Three Recurrent Neural Networks and Three Numerical Methods for Solving a Repetitive Motion Planning Scheme of Redundant Robot Manipulators

Three neural networks and three numerical methods are investigated, developed, and compared to solve a repetitive motion planning (RMP) scheme for remedying joint-drift problems of redundant robot manipulators. Three recurrent neural networks, i.e., a dual neural network, a linear variational inequality (LVI)-based primal-dual neural network, and a simplified LVI-based primal-dual neural network, are recurrent and real time, and they do not need to be trained in advance. Three numerical methods, i.e., the 94LVI method, the E47 method, and the M4 method, are time discrete and ready to conduct in digital computers. All these solutions have global linear convergence. Computer simulations and physical robot experiments verify that they are all effective to solve the RMP scheme. The comparisons show that neural networks are more accurate and faster than numerical methods on the same simulated condition under the majority normal circumstances. Furthermore, numerical methods are easy to be applied in digital computers since they are time discrete.