Backstepping Control for Tracking of Solenoid Valve Actuated Pneumatic Continuum Soft Robots

Among the different soft robot types developed, pneumatic continuum soft robots are nowadays the most widely researched type due to their highly compliant behaviour, but their modeling and control remain challenging tasks given its distribute parameters nature and the nonlinearities of its elastomer material. These nonlinearities are aggravated by considering pneumatic actuation dynamics, leading to a highly complex system. While pneumatic actuation dynamics is usually not taken in account for the design of feedback controllers, experiments have shown that they are far from negligible. In this paper, we study a highly coupled nonlinear model that relates the Lagrangian dynamics approach of a continuum soft robot and the pressure dynamics of its embedded pneumatic chambers. Then, a model-based feedback control strategy based on backstepping is proposed for the tracking of a pneumatic continuum soft robot configuration, achieving exponential stability. Finally, simulations are presented and concluding remarks are discussed.