Modeling and Trajectory Tracking Control for Magnetic Wheeled Mobile Robots Based on Improved Dual-Heuristic Dynamic Programming

In this article, a mathematical model of a magnetic-wheeled mobile robot (MWMR) used for wall climbing in some special industrial sites is established, and to realize the precise motion control of the robot, an intelligent discrete algorithm for trajectory tracking control of the MWMR is presented. The robot is subjected to nonholonomic constraints when moving on the wall. The discrete mathematical model of the MWMR is established with the description of the kinematics and dynamics, where the dynamics are described by the second-order Lagrange's equations. Improved dual-heuristic dynamic programming (DHP) where the actor-critic structure adopts random vector functional link neural networks (RVFL NNs) is the main configuration of the trajectory tracking control algorithm. Moreover, the tracking control algorithm is supplied by a PD controller and a supervisory element to generate overall control signals. The improved strategy is to optimize the input layer weights of RVFL NNs by a genetic algorithm to improve the approximation performance of DHP. Simulations are performed to test the trajectory tracking control algorithm for this wall-climbing robot, and the results are compared with those of neural network tracking control algorithm. Comparative analysis verifies the effectiveness and advancement of the proposed method.