Patent ID: 8444123

Claim:
A suspension system for a seat, the suspension system comprising: a linkage; a base coupled to the seat through the linkage; a pneumatic shock absorber providing a resistance level against movement of the seat with respect to the base; a sensor to detect a vibrational frequency associated with an instantaneous position of the seat versus time; an electric motor coupled to the seat to provide a corrective change of height of the seat in opposition to a vibration-induced change in the instantaneous position of the seat as determined by the vibrational frequency detected by the sensor, wherein the electric motor causes the seat to move upward or downward by a determined amplitude and at a determined time producing a compensation movement of the seat with a compensation frequency 180 degrees out of phase with the vibrational frequency detected by the sensor to actively dampen vibrations; and a controller configured to send, in response to the vibrational frequency detected by the sensor, at least one control signal to change the resistance level of the pneumatic shock absorber and to move the seat by the electric motor, wherein the electric motor provides active damping in response to vibrations transmitted from the vehicle traversing the ground and wherein the pneumatic shock absorber provides passive damping in response to the vibrations, wherein as the passive damping is increased by increasing the pressure level, the active damping by decreasing the amplitude of position changes during a time interval.