Dynamic Modeling and Adaptive Fuzzy Control of Spatial Deformation Pneumatic Leg Actuators With Error Constraints

Abstract

ABSTRACT With the development of soft crawling robots, pneumatic soft actuators (PSAs) with complicated nonplanar structures are increasingly designed due to the capabilities of achieving compound robot movements. However, the current deformation accuracy of complex PSAs is insufficient to satisfy application requirements. Specifically, the dynamic properties of complex PSAs are still ambiguous and PSA deformation control methods remain lacking, which are caused by inherent characteristics, such as strong nonlinearity and hysteresis. To this end, based on self‐fabricated spatial deformation pneumatic leg actuators (SDPLAs), an equivalent dynamic model derived from Euler–Lagrange equations and a modified hysteresis model are established to form the new complete model of SDPLA systems, which accurately describes the bending deformation and hysteresis of SDPLAs at the same time. Furthermore, a novel model‐based adaptive fuzzy tracking controller is designed for SDPLAs, which addresses model uncertainties and unknown external torque, and achieves the accurate bending of each SDPLA part. Subsequently, the closed‐loop stability is rigorously proven by the Lyapunov theory. Finally, a series of experiments validates the effectiveness of the established dynamic and hysteresis models, the tracking control performance on time‐varying trajectories with different amplitudes, frequencies, and shapes, and the control robustness against disturbances.