SYSTEM AND METHOD FOR VEHICLE DYNAMICS CONTROL IN ELECTRIC DRIVE VEHICLES

• US 20110238251A1
• Filed: 03/24/2011
• Published: 09/29/2011
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Wrightspeed, Inc.
• Original Assignee: Wrightspeed, Inc.
• Inventors: Cash, Ryan, Wright, Ian
• Granted Patent: US 8,718,897 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 7/0007 the motor being electric
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 15/32 Control or regulation of multiple-unit electrically-propelled vehicles
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2240/465 Slip
• CPC Class Codes: B60L 3/102 of individual wheels
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2720/26 Wheel slip
• CPC Class Codes: B60W 30/18172 Preventing, or responsive to skidding of wheels
• CPC Class Codes: B60W 50/087 where the control system corrects or modifies a request from the driver
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

Embodiments of the invention are directed toward a geared traction drive system configured to drive a wheel of a vehicle, comprising: a driveshaft for transmitting power to the wheel; an electric drive motor for driving the driveshaft, the electric drive motor configured to receive signals from a vehicle dynamic control system to command a required speed; a gear reduction component for reducing the speed of the motor by a predetermined factor to a lower speed suitable for driving the wheel; and a drive electronics component that works with the electric drive motor to drive the wheel to the speed commanded by the vehicle dynamic control system.

Claims

1. A geared traction drive system configured to drive a wheel of a vehicle, comprising:

a driveshaft for transmitting power to the wheel;

an electric drive motor for driving the driveshaft, the electric drive motor configured to receive signals from a vehicle dynamic control system to command a required speed;

a gear reduction component for reducing the speed of the motor by a predetermined factor to a lower speed suitable for driving the wheel; and

a drive electronics component that works with the electric drive motor to drive the wheel to the speed commanded by the vehicle dynamic control system.

2. The system of claim 1, wherein the vehicle dynamic control system includes a non-transitory computer readable medium having computer executable program code embodied thereon, the computer executable program code configured to receive sensor inputs, calculate a required wheel speed, and send appropriate signals to the electric drive motor to command the required wheel speed.

3. The system of claim 2, wherein the program code is further configured to use the received sensor inputs to calculate friction coefficients, slip rates and angles, velocity vectors and resultant wheel motor speed, torque commands, vehicle mass, location of center of gravity, and changes in cornering coefficients.

4. The system of claim 1, wherein the electric drive motor delivers torque to the wheel with precise vehicle dynamics control including stability, regenerative braking, traction control, rollover prevention, torque limiting, and current limiting.

5. The system of claim 1, wherein the gear reduction component is configured to increase the torque of the wheel by the predetermined factor.

6. The system of claim 1, wherein the gear reduction component comprises a multiple speed gearbox.

7. The system of claim 1, wherein the vehicle dynamic control system includes a main control processor comprising a dedicated general purpose microcomputer with flash memory main storage, RAM, and communications ports to interface to various driver controls.

8. The system of claim 1, wherein the vehicle dynamic control system receives inputs from the driver controls and a velocity vector sensor, which measures the speed and direction of the vehicle over the roads.

9. The system of claim 8, wherein the velocity vector sensor comprises a module including a CCD camera chip and lens, MEMS accelerometers, and a DSP for image processing.

10. The system of claim 8, wherein the driver controls include a steering angle sensor for measuring steering position, a brake pressure sensor or brake pedal switch for measuring brake pressure, and an accelerator including a sensor for measuring accelerator position.

11. The system of claim 8, wherein the vehicle dynamic control system uses the inputs received from the velocity vector sensor and the driver controls to calculate a required speed of the wheel and send corresponding signals to the electric drive motor to command the calculated speed.

12. The system of claim 1, wherein the vehicle dynamic control system is configured to calculate effective tire circumference, tire pressure, tire slip rate, and tire slip angle.

13. A computer program product comprising a non-transitory computer readable medium having computer executable program code embodied thereon, the computer executable program code configured to drive a wheel of a vehicle using a geared traction drive system including a driveshaft for transmitting power to the wheel, an electric drive motor for driving the driveshaft, a gear reduction component, and a drive electronics component, by performing the steps of:

receiving sensor inputs from a plurality of sensors;

calculating a required wheel speed; and

sending appropriate signals to the electric drive motor to command the required wheel speed.

14. The computer program product of claim 13, further comprising using the received sensor inputs to calculate friction coefficients, slip rates and angles, velocity vectors and resultant wheel motor speed, torque commands, vehicle mass, location of center of gravity, and changes in cornering coefficients.

15. The computer program product of claim 13, further comprising controlling the electric drive motor to deliver torque to the wheel with precise vehicle dynamics control including stability, regenerative braking, traction control, rollover prevention, torque limiting, and current limiting.

16. The computer program product of claim 13, further comprising controlling the gear reduction component to reduce the speed of the motor by a predetermined factor to a lower speed suitable for driving the wheel.

17. The computer program product of claim 16, further comprising controlling the gear reduction component to increase the torque of the wheel by the same predetermined factor.

18. The computer program product of claim 13, wherein the gear reduction component comprises a multiple speed gearbox.

19. The computer program product of claim 13, wherein the computer program product includes a main control processor comprising a dedicated general purpose microcomputer with flash memory main storage, RAM, and communications ports to interface to various driver controls.

20. The computer program product of claim 13, further comprising receiving inputs from the driver controls and a velocity vector sensor, which measures the speed and direction of the vehicle over the roads.

21. The computer program product of claim 20, wherein the velocity vector sensor comprises a module including a CCD camera chip and lens, MEMS accelerometers, and a DSP for image processing.

22. The computer program product of claim 20, wherein the driver controls include a steering angle sensor for measuring steering position, a brake pressure sensor or brake pedal switch for measuring brake pressure, and an accelerator including a sensor for measuring accelerator position.

23. The computer program product of claim 20, further comprising using the inputs received from the velocity vector sensor and the driver controls to calculate a required speed of the wheel and send corresponding signals to the electric drive motor to command the calculated speed.

24. The computer program product of claim 23, wherein the electric drive motor and drive electronics component operate to drive the wheel to the speed commanded by the vehicle dynamic control system.

25. The computer program product of claim 13, further comprising calculating effective tire circumference, tire pressure, tire slip rate, and tire slip angle.