Output feedback stabilization control for underactuated mechanical systems

This paper is focused on the output feedback stabilization control problems for a special class of underactuated mechanical systems, which appear in robotics and aerospace applications. For the synthesis of controller, firstly, the considered underactuated mechanical system is explicitly transformed into two cascade connected subsystems, and then an auxiliary filter based virtual stabilization controller is developed to locally asymptotically stabilize the first subsystem. Further, the designed virtual controller is again involved into the second subsystem using backstepping procedure to construct the actual control law. Lyapunov analysis shows the local asymptotic stability of the closed-loop system. Simulation results are presented by using a benchmark nonlinear underactuated mechanical system to prove the feasibility and the effectiveness of the proposed controller.