Vehicle-speed control device

Patent metadata

Field	Value
Publication number	US-10870356-B2
Application number	US-201615761159-A
Country	US
Kind code	B2
Filing date	Sep 12, 2016
Priority date	Oct 26, 2015
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

Abstract

A vehicle speed control unit includes feedback control parts, the number of feedback control parts corresponding to the number of multiple motors, generating feedback command torques for the respective motors, on the basis of respective deviations between speed signals from speed sensors detecting revolution speeds of the multiple motors and feedback target vehicle-speed signal reshaped from the inputted target vehicle-speed signal by target vehicle-speed filters; a feedforward control part calculating a feedforward command torque for the vehicle as a whole, on the basis of the inputted target vehicle-speed signal; and a torque distribution part dividing the feedforward command torque into individual feedforward command torques for distribution to the respective motors, wherein the individual feedforward command torques are respectively added to the feedback command torques and, to control the respective motors.

First claim

The invention claimed is:

1. A vehicle speed controller comprising:
a processor configured to:
control multiple motors driving wheels of a vehicle provided with the multiple motors so that a speed of the vehicle follows a vehicle speed indicated by a target vehicle speed signal being input;
generate feedback command torques for feedback controlling each of the multiple motors, based on a respective deviation between a speed signal from a speed sensor detecting a revolution speed of each of the multiple motors and a feedback target vehicle speed signal obtained by passing the inputted target vehicle speed signal through a target vehicle speed filter, to feedback-control the multiple motors;
calculate a feedforward command torque for feedforward controlling the vehicle using a transfer function whose input is the inputted target vehicle speed signal and whose output is the feedforward command torque for the vehicle; and
divide the feedforward command torque into individual feedforward command torques for distribution to the multiple motors,
wherein the transfer function used in calculating the feedforward command torque is a product of a transfer function of the target vehicle speed filter used in generating the feedback command torques multiplied by an inverse model of a transfer function of the vehicle, the transfer function of the vehicle having as an input a summation of forces in a direction of translational motion of the vehicle and having as an output the vehicle speed, and
wherein the processor respectively adds the individual feedforward command torques to the feedback command torques for the multiple motors, to control the multiple motors.

2. The vehicle speed controller of claim 1 , wherein the processor respectively generates feedback command torques for the multiple motors, based on respective deviations between the speed signals and individual feedback target vehicle speed signals for the multiple motors driving the wheels that are corrected from the feedback target vehicle speed signal reshaped from the inputted target vehicle speed signal by the target vehicle speed filter, based on the speed of and a yaw rate of the vehicle, and geometric positional relations of the contact points with the ground of, steering angles of, and sideslip angles of the wheels.

3. The vehicle speed controller of claim 2 , wherein in a case the vehicle includes total four wheels of right and left pairs of front and rear wheels and with the multiple motors for respectively driving the right and left pairs of wheels via differential gears, the processor calculates respective target vehicle speeds for the four wheels and then average the target vehicle speeds for the right and left pairs of wheels as corrected feedback target vehicle speeds for the right and left pairs of wheels.

4. The vehicle speed controller of claim 1 , wherein the feedback control of the multiple motors respectively includes integral controls, and the processor decreases gains of the integral controls with increase of the revolution speeds of the multiple motors and/or increase of a steering angle of the vehicle.

5. The vehicle speed controller of claim 1 , wherein the processor decreases the feedforward command torque, based on a relative speed between the vehicle and an obstacle detected by an obstacle detection sensor detecting a distance to and the obstacle ahead of or behind the vehicle.

6. The vehicle speed controller of claim 5 , wherein the processor decreases the feedforward command torque, based on an inter-vehicle time based on a relative distance or a relative speed between the vehicle and the obstacle detected by the obstacle detection sensor.

7. The vehicle speed controller of claim 1 , wherein a control characteristic of at least one of the feedback controls of the multiple motors has a different control characteristic in at least either one of gain and phase from at least another one of the feedback controls.

8. The vehicle speed controller of claim 7 , wherein among the feedback controls, a feedback control of a motor driving one front wheel or two front wheels of the wheels and a feedback control of a motor driving one rear wheel or two rear wheels of the wheels have different control characteristics from each other.

9. The vehicle speed controller of claim 7 , wherein the different control characteristics are frequency characteristics.

10. The vehicle speed controller of claim 1 , wherein the speed signals from the speed sensors are the speed signals that are respectively filtered by speed signal filters for the multiple motors.

11. The vehicle speed controller of claim 1 , wherein the processor respectively adds the individual feedforward command torques to the feedback command torques, to control the multiple motors according to command torques that are respectively filtered from the added individual feedforward command torques, by torque filters for the multiple motors.

12. The vehicle speed controller of claim 1 , wherein the processor determines, based on an acceleration/deceleration of the vehicle speed indicated by the feedback target vehicle speed signal, a ratio of an individual feedforward command torque to be distributed to a motor driving a front wheel of the wheels or a summation of the individual feedforward command torques to be distributed to motor driving front wheels of the wheels to an individual feedforward command torque to be distributed to a motor driving a rear wheel of the wheels or a summation of the individual feedforward command torques to be distributed to the multiple motors driving rear wheels of the wheels.

13. A vehicle speed control method comprising:
controlling multiple motors driving wheels of a vehicle provided with the multiple motors so that a speed of the vehicle follows a vehicle speed indicated by a target vehicle speed signal being input;
generating feedback command torques for feedback controlling each of the multiple motors, based on a respective deviation between a speed signal from a speed sensor detecting a revolution speed of each of the multiple motors and a feedback target vehicle speed signal obtained by passing the inputted target vehicle speed signal through a target vehicle speed filter, to feedback-control the multiple motors;
calculating a feedforward command torque for feedforward controlling the vehicle using a transfer function whose input is the inputted target vehicle speed signal and whose output is the feedforward command torque for the vehicle;
dividing the feedforward command torque into individual feedforward command torques for distribution to the multiple motors; and
respectively adding the individual feedforward command torques to the feedback command torques for the multiple motors to control the multiple motors,
wherein the transfer function used in calculating the feedforward command torque is a product of a transfer function of the target vehicle speed filter used in generating the feedback command torques multiplied by an inverse model of a transfer function of the vehicle, the transfer function of the vehicle having as an input a summation of forces in a direction of translational motion of the vehicle and whose having as an output the vehicle speed.

Assignees

• Mitsubishi Electric Corp

Inventors

• Yokoyama Kazuto
• Iezawa Masahiro

Classifications

• B60L15/20 Primary

  for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed · CPC title

• B60L2220/42

  with use of more than one motor · CPC title

• Y02T10/64

  Electric machine technologies in electromobility · CPC title

• B60L2240/421

  Speed · CPC title

• B60L15/2045

  for optimising the use of energy · CPC title