Super-Twisting Sliding Mode Control of Dielectric Elastomer Actuators for Artificial Muscle

Artificial muscles made up of dielectric elastomer have emerged as a promising technology in the field of soft robotics due to their lightweight, high energy density, and ability to undergo large deformations. In order to harness the potential of dielectric elastomers, precise and efficient control strategy is required. This paper presents super-twisting sliding mode control (STSMC) for achieving required actuation. The dynamic equation of motion is obtained using Lagrange method and is further solved using numerical method. In STSMC, the reaching law is modified to include higher-order terms, which leads to less convergence time and better performance. Also, the use of an effective controller leads to suppressing the overshoot which results in preventing instability. The effectiveness of the controller is demonstrated by taking the reference position as single step and multi-step. Further, the performance of the controller in tracking multi-step reference with small time step is also explored. Hence, this paper demonstrates the effectiveness of STSMC in regulating the deformation of dielectric elastomers, enabling them to mimic the required muscle-like motion.