Fluid active suspension apparatus and operation control method therefor

A method of controlling operation of a fluid active suspension apparatus whose suspending characteristic is actively changed in accordance with supply and discharge of an operating fluid to and from a fluid actuator, comprising the steps of:

• (a) detecting a relative displacement between sprung and unsprung sides;
• (b) obtaining a relative displacement velocity between the sprung and unsprung sides based on the detected relative displacement;
• (c) generating control information having a phase close to that of a sprung vertical acceleration, by subjecting the relative displacement velocity to a phase compensation process;
• and
• (d) carrying out supply/discharge control of a compressible fluid as said operating fluid, in accordance with the control information.

A method of controlling operation of a fluid active suspension apparatus whose suspending characteristic is actively changed in accordance with supply and discharge of an operating fluid to and from a fluid actuator, comprising the steps of:

• presetting a plurality of supply/discharge control patterns;
• detecting a parameter related to a sprung vertical motion;
• measuring a number of times supply/discharge control has been executed;
• selecting a required supply/discharge control pattern from among the supply/discharge control patterns in accordance with the magnitude of the detected sprung vertical motion-related parameter and the measured number of times supply/discharge control has been executed;
• and
• carrying out supply/discharge control of a compressible fluid as the operating fluid, in accordance with the selected supply/discharge control pattern.

A fluid active suspension apparatus comprising:

• fluid actuators arranged between sprung and unsprung sides of a vehicle and associated with front- and rear-wheel sides of the vehicle, respectively;
• a supply source for supplying a compressible fluid;
• a supply valve arranged in a supply pipe connecting the fluid actuators and the supply source;
• a discharge valve arranged in a discharge pipe connected to the fluid actuators;
• detecting means for detecting a sprung vertical motion-related parameter and generating an output representing the detected parameter;
• and
• control means including memory means storing a plurality of supply/discharge control patterns, the control means selecting a pattern suited to the output of the detecting means, from among said plurality of supply/discharge control patterns, and controlling open/close operation of the supply valve and the discharge valve in accordance with the selected supply/discharge control pattern, to thereby control supply and discharge of the compressible fluid to and from the fluid actuators.

A fluid active suspension apparatus comprising:

• a fluid actuator arranged between sprung and unsprung sides of a vehicle;
• a supply source for supplying a compressible fluid;
• a supply valve arranged in a supply pipe connecting the fluid actuator and the supply source;
• a discharge valve arranged in a discharge pipe connected to the fluid actuator;
• detecting means for detecting a sprung vertical acceleration and generating an output representing the detected sprung vertical acceleration;
• and
• control means for controlling open/close operation of the supply valve and the discharge valve, at timing such that a sprung vertical velocity is canceled out by a change in pressure of the compressible fluid in the fluid actuator, in accordance with the output of the detecting means, to thereby control supply and discharge of the compressible fluid to and from the fluid actuator.