无人车路径跟踪数据采样输出反馈控制

Sampled-Data Output Feedback Control for Path Tracking of Driverless Vehicle

  • 摘要: 针对无人车转弯过程存在不确定项导致的扰动增加,进而影响行驶精度的问题,以及自主导航系统GPS-RTK信号接收频率过低导致的非实时数据更新的问题,该研究设计了状态观测器与数据采样控制器。建立无人车的偏差模型,并引入坐标变换,得到其运动学模型。通过构建状态观测器,对系统状态进行估计,进一步设计数据采样输出反馈控制器,并对系统的稳定性进行了分析。最后,通过仿真与实验证明了所设计的控制器能够使系统稳定,并在实验中与Stanley控制算法进行对比验证了其优越性。在相同参数条件下,与Stanley控制器相比,设计的数据采样控制器导航精度显著提高,车辆上线后,直线路径跟踪横偏最大误差不超过10 cm,转弯路径跟踪横偏最大误差不超过50 cm,能够较好满足无人车导航行驶需求。

     

    Abstract: To mitigate the increased disturbance induced by parametric uncertainties during turning maneuvers, which severely degrade path-tracking accuracy, and to compensate the non-real-time data updates caused by the low update frequency of GPS-RTK signals in the autonomous navigation system, this study designs a state observer and a sampled-data controller. By establishing a deviation model for the unmanned vehicle and introducing coordinate transformation, its kinematic model is derived. A state observer is constructed to estimate the states of the system, and a sampled-data output feedback controller is designed, with an analysis of the system stability. Finally, simulations and experiments demonstrate that the designed controller can stabilize the system and outperforms the Stanley controller. Under the same parameter conditions, compared to the Stanley controller in the experiment, the designed sampled-data controller significantly improves the navigation accuracy. After the vehicle is launched, the maximum lateral offset for straight path tracking does not exceed 10 cm, and the lateral offset for curved path tracking does not exceed 50 cm, which can well meet the navigation requirements of the driverless vehicles.

     

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