Optimal Control Based Path Planning for Parallel Kinematic Manipulators Utilising Natural Motion

Industrial robots performing pick and place operations account for a major part of the energy consumption in packaging and assembling industry. Because of increasing energy prices and the wish for sustainable technologies, methods to reduce the energy consumption of robot manipulators gain in importance. The repetitive character of pick and place operations allows to reduce the energy consumption of the manipulator by adding elastic elements in the joints of the manipulator and utilising the system's dynamics. To use this method a tailored path planning algorithm is needed, which will be presented in this paper, on the example of a five-bar linkage parallel manipulator. The proposed algorithm is based on the optimal control theory. The solution of the resulting boundary value problem is conducted within MATLAB. By simulations it will be shown that this method allows to reduce the energy consumption by up to 84 %.