ELECTRICALLY DRIVEN VEHICLE

• US 20080001558A1
• Filed: 06/19/2007
• Published: 01/03/2008
• Est. Priority Date: 06/28/2006
• Status: Active Grant

• Current Assignee: Hitachi Industrial Products, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Kikuchi, Akira, Sugawara, Naoshi, Shimada, Keizo, Ikimi, Takashi
• Granted Patent: US 7,583,036 B2
• Time in Patent Office: Days
• US Class Current: 318/5
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 2240/24 Steering angle
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/045 Improving turning performance
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/04 by means of separate power sources
• CPC Class Codes: B62D 11/24 Endless track steering specially adapted for vehicles having both steerable wheels and endless track
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

In an electrically driven vehicle having a controller, the vehicle has a steering angle sensor for outputting a detected value of a steering angle of the vehicle, the controller includes a first torque order pattern along which a torque order for a first electric motor is determined and a second torque order pattern along which a torque order for a second electric motor is determined, and the first and second torque order pattern are modified on the basis of the detected value of the steering angle so that the torque order determined along the second torque order pattern is greater than the torque order determined along the first torque order pattern under the identical velocity when the vehicle turns to the left, and the torque order determined along the first torque order pattern is greater than the torque order determined along the second torque order pattern under the identical velocity when the vehicle turns to the right.

Claims

1. An electrically driven vehicle comprising,

a first electric motor for driving a left side wheel,

a second electric motor for driving a right side wheel, and

an electric motor controller for controlling the first and second electric motors,

wherein the vehicle further comprises a steering angle sensor for measuring a steering angle of the vehicle to output a detected value of the steering angle,

the electric motor controller includes a first torque order pattern for determining a torque order for the first electric motor and a second torque order pattern for determining a torque order for the second electric motor,

the first torque order pattern and the second torque order pattern are modified in accordance with the detected value of the steering angle so that the torque order determined along the second torque order pattern is greater than the torque order determined along the first torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the first torque order pattern is greater than the torque order determined along the second torque order pattern under the identical velocity when the vehicle turns to the right.

2. An electrically driven vehicle comprising,

a first electric motor for driving a left side wheel,

a second electric motor for driving a right side wheel, and

an electric motor controller for controlling the first and second electric motors,

wherein the vehicle further comprises,

a first velocity sensor for measuring a velocity of the first electric motor to output a first detected value of velocity, and

a second velocity sensor for measuring a velocity of the second electric motor to output a second detected value of velocity,

the electric motor controller includes a first torque order pattern for determining a torque order for the first electric motor and a second torque order pattern for determining a torque order for the second electric motor,

the electric motor controller modifies the first torque order pattern and the second torque order pattern in accordance with the first detected value of velocity and the second detected value of velocity when at least one of a difference between the first detected value of velocity and the second detected value of velocity and a ratio therebetween is within a predetermined range so that the torque order determined along the second torque order pattern is greater than the torque order determined along the first torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the first torque order pattern is greater than the torque order determined along the second torque order pattern under the identical velocity when the vehicle turns to the right, and when the at least one of the difference between the first detected value of velocity and the second detected value of velocity and the ratio therebetween is at the outside of the predetermined range, the first torque order pattern and the second torque order pattern are prevented from being further modified.

3. An electrically driven vehicle comprising,

a first electric motor for driving a left side wheel,

a second electric motor for driving a right side wheel, and

an electric motor controller for controlling the first and second electric motors,

wherein the vehicle further comprises a steering angle sensor for measuring a steering angle of the vehicle to output a detected value of the steering angle,

a first velocity sensor for measuring a velocity of the first electric motor to output a first detected value of velocity, and

a second velocity sensor for measuring a velocity of the second electric motor to output a second detected value of velocity,

the electric motor controller includes a first torque order pattern for determining a torque order for the first electric motor and a second torque order pattern for determining a torque order for the second electric motor,

the first torque order pattern and the second torque order pattern are modified in accordance with the detected value of the steering angle, the first detected value of velocity and the second detected value of velocity so that the torque order determined along the second torque order pattern is greater than the torque order determined along the first torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the first torque order pattern is greater than the torque order determined along the second torque order pattern under the identical velocity when the vehicle turns to the right.

4. An electrically driven vehicle comprising,

electric motors for at least one of driving and braking left and right wheels respectively, and

an electric motor controller for controlling the electric motors,

wherein the electric motor controller includes a left side torque order pattern as a function of a velocity of the wheel arranged at a left side of the vehicle and a right side torque order pattern as a function of a velocity of the wheel arranged at a right side of the vehicle,

the electric motor for at least one of driving and braking the wheel arranged at the left side of the vehicle is controlled in accordance with a torque order determined along the left side torque order pattern,

the electric motor for at least one of driving and braking the wheel arranged at the right side of the vehicle is controlled in accordance with a torque order determined along the right side torque order pattern,

the electric motor controller further includes a steering angle sensor for measuring a steering angle of the vehicle,

the left side torque order pattern and the right side torque order pattern are modified in accordance with a detected value of the steering angle output by the steering angle sensor so that the torque order determined along the right side torque order pattern is greater than the torque order determined along the left side torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the left side torque order pattern is greater than the torque order determined along the right side torque order pattern under the identical velocity when the vehicle turns to the right.

5. An electrically driven vehicle comprising,

electric motors for at least one of driving and braking left and right wheels respectively, and

an electric motor controller for controlling the electric motors,

wherein the electric motor controller includes a left side torque order pattern as a function of a velocity of the wheel arranged at a left side of the vehicle and a right side torque order pattern as a function of a velocity of the wheel arranged at a right side of the vehicle,

the electric motor for at least one of driving and braking the wheel arranged at the left side of the vehicle is controlled in accordance with a torque order determined along the left side torque order pattern,

the electric motor for at least one of driving and braking the wheel arranged at the right side of the vehicle is controlled in accordance with a torque order determined along the right side torque order pattern,

the electric motor controller further includes a left side velocity sensor for measuring a velocity of the electric motor for at least one of driving and braking the wheel arranged at the left side of the vehicle and a right side velocity sensor for measuring a velocity of the electric motor for at least one of driving and braking the wheel arranged at the right side of the vehicle,

the left side torque order pattern and the right side torque order pattern are modified in accordance with a measured value of the velocity output by the left side velocity sensor and a measured value of the velocity output by the right side velocity sensor when at least one of a difference between the measured value of the velocity output by the left side velocity sensor and the measured value of the velocity output by the right side velocity sensor and a ratio therebetween is within a predetermined range so that the torque order determined along the right side torque order pattern is greater than the torque order determined along the left side torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the left side torque order pattern is greater than the torque order determined along the right side torque order pattern under the identical velocity when the vehicle turns to the right, and when the at least one of the difference between the measured value of the velocity output by the left side velocity sensor and the measured value of the velocity output by the right side velocity sensor and the ratio therebetween is at the outside of the predetermined range, the left side torque order pattern and the right side torque order pattern are prevented from being further modified.

6. An electrically driven vehicle comprising,

electric motors for at least one of driving and braking left and right wheels respectively, and

an electric motor controller for controlling the electric motors,

wherein the electric motor controller includes a left side torque order pattern as a function of a velocity of the wheel arranged at a left side of the vehicle and a right side torque order pattern as a function of a velocity of the wheel arranged at a right side of the vehicle,

the electric motor for at least one of driving and braking the wheel arranged at the left side of the vehicle is controlled in accordance with a torque order determined along the left side torque order pattern,

the electric motor for at least one of driving and braking the wheel arranged at the right side of the vehicle is controlled in accordance with a torque order determined along the right side torque order pattern,

the electric motor controller further includes a steering angle sensor for measuring a steering angle of the vehicle, a left side velocity sensor for measuring a velocity of the electric motor for at least one of driving and braking the wheel arranged at the left side of the vehicle and a right side velocity sensor for measuring a velocity of the electric motor for at least one of driving and braking the wheel arranged at the right side of the vehicle,

the first torque order pattern and the second torque order pattern are modified in accordance with the detected value of the steering angle, the measured value of the velocity output by the left side velocity sensor and the measured value of the velocity output by the right side velocity sensor so that the torque order determined along the right side torque order pattern is greater than the torque order determined along the left side torque order pattern under the identical velocity when the vehicle turns to the left, and

the torque order determined along the left side torque order pattern is greater than the torque order determined along the right side torque order pattern under the identical velocity when the vehicle turns to the right.

7. An electrically driven vehicle comprising,

a pair of first and second wheels to be arranged at respective sides opposite to each other in a direction perpendicular to a proceeding direction of the vehicle so that when the vehicle turns with a steering angle, one of the first and second wheels is arranged at a relatively radially inner side on the turn of the vehicle and the other one of the first and second wheels is arranged at a relatively radially outer side on the turn of the vehicle,

first and second electric motors for generating actual torques for driving rotationally the wheels respectively on respective rotational axes, and

a controller for controlling the first and second electric motors,

wherein the controller determines desired output torques of the respective first and second electric motors on the basis of required one of acceleration and deceleration of the vehicle, and modifies the desired output torques in accordance with at least one of desired steering angle and actual steering angle so that the desired output torque in absolute value for the one of the first and second wheels is made smaller than the desired output torque in absolute value for the other one of the first and second wheels while a difference in absolute value between the desired output torque for the one of the first and second wheels and the desired output torque for the other one of the first and second wheels increases in accordance with an increase in absolute value of the at least one of desired steering angle and actual steering angle, and the first and second electric motors generate the respective actual torques in accordance with the respective desired output torques modified.

8. The electrically driven vehicle according to claim 7, wherein the controller further modifies the desired output torques in accordance with respective rotational speeds of respective ones of the wheels so that the desired output torques in absolute value decrease in accordance with increases in absolute value of the respective rotational speeds of the respective ones of the wheels.

9. The electrically driven vehicle according to claim 7, wherein the controller modifies at least one of the desired output torques in accordance with an average value between rotational speeds of respective ones of the wheels so that a difference in absolute value between the desired output torques decrease in accordance with an increase in absolute value of the average value.

10. An electrically driven vehicle comprising,

a pair of first and second wheels to be arranged at respective sides opposite to each other in a direction perpendicular to a proceeding direction of the vehicle so that when the vehicle turns, one of the first and second wheels is arranged at a relatively radially inner side on the turn of the vehicle and the other one of the first and second wheels is arranged at a relatively radially outer side on the turn of the vehicle,

first and second electric motors for generating actual torques for driving rotationally the wheels respectively on respective rotational axes, and

a controller for controlling the first and second electric motors,

wherein the controller determines desired output torques of the respective first and second electric motors on the basis of required one of acceleration and deceleration of the vehicle, and modifies the desired output torques in accordance with at least one of a speed difference in absolute value between rotational speeds of respective ones of the wheels and a ratio of relatively greater one in absolute value of the rotational speeds of the respective ones of the wheels with respect to relatively smaller one in absolute value thereof so that a torque difference in absolute value between the desired output torque for the one of the first and second wheels and the desired output torque for the other one of the first and second wheels increases in accordance with an increase in absolute value of the at least one of the speed difference and the ratio while the torque difference in absolute value is limited within a predetermined degree, and the first and second electric motors generate the respective actual torques in accordance with the respective desired output torques modified.

11. An electrically driven vehicle comprising,

a pair of first and second wheels to be arranged at respective sides opposite to each other in a direction perpendicular to a proceeding direction of the vehicle so that when the vehicle turns, one of the first and second wheels is arranged at a relatively radially inner side on the turn of the vehicle and the other one of the first and second wheels is arranged at a relatively radially outer side on the turn of the vehicle,

first and second electric motors for generating actual torques for driving rotationally the wheels respectively on respective rotational axes, and

a controller for controlling the first and second electric motors,

wherein the controller determines desired output torques of the respective first and second electric motors on the basis of required one of acceleration and deceleration of the vehicle, and modifies the desired output torques in accordance with respective rotational speeds of respective ones of the wheels so that the desired output torques in absolute value decrease in accordance with increases in absolute value of the respective rotational speeds of the respective ones of the wheels, and the first and second electric motors generate the respective actual torques in accordance with the respective desired output torques modified.

12. An electrically driven vehicle comprising,

a pair of first and second wheels to be arranged at respective sides opposite to each other in a direction perpendicular to a proceeding direction of the vehicle so that when the vehicle turns, one of the first and second wheels is arranged at a relatively radially inner side on the turn of the vehicle and the other one of the first and second wheels is arranged at a relatively radially outer side on the turn of the vehicle,

first and second electric motors for generating actual torques for driving rotationally the wheels respectively on respective rotational axes, and

a controller for controlling the first and second electric motors,

wherein the controller determines desired output torques of the respective first and second electric motors on the basis of required one of acceleration and deceleration of the vehicle, and modifies at least one of the desired output torques in accordance with an average value between rotational speeds of respective ones of the wheels so that a difference in absolute value between the desired output torques decrease in accordance with an increase in absolute value of the average value, and the first and second electric motors generate the respective actual torques in accordance with the respective desired output torques modified.