Adaptive Intelligent Control for Nonlinear Systems Considering Butterfly-Like Hysteresis and Its Application on Dielectric Elastomer Actuated Motion System

Flexible smart material actuators, i.e., dielectric elastomer actuators(DEAs), have shown great potential applications in the fields of flexiblebionic and rehabilitation robotics due to their high response speed and highenergy conversion efficiency. However, the hysteresis nonlinearities of smartmaterial actuators severely degrade the control performance. To this end, aneural network-based adaptive pseudo-inverse control scheme is proposed for aclass of output-constrained nonlinear time-delay systems actuated by flexiblesmart material actuators. The main features are summarized as follows: 1) anew butterfly-like Krasnoselskii-Pokrovskii (BKP) kernel is derived based onthe traditional Krasnoselskii-Pokrovskii (KP) model, then, by performingweighted superposition of BKP kernel, a new BKP model is proposed to describethe butterfly-like hysteretic loop in the flexible smart material actuators;2) a novel pseudo-inverse control scheme is proposed to overcome thebutterfly-like hysteresis, which implies that the hysteresis inverse modelsare not needed, instead, a temporarily hysteretic controller in which theactual control signal is coupled is designed and a mechanism of extracting theactual control signal from the designed temporarily hysteresis controller isdeveloped, then, the butterfly-like hysteresis is effectively mitigated; 3) toour best knowledge, the output-constrained control problem of thebutterfly-like hysteresis nonlinear systems is solved for the first time bydesigning the barrier-Lyapunov function and the proposed hysteresis looppseudo-inverse control scheme; 4) a DEA-based motion control experimentalplatform is established and the performance of control is verified.