基于滑模变结构控制的叉车线控转向系统研究

发布时间：2018-02-14 23:51

本文关键词： 三轮叉车线控转向系统理想传动比滑模控制操纵稳定性　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着现代物流行业的迅速发展,巨大的竞争压力已经使得传统的人工搬运方式无法在运输效率上取得优势,因此以叉车为主的机械化搬运得到了企业的重视,叉车迎来了扩大发展的机遇。同时线控转向系统的引入为车辆转向系统带来了新的发展理念和技术革新,适用于频繁转向的叉车,可以解决传统转向中存在的弊端,因此对叉车的线控转向技术研究具有重要的理论和实际意义。本文以三轮转向叉车为研究对象,针对三轮线控叉车转向稳定性和车轮转角跟踪问题,以三轮叉车后轮转向动力学模型和叉车线控转向系统数学模型为基础;然后基于横摆角速度增益恒定的理想变传动比控制策略得到目标后轮转角,并考虑到叉车转向执行机构中不确定参数的约束信息、不确定回正力矩以及路面的干扰信息,设计了滑模变结构转角跟踪控制策略。仿真结果表明,通过以上两种控制策略的结合,提高了叉车转向的灵敏性和稳定性;同时有效抑制了线控转向系统内部的参数摄动和外部干扰,改善了车轮转角跟踪性能。为了改善传统后轮叉车转向性能的不足,对全转向线控三轮叉车二自由度转向动力学模型进行了研究。从人-车闭环角度出发,结合叉车操纵稳定性综合评价指标与遗传算法,优化得出叉车行驶过程中的理想横摆角速度增益。以零化质心侧偏角和跟踪理想横摆角速度为目的,设计了滑模控制器主动控制叉车前后轮转角,并采用切换增益模糊调节法降低系统抖振。仿真结果表明,基于滑模控制的全转向线控三轮叉车同时实现了减小质心侧偏角与跟踪理想横摆角速度的控制目标,提高了叉车的操纵稳定性,并有效减轻了驾驶员的驾驶负担。
[Abstract]:With the rapid development of modern logistics industry, the huge competitive pressure has made the traditional manual handling method unable to obtain the advantage in the transportation efficiency. Therefore, the mechanized handling based on forklift has been attached great importance to by enterprises. At the same time, the introduction of wire steering system has brought new development concept and technological innovation to vehicle steering system, which is suitable for forklift truck with frequent steering, and can solve the disadvantages of traditional steering. Therefore, it is of great theoretical and practical significance to study the wire steering technology of forklift truck. This paper takes the three-wheel steering forklift truck as the research object, aiming at the steering stability and wheel angle tracking problem of the three-wheeled forklift truck. Based on the dynamic model of rear wheel steering of three-wheeled forklift truck and the mathematical model of forklift steering system, the rotation angle of the target rear wheel is obtained based on the ideal variable transmission ratio control strategy with constant yaw angular velocity gain. Considering the constraint information of uncertain parameters, uncertain return moment and disturbance information of road surface in the steering actuator of forklift truck, a sliding mode variable structure angular tracking control strategy is designed. The simulation results show that, Through the combination of the above two control strategies, the sensitivity and stability of forklift steering are improved, and the internal parameter perturbation and external interference of the wire steering system are effectively restrained. In order to improve the steering performance of the traditional rear wheel forklift truck, the two-degree-of-freedom steering dynamics model of the fully steering wire controlled three-wheel forklift truck is studied. Combined with the comprehensive evaluation index of the handling stability of forklift truck and genetic algorithm, the ideal yaw angular velocity gain in the driving process of forklift truck is optimized. The aim is to zero the side deflection angle of the center of mass and track the ideal yaw angular velocity. The sliding mode controller is designed to control the front and rear wheel rotation angle of forklift truck, and the switching gain fuzzy adjustment method is used to reduce the buffeting of the system. The simulation results show that, The full steering wire controlled three-wheel forklift truck based on sliding mode control realizes the control goal of reducing the side deflection angle of mass center and tracking the ideal yaw angle at the same time, improves the handling stability of the forklift truck, and effectively lightens the driver's driving burden.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH242

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