Robust Energy Shaping Control of an Underactuated Inverted Pendulum
M. Reza J. Harandi, Mehrzad Namvar
TL;DR
The paper tackles the challenge of stabilizing underactuated systems by applying interconnection and damping assignment passivity-based control (IDA-PBC) to the rotary inverted pendulum (RIP). It delivers a precise, analytical solution to the kinetic- and potential-energy matching PDEs, enabling exact total energy shaping with a designed $M_d(q_2)$ and $V_d(q)$ and a region of attraction that can be enlarged via controller parameters. A novel robust term is incorporated to reject a class of nonintegrable matched disturbances, with a Lyapunov-based proof guaranteeing closed-loop stability. Numerical simulations demonstrate upright stabilization and robust disturbance rejection, highlighting practical viability and providing a foundation for future hardware implementation and port-Hamiltonian system extensions.
Abstract
Although the stabilization of underactuated systems remains a challenging problem, the total energy shaping approach provides a general framework for addressing this objective. However, the practical implementation of this method is hindered by the need to analytically solve a set of partial differential equations (PDEs), which constitutes a major obstacle. In this paper, a rotary inverted pendulum system is considered, and an interconnection and damping assignment passivity-based control (IDA-PBC) scheme is developed by deriving concise analytical solutions to the kinetic and potential energy PDEs. Furthermore, a novel robust term is incorporated into the control law to compensate for a specific class of disturbances that has not been addressed within the existing IDA-PBC literature. The effectiveness of the proposed method is validated through numerical simulations, demonstrating satisfactory control performance.
