Drive control device for vehicle

Abstract

In the present invention, a main control unit 20 for a vehicle 1 comprises a torque vectoring control unit 22 that variably controls the drive torque of right and left front wheels 3, 4 in a range equal to or lower than an upper limit value TA, and a torque steering suppression unit 26 that suppresses torque steering by performing increase / decrease control on an assist torque generated by an electric power steering device 25, with respect to actuation of the torque vectoring control unit 22. The main control unit is provided with a regulation control unit 31 that computes an EPS control suppression degree S EPS, which is a suppression degree of the torque steering in the torque steering suppression unit 26, and that also suppresses the actuation of the torque vectoring control unit 22 on the basis of the actuation state of the torque steering suppression unit 26, including the EPS control suppression degree S EPS.

Description

Vehicle drive control device

[0001] The present invention relates to a drive control device for a vehicle that is capable of steering assist for the front wheels of the vehicle and torque control for the left and right front wheels.

[0002] In order to improve the cornering performance of a vehicle, a differential gear with a limited slip differential (LSD) and a torque vectoring device have been developed. Some front-wheel drive vehicles, such as front-wheel drive vehicles and four-wheel drive vehicles, are equipped with an LSD or a torque vectoring device on the front wheel side. For example, the vehicle described in Patent Document 1 has an LSD on the front drive shaft (front axle) of the vehicle, and is also equipped with a power steering device that assists the steering force of the front wheels. In a vehicle with an LSD on the front axle, the operation of the LSD affects the steering force, which can cause a driver to feel uncomfortable due to so-called torque steer.

[0003] Therefore, Patent Document 1 discloses a technique for applying an assist torque so as to cancel out torque steer by controlling a power steering device.

[0004] JP 2012-57639 A

[0005] However, in a vehicle in which the power steering device is controlled to cancel torque steer caused by operation of the limited slip differential as described above, if it is difficult to apply an appropriate assist torque due to a malfunction of the power steering device or the like, torque steer may not be sufficiently eliminated, causing the driver to feel uncomfortable. Also, in a vehicle equipped with a torque vectoring device on the front wheels of the vehicle, it is desirable to control the power steering device to cancel torque steer, as in a vehicle with an LSD. However, even in a vehicle equipped with a torque vectoring device, if it is difficult to apply an appropriate assist torque due to a malfunction of the power steering device or the like, torque steer may not be sufficiently eliminated, causing the driver to feel uncomfortable.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a drive control device for a vehicle that has a torque control device such as an LSD or a torque vectoring device on the left and right front wheel sides of the vehicle, and also has a torque steer suppression device that cancels out torque steer by operating a power steering device, and that is capable of suppressing the uncomfortable feeling caused by torque steer when the operation of the torque steer suppression device is suppressed.

[0007] In order to achieve the above object, the drive control device of the present invention is a vehicle drive control device comprising: a front wheel torque control device that controls drive torque of the left and right front wheels; a power steering device that applies an assist torque to the steering of the left and right front wheels; and a torque steer suppression device that suppresses torque steer by increasing or decreasing the assist torque by the power steering device in response to the operation of the front wheel torque control device, and is characterized by having an operation state determination unit that determines the operation state of the torque steer suppression device, and a control unit that suppresses the operation of the front wheel torque control device based on the operation state of the torque steer suppression device.

[0008] As a result, based on the operating state of the torque steer suppression device, for example, when the suppression of torque steer by the torque steer suppression device is insufficient, the operation of the front wheel torque control device can be suppressed, thereby making it possible to suppress torque steer associated with the operation of the front wheel torque control device. Preferably, the front wheel torque control device can variably control the torque difference between the left and right front wheels within a range not exceeding an upper limit value, and the control unit may set the upper limit value to a first upper limit value that is set based on the degree of torque steer suppression in the torque steer suppression device.

[0009] Thus, by setting the upper limit of the torque difference between the left and right front wheels in the front wheel torque control device to a first upper limit based on the degree of torque steer suppression by the torque steer suppression device, for example, when the torque steer suppression by the torque steer suppression device is insufficient, it is possible to suppress an increase in torque steer by the front wheel torque control device and appropriately reduce torque steer. Preferably, there is provided a failure determination unit which determines a failure of the torque steer suppression device, and when the failure is determined, the control unit sets the upper limit to a second upper limit which is lower than the first upper limit.

[0010] As a result, if the torque steer suppression device fails and is unable to suppress torque steer, the front wheel torque control device can significantly reduce the upper limit value of the torque difference between the left and right front wheels to the second upper limit value, thereby significantly reducing torque steer. Preferably, the vehicle is a four-wheel drive vehicle having a front and rear axle drive control unit that variably controls the drive torque of the front axles and the drive torque of the rear axles, the front wheel torque control device is a mechanical differential with a differential limiting mechanism that distributes the drive torque of the front axles to the left and right front wheels while allowing a differential between the left and right front wheels and limits the differential between the left and right front wheels, and the control unit can set the upper limit value of the drive torque of the front axles to a third upper limit value that is set on the basis of the degree of torque steer suppression in the torque steer suppression device.

[0011] Thus, by setting the upper limit of the drive torque of the front axle to the third upper limit based on the degree of torque steer suppression by the torque steer suppression device, for example, when the suppression of torque steer by the torque steer suppression device is insufficient, the drive torque of the front axle is suppressed to prevent an increase in torque steer, and torque steer can be appropriately reduced. Preferably, there is provided a failure determination unit which determines a failure of the torque steer suppression device, and when the failure is determined, the control unit sets the upper limit of the drive torque of the front axle to a fourth upper limit which is lower than the third upper limit.

[0012] As a result, when the torque steer suppression device fails and is unable to suppress torque steer, the front wheel torque control device can greatly reduce the drive torque of the front wheels to the fourth upper limit value, thereby significantly reducing the occurrence of torque steer. Preferably, the vehicle includes a required driving torque calculation unit that calculates a required driving torque of the vehicle, and an actual driving torque estimating unit that estimates an actual driving torque of the vehicle, and the control unit suppresses operation of the front wheel torque control device based on the operating state of the torque steer suppression device, and when the actual driving torque differs from the required driving torque, compensation is made by controlling the drive torque of the rear wheels of the vehicle or by controlling a braking device of the vehicle.

[0013] As a result, if the operation of the front wheel torque control device is suppressed and the vehicle's actual driving torque becomes excessive or insufficient compared to the required driving torque, it is possible to match the actual driving torque to the required driving torque by controlling the drive torque of the vehicle's rear wheels or by controlling the braking device.

[0014] According to the drive control device for a vehicle of the present invention, the operation of the front wheel torque control device is suppressed based on the operating state of the torque steer suppression device, thereby making it possible to suppress torque steer associated with the operation of the front wheel torque control device, and therefore to suppress the discomfort caused by torque steer when the operation of the torque steer suppression device is suppressed.

[0015] 1 is a schematic configuration diagram of an electric vehicle equipped with a drive control device of a first embodiment of the present invention. 2 is a block diagram showing the schematic configuration of the drive control device of the first embodiment. 3 is a schematic configuration diagram of an electric vehicle equipped with a drive control device of a second embodiment of the present invention. 4 is a block diagram showing the schematic configuration of the drive control device of the second embodiment.

[0016] 1 is a schematic diagram of a vehicle 1 equipped with a drive control device according to a first embodiment of the present invention. The vehicle 1 of the first embodiment employing the drive control device of the present invention is an electric vehicle in which left and right front wheels 2, 3 are driven by an electric front motor 7. The front motor 7 is capable of driving a drive shaft (front axle 9) for the left and right front wheels 2, 3 via a reduction gear 8. The front axle 9 is equipped with a front differential gear (hereinafter referred to as a front differential 10) that transmits power from the front motor 7 to the left and right front wheels 2, 3 while absorbing the difference in rotational speed between the left and right front wheels 2, 3.

[0017] The front differential 10 is an electronically controlled differential gear that can vary and control the distribution of driving force between the left and right front wheels 2, 3. The main control unit 20 (required driving torque calculation unit, actual driving torque estimation unit) is a control unit for the entire vehicle, and is composed of input / output devices, memory devices (ROM, RAM, non-volatile RAM, etc.), a central processing unit (CPU), a timer, etc.

[0018] The vehicle 1 is equipped with various sensors (not shown), such as a wheel speed sensor that detects the rotational speed of each wheel 2 to 5, a steering angle sensor that detects the steering angle of the front wheels 2 and 3, a vehicle speed sensor, a yaw rate sensor that detects the actual yaw rate of the vehicle 1, and an accelerator position sensor that detects the amount of accelerator operation, and the detection information of each of these sensors is input to the main control unit 20.

[0019] The main control unit 20 has a function of calculating the required driving torque of the vehicle 1 based on the accelerator operation amount, etc., and has a function of controlling the operation of the front motor 7 based on the required driving torque, as well as estimating the actual driving torque of the vehicle 1 based on detection information from various sensors, for example. The vehicle 1 is equipped with a torque vectoring device that controls the distribution of driving force to the left and right front wheels 2, 3. The torque vectoring device is executed by controlling the operation of the front differential 10 using a torque vectoring control unit 22 (front wheel torque control device) provided in the main control unit 20.

[0020] The torque vectoring control unit 22 receives input of each wheel speed, steering angle, vehicle speed, and actual yaw rate, and controls the drive of the front differential 10 to distribute drive force between the left and right front wheels 2, 3 so that the actual yaw rate of the vehicle 1 approaches the target yaw rate. The vehicle 1 is equipped with an electric power steering device 25 (EPS) that assists the steering force of the front wheels. The electric power steering device 25 is capable of variably controlling the steering assist force based on a control signal from the main control unit 20. The electric power steering device 25 is equipped with various safety devices, and a maximum value of the steering assist force of the electric power steering device 25 (EPS maximum control allowance amount) is set in response to a failure or the like, thereby regulating the steering assist force.

[0021] The main control unit 20 is provided with a torque steer suppression section 26 (torque steer suppression device) that controls the steering assist force of the electric power steering device 25 so as to cancel out torque steer generated by operation of the torque vectoring device. The torque steer suppression section 26 may control the operation of the electric power steering device 25 so that the actual steering torque coincides with the required steering torque, based on the actual steering torque detected by a steering torque sensor, for example, and the drive current of the actuator in the electric power steering device 25.

[0022] 2 is a block diagram showing the control details of the front torque control executed by the main control unit 20. The main control unit 20 according to the first embodiment includes a restriction control unit 31 (control unit) that performs restriction control of the torque vectoring control. The restriction control unit 31 includes an EPS control suppression degree calculation unit 32 (operation state determination unit), a first torque difference upper limit calculation unit 33, a torque difference compensation control prohibition / suppression determination unit 34 (fault determination unit), a torque difference upper limit setting unit 35 (control unit), and a torque difference suppression flag output unit 36.

[0023] The EPS control suppression degree calculation unit 32 receives the EPS maximum control allowable amount from the electric power steering device 25 and calculates the EPS control suppression degree SEPS. The EPS control suppression degree SEPS is expressed in %, and an EPS control suppression degree SEPS of 100% indicates a state in which the electric power steering device 25 can provide 100% assist force (no assist force suppression), and an EPS control suppression degree SEPS of 0% indicates a state in which the electric power steering device 25 cannot provide assistance (assist force = 0). The EPS control suppression degree SEPS may be set continuously or in stages between 0 and 100%.

[0024] The first torque difference upper limit calculation unit 33 calculates a first torque difference upper limit value TA1 (first upper limit value) of the torque vectoring device based on the EPS control suppression degree SEPS calculated by the EPS control suppression degree calculation unit 32. The torque difference upper limit value TA of the torque vectoring device is the upper limit value of the torque difference between the left and right front wheels 2, 3 when the torque vectoring control unit 22 controls the front differential 10.

[0025] For example, as shown in the graph in FIG. 2 , the first torque difference upper limit TA1 reaches its maximum value when the EPS control suppression level SEPS is 60% or higher, decreases as the EPS control suppression level SEPS decreases from 60%, and reaches 0 when the EPS control suppression level SEPS is 30% or lower. The torque difference compensation control prohibition / suppression determination unit 34 is capable of receiving abnormality determination signals from various sensors used in connection with the electric power steering device 25 and abnormality signals in the CAN that transmits signals between the control units. When these abnormality signals are input, the torque difference compensation control prohibition / suppression determination unit 34 outputs a second torque difference upper limit TA2 (second upper limit). The second torque difference upper limit TA2 is a fixed value that is set to, for example, 0 or a value close to 0. When no abnormality signal is input, the torque difference compensation control prohibition / suppression determination unit 34 outputs a value equal to or greater than the maximum value of the first torque difference upper limit TA1.

[0026] The torque difference upper limit setting unit 35 compares the first torque difference upper limit TA1 calculated by the first torque difference upper limit calculation unit 33 with the second torque difference upper limit TA2 output from the torque difference compensation control prohibition / suppression determination unit 34, and outputs the smaller value as the torque difference upper limit TA. The torque difference upper limit TA is output to the torque vectoring control unit 22 and is used as the upper limit of the torque difference when distributing torque to the left and right front wheels 2, 3 in the torque vectoring device.

[0027] When the torque difference upper limit value TA output from the torque difference upper limit value setting unit 35 is equal to or less than an appropriately set predetermined value, the torque difference suppression flag output unit 36 ​​outputs a torque difference suppression flag indicating that the torque vectoring control unit 22 is restricting the upper limit value of the torque difference between the left and right front wheels 2, 3. The torque difference suppression flag is used, for example, to turn on a warning light provided on the instrument panel of the vehicle 1 or in other control devices of the vehicle 1. Note that the restriction control unit 31 (control unit) that performs restriction control of the torque vectoring control may be implemented in the EPS and configured to transmit the calculation results to the main control unit 20.

[0028] Furthermore, when the torque difference between the left and right front wheels 2, 3 required in torque vectoring control exceeds the upper limit value set by the restriction control unit 31, the restriction control unit 31 may compensate for the insufficient torque difference by controlling the braking forces of the brake devices 41-44 (braking devices) of the wheels 2-5 via the brake control unit 40 provided in the vehicle 1. As a result, even if the torque difference between the left and right front wheels 2, 3 is restricted in the restriction control unit 31 to suppress torque steer, the torque of the wheels 2-5 can be adjusted by controlling the brake devices 41-44, thereby ensuring the turning performance of the vehicle 1 required in torque vectoring control.

[0029] Furthermore, if the vehicle 1 is a four-wheel drive vehicle capable of rear-wheel drive along with the front wheels 2, 3, and has, for example, an electronically controlled differential on the rear axle that can distribute and control the drive torque of the left and right rear wheels 4, 5, when the upper limit of the torque difference between the left and right front wheels 2, 3 is restricted to a low value and the left and right torque difference required in torque vectoring control exceeds the upper limit, the torque difference between the left and right rear wheels 4, 5 may be controlled to compensate for the shortfall in the torque difference between the left and right front wheels 2, 3. In this way, even if the torque difference between the left and right front wheels 2, 3 is restricted to suppress torque steer, the torque of the left and right rear wheels 4, 5 can be controlled by controlling the drive torque difference between the left and right rear wheels 4, 5, thereby ensuring the cornering performance required in torque vectoring control.

[0030] Although the first embodiment described above is an electric vehicle in which the front wheels 2, 3 are driven by an electric front motor 7, the vehicle may alternatively be one in which the front wheels 2, 3 are driven by an engine. As described above, the vehicle 1 according to the first embodiment is provided with a torque vectoring device (torque vectoring control unit 22) that controls the drive torque of the left and right front wheels 2, 3 to improve the turning performance of the vehicle 1. The vehicle 1 also includes a torque steer suppression unit 26 that controls the assist torque provided by the electric power steering device 25 to suppress torque steer that occurs due to operation of the torque vectoring device.

[0031] In this embodiment, the operation of the torque vectoring control unit 22 is suppressed based on the operation state of the torque steer suppression unit 26, thereby suppressing torque steer that occurs due to the torque vectoring control when the suppression of torque steer by the torque steer suppression unit 26 is insufficient. More specifically, in the restriction control unit 31 provided in the main control unit 20, an EPS control suppression degree calculation unit 32 calculates an EPS control suppression degree SEPS, which is the degree of suppression of torque steer by the torque steer suppression unit 26, and a first torque difference upper limit value calculation unit 33 calculates a first torque difference upper limit value TA1 based on the EPS control suppression degree SEPS.

[0032] When the torque vectoring control unit 22 performs torque vectoring control, by limiting the upper limit value TA of the torque difference between the left and right front wheels 2, 3 to the first torque difference upper limit value TA1, it is possible to appropriately reduce torque steer in response to a case where the degree of torque steer suppression in the torque steer suppression unit 26 is insufficient. Furthermore, when the torque steer suppression unit 26 is in a failure state due to a sensor abnormality or the like, it is possible to significantly reduce torque steer by setting the upper limit value TA of the torque difference between the left and right front wheels 2, 3 in the torque vectoring control unit 22 to a second torque difference upper limit value TA2 (0 or a value close to 0) which is lower than the first torque difference upper limit value TA1.

[0033] Incidentally, by setting the lower of the first torque difference upper limit value TA1 and the second torque difference upper limit value TA2 as the torque difference upper limit value TA, torque steer can be reduced to a necessary and sufficient extent. In this way, when torque steer suppression by the torque steer suppression unit 26 is insufficient, torque steer occurring due to torque vectoring control can be suppressed by suppressing operation of the torque vectoring control unit 22, thereby making it possible to suppress the discomfort caused by torque steer. Furthermore, as described above, when the torque difference between the left and right front wheels 2, 3 is insufficient due to suppression of operation of the torque vectoring control unit 22, the braking devices 41 to 44 and the torque difference control of the rear wheels are performed to compensate for the insufficiency, thereby ensuring the cornering performance of the vehicle.

[0034] Furthermore, when the actual running torque of the vehicle 1 exceeds the required running torque due to the suppression of operation of the torque vectoring control unit 22, the restriction control unit 31 may suppress the actual running torque of the vehicle 1 by controlling the brake devices 41 to 44. Figure 3 is a schematic diagram of a vehicle 50 equipped with a drive control device according to a second embodiment of the present invention. Only the differences from the first embodiment will be described below.

[0035] A vehicle 50 of a second embodiment employing the drive control device of the present invention is an electric four-wheel drive vehicle in which the left and right front wheels 2, 3 are driven by an electric front motor 7, and the left and right rear wheels 4, 5 are driven by an electric rear motor 51. A front differential 52 (mechanical differential, front wheel torque control device) provided on the front axle 9, which is the drive shaft for the front wheels 2, 3, is a differential gear with a mechanical differential limiting mechanism that distributes drive force to the left and right front wheels, and the distribution of drive torque to the left and right front wheels 2, 3 can be switched, for example, by operation by the driver.

[0036] A rear axle 53, which is the drive shaft for the left and right rear wheels 4, 5, is provided with a mechanical rear differential gear (hereinafter referred to as rear diff 55) that distributes driving force from the rear motor 51 to the left and right rear wheels 4, 5 via a speed reducer 54. The vehicle 50 of this embodiment is provided with an electric power steering device 25, but is not provided with a torque vectoring device, i.e., a torque vectoring control unit 22.

[0037] The main control unit 60, which is a control device for the entire vehicle 50, is provided with a motor drive control unit 62 (front and rear axle drive control unit, front wheel torque control device) that controls the drive of the front motor 7 and rear motor 51. The motor drive control unit 62 controls the drive torque of the front motor 7 and rear motor 51, thereby controlling the drive torque of the front axle 9 and the drive torque of the rear axle 53.

[0038] 4 is a block diagram showing the control details of the front torque control executed by the main control unit 60. The main control unit 60 according to the second embodiment is provided with a restriction control unit 61 (control unit) that suppresses the front torque. The restriction control unit 61 is provided with an EPS control suppression degree calculation unit 32, a first front torque upper limit calculation unit 63, a torque difference compensation control prohibition / suppression determination unit 64 (fault determination unit), a front torque upper limit setting unit 65 (control unit), and a front torque suppression flag output unit 66.

[0039] The first front torque upper limit calculation unit 63 calculates a first front torque upper limit value TB1 (third upper limit value), which is the upper limit of the drive torque of the front motor 7, based on the EPS control suppression degree SEPS calculated by the EPS control suppression degree calculation unit 32. As shown in the graph in Figure 4, for example, the first front torque upper limit value TB1 reaches a maximum value when the EPS control suppression degree SEPS is 60% or higher, decreases as the EPS control suppression degree SEPS decreases from 60%, and becomes zero when the EPS control suppression degree SEPS is 30% or lower.

[0040] The torque difference compensation control prohibition / suppression determination unit 64 is capable of receiving abnormality determination signals from various sensors used in connection with the electric power steering device 25 and abnormality signals in the CAN that transmits signals between the control units, and when these abnormality signals are input, it outputs a second front torque upper limit value TB2 (fourth upper limit value). The second front torque upper limit value TB2 is a fixed value that is set to, for example, 0 or a value close to 0. When no abnormality signal is input, it outputs a value equal to or greater than the maximum value of the first front torque upper limit value TB1.

[0041] The front torque upper limit setting unit 65 compares the first front torque upper limit TB1 calculated by the first front torque upper limit calculation unit 63 with the second front torque upper limit TB2 output from the torque difference compensation control prohibition / suppression determination unit 64, and outputs the smaller value as the front torque upper limit TB. The front torque upper limit TB is output to the motor drive control unit 62 and used as the upper limit of the output torque of the front motor 7. As a result, the drive torque of the front axle 9 is restricted to a low value.

[0042] The front torque suppression flag output unit 66 outputs a front torque suppression flag indicating that the front torque is being suppressed when the front torque upper limit value TB output from the front torque upper limit value setting unit 65 is equal to or less than a predetermined value that is appropriately set. The front torque suppression flag is used, for example, to turn on a warning light provided on the instrument panel of the vehicle 1 or to other control devices of the vehicle 1.

[0043] Furthermore, if the setting of the front torque upper limit value causes a shortage of driving torque for the entire vehicle, the restriction control unit 61 may increase the driving torque of the rear motor 51 to compensate for the shortage. As a result, even if the restriction control unit 61 suppresses the front torque (driving torque of the front wheels) to suppress torque steer, the driving torque of the left and right rear wheels 4, 5 can be increased to ensure the driving torque for the entire vehicle.

[0044] As described above, the vehicle 50 according to the second embodiment is a four-wheel drive vehicle having the front motor 7 and the rear motor 51, and is capable of variably controlling the drive torque of the front axle 9 and the drive torque of the rear axle 53 by controlling the drive of the front motor 7 and the rear motor 51. In the second embodiment, the front axle 9 has a mechanical LSD, and torque steer generated by switching the operation of the front differential 52 is suppressed by the torque steer suppression unit 26.

[0045] In this embodiment, torque steer can be suppressed by suppressing the upper limit of the drive torque of the front axle 9 based on the operation state of the torque steer suppression section 26. More specifically, in the restriction control section 61 provided in the main control unit 20, an EPS control suppression degree calculation section 32 calculates an EPS control suppression degree SEPS, which is the degree of suppression of torque steer in the torque steer suppression section 26, and a first front torque upper limit value calculation section 63 calculates a first front torque upper limit value TB1 based on the EPS control suppression degree SEPS.

[0046] By limiting the drive torque of the front axle 9 to not more than the first front torque upper limit value TB1 when switching the operation of the front differential 52, it is possible to appropriately reduce torque steer in response to the case where the degree of torque steer suppression by the torque steer suppressing section 26 is insufficient. Furthermore, when the torque steer suppressing section 26 is in a malfunctioning state due to a sensor abnormality or the like, it is possible to significantly reduce torque steer by limiting the drive torque of the front axle to not more than the second torque difference upper limit value TA2 (0 or a value close to 0), which is lower than the first torque difference upper limit value TA1.

[0047] Incidentally, by setting the lower of the first front torque upper limit value TB1 and the second front torque upper limit value TB2 as the front torque upper limit value TB, torque steer can be reduced sufficiently as required. In this way, when torque steer suppression by the torque steer suppression unit 26 is insufficient, torque steer occurring due to the differential limiting of the front differential 52 can be suppressed by suppressing the drive torque of the front axle 9, thereby making it possible to suppress the discomfort caused by torque steer. Furthermore, as described above, when the drive torque of the front axle 9 is suppressed and the drive torque of the rear axle 53 is increased to compensate for the shortage, it is possible to ensure the driving force of the vehicle 50.

[0048] Although the description of the embodiment has been completed above, aspects of the present invention are not limited to the above embodiment. For example, in the first embodiment, if the vehicle 1 is a four-wheel drive vehicle that can also drive the rear axle 53, and the torque difference between the left and right front wheels 2, 3 is suppressed in the restriction control unit 31 to suppress torque steer, and if the drive torque of the entire vehicle is insufficient, the drive torque of the rear axle 53 may be increased to compensate for the shortage.

[0049] Furthermore, the details of the various controls may be changed as appropriate in the first and second embodiments. The present invention can be widely applied to vehicles equipped with a torque steer suppression device that suppresses torque steer generated by torque control of the front wheels of the vehicle using a power steering device.

[0050] 1, 50 Vehicle 10 Front differential (front wheel torque control device) 20, 60 Main control unit (required driving torque calculation unit, actual driving torque estimation unit) 22 Torque vectoring control unit (front wheel torque control device) 25 Electric power steering device (power steering device) 26 Torque steer suppression unit (torque steer suppression device) 31, 61 Regulation control unit (control unit) 32 EPS control suppression degree calculation unit (operation state determination unit) 34, 64 Torque difference compensation control prohibition / suppression determination unit (fault determination unit) 35 Torque difference upper limit value setting unit (control unit) 41 to 44 Brake device (braking device) 52 Front differential (front wheel torque control device) 62 Motor drive control unit (front and rear axle drive control unit) 65 Front torque upper limit value setting unit (control unit)

Claims

1. a front wheel torque control device that controls the drive torque of the left and right front wheels; a power steering device that applies an assist torque to the steering of the left and right front wheels; a torque steer suppression device that suppresses torque steer by increasing or decreasing the assist torque of the power steering device in response to the operation of the front wheel torque control device; A drive control device for a vehicle comprising: an operation state determination unit that determines a degree of torque steer suppression in the torque steer suppression device; a control unit that controls operation of the front wheel torque control device to suppress a torque difference between the left and right front wheels or a drive torque of the left and right front wheels based on an operation state of the torque steer suppression device. A vehicle drive control device characterized by:

2. The control unit suppresses the torque difference between the left and right front wheels to a first upper limit value or less that is variably set based on the degree of suppression of torque steer.

2. The vehicle drive control device according to claim 1.

3. a failure determination unit for determining a failure of the torque steer suppression device, When the malfunction is determined, the control unit suppresses the torque difference between the left and right front wheels to a second upper limit value that is lower than the first upper limit value.

3. The vehicle drive control device according to claim 2.

4. the vehicle is a four-wheel drive vehicle having a front and rear axle drive control unit that variably controls the drive torque of the front axle and the drive torque of the rear axle, the front wheel torque control device is a mechanical differential equipped with a differential limiting mechanism that distributes drive torque of the front axle to the left and right front wheels while allowing differential movement between the left and right front wheels, and limits differential movement between the left and right front wheels, The control unit suppresses the drive torque of the front axle to a third upper limit value or less that is set based on the degree of suppression of the torque steer.

2. The vehicle drive control device according to claim 1.

5. a failure determination unit for determining a failure of the torque steer suppression device, When the failure is determined, the control unit suppresses the drive torque of the front axle to a fourth upper limit value or less that is lower than the third upper limit value.

5. The vehicle drive control device according to claim 4.

6. a required traveling torque calculation unit that calculates a required traveling torque of the vehicle; an actual driving torque estimation unit that estimates an actual driving torque of the vehicle, The control unit suppresses operation of the front wheel torque control device based on the operating state of the torque steer suppression device, and when the actual driving torque differs from the required driving torque, compensates for the actual driving torque by controlling the drive torque of the rear wheels of the vehicle or by controlling a braking device of the vehicle.

2. The vehicle drive control device according to claim 1.