Physic-based and control-oriented modelling based robust control for soft dielectric elastomer actuator

Dielectric elastomer actuators (DEA) have attracted increasing attention in the field of soft robotics for use in generating soft and compliant motions. However, owing to their strong viscoelasticity, nonlinearity, and uncertainty, it is often difficult to gain high-precision tracking control. Here, a physic-based and control-oriented modeling based robust control is proposed to alleviate this difficulty in tracking. First, a conical DEA is designed, along with a physics-based and control-oriented model used to describe its dynamic behaviors. After this, a two-step identification method is proposed to obtain the model's parameters. Using the model, a robust control approach is then developed to achieve satisfactory control performance-even when tracking multi-frequency and wide-range reference trajectory under uncertain conditions. Its stability is then analyzed and proofed. Finally, we conduct experiments to demonstrate and test the effectiveness of the actuator.