Thanks to their continuously deformable structure, continuum soft robots are suited for safe human-robot interactions. However, the executable tasks are still limited in complexity due to the high number of degrees of freedom, and the consequent under-actuation that characterizes these robots complicates the control problem. To develop a control strategy taking advantage of the main system properties this letter investigates the use of Interconnection and Damping Assignment Passivity Based Control in the regulation of unstable equilibria of the underactuated template model soft inverted pendulum with affine curvature. We show that remarkably, the partial differential equations that arise from the application of this technique, have a closed-form solution for this system. We verify the effectiveness of the controller via simulations, and we compare the results achieved considering the swing-up problem against the ones obtained with baseline controllers, i.e., Proportional Derivative control and Feedback Linearization.

Keywords: Control applications, robotics, stability of nonlinear systems.

File: https://ieeexplore.ieee.org/abstract/document/10538375