Whole-Body Control of an Autonomous Mobile Manipulator Using Series Elastic Actuators

The flexible-joint robot has superior attractive features because of its high mobility, high load ratio, high torque fidelity, robustness for external disturbance, task adaptability, and safety. In this article, an autonomous mobile manipulator driven by the designed series elastic actuators is developed. A complete dynamic model of a nonholonomic mobile manipulator including a mobile platform and a manipulator with joint flexibility operating simultaneously is proposed. An integrated whole-body trajectory control framework is proposed for such robot to perform mobile manipulation tasks. Considering the nonholonomic and holonomic constraints in the mobile manipulation, the whole-body dynamics is formulated and reduced. To address the highly nonlinear of the dynamics and model uncertainty, a novel integral Lyapunov function based adaptive neural network control for task tracking under uncertainties of the flexible-joint robot model is proposed. Compared with existing methods, the proposed method provides an alternative for controlling flexible-joint robots. The feasibility of the proposed method is verified by the extensive trajectory tracking experiment results in our developed flexible joint manipulator.