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: To determine the relative position of movable portions of an assembly, a first magnetic device is coupled to a first portion of the assembly. The first magnetic device has a sensing surface with a number of magnetic poles that provide a magnetization state transition location. An absolute position sensor with a two-state output is coupled to the assembly adjacent the first magnetic device. The output state changes when a magnetization state transition of the first magnetic device moves past the absolute position sensor. A second magnetic device is coupled to the assembly. The second magnetic device creates a cyclically-varying magnetic field proximate its sensing surface. An incremental position sensor is coupled to the assembly adjacent the second magnetic device, and has an output that varies continuously relative to magnetic field angle over at least a portion of one cycle of the cyclically-varying magnetic field of the second magnetic device.

Abstract: To determine the relative position of movable portions of an assembly, a first magnetic device is coupled to a first portion of the assembly. The first magnetic device has a sensing surface with a number of magnetic poles that provide a magnetization state transition location. An absolute position sensor with a two-state output is coupled to the assembly adjacent the first magnetic device. The output state changes when a magnetization state transition of the first magnetic device moves past the absolute position sensor. A second magnetic device is coupled to the assembly. The second magnetic device creates a cyclically-varying magnetic field proximate its sensing surface. An incremental position sensor is coupled to the assembly adjacent the second magnetic device, and has an output that varies continuously relative to magnetic field angle over at least a portion of one cycle of the cyclically-varying magnetic field of the second magnetic device.

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.