Abstract: An active suspension system that interfaces a sprung mass and an unsprung mass is disclosed. The active suspension system includes a suspension comprising one or more actuators capable of exerting a force on the sprung mass to at least partially isolate motion of the sprung mass from motion of the unsprung mass. A user interface allows a user to indicate a desired degree of motion isolation.

Abstract: Active vibration isolation (AVVI) systems are becoming more available in various markets, one such market being vehicle operator seating. Unfamiliarity with the performance of such systems may cause users initial perceptions of system performance to be unfavorable. AVI systems can include a demonstration system capable of providing simulations too users of various types of vibration isolation systems under various input conditions, so that users can be introduced to the system benefits over other systems before using an AVI equipped product in its intended application.

Abstract: Active vibration isolation (AVVI) systems are becoming more available in various markets, one such market being vehicle operator seating. Unfamiliarity with the performance of such systems may cause users initial perceptions of system performance to be unfavorable. AVI systems can include a demonstration system capable of providing simulations too users of various types of vibration isolation systems under various input conditions, so that users can be introduced to the system benefits over other systems before using an AVI equipped product in its intended application.

Abstract: In an active suspension system for actively suspending a plant, a fail-safe system controlled by a failure-detector has a selectively-activated damper coupled to the plant. The damper may be a separate element from the actuator. Under normal circumstances, the damper is deactivated and therefore generates no damping force. However, if the failure detector detects an abnormal state in the system, it activates the damper, thereby causing a damping force that resists motion of the plant.

Abstract: In an active suspension system for actively suspending a plant, a fail-safe system controlled by a failure-detector has a selectively-activated damper coupled to the plant. The damper may be a separate element from the actuator. Under normal circumstances, the damper is deactivated and therefore generates no damping force. However, if the failure detector detects an abnormal state in the system, it activates the damper, thereby causing a damping force that resists motion of the plant.

Abstract: An apparatus has an active suspension including an electromagnetic actuator coupled to a plant in a vehicle. A force bias eliminator is coupled to the plant for causing the actuator to experience a zero-mean load, and a vibration isolation block generates a control signal based on the response of a nominal plant to measured disturbances of the actively suspended plant. A compensation system modifies the control signal in response to a difference between the response of the nominal plant to the control signal and a measured response of the actively-suspended plant to the control signal.

Abstract: A motion control system including components such as an accelerometer for detecting zero force positions and for self-calibrating the motion control system. The motion control system may be implemented in an active seat suspension.

Abstract: An active suspension system includes a relative slow-responding force bias eliminator (such as a pneumatic actuator) and a relatively fast-responding actuator (such as an electromagnetic actuator) that together support a plant (such as a truck seat or vehicle cabin). The system also includes a load-unload detector (which may be a physical or virtual detector) to detect a loading or unloading of the plant. When such a loading or unloading is detected, the system causes the force bias eliminator to respond quickly (e.g., as quick as possible) while controlling the fast-responding actuator so as to preserve the available energy for operating the actuator (e.g., so as to keep the fast-responding actuator from consuming all of its available energy) prior to when the force bias eliminator can respond.

Abstract: A motion control system including components such as an accelerometer for detecting zero force positions and for self-calibrating the motion control system. The motion control system may be implemented in an active seat suspension.

Abstract: An active suspension system includes a relative slow-responding force bias eliminator (such as a pneumatic actuator) and a relatively fast-responding actuator (such as an electromagnetic actuator) that together support a plant (such as a truck seat or vehicle cabin). The system also includes a load-unload detector (which may be a physical or virtual detector) to detect a loading or unloading of the plant. When such a loading or unloading is detected, the system causes the force bias eliminator to respond quickly (e.g., as quick as possible) while controlling the fast-responding actuator so as to preserve the available energy for operating the actuator (e.g., so as to keep the fast-responding actuator from consuming all of its available energy) prior to when the force bias eliminator can respond.

Abstract: A digital absolute position encoder is provided for determining absolute position of a first member with respect to a second member. The absolute position is determined within a resolution cell of L/2.sup.n, where n is an integer and L is a predetermined span. One of the members has a plurality of, m, tracks of binary indicia distributed over the predetermined span, L, where m is an integer less than n. The other member has a plurality of indicia detectors disposed on the second member for detecting the binary indicia. With such an arrangement, an encoder is provided having "a unit-distance code", yet uses less tracks than that used with a conventional Gray code encoder. Further, the encoder has a reduced number of transitions than that required on the track used with a conventional Gray code encoder. Both of these features simplify the design and fabrication for a given encoder resolution.