Vehicle suspension control system

• US 5,864,768 A
• Filed: 09/09/1996
• Issued: 01/26/1999
• Est. Priority Date: 09/09/1996
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Bieber, Martin, Mackool, Sam Mike, Rhode, Douglas Scott
• Primary Examiner(s): Chin, Gary
• Application Number:
  US08/709,704
• Time in Patent Office: 869 Days
• Field of Search: 701/37, 701/38, 701/39, 280/707, 280/840, 280/5.506, 280/5.507, 280/5.513
• US Class Current: 701/38
• CPC Class Codes: B60G 17/0182 involving parameter estimation, e.g. observer, Kalman filter
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/122 Summation signal
• CPC Class Codes: B60G 2600/16 Integrating means, i.e. integral control
• CPC Class Codes: B60G 2600/17 Proportional control, i.e. gain control
• CPC Class Codes: B60G 2600/184 Semi-Active control means
• CPC Class Codes: B60G 2600/1874 Modal analysis
• CPC Class Codes: B60G 2600/60 Signal noise suppression; Electronic filtering means
• CPC Class Codes: B60G 2600/70 Computer memory; Data storage, e.g. maps for adaptive control

Abstract

A method and apparatus for controlling continuously variable dampers in a vehicle suspension system is provided. A microcontroller receives sensor signals from the vehicle and generates heave, pitch and roll acceleration signals, heave, pitch and roll actual velocity signals, and heave, pitch and roll velocity level signals based on the received sensor signals. Heave, pitch and roll control signals are then calculated based on the acceleration, actual velocity, and velocity level signals, and the continuously variable dampers are adjusted in accordance with the calculated heave, pitch and roll control signals. A deadband schedule function is provided for adjusting the control signals in accordance with the significance of the particular ride event.

Claims

1. A method for controlling continuously variable dampers in a vehicle suspension system, comprising:

receiving sensor signals from the vehicle;

generating heave, pitch and roll acceleration signals, heave, pitch and roll actual velocity signals, and heave, pitch and roll velocity amplitude level signals based on the received sensor signals;

calculating a heave control signal, a pitch control signal and a roll control signal based on the acceleration, actual velocity and velocity amplitude level signals; and

adjusting the continuously variable dampers in accordance with the calculated heave, pitch and roll control signals.

2. The method of claim 1, wherein the step of receiving sensor signals comprises receiving signals from vertical accelerometers on the vehicle.

3. The method of claim 2, further comprising performing a matrix multiplication on the signals received from the vertical accelerometers to yield heave, pitch and roll acceleration signals, and filtering any low frequency components from the heave, pitch and roll acceleration signals.

4. The method of claim 3, wherein the step of generating heave, pitch and roll actual velocity signals comprises integrating the filtered heave, pitch and roll acceleration signals.

5. The method of claim 1, further comprising multiplying the calculated heave, pitch and roll control signals by a deadband schedule function indicative of the significance of the particular ride event.

6. A vehicle suspension system, comprising:

a plurality of sensors connected to the vehicle;

a plurality of continuously variable dampers connected to the vehicle; and

a controller in electrical communication with the sensors and dampers, said controller being operative to;

receive sensor signals from the sensors;

generate heave, pitch and roll acceleration signals, heave, pitch and roll actual velocity signals, and heave, pitch and roll velocity amplitude level signals based on the received sensor signals;

calculate a heave control signal, a pitch control signal and a roll control signal based on the acceleration, actual velocity and velocity amplitude level signals; and

adjust the continuously variable dampers in accordance with the calculated heave, pitch and roll control signals.

7. The suspension system of claim 6, wherein the controller is further operative to multiply the calculated heave, pitch and roll control signals by a deadband schedule function indicative of the significance of the particular ride event.

8. The suspension system of claim 6, wherein said sensors comprise vertical accelerometers, and the controller is further operative to perform a matrix multiplication on the signals received from the vertical accelerometers to yield heave, pitch and roll acceleration signals, and to filter any low frequency components from the heave, pitch and roll acceleration signals.

9. The suspension system of claim 8, wherein the controller is further operative to integrate the filtered heave, pitch and roll acceleration signals to generate said actual velocity signals.

10. A method for controlling continuously variable dampers in a vehicle suspension system, comprising:

receiving sensor signals from the vehicle;

generating heave, pitch and roll acceleration signals, heave, pitch and roll actual velocity signals, and heave, pitch and roll velocity amplitude level signals based on the received sensor signals;

calculating a heave control signal, a pitch control signal and a roll control signal in accordance with the following formula;

##EQU2## where G_vel is a velocity gain, vel is the actual velocity, rf is a rounding factor, vel_-- level is the velocity amplitude level, G_acc is an acceleration gain, and acc is the acceleration for the respective heave, pitch or roll mode; and

adjusting the continuously variable dampers in accordance with the calculated control signals.