JP2010208366A - Vehicle drive control system - Google Patents

Abstract

An object of the present invention is to provide a vehicle motion control system capable of preventing interference in stabilization control of turning motion at a low cost.
A vehicle motion control system changes a direction of a front wheel that is a steered wheel of a vehicle and a left and right driving force distribution device that generates a yaw moment by distributing different driving forces to left and right front wheels that are drive wheels. And a rear wheel toe angle control device that changes the toe angle of the rear wheel according to the operation angle θ _H of the steering handle. The left / right driving force distribution device has a left / right driving force distribution control ECU 37, and has a feed forward unit 71, a feedback control unit 73, and a driving force distribution amount control state monitoring unit 75. When the driving force distribution amount control state monitoring unit 75 is operating in a direction to increase the yaw rate in the turning direction of the vehicle, the second correction unit 67 in the rear wheel toe angle control ECU 36 operates the steering handle operating angle θ _H. The toe angle of the rear wheel is not controlled in the opposite phase to the direction of the.
[Selection] Figure 2

Description

  The present invention relates to a vehicle motion control system, and in particular, a left and right driving force distribution device that controls the distribution of driving force to left and right driving wheels to stabilize the vehicle, and a rear wheel that can change the toe angle of left and right rear wheels. The present invention relates to a vehicle motion control system including a steering device.

  In a driving force distribution device that distributes driving force to the left and right wheels to control the yaw moment of the vehicle, feedback control of the driving force distribution amount based on engine speed, vehicle speed, steering wheel operating angle, lateral acceleration, yaw rate, etc. However, it is disclosed in Patent Document 1 and the like.

Patent Document 2 includes a left / right driving force distribution device that distributes driving force to the left and right rear wheels to control the yaw rate of the vehicle, and a rear wheel steering device that can change the toe angle of the left and right rear wheels. The control ratio of the left / right driving force distribution device is increased as the throttle opening of the engine is larger, and is decreased as the vehicle speed increases, and the control ratio of the rear wheel steering device is decreased as the throttle opening of the engine is larger. In addition, a technique for increasing the vehicle speed as the vehicle speed increases is disclosed.
In the technique of Patent Document 2, when the driving force on the ground contact surface of the rear wheel, which is the driving wheel, is increased, the cornering force of the rear wheel cannot be increased. When the driving force on the ground contact surface of the rear wheel, which is the driving wheel, is small, the cornering force of the rear wheel can be increased. In this case, it is allowed to increase the rear wheel toe angle.

Japanese Patent Laid-Open No. 9-309357 (see FIG. 6) Japanese Patent No. 3357114 (see FIG. 6)

  However, when the driving wheel is a front wheel, the rear wheel is a driven wheel, and therefore, it is necessary to properly control the control ratio of the left and right driving force distribution device and the control ratio of the rear wheel steering device as in Patent Document 2. There is no.

  In addition, the left and right driving force distribution control program used for the control function unit of the left and right driving force distribution device and the rear wheel toe angle control program used for the control function unit of the rear wheel steering device are separately provided by manufacturers specializing in each. It is usually developed to. The left and right driving force distribution device and the rear wheel steering device each have a control ECU (Electric Control Unit) composed of a microcomputer including a CPU, ROM, RAM, etc., and its input / output interface circuit, etc. The left and right driving force distribution control program and the rear wheel toe angle control program are stored in the ROM of the control ECU. The control ECUs are connected to each other via a communication line, and necessary control data is exchanged via the communication line. I often do it.

  In the vehicle motion control system including the left / right driving force distribution device and the rear wheel steering device configured as described above, the control is performed in a coordinated manner so as not to interfere with each other in the turning motion stabilization control by the left / right driving force distribution control and the rear wheel toe angle control. Measures are needed. One solution is a method of creating an integrated program in which the left / right driving force distribution control program and the rear wheel toe angle control program are integrated, and mounting the integrated program in one control ECU. However, in this countermeasure, for example, one model is equipped with both the A model equipped with the left and right driving force distribution device, the B model equipped with the rear wheel steering device, both the left and right driving force distribution device and the rear wheel steering device. When producing the C model, it is necessary to develop three types of the left and right driving force distribution control program, the rear wheel toe angle control program, and the integrated program among the three types of A, B, and C models. Development of the control program is a double investment, which increases production costs.

  The present invention has been made in view of the above circumstances, and a vehicle motion control system capable of preventing interference in the stabilization control of turning motion for a vehicle including a left / right driving force distribution device and a rear wheel steering device at a low cost. The purpose is to provide.

  In order to solve the above-mentioned problem, a vehicle motion control system according to claim 1 is a left-right driving force distribution device that generates a yaw moment by distributing different driving forces to left and right driving wheels of a vehicle; A vehicle motion control system comprising at least a rear wheel toe angle control device that changes a toe angle of a rear wheel in accordance with an operation angle of a steering handle that changes the direction of a front wheel that is a steered wheel of a vehicle, The rear wheel toe angle control device does not control the rear wheel toe angle in a phase opposite to the direction of the steered wheel when the force distribution device is operated in a direction to increase the yaw rate in the turning direction of the vehicle. To do.

  For example, in a technology in which the control ECU of the left and right driving force distribution device and the control ECU of the rear wheel toe angle control device are individually combined and connected by a communication line to form a vehicle motion control system, the control ECU of the left and right driving force distribution device and Consider a case in which the control ECU of the rear wheel toe angle control device has a function of determining that the actual yaw rate is smaller on the turning side and the understeer state than the standard yaw rate. When the control ECU of the left / right driving force distribution device corrects the understeer state and performs yaw moment control to increase the yaw rate in the turning direction, the control ECU of the rear wheel toe angle control device also determines the direction of the steered wheels. If the toe angle control is reversed, the additional yaw moment amount of the rear wheel toe angle control device is added to the yaw moment control of the left / right driving force distribution device, resulting in an excessive yaw moment increase and stable turning. This will cause problems in the control.

  On the other hand, according to the first aspect of the invention, when the left / right driving force distribution device is operating in the direction of increasing the yaw rate, the rear wheel toe angle control device is in a phase opposite to the direction of the steered wheels. Since the toe angle of the rear wheel is not controlled, it is possible to prevent the yaw moment control direction by the left and right driving force distribution device and the yaw moment control direction by the rear wheel toe angle control device from overlapping, resulting in excessive yaw moment control. In addition, stabilization control of the turning motion of the vehicle can be performed.

  A vehicle motion control system according to a second aspect of the present invention includes, in addition to the configuration of the first aspect of the invention, vehicle running state information including at least the speed of the vehicle, the operating angle of the steering wheel, and the actual yaw rate of the vehicle. Vehicle running state information acquisition means for acquiring the reference yaw rate for calculating the reference yaw rate based on at least the speed of the vehicle and the operating angle of the steering handle among the vehicle running state information acquired by the vehicle running state information acquisition means And a yaw rate deviation calculating means for acquiring a deviation between the reference yaw rate calculated by the reference yaw rate calculating means and the acquired actual yaw rate, and the rear wheel toe angle control device is acquired by the yaw rate deviation calculating means. When the deviation is equal to or greater than a predetermined threshold, it is also possible to control the toe angle of the rear wheel in the opposite phase to the direction of the steered wheel. To.

  According to the second aspect of the present invention, the rear wheel toe angle control device, when the deviation acquired by the yaw rate deviation calculating means is equal to or greater than a predetermined threshold value, Control of the angle is also allowed, so when the driving force against the ground contact surface of the front wheel is saturated in the understeer state and the yaw moment amount by the left and right driving force distribution device is insufficient, it is controlled by reverse phase control of the toe angle of the rear wheel. Can be compensated for and a stable turning motion can be achieved.

  A vehicle motion control system according to a third aspect of the present invention includes, in addition to the configuration of the first aspect of the present invention, a vehicle running state including at least a vehicle speed, an operation angle of the steering handle, and an actual yaw rate of the vehicle. Vehicle driving state information acquisition means for acquiring information, left and right driving force distribution control state acquisition means for acquiring left and right driving force distribution control state of the left and right driving force distribution device, and vehicle driving state acquired by the vehicle driving state information acquisition means The target toe angle setting means for setting the target toe angle of the rear wheel based on at least the vehicle speed and the steering wheel operation angle in the information, and the left and right driving force distribution control state from the left and right driving force distribution control state acquisition means And a target toe angle correction unit that corrects the set target toe angle based on the left and right driving force distribution control information, and is acquired by the left and right driving force distribution control state acquisition unit. When the left / right driving force distribution control information indicates that the left / right driving force distribution device is operating in a direction to increase the yaw rate in the turning direction of the vehicle, the target toe angle correction means sets the target toe angle setting. When the target toe angle output from the means is in a phase opposite to the direction of the steered wheels, the toe angle of the rear wheels is set to almost zero.

  According to the third aspect of the present invention, when the left / right driving force distribution device is operating in the direction of increasing the yaw rate, the rear wheel toe angle control device is configured so that the rear wheel toe angle control device is in a phase opposite to the direction of the steered wheel. Since the angle is not controlled, the direction of the yaw moment control by the left / right driving force distribution device and the direction of the yaw moment control by the rear wheel toe angle control device can be prevented from overlapping, and excessive yaw moment control can be prevented. The stabilization of movement can be controlled.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the present invention, the vehicle motion control system further includes at least the speed of the vehicle in the vehicle travel state information acquired by the vehicle travel state information acquisition means. Based on the operating angle of the steering handle, a normative yaw rate calculating means for calculating a normative yaw rate, a normative yaw rate calculated by the normative yaw rate calculating means, and a yaw rate deviation calculating means for acquiring a deviation between the acquired actual yaw rate, And the target toe angle correcting means permits to control the toe angle of the rear wheel in a phase opposite to the direction of the steered wheel when the deviation acquired by the yaw rate deviation calculating means is equal to or greater than a predetermined threshold value. Features.

  According to the fourth aspect of the present invention, the rear wheel toe angle control device, when the deviation acquired by the yaw rate deviation calculating means is equal to or greater than a predetermined threshold value, Since the control of the angle is also allowed, when the driving force against the ground contact surface of the front wheel is saturated in the understeer state and the yaw moment amount by the left and right driving force distribution device is insufficient, this is caused by the reverse phase of the toe angle of the rear wheel. It is possible to make up a stable turning motion.

  According to the present invention, a control ECU is provided in each of the left and right driving force distribution device and the rear wheel toe angle control device as in the prior art, and in each of the left and right driving force distribution device and the rear wheel toe angle control device, for example, the reference yaw rate is set. Even if it is based on a program that calculates and controls the yaw moment so that the actual yaw rate matches the standard yaw rate, for example, the left and right driving force distribution is acquired by the control ECU of the left and right driving force distribution device The control state acquisition means is provided, and the acquired left / right driving force distribution control state is output to the target toe angle correction means provided in the control ECU of the rear wheel toe angle control device, and the target toe angle is controlled according to the left / right driving force distribution control state. Since the angle is corrected, it is additionally supported by a control program developed independently for each control ECU of the conventional left / right driving force distribution device and the rear wheel toe angle control device. By adding a routine program, it can be configured vehicle motion control system the rear wheel toe angle control device cooperative control to the left and right driving force distribution device at low cost.

FIG. 1 is a skeleton diagram of a power transmission system of a vehicle to which a vehicle motion control system according to an embodiment of the present invention is applied, and an electric power steering control ECU, a left / right driving force distribution control ECU constituting the vehicle motion control system, It is the figure which combined the block diagram of wheel toe angle control ECU and brake control ECU. It is a block diagram for demonstrating the control logic in the vehicle motion control system. It is a block diagram which shows the function structure of right-and-left driving force distribution control ECU. It is a flowchart which shows the flow of correction | amendment control of the target toe angle in the 2nd correction | amendment part of rear-wheel toe angle control ECU. It is a flowchart which shows the flow of correction | amendment control of the target toe angle in the 2nd correction | amendment part of rear-wheel toe angle control ECU.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a skeleton diagram of a power transmission system of a vehicle to which a vehicle motion control system according to an embodiment of the present invention is applied, and an electric power steering control ECU, a left / right driving force distribution control ECU constituting the vehicle motion control system, It is the figure which combined the block diagram of wheel toe angle control ECU and brake control ECU.
FIG. 2 is a block diagram for explaining the control logic in the vehicle motion control system.

As shown in FIG. 1, the vehicle is a front wheel drive vehicle, and includes a driving force transmission device T and a front wheel steering device 21. This vehicle is an electric power steering control ECU (Electric Control Unit) 35 (hereinafter referred to as “EPS (Electric Power Steering) control ECU 35”), which is a control unit of the front wheel steering device 21, as a vehicle motion control system. After target output to rear wheel toe angle change control ECUs 42L and 42R, which are control units of rear wheel toe angle changing devices 41L and 41R that change toe angles of wheels W _RL and W _RR , and rear wheel toe angle change control ECUs 42L and 42R Rear wheel toe angle control ECU 36 that calculates the wheel toe angle, left and right driving force distribution control ECU 37 that performs left and right driving force distribution control to the front wheels W _FL and W _FR by the driving force transmission device T via the hydraulic circuit 28, and various other types Sensors, for example, wheel speed sensors 30 _FL , 30 _FR , 30 _RL , 30 for detecting the wheel speeds of the left and right front wheels W _FL , W _FR and the left and right rear wheels W _RL , W _{RR. RR} , yaw rate sensor (vehicle running state information obtaining means) 31 for detecting actual yaw rate (vehicle running state information) γ, lateral acceleration sensor (vehicle running state information obtaining means) for detecting lateral acceleration (vehicle running state information) α _Y 32, a steering wheel operating angle sensor (vehicle driving state information acquisition means) 33 for detecting an operating angle (vehicle driving state information) θ _H of the steering handle 21a is provided.
If it is not necessary to distinguish the left and right front wheels W _FL , W _FR and the left and right rear wheels W _RL , W _RR from the front wheels and the rear wheels, the wheels W _FL , W _FR , W _RL , W _RR or It is simply referred to as wheel W. Further, the operation angle θ _H of the steering handle 21a is simply referred to as “handle operation angle θ _H ”.

The left / right driving force distribution control ECU 37 controls the driving force transmission device T via the hydraulic circuit 28 for motion control during turning of the vehicle, and each wheel W _FL , W for motion control during turning. The brakes B _FL , B _FR , B _RL , B _RR of _{FR 1} , W _RL , W _RR are controlled via the brake control ECU 29.

Incidentally, the vehicle is also provided with an engine control ECU 27 for controlling the engine ENG, and acquires an engine rotational speed Ne (see FIG. 3) based on a signal from a crank pulse sensor (not shown) of the engine ENG, The engine torque T _ENG (see FIG. 3) output from the engine ENG is estimated from a speed Ne, a signal from an accelerator opening sensor (not shown), a fuel injection amount, and the like.
The engine control ECU 27, the brake control ECU 29, the EPS control ECU 35, the rear wheel toe angle control ECU 36, the left and right driving force distribution control ECU 37, and the rear wheel toe angle change control ECUs 42L and 42R are all CPU (Central Processing Unit), ROM (Read Only). A microcomputer including a memory (RAM), a random access memory (RAM), an input / output interface circuit, and a drive power supply circuit required for each ECU. Each of the ECUs communicates with each other by, for example, CAN (Control Area Network) communication, and can input and output necessary control data.
And each above-mentioned ECU has a non-volatile memory and a volatile memory as needed.

(Power transmission system)
First, a vehicle power transmission system to which the vehicle motion control system of this embodiment is applied will be described. A transmission T / M is connected to the right end of an engine ENG mounted horizontally at the front of the vehicle body, and a driving force transmission device T is disposed at the rear of the engine ENG and the transmission T / M. The left drive shaft A _L and the right drive shaft A _R extending left and from the right to the left and right driving force transmitting device T, the left front wheel W _FL and the right front wheel W _FR are each driven wheel is connected.

The driving force transmission device T includes a differential D to which a driving force is transmitted from an external gear 3 that meshes with an input gear 2 provided on an input shaft 1 extending from the transmission T / M. The differential D comprises a double pinion planetary gear mechanism, and meshes with the ring gear 4, a ring gear 4 formed integrally with the external gear 3, a sun gear 5 disposed coaxially within the ring gear 4, and the ring gear 4. The outer planetary gear 6 and the inner planetary gear 7 that meshes with the sun gear 5 are constituted by a planetary carrier 8 that supports the outer planetary gear 6 and the sun planetary gear 5 in a state where they mesh with each other. The differential D has its ring gear 4 functions as an input element, a sun gear 5 which functions as one output element is connected to the left drive shaft A _L via a half shaft 9, also functions as the other output element planetary carrier 8 is connected to the right drive shaft a _R.

  The carrier member 11 rotatably supported on the outer periphery of the half shaft 9 includes four pinion shafts 12 arranged at intervals of 90 ° in the circumferential direction. The first pinion 13, the second pinion 14, A triple pinion member 16 in which the three pinions 15 are integrally formed is rotatably supported by each pinion shaft 12. Although the number of triple pinion members 16 is four in the present embodiment, the number is not limited to four and may be two or more.

  A first sun gear 17 that is rotatably supported on the outer periphery of the half shaft 9 and meshes with the first pinion 13 is connected to the planetary carrier 8 of the differential D. The second sun gear 18 fixed to the outer periphery of the half shaft 9 meshes with the second pinion 14. Further, the third sun gear 19 rotatably supported on the outer periphery of the half shaft 9 meshes with the third pinion 15.

The third sun gear 19 can be connected to the casing 20 via a left hydraulic clutch C _L, the rotational speed of the carrier member 11 is increased by the engagement of the left hydraulic clutch C _L. The carrier member 11 can be coupled to the casing 20 via a right hydraulic clutch C _R, the rotational speed of the carrier member 11 is reduced by the engagement of the right hydraulic clutch C _R.
Then, the left hydraulic clutch C _L and the right hydraulic clutch C _R is controlled via the hydraulic circuit 28 by the right and left driving force distribution control ECU 37.

  The structures of the differential D, the driving force transmission device T, and the hydraulic circuit 28 are those described in, for example, paragraphs [0016] to [0031] and FIGS. 2 to 5 of Japanese Patent Laid-Open No. 9-309357. Detailed description is omitted.

Next, the operation of the driving force transmission device T will be described.
When the vehicle travels straight, both the left hydraulic clutch _CL and the right hydraulic clutch _CR are disengaged. Thereby, the restraint of the carrier member 11 and the third sun gear 19 is released, and the planetary carrier 8 and the carrier member 11 of the half shaft 9, the left drive shaft A _L , the right drive shaft A _R , and the differential D are all rotated together. To do. At this time, the torque of the engine ENG is evenly transmitted from the differential D to the left and right front wheels W _FL and W _FR .

Now, at the time of right turn of the vehicle, with the hydraulic circuit 28 is controlled to the left and right driving force distribution control ECU 37, the right hydraulic clutch C _R is engaged, bonded to stopping the carrier member 11 to the casing 20. At this time, the half shaft 9 and the left drive shaft A _L integral with the left front wheel W _FL and the right drive shaft A _R integral with the right front wheel W _FR (that is, the planetary carrier 8 of the differential D) are the second sun gear 18. Since the second pinion 14, the first pinion 13 and the first sun gear 17 are connected, the rotational speed N _L of the left front wheel W _FL is increased with respect to the rotational speed N _R of the right front wheel W _FR. .

When the rotation speed N _L of the left front wheel W _FL is increased with respect to the rotation speed N _R of the right front wheel W _FR, a turning inner front right wheel W _FR are part of the turning outer is left front wheel W _FL torque Can be communicated to.
Instead of stopping the carrier member 11 by the right hydraulic clutch C _R, when decelerating the rotational speed of the carrier member 11 by appropriately adjusting the engagement force of the right hydraulic clutch C _R, the left front wheel W _FL in accordance with the deceleration can be of increasing the rotational speed N _L with respect to the rotational speed N _R of the right front wheel W _FR Hayashi, to transmit any torque from the right front wheel W _FR as a turning-inner to the left front wheel W _FL is the outer turning wheel.

On the other hand, when the vehicle turns left, the hydraulic circuit 28 is controlled by the left / right driving force distribution control ECU 37, the left hydraulic clutch _CL is engaged, and the third pinion 15 is coupled to the casing 20 via the third sun gear 19. The As a result, the rotation speed of the carrier member 11 is increased with respect to the rotation speed of the half shaft 9, and the rotation speed N _R of the right front wheel W _FR is increased with respect to the rotation speed N _L of the left front wheel W _FL .

When the rotational speed N _R of the right front wheel W _FR is increased with respect to the rotation speed N _L of the left front wheel W _FL, a part of the torque of the left front wheel W _FL as a turning-inner is the outer turning wheel right front wheel W _FR Can be communicated to. In this case, when increasing the rotational speed of the carrier member 11 by appropriately adjusting the engagement force of the left hydraulic clutch C _L, the right front wheel W _FR rotational speed N _R of the left front wheel W _FL in response to the speed increasing can Hayashi increased with respect to the rotation speed N _L, to transmit any torque from the left front wheel W _FL as a turning-inner front right wheel W _FR is the outer turning wheel.

  The driving force transmission device T, the hydraulic circuit 28, and the left / right driving force distribution control ECU 37 in the present embodiment constitute the “left / right driving force distribution device” of the present invention.

(Front wheel steering device)
Next, the configuration of the front wheel steering device 21 in the present embodiment will be described.
The front wheel steering device 21 is a rack and pinion type electric power steering device, and is a steering wheel 21a operated by a driver, a handle shaft 21b, and a worm wheel provided on a pinion shaft 21d connected to the handle shaft 21b. For electric power steering, which is directly connected to the gear 23 and the worm gear 24b meshing with the worm wheel gear 23 to give a steering assist force for reducing the manual steering force by the steering handle 21a and a steering resistance force to the steering handle 21a. A motor (hereinafter referred to as “EPS motor”) 24, a pinion gear 21e provided on the lower end side of the pinion shaft 21d, a rack shaft 22c including rack teeth 22a meshing with the pinion gear 21e, and the like are configured. . As the EPS motor 24, for example, a brushless DC motor is used.
Then, the rotation of the pinion shaft 21d due to the rotation operation of the steering handle 21a is converted into a linear motion of the rack shaft 22c, and the front wheels W _FL and W _FR which are steered wheels are steered via the tie rods 22d and 22d. .

Further, the front wheel steering device 21, EPS control ECU35 for controlling the EPS motor 24 via the motor driving circuit 26, a steering torque sensor 25 that detects the steering torque T _rq applied to the pinion shaft 21d, the operation angle of the steering wheel 21a It includes a steering wheel operation angle sensor 33 that detects θ _H , a motor rotation angle sensor 34 that detects the motor rotation angle θ _M of the EPS motor 24, a differential amplification circuit (not shown) that amplifies the output of the steering torque sensor 25, and the like. Has been. Signals from the differential amplifier circuit, the handle operation angle sensor 33, and the motor rotation angle sensor 34 are input to the EPS control ECU 35.

The motor drive circuit 26 includes a plurality of switching elements such as an H-type bridge circuit, for example, and generates a rectangular wave current using a DUTY signal from the EPS control unit 55 of the EPS control ECU 35 as shown in FIG. , A power supply circuit for driving the EPS motor 24. The motor drive circuit 26 has a function of detecting a motor current using a motor current sensor (not shown) and a function of detecting a motor voltage using a motor voltage sensor (not shown). Incidentally, in the present embodiment, the signal of the steering wheel operation angle θ _M is input to the EPS control unit 55 of the EPS control ECU 35, but is not used in the EPS control unit 55, but via the communication line 49 (see FIG. 1). For example, it is input to the rear wheel toe angle control ECU 36 and the left / right driving force distribution control ECU 37.

(EPS control unit)
The EPS control unit 55 has a known configuration and is omitted in FIG. 2. For example, two-dimensional map data of the vehicle speed (vehicle speed) VS and the steering torque _Trq is stored in the ROM in advance. The base target current value corresponding to the steering assist force is calculated based on the two-dimensional map data with reference to the VS and the steering torque _Trq, and the base current calculation unit that outputs the base target current value to the motor drive circuit 26. Inertia compensator for correcting the start-up characteristic, damper compensator for calculating the motor rotation angular velocity from the motor rotation angle θ _M of the EPS motor 24, and adjusting the steering assist force from the turning angular velocity of the front wheels W _FL and W _FR , etc. The inertia compensator and the damper compensator output a correction current value for correcting the base target current value, and output the corrected target current value to the motor drive circuit 26.
The EPS control unit 55 includes a deviation unit that detects an actual current value or voltage value from the motor drive circuit 26 and calculates a difference from the corrected target current value. Performs feedback control according to the deviation with respect to the corrected target current value.

(Brake control device)
Next, returning to FIG. 1, the brake pedal and master cylinder (not shown), and the brakes B _FL , B _FR , B _RL , B _RR , hydraulic circuit 46 of each wheel W _FL , W _FR , W _RL , W _RR A brake control device constituted by a brake control ECU 29 that controls the hydraulic circuit 46 will be described.
Each wheel W _FL , W _FR , W _RL , W _RR is provided with a wheel speed sensor 30 _FL , 30 _FR , 30 _RL , 30 _RR , and the wheel speed VW _FR , VW _FL , VW _RL , VW _RR is set. Detected and input to the brake control ECU 29.
The brake control ECU 29 includes a vehicle speed calculation unit (vehicle traveling state information acquisition unit) 51 and an ABS (Anti-lock Brake System) control unit 53. The vehicle speed calculation unit 51 calculates a vehicle speed (vehicle traveling state information) VS that is a vehicle speed from the input wheel speeds VW _FR , VW _FL , VW _RL , VW _RR , and controls the engine via the communication line 49. The vehicle speed VS is input to the ECU 27, EPS control ECU 35, rear wheel toe angle control ECU 36, and left / right driving force distribution control ECU 37.
The ABS control unit 53 has a conventionally known ABS function, calculates the slip rate of each wheel W from the vehicle speed VS and each wheel speed VW during braking, and prevents each wheel W from locking. The brake fluid pressures of the wheel cylinders (not shown) of the brakes B _FL , B _FR , B _RL , B _RR are adjusted via a fluid pressure circuit 46. Further, the ABS control unit 53 calculates slip ratios of the front wheels W _FL and W _FR that are drive wheels during acceleration and the like, and performs control to prevent the front wheels W _FL and W _FR from slipping.

(Rear wheel toe angle control ECU and rear wheel toe angle changing device)
Next, the configuration of the rear wheel toe angle control ECU 36 and the rear wheel toe angle changing devices 41L and 41R in the present embodiment will be described with reference to FIGS.
As shown in FIG. 1, rear wheel toe angle changing devices 41L and 41R are provided on the rear wheels W _RL and W _RR , respectively. The rear wheel toe angle changing device 41L includes a rear wheel toe angle changing control ECU 42L, an actuator 43L, and a rear wheel toe angle sensor 44L. Similarly, the rear wheel toe angle changing device 41R includes a rear wheel toe angle changing control ECU 42R, an actuator 43R, and a rear wheel toe angle sensor 44R.

Although not shown, for example, in the case of a trailing arm type rear suspension device, the front end of the trailing arm extending substantially in the vehicle longitudinal direction is supported near the vehicle width direction end of the cross member of the vehicle body. A rear wheel W _RL (W _RR ) is fixed to the rear end of the trailing arm. In the trailing arm, a vehicle body side arm attached to the cross member and a wheel side arm fixed to the rear wheel W _RL (W _RR ) are connected via a substantially vertical rotation shaft. As a result, the trailing arm can be displaced in the vehicle width direction.

One end of the actuator 43L (43R) is attached to the front end portion of the wheel side arm in front of the rotation shaft via a ball joint, and the other end is attached to the cross member of the vehicle body via the ball joint.
For example, the actuator 43L (43R) is configured to include an electric motor, a speed reduction mechanism, a feed screw portion, and the like, and the feed screw portion expands and contracts by rotation of the electric motor in the forward and reverse directions, so that the trailing arm extends in the vehicle width direction. Displace.

Rear wheel toe angle change control ECU42L, in response to the signal of the target toe angle theta _TRT outputted from the rear wheel toe angle control ECU 36 _(L2), or feedforward control the toe angle of the left rear wheel W _RL, rear wheel Feedback control is performed in accordance with the deviation between the actual toe angle θ _{RT (L)} signal from the toe angle sensor 44L and the target toe angle θ _{TRT (L2)} .
Rear wheel toe angle change control ECU42R, in response to the signal of the target toe angle theta _TRT outputted from the rear wheel toe angle control ECU 36 _(R2), or a feed forward control the toe angle of the right rear wheel W _RR, rear wheel Feedback control is performed according to the deviation between the actual toe angle θ _{RT (R)} signal from the toe angle sensor 44R and the target toe angle θ _{TRT (R2)} .
Here, the rear wheel toe angle control ECU 36 and the rear wheel toe angle change control ECUs 42L and 42R constitute a “rear wheel toe angle control device” recited in the claims.

As shown in FIG. 2, the rear wheel toe angle control ECU 36 includes a steering wheel operation angle differentiating unit 61, a target toe angle calculating unit 62, a reference yaw rate calculating unit 63, a subtracting unit 64, a feedback correction amount calculating unit 65, and a first function unit. The correction unit 66, the second correction unit 67, and the phase lag compensation unit 68 are included.
Here, the target toe angle calculation unit 62 and the first correction unit 66 constitute “target toe angle setting means” described in the claims, and the second correction unit 67 includes “target toe angle correction” described in the claims. Means ".

The steering wheel operation angle differentiation unit 61 calculates the steering wheel operation angular velocity θ ′ _H by differentiating the steering wheel operation angle θ _H with respect to time, and inputs it to the target toe angle calculation unit 62.
The target toe angle calculation unit 62 refers to the steering wheel operation angle θ _H , the vehicle speed VS, and the steering wheel operation angular velocity θ ′ _H , and sets the target of each of the left and right rear wheels W _RL and W _RR based on the target toe angle map data 62a. The toe angles θ _{TRT (L0)} and θ _{TRT (R0)} are calculated and output to the first correction unit 66.
The target toe angle map data 62a is, for example, three-dimensional map data of the steering angle θ _H , the absolute value of the steering angular velocity θ ′ _H , and the vehicle speed VS. Specifically, when the vehicle speed VS indicates a low speed, the rear wheels W _RL and W _RR are opposite in phase to the front wheels W _FL and W _FR that are steered wheels, and a toe angle corresponding to the steering angle θ _H is targeted. When the toe angles θ _{TRT (L0)} and θ _{TRT (R0)} are set and the vehicle speed VS is equal to or higher than the first predetermined vehicle speed value, the toe angle corresponding to the steering angle θ _H is set to the target toe angle θ _{TRT ( L0)} and θ _{TRT (R0)} are designed to attenuate the gain. When the vehicle speed VS is equal to or higher than a second predetermined vehicle speed value greater than the first predetermined vehicle speed, a toe angle corresponding to the steering angle θ _H is set in phase with the front wheels W _FL and W _FR to a target toe angle θ _{TRT (L0).} , Θ _{TRT (R0)} , the gain is often increased and gradually saturated with the vehicle speed VS.

However, the target toe angle map data 62a indicates that even when the vehicle speed VS is equal to or higher than the second predetermined vehicle speed value, a large angle where the absolute value of the steering wheel operation angle θ _H is equal to or higher than a predetermined value or the steering wheel operation angular velocity θ ′ _H When the absolute value is greater than or equal to the specified value, the data structure is such that the target toe angles θ _{TRT (L0)} and θ _{TRT (R0)} of the opposite phase corresponding to the steering angle θ _H are set, and the vehicle runs at high speed. In many cases, the danger avoidance exercises can be performed accurately.

The reference yaw rate calculation unit (reference yaw rate calculation means) 63 has three-dimensional map data 63a of the steering wheel operation angle θ _H , the lateral acceleration α _Y , and the vehicle speed VS stored in advance in the ROM, and the steering wheel operation angle θ _H , The reference yaw rate γ _TB is calculated based on the three-dimensional map data 63 a with reference to the lateral acceleration α _Y and the vehicle speed VS, and is input to the subtraction unit (yaw rate deviation calculation means) 64 and the second correction unit 67.
The subtraction unit 64 calculates a difference (deviation) Δγ _B (= γ _TB −γ) between the reference yaw rate γ _TB calculated by the reference yaw rate calculation unit 63 and the actual yaw rate γ, and the feedback correction amount calculation unit 65 and 2 is input to the correction unit 67.
The feedback correction amount calculation unit 65 calculates a target toe angle correction amount Δθ _TRT corresponding to the difference Δγ _{B based} on, for example, one-dimensional map data using a vehicle speed VS (not shown) as a reference parameter, and performs the first correction. Input to the unit 66.

The first correction unit 66 determines whether or not the target toe angles θ _{TRT (L0)} and θ _{TRT (R0)} input from the target toe angle calculating unit 62 are in reverse phase with respect to the steering wheel operation angle θ _H. When it is determined that the phase is opposite, the target toe angle correction amount Δθ _TRT is added to the target toe angles θ _{TRT (L0)} and θ _{TRT (R0)} to obtain target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} . Input to the second correction unit 67.
The second correction unit 67 outputs a driving force distribution amount control state monitoring unit (left / right driving force distribution control state acquisition unit) 75 to be described later with respect to the input target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} . Corrected as necessary based on left and right driving force distribution control information, normative yaw rate γ _TB , difference Δγ _B, etc., and then input to target phase angle θ _{TRT (L2)} , θ _{TRT (R2)} to phase delay compensation unit 68 To do.
Detailed functions of the second correction unit 67 will be described in the description of the flowcharts of FIGS. 4 and 5.

In FIG. 2, the phase lag compensation unit 68 is omitted from the arrow of the handle operation angular velocity θ ′ _H from the handle operation angle differentiating unit 61. For example, the absolute value of the handle operation angular velocity θ ′ _H is the first handle. It is zero until the operation angular velocity threshold, and when it exceeds the first steering operation angular velocity threshold, the gain increases smoothly, and gain correction is performed by a characteristic function that saturates to a constant value above the second steering operation angular velocity threshold. The characteristic function is appropriately set according to the response characteristics of the rear wheel toe angle changing devices 41L and 41R.

Incidentally, here, the target toe angles θ _{TRT (L0)} , θ _{TRT (R0)} , target toe angles θ _{TRT (L1)} , θ _{TRT (R1)} , target toe angles θ _{TRT (L2)} , θ _{TRT (R2)} The left and right angles are defined such that the toe angle to the left is a negative value and the toe angle to the right is a positive value, and the vehicle body front direction is defined as ± 0 °. Therefore, taking the target toe angles θ _{TRT (L0)} and θ _{TRT (R0)} as an example, when toe-in the rear wheel toe angle, the target toe angle θ _{TRT (L0)} is a positive value, and the target toe angle θ _{TRT (R0)} is a negative value. When toe-out control of the rear wheel toe angle is performed, the target toe angle θ _{TRT (L0)} is a negative value, and the target toe angle θ _{TRT (R0)} is a positive value.

(Left and right driving force distribution control ECU)
Next, a detailed functional configuration of the left / right driving force distribution control ECU 37 will be described with reference to FIG. 1 and FIG. 2 as appropriate with reference to FIG. FIG. 3 is a block diagram showing a functional configuration of the left / right driving force distribution control ECU.
As shown in FIG. 1, a signal indicating the actual yaw rate γ from the yaw rate sensor 31 and a signal indicating the lateral acceleration α _Y from the lateral acceleration sensor are input to the left / right driving force distribution control ECU 37, and are required via the communication line 49. It is also input to other ECUs.
As shown in FIG. 3, the left / right driving force distribution control ECU 37 includes a feedforward control unit 71 and a feedback control unit 73. In addition to the lateral acceleration α _Y , the vehicle speed VS and the steering wheel operation angle θ _H are input to the feedforward control unit 71 via the communication line 49, and the engine torque T _ENG and the engine rotation speed Ne are input to the engine control ECU 27 (FIG. 1) through the communication line 49. In addition to the lateral acceleration α _Y and the actual yaw rate, the vehicle speed VS and the steering wheel operation angle θ _H are input to the feedback control unit 73 via the communication line 49.

The feedforward control unit 71 includes a lateral acceleration determination unit 81, a lateral acceleration estimation unit 82, a turning amount calculation unit 83, a gear ratio determination unit 84, a driving force calculation unit 85, a driving force distribution amount calculation unit 86, and a driving force distribution amount conversion. In addition to the unit 87, the addition unit 88, and the left / right turning determination unit 89, the driving force distribution amount control state monitoring unit 75 is included.
The lateral acceleration determination unit 81 determines the lateral acceleration based on the lateral acceleration α _Y and outputs it to the turning amount calculation unit 83. The lateral acceleration estimation unit 82 determines the lateral acceleration based on the vehicle speed VS and the steering wheel operation angle θ _H. Is output to the turning amount calculation unit 83. The turning amount calculation unit 83 calculates the turning amount of the vehicle, that is, the yaw moment, based on these two types of lateral acceleration. Since the lateral acceleration estimated by the lateral acceleration estimating unit 82 rises faster than the lateral acceleration determined based on the signal of the lateral acceleration α _Y from the lateral acceleration sensor 32, the turning amount calculating unit 83 adds both. The turning amount, that is, the yaw moment is calculated by the averaged lateral acceleration and input to the driving force distribution amount calculating unit 86 and the left / right turning determining unit 89.

On the other hand, the gear ratio determination unit 84 determines a gear ratio including the transmission T / M (see FIG. 1) and the differential D based on the vehicle speed VS and the engine rotation speed Ne, and inputs the determined gear ratio to the driving force calculation unit 85. The driving force calculation unit 85 calculates the driving force of the vehicle (the driving force at the front wheels W _FL and W _FR ) based on the gear ratio input from the gear ratio determination unit 84 and the engine torque T _ENG, and the driving force distribution amount Input to the calculation unit 86.
Then, the driving force distribution amount calculation unit 86 integrates the driving force and the turning amount (yaw moment), and calculates the difference ΔD1 of the driving force distribution that the left and right driving force distribution device should distribute to the left and right front wheels W _FL and W _FR. Calculate and input to the adder 88.

The driving force distribution amount conversion unit 87 uses the difference Δγ _A between the reference yaw rate γ _TA and the actual yaw rate γ input from the subtraction unit 93 described later as the feedback control unit 73, for example, the actual yaw rate γ and the driving force distribution amount calculation unit. Referring to the driving force distribution difference ΔD1 calculated in 86, the driving force distribution feedback difference ΔD_FB is calculated. This is a method of calculating the feedback difference ΔD_FB of the driving force distribution approximately by proportional correction assuming that the difference ΔD1 of the driving force distribution corresponds to the vehicle running state in which the current actual yaw rate γ is generated. The driving force distribution feedback difference ΔD_FB calculated by the driving force distribution amount conversion unit 87 is input to the adding unit 88, and is added to the driving force distribution difference ΔD1 by the adding unit 88. (Distribution control information) ΔD2 is input to the signal converter 90.

Signal converting unit 90 supplies hydraulic pressure necessary to obtain the difference ΔD2 of the driving force distribution to be outputted to the left hydraulic clutch C _L or the right hydraulic clutch C _R, the linear solenoid 167 in the hydraulic circuit 28 Generate and control electrical signals. Further, the left and right turning decision unit 89, based on the turning amount inputted from the turning amount calculating unit 83 performs the determination of the turning direction, the left shift solenoid valve 168 to engage the left hydraulic clutch C _L during left turning _L energized, at the time of turning right to energize the right shift solenoid valve 168 _R to engage the right hydraulic clutch C _R.

Incidentally, the hydraulic circuit 28, the linear solenoid 167, the left shift solenoid valve 168 _L and the right shift solenoid valve 168 _R in the present embodiment are the linear solenoid 67 and the left shift solenoid in the hydraulic circuit H described in JP-A-09-309357. It corresponds to the valve 68 _L and the right shift solenoid valve 68 _R. Reference numerals 151 and 160 denote a hydraulic pump and an oil reservoir, which similarly correspond to the pump 51 and the oil reservoir 60 described in Japanese Patent Laid-Open No. 09-309357.

The feedback control unit 73 includes a reference yaw rate calculation unit 91 and a subtraction unit 93.
The reference yaw rate calculation unit 91 has three-dimensional map data 91a of the steering wheel operation angle θ _H , the lateral acceleration α _Y , and the vehicle speed VS stored in advance in the ROM, and the steering wheel operation angle θ _H , the lateral acceleration α _Y , the vehicle speed. The reference yaw rate γ _TA is calculated based on the three-dimensional map data 91 a with reference to VS, and is input to the subtracting unit 93.
The subtraction unit 93 calculates a difference Δγ _A (= γ _TA −γ) between the reference yaw rate γ _TA calculated by the reference yaw rate calculation unit 91 and the actual yaw rate γ, and inputs the difference Δγ _A (= γ _TA −γ) to the driving force distribution amount conversion unit 87. To do.

With such a configuration of the feedforward control unit 71 and the feedback control unit 73, for example, when the difference ΔD2 in the driving force distribution becomes excessive and an oversteer tendency occurs in the vehicle, the adder 88 cancels the oversteer tendency. Therefore, ΔD1 is reduced by the feedback amount ΔD_FB of the driving force distribution to reduce the turning amount, that is, the yaw moment is corrected in the restoring direction to be ΔD2.
Conversely, when the difference ΔD2 in the driving force distribution becomes too small and an understeer tendency occurs in the vehicle, ΔD1 is increased by the feedback difference ΔD_FB in the driving force distribution in order to eliminate the understeer tendency, that is, the yaw amount is increased. The moment is corrected in the turning direction to ΔD2.
Thus, the driving force distribution amount distributed to the left and right front wheels W _FL and W _FR by the driving force transmission device T is controlled by both feedforward control and feedback control.

Here, the reference yaw rate calculation unit 63 of the rear wheel toe angle control ECU 36 and the reference yaw rate calculation unit 91 of the left / right driving force distribution control ECU 37 have three-dimensional map data 63a and 91a having the same contents. , reference yaw rate gamma _TB output from respectively the same value as gamma _TA, reference yaw rate gamma _TB in subtraction unit 64,93, γ _TA and the difference [Delta] [gamma] _B between the actual yaw rate gamma, and [Delta] [gamma] _a is also the same value . When the rear wheel toe angle control ECU 36 and the left / right driving force distribution control ECU 37 determine the understeer state and the oversteer state, the same determination result is obtained.

(Control in the driving force distribution amount control state monitoring unit and the second correction unit)
Next, the functions of the driving force distribution amount control state monitoring unit 75 of the left and right driving force distribution control ECU 37 and the second correction unit 67 of the rear wheel toe angle control ECU 36, which are features of the present embodiment, will be described with reference to FIGS. The description will be given with reference.
4 and 5 are flowcharts showing the flow of target toe angle correction control in the second correction unit of the rear wheel toe angle control ECU.

  As shown in FIG. 3, the driving force distribution amount control state monitoring unit 75 uses the left and right driving force distribution difference ΔD2 output from the adding unit 88 as the left and right driving force distribution control information for a certain period, for example, several milliseconds or less. Sampling is performed at a period and input to the second correction unit 67 of the rear wheel toe angle control ECU 36.

Detailed functions of the second correction unit 67 will be described with reference to the flowcharts of FIGS.
The processing in the second correction unit 67 is performed at a constant cycle, for example, at a cycle of several milliseconds or less.
In step S01, a predetermined number of moving average values of the difference ΔD2 between the left and right driving force distributions are stored in a predetermined number N, for example, 2 or 3, in a time series, and a change tendency between the plurality of moving average values is stored. In order to make a determination in step S06 to be described later, an initial value n = 0 is set to obtain N moving average values.

  In step S02, a predetermined number of moving average values of the difference ΔD2 between the left and right driving force distributions input from the driving force distribution amount control state monitoring unit 75 are calculated, and the volatile memory of the rear wheel toe angle control ECU 36, For example, it is stored in a FIFO (Fast-In Fast-Out) memory. Here, the predetermined number used for calculating the moving average value of the difference ΔD2 in the left / right driving force distribution is, for example, about five. This uses a moving average value on the assumption that there is fluctuation in the value of the difference ΔD2 in the left / right driving force distribution.

In step S03, n = n + 1, and in step S04, it is checked whether n is N or more (n ≧ N). If n is greater than or equal to N (Yes), the process proceeds to step S05. If n is less than N (No), the process returns to step S02 and is repeated.
In step S05, the steering wheel operation angle θ _H , the standard yaw rate γ _TB calculated by the standard yaw rate calculation unit 63, and the difference Δγ _B (= γ _TB −γ) between the standard yaw rate γ _TB calculated by the subtraction unit 64 and the actual yaw rate. Then, the target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} corrected by the first correction unit 66 are read (“handle operation angle θ _H , standard yaw rate γ _TB , Δγ _B (= γ _TB −γ), target Toe angle θ _{TRT (L1)} , θ _{TRT (R1)} reading ”).

In step S06, it is determined whether the left / right driving force distribution information indicates yaw rate increase control (control for increasing the absolute value of yaw rate). This determination is easily made based on whether or not there is a change in the direction of increasing the yaw moment in the turning direction indicated by the reference yaw rate γ _TB between the moving average values of the difference ΔD2 values of N time-dependent left and right driving force distributions. Can be judged. If the yaw rate increase control is indicated (Yes), the process proceeds to step S07. If not (No), the process proceeds to step S09 according to the connector (A).

In step S07, whether γ _TB is negative and Δγ _B is a predetermined negative threshold −ε ₁ or less, or γ _TB is positive and Δγ _B is a predetermined positive threshold ε ₁ or more. (“Γ _TB is positive and Δγ _B ≧ −ε ₁ , or γ _TB is positive and Δγ _B ≧ ε ₁ ”).
Here, the above-mentioned predetermined value ε ₁ is a positive value, and the absolute value of the actual yaw rate γ indicating the turn in the same direction is smaller than the absolute value of the reference yaw rate γ _TB , and it is determined as the predetermined understeer state. Set a value suitable for
By the way, the yaw rate for the left turn is a negative value, and the yaw rate for the right turn is a positive value.

If Yes in step S07, the process proceeds to step S09 according to the connector (A). If No in step S07, the process proceeds to step S08.
In step S08, it is determined whether or not the target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} output by the first correction unit 66 read in step S05 are opposite in phase to the steering wheel operation angle θ _H read in step S05. judge. If the steering wheel operation angle θ _H is in reverse phase (Yes), the process proceeds to step S10 according to the connector (B). If the steering wheel operation angle θ _H is not in reverse phase (No), the step is performed according to the connector (A). Proceed to S09.

In step S09, the target toe angle θ _{TRT (L2)} = θ _{TRT (L1)} and the target toe angle θ _{TRT (R2)} = θ _{TRT (R1)} are set, and then the process proceeds to step S11.
In step S10, the target toe angle θ _{TRT (L2)} = 0 and the target toe angle θ _{TRT (R2)} = 0 are set, and then the process proceeds to step S11.

That is, when the difference ΔD2 in the left and right driving force distribution from the driving force distribution amount control state monitoring unit 75 indicates the increase control of the absolute value of the yaw rate in step S06, the understeer state equal to or greater than the predetermined value is further determined in step S07. If the understeer state is greater than or equal to a predetermined value, the target toe angle θ remains unchanged from the target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} of the reverse phase output from the first correction unit 66. _{TRT (L2)} and _{θTRT (R2)} are output to the phase delay compensation unit 68, and the target toe angles θTRT _(L2) and θTRT _(R2) subjected to the phase delay processing are converted into the rear wheel toe angle change control ECU 42L, Input to 42R. Therefore, in the understeer state exceeding a predetermined level, the yaw moment is added by the reverse phase control of the rear wheel toe angle, assuming that the yaw moment control by the left / right driving force distribution control is saturated.

In step S06, even when the difference ΔD2 between the left and right driving force distributions from the driving force distribution amount control state monitoring unit 75 indicates the increase control of the absolute value of the yaw rate, the understeer state is less than the predetermined in step S07. Cancels out-of-phase target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} output from the first correction unit 66, and sets the target toe angle θ _{TRT (L2)} = θ _{TRT (R2)} = 0. Output to the delay compensation unit 68. Therefore, in the understeer state less than the predetermined value, the yaw moment control by the left / right driving force distribution control is not saturated, and the reverse phase control of the rear wheel toe angle is stopped.

  In step S11, a predetermined number of moving average values of the difference ΔD2 in the left / right driving force distribution that have passed the most time are deleted from the storage, that is, deleted from the volatile memory. In step S12, a predetermined number of new moving average values of the left and right driving force distribution difference ΔD2 are stored, that is, stored in the volatile memory. Thereafter, the process returns to step S05 according to the connector (C) and the process is repeated.

According to this embodiment, the clutch C _L through the hydraulic circuit 28 by the left and right driving force distribution control ECU 37, driving force transmission device T by the operation control of the C _R is the absolute value of which increases the yaw rate of the turning side (yaw rate When the rear wheel toe angle control ECU 36 determines that the understeer state is less than a predetermined value, the rear wheel toe angle control ECU 36 determines the toe angle of the rear wheels W _RL and W _RR as the front wheel W _FL and W _FR . Since it is not controlled in the opposite direction to the direction, it is possible to prevent the yaw moment control by the driving force transmission device T and the yaw moment control by the rear wheel toe angle control from overlapping, thereby preventing excessive yaw moment control and turning the vehicle. The stabilization of movement can be controlled.

When the driving force transmission device T is operating in a direction to increase the yaw rate on the turning side, the rear wheel toe angle control ECU 36 determines that the rear wheel W _RL , W _Since it is allowed to control the toe angle of _{RR in} the opposite phase to the direction of the front wheels W _FL and W _FR , the yaw moment control by the driving force transmission device T is saturated. It can be supplemented by moment control, and stabilization control of the turning motion of the vehicle can be performed.

The correction by the second correction unit 67 sets a low speed threshold for the vehicle speed VS. For example, when the speed is less than 10 km / h, the second correction unit 67 does not operate when the vehicle is turned in a narrow space such as a garage. 2 The correction unit 67 operates to set the rear wheel target toe angle θ _{TRT (L2)} = θ _{TRT (R2)} = 0, that is, from step S07 in the flowcharts of FIGS. 4 and 5 to step S08 and step S10. It is possible to prevent migration.

Further, when the driving force transmission device T is operating in the direction of increasing the yaw rate on the turning side (increasing the absolute value of the yaw rate), the rear wheel toe angle control ECU 36 determines that the understeer state is less than a predetermined value. 4 and FIG. 5, the process proceeds from step S07 to step S08 and step S09, and the target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} are in phase with the directions of the front wheels W _FL and W _FR . Alternatively, if it is ± 0 °, the target toe angles θ _{TRT (L2)} and θ _{TRT (R2)} are allowed as they are, so that the in-phase control of the rear wheel toe angle when changing the lane can be performed without any problem.
In step S08, even when the target toe angles θ _{TRT (L1)} and θ _{TRT (R1)} are toe-in, the target toe angles θ _{TRT (L2)} and θ _{TRT (R2)} may be allowed as they are.

  Further, according to the present embodiment, the control ECU is provided in each of the left and right driving force distribution control ECU 37 and the rear wheel toe angle control ECU 36 as in the prior art, and for example, the reference yaw rate is calculated, and the actual yaw rate is determined as the reference. Driving force distribution amount control for obtaining a left and right driving force distribution difference ΔD2 as left and right driving force distribution control information in the control ECU 37 of the left and right driving force distribution device even if it is based on a program for controlling the yaw moment so as to match the yaw rate. A state monitor unit 75 is added, and the obtained left / right driving force distribution control information is output to the second correction unit 67 added to the rear wheel toe angle control ECU 36, and the target toe angle is corrected according to the left / right driving force distribution control state. Therefore, a subprogram is added to the control program developed independently for the conventional left / right driving force distribution control ECU and the rear wheel toe angle control ECU. By adding over Chin program can be configured to a vehicle motion control system the rear wheel toe angle control device cooperative control to the left and right driving force distribution device at low cost.

DESCRIPTION OF SYMBOLS 21 Front-wheel steering apparatus 21a Steering handle 24 EPS motor 25 Steering torque sensor 26 Motor drive circuit 27 Engine control ECU (right-and-left driving force distribution apparatus)
28 Hydraulic circuit (left and right driving force distribution device)
29 Brake control ECU
30FL, 30FR, 30RL, 30RR Wheel speed sensor 31 Yaw rate sensor (vehicle running state information acquisition means)
32 lateral acceleration sensor (vehicle running state information acquisition means)
33 Steering wheel operation angle sensor (vehicle running state information acquisition means)
34 Motor rotation angle sensor 35 EPS control ECU
36 Rear wheel toe angle control ECU (rear wheel toe angle control device)
37 Left / right driving force distribution control ECU
41L, 41R Rear wheel toe angle change device 42L, 42R Rear wheel toe angle change control ECU (rear wheel toe angle control device)
43L, 43R Actuator 44L, 44R Rear wheel toe angle sensor 46 Hydraulic circuit 49 Communication line 51 Vehicle speed calculation unit (vehicle running state information acquisition means)
53 ABS control unit 55 EPS control unit 61 Steering wheel operation angle differentiation unit 62 Target toe angle calculation unit (target toe angle setting means)
62a Target toe angle map data 63 Standard yaw rate calculation unit (standard yaw rate calculation means)
63a Three-dimensional map data 64 Subtraction unit (yaw rate deviation calculating means)
65 Feedback correction amount calculation unit 66 First correction unit (target toe angle setting means)
67 Second correction unit (target toe angle correction means)
68 Phase lag compensation unit 71 Feedforward control unit 73 Feedback control unit 75 Driving force distribution amount control state monitoring unit (right and left driving force distribution control state acquisition means)
DESCRIPTION OF SYMBOLS 81 Lateral acceleration determination part 82 Lateral acceleration estimation part 83 Turning amount calculation part 84 Gear ratio judgment part 85 Driving force calculation part 86 Driving force distribution amount calculation part 87 Driving force distribution amount conversion part 88 Addition part 89 Left / right turning determination part 90 Signal conversion Unit 91 Standard yaw rate calculation unit 91a Three-dimensional map data 93 Subtraction unit ΔD2 Difference in left and right driving force distribution (left and right driving force distribution control information)
α _Y lateral acceleration (vehicle running state information)
γ Actual yaw rate (vehicle running state information)
θ _H Steering angle (Vehicle running state information)
T drive force transmission device (left and right drive force distribution device)
VS vehicle speed (vehicle running state information)

Claims (4)

Depending on the operating angle of the left and right driving force distribution device that generates a yaw moment in the vehicle by distributing different driving forces to the left and right driving wheels of the vehicle, and the steering handle that changes the direction of the front wheels that are the steered wheels of the vehicle A rear wheel toe angle control device that changes the toe angle of the rear wheel, and a vehicle motion control system comprising at least
When the left and right driving force distribution device is operating in a direction to increase the yaw rate in the turning direction of the vehicle,
The rear wheel toe angle control device does not control a toe angle of the rear wheel in a phase opposite to the direction of the steered wheel. Further, vehicle travel state information acquisition means for acquiring vehicle travel state information including at least the speed of the vehicle, the operation angle of the steering handle, and the actual yaw rate of the vehicle;
Normative yaw rate calculating means for calculating a normative yaw rate based on at least the speed of the vehicle and the operating angle of the steering wheel in the vehicle driving state information acquired by the vehicle driving state information acquiring unit;
A yaw rate deviation calculating means for acquiring a deviation between the reference yaw rate calculated by the reference yaw rate calculating means and the acquired actual yaw rate;
The rear wheel toe angle control device may also control the toe angle of the rear wheel in a phase opposite to the direction of the steered wheel when the deviation acquired by the yaw rate deviation calculating means is equal to or greater than a predetermined threshold. The vehicle motion control system according to claim 1. Further, vehicle travel state information acquisition means for acquiring vehicle travel state information including at least the speed of the vehicle, the operation angle of the steering handle, and the actual yaw rate of the vehicle;
Left and right driving force distribution control state acquisition means for acquiring the left and right driving force distribution control state of the left and right driving force distribution device;
Target toe angle setting means for setting a target toe angle of the rear wheel based on at least the speed of the vehicle and the operating angle of the steering handle in the vehicle driving state information acquired by the vehicle driving state information acquiring means; ,
A target toe angle correcting unit that corrects the set target toe angle based on left and right driving force distribution control information indicating a left and right driving force distribution control state from the left and right driving force distribution control state acquisition unit;
When the left and right driving force distribution control information acquired by the left and right driving force distribution control state acquisition means indicates an operation in a direction to increase the yaw rate in the turning direction of the vehicle in the left and right driving force distribution device,
The target toe angle correcting means makes the toe angle of the rear wheel substantially zero when the target toe angle output from the target toe angle setting means is in a phase opposite to the direction of the steered wheel. The vehicle motion control system according to claim 1. Further, normative yaw rate calculating means for calculating a normative yaw rate based on at least the speed of the vehicle and the operating angle of the steering wheel in the vehicle traveling state information acquired by the vehicle traveling state information acquiring unit;
A yaw rate deviation calculating means for acquiring a deviation between the reference yaw rate calculated by the reference yaw rate calculating means and the acquired actual yaw rate;
The target toe angle correcting means also allows to control the toe angle of the rear wheel in a phase opposite to the direction of the steered wheel when the deviation acquired by the yaw rate deviation calculating means is equal to or greater than a predetermined threshold value. The vehicle motion control system according to claim 3.

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