考虑不确定扰动的主动后轮转向动力学控制与试验研究

针对在复杂工况及不确定扰动下主动后轮转向系统角度高精度跟踪控制及抗干扰问题,首先采用可调长度电控束角杆的主动后轮转向机构实现主动后轮转向动作,并对该系统建立其非线性动力学模型。然后,基于动力学模型分析设计主动后轮转角改进自抗扰跟踪控制方法,利用扩张状态观测器对外部和内部扰动进行观测并将扰动补偿到控制器中,以实现高精度角度控制和抗干扰能力。最后,通过试验证明,本文中采用的可调长度电控束角杆转向机构以及改进自抗扰跟踪控制方法能在不确定负载扰动下实现较高精度的角度跟踪控制,并与常规PID控制相比,改进自抗扰控制方法具有较强的鲁棒性和抗干扰性。     

基于曲率控制的紧急避让路径跟踪研究

针对紧急避让工况,提出一种基于曲率控制的路径跟踪控制方法。以车辆二自由度动力学模型为基础,设计基于曲率控制的二阶自抗扰路径跟踪控制器,采用前馈与反馈相结合的复合控制方法进行曲率跟踪控制。为了解决避让过程中侧向加速度过大或产生阶跃、曲率不连续问题,引入三次B样条曲线进行路径跟踪曲率规划,采用CarSim/Simulink联合仿真方法进行控制器性能验证。仿真结果表明,在对接和对开路面工况下,基于曲率控制的路径跟踪控制器能够保证车辆实际行驶路径曲率跟踪理想路径曲率,抵抗外界干扰能力强。     

基于自抗扰控制的轮毂电机驱动电动汽车耦合振动抑制

针对路面随机激励和轮毂电机不平衡电磁激励引起的电磁耦合振动对轮毂电机驱动电动汽车的影响，提出一种基于自抗扰的振动抑制方法。建立车辆1/4振动系统数学模型，设计了一种基于自抗扰的控制器，将路面随机激励和电机自身产生的电磁激励视为总扰动进行统一观测补偿控制，并通过MATLAB/Simulink对所提出的控制策略进行仿真验证。结果表明，自抗扰控制对由路面不平度和偏心电磁力引起的电磁耦合振动具有较好的抑制效果。     

CVT分段参数自调整PID速比控制研究

针对CVT速比控制的特殊要求,在综合考虑常规PID控制经验及控制效果的基础上,设计了分段参数自调整PID速比跟踪控制器。建立了装备CVT系统的整车动力学仿真模型,并利用Matlab/Simuink工具进行了起步、加速和坡道行驶等典型工况的仿真研究。结果表明,该控制器具有较强的鲁棒性和解耦能力,以及良好的动态响应能力和较高的稳态控制精度。     

基于线性自抗扰控制的汽车ABS滑移率控制研究

针对目前滑移率控制的鲁棒性、复杂性与实际应用之间的矛盾,提出基于线性自抗扰控制的ABS滑移率控制方法。首先,对建立的ABS模型进行动态补偿线性化;接着,设计了以观测带宽为参数的扩张状态观测器和以控制带宽为参数的动态补偿控制器,并通过在线估计和补偿未知扰动,提高了系统的鲁棒性;然后,优化带宽系数,实现滑移率零稳态误差的跟踪;最后,通过仿真,验证ABS滑移率的线性自抗扰控制方法的可行性和有效性。结果表明,该方法不仅不依赖于模型,参数调节简单,且具有容错性,在产生噪声和未知扰动时仍能有效跟踪最佳滑移率;滑移率控制器会受ABS制动系统带宽的影响而出现高频振荡现象,在低附着路面上尤为严重,因此ABS设计须充分考虑执行器带宽对ABS滑移率控制的影响。     

金属带式无级变速器夹紧力控制的研究

介绍了金属带式无级变速器控制系统的主要功能,研究了夹紧力控制阀的工作特性,设计了带有前馈抗回绕的PID控制器。对所设计的夹紧力控制系统模型进行了仿真试验,并对装有该夹紧力控制器的综合控制系统进行了装车试验。结果表明,所设计的控制器能够按照行驶工况的要求控制合适的夹紧力,调节速比,可满足实际需要。     

某新型线控转向系统的自适应模糊滑模控制EI北大核心CSCD

为实现一种新型线控转向系统的转角跟踪性能,提出了一种自适应模糊滑模控制(AFSMC)方法。传统的滑模控制(SMC)设计需要预先获得系统扰动量,而AFSMC可通过在线模糊自适应系统实时估计出系统扰动量,进而减弱控制律中的切换项信号,降低了控制系统的保守性和抖振现象。仿真结果表明,AFSMC控制下的线控转向系统具有良好的转角跟踪性能、鲁棒性和能效。     

基于自抗扰的永磁同步电机谐波抑制策略

为了更好地解决电动汽车永磁同步电机的电流畸变现象,从而提高车辆运行稳定性,提出了一种基于自抗扰控制器的谐波抑制策略。使用自抗扰控制器取代传统PI控制器在电机电流环中的作用,通过补偿系统扰动的方式抑制谐波的产生,再与电机控制过程中的谐波抑制算法相匹配,提取出电机控制系统5、7次谐波并进行补偿。使用MATLAB/Simulink仿真并进行试验验证,结果表明,该算法更好地实现了谐波抑制功能,提高了车载永磁同步电机电驱系统的稳定性。     

电液耦合转向系统转向盘转矩的自抗扰控制

为解决商用车电液耦合转向系统由于非线性、参数时变和外界干扰等因素造成的路感差的问题,提出了以理想转向盘转矩为目标的电液耦合转向系统自抗扰控制(ADRC)策略。在分析结构原理的基础上建立了系统的数学模型,针对商用车转向性能需求确定了基于车速和侧向加速度的驾驶员理想转向盘转矩,以此为目标采用自抗扰控制进行目标手力的跟踪。通过施加不同的干扰与PID控制对比仿真,结果表明设计的ADRC控制算法能很好地跟踪转向盘转矩,且具有更高的抗干扰能力,有效地提高了转向盘转矩闭环跟踪控制的鲁棒性。     

基于非线性三步法的DCT两挡起步控制策略研究

为实现双离合器自动变速器(DCT)的两挡联合起步,提出了一种应用非线性三步法跟踪期望起步车速曲线,并能实现两挡联合起步的控制策略。基于汽车动力学设计了由类稳态控制、参考动态前馈、误差反馈3个部分构成的控制器,并通过AMESim和Simulink联合仿真验证提出的控制策略的有效性,结果表明,应用该起步策略可实现起步车速跟踪,同时可平衡起步过程双离合器的滑摩,有效延长离合器总成寿命。     

Idle speed controller based on active disturbance rejection control in diesel engines

This study proposes a design for an idle speed controller to compensate for varying engine load and friction torque in passenger car diesel engines. An active disturbance rejection control (ADRC) framework, comprised of a disturbance compensator and a feedback controller, is applied to an idle speed controller to compensate for disturbances such as engine load and friction torque. In addition, a feedforward compensator is designed into the ADRC framework to improve disturbance rejection performance. The proposed controller is validated by engine and vehicle experiments and the experiment results are compared with a commercial controller.     

双离合器自动变速器换挡过程的内模控制

为提高双离合变速器的换挡过程平顺性,提出内模控制方法,提高离合器转速差的跟踪精度。设计转矩干扰补偿器来减小发动机端与负载端转矩扰动的影响,并基于平滑可微的参考转速差设计超前校正控制器。即使存在模型不确定与干扰,内模控制系统能维持稳定。仿真与台架实验结果表明,在不同参考输入与模型参数情况下,所提出的控制器均能达到较小的跟踪误差和平顺的换挡效果。     

汽车防抱死制动系统的自抗扰控制研究

汽车防抱死制动系统（Anti-lock Braking System,ABS）的作用是确保汽车制动时行驶方向的稳定性、可靠性,但是目前仍存在非线性、时变性以及参数不确定性等问题。为保证汽车制动行驶过程中的操纵稳定性和安全性,进一步实现各工况下防抱死制动系统的优化控制,以影响整车稳定的变量滑移率为研究对象,分析所设计策略的控制效果。搭建汽车动力学模型、制动系统模型、轮胎模型和滑移率模型等主要模型,设计基于滑移率的ABS二阶非线性自抗扰控制器。运用MATLAB/Simulink软件对基于自抗扰控制（Active Disturbance Rejection Control,ADRC）的ABS制动过程和基于模糊PID控制的ABS制动过程进行仿真,对比研究最佳滑移率、载荷、水泥-冰对接路面、扰动等对制动过程中的轮速、车速以及滑移率等动态性征反映的稳定性和抗扰能力的影响,同时研究其对最终制动距离和最终制动时间反映的制动性能的影响。最后,将自抗扰控制器和模糊PID控制器装配于试验车辆的ABS,进行水泥路面和冰-水泥对接路面制动过程的实车试验。研究结果表明：基于二阶非线性自抗扰控制算法的ABS制动的最终制动距离和最终制动时间更短、制动效果更优,制动过程中的轮速、车速和滑移率在响应速度、稳定性和抗扰能力等方面均更佳;试验结果与仿真结果吻合,证明了仿真模型及其仿真结果的可行性和正确性。     

基于扰动观测的智能驾驶主动抗扰纵向车速控制算法

为了减少智能驾驶车辆的纵向车速控制的时滞,提高主动抗扰性,提出一种基于扰动观测的纵向车速控制算法,并进行了实车验证。模型中,采用前馈控制模块,并提前输出控制量,来提高车速跟随的响应性;以主动抗扰控制(ADRC)模块作为反馈环节,采用扩张状态观测器(ESO)在线估计内外部扰动,并在控制端进行补偿,实现了对车速的精确闭环控制。在弯道、环岛等路况下进行了实车实验。结果表明:该算法可以在5 s内控制车速从怠速快速跟踪到目标车速,总体平均误差为0.17 km/h。因而,该算法较传统的比例积分微分(PID)有更好的响应性、控制精度和抗扰性。     

Robust yaw stability control for electric vehicles based on active front steering control through a steer-by-wire system

A robust yaw stability control design based on active front steering control is proposed for in-wheel-motored electric vehicles with a Steer-by-Wire (SbW) system. The proposed control system consists of an inner-loop controller (referred to in this paper as the steering angle-disturbance observer (SA-DOB), which rejects an input steering disturbance by feeding a compensation steering angle) and an outer-loop tracking controller (i.e., a PI-type tracking controller) to achieve control performance and stability. Because the model uncertainties, which include unmodeled high frequency dynamics and parameter variations, occur in a wide range of driving situations, a robust control design method is applied to the control system to simultaneously guarantee robust stability and robust performance of the control system. The proposed control algorithm was implemented in a CaSim model, which was designed to describe actual in-wheel-motored electric vehicles. The control performances of the proposed yaw stability control system are verified through computer simulations and experimental results using an experimental electric vehicle.     

Nonlinear feedforward–feedback control of clutch-to-clutch shift technique

To improve the shift quality of the vehicle with clutch-to-clutch gear shifts, a nonlinear feedforward–feedback control scheme is proposed for clutch slip control during the shift inertia phase. The feedforward control is designed based on flatness in consideration of the system nonlinearities, and the linear feedback control is given to accommodate the model errors and the disturbances. Lookup tables, which are widely used to represent complex nonlinear characteristics of powertrain systems, appear in their original form in the designed feedforward controller, while the linear feedback controller is calculated through linear matrix inequalities such that the control system is robust against the parameter uncertainties. Finally, the designed controller is tested on an AMESim powertrain simulation model, which contains a time-variant model of clutch actuators.     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

线控转向系统转角反步控制算法研究

为实现商用车线控转向,设计一套新的线控转向系统架构及其转角跟踪控制算法。新的线控转向系统采用丝杠螺母结构中的丝杠直接控制纵拉杆,螺母通过带轮机构被电机驱动。对线控转向系统结构进行运动学分析,推导转向系统可变传动比,采用前轮转角为状态变量,建立线控转向系统二阶动力学模型。基于转角跟踪目标,采用反步控制算法,设计线控转向系统转角跟踪控制器,通过反馈系统线性化处理系统参数不确定和环境干扰问题,实现准确的目标转角跟踪,并建立李雅普诺夫函数,证明了采用反步控制的线控转向系统是渐进稳定的。搭建采用“丝杠螺母+带轮机构”架构的线控转向实车底盘测试台架,选取蛇形和混合工况进行控制算法验证。研究结果表明：与滑模控制算法的测试结果对比可知,反步控制算法绝对平均跟踪误差值降低了71.88%~79.57%,跟踪误差标准偏差值降低了71.32%~78.50%;线控转向系统反步控制转角跟踪算法能够减少系统收敛到原点的时间,抑制系统的抖振,提高车辆线控转向系统转角跟踪的操纵灵活性。     

无人驾驶机器人车辆非线性模糊滑模车速控制

为了实现不同行驶工况下车速的精确、稳定控制，提出一种基于非线性干扰观测器的无人驾驶机器人车辆模糊滑模车速控制方法。考虑模型不确定性和外部干扰对车速控制的影响，建立车辆纵向动力学模型。通过分析无人驾驶机器人油门机械腿、制动机械腿的结构、机械腿操纵自动挡车辆踏板的运动，建立油门机械腿和制动机械腿的运动学模型。在此基础上，分别设计油门/制动切换控制器、油门模糊滑模控制器以及制动模糊滑模控制器，并进行控制系统的稳定性分析。油门/制动切换控制器以目标车速的导数为输入来进行油门与制动之间的切换控制。油门模糊滑模控制器和制动模糊滑模控制器以当前车速以及车速误差为输入，分别以油门机械腿直线电机位移和制动机械腿直线电机位移为输出来实现对油门与制动的控制。模糊滑模控制器中，为了减少控制抖振，滑模控制的反馈增益系数由模糊逻辑进行在线调节。模糊滑模控制器中的非线性干扰观测器用于估计和补偿无人驾驶机器人车辆的模型不确定性与外部干扰。仿真及试验结果对比分析表明：本文方法能够精确地估计和补偿无人驾驶机器人车辆的模型不确定性和外部干扰，避免了油门控制与制动控制之间的频繁切换，并实现了精确稳定的车速控制。