A triple power reaching law-enhanced exponential power sliding mode framework for precise high-speed tracking in dielectric elastomer actuators

This paper proposes a novel control framework that integrates Exponential Power Nonsingular Terminal Sliding Mode Control (EPNTSMC) with an Improved Triple Power Reaching Law (ITPRL) to achieve high-speed, high-precision trajectory tracking of dielectric elastomer actuators (DEAs). Unlike existing DEA controllers, the exponential velocity-error sliding manifold guarantees rapid nonsingular finite-time convergence, while the ITPRL adaptively accelerates the reaching phase through fractional power terms, simultaneously boosting convergence speed and mitigating chattering. A rigorous Lyapunov analysis confirms finite-time stability and closed-loop robustness. Experimental validation on a custom DEA testbed demonstrates substantial performance gains, with tracking errors reduced by up to 91.1% (maximum) and 89.8% (RMS) compared to its open-loop performance, while maintaining minimal phase lag across a broad frequency range. The proposed EPNTSMC–ITPRL strategy thus delivers a scalable, high-performance solution to the long-standing control challenges of DEAs, enabling precise and robust operation for advanced soft robotics and biomedical applications.