JP2005328680A - Travel control device for a four-wheel independent drive vehicle - Google Patents

Abstract

In a vehicle in which braking / driving force of four wheels can be controlled independently of each other, it is possible to deflect the vehicle regardless of whether a wheel having an abnormality in braking / driving force generating means is a front wheel or a rear wheel. Prevent appropriately.
When it is determined that an abnormality has occurred in the motor generator of any wheel (S40), the supply of control current to the wheel is stopped (S50), and the wheel in which the abnormality has occurred in the motor generator is changed to the front wheel. (S60), and when it is determined that the wheel in which the abnormality has occurred in the motor generator is the front wheel, the control current for the front wheel on the opposite side to the abnormal wheel over the relatively short T1 time. Is gradually reduced to 0, so that energization is finally stopped (S70, 80), and when it is determined that the wheel in which the motor generator has failed is the rear wheel, it takes a relatively long T2 time. When the control current for the front wheel on the opposite side to the abnormal wheel is gradually reduced to 0, the energization is finally stopped (S90, 100).
[Selection] Figure 4

Description

  The present invention relates to a vehicle travel control device, and more particularly to a vehicle travel control device capable of independently controlling the braking / driving forces of four wheels.

As one of vehicles that can control the braking / driving force of the four wheels independently of each other, for example, as described in the following Patent Document 1 relating to the application of the present applicant, A vehicle equipped with an in-wheel motor is conventionally known.
Japanese Patent Laid-Open No. 10-285891

  In a vehicle in which the braking / driving force of four wheels can be controlled independently of each other, such as the vehicle described in Patent Document 1, when an abnormality occurs in any one of the braking / driving force generating means, A difference occurs in the braking / driving force, and the vehicle is deflected due to the yaw moment caused by the braking / driving force difference acting on the vehicle. Therefore, if an abnormality occurs in the braking / driving force generating means for one of the wheels, the braking / driving force difference between the left and right wheels is reduced by bringing the braking / driving force of the wheel on the opposite side of the wheel closer to the braking / driving force of the abnormal wheel. There is a need to.

  In this case, as will be described in detail later, depending on whether the wheel in which the abnormality occurs in the braking / driving force generating means is the front wheel (steering wheel) or the rear wheel (non-steering wheel), the abnormality in the driving force generating means The influence on the deflection is different, and when the abnormal wheel is the front wheel, the deflection of the vehicle is abruptly larger than when the abnormal wheel is the rear wheel.

  For example, FIG. 6 shows the vehicle path deviation amount when an abnormality occurs in one braking / driving force generating means for the front wheels (solid line) and when an abnormality occurs in one braking / driving force generating means for the rear wheels (broken line). It is a graph which shows the example of change. As can be seen from FIG. 6, when an abnormality occurs in one of the braking / driving force generating means for the front wheels, the vehicle course shifts earlier than when an abnormality occurs in one of the braking / driving force generating means for the rear wheels. As a result, the amount of deviation in the course of the vehicle is large, and therefore, when an abnormality occurs in one braking / driving force generating means for one of the front wheels, it is earlier than when an abnormality occurs in one braking / driving force generating means for the rear wheel. It can be seen that the amount of deviation in the course of the vehicle exceeds the allowable limit.

  The difference in the course deviation of the vehicle is that when an abnormality occurs in one braking / driving force generating means of the front wheel, the yaw moment due to the braking / driving force difference between the left and right front wheels acts on the vehicle, and the braking / driving of the normal wheel When the normal wheels are steered by force, the left and right front wheels are steered, and the yaw moment due to the cornering force of the left and right front wheels also acts on the vehicle, but an abnormality occurs in one braking / driving force generating means of the rear wheels In this case, it is considered that this is because only the yaw moment due to the difference in braking / driving force between the left and right rear wheels acts on the vehicle.

  Therefore, in order to appropriately prevent the vehicle from deflecting when an abnormality occurs in the braking / driving force generating means, the braking / driving force of the opposite left and right wheels depends on whether the abnormal wheel is the front wheel or the rear wheel. The degree of approach, that is, the speed and amount of approach when the wheel is brought close to the braking / driving force of the abnormal wheel must be optimally controlled.

  The present invention has been made in view of the above-described problems in a vehicle that can control the braking / driving force of four wheels independently of each other. The main problem of the present invention is whether the abnormal wheel is a front wheel. When the braking / driving force generating means is abnormal by optimally controlling the approaching degree when the braking / driving force of the opposite wheel is brought close to the braking / driving force of the abnormal wheel depending on whether it is a rear wheel Is to properly prevent the vehicle's deflection.

  According to the present invention, the main problem described above is the configuration of claim 1, that is, the braking / driving force control means capable of independently controlling the braking / driving forces of four wheels, and the braking / driving force control of any one wheel. An abnormality that causes the braking / driving force of the wheel on the opposite side of the abnormal wheel to approach the braking / driving force of the abnormal wheel when an abnormality of the braking / driving force control means of any one wheel is detected. And when the abnormality occurs in the braking / driving force control means of the front wheel that is a steered wheel, the degree of approach of the braking / driving force by the abnormality processing means is abnormal in the braking / driving force control means of the rear wheel. This is achieved by a traveling control device for a four-wheel independent braking / driving vehicle characterized by being higher than the degree of approach of the braking / driving force by the abnormality processing means when it occurs.

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 1, the braking / driving force control means is provided for each wheel to control / brake the corresponding wheel. It is comprised so that a driving force generation means may be included (structure of Claim 2).

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 2, the braking / driving force generating means is incorporated in the wheel, and the kingpin offset of the front wheel is not zero. (Structure of claim 3).

  According to the present invention, in order to effectively achieve the main problems described above, in the configuration of claim 2, the braking / driving force generating means is mounted on the vehicle body of the vehicle and viewed in the vehicle longitudinal direction. The distance between the rotation center plane of the front wheel and the kingpin shaft at the height position of the rotation axis of the front wheel is configured not to be 0 (configuration of claim 4).

  According to the configuration of the first aspect, when the abnormality occurs in the braking / driving force control means for the front wheels that are the steering wheels, the degree of approach of the braking / driving force by the abnormality processing means is abnormal in the braking / driving force control means for the rear wheels. Since it is higher than the degree of approach of the braking / driving force by the abnormality processing means when it occurs, the right and left sides are opposite in both cases where the wheel where the abnormality occurs in the braking / driving force control means is the front wheel and the rear wheel It is possible to optimally control the degree of approach when bringing the braking / driving force of the side wheel closer to the braking / driving force of the abnormal wheel, thereby appropriately preventing the vehicle from deflecting when an abnormality occurs in the braking / driving force generating means. can do.

  According to the second aspect of the present invention, since the braking / driving force generating means for braking / driving the corresponding wheel is provided for each wheel, the left and right sides are opposite to the wheel on which the abnormality occurs in the braking / driving force control means. The degree of approach when the braking / driving force of the wheel is brought close to the braking / driving force of the abnormal wheel can be reliably and optimally controlled.

  According to the third aspect of the present invention, the braking / driving force generating means is incorporated in the wheel, the front wheel kingpin offset is not zero, and according to the fourth aspect of the present invention, the braking / driving force generating means is Since the distance between the front wheel rotation center plane and the kingpin shaft at the height position of the front wheel rotation axis when viewed in the vehicle longitudinal direction is not zero, the braking / driving force control of any front wheel When an abnormality occurs in the means, a difference occurs in the braking / driving force of the left and right front wheels including the wheel, and the wheel is steered by the braking / driving force of the wheel on the opposite side to the wheel where the abnormality has occurred. If the vehicle is steered and the yaw moment due to the difference in braking / driving force between the left and right front wheels and the yaw moment due to the steering of the left and right front wheels are applied to the vehicle, and if an abnormality occurs on one of the front wheels, Compared to The amount of deflection of the vehicle is large with quite early deflection of the vehicle is generated.

  According to the configuration of the third and fourth aspects, the degree of approach of the braking / driving force by the abnormality processing means when the abnormality occurs in the braking / driving force control means for the front wheels is abnormal in the braking / driving force control means for the rear wheels. The braking / driving force of the opposite left and right wheels is the same in both cases where the abnormal wheel is the front wheel and the rear wheel. It is possible to optimally control the degree of approach when approaching the braking / driving force of the abnormal wheel, thereby properly and reliably preventing vehicle deflection when an abnormality occurs in the braking / driving force generating means.

[Preferred embodiment of problem solving means]
According to one preferable aspect of the present invention, in the configuration of the above first to fourth aspects, the front wheel is a steered wheel steered by a driver's steering operation, and the rear wheel is a non-steered wheel or as necessary. The wheel is steered in a smaller angle range than the front wheel (preferred aspect 1).

  According to another preferred aspect of the present invention, the degree of approach of the braking / driving force by the abnormality processing means in the configuration of the first to fourth aspects described above is determined when the abnormality occurs in the braking / driving force control means. It is configured to be variably set according to the magnitude of the braking / driving force difference (preferred aspect 2).

  According to another preferred aspect of the present invention, the braking / driving force control means is not capable of generating a normal braking / driving force due to an abnormality in the braking / driving force control means. It is configured to be abnormal (Preferred Aspect 3).

  According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 3, the braking / driving force control means has an abnormality in which the braking / driving force generating means cannot generate normal braking / driving force. In some cases, the braking / driving force of the braking / driving force generating means is set to 0 (preferred aspect 4).

  According to another preferred embodiment of the present invention, the braking / driving force generating means is configured to include an electric motor as an electric braking / driving force generating means. (Preferred embodiment 5).

  According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 5, the electric motor is configured to generate a braking force by a regenerative action (preferred embodiment 6).

  According to another preferred aspect of the present invention, in the configuration of the preferred aspect 5 or 6, the braking / driving force generating means is a friction type braking force generating means for independently controlling the braking forces of the four wheels. (Preferred embodiment 7).

  According to another preferred aspect of the present invention, in the configuration of claim 3, the front wheel kingpin offset is configured to be a positive offset (preferred aspect 8).

  The present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing one embodiment of a traveling control apparatus according to the present invention applied to an in-wheel motor type four-wheel independent braking / driving vehicle.

  In FIG. 1, 10FL and 10FR respectively indicate left and right front wheels, and 10RL and 10RR respectively indicate left and right rear wheels. Motor generators 12FL and 12FR, which are in-wheel motors, are incorporated in the left and right front wheels 10FL and 10FR, respectively. The left and right front wheels 10FL and 10FR are driven by the motor generators 12FL and 12FR, and the motor generators 12FL and 12FR are It is controlled by the electronic controller 14 for driving force control. The motor generators 12FL and 12FR also function as left and right front wheel generators, respectively, and the function as a regenerative generator (regenerative braking) is also controlled by the driving force control electronic control unit 14.

  Similarly, motor generators 12RL and 12RR, which are in-wheel motors, are incorporated in the left and right rear wheels 10RL and 10RR, respectively. The left and right front wheels 10RL and 10RR are driven by the motor generators 12RL and 12RR, and the motor generator 12RL and 12RR are also controlled by the electronic controller 14 for driving force control. The motor generators 12RL and 12RR also function as left and right rear wheel generators, respectively, and the function as a regenerative generator is also controlled by the driving force control electronic control unit 14.

  Although not shown in detail in FIG. 1, the electronic controller 14 for controlling the driving force includes a microcomputer and a driving circuit. The microcomputer includes, for example, a central processing unit (CPU), a read only memory (ROM), and the like. It may have a general configuration including a random access memory (RAM) and an input / output port device, which are connected to each other by a bidirectional common bus. Further, during normal running, electric power charged in a battery not shown in FIG. 1 is supplied to the motor generators 12FL to 12RR through the drive circuit, and during deceleration braking of the vehicle, regenerative braking by the motor generators 12FL to 12RR is performed. The generated electric power is charged into the battery via the drive circuit, and therefore the motor generators 12FL to 12RR function as braking / driving force generating means incorporated in the wheels.

  The left and right front wheels 10FL and 10FR, which are steered wheels, are steered via tie rods 20L and 20R by a rack and pinion type power steering device 18 that is driven in response to steering of the steering wheel 16 by the driver. The left and right rear wheels 10RL and 10RR are non-steering wheels and are not steered even if a steering operation is performed by the driver.

  FIG. 2 is a longitudinal sectional view of the right front wheel 10FR along the lateral direction of the vehicle. As shown in FIG. 2, the right front wheel 10 </ b> FR is connected to the vehicle body 26 by a suspension arm 22 and a suspension strut 24. The suspension arm 22 is pivotally attached to the vehicle body 26 by a joint 28 at an inner end, and is pivotally attached to a wheel support member 32 by a joint 30 at an outer end. The suspension strut 24 is pivotally attached to the vehicle body 26 by a joint 34 at the upper end, and is rigidly connected to the wheel support member 32 at the lower end. The motor generator 12FR is supported by the wheel support member 32, and rotates the wheel 36 of the right front wheel 10FR around the rotation axis 38 relative to the wheel support member 32.

  The joints 30 and 34 define a kingpin shaft 40 of the right front wheel 10FR, and the right front wheel 10FR is steered by being rotated around the kingpin shaft 40 by the power steering device 18. In particular, in the illustrated embodiment, the kingpin shaft 40 intersects the road surface 42 on the inboard side of the vehicle with respect to the ground contact point P of the right front wheel 10FR, and therefore the kingpin offset KO is a positive offset. is not. Although not shown in the drawing, the left front wheel 10FL is configured similarly to the right front wheel 10FR.

  As shown in FIG. 3 for the right front wheel 10FR, the motor generator (12FR) may be mounted on the vehicle body 26, and the front wheel (10FR) may be rotationally driven by the motor generator via the drive shaft 44. In this case, the distance IK between the wheel rotation center plane 46 and the kingpin shaft 40 at the height position of the wheel rotation axis 38 is not zero but set to a positive value on the inboard side of the vehicle.

  The friction braking force of the left and right front wheels 10FL, 10FR and the left and right rear wheels 10RL, 10RR is controlled by controlling the braking pressure of the corresponding wheel cylinders 52FL, 52FR, 52RL, 52RR by the hydraulic circuit 50 of the friction braking device 48. The Although not shown in the drawing, the hydraulic circuit 18 includes a reservoir, an oil pump, various valve devices, etc., and the braking pressure of each wheel cylinder is normally determined by the amount of depression of the brake pedal 54 and depression of the brake pedal 54 by the driver. The brake pedal is controlled by the driver by controlling the oil pump and various valve devices by the braking force control electronic control device 58 as necessary. Control is performed regardless of the amount of stepping 54.

  Although not shown in detail in FIG. 1, the braking force control electronic control unit 58 is also composed of a microcomputer and a drive circuit. The microcomputer includes, for example, a central processing unit (CPU), a read only memory (ROM), and the like. It may have a general configuration including a random access memory (RAM) and an input / output port device, which are connected to each other by a bidirectional common bus.

  The driving force control electronic control device 14 includes a signal indicating an accelerator opening φ as an accelerator pedal depression amount and a shift position (SP) not shown in the figure operated by the driver from the accelerator opening sensor 60. A signal indicating the position Ps of the shift lever not shown in the figure operated by the driver is input from the sensor 62, and exchanges signals with the braking force control electronic control unit 58 as necessary. .

  The braking force control electronic control unit 58 includes a signal indicating the master cylinder pressure Pm from the pressure sensor 64 and a corresponding wheel braking pressure (wheel cylinder pressure) Pi (i = fl, fr, rl, and so on) from the pressure sensors 66FL to 66RR. rr) is input. The braking force control electronic control unit 58 controls the regenerative braking force or braking pressure Pi of each wheel according to the master cylinder pressure Pm detected by the pressure sensor 64 in the normal state, and the braking pressure of each wheel is mutually adjusted as necessary. To control independently.

  In particular, the braking force control electronic control unit 58 calculates the target braking force Fbti (i = fl, fr, rl, rr) of each wheel in accordance with the master cylinder pressure Pm, and the target braking force Fbti is set to the motor generator 12FL. When the regenerative braking force is less than or equal to 12RR, the wheels are braked only by regenerative braking of the motor generators 12FL to 12RR, and when the target braking force Fbti exceeds the maximum regenerative braking force of the motor generators 12FL to 12RR, respectively, The wheels are braked by the maximum regenerative braking force of the generators 12FL to 12RR, and the insufficient braking force is generated by controlling the braking pressure Pi by the friction braking device 48.

  Although not shown in the drawing as a flowchart, the electronic controller 14 for controlling the driving force controls the target driving torque Twti (i = fl, fr, rl, rr) of each wheel based on the accelerator opening φ and the shift position Ps. And the target driving current Iti (i = fl, fr, rl, rr) for the motor generators 12FL to 12RR is calculated based on the target driving torque Twti, and the motor generators 12FL to 12RR are calculated based on the target driving current Iti. By controlling the drive current that is energized, the drive force of each wheel is controlled so that the drive torque Twi of each wheel becomes the target drive torque Twti.

  Further, the driving force control electronic control unit 14 determines whether or not an abnormality has occurred in the motor generators 12FL to 12RR in accordance with the flowchart shown in FIG. 4, and an abnormality has occurred in any of the motor generators 12FL to 12RR. When this occurs, the supply of control current to the motor generators 12FL to 12RR of the wheel is stopped to reduce the braking / driving force of the wheel to 0, and the braking / driving force of the wheel on the opposite side to the abnormal wheel is gradually reduced to 0. The abnormal process of bringing the braking force closer to the braking / driving force of the abnormal wheel is reduced, thereby suppressing the deflection of the vehicle due to the braking / driving force difference between the left and right wheels.

  In particular, when an abnormality occurs in any of the motor generators 12FL to 12RR, the driving force control electronic control unit 14 determines whether the abnormal wheel is a front wheel or a rear wheel, and the abnormal wheel is a front wheel. In some cases, the degree of approach of the braking / driving force due to the abnormal process is made higher than when the abnormal wheel is the rear wheel, so that when the abnormal wheel is the front wheel or the rear wheel, The degree of approach when the braking / driving force of a wheel is brought close to the braking / driving force of an abnormal wheel is optimally controlled.

  The calculation of the target braking force Fbti of each wheel based on the driver's braking operation and the calculation of the target driving torque Tdti of each wheel based on the driver's driving operation do not form the gist of the present invention, and the target braking force Fbti and The target drive torque Tdti may be calculated in any manner known in the art. The determination as to whether or not an abnormality has occurred in the motor generators 12FL to 12RR may also be made in any manner known in the art.

  Next, the braking / driving force control at the time of abnormality in the illustrated embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 4 is started when the driving force control electronic control device 14 is activated, and is repeatedly executed at predetermined time intervals until an ignition switch (not shown) is turned off. Is done.

  First, in step 10, a signal indicating the accelerator opening φ detected by the accelerator opening sensor 60 is read, and in step 20, it is determined that an abnormality has already occurred in the motor generator. If a negative determination is made, the process proceeds to step 40. If an affirmative determination is made, in step 30, the abnormal wheel and the wheel on the opposite side to the abnormal wheel are determined. After the state where the control current is not supplied is maintained, the process returns to Step 10.

  In step 40, it is determined whether or not an abnormality has occurred in the motor generators 12FL to 12RR of any of the wheels. If a negative determination is made, the process returns to step 10 and if an affirmative determination is made. In step 50, after the control current is not supplied to the motor generator of the wheel, the process proceeds to step 60.

  In step 60, it is determined whether the wheel in which the abnormality has occurred in the motor generator is the front wheel. If a negative determination is made, the process proceeds to step 90. If an affirmative determination is made, the process proceeds to step 70. move on.

  In step 70, for example, the control current reduction time T1 is calculated from a map not shown in the figure so that the braking / driving force of the front wheel on the opposite side to the abnormal wheel becomes larger as the magnitude of the braking / driving force becomes larger. In this case, the control current for the motor generator of the front wheel on the opposite side to the abnormal wheel is gradually reduced to 0 over time T1, and finally the flow returns to step 10 after the energization is stopped.

  Similarly, in step 90, for example, the control current reduction time T2 is calculated from a map not shown in the figure so that the braking / driving force of the rear wheel on the opposite side to the abnormal wheel becomes larger as the magnitude of the braking / driving force increases. In step 100, the control current for the motor generator of the rear wheel opposite to the left and right sides of the abnormal wheel is gradually reduced to 0 over time T2, so that the current is finally stopped and then step 10 is performed. Return to.

  Note that the ratio of the T1 time to the magnitude of the braking / driving force of the opposite left and right wheels is smaller than the ratio of the T2 time to the magnitude of the braking / driving force of the opposite left and right wheels, and the opposite wheel when an abnormality occurs in the front wheel. The degree of reduction of the control current for the motor generator is greater than the degree of reduction of the control current for the motor generator of the opposite wheel when an abnormality occurs in the rear wheel.

  In the illustrated embodiment, if an abnormality occurs in one of the motor generators 12FL or 12FR of the left and right front wheels and the motor generator does not generate braking / driving force due to the stop of energization, the braking of the left and right front wheels is controlled. The yaw moment Mwf resulting from the driving force difference acts on the vehicle. Similarly, if an abnormality occurs in one of the motor generators 12RL or 12RR of the left and right rear wheels and the motor generator does not generate braking / driving force due to the stop of energization, the difference in braking / driving force between the left and right rear wheels is generated. The resulting yaw moment Mwr acts on the vehicle.

  Also, since the kingpin offset KO of the left and right front wheels is a positive offset, assuming that the braking / driving force of the left and right front wheels is F, a rotational moment of F × KO acts around the kingpin shaft 40 on the left and right front wheels, and the electric power generation of the left and right front wheels When the machines 12FL and 12FR are normal, the rotational moments of these left and right front wheels are balanced, and the left and right front wheels are not steered by the rotational moment.

  However, if an abnormality occurs in one of the motor generators 12FL or 12FR on the left and right front wheels, and the motor generator does not generate braking / driving force due to the stop of energization, no rotational moment acts on the abnormal wheels. At the same time, since a rotational moment acts on the wheel on the opposite side to the abnormal wheel, the wheel on the opposite side to the abnormal wheel is steered by the rotational moment, and the abnormal wheel is turned through the power steering device 18. Are also steered in the same turning direction. Since the steering direction of the left and right front wheels thus steered is the same as the direction of deflection of the vehicle by the yaw moment Mwf, if an abnormality occurs in one of the motor generators of the left and right front wheels, the vehicle will have a yaw moment Mwf. In addition, the yaw moment Msf due to the steering of the left and right front wheels acts, and therefore, when an abnormality occurs in one motor generator of the left and right front wheels, an abnormality occurs in one motor generator of the left and right rear wheels. It occurs earlier and more greatly than the case.

  According to the illustrated embodiment, it is determined in step 40 whether or not an abnormality has occurred in the motor generators 12FL to 12RR of any wheel, and an abnormality has occurred in the motor generator of any wheel. When it is determined, in step 50, the supply of control current to the wheel is stopped, and in step 60, it is determined whether or not the wheel in which the motor generator has failed is a front wheel.

  When it is determined that the wheel in which the abnormality has occurred in the motor generator is the front wheel, the control current for the front wheel on the side opposite to the abnormal wheel is gradually reduced to 0 in steps 70 and 80 over time T1. When it is finally determined that the energization is stopped and the wheel in which the abnormality has occurred in the motor generator is the rear wheel, in steps 90 and 100, the front wheel on the opposite side to the abnormal wheel over the time T2 is taken. By gradually reducing the control current to 0 to 0, the energization is finally stopped.

  In this case, looking at the difference in braking / driving force of the same magnitude, the time T1 is smaller than the time T2, and the degree of reduction of the control current for the opposite wheel when an abnormality occurs in the front wheel is the same as when the abnormality occurs in the rear wheel. Since the degree of reduction of the control current for the opposite wheel is larger, when the abnormality occurs in one of the motor generators of the left and right front wheels, the degree of approach when bringing the braking / driving force of the normal wheel closer to the braking / driving force of the abnormal wheel is adjusted to the rear wheel. This can be made higher than when an abnormality occurs in one of the left and right rear motor generators.

  Therefore, according to the illustrated embodiment, one of the left and right front wheels is compared with the case where the reduction degree of the control current is the same regardless of whether the wheel in which the abnormality has occurred in the motor generator is the front wheel or the rear wheel. When an abnormality occurs in one of the motor generators, the deflection of the vehicle is effectively suppressed without delay, and when an abnormality occurs in one of the motor generators on the left and right rear wheels, the braking / driving force of the normal wheels is quickly increased excessively. Prevents the vehicle from approaching to the braking / driving force, thereby properly and reliably suppressing vehicle deflection in both cases where the motor generator has an abnormality in the front and rear wheels. For example, as indicated by a one-dot chain line and a two-dot chain line in FIG. 6, the amount of deviation in the course of the vehicle can be reduced within an allowable limit.

  In particular, according to the illustrated embodiment, the control current reduction times T1 and T2 are opposite to those of the abnormal wheel in both cases where the wheel in which the abnormality occurred in the motor generator is the front wheel and the rear wheel. As the magnitude of the braking / driving force of the wheel on the side, and therefore the magnitude of the braking / driving force difference between the left and right wheels, is calculated to be smaller, the higher the possibility that the deflection of the vehicle suddenly increases, the higher the braking / driving force becomes. The degree of approach can be increased, and the vehicle deflection is appropriately and reliably suppressed as compared with the case where the control current reduction times T1 and T2 are constant regardless of the magnitude of the braking / driving force difference between the left and right wheels. be able to.

  According to the illustrated embodiment, if it is determined in step 40 that an abnormality has occurred in any of the motor generators, in step 50, the control current is not supplied to the wheel. Not only when the abnormality occurring in the machine is an abnormality that generates only a braking / driving force smaller than a normal braking / driving force including 0, but also when an abnormality that generates a braking / driving force larger than the normal braking / driving force In addition, the deflection of the vehicle can be appropriately and surely suppressed, and it is possible to reliably prevent wasteful consumption of electric energy by an abnormal motor generator.

  According to the illustrated embodiment, when there is a wheel that is determined to be abnormal in the motor generator, an affirmative determination is made in step 20, and an abnormal wheel and the abnormal wheel are determined in step 30. Since the state where the control current is not applied to the left and right opposite wheels is maintained, even if the driver performs acceleration or braking operation, the abnormal wheel and the abnormal wheel are between the opposite left and right wheels. Therefore, no braking / driving force difference occurs, and no vehicle deflection due to the braking / driving force difference occurs.

  Even if an abnormality occurs in the motor generator of any wheel, the braking function of the friction braking device 48 is maintained, so that the braking force is insufficient and the driver feels uncomfortable due to this. There is no.

  Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the braking / driving force generating means is a motor generator, but as long as the braking / driving force of each wheel can be controlled independently of each other, the braking / driving force generating means is other than the motor generator. In particular, regenerative braking may be omitted.

  In the above-described embodiment, the motor generator as the braking / driving force generating means is incorporated in the wheel. However, in the traveling control device of the present invention, for example, the motor generator is a vehicle as shown in FIG. The present invention may be applied to a four-wheel independent braking / driving vehicle mounted on the vehicle body 26. In the case of this type of vehicle, an F × IK rotational moment acts on the wheel around the kingpin shaft 40.

  In the above-described embodiment, the control current reduction times T1 and T2 are smaller as the magnitude of the braking / driving force difference between the left and right wheels is larger. However, as long as there is a relationship of T1 <T2, the control current reduction times T1 and T2 may be constant. In general, even if the yaw moment acting on the vehicle is the same, the deflection of the vehicle rapidly increases as the vehicle speed V increases, and the adverse effect of the vehicle deflection increases as the vehicle speed V increases. T2 may be modified so as to be variably set according to the vehicle speed V so as to decrease as the vehicle speed V increases.

  In general, an abnormality that generates a braking / driving force larger than the normal braking / driving force occurs, and the change in the braking / driving force difference between the left and right wheels when the braking / driving force of the wheel is set to 0 is normal. In step 40, an abnormality occurs that generates only a braking / driving force smaller than the driving force, and is more rapid than the change in the braking / driving force difference between the left and right wheels when the braking / driving force of the wheel is set to zero. It is also determined whether or not the abnormality is an abnormality that generates a braking / driving force that is greater than the normal braking / driving force, and if the abnormality is an abnormality that generates a braking / driving force that is greater than the normal braking / driving force, The control current reduction times T1 and T2 may be corrected to be set to a shorter time than when the abnormality is an abnormality in which only a braking / driving force smaller than a normal braking / driving force is generated.

  In the above-described embodiment, the front wheels are steered wheels that are steered by a driver's steering operation, and the rear wheels are non-steered wheels. The present invention may be applied to a four-wheel steering type vehicle that is steered within a predetermined angle range smaller than the front wheels.

  In the above-described embodiments, the suspension is a strut suspension. However, the travel control device of the present invention is applicable to a vehicle having a suspension other than a strut suspension such as a double wishbone suspension or a multilink suspension. May be applied.

  Further, in the above embodiment, the front wheel kingpin offset is a positive offset, but the traveling control apparatus of the present invention may be applied to a vehicle in which the front wheel kingpin offset is a negative offset, in which case The steering direction of the left and right front wheels, which are steered when an abnormality occurs in one motor generator of the front wheels and the energization is stopped, is the deflection direction of the vehicle due to the yaw moment Mwf resulting from the braking / driving force difference between the left and right front wheels Since the direction is reverse, the degree of approach of the braking / driving force when an abnormality occurs in the braking / driving force generating means of the front wheel that is the steered wheel is the degree of braking / driving force when the abnormality occurs in the braking / driving force generating means of the rear wheel. It is set lower than the degree of approach.

It is a schematic block diagram which shows one Example of the traveling control apparatus by this invention applied to the in-wheel motor-type four-wheel independent braking / driving vehicle. It is a longitudinal cross-sectional view in alignment with the vehicle horizontal direction of the right front wheel in an Example. It is a longitudinal cross-sectional view along the vehicle lateral direction of the right front wheel of the four-wheel independent braking / driving vehicle in which the motor generator is mounted on the vehicle body. It is a flowchart which shows the braking / driving force control routine at the time of abnormality generation in an Example. It is a graph which shows the relationship between the magnitude | size of the braking / driving force of the front wheel on the left and right opposite side, the control current reduction time T1 of the front wheel, and the control current reduction time T2 of the rear wheel. In the conventional vehicle, when an abnormality occurs in one braking / driving force generating means of the front wheel (solid line), when an abnormality occurs in one braking / driving force generating means of the rear wheel (broken line), the present invention is applied. When an abnormality occurs in one braking / driving force generating means of the front wheel (one-dot chain line), and when an abnormality occurs in one braking / driving force generating means of the rear wheel (two-dot chain line), It is a graph which shows the example of the change of a course deviation amount.

Explanation of symbols

12FL to 12RR motor generator 14 electronic control device for driving force control 18 power steering device 48 friction braking device 54 brake pedal 58 electronic control device for braking force control 60 accelerator opening sensor 62 shift position sensor 64, 66FL to 66RR pressure sensor

Claims (4)

  A braking / driving force control means capable of independently controlling the braking / driving forces of four wheels, a means for detecting an abnormality in the braking / driving force control means of any one wheel, and a braking / driving force control means of any one wheel. An abnormality processing means for bringing the braking / driving force of the wheel on the opposite side of the abnormal wheel close to the braking / driving force of the abnormal wheel when an abnormality is detected; The degree of approach of the braking / driving force by the abnormality processing means when abnormality occurs is higher than the degree of approach of the braking / driving force by the abnormality processing means when abnormality occurs in the braking / driving force control means of the rear wheel. A traveling control device for a four-wheel independent drive vehicle characterized by the above.   2. The traveling control apparatus for a four-wheel independent braking / driving vehicle according to claim 1, wherein the braking / driving force control means includes braking / driving force generating means provided for each wheel for braking / driving the corresponding wheel.   The travel control device for a four-wheel independent braking / driving vehicle according to claim 2, wherein the braking / driving force generating means is incorporated in a wheel, and a kingpin offset of a front wheel is not zero. The braking / driving force generating means is mounted on the vehicle body, and the distance between the rotation center plane of the front wheel and the kingpin shaft at the height position of the rotation axis of the front wheel when viewed in the vehicle longitudinal direction is not zero. The traveling control apparatus for a four-wheel independent braking / driving vehicle according to claim 2,

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