Patent ID: 8116939
Filing Date: 2012-02-14
Classification: B60G

Abstract:
1. A suspension system for a vehicle having front right, front left, rear right and rear left wheels, four sprung portions and four unsprung portions, said suspension system comprising: (a) four displacement force generators provided for the respective four wheels of the vehicle, each of said four displacement force generators including an electromagnetic motor and configured to generate, based on a motor force generated by said electromagnetic motor, a displacement force forcing a corresponding one of the four sprung portions and a corresponding one of the four unsprung portions toward or away from each other; and (b) a control unit configured to control actuation of said electromagnetic motor included in each of said four displacement force generators, so as to control the displacement force that is to be generated by each of said four displacement force generators, wherein said control unit is configured to be capable of executing a plurality of vibration damping controls concurrently with each other, by controlling the displacement force based on a sum of vibration damping components as displacement force components that are to be generated by each of said four displacement force generators in the respective vibration damping controls, so as to damp a composite vibration occurring in a body of the vehicle and containing a plurality of vehicle-body vibrations which are different in kind from each other and which are to be damped by respective vibration damping forces generated by said four displacement force generators in the respective vibration damping controls, wherein said control unit is configured to determine each of the vibration damping components into which a corresponding one of the vibration damping forces is to be divided among said four displacement force generators, wherein said control unit is configured to be capable of executing, as said plurality of vibration damping controls, at least (i) a roll-vibration damping control that is to be executed for damping a roll vibration as one of said plurality of vehicle-body vibrations, (ii) a pitch-vibration damping control that is to be executed for damping a pitch vibration as one of said plurality of vehicle-body vibrations, and (iii) a bounce-vibration damping control that is to be executed for damping a bounce vibration as one of said plurality of vehicle-body vibrations, and wherein said control unit is configured to refrain from executing at least one of said plurality of vibration damping controls in a low vibration intensity situation in which intensities of sprung-portion resonance-frequency vibration components in the respective four sprung portions are lower than a threshold intensity degree, each of said at least one of said plurality of vibration damping controls being to be executed for damping one of said plurality of vehicle-body vibrations that is not required to be damped in said low vibration intensity situation, each of the sprung-portion resonance-frequency vibration components being a component of sprung-portion vibration occurring in a corresponding one of the four sprung portions and having a resonance frequency of the corresponding one of the four sprung portions.