露天矿山运输车辆无人驾驶纵向精准停车控制策略研究

Research on Longitudinal Precise Parking Control of Unmanned Vehicles in Open-pit Mines

目前,在矿区复杂路况下,露天矿山运输车辆自动驾驶排卸时存在着溜车、冲撞挡墙和急刹车等一系列现象,严重影响车辆纵向精准停车。对此,文章提出了一种面向露天矿山无人驾驶运输车辆的分布式纵向自适应精准停车控制策略。首先,其上层控制器根据状态反馈跟踪控制方法计算得到车辆的期望加速度,再根据坡道阻力和滚动摩擦力计算得到车辆的理论加速度;然后,由下层控制器采用逆动力学方式控制车辆的油门开度及电制动力百分比,实现倒车过程中的车速平稳。现场实车测试结果表明,采用所设计的分布式控制方法,极大地改善了溜车、冲撞挡墙和因速度过高而出现的急刹车等问题,并实现了距离终点仅0.19 m的停车精度,较采用“前馈+PI控制”策略的0.50 m停车精度具有较大程度的提升。

At present, under the complex road conditions in the mining area, there are a series of phenomena such as slippage, collision with the retaining wall and sudden braking when open-pit mine transportation vehicles are automatically driven and unloaded, which seriously affects the longitudinal and precise parking of vehicles. In this regard, this paper proposes a distributed longitudinal adaptive precise parking control strategy for open-pit mine transportation vehicles. First, the upper-layer controller calculates the expected acceleration of the vehicle according to the state feedback tracking control method, and adds slope resistance and rolling friction to calculate the theoretical acceleration of the vehicle. Then, the lower-layer controller uses inverse dynamics to control the accelerator opening and electrical braking percentage to achieve stable vehicle speed during reversing. Field test results show that the distributed control method designed in this paper can greatly improve the problems of rolling, collision with the retaining wall and sudden braking due to high speed, and realize the parking accuracy of only 0.19 m from the end point, which has a greater improvement than the 0.50 m parking accuracy of the "feedforward+PI control" strategy.