JP2015192471A - vehicle motion control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the disorder of a vehicle behavior at a time of the fall of one wheel during travel.SOLUTION: A vehicle motion control device A1 comprises a drive controlling controller 3 independently controlling torques of right and left driving wheels of at least either front or rear wheels. This vehicle motion control device A1 comprises right and left motor controllers/inverters 4, 6 each exerting a number-of-revolutions feedback control to control an actual number of revolutions of the right or left driving wheel to match a target number of revolutions of the right or left driving wheel. The right and left motor controllers-inverters 4, 6 include reference number-of-revolutions arithmetic units 4b, 6b each calculating an average value of the actual number of revolutions of the right or left driving wheel and computing a reference number of revolutions; right and left difference number-of-revolutions arithmetic units 4c, 6c each computing a deviation of right or left number of revolutions that is a difference in the number of revolutions of the right or left driving wheel from the reference number of revolutions by use of a steering angle so as to provide a right or left difference number of revolutions in response to a tire steering angle; and driving-wheel target number-of-revolutions setting units 4d, 6d, each setting the target number of revolutions of the right or left driving wheel by adding the right or left deviation number of revolutions to the reference number of revolutions.

Description

  The present invention relates to a vehicle motion control device having a configuration for independently controlling the driving force (torque) of at least one of left and right wheels.

  Conventionally, a vehicle attitude stabilization control device having a vehicle attitude control means for generating a disturbance suppression yaw moment amount by a yaw moment generator in a non-steering state for the purpose of stabilizing the vehicle attitude against a crosswind disturbance or a road surface disturbance. Is known (see, for example, Patent Document 1). The disturbance suppression yaw moment amount is obtained based on the detected yaw moment amount.

Japanese Patent Laid-Open No. 2002-212380

  However, in the conventional vehicle attitude stabilization control device, the control of suppressing the yaw moment amount due to the disturbance is performed by the generation of the disturbance suppressing yaw moment amount by the right / left distribution control of the torque. For this reason, if one of the left and right drive wheels fails, there is a problem that the torque control on the one wheel that has failed cannot be performed, and the vehicle behavior may be greatly disturbed.

  The present invention has been made paying attention to the above-described problem, and an object of the present invention is to provide a vehicle motion control device that can suppress disturbance of vehicle behavior when one wheel fails during traveling.

In order to achieve the above object, the present invention includes drive control means for independently controlling the torque of at least one of the front and rear wheels.
In this vehicle motion control device, there is provided drive wheel rotation speed control means for performing rotation speed feedback control for matching the actual rotation speed of each of the left and right drive wheels with the target drive wheel rotation speed of each of the left and right drive wheels.
The drive wheel rotation speed control means includes a reference rotation speed calculation unit, a left / right difference rotation speed calculation unit, and a target drive wheel rotation speed setting unit.
The reference rotation speed calculation unit calculates a reference rotation speed by taking an average value of the actual rotation speeds of the left and right drive wheels.
The left / right difference rotation speed calculation unit uses a steering angle so as to obtain a left / right difference rotation speed according to a tire turning angle, and a right deviation rotation speed that is a rotation speed difference of a right drive wheel with respect to the reference rotation speed, A left deviation rotational speed, which is a rotational speed difference of the left driving wheel with respect to the reference rotational speed, is calculated.
The target drive wheel rotation speed setting unit sets the right target drive wheel rotation speed by adding the right deviation rotation speed to the reference rotation speed, and adds the left deviation rotation speed to the reference rotation speed to set the left target drive wheel Set the rotation speed.

Therefore, the right target drive wheel rotation speed and the left target drive wheel rotation speed are such that the average value of the left and right drive wheels becomes the reference rotation speed, and the target rotation speed difference of the left and right drive wheels becomes the left and right difference rotation speed depending on the steering angle. Is set. Then, the rotational speed feedback control is performed so that the actual rotational speeds of the right driving wheel and the left driving wheel respectively match the right target driving wheel rotational speed and the left target driving wheel rotational speed.
For example, when one wheel fails during driving and the wheel speed (= actual rotation speed) of the failed drive wheel decreases, the wheel speed of the failed drive wheel with respect to the normal drive wheel speed is reduced. As a result of the decrease, the wheel speed divergence width, which is the difference between the left and right driving wheel speeds, is increased, resulting in disturbance of vehicle behavior.
On the other hand, when one wheel falls during traveling and the rotational speed of the failed drive wheel decreases, the average value (= reference rotational speed) of the actual rotational speed of the left and right drive wheels decreases. When this reference rotational speed decreases, the target rotational speed of normal drive wheels decreases as the reference rotational speed decreases, and the rotational speed feedback control is performed to match the actual rotational speed with the target rotational speed. The actual rotational speed on the drive wheel side decreases as the target rotational speed decreases. For this reason, the wheel speed on the normal drive wheel side also decreases along with the decrease in the wheel speed on the failed drive wheel side, and the increase in the wheel speed deviation width is suppressed.
As a result, it is possible to suppress the disturbance of the vehicle behavior when one wheel is lost during traveling.

1 is an overall block configuration diagram illustrating a vehicle motion control device according to a first embodiment. It is a block diagram which shows the calculation processing structure of the target drive wheel rotational speed and target torque of a left-right drive wheel in the vehicle motion control apparatus of Example 1. FIG. 6 is a flowchart illustrating a flow of a calculation process of a left / right differential rotation speed according to a steering angle in a left / right differential rotation speed calculation unit in the vehicle motion control device of the first embodiment. 6 is a flowchart showing a flow of a calculation process of a front / rear deviation rotational speed limit value corresponding to an allowable slip ratio in a front / rear deviation rotational speed limiter in the vehicle motion control device of the first embodiment. It is a flowchart which shows the flow of a calculation process of the right side torque command value (FB part) in the right motor controller & inverter in the vehicle motion control apparatus of Example 1. It is a flowchart which shows the flow of the calculation process of the right side total torque command value in the right motor controller & inverter and drive control controller in the vehicle motion control apparatus of Example 1. It is wheel speed effect | action explanatory drawing which shows the wheel speed of the left driven wheel, the left drive wheel, the right driven wheel, and the right drive wheel in the straight drive state in the in-wheel motor electric vehicle carrying the vehicle motion control apparatus of Example 1. Wheel speed indicating the wheel speed increase / decrease direction of the left driven wheel, the left driving wheel, the right driven wheel, and the right driving wheel when the vehicle moves to the one-wheel failure state in the in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment. FIG. In the in-wheel motor electric vehicle equipped with the vehicle motion control apparatus of the first embodiment, the right front and rear wheel speed, the left front and rear wheel speed, the left and right differential rotation speed command (steering angle), the left torque, the right torque when the left wheel fails It is a timing chart which shows each characteristic of vehicle yaw behavior. Right and left front wheel speed, left front and rear wheel speed, left and right differential rotation speed command (steering angle), left torque, right torque, vehicle when an external disturbance is input in the in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment It is a timing chart which shows each characteristic of yaw behavior. Right and left front wheel speed, left front and rear wheel speed, left and right differential rotation speed command (steering angle), left torque, right torque, vehicle yaw when steering right in an in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment It is a timing chart which shows each characteristic of behavior. In the in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment, the right front / rear wheel speed, the left front / rear wheel speed, and the left / right difference rotational speed command (steering angle) when acceleration / deceleration (uphill / downhill) intervenes during turning. -It is a timing chart which shows each characteristic of left torque, right torque, and vehicle yaw behavior. In the in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment, the right front / rear wheel speed, the left front / rear wheel speed, and the left / right difference rotational speed command (steering angle) when turning right with the front / rear deviation rotational speed limitation. -It is a timing chart which shows each characteristic of left torque, right torque, and vehicle yaw behavior. In the in-wheel motor electric vehicle equipped with the vehicle motion control device of the first embodiment, the right and left wheel speeds, the left and right wheel speeds, the left and right wheel speed commands (steering angle) and the left when the differential gain is increased and the vehicle turns to the right It is a timing chart which shows each characteristic of torque, right torque, and vehicle yaw behavior. It is a block block diagram which shows the right in-wheel motor side structure of the vehicle motion control apparatus of Example 2.

  Hereinafter, the best mode for realizing a vehicle motion control device of the present invention will be described based on Example 1 and Example 2 shown in the drawings.

First, the configuration will be described.
The configuration of the vehicle motion control apparatus according to the first embodiment includes the following: [Overall system configuration], [Calculation processing configuration for left / right differential rotation speed], [Calculation processing configuration for front / rear deviation rotational speed limit value], [Calculation processing for right torque command value] [Configuration], [Right-side total torque command value calculation processing configuration]

[Overall system configuration]
FIG. 1 shows an overall block configuration of the vehicle motion control device A1 of the first embodiment, and FIG. 2 shows a calculation processing configuration of target drive wheel rotational speeds and target torques of left and right drive wheels. The overall system configuration will be described below with reference to FIGS.

  The vehicle motion control device A1 according to the first embodiment uses a rear wheel drive base in which the left and right front wheels are driven wheels, the left and right rear wheels are in-wheel motor drive wheels, and the torque of the left and right rear wheels as drive wheels is independently controlled. It is applied to wheel motor electric vehicles.

  As shown in FIG. 1, the vehicle motion control device A1 includes a steering angle sensor 1, each sensor 2, a drive control controller 3, and a VDC controller 8 as a common configuration for the left and right rear wheels. The right rear wheel side includes a right motor controller & inverter 4 and a right in-wheel motor 5, and the left rear wheel side includes a left motor controller & inverter 6 and a left in-wheel motor 7. Yes.

  The steering angle sensor 1 detects a steering angle by a driver operation on the steering wheel.

  Each of the sensors 2 is a sensor that detects drive control necessary information to the drive control controller 3, and refers to, for example, an accelerator opening sensor, a brake operation amount sensor, a vehicle speed sensor, and the like.

  The drive controller 3 includes an acceleration / deceleration torque calculator 3a, a component protection torque limiter 3b, a select low unit 3c, and a torque limit value calculator 3d.

  The acceleration / deceleration torque calculation unit 3a calculates acceleration / deceleration torque based on input information from each sensor 2 and a torque map. Specifically, acceleration / deceleration torque is calculated based on the motor torque map, the accelerator opening, and the vehicle speed (rotation speed).

  The component protection torque limiting unit 3b calculates a torque limit value that protects each component LBC (lithium battery controller) / INV (inverter) / MG (motor generator) constituting the drive / regeneration control system.

  The select row unit 3c selects the strictest limit value among the torque limit values of the components LBC / INV / MG constituting the drive / regenerative control system. This select row unit 3c inputs a VDC / TCS request from the VDC controller 8 that controls the vehicle behavior by independent braking / driving force control for each wheel, and the VDC / TCS request is a torque limit value of each component LBC / INV / MG. To consider.

  The torque limit value calculation unit 3d sets the limit value selected by the select low unit 3c as the final torque limit value. At this time, the acceleration / deceleration torque from the acceleration / deceleration torque calculation unit 3a is considered.

  The right motor controller & inverter 4 has a combined unit configuration of a right motor controller and a right inverter. The right motor controller & inverter 4 includes a left / right IWM rotation number detection unit 4a, a reference rotation number calculation unit 4b, a left / right difference rotation number calculation unit 4c, a right target drive wheel rotation number setting unit 4d, and a front / rear deviation rotation. A number limiting unit 4e. Furthermore, it has FB torque calculation part 4f, target torque calculation part 4g, torque limiting part 4h, and right IWM current control part 4i.

  The left / right IWM rotational speed detection unit 4a detects the actual rotational speeds of the right in-wheel motor 5 and the left in-wheel motor 7 by a resolver or an ABS wheel speed sensor.

  The reference rotational speed calculation unit 4b calculates the reference rotational speed by taking an average value of the actual rotational speeds of the right in-wheel motor 5 and the left in-wheel motor 7.

  The left / right differential rotation speed calculation unit 4c uses the steering angle information from the steering angle sensor 1 so that the left / right differential rotation speed corresponds to the tire steering angle of the left and right front wheels, and the front wheel steering direction and front wheel steering. The left / right differential rotation speed of the left rear wheel and the right rear wheel according to the angle is calculated. The calculation configuration of the left / right rotational speed will be described later with reference to FIG.

  The right target drive wheel rotational speed setting unit 4d sets the right target drive wheel rotational speed of the rear wheel to a value obtained by adding the right deviation rotational speed (± left-right differential rotational speed / 2) to the reference rotational speed. In other words, the right deviation rotation speed that becomes the inner turning wheel when turning right is given as a negative value corresponding to the reference rotation speed, and the right deviation rotation speed that becomes the outer turning wheel when turning left corresponds to the reference rotation speed. Given as a positive value.

  The front / rear deviation rotational speed limiting unit 4e determines a front / rear deviation rotational speed limit value based on the same driven wheel speed on the right side so that the slip ratio of the right drive wheel that can be generated by the tire transmission torque does not exceed the allowable slip ratio. The right target drive wheel rotational speed of the rear wheel is limited by the front / rear deviation rotational speed limit value. The calculation configuration of the front / rear deviation rotational speed limit value will be described later with reference to FIG.

  The FB torque calculation unit 4f performs feedback control so that the actual rotational speed of the right in-wheel motor 5 matches the right target drive wheel rotational speed of the rear wheel limited by the front-rear deviation rotational speed limit value. (Hereinafter, “right torque command value”) is calculated. The calculation configuration for the right torque command value FB will be described later with reference to FIG.

  The target torque calculation unit 4g adds the right torque command value FB from the FB torque calculation unit 4e to the acceleration / deceleration torque calculated by the acceleration / deceleration torque calculation unit 3a of the drive controller 3, and is generated at the right rear wheel. Target torque (hereinafter, “right total torque command value”) is calculated.

  The torque limiter 4h limits the right total torque command value from the target torque calculator 4g with the final torque limit value from the torque limit value calculator 3d.

  The right IWM current control unit 4i generates a three-phase AC current waveform based on the right total torque command value limited by the final torque limit value by the torque limit unit 4h, and applies it to the right in-wheel motor 5. .

  The left motor controller & inverter 6 has a combined unit configuration of a left motor controller and a left inverter. The left motor controller & inverter 4 is configured in the same manner as the right motor controller & inverter 4. The left motor controller & inverter 6 includes a left / right IWM rotation number detection unit 6a, a reference rotation number calculation unit 6b, a left / right difference rotation number calculation unit 6c, a left target drive wheel rotation number setting unit 6d, and a front / rear deviation. A rotation speed limiter 6e. Furthermore, it has FB torque calculation part 6f, target torque calculation part 6g, torque limiting part 6h, and left IWM current control part 6i. These constituent elements are different from each other on the right or left, and are the same as the corresponding constituent elements of the right motor controller & inverter 4, and thus the description thereof is omitted.

  Next, based on FIG. 2, the calculation processing configuration of the target drive wheel rotational speed and the target torque of the left and right drive wheels will be described with reference to FIG. However, the description will be made by omitting the limitation due to the allowable slip of the target drive wheel speed and the limitation due to the maximum allowable torque of the target torque.

  The left and right IWM rotation speed detectors 4a and 6a are configured by an actual rotation speed (drive wheel) detection section and an opposite rotation speed (drive wheel) detection section.

The reference rotation speed calculation units 4b and 6a determine the reference rotation speed,
Reference rotation speed = (actual rotation speed + reverse rotation speed) / 2
It calculates using the formula of

  For example, the right target drive wheel rotation speed setting unit 4d sets the right target drive wheel rotation speed to a right deviation rotation speed (= −left / right differential rotation speed / 2) as a negative value from the reference rotation speed during right steering. Set by adding. Then, the FB torque calculation unit 4f calculates a right torque command value when feedback control is performed so that the actual rotation speed of the right in-wheel motor 5 matches the right target drive wheel rotation speed.

  The left target drive wheel rotational speed setting unit 6d, for example, sets the left target drive wheel rotational speed to the left deviation rotational speed (= + left / right differential rotational speed / 2) as a positive value from the reference rotational speed during right steering. Set by adding. Then, the FB torque calculation unit 6f calculates a left torque command value for feedback control so that the actual rotation speed of the left in-wheel motor 7 matches the left target drive wheel rotation speed.

  The target torque calculation units 4g and 6g add the right torque command value and the left torque command value from the FB torque calculation units 4f and 6f to the acceleration / deceleration torque calculated by the acceleration / deceleration torque calculation unit 3a, respectively. A torque command value and a left total torque command value are respectively calculated.

  The right IWM current control unit 4i drives the right in-wheel motor 5 by a three-phase AC to obtain a right total torque command value, and the left IWM current control unit 6i has a left-in by a three-phase AC to obtain a left total torque command value. The wheel motor 7 is driven.

  That is, at the time of steering 0: left-right differential rotation speed = 0, right wheel target rotation speed = constant (= reference rotation speed), left wheel target rotation speed = constant (= reference rotation speed). Right steering: right / left differential rotation speed = increase, right wheel target rotation speed = decrease (= reference rotation speed-left / right differential rotation speed / 2), left wheel target rotation speed = increase (= reference rotation speed + left / right differential rotation speed / 2) Left steering: left / right differential speed = decrease, right wheel target speed = increase (= reference speed + left / right differential speed / 2), left wheel target speed = decrease (= reference speed-left / right differential speed / 2)

[Calculation of left / right differential rotation speed]
FIG. 3 shows the flow of the calculation process of the left / right differential rotation speed according to the steering angle in the left / right differential rotation speed calculation units 4c, 6c. Hereinafter, based on FIG. 3, the calculation processing configuration of the left / right differential rotation speed will be described.

  In step S31, based on the sensor signal from the rudder angle sensor 1, it is determined whether steering is present or steering is zero. If the steering is zero, the process proceeds to step S32, where the left / right rotational speed command = 0.

  In step S33, following the determination that steering is present in step S31, the steering angle is divided by the steering gear ratio to calculate the tire turning angle (δ) of the front wheels, and the process proceeds to step S34.

In step S34, following the calculation of the tire turning angle (δ) of the front wheels in step S33, the turning radius R is calculated using the tire turning angle δ of the front wheels and the wheelbase L.
R = L / sin (δ)
And the process proceeds to step S35. Here, the calculation formula aiming at the neutral steer characteristic is shown as the steer characteristic, but it is also possible to match the characteristic of the base vehicle or the over steer characteristic / under steer characteristic.

In step S35, following the calculation of the turning radius R in step S34, the inner ring turning radius (Rin) and the outer ring turning radius (Rout) are calculated using the turning radius R and the drive wheel tread length.
Rin = R-drive wheel tread length / 2
Rout = R + Drive wheel tread length / 2
And the process proceeds to step S36.

In step S36, following the calculation of the inner ring turning radius (Rin) and the outer ring turning radius (Rout) in step S35, the speed difference (Vout−Vin) between the inner ring speed (Vin) and the outer ring speed (Vout) is calculated as follows:
Vout−Vin = Rout × ω−Rin × ω = (Rout−Rin) × (vehicle speed / R)
= Drive wheel tread length x (vehicle speed / R)
In the case of right steering, the process proceeds to step S37, and in the case of left steering, the process proceeds to step S38.

  In step S37, following the determination that the steering is rightward, the left-right differential rotational speed command = (Vout−Vin) is converted into the left-right differential rotational speed to obtain the left-right differential rotational speed according to the steering angle during right steering.

  In step S38, following the determination of left steering, the left / right differential rotation speed command = − (Vout−Vin) is converted into a left / right differential rotation speed to obtain a left / right differential rotation speed corresponding to the steering angle during left steering. .

[Computation configuration of front / rear deviation rotation speed limit value]
FIG. 4 shows the flow of the calculation process of the front / rear deviation rotational speed limit value according to the allowable slip ratio in the front / rear deviation rotational speed limiters 4e, 6e. Hereinafter, based on FIG. 4, the calculation processing configuration of the front / rear deviation rotational speed limit value will be described.

  In step S41, the required lateral G is calculated based on the selected high of the current lateral G sensor value and the lateral G estimated from the steering amount and the vehicle speed, and the process proceeds to step S42.

  In step S42, following the calculation of the required lateral G in step S41, the required lateral G is converted into the required lateral force by the vehicle specifications, and the process proceeds to step S44.

In step S44, based on the required lateral force from step S42 and the slip ratio-tire maximum lateral force map described in the frame of step S43, an allowable slip ratio for generating the required lateral force is calculated, Proceed to step S45.
Here, the allowable slip ratio is calculated as a slip ratio (a value in which the allowable slip is suppressed) with a smaller value as the required lateral force increases.

In step S45, following the calculation of the allowable slip ratio in step S44, the front / rear deviation rotational speed limit value (= front / rear deviation wheel speed limit value) is
Front / rear deviation rotational speed limit value = driven wheel speed (considered as ground vehicle speed) ± driven wheel speed × allowable slip ratio.
Here, as the driven wheel speed, the wheel speed of the same right driven wheel is used on the right drive wheel side, and the wheel speed of the same left driven wheel is used on the left drive wheel side.

[Right Torque Command Value Calculation Processing Configuration]
FIG. 5 shows the flow of processing for calculating the right torque command value (for FB) in the right motor controller & inverter 4. Hereinafter, the calculation processing configuration of the right torque command value will be described with reference to FIG. Here, the right side process after inputting the target left / right difference rotation speed calculated by the left / right difference rotation speed calculation units 4c, 6c using the steering angle value from the steering angle sensor 1 will be described. Note that the left-side process is the same as the right-side process, and a description thereof will be omitted.

In step S51, the right target drive wheel rotational speed is
Right target drive wheel speed = reference speed + target left / right differential speed (= right deviation speed)
The process proceeds to step S52.

  In step S52, following the right target drive wheel rotation speed in step S51, the front / rear deviation rotation speed limiter 4e limits the upper right / lower limit guard process so that the right target drive wheel rotation speed does not exceed the allowable slip ratio, Proceed to step S53.

  In step S53, following the upper / lower limit guard process in step S52, the difference (deviation) between the right target drive wheel speed after the limit and the right actual speed sensor value is calculated, step S54, step S55, step Proceed to S57.

  In step S54, following the difference calculation of the right drive wheel rotation speed in step S53, the P gain (proportional gain) is added to the difference of the right drive wheel rotation speed to calculate the proportional term (P term) of PID control. The process proceeds to step S59.

  In step S55, following the difference calculation of the right drive wheel rotation speed in step S53, an integration process of the difference of the right drive wheel rotation speed is performed. In the next step S56, the I gain (integral gain) is added to the value obtained by integrating the difference, and the integral term (I term) of the PID control is calculated, and the process proceeds to step S59.

  In step S57, following the difference calculation of the right drive wheel rotation speed in step S53, differential processing of the difference in right drive wheel rotation speed is performed. In the next step S58, the D gain (differential gain) is added to the value obtained by differentiating the difference to calculate the differential term (D term) of the PID control, and the process proceeds to step S59. The D gain is given by a variable value corresponding to the steering speed.

  In step S59, the proportional term (P term) from step S54, the integral term (I term) from step S57, and the differential term (D term) from step S58 are added, and the right torque command value (FB Min).

[Right-side total torque command value calculation processing configuration]
FIG. 6 shows a flow of processing for calculating the right total torque command value in the right motor controller & inverter 4 and the drive control controller 3. Hereinafter, the calculation processing configuration of the right total torque command value will be described with reference to FIG.

  In step S61, the acceleration / deceleration torque calculation unit 3a calculates the acceleration / deceleration torque based on the input information from each sensor 2 and the motor torque map (vehicle speed, accelerator opening), and proceeds to step S66.

In step S62, in the right target drive wheel speed setting unit 4d, the target drive wheel speed is set so as to be the difference between the left and right speeds (as intended by the driver).
Right target drive wheel speed = reference speed + target left / right differential speed (= right deviation speed)
The process proceeds to step S63.

In step S63, following the setting of the right target drive wheel speed in step S62, the slip ratio (or slip amount) with respect to the estimated vehicle speed calculated from the driven wheel speed does not exceed the allowable slip ratio (or allowable slip amount). Then, upper and lower limit guards are performed on the right target drive wheel rotation speed (= target vehicle speed), and the process proceeds to step S65.
Here, the upper and lower limit guards, for example, when the allowable slip rate is 3%,
Driven wheel speed x 1.03 (temporary)> Target vehicle speed> Driven wheel speed x 0.97 (temporary)
To do.

  In step S64, the gain of the proportional term (P term) with respect to the left-right differential rotation (difference), the gain of the differential term (D term) with respect to the steering, and the gain of the integral term (I term) due to tire differences are adjusted. In step S65, the adjusted gains are output. Here, the gain of the proportional term (P term) with respect to the left-right differential rotation is set to a larger value as the disturbance stabilization requirement is higher. The gain of the differential term (D term) for steering is set to a larger value as the steering response request is higher.

In step S65, following the setting of the upper and lower limit guards for the right target drive wheel speed in step S63 and the feedback control gain in step S64, PID control is performed so that the target drive wheel speed is obtained in the FB torque calculation unit 4f. The right torque command value is
Right torque command value = P gain × (right target drive wheel rotation speed−right actual rotation speed) + I gain × (right target drive wheel rotation speed−right actual rotation speed) integral value + D gain × (right target drive wheel rotation speed) -Calculated by the equation of the differential value of (the right actual rotational speed), and proceeds to step S66.

  In step S66, following the calculation of the acceleration / deceleration torque in step S61 and the calculation of the right torque command value in step S65, the target torque calculation unit 4g adds the acceleration / deceleration torque and the right torque command value (select high). The right total torque command value is calculated, and the process proceeds to step S68.

In step S67, the torque limit value calculation unit 3d calculates a torque limit value (drive side & regeneration side) for each component LBC / INV / MG constituting the drive / regeneration control system. Then, the strictest limit (a value close to 0) is selected from the torque limit values of each component LBC / INV / MG and set as the final torque limit value. The final torque limit value is
Final torque limit value (drive side) = min (each component torque limit value (drive side))
Final torque limit value (regeneration side) = max (each component torque limit value (regeneration side))
Decide by. The regeneration side torque is negative.

In step S68, the torque limiter 4h uses the final torque limit value (drive side) and the final torque limit value (regeneration side) from step S67, and calculates the right total torque command value from step S66.
Final torque limit value (drive side)> Right total torque command value> Final torque limit value (regenerative side)
To the right total torque command value (after limitation).

  In step S69, the right IWM current control unit 4i outputs a command for obtaining the right total torque command value after the torque limitation in step S68 to the right in-wheel motor 5.

Here, the priority (1) described for the priorities (1) to (4) of each step in FIG. 6 applies torque limitation so as to protect each component LBC / INV / MG in steps S67 and S68. That is. The reason for this is that if any of the parts LBC / INV / MG is broken, motion control cannot be performed, and therefore, part protection is given the highest priority.
The priority (2) is to limit the target drive wheel rotation speed so that the slip in step S63 does not exceed a certain value. The reason is to prevent tire slip. Without this restriction, the following priorities (3) and (4) cannot be controlled as intended.
The priority (3) is to set the target drive wheel rotational speed so that the left / right rotational speed difference intended by the driver in step S62 is obtained. The reason is to ensure vehicle yaw control. Without this, the yaw behavior during turning cannot be stabilized.
The priority (4) is to calculate the acceleration / deceleration torque requested by the driver in step S61. The reason is that it is necessary to ensure normal running performance according to the driver's driving force request and braking force request.

Next, the operation will be described.
The actions in the vehicle motion control apparatus A1 of the first embodiment are [vehicle action stabilizing action when one wheel fails], [vehicle action improving action in various driving modes], [front-rear deviation rotational speed limiting action], [differentiation] A description will be given separately for the "steering response improving effect by increasing gain" and the "torque limiting effect".

[Vehicle behavior stabilization when one wheel fails]
In order to represent vehicle motion, it is necessary to represent the relative relationship between the vehicle coordinate system and the road surface coordinate system. Normally, the vehicle coordinate system motion (yaw rate, etc.) relative to the road surface coordinate system and the apparent acceleration (lateral G) generated in the vehicle coordinate system ) Etc. are used. For this reason, conventionally, the vehicle motion is controlled by a host controller (close to the driver), and the braking / driving actuators (ACT) of each wheel have a role of executing a command value such as a given torque. However, in the conventional configuration, the command value is calculated from each sensor such as the steering angle and the yaw rate, and the actuator is controlled after communicating with the actuator (ACT). Therefore, a response speed such as an improvement in steering response and disturbance stability is required. It is a bottleneck for functionality.

  For example, a vehicle attitude stabilization control device described in Japanese Patent Application Laid-Open No. 2002-212380 is used as a comparative example. In this comparative example, for the purpose of stabilizing the vehicle attitude against crosswinds, road surface disturbances, etc., a disturbance yaw moment is detected and control for generating a disturbance suppression yaw moment is performed. In the case of this comparative example, after determining the vehicle behavior target, it is converted to the actuator command value. However, in the case of an in-wheel motor electric vehicle, arbitration with acceleration / deceleration torque is required when converting to the actuator command value. is there. For this reason, operation becomes impossible when torque control cannot be performed due to the failure of one of the left and right drive wheels. The actuator output torque may behave contrary to the intention depending on the road surface condition or the like.

On the other hand, the present inventors paid attention to the following two points.
(a) In order to represent vehicle motion, a method of representing the vehicle motion with an interface between the vehicle coordinate system and the road surface coordinate system is conceivable. Specifically, it can be represented by the left and right wheel speeds.
(b) Since the in-wheel motor is an actuator that transmits the force to the road surface, the controller is not suitable for vehicle motion control based on the yaw rate or lateral G. However, if the motor speed control is used, its role is minimized. Can be implemented.

  According to the above-mentioned attention points (a) and (b), in the first embodiment, the average value of the left and right drive wheels is set as the reference rotation speed, and the right target drive wheel rotation speed and the left target drive wheel rotation speed are compared with the reference rotation speed. The target rotational speed difference between the left and right drive wheels is set to be the left / right differential rotational speed depending on the steering angle. Then, the rotational speed feedback control is performed in which the actual rotational speeds of the right driving wheel and the left driving wheel are matched with the right target driving wheel rotational speed and the left target driving wheel rotational speed, respectively.

  For example, when one wheel falls during driving and the wheel speed (= actual rotation speed) of the missing drive wheel decreases, the wheel on the drive wheel side that has failed with respect to the wheel speed on the normal drive wheel side Due to the decrease in speed, the wheel speed deviation width, which is the difference between the left and right driving wheel speeds, is increased, resulting in disturbance of vehicle behavior.

  On the other hand, when one wheel falls during traveling and the rotational speed of the failed drive wheel decreases, the average value (= reference rotational speed) of the actual rotational speed of the left and right drive wheels decreases. When this reference rotational speed decreases, the target rotational speed of normal drive wheels decreases as the reference rotational speed decreases, and the rotational speed feedback control is performed to match the actual rotational speed with the target rotational speed. The actual rotational speed on the drive wheel side decreases as the target rotational speed decreases. For this reason, the wheel speed on the normal drive wheel side also decreases along with the decrease in the wheel speed on the failed drive wheel side, and the increase in the wheel speed deviation width is suppressed. As a result, when one wheel fails during traveling, the disturbance of the vehicle behavior can be suppressed, and the stabilization of the vehicle behavior is achieved.

Hereinafter, based on FIG.7 and FIG.8, the wheel speed increase / decrease effect | action when it transfers to a one-wheel failure from a normal straight drive state is demonstrated in detail.
FIG. 7 shows a normal straight traveling state. In a normal straight traveling state in which the left driven wheel rotational speed = the right driven wheel rotational speed, the wheel speed does not increase or decrease. That means
The relationship of left driven wheel rotation speed = left driving wheel actual rotation speed = reference rotation speed right driven wheel rotation speed = right driving wheel actual rotation speed = reference rotation speed is maintained.
When shifting from the normal straight traveling state to the one-wheel failure state (left wheel failure state), as shown in FIG. 8, the left drive wheel actual rotational speed is reduced as compared with the straight traveling due to the left wheel failure. That is, if the left drive wheel actual rotation speed at the time of failure of the left wheel becomes lower than the right drive wheel actual rotation speed, the average rotation speed of the left drive wheel actual rotation speed is equal to the right drive wheel target rotation speed (reference Number of revolutions). Therefore, the wheel speeds of the right driven wheel and the right drive wheel are reduced from the wheel speed when traveling straight toward the right drive wheel target rotation speed (reference rotation speed).
Looking at the yaw behavior of the vehicle, if the left drive wheel actual rotation speed decreases when the left wheel breaks down, a leftward moment acts around the vehicle center of gravity. On the other hand, when the actual rotational speed of the right drive wheel decreases toward the reference rotational speed by the rotational speed control, a rightward moment acts around the vehicle center of gravity. Therefore, the yaw behavior in the left direction due to the left wheel failure is returned by the right yaw behavior by the rotational speed control, and the disturbance of the yaw behavior of the vehicle is alleviated.

  FIG. 9 shows each characteristic when the left wheel fails in the in-wheel motor electric vehicle equipped with the vehicle motion control device A1 of the first embodiment. Hereinafter, based on FIG. 9, the vehicle behavior stabilizing action at the time of one wheel failure (when the left wheel breaks down and the rotational speed is reduced) will be described.

  At the left wheel failure time t1, when the left wheel speed starts to decrease, the reference rotational speed, which is the average value of the actual rotational speeds of the left and right drive wheels, immediately after that, as shown by the broken line characteristic of the arrow B in FIG. To start. When the reference rotational speed starts to decrease, the right / left differential rotational speed is zero, so the right wheel target rotational speed decreases, and the right wheel starts from time t2 slightly delayed from the start of the decrease in the left wheel speed by rotational speed feedback control. The speed starts to drop. Then, both the right wheel speed and the left wheel speed decrease from time t2 to time t3, and when the left wheel speed becomes zero at time t3, the right wheel speed at time t4, which is slightly delayed from the time when the left wheel speed becomes zero. Speed becomes zero.

  Looking at the vehicle yaw behavior, from the left wheel failure time t1 to time t2, it shows an upward change by expanding the deviation width of the left and right wheel speed due to the decrease in the left wheel speed only, but from time t2 to time t3, As both the left and right wheel speeds decrease, the difference between the left and right wheel speeds becomes constant, and the change converges. Furthermore, from time t3 to time t4, the divergence width of the left and right wheel speeds is reduced due to a decrease in only the right wheel speed, and the divergence width becomes zero at time t4, indicating a descending characteristic.

  In this way, when the left wheel speed decreases due to the failure of one wheel (left wheel) during traveling, motor speed control is performed to reduce the right wheel speed of the right wheel, which is normal. Disturbances in vehicle behavior due to enlargement can be suppressed. FIG. 9 shows an example of a single wheel failure in a straight traveling state in which the left / right rotational speed is zero. However, even in the case of a single wheel failure in a turning state where a left / right rotational speed is generated, the control of maintaining the wheel speed difference (= left / right differential speed) for the turning as the wheel speed difference between the left and right wheels, Disturbance can be suppressed.

  On the other hand, when the torque is generated from the failed one wheel at the time of the failure of one wheel, the left-right torque difference contributes to the stabilization of the vehicle behavior. That is, in the rotation speed feedback control, when the target drive wheel rotation speed is higher than the actual rotation speed, the torque is increased so as to increase the actual rotation speed to the target drive wheel rotation speed. Conversely, when the target drive wheel speed is lower than the actual speed, the torque is reduced so as to reduce the actual speed to the target drive wheel speed. Therefore, for the right wheel for which the rotational speed feedback control is normally performed, the right torque starts to decrease at a timing slightly delayed from the left wheel failure time t1 in order to decrease the right wheel speed. For this reason, the left-right torque difference due to the relationship of left torque> right torque increases, and the left-right torque difference becomes maximum at time t4.

  Therefore, if the left wheel speed decreases due to the failure of one wheel (left wheel) during driving, the in-wheel motor electric vehicle generates a yaw moment in the left turn direction, while the left-right torque difference of left torque> right torque. Thus, the yaw moment in the right turn direction can be generated and the yaw moment in the left turn direction can be offset.

[Vehicle behavior improvement effect in various driving modes]
As described above, the problem of the in-wheel motor electric vehicle can be covered such that the yaw behavior can be mitigated by one wheel remaining even when one wheel is lost by controlling the motor rotation speed independently for each wheel. In addition, the left and right in-wheel motors 5 and 7 are independently controlled to give the left / right differential rotation speed based on the steering angle, so that the driver's steering intention is directly transmitted to the road surface. Thereby, disturbance stability improvement, steering response improvement, turning acceleration / deceleration, or stability improvement on a turning up / down slope can be achieved. Hereinafter, the vehicle behavior improving effect in various travel modes will be described with reference to FIGS.

FIG. 10 shows each characteristic when a disturbance is input in the in-wheel motor electric vehicle equipped with the vehicle motion control device A1 of the first embodiment.
For example, when only the left driving wheel rides on the convex road surface from a flat road, the resistance increases and the left wheel speed decreases from time t1. And when it descends from the top surface of the convex road surface, the resistance decreases, the left wheel speed increases, and the vehicle moves to a flat road at time t3. In contrast to the decrease characteristic of the left wheel speed, the right wheel speed exhibits a decrease characteristic of the left wheel speed and an increase characteristic due to line symmetry, and a wheel speed deviation that shifts from expansion to decrease occurs. At the time of this disturbance input, since it is a straight traveling state, as shown by the broken line characteristic of the arrow C in FIG. Then, rotation speed feedback control is performed so that the left and right rotations are the same. By this control, the left torque of the left drive wheel exhibits an increasing characteristic between time t2 and time t4 due to response delay so as to increase the left wheel speed to the target rotational speed. On the other hand, the right torque of the right drive wheel exhibits a decreasing characteristic between time t2 and time t4 due to response delay so as to reduce the right wheel speed to the target rotational speed.
Therefore, when a disturbance is input during driving, an in-wheel motor electric vehicle generates a yaw moment in the left turn direction, while a left-right torque difference of left torque> right torque causes a right turn yaw moment. It is possible to cancel the yaw moment in the left turn direction. As a result, in the disturbance input travel mode, it is possible to improve the disturbance stability only by temporarily changing the vehicle yaw behavior between time t1 and time t3 according to the change in the deviation width of the left and right wheel speeds. it can.

FIG. 11 shows each characteristic when the right steering is performed in the in-wheel motor electric vehicle on which the vehicle motion control device A1 of the first embodiment is mounted.
For example, when right steering is performed from time t1 to time t4, a left-right differential rotation speed command is issued in accordance with right steering. Therefore, the left wheel target rotational speed is increased from time t2 as shown by the broken line characteristic of arrow D in FIG. 11, and the right wheel target rotational speed is increased from time t2 as shown by the broken line characteristic of arrow E in FIG. Be lowered. Therefore, the rotational speed feedback control is performed so that the difference between the left wheel speed and the right wheel speed becomes the right / left differential rotational speed at the time of right steering. By this control, the left torque of the left driving wheel exhibits an increasing characteristic between time t2 and time t7 due to response delay so as to increase the left wheel speed to the target rotational speed. On the other hand, the right torque of the right drive wheel shows a decreasing characteristic between time t2 and time t7 due to response delay so as to lower the right wheel speed to the target rotational speed.
Therefore, at the time of right steering, from time t3 to time t5, the wheel speed deviation increases due to the relationship of left wheel speed> right wheel speed, and a yaw moment in the right turn direction is generated in the in-wheel motor electric vehicle. In addition, from time t2 to time t7, there is a left-right torque difference of left torque> right torque, and a yaw moment in the right turn direction is generated. Then, the vehicle yaw behavior changes in the right turn direction from time t4 to time t6. As described above, in the turning mode by the right steering, it is possible to improve the steering responsiveness by encouraging the change in the yaw behavior in the right turning direction due to the synergistic effect of the wheel speed deviation and the left-right torque difference. .

FIG. 12 shows each characteristic when acceleration / deceleration (uphill / downhill) is performed during a right turn in the in-wheel motor electric vehicle equipped with the vehicle motion control device A1 of the first embodiment.
When acceleration / deceleration (uphill / downhill) occurs during a right turn, the left wheel speed decreases and the right wheel speed increases during time t1 to time t3 due to acceleration / deceleration or uphill / downhill. At this acceleration / deceleration or uphill / downhill, the vehicle is turning (right turning) as in FIG. 11, so the left wheel target rotational speed is constant at a high value as shown by the broken line characteristic of the arrow D in FIG. The right wheel target rotational speed is constant at a low value as shown by the broken line characteristic of arrow E in FIG. 12, and the rotational speed feedback control is performed so that the left wheel speed and the right wheel speed become the respective target rotational speeds. Is called. By this control, the left torque of the left drive wheel exhibits an increasing characteristic between time t2 and time t4 due to response delay so as to increase the left wheel speed to the target rotational speed. On the other hand, the right torque of the right drive wheel exhibits a decreasing characteristic between time t2 and time t4 due to response delay so as to reduce the right wheel speed to the target rotational speed.
Thus, during acceleration, when an acceleration / deceleration (uphill / downhill) in which the left wheel speed decreases and the right wheel speed increases increases, the in-wheel motor electric vehicle temporarily turns to the left due to a change in the wheel speed difference. Generates a yaw moment in the direction. On the other hand, the yaw moment in the right turn direction can be temporarily generated by the left-right torque difference of left torque> right torque, and the yaw moment in the left turn direction can be offset. As a result, in the turning mode in which acceleration / deceleration (uphill / downhill) intervenes, as shown in the vehicle yaw behavior characteristics, changes in yaw behavior are suppressed without being affected by acceleration / deceleration or uphill / downhill. The stability on the slope can be improved.

[Front-rear deviation rotational speed limiting action]
In the first embodiment, the front / rear deviation rotational speed limit value is determined based on the driven wheel speed on the same left and right side so that the slip ratio of the left and right drive wheels that can be generated by the tire transmission torque does not exceed the allowable slip ratio. And it was set as the structure which has the front-and-rear deviation rotational speed restriction | limiting parts 4e and 6e which restrict | limit each of the right target drive wheel rotational speed and the left target drive wheel rotational speed by the front-rear deviation rotational speed restriction value.

  In other words, in calculating the target drive wheel speed, the deviation from the driven wheel speed (ground vehicle speed) is limited by the allowable slip rate, so that a decrease in lateral force due to slippage (idling) of the left and right drive wheels is prevented. . Hereinafter, the front / rear deviation rotational speed limiting action will be described with reference to FIG. 13 showing respective characteristics when an in-wheel motor electric vehicle equipped with the vehicle motion control device A1 is turned to the right with the front / rear rotational speed limitation.

  For example, when right steering is performed from time t1 to time t4 on a low μ road, a left / right differential rotation speed command is issued in accordance with right steering. Therefore, the left wheel target rotation speed is increased from time t3 as shown by the broken line characteristic of the arrow D in FIG. 13, but the increase width is suppressed to the solid line characteristic of the arrow D ′ in FIG. The right wheel target rotational speed is lowered from time t3 as shown by the broken line characteristic of arrow E in FIG. 13, but the descending width is suppressed to the solid line characteristic of arrow E 'in FIG. Therefore, the rotational speed feedback control is performed so that the difference between the left wheel speed and the right wheel speed becomes the left / right differential rotational speed at the time of right steering limited by the front / rear deviation rotational speed. By this control, the left torque of the left drive wheel exhibits an increasing characteristic between time t2 and time t7 due to response delay so as to increase the left wheel speed to a target rotational speed without slipping. On the other hand, the right torque of the right drive wheel shows a decreasing characteristic between time t2 and time t7 due to response delay so as to lower the right wheel speed to a target rotational speed without slipping.

Therefore, when it is not limited by the front / rear deviation rotational speed, the vehicle yaw behavior changes in the right turn direction from time t4 to time t6, as shown by the vehicle yaw behavior broken line characteristic in FIG. On the other hand, when limited by the front / rear deviation rotational speed, as shown in the vehicle yaw behavior solid line characteristic in FIG. 13, the left and right drive wheels exert lateral force in the grip state, and the time t4- The vehicle yaw behavior changes in the right turn direction until time t5.
As a result, during turning, the stability of turning behavior can be secured by the road surface grip of the tire, and the steering response can be improved by preventing the lateral force of the left and right driving wheels from being lowered.

In Example 1, the allowable slip ratio for generating the tire lateral force necessary for turning is calculated, and the longitudinal deviation rotational speed limit value is set to a value that increases or decreases in accordance with the allowable slip ratio.
That is, the front-rear deviation rotational speed limit value is given as a variable value in accordance with the allowable slip ratio for generating the necessary lateral force during turning.
Therefore, as in the case where the front / rear deviation rotational speed limit value is given as a constant value, the excessive limit or insufficient limit on the allowable slip rate is resolved, and the turning behavior is stable regardless of the road surface, the turning vehicle speed, the turning amount, etc. It is possible to ensure safety and improve steering response.

[Improvement of steering response by increasing differential gain]
In the first embodiment, the right torque command value and the left torque command value are calculated by feedback control having a differential term based on the differential gain and the deviation differential value based on the deviation between the target drive wheel rotation speed and the actual rotation speed of the left and right drive wheels. FB torque calculation units 4f and 6f are provided. The FB torque calculation units 4f and 6f are configured to adjust the differential gain of the differential term to a larger value as the steering speed is higher.

  That is, the higher the steering speed by the driver, the higher the response speed of the rotational speed feedback control. Hereinafter, the steering response improvement effect by increasing the differential gain will be described based on FIG. 14 showing respective characteristics when the differential gain is increased and the vehicle turns right in an in-wheel motor electric vehicle equipped with the vehicle motion control device A1.

  For example, if right steering is performed at time t1, a left / right differential rotation speed command is issued. Therefore, the left wheel target rotation speed and the right wheel target rotation speed start to change due to rising and falling from time t2, as indicated by the broken line characteristics of arrows D and E in FIG. At this time, if the differential gain of the rotational speed feedback control is given as a constant value, the actual rotational speed of the left and right wheels starts to change due to the rise and fall along the target characteristics indicated by the broken line from the response delay timing after time t4. . On the other hand, if the differential gain of the rotational speed feedback control is given as an increased value, the actual rotational speed of the left and right wheels starts to change due to the rise and fall with a steep slope from the target characteristic indicated by the broken line from the timing of time t3. To do. Therefore, the left torque and the right torque of the left drive wheel show an increase characteristic and a decrease characteristic between time t2 and time t5.

Therefore, when the differential gain is given as a constant value, the vehicle yaw behavior changes in the right turn direction until time t7 as shown in the vehicle yaw behavior broken line characteristic of FIG. On the other hand, when the differential gain is given as an increased value, the vehicle yaw behavior changes in the right turn direction from time t4 to time t5 as shown by the solid line characteristics of the vehicle yaw behavior in FIG.
As a result, when turning at a high steering speed, the difference between the left and right torques is generated early, so the difference between the left and right rotational speeds is also realized early, and the convergence of the left and right torque differences is accelerated. Improvements can be made.

[Torque limiting action]
In the first embodiment, a torque limit value that protects each component LBC / INV / MG constituting the drive / regenerative control system is calculated, and the strictest limit value (= final value) among the torque limit values of each component LBC / INV / MG is calculated. Torque limit value) is selected. Then, the right total torque command value and the left total torque command value are subjected to limit processing by the final torque limit value (drive side, regeneration side), and the total torque command value after the limit processing is output to the left and right in-wheel motors 5 and 7. It was set as the structure to do.
For example, if any of the parts LBC / INV / MG constituting the drive / regeneration control system is broken, the rotational speed feedback control of the present application cannot be performed. On the other hand, by limiting the actuator output torque with the strictest limit value among the torque limit values of each component LBC / INV / MG, each component LBC / INV / MG constituting the drive / regenerative control system is protected from damage. Protected.
Therefore, by protecting each component LBC / INV / MG constituting the drive / regenerative control system, it is possible to guarantee the normal rotation speed feedback control that stabilizes the vehicle behavior.

Next, the effect will be described.
In the vehicle motion control device A1 of the first embodiment, the effects listed below can be obtained.

(1) In the vehicle motion control device A1 provided with drive control means (drive control controller 3) for independently controlling the torque of the left and right drive wheels of at least one of the front and rear wheels,
Driving wheel rotational speed control means (right motor controller & inverter 4, left motor controller & inverter) that performs rotational speed feedback control to match the actual rotational speed of each of the left and right driving wheels with the respective target driving wheel rotational speed of the left and right driving wheels 6)
Drive wheel rotation speed control means (right motor controller & inverter 4, left motor controller & inverter 6) takes a mean value of the actual rotation speeds of the left and right drive wheels and calculates a reference rotation speed calculation unit 4b. , 6b,
Using the steering angle so that the left / right differential rotation speed corresponds to the tire turning angle, the right deviation rotation speed, which is the rotation speed difference of the right drive wheel with respect to the reference rotation speed, and the rotation speed difference of the left drive wheel with respect to the reference rotation speed Left and right differential rotation speed calculation units 4c and 6c for calculating the left deviation rotation speed,
A target drive wheel speed setting unit 4d for setting the right target drive wheel speed by adding the right deviation speed to the reference speed and setting the left target drive wheel speed by adding the left deviation speed to the reference speed; 6d (FIG. 1).
For this reason, when one wheel falls during driving | running | working, disorder of a vehicle behavior can be suppressed.

(2) The drive wheel speed control means (right motor controller & inverter 4, left motor controller & inverter 6) has a slip (slip ratio) that can be generated by the tire transmission torque. Therefore, the right and left deviation rotation speed limit values are determined based on the driven wheel speeds on the left and right sides, and the right target drive wheel rotation speed and the left target drive wheel rotation speed are limited by the front and rear deviation rotation speed limit values. The front and rear deviation rotational speed limiters 4e and 6e are provided (FIG. 4).
Therefore, in addition to the effect of (1), when turning, it is possible to ensure the stability of turning behavior by the road surface grip of the tire, and to improve the steering response by preventing the lateral force of the left and right drive wheels from decreasing. it can.

(3) The front / rear deviation rotational speed limiters 4e and 6e calculate an allowable slip value (allowable slip ratio) for generating the tire lateral force required for turning, and the front / rear deviation rotational speed limit value is calculated as the allowable slip value. The value was increased or decreased according to (allowable slip ratio) (FIG. 4).
For this reason, in addition to the effect of (2), it is possible to ensure the stability of turning behavior and improve the steering responsiveness irrespective of the turning state due to the road surface state, the turning vehicle speed, the steering amount, or the like.

(4) The drive wheel speed control means (right motor controller & inverter 4, left motor controller & inverter 6) is based on the difference between the target drive wheel speed and the actual speed of the left and right drive wheels, and the differential gain and deviation differential value. FB torque calculation unit 4f that calculates a right torque command value and a left torque command value by feedback control having a derivative term by
The FB torque calculation unit 4f adjusts the differential gain of the differential term so that it increases as the steering speed increases (FIG. 5).
For this reason, in addition to the effects of (1) to (3), when turning at a high steering speed, the steering responsiveness in response to the driver's request is improved so that the yaw behavior converges quickly due to the difference in the left and right torque. be able to.

(5) The drive control means (drive control controller 3) includes a component protection torque limiter 3b for calculating a torque limit value for protecting each component LBC / INV / MG constituting the drive / regeneration control system;
A select row unit 3c for selecting the strictest limit value among the torque limit values of each component LBC / INV / MG,
A torque limit value calculation unit 3d having the selected limit value as a final torque limit value,
The drive wheel speed control means (right motor controller & inverter 4, left motor controller & inverter 6) calculates the right total torque command value and the left total torque command value from the target torque calculation units 4g and 6g according to the final torque limit value. Torque limiting portions 4h and 6h for limiting are provided (FIG. 6).
For this reason, in addition to the effects of (1) to (4), normal speed feedback control that stabilizes vehicle behavior is realized by protecting each component LBC / INV / MG that constitutes the drive / regenerative control system. Can be guaranteed.

  The second embodiment is an example in which the reference rotational speed is calculated by converting the target vehicle speed from the accelerator opening.

First, the configuration will be described.
FIG. 15 illustrates a right in-wheel motor side configuration of the vehicle motion control device A2 of the second embodiment. Hereinafter, the right in-wheel motor side configuration will be described with reference to FIG.

  As shown in FIG. 14, the vehicle motion control device A <b> 2 of the second embodiment includes a steering angle sensor 1, each sensor 2, a drive control controller 3, a right motor controller & inverter 4, a right in-wheel motor 5, It has.

  The drive control controller 3 includes a target vehicle speed calculation unit 3e that calculates a target vehicle speed according to the accelerator opening. The target vehicle speed is obtained by drawing a map using an accelerator opening / target vehicle speed map as shown in the frame of the target vehicle speed calculation unit 3e. Specifically, the vehicle speed proportionally increased as the accelerator opening is increased is calculated as the target vehicle speed.

  As shown in FIG. 15, the right motor controller & inverter 4 includes a reference rotation speed calculation unit 4j, a left / right difference rotation speed calculation unit 4c, a right target drive wheel rotation speed setting unit 4d, and a right IWM current control unit 4i. And having. That is, the configuration related to torque calculation processing such as the FB torque calculation unit 4f, the target torque calculation unit 4g, and the torque limiting unit 4h is omitted.

  The reference rotation speed calculation unit 4j receives the target vehicle speed from the target vehicle speed calculation unit 3e, obtains a value obtained by converting the target vehicle speed into the rotation speed of the left and right drive wheels, and sets this value as the reference rotation speed.

  The left / right differential rotation speed calculation unit 4c uses the steering angle information from the steering angle sensor 1 so that the left / right differential rotation speed corresponds to the tire steering angle of the left and right front wheels, and the front wheel steering direction and front wheel steering. The left and right rear rotational speeds of the left rear wheel and the right rear wheel according to the corner are calculated (FIG. 3).

  The right target drive wheel rotational speed setting unit 4d sets the right target drive wheel rotational speed of the rear wheel to a value obtained by adding the right deviation rotational speed (± left-right differential rotational speed / 2) to the reference rotational speed.

  The right IWM current control unit 4i performs rotation speed feedback control so that the actual rotation speed of the right drive wheel of the rear wheel becomes the right target drive wheel rotation speed set by the right target drive wheel rotation speed setting section 4d. A three-phase AC current waveform is generated and applied to the right in-wheel motor 5. Since other configurations are the same as those of the first embodiment, illustration and description thereof are omitted.

Next, the operation will be described.
[Vehicle behavior stabilization when one wheel fails]
In the second embodiment, the value obtained by converting the target vehicle speed corresponding to the accelerator opening to the left and right drive wheel rotation speed (wheel speed) is set as the reference rotation speed, and the right target drive wheel rotation speed and the left target drive wheel rotation speed are the reference rotation speed. The target rotational speed difference between the left and right drive wheels is set so as to be the left / right differential rotational speed depending on the steering angle. Then, the rotational speed feedback control is performed in which the actual rotational speeds of the right driving wheel and the left driving wheel are matched with the right target driving wheel rotational speed and the left target driving wheel rotational speed, respectively.

  For example, when one wheel falls during driving and the wheel speed (= actual rotation speed) of the missing drive wheel decreases, the wheel on the drive wheel side that has failed with respect to the wheel speed on the normal drive wheel side Due to the decrease in speed, the wheel speed deviation width, which is the difference between the left and right driving wheel speeds, is increased, resulting in disturbance of vehicle behavior.

  On the other hand, when one of the wheels is lost during traveling and the driver performs an accelerator return operation or an accelerator release operation, the reference rotational speed decreases. When this reference rotational speed decreases, the target rotational speed of normal drive wheels decreases as the reference rotational speed decreases, and the rotational speed feedback control is performed to match the actual rotational speed with the target rotational speed. The actual rotational speed on the drive wheel side decreases as the target rotational speed decreases. For this reason, the wheel speed on the normal drive wheel side also decreases along with the decrease in the wheel speed on the failed drive wheel side, and the increase in the wheel speed deviation width is suppressed. As a result, when one wheel fails during traveling, the disturbance of the vehicle behavior can be suppressed, and the stabilization of the vehicle behavior is achieved.

[Effect of normal driver request]
In the first embodiment, the acceleration / deceleration torque that reflects the driver's acceleration / deceleration request is calculated. Therefore, the torque command value (for FB) based on the reference rotation speed is calculated separately, and the two torques are arbitrated by adding them together. ing.
On the other hand, in the second embodiment, the target vehicle speed corresponding to the accelerator opening is obtained, so that the target vehicle speed already reflects the driver's acceleration / deceleration request. Therefore, torque arbitration by torque calculation is unnecessary, the target drive wheel rotation speed based on the reference rotation speed is obtained, and the driver's intention to accelerate / decelerate can be achieved simply by performing control to obtain the target drive wheel rotation speed by the rotation speed feedback control. Acceleration / deceleration torque control that is directly realized is performed. That is, when the target drive wheel rotation speed> the actual rotation speed, the control is performed to increase the torque against the drive system load so that the actual rotation speed increases to the target drive wheel rotation speed. On the other hand, when the target drive wheel rotational speed is smaller than the actual rotational speed, the control is performed to reduce the torque so that the actual rotational speed is reduced to the target drive wheel rotational speed. Since other operations are the same as those of the first embodiment, description thereof is omitted.

Next, the effect will be described.
In the vehicle motion control device A2 of the second embodiment, the following effects can be obtained.

(6) In the vehicle motion control device A2 provided with drive control means (drive control controller 3) for independently controlling the torque of the left and right drive wheels of at least one of the front and rear wheels,
Driving wheel rotational speed control means (right motor controller & inverter 4, left motor controller & inverter) that performs rotational speed feedback control to match the actual rotational speed of each of the left and right driving wheels with the respective target driving wheel rotational speed of the left and right driving wheels 6)
Drive wheel rotation speed control means (right motor controller & inverter 4, left motor controller & inverter 6) calculates a value obtained by converting the target vehicle speed corresponding to the accelerator opening to the rotation speed of the left and right drive wheels, and uses this value as a reference Reference rotation speed calculation units 4j and 6j set to the rotation speed;
Using the steering angle so that the left / right differential rotation speed corresponds to the tire turning angle, the right deviation rotation speed, which is the rotation speed difference of the right drive wheel with respect to the reference rotation speed, and the rotation speed difference of the left drive wheel with respect to the reference rotation speed Left and right differential rotation speed calculation units 4c and 6c for calculating the left deviation rotation speed,
A target drive wheel speed setting unit 4d for setting the right target drive wheel speed by adding the right deviation speed to the reference speed and setting the left target drive wheel speed by adding the left deviation speed to the reference speed; 6d (FIG. 15).
For this reason, when one wheel falls during driving | running | working, disorder of a vehicle behavior can be suppressed. In addition, it is possible to perform acceleration / deceleration torque control that does not require torque calculation and directly realizes the driver's intention of acceleration / deceleration.

  As mentioned above, although the vehicle motion control apparatus of this invention has been demonstrated based on Example 1 and Example 2, it is not restricted to these Examples about a concrete structure, Each claim of a claim Design changes and additions are permitted without departing from the spirit of the invention.

  In the first and second embodiments, the front / rear deviation rotational speed limiting unit 4e is configured to change the front / rear deviation based on the same driven wheel speed on the right side so that the slip ratio of the right drive wheel that can be generated by the tire transmission torque does not exceed the allowable slip ratio. An example of determining the rotational speed limit value was shown. However, the front / rear deviation rotational speed limiter sets the front / rear deviation rotational speed limit value based on the same driven wheel speed on the right side so that the slip amount of the right drive wheel that can be generated by the tire transmission torque does not exceed the allowable slip amount. It may be decided.

  In the first and second embodiments, the vehicle motion control devices A1 and A2 are configured such that the left and right front wheels are driven wheels, the left and right rear wheels are in-wheel motor drive wheels, and the torques of the left and right rear wheels that are drive wheels are independently controlled. An example of application to a wheel drive-based in-wheel motor electric vehicle was shown. However, it is needless to say that the vehicle motion control device of the present invention can be applied to a front wheel drive-based in-wheel motor electric vehicle and a four-wheel drive in-wheel motor electric vehicle. And it is applicable not only to an in-wheel motor electric vehicle but also to a vehicle equipped with a drive system capable of controlling the torque (braking / driving force) of the left and right drive wheels.

A1, A2 Vehicle motion control device 1 Rudder angle sensor 2 Each sensor 3 Drive control controller (drive control means)
3a Acceleration / Deceleration Torque Calculation Unit 3b Parts Protection Torque Limiting Unit 3c Select Low Unit 3d Torque Limit Value Calculation Unit 3e Target Vehicle Speed Calculation Unit 4 Right Motor Controller & Inverter (Drive Wheel Speed Control Unit)
4a Left and right IWM rotation speed detection section 4b Reference rotation speed calculation section 4c Left and right differential rotation speed calculation section (left and right differential rotation speed calculation means)
4d Right target drive wheel rotational speed setting unit 4e Front / rear deviation rotational speed limiting unit 4f FB torque calculating unit 4g Target torque calculating unit 4h Torque limiting unit 4i Right IWM current control unit 4j Reference rotational speed calculating unit 5 Right in-wheel motor 6 Left motor Controller & inverter (drive wheel speed control means)
6a Left and right IWM rotation speed detection section 6b Reference rotation speed calculation section 6c Left and right differential rotation speed calculation section (left and right differential rotation speed calculation means)
6d Right target drive wheel rotational speed setting unit 6e Front / rear deviation rotational speed limiting unit 6f FB torque calculating unit 6g Target torque calculating unit 6h Torque limiting unit 6i Right IWM current control unit 6j Reference rotational speed calculating unit 7 Left in-wheel motor 8 VDC controller

Claims (6)

In the vehicle motion control device provided with drive control means for independently controlling the torque of the left and right drive wheels of at least one of the front and rear wheels,
Drive wheel rotation speed control means for performing rotation speed feedback control for matching the actual rotation speed of each of the left and right drive wheels with the target drive wheel rotation speed of each of the left and right drive wheels,
The drive wheel rotation speed control means includes a reference rotation speed calculation unit that calculates a reference rotation speed by taking an average value of the actual rotation speeds of the left and right drive wheels,
Using the steering angle so as to obtain a left / right differential rotational speed according to the tire turning angle, the right deviation rotational speed, which is the rotational speed difference of the right driving wheel with respect to the reference rotational speed, and the rotation of the left driving wheel with respect to the reference rotational speed A left / right difference rotation speed calculation unit for calculating a left deviation rotation speed that is a number difference;
The target drive wheel speed is set by adding the right deviation rotation speed to the reference rotation speed to set the right target drive wheel rotation speed, and adding the left deviation rotation speed to the reference rotation speed to set the left target drive wheel rotation speed. A vehicle motion control device comprising: a setting unit; The vehicle motion control device according to claim 1,
The drive wheel rotational speed control means determines the front / rear deviation rotational speed limit value based on the driven wheel speed on the same side of the left and right so that the slip of the left and right drive wheels that can be generated by the tire transmission torque does not exceed the allowable slip, A vehicle motion control device comprising: a front / rear deviation rotational speed limiter configured to limit each of the right target drive wheel rotational speed and the left target drive wheel rotational speed by the front / rear deviation rotational speed limit value. In the vehicle motion control device according to claim 2,
The front / rear deviation rotational speed limit unit calculates an allowable slip value for generating a tire lateral force required for cornering and sets the front / rear deviation rotational speed limit value to a value that increases or decreases according to the allowable slip value. A vehicle motion control device. In the vehicle motion control device according to any one of claims 1 to 3,
The drive wheel rotational speed control means is configured to control the right torque command value and the left torque by feedback control having a differential term based on a differential gain and a differential differential value based on a deviation between the target drive wheel rotational speed and the actual rotational speed of the left and right drive wheels. It has an FB torque calculation unit that calculates the command value,
The vehicle motion control apparatus, wherein the FB torque calculation unit adjusts the differential gain of the differential term to be a larger value as the steering speed is higher. In the vehicle motion control device according to any one of claims 1 to 4,
The drive control means includes a component protection torque limiter that calculates a torque limit value that protects each component constituting the drive / regeneration control system,
A select low part for selecting the strictest limit value among the torque limit values of the respective parts,
A torque limit value calculation unit having the selected limit value as a final torque limit value,
The drive wheel rotational speed control means includes a torque limiting unit that limits the right total torque command value and the left total torque command value from the target torque calculation unit by the final torque limit value. Motion control device. In the vehicle motion control device provided with drive control means for independently controlling the torque of the left and right drive wheels of at least one of the front and rear wheels,
Drive wheel rotation speed control means for performing rotation speed feedback control for matching the actual rotation speed of each of the left and right drive wheels with the target drive wheel rotation speed of each of the left and right drive wheels,
The drive wheel rotational speed control means obtains a value obtained by converting a target vehicle speed corresponding to the accelerator opening to the rotational speed of the left and right drive wheels, and sets this value as a reference rotational speed;
Using the steering angle so as to obtain a left / right differential rotational speed corresponding to the steering angle, the right deviation rotational speed that is the rotational speed difference of the right driving wheel with respect to the reference rotational speed and the rotational speed difference of the left driving wheel with respect to the reference rotational speed A left-right difference rotation speed calculation unit for calculating the left deviation rotation speed,
The target drive wheel speed is set by adding the right deviation rotation speed to the reference rotation speed to set the right target drive wheel rotation speed, and adding the left deviation rotation speed to the reference rotation speed to set the left target drive wheel rotation speed. A vehicle motion control device comprising: a setting unit;