Design and control of long travel range electromagnetically actuated positioning stage with application to precise machining

This paper proposes a long travel range electromagnetically actuated positioning stage with application to micro machining. Specially, a probe with titanium coating is integrated with an electromagnetically actuated and damped positioning stage to perform millimeter range movement. Here, the developed stage replaces traditional piezoelectric actuators for the purpose of lengthening the motion range while minimizing the complexity of the electrical system. Besides that, a laser interferometer is installed and high precision metrology is implemented to improve precision of machining. Next, a robust adaptive sliding-mode controller is proposed to enhance system robustness and to reject environmental disturbance. The controller architecture consists of two major components: 1) sliding mode controller, and 2) robust adaptive law. With the proposed controller, the high precision machining, with the horizontal positioning error (in root-mean-square level) kept within 52nm, can be successfully achieved.