Feedback-cascaded inverse feedforward for viscoelastic creep, hysteresis and cross-coupling compensation in dielectric-elastomer actuated XY stages

In this work, we propose a feedback-cascaded inverse feedback control scheme for viscoelastic creep, hysteresis and cross-coupling compensation in a dielectric-elastomer actuated XY stage. Firstly, we implement two feedback controllers to mitigate the viscoelastic creep nonlinearity and crosscoupling effect of our customized dielectric-elastomer actuated XY (DEA-XY) stage. Next, we, respectively, model the inverse hysteresis nonlinearly of the feedback-compensated systems in X axis and Y axis, and develop the corresponding feedforward controller to compensate for the viscoelastic hysteresis nonlinearity. Experimental results indicate that our developed controllers can reduces the maximum root-mean-square tracking errors (compared to the uncompensated case) by over 90%. We further verify the effectiveness of our proposed control approach to follow different complex planar trajectories, such as Archimedes spiral, circular and butterfly trajectories.