Vehicle suspension control with wheel and body demand force phase determination

• US 5,570,289 A
• Filed: 03/27/1995
• Issued: 10/29/1996
• Est. Priority Date: 03/27/1995
• Status: Expired due to Term

• Current Assignee: BWI Company Limited SA (Shougang Corporation)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Arwine, Joan B., Stacey, Scott A.
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/410,794
• Time in Patent Office: 582 Days
• Field of Search: 364/424.05, 280/840, 280/707, 180/41
• US Class Current: 701/37
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 2202/41 Fluid actuator
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/206 Body oscillation speed; Body vibration frequency
• CPC Class Codes: B60G 2400/208 of wheel rotation
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/41 Steering angle
• CPC Class Codes: B60G 2400/91 Frequency
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/08 Failure or malfunction detecting means
• CPC Class Codes: B60G 2600/182 Active control means
• CPC Class Codes: B60G 2600/60 Signal noise suppression; Electronic filtering means
• CPC Class Codes: B60G 2600/76 Digital systems

Abstract

A suspension system control according to the steps of: measuring a set of parameters indicative of motion of a body of the vehicle and of motion of wheels of the vehicle; determining a body demand force responsive to the measured parameters; determining a set of wheel demand forces responsive to the measured parameters; for each wheel of the vehicle: comparing the body demand force and the corresponding wheel demand force to determine whether the body demand force and the corresponding wheel demand forces are in phase; if the body demand force and the corresponding wheel demand force are in phase, determining a damper command responsive to the greater of the body and corresponding wheel demand force; if the body demand force and the corresponding wheel demand force are out of phase, determining the damper command responsive to the sum of the body demand force and the corresponding wheel demand force; and applying the determined damper command to a controllable variable force damper, wherein wheel vertical velocity occurring after a suspension event is minimized without sacrifice to passenger isolation from the suspension event.

Claims

1. A suspension system control method according to the steps of:

measuring a set of parameters indicative of motion of a body of a vehicle and of motion of wheels of the vehicle;

determining a body demand force responsive to the measured parameters;

determining a set of wheel demand forces responsive to the measured parameters;

for each wheel of the vehicle;

comparing the body demand force and the corresponding wheel demand force to determine whether the body demand force and the corresponding wheel demand force are in phase;

if the body demand force and the corresponding wheel demand force are in phase, determining a damper command responsive to the greater of the body and corresponding wheel demand force;

if the body demand force and the corresponding wheel demand force are out of phase, determining the damper command responsive to the sum of the body demand force and the corresponding wheel demand force; and

applying the determined damper command to a controllable variable force damper.

2. A suspension system control method for use in a vehicle, comprising the steps of:

determining a body command responsive motion of a body of the vehicle;

determining a wheel command responsive to motion of a wheel of the vehicle;

comparing the body and wheel commands to determine if the body and wheel commands are in phase;

if the body and wheel commands are in phase, determining which of the body and wheel demands is greater and determining a damper command responsive to the greater of the body and wheel commands;

if the body and wheel commands are not in phase, determining a damper command responsive to a sum of the body and wheel commands;

applying the damper command to a damper mounted between the wheel and the body.

3. A method comprising the steps of:

receiving a plurality of sensor signals;

determining, responsive to at least one of the plurality of sensor signals, a relative velocity between a wheel and a vehicle body;

determining, responsive to at least one of the plurality of sensor signals, a heave velocity, a roll velocity and a pitch velocity of the vehicle body;

determining, responsive to the relative velocity, a wheel demand force;

determining, responsive to the heave, roll and pitch velocities, a body demand force;

comparing the wheel and body demand forces to determine if the wheel and body demand forces are in phase;

if the wheel and body demand forces are in phase, determining an actuator command responsive to a greater of the wheel and body demand forces;

if the wheel and body demand forces are not in phase, determining the actuator command responsive to a sum of the wheel and body demand forces.

4. The method of claim 3, also comprising the step of applying the actuator command to a controllable variable force damper mounted between the wheel and body.

5. A suspension control system for use in a vehicle including a suspended vehicle body, four un-suspended vehicle wheels, four variable force actuators mounted between the vehicle body and wheels, one of the variable force actuators at each comer of the vehicle, and a set of sensors providing sensor signals indicative of motion of the vehicle body and of the vehicle wheels, the suspension control system comprising a microcomputer control unit including:

means for receiving the sensor signals;

means, responsive to the sensor signals indicative of motion of the vehicle body, for determining a body demand force; and

for each wheel (i) means responsive to the sensor signals indicative of motion of the vehicle wheel, for determining a wheel demand force, (ii) means for comparing the determined wheel demand force to the body demand force to determine if the wheel and body demand forces are in phase, (iii) if the wheel and body demand forces are in phase, determining a damper command responsive to a greater of the wheel and body demand forces, and (iv) if the wheel and body demand forces are not in phase, determining a damper command responsive to a sum of the wheel and body demand forces.