Fiber-Reinforced Soft Bending Actuator Control Utilizing On/Off Valves

Soft fluid-driven robots have great potential for safe interaction with humans, and for adaptation to complex and unpredictable environments with the compliance brought about by soft materials. However, the respective complex structure and massive use of nonlinear and viscoelastic soft materials, and the nonlinear fluid-driven dynamics, result in the nonlinear dynamic behavior of soft robots, and thus pose great challenges to system modeling and dynamic control. In this study, a complete model is first established by considering the nonlinear behavior of fiber-reinforced soft bending actuator (FRSBA) and the nonlinear dynamics of pneumatic system regulated by two high-speed on/off valves. Notably, the nonlinear dynamic behavior of FRSBA is first identified as parametric uncertainties using the multi-sine pressure excitation signal, and the effects of nonlinear pneumatic system are fully taken into account. Then, an adaptive robust controller is designed to handle the system nonlinearities with a guaranteed transient and steady-state performance. Finally, the comparative experiments demonstrate the effectiveness of proposed modeling method and high performance of adaptive robust controller