High-Precision Trajectory Tracking System for Fork-Shaped Mobile Robot Based on Cascade S_MPC Control

Abstract

For the fork mobile robot that regulates wheel speed and turning angle based on wheel-ground interaction, it is easily affected by the load, road friction coefficient change and motor output, and there are certain errors in trajectory tracking. In order to solve the above problems, this paper proposes a new sliding mode model predictive control (S_MPC) algorithm and establishes a dual-layer trajectory tracking control framework, in which the upper controller is the model predictive control, and the saturation function containing the boundary layer is introduced in the lower sliding mode control instead of the symbolic function, in order to reduce the jitter in the output of the system, and at the same time ensure the asymptotic stability of the system. Experiments verify the effectiveness of the proposed dual-loop S_MPC control scheme for trajectory tracking of fork-shaped mobile robots. Compared with the classical MPC method and the SMC_JSY control method, the method can reduce the tracking error by about 93% and 97%, and the results show that the method has high accuracy, high efficiency, safety, and applicability to fork-shaped mobile robots.