

  When the process is started in step S500, the process proceeds to step S501, and it is determined whether there is an abnormality in the abnormality determination processing routine. If it is determined No in step S501, the process proceeds to step S504 and returns.

If it is determined as Yes in step S501, the process proceeds to step S502, and abnormality processing is performed based on the type of abnormality determined in S106. For abnormal processing,
(A) (torque of left rear wheel motor 5rl)> (torque of right rear wheel motor 5rr):
Correction is made to decrease the torque of the left rear wheel motor 5rl, or correction is made to increase the torque of the right rear wheel motor 5rr.
When using the former correction, if the correction command torque of the left rear wheel motor 5rl is Tlc and the torque correction value is Tlo,
Tlc (correction command torque) = Tl (command torque) −Tlo (torque correction value)
When the latter correction is used, if the correction command torque of the right rear wheel motor 5rr is Trc and the torque correction value is Tro,
Trc (correction command torque) = Tr (command torque) + Tro (torque correction value)
Correct as follows.
(B) When (torque of right rear wheel motor 5rr)> (torque of left rear wheel motor 5rl):
Correction is made to decrease the torque of the right rear wheel motor 5rr, or correction is made to increase the torque of the left rear wheel motor 5rr.
When using the former correction, if the correction command torque of the right rear wheel motor 5rr is Trc and the torque correction value is Tro,
Trc (correction command torque) = Tr (command torque) −Tro (torque correction value)
When the latter correction is used, if the correction command torque of the left rear wheel motor 5rl is Tlc and the torque correction value is Tlo,
Tlc (correction command torque) = Tl (command torque) + Tlo (torque correction value)
Correct as follows.

As a method for obtaining the torque correction value in the above (a) and (b), a method for obtaining a steering torque deviation amount by a calculation formula, a method for obtaining a steering torque deviation amount by a map, and the like in this field. A known method may be used as appropriate.
(C) When wheel alignment is abnormal:
A warning buzzer 17 and a warning display 18 provided in a driver's seat (not shown) of the electric vehicle 1 are used to notify the driver that an alignment abnormality has occurred. When the electric vehicle 1 is provided with a wheel alignment correction mechanism, automatic correction may be performed by this.
(D) Other abnormalities:
A warning buzzer 17 and a warning display 18 provided in a driver's seat (not shown) of the electric vehicle 1 are used to warn the driver that some abnormality has occurred.

  In step S503, when the torque correction is performed in the above (a) and (b), the driving RAM and the non-driving RAM are initialized. Then, the process proceeds to step S504 and returns.

  In the present embodiment, only the rear wheels are driven. However, only the front wheels may be driven or both the front and rear wheels may be driven. What is necessary is just to correct | amend so that the sum of the torque of each wheel may correspond.

  In addition, the determination during driving driving and non-driving driving is performed using the command torque, but it may be performed based on the accelerator pedal opening. In this case, driving driving when the accelerator pedal opening is equal to or greater than a predetermined value. In this case, it is determined that the vehicle is not driven and is approximately 0. Furthermore, other means may be used for determination of driving driving and non-driving driving as long as the driving state of the vehicle can be determined.

  In this embodiment, the steering torque TS during straight / non-driving travel and the steering torque TS data during straight / driving travel are acquired and used for abnormality determination. However, as another embodiment, May be configured such that the abnormality determination is performed by acquiring data of the steering angle θ of the steering wheel 3 during straight traveling / non-driving traveling and the steering angle θ of the steering wheel 3 during straight traveling / driving traveling. Since the steering torque TS is also the driver's steering input information that is an amount proportional to the steering rotation angle θ, the detection principle of the present invention can be used. In this case as well, data processing similar to that for the steering torque TS may be performed. In addition, various other methods may be adopted as appropriate for the data processing of the abnormality determination, and the point is that all are included in the scope of the present invention as long as the detection principle of the left / right motor torque difference / wheel alignment deviation described above is used. It is what

  As described above, according to the embodiment of the present invention, in addition to the torque difference between the power source for the left wheel and the power source for the right wheel, it is possible to detect the wheel misalignment. Therefore, it is possible to suppress the deterioration of the energy efficiency of the vehicle and the occurrence of uneven wear of the wheels. Furthermore, since a torque difference and wheel alignment deviation between the left and right power sources can be detected without providing a torque sensor for detecting the torque of the wheel power source, the cost merit is great.

It is a figure which shows the outline of the main structures of the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure which shows the system configuration | structure of the electric vehicle to which the vehicle drive control apparatus which concerns on embodiment of this invention is applied. It is a figure which shows typically the detection principle of the torque difference and wheel alignment shift | offset | difference of an electric vehicle to which the vehicle drive control apparatus which concerns on embodiment of this invention is applied. It is a figure which shows typically the detection principle of the torque difference and wheel alignment shift | offset | difference of an electric vehicle to which the vehicle drive control apparatus which concerns on embodiment of this invention is applied. It is a figure which shows the flowchart for control (for detection operation | movement) of the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure which shows the flowchart which concerns on the write-in process of RAM for driving at the time of the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure which shows the flowchart which concerns on the write-in process of RAM for non-drive of the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure which shows the concept of the data processing in the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure which shows the flowchart which concerns on the abnormality determination process of the electric vehicle to which the vehicle drive control apparatus which concerns on embodiment of this invention is applied. It is a figure which shows the flowchart which concerns on the process at the time of abnormality of the electric vehicle to which the drive control apparatus for vehicles which concerns on embodiment of this invention is applied. It is a figure explaining the correction method of the torque abnormality in the electric vehicle of a front wheel steering and a rear-wheel drive system. It is a figure explaining the correction method of the torque abnormality in the electric vehicle of a front wheel steering and a rear-wheel drive system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric vehicle, 2 ... Vehicle, 3 ... Steering, 4fl ... Left front wheel, 4fr ... Right front wheel, 4rl ... Left rear wheel, 4rr ... Right rear wheel, 5fl ... Left front wheel motor, 5fr ... Right front wheel motor, 5rl ... Left rear wheel motor, 5rr ... Right rear wheel motor, 6fl ... Left front wheel toe angle / camber angle adjustment Mechanism, 6fr ... Toe angle / camber angle adjustment mechanism for right front wheel motor, 6rl ... Toe angle / camber angle adjustment mechanism for left rear wheel motor, 6rr ... Toe angle for motor for right rear wheel Camber angle adjusting mechanism, 10 ... ECU (electronic control unit), 11 ... accelerator pedal sensor, 12 ... brake pedal sensor, 13 ... yaw rate sensor, 15 ... wheel speed sensor, 16 ...・ Steering torque sensor, 17 ・· Warning buzzer, 18 ... warning display

Claims (5)

In a vehicle drive control device for controlling a vehicle capable of independently driving left and right wheels,
Straight running state determining means for determining whether the vehicle is in a straight traveling state;
Driving state determination means for determining whether the vehicle is in a driving state or a non-driving state;
Steering input detection means for detecting the steering input of the driver;
Stores the detection result by the steering input detecting means when the straight running state determining means determines that the vehicle is in the straight running state and the driving state determining means determines that the vehicle is in the driving state. Driving state storage means;
When the straight traveling state determining means determines that the vehicle is in a straight traveling state, the detection result by the steering input detecting means when the driving state determining means determines that the vehicle is in a non-driving state is stored. Non-driving state storage means for
A vehicle drive control apparatus comprising: an abnormality determination unit that performs an abnormality determination based on the drive state storage unit and the non-drive state storage unit. The abnormality determining means is
The detection result by the steering input detection means stored in the drive state storage means is a result that the steering input amount is shifted leftward or rightward, and is stored in the non-drive state storage means 2. The vehicle drive control according to claim 1, wherein when the detection result by the steering input detection means is a result that the steering input amount is substantially in the center, it is determined that there is a torque difference between the left and right wheels. apparatus. The abnormality determining means is
Both the detection result by the steering input detection means stored in the driving state storage means and the detection result by the steering input detection means stored in the non-driving state storage means have the steering input amount leftward or rightward. 3. The vehicle drive control device according to claim 1, wherein the vehicle drive control device determines that there is a wheel alignment shift when the result is that the wheel alignment is shifted. 4. The vehicle drive control according to claim 1, further comprising: a torque command correcting unit that corrects a torque command when a torque difference between the left and right wheels is detected by the abnormality determining unit. 5. apparatus. The vehicle drive control device according to any one of claims 1 to 4, further comprising a warning generation unit that issues a warning when a wheel alignment shift is detected by the abnormality determination unit.

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