System integration and control design of a maglev platform for space vibration isolation

Micro-vibration has been a dominant factor impairing the performance of scientific experiments which are expected to be deployed in a micro-gravity environment such as a space laboratory. The micro-vibration has serious impact on the scientific experiments requiring a quasi-static environment. Therefore, we proposed a maglev vibration isolation platform operating in six degrees of freedom (DOF) to fulfill the environmental requirements. In view of the noncontact and large stroke requirement for micro-vibration isolation, an optimization method was utilized to design the actuator. Mathematical models of the actuator's remarkable nonlinearity were established, so that its output can be compensated according to a floater's varying position and a system's performance may be satisfied. Furthermore, aiming to adapt to an energy-limited environment such as space laboratory, an optimum allocation scheme was put forward, considering that the actuator's nonlinearity, accuracy, and minimum energy-consumption can be obtained simultaneously. In view of operating in 6-DOF, methods for nonlinear compensation and system decoupling were discussed, and the necessary controller was also presented. Simulation and experiments validate the system's performance. With a movement range of 10 x 10 x 8 mm and rotations of 200 mrad, the decay ratio of -40 dB/Dec between 1 and 10 Hz was obtained under close-loop control.