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 configuration 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 electromechanical 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 viscoelasticity 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