Research on obstacle avoidance control of mine vehicles based on spatial model predictive control

Aiming at the problem of the reference track smoothness of mine vehicle in the real-time obstacle avoidance process of roadway and the damage caused by the sudden change of turning angle to mine vehicle structure and steering components in the track tracking process, an improved mine vehicle obstacle avoidance controller based on the spatial model predictive control (SMPC) algorithm was designed.The design process of mine vehicle obstacle avoidance controller is as follows.Firstly, combining with model predictive control principle and Curvilinear coordinate system, the Cartesian coordinates of the vehicle kinematic model based on time t is converted into the Curvilinear Coordinates of deviation model based on space s.Mine vehicle deviation model predictive equation is deduced by using Taylor method to linearize and Euler method to discrete.Secondly, in the part of track tracking, the objective function is set to optimize the first and second derivatives of vehicle steering curvature and lateral displacement deviation.While in the part of trajectory reprogramming, the boundary function is set based on obstacle information and roadway boundary information, and the objective function is set to optimize the transverse deviation value and its first and second derivatives.Finally, the objective function is transformed into quadratic programming problem to solve the optimal control sequence.A simulation platform was built to simulate underground roadway environment and a real-time simulation verification was carried out on the proposed mine vehicle obstacle avoidance controller.The results show that the improved controller can keep the lateral displacement deviation between the vehicle and the reference trajectory within 0.2 m and the heading angle deviation within 0.09 rad in track tracking.Compared with the traditional MPC control algorithm, the improved controller has a better accuracy and stability.In terms of real-time obstacle avoidance, the control performance of the controller is affected by the road curvature.However, no matter in the case of single obstacle or continuous multiple obstacles, the vehicle can avoid the obstacle and obtain a smooth steering input and a smooth and accurate driving track.