Design and control of a soft saddle-shaped dielectric elastomer actuator

Here, a soft saddle-shaped dielectric elastomer actuator (SSDEA) is designed and a model-based tracking control approach is developed to achieve its desirable dynamics. In this actuator, a bent polyethylene terephthalate (PET) frame is connected with the dielectric elastomer (DE) driving mechanism. The DE driving mechanism induces PET frame elongation or shortening, which causes the movement of the SSDEA. With the benefit from its modular design, simple structure, and robust mechanical assembly, the SSDEA has the stable and linear driving capability. In order to describe the dynamic behaviors of this actuator, a hybrid modeling method that integrates a data-driven model with a physical model is presented, and a three-step identification method is proposed to obtain the model's parameters. Moreover, a model-based tracking control approach is further developed to achieve satisfactory control performance. Using experiments, the dynamics and control performance of the actuator are demonstrated effectively.