Method and system for controlling automotive suspension system, particularly for controlling suspension characteristics in accordance with road surface conditions

An automotive suspension control system comprising:

• a suspension system suspending road wheels from a vehicle body and having suspension characteristics variable between a first harder suspension characteristics mode and a second softer suspension characteristics mode;
• an actuator selectively operating said suspension system in a selected one of said first harder suspension characteristics mode and said second softer suspension characteristics mode;
• a first sensor means for monitoring a vehicle driving operation leading to changes in vehicle attitude and producing a first sensor signal having a value representative of the magnitude of change in vehicle attitude;
• a second sensor means for monitoring the roughness of the road surface and producing a second sensor signal indicative of the road surface condition;
• and
• a controller deriving a control signal ordering said actuator to operate said suspension system in the selected one of said first and second suspension characteristics modes depending on said first sensor signal value and predetermined control characteristics which defines a schedule of varying the suspension characteristics of said suspension system in relation to vehicle attitude change represented by said first sensor signal value, in such a manner that said suspension system normally operates in said second softer suspension characteristics mode and operates in said first harder suspension characteristics more in response to vehicle attitude changes exceeding a predetermined magnitude, said controller selecting one of a plurality of control characteristics according to the value of said second sensor signal.

In an automotive suspension control system including a suspension system suspending road wheels from a vehicle body and having suspension characteristics variable between a first harder suspension characteristics mode and a second softer suspension characteristics mode, and an actuator associated with said suspension system for operating said suspension system in a selected one of said first harder suspension characteristics mode and said second softer suspension characteristics mode,

• a method for controlling the suspension characteristics comprising the steps of:
• monitoring a preselected first suspension control parameter indicative of vehicle attitude and producing a first signal;
• monitoring roughness of the road surface and producing a second signal indicative of the road surface condition, and
• deriving a control signal for operating said actuator to operate said suspension system in the selected one of said first harder suspension characteristics mode and said second softer suspension characteristics mode depending on said first signal value and according to predetermined control characteristics which define criterion of said first sensor signal value for switching suspension characteristics of said suspension system between said first harder characteristics mode position and said second softer characteristics mode, said control characteristics being selected among a plurality of predetermined control characteristics according to the value of said second sensor signal.

An anti-rolling automotive suspension control system comprising:

• a suspension system suspending road wheels from a vehicle body and having suspension characteristics variable between a first harder suspension characteristics mode and a second softer suspension characteristics mode;
• an actuator selectively operating said suspension system in a selected one of said first harder suspension characteristics mode and said second softer suspension characteristics mode;
• a first sensor monitoring a vehicular rolling magnitude representing parameter and producing a first sensor signal indicative thereof;
• a second sensor monitoring roughness of the road surface and producing a second sensor signal indicative of the road surface condition;
• and
• a controller normally deriving a control signal for operating said actuator to operate said suspension system in said second softer suspension characteristics mode and responsive to said first sensor signal value greater than a threshold value representative of a harder suspension criterion for deriving said control signal to operate said suspension system in said first harder suspension characteristics mode, said controller varying said threshold value according to said second sensor signal value.

An anti-pitching automotive suspension control system comprising:

• a suspension system suspending road wheels from a vehicle body and having suspension characteristics variable between a first harder suspension characteristics mode and a second softer suspension characteristics mode;
• an actuator selectively operating said suspension system in a selected one of said first harder suspension characteristics mode and said second softer suspension characteristics mode;
• a first sensor monitoring a vehicular pitching magnitude representing parameter and producing a first sensor signal indicative thereof;
• a second sensor monitoring roughness of the road surface and producing a second sensor signal indicative of the road surface condition;
• and
• a controller normally deriving a control signal for operating said actuator to operate said suspension system in said second softer suspension characteristics mode and responsive to said first sensor signal value being greater than a threshold value representative of a harder suspension criterion for deriving said control signal to operate said suspension system in said first harder suspension characteristics mode, said controller varying said threshold value according to said second sensor signal value.

An anti-bouncing automotive suspension control system comprising:

• a suspension system suspending road wheels from a vehicle body and having suspension characteristics variable between a first harder suspension characteristics mode and a second softer suspension characteristics mode;
• an actuator selectively operating said suspension system in a selected one of said first harder suspension characteristics mode position and said second softer suspension characteristics mode position;
• a first sensor monitoring a vehicular bouncing magnitude representing parameter and producing a first sensor signal indicative thereof;
• a second sensor monitoring roughness of the road surface and producing a second sensor signal indicative of the road surface condition;
• and
• a controller normally deriving a control signal for operating said actuator to operate said suspension system in said second softer suspension characteristics mode and responsive to said first sensor signal value being greater than a threshold value representative of a harder suspension criterion for deriving said control signal to operate said suspension system in said first harder suspension characteristics mode, said controller varying said threshold value according to said second sensor signal value.