窄体车辆转向与侧倾同步控制研究

Research on Synchronous Control of Steering and Tilting for Narrow Vehicles

为了解决窄体车辆过弯易侧翻的问题,研究一种采用转向和侧倾并联机构的窄体侧倾车辆,通过控制车辆在转弯时主动向弯道内侧倾斜的程度,提高车辆弯道行驶时的安全性;针对车辆在转向和侧倾控制过程中存在的响应不同步问题,提出一种基于模糊控制的同步控制策略。首先,对采用转向和侧倾并联机构的窄体侧倾车辆进行结构原理分析,并建立转向轮模型和车辆3自由度模型。然后,对侧倾控制系统的响应特性在线辨识,通过模糊控制得到因悬架阻尼力作用引起的侧倾响应时滞量,并对转向动作进行相应延时,从而实现转向与侧倾的同步控制;同时,分别确立期望的前轮转向角和整车侧倾角,通过PID控制使实际转向角和侧倾角跟踪期望值。最后,分别基于MATLAB/Simulink和试制的窄体侧倾样车进行仿真和试验分析。研究结果表明:窄体侧倾车辆的悬架阻尼力导致侧倾动作的响应时间明显大于转向动作的响应时间,从而导致车辆的转向和侧倾不能实现同步控制;单移线和S弯转向试验结果表明,所提控制策略能够有效改善转向和侧倾的响应不同步现象,从而将窄体侧倾车辆在转弯时的侧向加速度和侧倾作动器的峰值扭矩分别减小67.9%以上和48.4%以上,有效防止了窄体车辆转向时的侧翻危险,降低了系统的成本和能耗。

A narrow tilting vehicle with parallel steering and tilting mechanism is studied because narrow tilting vehicles tend to roll over when cornering.Controlling the vehicle leaning degree to the inside of a curve improves the vehicle's safety in a curve.A synchronous control strategy based on fuzzy control was proposed to address the asynchronous response of the vehicle during steering and tilting control.First,the structural principle of the narrow-tilting vehicle with parallel steering and tilting mechanism is analyzed,and a steering wheel and vehicle three-degree-of-freedom models are established.Subsequently,the response characteristics of the tilt control system are identified online,and the tilt response delay caused by the suspension damping force is obtained through fuzzy control.Based on these characteristics,the steering action is delayed to synchronize steering and tilting control.Simultaneously,the desired steering angle of the front wheel and vehicle tilting angle is determined,and the actual steering and tilting angles track the desired value through PID control.Finally,simulation and experimental analyses were conducted on MATLAB/Simulink and a trial-produced prototype vehicle.The simulation and test results of angular step steering show that the suspension damping force of the narrow-tilting vehicle makes the response time of the tilting action significantly longer than that of the steering action,which results in the failure of the synchronous control of vehicle steering and tilting.Moreover,singleshift and S-shape steering tests show that the proposed control strategy can effectively improve the synchronous response of steering and tilting,reducing the lateral acceleration and peak torque of the tilt actuator by more than 67.9%and 48.4%,respectively,when a narrow-tilting vehicle is turning.Moreover,it prevents rollover when the narrow vehicle is turning and reduces the cost and energy consumption of the system.