Electronic power assisted steering system and method

• US 6,647,330 B1
• Filed: 04/30/2002
• Issued: 11/11/2003
• Est. Priority Date: 04/30/2002
• Status: Expired due to Term

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Gluch, Mark W.
• Primary Examiner(s): Cuchlinski, Jr., William A
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US10/136,795
• Publication Number:
  US 20030204294A1
• Time in Patent Office: 560 Days
• Field of Search: 701/41, 701/42, 180/412, 180/413, 180/416, 180/421, 180/422, 180/280, 280/735
• US Class Current: 701/41
• CPC Class Codes: B62D 5/0457 characterised by control features of the drive means as such
• CPC Class Codes: B62D 5/0475 Controlling other elements
• CPC Class Codes: H02J 3/003 Load forecast, e.g. methods or systems for forecasting future load demand
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: Y04S 10/50 Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

Abstract

An electronic power assisted steering system and method wherein vehicle operating parameters, such as steering rack rate and position, are employed to predict future current requirements of the power assisted steering system, and adjust vehicle operating parameters, such as engine and alternator systems, to assure the appropriate power supply to the power assisted steering system without voltage peaks or sags.

Claims

1. A method for controlling a vehicle electric power supply that provides power to an electronic power assisted steering system, the method comprising the steps of:

determining a position of a steering member;

determining a rate of movement and a direction of movement for the steering member;

determining if the steering member is moving toward an electrical power peak;

determining the vehicle speed;

calculating the derivative of the rate of movement for the steering member;

calculating a first future point in time at which a particular electrical power increase is needed for the electronic power assisted steering system, if the steering member is moving toward the electrical power peak;

calculating the amplitude of the particular power increase at the first future point in time, if the steering member is moving toward the electrical power peak; and

adjusting the electric power supply to produce a power output that includes the particular power increase, at the first future point in time, if the steering member is moving toward the electrical power peak.

2. The method of claim 1 further comprising the steps of:

determining if the steering member is moving away from the electrical power peak;

calculating a second future point in time at which a particular electrical power decrease is needed for the electronic power assisted steering system, if the steering member is moving away from the electrical power peak;

calculating the amplitude of the particular power decrease at the second future point in time, if the steering member is moving away from an electrical power peak; and

adjusting the electrical power supply to produce a power output that includes the particular power decrease, at the second future point in time, if the steering member is moving away from the electrical power peak.

3. The method of claim 2 further including the steps of:

controlling operation of a vehicle engine; and

adjusting the engine to cause a decrease in the power output of the power supply, if the steering member is moving away from the electrical power peak.

4. The method of claim 2 wherein the step of calculating the amplitude of the particular power decrease at the second future point in time includes reading an alternator field current.

5. The method of claim 2 wherein the step of calculating the amplitude of the particular power decrease at the second future point in time includes reading a battery voltage.

6. The method of claim 2 wherein the step of calculating the amplitude of the particular power decrease at the second future point in time includes reading a battery current of the electronic power assisted steering system.

7. The method of claim 2 wherein the step of calculating the amplitude of the particular power decrease at the second future point in time includes the steps of:

reading an alternator field current;

reading a battery voltage; and

reading a battery current of the electronic power assisted steering system.

8. The method of claim 1 further including the steps of:

controlling the operation of a vehicle engine; and

adjusting the engine to cause an increase in the power output of the power supply, if the steering member is moving toward the electrical power peak.

9. The method of claim 1 wherein the step of calculating the amplitude of the particular power increase at the first future point in time includes reading an alternator field current.

10. The method of claim 1 wherein the step of calculating the amplitude of the particular power increase at the first future point in time includes reading a battery voltage.

11. The method of claim 1 wherein the step of calculating the amplitude of the particular power increase at the first future point in time includes reading a battery current of the electronic power assisted steering system.

12. The method of claim 1 wherein the step of determining a position of a steering member includes determining the position of a steering rack;

and wherein the step of determining a rate of movement and a direction of movement for the steering member includes determining the rate of movement and the direction of movement of the steering rack.

13. A method for controlling a vehicle electric power supply that provides power to an electronic power assisted steering system, the method comprising the steps of:

determining a position of a steering member;

determining a rate of movement and a direction of movement for the steering member;

determining if the steering member is moving toward an electrical power peak;

determining the vehicle speed;

calculating the derivative of the rate of movement for the steering member;

calculating a first future point in time at which a particular electrical power increase is needed for the electronic power assisted steering system, if the steering member is moving toward the electrical power peak;

calculating the amplitude of the particular power increase at the first future point in time, if the steering member is moving toward the electrical power peak;

adjusting the electric power supply to produce a power output that includes the particular power increase, at the first future point in time, if the steering member is moving toward the electrical power peak;

determining if the steering member is moving away from the electrical power peak;

calculating a second future point in time at which a particular electrical power decrease is needed for the electronic power assisted steering system, if the steering member is moving away from the electrical power peak;

calculating the amplitude of the particular power decrease at the second future point in time, if the steering member is moving away from an electrical power peak; and

adjusting the electrical power supply to produce a power output that includes the particular power decrease, at the second future point in time, if the steering member is moving away from the electrical power peak.

14. The method of claim 13 wherein the step of calculating the amplitude of the particular power increase at the first future point in time includes the steps of:

reading an alternator field current;

reading a battery voltage; and

reading a battery current of the electronic power assisted steering system.

15. The method of claim 13 wherein the step of calculating the amplitude of the particular power decrease at the second future point in time includes the steps of:

reading an alternator field current;

reading a battery voltage; and

reading a battery current of the electronic power assisted steering system.

16. The method of claim 13 further including the steps of:

controlling the operation of a vehicle engine; and

adjusting the engine to cause an increase in the power output of the power supply, if the steering member is moving toward the electrical power peak.

17. An apparatus for a vehicle having an engine and an alternator, the apparatus comprising:

a steering system including a steering wheel, a steering assembly operatively engaging the steering wheel and adapted to engage a vehicle wheel assembly, an electric motor operatively engaging the steering assembly, and a steering motor controller operatively engaging the electric motor;

a steering sensor capable of determining at least one of a position of the steering assembly and a rate of movement of the steering assembly;

a first determinor for determining if the steering assembly is moving toward an increase in a power requirement;

a second determinor for determining an amplitude of the increase in the power requirement;

a third determiner for determining a timing of the increase; and

a current regulator adapted for adjusting the power output of the alternator in response to the amplitude and timing of the increase.

18. The apparatus of claim 17 wherein the steering assembly includes a rack and a pinion, and wherein the steering sensor operatively engages the rack.

19. The apparatus of claim 17 further including an engine controller operatively engaging the steering motor controller, and a vehicle speed sensor operatively engaging the engine controller.

20. The apparatus of claim 17 wherein the third determiner includes a calculator adapted for calculating a derivative of the rate of movement of the steering assembly.