POWER STEERING SYSTEM AND METHOD OF INFLUENCING THE DAMPING OF A POWER STEERING SYSTEM

• US 20080312794A1
• Filed: 06/18/2008
• Published: 12/18/2008
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: TRW Automotive GmbH (Apollo Global Management, Inc.)
• Original Assignee: TRW Automotive GmbH (Apollo Global Management, Inc.)
• Inventors: ROTH, KLAUS
• Granted Patent: US 8,041,481 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B62D 5/0466 for returning the steering wheel to neutral position
• CPC Class Codes: B62D 5/06 fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

A power steering system is disclosed herein that includes an electronic control unit that determines a set-point value for a damping moment in the power steering system. The system also includes a first sensor connected to the control unit and operable to determine a sign of a steering angle. The sign of the steering angle refers to a clockwise angle from dead center being designated as positive or negative and a counter-clockwise angle from dead center being assigned the other designation. The system also includes a second sensor connected to the control unit and operable to determine the sign of a steering wheel angular velocity. The sign of the steering wheel angular velocity refers to movement of the steering wheel in the clockwise direction being designated as positive or negative and movement in the counter-clockwise direction being assigned the other designation. The control unit can establish the set-point value for the damping moment with a predefined first damping multiplier when the steering angle and the steering wheel angular velocity have the same sign and with a predefined second damping multiplier when the steering angle and the steering wheel angular velocity have different signs.

Claims

1. A power steering system comprising:

an electronic control unit operable to determine a set-point value for a damping moment in the power steering system;

a first sensor connected to the control unit for determining a sign of a steering angle;

a second sensor connected to the control unit for determining a sign of a steering wheel angular velocity; and

wherein

the control unit being operable to establish the set-point value for the damping moment with a predefined first damping multiplier when the steering angle and the steering wheel angular velocity have the same sign and with a predefined second damping multiplier when the steering angle and the steering wheel angular velocity have different signs.

2. The power steering system according to claim 1 wherein the first damping multiplier is smaller than the second damping multiplier.

3. A method of influencing the damping of a power steering system and comprising the steps of:

(a) determining a sign of a steering angle;

(b) determining a sign of a steering wheel angular velocity;

(c) selecting a predefined first damping multiplier if the signs of the steering angle and of the steering wheel angular velocity are the same, or selecting a predefined second damping multiplier if the signs are different; and

(d) establishing a set-point value for a damping moment in the power steering system with the aid of the damping multiplier selected.

4. The method according to claim 3 further comprising the step of:

assigning a lower value to the first damping multiplier than the second damping multiplier.