Modeling and Control of a Six-Axis Precision Motion Control Stage

This work presents a newly developed six-axis magnetic suspension stage for precision motion control. The designed travel volume is 4/spl times/4/spl times/2 mm in translation and 1/spl deg//spl times/1/spl deg//spl times/2/spl deg/ in rotation. A dynamic model of the feedback linearized and uncoupled stage is developed for the purpose of motion control. Model parameter variations are demonstrated through closed-loop system identification. In motion control, a parameter variation model is proposed in conjunction with a reduced order observer to compensate the joined effect of disturbance, modeling error, and cross coupling. Experimental results in terms of positioning stability, motion resolution, rotational motion control, model regulation, large travel multiaxis contouring, and disturbance rejection are shown. Uniform positioning stability and invariant dynamic response within the designed travel volume are illustrated.