Design and control of an electromagnetic actuator without mechanical springs

The paper describes a new form of actuator that depends on eddy currents for its operation. Its design with the aid of computational electromagnetics taking account of the external power supply and thermal effects is presented. The variation of the thrust with displacement of the actuator is shown to depend largely on one design parameter. It is shown however that this restriction can be overcome by modulating the exciting voltage as a function of the actuator displacement in real lime, The control is achieved by the use of DSP hardware and software. The need for a mechanical spring is eliminated by the design employing a single conducting tube with two stators.