四轮转向电动叉车建模与转向稳定性控制研究

发布时间：2019-05-20 13:20

【摘要】：电动叉车是一种常用的实现物料搬运机械化作业的工业车辆,由于其负载比较重,工作空间相对狭小,因此对叉车转向特性的要求要比其他车辆高。四轮转向(4WS)技术是改善叉车操纵稳定性和提高叉车行驶安全性的最有效的主动底盘控制技术。与传统转向系统的叉车相比,四轮转向系统具有转向半径小,操作灵活等特点。而基于线控技术的四轮转向系统,更是取消了传统叉车转向系统中方向盘与转向执行机构之间的机械连接,从而摆脱了机械结构对转向特性的约束,极大地提高了叉车在设计上的灵活性。本文主要研究了经典控制方法下四轮转向叉车操纵稳定性的改善情况。论文的主要研究工作如下:首先,本文结合某公司生产的TFC35型电动叉车,对基于线控转向技术的四轮转向系统的原理和主要组成部分进行了分析与研究。其次,经过力学分析,根据车辆动力学建立了四自由度四轮转向叉车动力学模型。讨论分析了影响叉车操纵稳定性的因素。然后,针对所建立的四自由度四轮转向电动叉车模型,给出了基于粒子群优化PID的四轮转向控制方法,并阐述了针对本文四轮转向系统所设计的粒子群优化PID控制器的具体设计步骤。最后,在Matlab/Simulink平台下,基于本文所建立的四自由度四轮转向叉车模型,分别对前馈型四轮转向控制、传统后轮转向控制和粒子群优化PID四轮转向控制三种控制方法进行仿真试验,通过对比分析仿真结果,表明粒子群优化PID控制四轮转向控制方法的综合控制效果最好,有效地改善了叉车的操纵稳定性。
[Abstract]:Electric forklift is a commonly used industrial vehicle to realize the mechanization of material handling. Because of its heavy load and relatively narrow working space, the steering characteristics of forklift are higher than those of other vehicles. Four-wheel steering (4WS) technology is the most effective active chassis control technology to improve the handling stability and safety of forklift. Compared with the forklift truck of the traditional steering system, the four-wheel steering system has the characteristics of small steering radius and flexible operation. The four-wheel steering system based on wire control technology cancels the mechanical connection between the steering wheel and the steering actuator in the traditional forklift steering system, thus getting rid of the constraint of the mechanical structure on the steering characteristics. The flexibility of forklift design is greatly improved. In this paper, the improvement of handling and stability of four-wheel steering forklift under classical control method is studied. The main research work of this paper is as follows: firstly, combined with the TFC35 electric forklift produced by a company, the principle and main components of the four-wheel steering system based on wire-controlled steering technology are analyzed and studied in this paper. Secondly, according to the vehicle dynamics, the dynamic model of four-degree-of-freedom four-wheel steering forklift is established by mechanical analysis. The factors affecting the handling and stability of forklift are discussed and analyzed. Then, aiming at the four-degree-of-freedom four-wheel steering electric forklift model, a four-wheel steering control method based on particle swarm optimization (PID) is proposed. The design steps of particle swarm optimization PID controller for the four-wheel steering system are described. Finally, on the Matlab/Simulink platform, based on the four-degree-of-freedom four-wheel steering forklift model established in this paper, the feed-forward four-wheel steering control is carried out. The traditional control methods of rear wheel steering control and particle swarm optimization pid four-wheel steering control are simulated. The simulation results show that the integrated control effect of particle swarm optimization PID control four-wheel steering control method is the best. The operation and stability of forklift truck are improved effectively.
【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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