Design and validation of a robust active trailer steering system for multi-trailer articulated heavy vehicles

ABSTRACT

Multi-trailer articulated heavy vehicles (MTAHVs) are increasingly used around the world due to their economic and environmental benefits. However, MTAHVs exhibit poor maneuverability and low lateral stability, which may lead to fatal traffic accidents. Given the safety risks, it is necessary to solve the steering and stability problems of MTAHVs before they are safely mass deployed on our roads. To this end, active trailer steering (ATS) based on the linear quadratic regulator (LQR) technique has been explored. The LQR-based ATS demonstrates improved maneuverability and enhanced lateral stability. In the ATS design, the vehicle and operating parameters are assumed constant. Thus, it is natural to question the robustness of the ATS in presence of vehicle and operating parameter uncertainties. To address the problem, this paper proposes a robust ATS system. The robust ATS controller is designed using a linear matrix inequality (LMI) based LQR method. In the design, both vehicle and steering actuator parameter uncertainties are considered; to enhance the robustness of the ATS, the weighting matrices of the proposed controller are optimized. The robust controller is applied to an A-Train Double, one type of MTAHV. The effectiveness of the robust ATS is demonstrated using numerical and hardware-in-the-loop real-time simulations.     

Actuator optimal placement studies of high-speed power bogie for active hunting stability

ABSTRACT

We put forward three actuator placements of the high-speed train power bogie to improve the train hunting stability. The active control forces act on the frame, between the frame and the motor, and on the motor by the inertial or retractable actuator, respectively, based on the feedback states of vibration velocity of the front and rear end beams. The feedback gains and the motor suspension parameters in different cases are optimised with the two objectives of system stability margin and control effort. The required actuator outputs of the three cases are compared based on the theoretical analysis with a 8 DOF bogie model. The results show that the three control cases can effectively improve the hunting stability, especially at high speed. The active control of motor lateral movement is helpful to increase the dynamic vibration absorbing function of the motor flexible suspension, and the control output is obviously smaller than the other two control cases. In addition, the influence of system delay on stability was analysed and we could use or avoid the effects of delay on the stability.     

Risk management algorithm for rear-side collision avoidance using a combined steering torque overlay and differential braking

This paper describes a risk management algorithm for rear-side collision avoidance. The proposed risk management algorithm consists of a supervisor and a coordinator. The supervisor is designed to monitor collision risks between the subject vehicle and approaching vehicle in the adjacent lane. An appropriate criterion of intervention, which satisfies high acceptance to drivers through the consideration of a realistic traffic, has been determined based on the analysis of the kinematics of the vehicles in longitudinal and lateral directions. In order to assist the driver actively and increase driver's safety, a coordinator is designed to combine lateral control using a steering torque overlay by motor-driven power steering and differential braking by vehicle stability control. In order to prevent the collision while limiting actuator's control inputs and vehicle dynamics to safe values for the assurance of the driver's comfort, the Lyapunov theory and linear matrix inequalities based optimisation methods have been used. The proposed risk management algorithm has been evaluated via simulation using CarSim and MATLAB/Simulink.     

基于反步法的欠驱动吊艇架主动式减摆控制

针对欠驱动的三维吊艇架系统,提出了基于反步法的主动式减摆控制方法。建立了三维吊艇架系统的动力学模型,采用反步法设计了吊艇架的减摆控制装置,和其他船用吊艇架的减摆控制相比,采用主动式减摆,结构紧凑,且对负载质量和吊绳长度不确定的情况下,依然可实现对吊艇摆动的有效抑制。仿真结果表明了该减摆控制器有着良好的减摆效果。     

延时对有源滤波器补偿性能的影响

采用有源滤波技术对舰船大容量独立交流电力系统的电能质量进行综合治理已成为必然趋势。本文以三相三线并联型有源滤波器为研究对象,分析了造成并联型有源滤波器补偿电流响应时间延迟的成因,推算了不同阶次谐波的补偿失效率和时间延迟的关系,提出了针对补偿延时的超前拍PI控制策略。仿真和样机实验证实了理论的正确性。     

基于三电平APF的新型无差拍控制器研究

本文以三线四线制三电平三桥臂电容中分型APF的谐波补偿作为研究内容,分析了控制量一拍滞后实施对传统无差拍控制的影响,提出了一种改进型无差拍控制,在系统模型参数精确的情况下,将完全消除电压控制量一拍滞后实施的影响。实验结果表明改进无差拍控制器较好地计算出合适的电压控制量,证明改进无差拍的正确性和可行性。     

路堑边坡防护方案探讨

边坡对道路工程的安全有着重要的影响,本文结合工程实例,分析了不同类型边坡适合采用的边坡防护形式,针对性强,既满足安全要求,又注意与绿化相结合,具有较强的工程适用性。     

库仑土压力计算新方法——扫描搜索法

库仑土压力理论是解决土压力问题的最简途径之一,但传统的计算方法公式繁多、工作量大,且不适用于复杂坡面的情况。为解决该问题,提出一种快速求解库仑主动土压力的新方法——扫描搜索法。该方法无需先求取破裂角,而是以墙背某一点为起点,以该点到坡面线的连线为破裂面,按照一定间距变化地面上各点扫描墙后土体,得到所有可能的破裂面,利用坐标求取破裂棱体的自重及形心,根据推导的库仑土压力计算通式计算土压力的大小和作用点的位置,最终搜索出最大土压力。利用该方法结合计算机编程,可快速准确地计算各种复杂坡面荷载及工况下的墙背土压力。算例对比表明,该方法所得结果与库仑公式法所得结果基本一致。     

圆柱壳振动噪声研究与控制的研究综述

圆柱壳是潜艇、飞机、火箭以及轨道列车的主要结构,对圆柱壳振动噪声的研究与控制具有重要军事、政治与经济利益.本文对关于圆柱壳振动噪声的研究与控制工作进行了分析与归纳,并对未来的研究趋势进行了合理预测.     

皮卡式清障车总体设计及市场应用

通过对高速针对常规清障车由于超高、转弯空间受限无法进入地下车库进行施救的难题,文章提出了专用皮卡式清障车的总体功能要求,探讨了总体布置、底盘选型与改造、专用装置结构设计等关键技术,研发并制造了皮卡式清障车样机,并进行了相应功能验证。在此基础上,深入剖析了皮卡式清障车在市场应用中所遇到的问题,并提倡将"主动救援新模式"常态化。