Lyapunov-based nonlinear controllers for obstacle avoidance with a planar nn-link doubly nonholonomic manipulator

A mobile manipulator is a robotic system made up of two components; a mobile platform and a manipulator mounted on the platform equipped with non-deformable wheels. Such a combined system requires complex design and control. This paper considers the autonomous navigation problem of a nonholonomic mobile platform and an nn-link nonholonomic manipulator fixed to the platform. For this planar nn-link doubly nonholonomic manipulator, we present the first ever set of nonlinear continuous controllers for obstacle avoidance. The controllers provide a collision-free trajectory within a constrained workspace cluttered with fixed obstacles of different shapes and sizes whilst satisfying the nonholonomic and kinodynamic constraints associated with the robotic system. An advantage of the proposed method is the ease at which the acceleration-based control laws can be derived from the Lyapunov function. The effectiveness of the nonholonomic planner is demonstrated via computer simulations.

► We consider motion planning and control of a Type (nh,nh)(nh,nh) manipulator with nn links.
► Newly constructed rod-shaped obstacles are introduced to the workspace.
► We utilize the Lyapunov-based Control Scheme.
► New and unique potential field functions are introduced to the Total Potentials.
► We design continuous time-invariant acceleration-based nonlinear controllers.