A Novel Hybrid Control Strategy for an Underactuated 3-D Biped with Asymmetric Structure

In reality, due to the manufacturing error or the component loss in the service process, the structural parameters of bipedal robots may exhibit asymmetry. In this work, we consider the stable walking of an underactuated 3-D bipedal robot with asymmetric structure, and a novel hybrid control strategy is proposed. The control strategy consists of a continous heuristic motion controller, which asymptotically drive the state of the robot to the zero dynamics manifold, and an event-based feedback controller that renders the hybrid zero dynamics locally asymptotically stable. The heuristic motion controller uses heuristic state variables as controlled variables rather than simply the actuated variables, and the controller parameters of the event-based feedback controller are designed in an analytical method rather than relying on the left–right symmetry property. The effectiveness of the presented control strategy is illustrated by a numerical simulation example.