Near minimum-time control of robotic manipulator with obstacles in the workspace

The authors consider the development of a near-minimum-time suboptimal controller for a robot manipulator to follow a prespecified path which is designed to avoid obstacles in the workspace. A dynamic model for the manipulator, which is simple to manipulate, is established using the average dynamics method of linearization. The model has the advantage of being continuously updated over the control time periods. This makes it suitable for high-speed or variable-payload applications. Bang-bang control theory in conjunction with synchronization of executing time for each joint is used to derive the suboptimal controller. Simulation results under different conditions of obstacles and loads indicate that the desired controller moves the manipulator around the obstacles in near minimum time with an acceptable level of accuracy