The virtual track train (VTT) is a new type of urban transit system with all-wheel active steering technology utilized to make the long combination vehicle run along the planned route (virtual track) like railway vehicles along physical track. This paper proposed a scalable cascade modular path following control strategy for the newly designed gantry virtual track train (G-VTT) based on preview & tracking controller, focusing on the lateral control for low-speed turning manoeuvre. The mathematical characteristics of the 2-norm was utilized to establish a local tracking objective function (LTOF) to find the optimal lateral acceleration (OLA) of the tracking point in the preview window and calculate the optimal wheel steering angle (WSA) to achieve the optimal local trajectory. Considering the lag time Td, the yaw stability and path following ability of the vehicle are contradictory in some cases, so the damping adjustment factor λ was proposed to optimize the damping characteristics and the time-delay stability factor ξ was proposed to evaluate the time-delay stability. The influence of the key parameters, preview time Tp, Td, ξ and λ, on the stability and following ability were analyzed by frequency domain analysis method, and the optimal region of ξ and λ was obtained to instruct the configuration of λ and Tp. Finally, steady-state and dynamic forward predictive models were proposed to compensate for the oscillation caused by the lag time. The effectiveness of the proposed control strategy, forward predictive models and the configuration method of λ and Tp were verified by theoretical analysis and numerical simulation.

中文翻译：

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门式虚拟轨道列车级联模块化路径跟踪控制策略：时滞稳定性和前向预测模型


虚拟轨道列车（VTT）是一种新型城市交通系统，采用全轮主动转向技术，使长组合车辆像铁路车辆沿着物理轨道一样沿着规划路线（虚拟轨道）运行。本文针对新设计​​的龙门虚拟轨道列车（G-VTT）提出了一种基于预览和跟踪控制器的可扩展级联模块化路径跟随控制策略，重点关注低速转弯操纵的横向控制。利用2-范数的数学特性，建立局部跟踪目标函数（LTOF），寻找预览窗口中跟踪点的最佳横向加速度（OLA），并计算最佳车轮转向角（WSA），从而实现最优局部轨迹。考虑到滞后时间Td，车辆的横摆稳定性和路径跟随能力在某些情况下是矛盾的，因此提出阻尼调整因子λ来优化阻尼特性，并提出时滞稳定因子ϋ来评估时滞稳定性。延迟稳定。采用频域分析方法分析了关键参数预览时间Tp、Td、ψ、λ对稳定性和跟随能力的影响，得到了ψ、λ的最优区域，指导λ、Tp的配置。最后，提出了稳态和动态前向预测模型来补偿滞后时间引起的振荡。通过理论分析和数值仿真验证了所提出的控制策略、前向预测模型以及λ和Tp配置方法的有效性。