JP6418080B2 - Electric vehicle traveling control device - Google Patents

Description

  The present invention relates to a travel control device for an electric vehicle in which each drive wheel is driven by a respective electric motor.

  In an electric vehicle such as an electric vehicle in which each driving wheel is driven by a respective electric motor, the electric motor for each driving wheel is controlled in a torque control mode during normal driving of the vehicle, and speed control is performed as necessary. It is controlled in the mode. In the torque control mode, the target drive torque of each motor is calculated based on the driver's drive operation amount, and the output of each motor is fed back so that the actual drive torque of the motor becomes the corresponding target drive torque. Be controlled. On the other hand, in the speed control mode, the target rotational speed of the electric motor common to all the drive wheels is calculated based on the driving operation amount of the driver so that the actual rotational speed of the electric motor becomes the target rotational speed. The output of each motor is feedback controlled.

  For example, Patent Document 1 below includes setting means for switching and setting a motor control mode between a torque control mode and a speed control mode, and the motor is controlled in the set mode. An electric vehicle traveling control device is described. According to the electric vehicle described in Patent Document 1, for example, in a situation where the load of the vehicle fluctuates and a situation where the vehicle starts at a high load, the control mode is switched from the torque control mode to the speed control mode. The vehicle can be easily driven at a desired speed.

JP-A-6-14404

[Problems to be Solved by the Invention]
As is well known, when the vehicle turns, the turning radius of the turning inner wheel is smaller than the turning radius of the turning outer wheel, and the moving distance of the turning inner wheel per unit time is smaller than the moving distance of the turning outer wheel. The rotational speed of the inner turning wheel is smaller than that of the outer turning wheel. Therefore, when the control mode is the speed control mode, the actual rotational speed of the motor is smaller than the target rotational speed in the inner turning wheel, and conversely, the actual rotational speed of the motor is smaller than the target rotational speed in the outer turning wheel. Also grows. The deviation between the actual rotational speed and the target rotational speed is constantly generated while the vehicle is turning.

  Therefore, in the turning inner wheel, a command for increasing the rotational speed of the electric motor (command for increasing the driving torque) is continuously output by feedback control of the rotational speed. On the contrary, in the turning outer wheel, a command for reducing the rotation speed of the motor (command for generating a negative driving torque) is continuously output by feedback control of the rotation speed. Since these commands are continuously output while the vehicle is in a turning state, an electric power loss and an increase in the amount of generated heat due to the motor are inevitable in both the turning inner wheel and the turning outer wheel.

The main problem of the present invention is that in an electric vehicle in which the left and right drive wheels are driven by the respective electric motors, the electric motor in the case where the electric vehicle turns in a situation where the left and right electric motors should be controlled in the speed control mode. The power loss and the amount of generated heat are reduced as compared with the conventional case.
[Means for Solving the Problems and Effects of the Invention]

  According to the present invention, when the left and right drive wheels are applied to an electric vehicle driven by the respective electric motors and the preset condition is not satisfied, the actual driving torques of the two electric motors are driven by the driver. When the two motors are feedback-controlled so that the target driving torque is based on the operation amount, and a preset condition is satisfied, the actual rotational speed of the two motors is based on the driving operation amount of the driver. There is provided a travel control device for an electric vehicle that feedback-controls the two electric motors so as to achieve a target rotational speed.

Further, the travel control device, the satisfied preset condition, and, rotational speed of the motor of the turning outer wheel to control the electric motor of the turning outer wheel to be the target rotation speed, the inner wheel of the motor driving dynamic torque controls the motor of the turning inner wheel such that the target driving torque based on the product of the actual drive torque and 1 less positive correction coefficient of the electric motor of the turning outer wheel of the.

According to the above configuration, when a preset condition is satisfied and the electric vehicle is in a turning state, the electric motor of the turning outer wheel is in the speed control mode so that the rotation speed becomes the target rotation speed. Be controlled. Furthermore, the electric motor of the inner turning wheel is controlled so that its driving torque becomes a target driving torque based on the product of the actual driving torque of the electric motor of the outer turning wheel and a positive correction coefficient of 1 or less . Therefore, the rotational speed of the electric motor for the outer turning wheel is controlled so as to reach the target rotational speed without being affected by the rotational speed of the electric motor for the inner turning wheel . Therefore, compared with the case where both the left and right motors are controlled in the speed control mode, the magnitude of the deviation between the actual rotational speed and the target rotational speed of the motor of the outer turning wheel is small. Can be made to substantially coincide with the target rotational speed. Therefore, a situation in which a drive torque increase / decrease command continues to be output does not occur, so that useless energy loss is reduced.

In addition, the drive torque of the motor for the inner ring is controlled so as to be the target drive torque without being influenced by the rotational speed of the motor for the outer ring , and the target drive torque of the motor for the inner ring is the same as that of the motor for the outer ring . This is the target drive torque based on the actual drive torque. Therefore, control of the driving torque of the inner wheel of the motor, so as not to disturb the control of the drive wheel of the turning outer wheel by the mode of the speed control, it is possible to control the drive torque of the electric motor of the turning inner wheel.
Particularly, since the correction coefficient is a positive constant smaller than 1, the target drive torque of the electric motor for the inner turning wheel is a positive torque smaller than the actual driving torque of the electric motor for the outer turning wheel. Therefore, since the yaw moment that promotes turning can be applied to the electric vehicle by the difference in the drive torque of the electric motors of the turning inner and outer wheels, the turning radius of the electric vehicle becomes larger than when the correction coefficient is 1. The fear can be reduced and the turning performance of the electric vehicle can be improved.

Therefore, when a preset condition is satisfied, the control amount of the feedback control is larger than in the conventional case where the left and right motors are controlled in the speed control mode regardless of whether the electric vehicle is in a turning state. The possibility that the situation where the increase / decrease control amount of the drive torque of the electric motor is high can be reduced. Therefore, it is possible to reduce the power loss and the amount of heat generated by the electric motor when the electric vehicle turns, compared to the conventional case.

It is a schematic block diagram which shows the travel control apparatus of the electric vehicle concerning embodiment of this invention applied to the four-wheel drive vehicle of an in-wheel motor type. It is a flowchart which shows the traveling control routine of the electric vehicle in embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing a travel control device 10 for an electric vehicle according to an embodiment of the present invention applied to an in-wheel motor type four-wheel drive vehicle. The travel control device 10 is applied to an electric vehicle 14 having left and right front wheels 12FL and 12FR that are steering wheels and left and right rear wheels 12RL and 12RR that are non-steering wheels. The front wheels 12FL and 12FR are driven by applying driving force independently of each other from in-wheel motors 16FL and 16FR incorporated in the corresponding wheels. Similarly, the left and right rear wheels 12RL and 12RR are driven by applying driving force independently of each other from in-wheel motors 16RL and 16RR incorporated in the corresponding wheels.

  The in-wheel motors 16FL to 16RR may be any motor that can control the drive torque and the rotational speed, and may be, for example, a three-phase brushless AC motor. The in-wheel motors 16FL to 16RR also function as regenerative generators during braking and preferably generate regenerative braking force, but regenerative braking may not be performed.

  The driving force of the in-wheel motors 16FL to 16RR is controlled by the driving force control unit of the electronic control unit 22 based on the accelerator opening Acc detected by the accelerator opening sensor 18, as will be described in detail later. The accelerator opening Acc indicates the amount of depression of the accelerator pedal 20, that is, the amount of driving operation by the driver. The regenerative braking force of the in-wheel motors 16FL to 16RR is controlled by the braking force control unit of the electronic control unit 22 via the driving force control unit.

  During normal traveling of the vehicle 14, although not shown in FIG. 1, the power charged in the battery is supplied to the in-wheel motors 16FL to 16RR via the drive circuit in the drive force control unit. When the vehicle 14 is braked, the power generated by regenerative braking by the in-wheel motors 16FL to 16RR is charged to the battery via the drive circuit.

  A friction braking force is applied to the front wheels 12FL and 12FR and the rear wheels 12RL and 12RR by the friction braking device 24 independently of each other. The friction braking force of the front wheels 12FL and 12FR and the rear wheels 12RL and 12RR is controlled by controlling the pressure in the corresponding wheel cylinders 28FL, 28FR, 28RL and 28RR, that is, the braking pressure, by the hydraulic circuit 26 of the friction braking device 24. Is done. Although not shown in the figure, the hydraulic circuit 26 includes a reservoir, an oil pump, various valve devices, and the like.

  The pressure in the wheel cylinders 28FL to 28RR is controlled in accordance with the pressure in the master cylinder 32 that is driven in response to the depression of the brake pedal 30 by the driver during normal times. Furthermore, the pressure in each wheel cylinder is controlled by the braking force control unit of the electronic control unit 22 as required, so that the oil pump and various valve devices are controlled regardless of the depression amount of the brake pedal 30 by the driver. Be controlled.

  Although not shown in FIG. 1, the electronic control unit 22 includes an integrated control unit that controls these control units in addition to the driving force control unit and the braking force control unit. Each control unit exchanges signals with each other as necessary. As will be described in detail later, the integrated control unit drives the four wheels by controlling the in-wheel motors 16FL to 16RR and the friction braking device 24 so that the driving force of the vehicle matches the driving force required by the driver. Control the power.

  Although not shown in detail in FIG. 1, each control unit of the electronic control unit 22 includes a microcomputer and a drive circuit. Each microcomputer has a general configuration in which a CPU, a ROM, a RAM, and an input / output port device are connected to each other via a bidirectional common bus.

  In addition to the signal indicating the accelerator opening Acc from the accelerator opening sensor 18, the electronic control unit 22 indicates a signal indicating ON / OFF from the brake switch 34, that is, whether or not the driver is performing a braking operation. The signal shown is input. A signal indicating the vehicle speed V is input from the vehicle speed sensor 36 to the electronic control device 22, and a signal indicating the steering angle θ, that is, the rotation angle of the steering shaft (not shown) of the steering device is input from the steering angle sensor 38. . The steering angle sensor 38 detects the steering angle θ with the value when the vehicle is turning left as positive.

  The in-wheel motors 16FL to 16RR include rotation angle sensors (resolvers) 40FL to 40RR and torque sensors 42FL to 42RR, respectively. The electronic control device 22 receives the rotation angle φi and the drive torque Ti (i = fl, fr, rl and rr) of the corresponding in-wheel motors 16FL to 16RR from the rotation angle sensors 40FL to 40RR and the torque sensors 42FL to 42RR, respectively. The signal shown is input.

  In accordance with the flowchart shown in FIG. 2, the electronic control unit 22 controls the driving force, that is, the output of the in-wheel motors 16FL to 16RR in the torque control mode at normal times, and in the speed control mode as necessary. Control.

  In the torque control mode, the target drive torque Tti (i = fl, fr, rl, and rr) of the in-wheel motors 16FL to 16RR is calculated based on the accelerator opening Acc or other parameters. Furthermore, the outputs of the in-wheel motors 16FL to 16RR are feedback-controlled so that the actual drive torque Ti becomes the corresponding target drive torque Tti. On the other hand, in the speed control mode, the target rotational speed Vwt of the in-wheel motors 16FL to 16RR common to the four wheels is calculated based on the accelerator opening Acc, and the actual rotational speed Vwi becomes the target rotational speed Vwt. As described above, the outputs of the in-wheel motors 16FL to 16RR are feedback-controlled. The actual rotation speed Vwi is calculated as a differential value of the rotation angle φi of the in-wheel motor detected by the rotation angle sensors 40FL to 40RR.

  The electronic control unit 22 controls the output of the four-wheel in-wheel motor in the speed control mode by determining whether any of the following speed control execution conditions (E1) to (E4) is satisfied. Determine if it is necessary. Note that reference values such as the reference value V1 in the following speed control execution conditions (E1) to (E4) are positive constants.

(E1) The vehicle speed V is less than the reference value V1, the brake switch 34 is off, and the accelerator opening Acc is less than the reference value Acc1 (execution condition at start).
(E2) The vehicle speed V is less than the reference value V1, the brake switch 34 is on, and the accelerator opening Acc is less than the reference value Acc1 (execution condition during deceleration).
(E3) The deviation (four deviations) between the target driving torque Tti and the corresponding actual driving torque Ti based on the accelerator opening Acc when the accelerator opening Acc is not less than the reference value Acc2 and the brake switch 34 is OFF. At least one of Tti−Ti) is equal to or greater than the reference value ΔT1 (execution condition when climbing).
(E4) The deviation (four deviations) between the accelerator opening Acc is not less than the reference value Acc3, the brake switch 34 is OFF, and the actual driving torque Ti and the corresponding target driving torque Tti based on the accelerator opening Acc At least one of (Ti−Tti) is equal to or greater than the reference value ΔT2 (execution condition during downhill).

  When the electronic control unit 22 determines that none of the speed control execution conditions (E1) to (E4) is satisfied, that is, when the vehicle 14 is traveling normally, the outputs of the four-wheel in-wheel motors 16FL to 16RR are output. Is controlled in the torque control mode. On the other hand, when the electronic control unit 22 determines that any of the speed control execution conditions (E1) to (E4) is satisfied and the vehicle 14 is substantially in a straight traveling state, the in-wheel motor 16FL to The 16RR output is controlled in the speed control mode.

  The electronic control device 22 performs specific control when it is determined that any of the speed control execution conditions (E1) to (E4) is satisfied and the vehicle 14 is in a turning state. That is, the electronic control unit 22 controls the front wheel and rear wheel in-wheel motors on the outer side of the turn in the speed control mode, and controls the front wheel and rear wheel in-wheel motors on the inner side of the turn in the torque control mode.

  Further, the electronic control unit 22 determines whether or not the speed control release condition is satisfied when performing the specific control, and determines that the vehicle 14 is in a turning state because the speed control release condition is not satisfied. If so, the specific control is continued. On the other hand, when it is determined that the speed control release condition is not satisfied and the vehicle 14 is substantially in the straight traveling state, the electronic control unit 22 ends the specific control and the four-wheel in-wheel motor 16FL˜ The 16RR output is controlled in the speed control mode. Furthermore, when it is determined that the speed control release condition is satisfied, the electronic control unit 22 ends the specific control and controls the outputs of the four-wheel in-wheel motors 16FL to 16RR in the torque control mode.

  When the speed control execution conditions (E1) to (E4) are satisfied and specific control is being performed, whether or not the following corresponding speed control release conditions (T1) to (T4) are satisfied, respectively. It is determined whether or not the speed control of the four wheels is unnecessary. Reference values such as the reference value V2 in the following speed control release conditions (T1) to (T4) are also positive constants.

(T1) The vehicle speed V is greater than or equal to a reference value V2 greater than the reference value V1, or the brake switch 34 is on, or the accelerator opening Acc is greater than or equal to a reference value Acc4 greater than the reference value Acc1 (when starting) Exit conditions).
(T2) The vehicle speed V is greater than or equal to a reference value V2 greater than the reference value V1, or the brake switch 34 is OFF, or the accelerator opening Acc is greater than or equal to a reference value Acc4 greater than the reference value Acc1 (during deceleration) Exit conditions).
(T3) A target based on the accelerator opening Acc when the accelerator opening Acc is equal to or less than the reference value Acc5 smaller than the reference value Acc2, or the brake switch 34 is on, or ΔT3 is a reference value smaller than the reference value ΔT1. All of the four deviations (Tti−Ti) between the driving torque Tti and the corresponding actual driving torque Ti are equal to or less than the reference value ΔT3 (end condition when climbing).
(T4) The actual driving torque Ti and the accelerator are determined with the accelerator opening Acc being equal to or smaller than the reference value Acc6 smaller than the reference value Acc3, or the brake switch 34 being on, or ΔT4 being a reference value smaller than the reference value ΔT2. All of the four deviations (Ti−Tti) from the corresponding target drive torque Tti based on the opening Acc are equal to or less than the reference value ΔT4 (end condition when descending slope).

  Next, travel control of the electric vehicle in the embodiment will be described with reference to the flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is repeatedly executed at predetermined time intervals when an ignition switch (not shown) is on. In the following description, the traveling control of the electric vehicle according to the flowchart shown in FIG. 2 is simply referred to as “control”.

  First, in step 10, a signal indicating the accelerator opening Acc from the accelerator opening sensor 18 is read.

  In step 20, it is determined whether or not the flag F is 1, that is, whether or not the four-wheel in-wheel motors 16FL to 16RR are under specific control. When a negative determination is made, control proceeds to step 60, and when an affirmative determination is made, control proceeds to step 30.

  In step 30, it is determined whether or not the conditions corresponding to the speed control execution conditions (E1) to (E4) that are currently satisfied among the speed control cancellation conditions (T1) to (T4) are satisfied. Done. When a negative determination is made, the control proceeds to step 50, and when an affirmative determination is made, after the flag F is reset to 0 in step 40, the control proceeds to step 70.

  In step 50, it is determined whether or not the absolute value of the steering angle θ is equal to or smaller than a reference value θt (positive constant), that is, whether or not the vehicle 14 is substantially in a straight traveling state. Since specific control needs to be continued when a negative determination is made, the control proceeds to step 110, and when an affirmative determination is made, the process proceeds to step 100. Note that the reference value θt may be variably set according to the vehicle speed V or the like, for example, so as to decrease as the vehicle speed V increases.

  In step 60, it is determined whether or not any of the speed control execution conditions (E1) to (E4) is satisfied. When an affirmative determination is made, the control proceeds to step 80, and when a negative determination is made, the control proceeds to step 70.

  In step 70, for example, by referring to a map not shown in the figure, the target driving force Fvt of the vehicle 14 is calculated based on the accelerator opening Acc, and the target driving force Fvt and the driving force distribution ratio of the front and rear wheels are calculated. Based on this, the target drive torque Tti of the four-wheel in-wheel motors 16FL to 16RR is calculated. The target drive torque for the left and right wheels is the same value. Further, the outputs of the four-wheel in-wheel motors 16FL to 16RR are feedback-controlled so that the drive torque Ti of the four-wheel in-wheel motor becomes the corresponding target drive torque Tti (torque control mode).

  In step 80, it is determined whether or not the absolute value of the steering angle θ is larger than a reference value θc (a positive constant equal to or greater than the reference value θt), that is, whether or not the vehicle 14 is in a turning state. Is called. When an affirmative determination is made, after the flag F is set or maintained at 1 in step 90, the control proceeds to step 110, and when a negative determination is made, the control proceeds to step 100. Note that the reference value θc may also be variably set according to the vehicle speed V or the like so as to decrease as the vehicle speed V increases, for example.

  In step 100, for example, by referring to a map not shown in the figure, the target rotational speed Vwt of the in-wheel motors 16FL to 16RR common to the four wheels is calculated based on the accelerator opening Acc. Further, the outputs of the four-wheel in-wheel motors 16FL to 16RR are feedback-controlled so that the actual rotational speed Vwi of the four-wheel in-wheel motors 16FL to 16RR becomes the target rotational speed Vwt (speed control mode).

  In step 110, as in step 100, the target rotational speed Vwt of the four-wheel in-wheel motors 16FL to 16RR is calculated based on the accelerator opening Acc. Further, the outputs of the in-wheel motors 16FL and 16RL or 16FR and 16RR for the outer front wheel and the outer rear wheel so that the actual rotational speed of the in-wheel motor for the outer front wheel and the outer rear wheel becomes the target rotational speed Vwt. Are feedback controlled (speed control mode).

  In step 120, the actual driving torques Tfo and Tro of the corresponding in-wheel motor are obtained based on the signals from the torque sensors 40FL and 40RL or 40FR and 40RR of the in-wheel motor of the turning outer front wheel and the turning outer rear wheel. The

  In step 130, the target driving torque Tit of the turning inner wheel is calculated as the sum of the driving torques Tfo and Tro. Based on the product Tit · K of the target driving torque Tit and the correction coefficient K (a positive constant of 1 or less) and the driving force distribution ratio of the front and rear wheels, the target driving torque Tift of the in-wheel motor of the turning inner front wheel and the turning inner rear wheel And Tirt are calculated. Further, the output of the in-wheel motor of the turning inner front wheel and the turning inner rear wheel is feedback controlled so that the driving torque of the in-wheel motor of the turning inner front wheel and the turning inner rear wheel becomes the corresponding target driving torques Tift and Tirt, respectively. (Torque control mode).

  Next, the operation of the embodiment will be described by dividing it into situations such as whether or not the four-wheel in-wheel motors 16FL to 16RR need to be controlled in the speed control mode.

(A) When the four-wheel in-wheel motor does not need to be controlled in the speed control mode The four-wheel in-wheel motor does not need to be controlled in the speed control mode. When traveling, that is, when none of the speed control execution conditions (E1) to (E4) is satisfied. In this case, a negative determination is made in steps 20 and 60, respectively, and in step 70, the target drive torque Tti of the four-wheel in-wheel motors 16FL to 16RR is calculated based on the accelerator opening Acc. Further, the outputs of the four-wheel in-wheel motors 16FL to 16RR are feedback-controlled so that the drive torque Ti of the four-wheel in-wheel motor becomes the corresponding target drive torque Tti.

(B) When the four-wheel in-wheel motor needs to be controlled in the speed control mode and the vehicle 14 is not in the turning state, the four-wheel in-wheel motors 16FL to 16RR are controlled in the speed control mode. What is necessary is a case where any of the speed control execution conditions (E1) to (E4) is satisfied, and an affirmative determination is made in step 60. However, since the vehicle 14 is not in a turning state, a negative determination is made in step 80, and in step 100, the target rotational speed Vwt of the in-wheel motors 16FL to 16RR common to the four wheels is calculated based on the accelerator opening Acc. . Further, the outputs of the four-wheel in-wheel motors 16FL to 16RR are feedback-controlled so that the actual rotational speed Vwi of the four-wheel in-wheel motors 16FL to 16RR becomes the target rotational speed Vwt.

(C) When the four-wheel in-wheel motor needs to be controlled in the speed control mode and the vehicle 14 is in a turning state, affirmative determination is made in steps 60 and 80, respectively. Therefore, specific control is executed in steps 110 to 130. That is, in step 110, the target rotational speed Vwt of the four-wheel in-wheel motors 16FL to 16RR is calculated based on the accelerator opening degree Acc. Further, the output of the in-wheel motor for the outer front and rear wheels is feedback-controlled so that the actual rotational speed of the in-wheel motor for the outer front and rear wheels becomes the target rotational speed Vwt.

  Further, in steps 120 and 130, the turning inner front and rear wheels are set so that the driving torque of the in-wheel motor of the turning inner front and rear wheels becomes the target driving torques Tift and Tirt based on the actual driving torques Tfo and Tro of the turning outer front and rear wheels. The output of the in-wheel motor is feedback-controlled.

  Note that when the change amount of the drive torque of the in-wheel motor is large when the control mode is switched between the speed control mode and the torque control mode, the target rotational speed Vwt is set so that the change of the drive torque becomes gentle. Alternatively, the target drive torque Tti may be corrected.

  As can be understood from the above description, when the four-wheel in-wheel motors 16FL to 16RR need to be controlled in the speed control mode, the control (B) is performed in principle. That is, the outputs of the four-wheel in-wheel motors 16FL to 16RR are controlled in the speed control mode.

  However, even when the four-wheel in-wheel motors 16FL to 16RR need to be controlled in the speed control mode, the control (C) is performed when the vehicle 14 is in a turning state. That is, the in-wheel motors of the front and rear wheels on the turning outer side are feedback-controlled in the speed control mode so that their actual rotational speed becomes the target rotational wheel speed Vwt. On the other hand, the in-wheel motors of the turning inner front and rear wheels are feedback-controlled so that their driving torque becomes the target driving torque Tit.

  Therefore, the rotational speed of the in-wheel motor of the outer front and rear wheels is controlled to be the target rotational speed without being influenced by the rotational speed of the in-wheel motor of the inner front and rear wheels. Therefore, compared with the conventional case where the in-wheel motors of both the outer turning wheel and the inner turning wheel are controlled in the speed control mode, the actual rotational speed and the target rotational speed of the in-wheel motor of the front and rear wheels outside the turning are Since the magnitude of the deviation becomes small, the actual rotational speed can be made substantially coincident with the target rotational speed by feedback control. Therefore, a situation in which a drive torque increase / decrease command continues to be output does not occur, so that useless energy loss is reduced.

  Further, the driving torque of the in-wheel motors on the inner front and rear wheels is controlled so as to be the target driving torque without being affected by the rotational speed of the in-wheel motors on the outer front and rear wheels. Further, the target drive torque of the electric motor for the front and rear wheels inside the turn is a target drive torque based on the actual drive torque of the electric motor for the front and rear wheels outside the turn. Therefore, it is possible to control the drive torque of the electric motors of the turning inner front and rear wheels so that the control of the driving torques of the electric motors of the turning inner front and rear wheels does not disturb the control of the outer turning front and rear wheels in the speed control mode.

  Accordingly, when any of the speed control execution conditions (E1) to (E4) is satisfied, all in-wheel motors are controlled in the speed control mode regardless of whether or not the electric vehicle 14 is in a turning state. Compared to the conventional case, the control amount of the feedback control can be reduced, and the situation in which the increase / decrease control amount of the drive torque of the electric motor is high can be prevented from continuing. Therefore, it is possible to reduce the power loss and the amount of heat generated by the in-wheel motor when the electric vehicle turns in a situation where any of the speed control execution conditions is satisfied, as compared with the conventional case.

  In particular, when the correction coefficient K is a positive constant smaller than 1, the sum of the target drive torques Tift and Tirt of the in-wheel motor for the turning inner front and rear wheels is the actual sum of the in-wheel motor for the turning outer front and rear wheels. It becomes smaller than the sum of the drive torques Tfo and Tro. Therefore, since the yaw moment that promotes turning can be applied to the electric vehicle 14 due to the difference in the driving torque of the in-wheel motors of the turning inner and outer wheels, the turning of the vehicle 14 can be compared to when the correction coefficient K is 1. The possibility that the radius is increased can be reduced, and the turning performance of the vehicle 14 can be improved.

  Further, as compared with the case where the target drive torque of the in-wheel motor of the turning inner front and rear wheels is calculated based on the accelerator opening degree Acc as in step 70, the driving torque of the turning inner front and rear wheels drives the driving of the turning outer front and rear wheels. The possibility that the turning radius of the vehicle becomes large due to the torque being exceeded can be reduced.

  Although the present invention has been described in detail with respect 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. This will be apparent to those skilled in the art.

  For example, in the above-described embodiment, the specific control is performed by feedback control of the in-wheel motors on the outer front and rear wheels in the speed control mode, and the in-wheel motors on the inner and outer wheels on the turn become the target drive torques Tift and Tirt Is feedback controlled. However, the specific control is based on feedback control of the in-wheel motors on the inner front and rear wheels in the speed control mode, and the in-wheel motor on the outer front and rear wheels is based on the actual driving torque of the in-wheel motor on the inner front and rear wheels. Feedback control may be performed so that the target driving torque is obtained. In this case, it is preferable that the target drive torque of the in-wheel motors on the outer front and rear wheels is calculated so that the sum thereof is equal to or greater than the sum of the actual drive torques of the in-wheel motors on the front and rear wheels.

  Further, in the above-described embodiment, the in-wheel motors 16FL to 16RR apply driving forces to the front wheels 12FL and 12FR and the rear wheels 12RL and 12RR independently of each other. However, the traveling control device of the present invention may be applied to a vehicle in which the front two wheels or the rear two wheels are driving wheels driven by driven wheels or other driving means.

  In the above-described embodiment, whether or not the driver performs a braking operation in the speed control execution conditions (E1) to (E4) and the speed control release conditions (T1) to (T4) is determined by whether the brake switch 34 is on. It is determined by whether or not there is. However, this determination may be performed, for example, by determining whether or not the pressure in the master cylinder 32 is equal to or higher than a reference value.

  In the above-described embodiment, in the torque control mode, the target driving torque for the front and rear wheels is calculated to be different from each other based on the driving force distribution ratio of the front and rear wheels. Further, the target drive torque of the turning front and rear wheels in the specific control is also calculated to be different from each other based on the driving force distribution ratio of the front and rear wheels. However, the target drive torques of the front and rear wheels may be the same.

  Furthermore, as in the above-mentioned Patent Document 1, setting means for switching the motor control mode between the torque control mode and the speed control mode may be provided. In that case, the fact that the control mode is set to the speed control mode may be added to the speed control execution condition, and the fact that the control mode is switched to the torque control mode may be added to the end condition.

DESCRIPTION OF SYMBOLS 10 ... Traveling control apparatus, 12FL-12RR ... Wheel, 14 ... Vehicle, 16FL-16RR ... In-wheel motor, 18 ... Accelerator opening sensor, 22 ... Electronic controller, 36 ... Vehicle speed sensor, 38 ... Steering angle sensor, 40FL- 40RR ... rotation angle sensor, 42FL to 42RR ... torque sensor

Claims (1)

When the left and right drive wheels are applied to an electric vehicle driven by the respective electric motors and the preset condition is not satisfied, the actual driving torque of the two electric motors is a target drive based on the driving operation amount of the driver When the two motors are feedback-controlled to achieve torque and a preset condition is satisfied, the actual rotation speed of the two motors becomes a target rotation speed based on the driving operation amount of the driver. In the travel control device for an electric vehicle that feedback-controls the two electric motors,
The established preset condition is, and, when said electric vehicle is in a turning state, the rotational speed of the motor of the turning outer wheel to control the electric motor of the turning outer wheel to be the target rotation speed, the inner wheel driving the dynamic torque of the motor to control the electric motor of the turning inner wheel such that the target driving torque based on the product of the actual drive torque and 1 less positive correction coefficient of the electric motor of the turning outer wheel of the running of the electric vehicle Control device.

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