JP2020129924A - Vehicle control apparatus - Google Patents

Abstract

To provide a vehicle control apparatus capable of controlling the behavior during traveling of a vehicle when one drive part breaks down in an independent drive vehicle using either front wheels or rear wheels as drive wheels.SOLUTION: An in-wheel motor (IWM) command device 12 gives torque commands based on the target value of the longitudinal force sum of a vehicle and the target value of the target yaw moment thereof to one drive part and the other drive part. In addition, when an abnormality detector 16 detects an abnormality in any IWM of a right first drive motor 20R1, a right second drive motor 20R2, a left first drive motor 20L1, and a left second drive motor 20L2, the IWM command device 12 sets the drive force of the IWM where the abnormality is detected to 0. When a request torque to a normal IWM for driving the same drive wheel as the IWM where the abnormality is detected exceeds the rated torque of the normal IWM, the IWM command device 12 sets the torque commands so that the request torque to the normal IWM becomes equal to or less than the rated torque.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle control device that controls a motor that is a power source of a vehicle.

An in-wheel motor (hereinafter abbreviated as “IWM”) provided inside a hub of a wheel of an electric vehicle (EV) or the like rotates a pair of left and right front wheels, rear wheels, or front and rear wheels individually. Used for independently driven vehicles that drive.

Since the drive force is transmitted almost directly to the wheel, the IWM has no energy loss due to conventional gears and drive shafts, and by omitting them, the power source can be made compact and the vehicle manufacturing cost can be suppressed. it can.

In addition, since the driving force distribution can be freely changed by controlling each wheel individually, there are various advantages such as easy construction of the skid prevention device and the traction control system.

However, the IWM is required to have high durability because the IWM continues to receive an impact from the road surface via the tire while the vehicle is traveling. Further, since the mounting position of the motor is lowered, it is necessary to deal with water infiltration and foreign matter on the road, and since the motor is adjacent to the brake, it is necessary to take measures against heat during braking.

Even if the IWM is manufactured by paying attention to its durability and reliability, the IWM may fail due to the impact from the road surface, the water immersion, the heat at the time of braking, or the like. In Patent Document 1, in a vehicle having four wheels equipped with an IWM, vehicle control for performing control for maintaining vehicle speed and turning performance with the remaining three wheels IWM even if one wheel IWM fails while the vehicle is traveling. A device invention is disclosed.

JP, 2005-015687, A

However, since the vehicle control device described in Patent Document 1 is premised on that all wheels of a four-wheel vehicle are equipped with an IWM that is a drive unit, it is necessary to design the suspension of all wheels to be IWM compatible. In particular, since a steering mechanism is incorporated in the front wheels, there is a problem in that the design of a front wheel suspension compatible with IWM tends to be complicated, resulting in an increase in vehicle development cost. Further, there is a problem that the unsprung load of the vehicle is increased by providing the IWM on all four wheels, which affects the riding comfort.

The present invention has been made in consideration of the above facts, and in an independently driven vehicle that uses one of the front wheels or the rear wheels as a driving wheel, controls the behavior of the vehicle during traveling when one drive unit fails. An object of the present invention is to provide a vehicle control device capable of performing the above-mentioned operation.

In order to achieve the above-mentioned object, the invention according to claim 1 is provided with two on each of the left and right sides of the drive wheels for driving the drive wheels of a left-right independent drive vehicle that drives either the front wheels or the rear wheels. Drive unit, a vehicle target setting unit that sets a target longitudinal force sum and a target yaw moment of the vehicle, an abnormality detection unit that detects an abnormality of the drive unit, and the target longitudinal force sum and the target yaw moment When a torque command is issued to the drive unit, and when the abnormality detection unit detects an abnormality in any of the drive units, the drive force of the abnormal drive unit in which the abnormality is detected is set to 0, When the required torque for the normal drive unit that drives the same drive wheels exceeds the rated torque of the normal drive unit, a drive command unit that sets the torque command so that the required torque is equal to or less than the rated torque. Prepare

According to the first aspect of the present invention, when one drive unit fails, another normal drive unit is used to drive the vehicle and a normal drive unit that drives the same drive wheels as the failed drive unit. When the required torque exceeds the rated torque of the normal drive unit, the torque command is set so that the required torque becomes equal to or less than the rated torque.

According to a second aspect of the present invention, in the first aspect of the present invention, the drive command unit issues a command of a required torque relating to transient control requiring responsiveness and a command of a required torque having a minute fluctuation to the vehicle. A command of a required torque relating to a constant torque with a small change amount is input to each of the drive units provided on the outer side in the width direction, and is input to the drive units provided on the inner side in the vehicle width direction.

According to the second aspect of the present invention, the command of the required torque relating to the control requiring the responsiveness is provided outside in the vehicle width direction in consideration of the delay component of the torque transmission by the transmission mechanism such as the drive shaft and the gear. The required torque command relating to a constant torque with a small change amount is input to the drive unit provided inside the vehicle width direction.

As described above, according to the present invention, when one drive unit fails, one of the front wheels or the rear wheels is set by setting the required torque for the normal drive unit to be equal to or less than the rated torque of the normal drive unit. In an independently driven vehicle having drive wheels, it is possible to control the behavior of the vehicle during traveling when one drive unit fails.

It is a block diagram which shows the outline of the vehicle control apparatus which concerns on embodiment of this invention. FIG. 7 is a block diagram showing a case where an abnormality occurs in the right second drive motor and the right second drive motor cannot be expected as a power source. 3 is a flowchart showing an example of torque control during abnormality of the vehicle control device according to the embodiment of the present invention.

Embodiments for carrying out the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an outline of a vehicle control device 100 according to the present embodiment.

As shown in FIG. 1, vehicle control device 100 according to the present embodiment is a control device that controls a motor that drives rear wheels of vehicle 30. The vehicle 30 includes a right first drive motor 20R1 and a right second drive motor 20R2 on the right rear wheel 22R side, and a left first drive motor 20L1 and a left second drive motor 20L2 on the left rear wheel 22L side, for a total of four IWMs. And a left-right independent drive vehicle that individually drives a pair of left and right rear wheels.

The vehicle 30 detects the movement of the vehicle ahead by the radar, automatically moves the brake and the accelerator to control the speed, and makes the vehicle follow the preceding vehicle by ACC (Adaptive Cruise Control), the radar and the vehicle-mounted camera. When a vehicle or obstacle is detected and there is a possibility of a collision, the brakes are automatically applied to reduce damage and PCS (Pre-Crash Safety) and the in-vehicle camera recognize the road white line and run along the road shape. In addition, an automatic driving control unit 40 that performs advanced automatic driving control such as LKA (Lane Keeping Assist) that automatically moves the steering and controls the vehicle to run in the center of the lane is provided.

Further, the vehicle 30 has an operation unit 50 including a steering wheel, a brake, and an accelerator operated by an occupant.

Further, the vehicle 30 is configured to be capable of DYC (Direct Yaw-moment Control) control for controlling the direction of the vehicle 30 by the braking/driving force of each wheel.

The command related to the automatic driving from the automatic driving control unit 40 and the command according to the operation of the steering wheel, the brake, and the accelerator from the operation unit 50 are input to the vehicle target calculation unit 10.

The vehicle target calculation unit 10 is connected to a detection unit 14 that includes a vehicle speed sensor that detects the speed (vehicle speed) of the vehicle 30 and a yaw rate sensor that detects changes in the yaw rate of the vehicle 30. The vehicle target calculation unit 10 receives an input from the detection unit 14 according to one of a command related to automatic driving from the automatic driving control unit 40 and a command from the operation unit 50 according to steering, brake, and accelerator operations. Based on the current vehicle speed and yaw rate, the sum of the longitudinal force (driving force or braking force) of the entire vehicle 30 and the vehicle target value that is the target value of the yaw moment are determined.

The IWM command device 12 determines each of the right first drive motor 20R1, the right second drive motor 20R2, the left first drive motor 20L1 and the left second drive motor 20L2 based on the vehicle target value determined by the vehicle target calculation unit 10. Control the rotation of the IWM.

More specifically, the IWM command device 12 calculates the instruction torque of each IWM from the vehicle target value and controls the right first drive motor 20R1 and the right second drive motor 20R2 with the torque instruction related to the instruction torque. It outputs to a right motor control device (not shown) and a left motor control device (not shown) that controls the left first drive motor 20L1 and the left second drive motor 20L2, respectively.

The torque command is determined for each of the left and right wheels based on the sum of the front-rear force of the vehicle 30 and the torque difference between the left and right wheels in the DYC control. As described below, the IWM command device 12 determines torque commands to the IWMs of two on one side and a total of four IWMs as follows, and outputs them to each of the right motor control device and the left motor control device.

The torque command for each of the left and right wheels is based on the IWM on the outside in the vehicle width direction (the right second drive motor 20R2 for the right rear wheel and the left first drive motor 20L1 for the left rear wheel) and the IWM on the vehicle width direction inside (the right for the right rear wheel The first drive motor 20R1 and the left rear wheel are distributed to the left second drive motor 20L2).

Since the two IWMs on one side and the tire may be connected via a transmission mechanism such as a drive shaft or gear, the transmission mechanism serves as a source of a delay component when transmitting the motor torque to the tire. Become. In consideration of such a delay component, a request torque command relating to transient control requiring responsiveness or a request torque command having a minute fluctuation is provided to an IWM provided on the outer side in the vehicle width direction that is not easily affected by the transmission mechanism. A request torque command relating to a constant torque with a small change amount is input to the IWM provided on the inner side in the vehicle width direction.

Further, the vehicle control device 100 according to the present embodiment monitors the IWM state of each of the right first drive motor 20R1, the right second drive motor 20R2, the left first drive motor 20L1 and the left second drive motor 20L2. The abnormality detector 16 is provided. When the abnormality detector 16 detects an abnormality in any of the four IWMs, the abnormality detector 16 outputs a signal indicating which IWM is abnormal to the vehicle target calculation unit 10 and the IWM command device 12.

The IWM is generally a current sensor that detects a current of a drive circuit such as an inverter and a winding of a motor, a rotation angle sensor that detects a rotation angle of a rotor (rotor), and a temperature sensor that detects a temperature in a housing of the IWM. It is equipped with sensors such as. As an example, the abnormality detector 16 detects when the current value detected by the current sensor is equal to or larger than a predetermined current threshold value, when the change in the rotation angle detected by the rotation angle sensor is slower than the command value, and when the temperature sensor detects the change. If the measured temperature is equal to or higher than the predetermined temperature threshold value, it is determined that the IWM is abnormal in either case.

FIG. 2 is a block diagram showing a case where an abnormality has occurred in the right second drive motor 20R2 and the right second drive motor 20R2 cannot be expected as a power source. The abnormality detector 16 outputs a signal indicating that an abnormality has occurred in the right second drive motor 20R2 to the vehicle target calculation unit 10 and the IWM command device 12.

As shown in FIG. 2, for example, when the right second drive motor 20R2 fails, the vehicle control device 100 according to the present embodiment uses the right first drive motor 20R1, the left first drive motor 20L1, and the left second drive. The DYC control is continued by the motor 20L2.

Specifically, the current operation input from the detection unit 14 is performed in accordance with one of the instruction related to the automatic operation from the automatic operation control unit 40 and the instruction according to the operation of the steering, the brake, and the accelerator from the operation unit 50. The point that the vehicle target value, which is the target value of the longitudinal force sum and the yaw moment of the vehicle 30, is determined from the vehicle speed and the yaw rate is the same as in normal operation. However, when any of the IWMs (the right second drive motor 20R2 in FIG. 2) fails, the abnormality detector 16 identifies the right second drive motor 20R2 that is the abnormal IWM, and the right second drive motor 20R2 A signal indicating an abnormality is output to the vehicle target calculation unit 10 and the IWM command device 12.

The IWM command device 12 sets the torque command of the failed right second drive motor 20R2 to 0, and calculates the torque commands of the remaining three IWMs.

The vehicle target calculation unit 10 and the IWM command device 12 monitor whether or not the torque demand of the right rear wheel 22R exceeds the rated torque of the right first drive motor 20R1, and the torque demand of the right rear wheel 22R makes the right first drive. When the rated torque of the motor 20R1 is exceeded, the torque command value related to the vehicle target value is lowered so that the torque request of the right rear wheel 22R becomes equal to or less than the rated torque of the right first drive motor 20R1. The process of reducing the value of the torque command is performed by either the vehicle target calculation unit 10 or the IWM command device 12, but the process will be described below as being performed by the IWM command device 12.

FIG. 3 is a flowchart showing an example of torque control during an abnormality of vehicle control device 100 according to the present embodiment. FIG. 3 shows an example of processing when the right second drive motor 20R2 is abnormal.

In step 300, the vehicle target torque is calculated based on the sum of the front-rear force of the vehicle 30 and the torque difference between the left and right wheels in the DYC control. The vehicle target torque is a vehicle target torque T _total that is a torque command for all of the drive wheels of the vehicle 30 (in the present embodiment, the right rear wheel 22R and the left rear wheel 22L), and the target torque of the motor that constitutes the IWM. A vehicle target torque guard T _guard for preventing the rating from being exceeded. As shown in FIG. 3, the vehicle target torque guard T _guard has an initial value of 0.

In step 302, the difference between the vehicle target torque T _total and the vehicle target torque guard T _guard is calculated, and the difference is set as a new vehicle target torque T _total .

In step 304, the vehicle target torque T _total obtained in step 302 is divided based on the torque difference between the left and right wheels in the DYC control, and each of the right driving wheel torque Tr and the left driving wheel torque Tl is calculated.

In step 306, the motor command torque of each of the three IWMs except for the abnormal right second drive motor 20R2 is calculated. As described above, since the motor command torque of the failed right second drive motor 20R2 is 0, the motor command torque Tr(1) of the right first drive motor 20R1 is the same as the right drive wheel torque Tr.

Further, the motor command torque Tl(1) of the left first drive motor 20L1 and the motor command torque Tl(2) of the left second drive motor 20L2 are distributed from the left drive wheel torque Tl as described above. Of the left drive wheel torque Tl, a command for transient control that requires responsiveness or a request torque for a minute fluctuation is set as a motor command torque Tl(1) of the left first drive motor 20L1 to a constant torque with a small change amount. The command of the required torque is distributed as the motor command torque Tl(2) of the second left drive motor 20L2.

In step 308, the right drive wheel torque rating is determined. In step 308, it is determined whether or not the motor command torque Tr(1) of the right first drive motor 20R1 calculated in step 306 exceeds the rated torque Tr(1)max of the right first drive motor 20R1. In step 308, if the motor command torque Tr(1) is less than or equal to the rated torque Tr(1)max, the process is returned. If the motor command torque Tr(1) exceeds the rated torque Tr(1)max in step 308, the procedure proceeds to step 310.

In step 310, the value of the right drive wheel torque guard T _guard is calculated. The right drive wheel torque guard T _guard is a value that is twice the difference between the motor command torque Tr(1) and the rated torque Tr(1)max. After the value of the right drive wheel torque guard T _guard is calculated in step 310, the procedure shifts to step 302 and the steps 302 to 308 are performed.

As described above, the vehicle control device 100 according to the present embodiment allows the vehicle 30 having the IWM only on the rear wheels to continue traveling of the vehicle 30 by another IWM when one IWM fails. You can Since the vehicle 30 has two IWMs on one rear wheel and a total of four IWMs on the left and right rear wheels, even if one of the four IWMs fails, the other three IWMs drive the vehicle. The behavior of the vehicle 30 inside can be controlled.

As a result of the failure of one IWM, even when the drive wheels are driven by one normal IWM, in order to accurately control the behavior of the vehicle 30, the torque of the drive wheels in which the two IWMs are normally operating is Relatively, the torque of the drive wheels driven by IWM of 1 is determined. However, in such a case, the torque of the drive wheel driven by the 1 IWM may exceed the rated torque of the 1 IWM. The vehicle control device 100 according to the present embodiment calculates the target torque guard T _guard of the drive wheels and obtains the target torque guard T _guard by subtracting the target torque guard T _guard from the vehicle target torque T _total of all the drive wheels of the vehicle 30. By setting the torques of the left and right driving wheels based on the new vehicle target torque T _total , even if one IWM fails, the other IWM can be operated in a state below the rating.

The vehicle control device 100 according to the present embodiment is used for the vehicle 30 that is a left-right independent drive vehicle that individually drives a pair of left and right rear wheels, but is used for a left-right independent drive vehicle that individually drives a pair of left and right front wheels. May be. Further, although the vehicle control device 100 according to the present embodiment has the vehicle target calculation unit 10 and the IWM command device 12 as separate configurations, each may be configured as one device.

Further, the vehicle control device 100 according to the present embodiment, which distributes the torque command so that the vehicle can travel with a normal motor, is different from the vehicle 30 having the IWM in that there is no differential gear and the left and right wheels are independently motorized. It is also applicable to a vehicle with an on-board two-motor connected to.

The drive unit in the claims is the right first drive motor 20R1, the right second drive motor 20R2, the left first drive motor 20L1 and the left second drive motor 20L2, and the vehicle target setting unit is the vehicle target calculation unit 10. The abnormality detecting section corresponds to the abnormality detector 16, and the drive command section corresponds to the IWM command device 12.

It is needless to say that the present invention is not limited to the above-described example of the embodiment, and can be carried out in variously modified forms without departing from the scope of the invention, in addition to the above-described example of the embodiment.

10 Vehicle Target Calculation Unit 12 IWM Command Device 16 Abnormality Detector 20L2 Left Second Drive Motor 20L1 Left First Drive Motor 20R1 Right First Drive Motor 20R2 Right Second Drive Motor 22L Left Rear Wheel 22R Right Rear Wheel 30 Vehicle 100 Vehicle Control apparatus

Claims (2)

Left and right independent drive that drives either the front wheels or the rear wheels, and two drive units provided on each of the left and right sides of the drive wheels for driving the drive wheels,
A vehicle target setting unit that sets a target longitudinal force sum and a target yaw moment of the vehicle;
An abnormality detection unit for detecting an abnormality of the drive unit,
An abnormal drive unit in which an abnormality is detected when a torque command based on the target longitudinal force sum and the target yaw moment is instructed to the drive unit and the abnormality detection unit detects an abnormality in any of the drive units. When the required torque for the normal drive unit that drives the same drive wheels as the abnormal drive unit exceeds the rated torque of the normal drive unit, the required torque becomes equal to or less than the rated torque. A drive command unit for setting the torque command,
A vehicle control device comprising: The drive command unit transmits a command of a required torque relating to transient control requiring responsiveness and a command of a required torque having a minute fluctuation to a drive unit provided outside in the vehicle width direction with a constant torque with a small change amount. The vehicle control device according to claim 1, wherein the command of the required torque according to (1) is input to each of the drive units provided on the inner side in the vehicle width direction.