考虑执行器延迟的无人矿卡轨迹跟踪控制研究

Trajectory tracking control of unmanned mining truck considering actuator delays

  • 摘要: 露天矿区无人矿卡运行过程中存在执行器执行延迟大的显著特点,导致轨迹跟踪控制精度较低、运行稳定性较差。针对上述问题,提出一种考虑执行器延迟的无人矿卡轨迹跟踪控制策略。首先,采用“一阶惯性环节+纯时滞环节”复合模型对横纵向执行器的延迟特性进行精确建模,以此搭建纵向动力学模型和横向轨迹跟踪运动学误差模型。然后,采用横纵向控制解耦架构,分别构建纵向模型预测控制(MPC)与横向非线性模型预测控制(NMPC)优化问题,在目标函数中引入跟踪精度、运行经济性及行驶安全性指标,同时在约束条件中考虑执行器的性能限制,以保证控制输入的可行性与系统稳定性。最后,在解耦架构中加入预测时域内的车辆状态双向交互机制,实现横纵向控制器的协同控制。基于露天煤矿实际道路场景,选取930E型矿用自卸车为对象,进行硬件在环仿真实验和实车测试,并与矿区中已落地应用的实车控制器进行对比验证,结果表明所提控制器在跟踪精度与控制平顺性上均优于对比方案:仿真工况下横向位移、航向角、速度跟踪误差峰值分别降低65.5%,77.1%,71.4%,实车测试中3项误差峰值分别降低61.3%,57.1%,35.1%,运行效率提升9.6%。实车测试中所提控制器的单步计算平均耗时约为1.7 ms,满足无人驾驶系统的实时控制要求,进一步验证了其工程可行性。

     

    Abstract: Unmanned mining trucks operating in open-pit mines have substantial actuator delays, resulting in low trajectory tracking accuracy and poor operational stability. To address this problem, a trajectory tracking control strategy that considers actuator delays was proposed for unmanned mining trucks. First, a composite model comprising a first-order inertia element and a pure time-delay element was used to accurately model the delay characteristics of the lateral and longitudinal actuators. Based on this model, a longitudinal dynamic model and a lateral trajectory-tracking kinematic error model were established. Then, a decoupled lateral-longitudinal control architecture was adopted, and optimization problems were formulated for longitudinal Model Predictive Control (MPC) and lateral Nonlinear Model Predictive Control (NMPC), respectively. Tracking accuracy, operational economy, and driving safety were incorporated into the objective functions, while actuator performance limits were included in the constraints to ensure feasible control inputs and system stability. Finally, a bidirectional vehicle-state interaction mechanism over the prediction horizon was introduced into the decoupled architecture to coordinate the lateral and longitudinal controllers. Using actual road scenarios from an open-pit coal mine, Hardware-in-the-Loop (HIL) simulations and real-vehicle tests were conducted with a mining dump truck (model 930E), and the proposed controller was compared with an in-service vehicle controller already deployed at the mine. Results showed that the proposed controller outperformed the comparison scheme in tracking accuracy and control smoothness. Under simulation conditions, peak lateral, heading-angle, and velocity tracking errors were reduced by 65.5%, 77.1%, and 71.4%, respectively. In the real-vehicle tests, the corresponding peak errors were reduced by 61.3%, 57.1%, and 35.1%, respectively, and operational efficiency was improved by 9.6%. The proposed controller required an average of approximately 1.7 ms per computation step. This computation time meets the real-time control requirements of autonomous driving systems and further demonstrates the engineering feasibility of the proposed controller.

     

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