A Generalized Motion Control Framework of Dielectric Elastomer Actuators: Dynamic Modeling, Sliding-Mode Control and Experimental Evaluation

The continuous electromechanical deformation of dielectric elastomer actuators (DEAs) suffers from rate- dependent viscoelasticity, mechanical vibration and configura- tion dependency, making the generalized dynamic modeling and precise control elusive. In this work, we present a generalized motion control framework for DEAs capable of accommodating different configurations, materials and degrees of freedom (DOFs). First, a generalized, control-enabling dynamic model is developed for DEAs by taking both nonlinear electrome- chanical coupling, mechanical vibration and rate-dependent viscoelasticity into consideration. Further, a state observer is introduced to predict the unobservable viscoelasticity. Then, an Enhanced Exponential Reaching Law based Sliding-Mode Controller (EERLSMC) is proposed to minimize the viscoelas- ticity of DEAs. Its stability is also proved mathematically. The experimental results obtained for different DEAs (four configurations, two materials and multi-DOFs) demonstrate that our dynamic model can precisely describe their complex dynamic responses and the EERLSMC can achieve precise tracking control; verifying the generality and versatility of our motion control framework.