基于负载口独立技术的挖掘机回转液压系统特性分析

发布时间：2018-06-06 13:45

本文选题：挖掘机回转液压系统 + 负载口独立控制技术　；参考：《太原科技大学》2017年硕士论文

【摘要】：随着现代液压技术的不断发展,精确控制成为液压技术研究的重点。负载口独立控制技术打破了执行器进、出口耦合控制的约束,可实现对执行器更加精确的控制。本文结合挖掘机回转液压系统的工况特点,研究分析了负载口独立方向阀的动态响应特性,在此基础上建立了基于负载口独立技术挖掘机回转液压系统的控制策略,最终分析其控制效果。本文首先对回转系统目前存在的不足进行了分析。挖掘机回转系统作为最大的惯性负载子系统,在回转过程中存在启动较慢、制动平稳性差的问题,并参阅了大量国内外有关负载口独立控制技术的文献,发现该控制技术的控制理念与回转系统分段控制过程特别吻合。确定了将负载口独立控制技术应用到挖掘机回转液压系统的方案。其次,挖掘机回转运动过程中,对回转平台的运动规律进行了归纳,利用D—H坐标系法对挖掘机回转平台的转动惯量做了理论推导。针对开中心挖掘机液压系统,建立液压动力元件阀控回转马达方块图和动态特性的数学描述,对挖掘机回转液压系统进行理论分析,分析表明回转过程中回转平台启动较慢、制动平稳性差的一个主要原因是:对执行器的进、出油口的控制存在耦合关系。随后,依据基于负载口独立技术挖掘机回转液压系统,建立该系统中主要元件的Simhydraulics仿真模型,其中包括恒功率泵、回转马达、负载口独立方向阀。着重阐述了负载口独立方向阀的结构和原理,根据其结构和原理建立了该阀的数学模型,依据仿真模型对该阀的动态特性进行了仿真分析,分别改变该阀主阀芯质量、主阀弹簧刚度、主阀有效作用面积,分析不同参数对阀动态响应的影响,最终确立主阀的主要参数。最后,根据执行器负载和运行速度方向划分了不同的工作模式,在此基础上将挖掘机回转液压系统归类于阻抗伸出模式并建立了与之相适应的控制策略,即执行器进油口采用计算流量反馈控制策略,出口采用计算压力控制策略。建立Matlab/Simhydraulics仿真模型,并对其进行了仿真分析,结果表明基于负载口独立技术挖掘机回转液压系统能在很大程度上解决回转平台启动慢、制动稳定性差的问题。
[Abstract]:With the development of modern hydraulic technology, precise control has become the focus of hydraulic technology research. The load port independent control technology breaks the constraint of the actuator in and out coupling control and can achieve more accurate control of the actuator. Based on the characteristics of hydraulic rotary hydraulic system of excavator, this paper studies and analyzes the dynamic response characteristics of independent directional valve with load port, and establishes the control strategy of rotary hydraulic system of excavator based on independent technology of load port. Finally, the control effect is analyzed. In this paper, the shortcomings of the rotary system are analyzed. As the largest inertial load subsystem, the rotary system of excavator has the problems of slow starting and poor braking stability in the process of rotation, and reference is made to a large number of literatures on independent control technology of load port at home and abroad. It is found that the control idea of the control technology is in good agreement with the piecewise control process of the rotary system. The scheme of applying independent control technology of load port to rotary hydraulic system of excavator is determined. Secondly, in the process of rotary motion of excavator, the motion law of rotary platform is summarized, and the moment of inertia of rotary platform of excavator is deduced theoretically by using D-H coordinate system method. Aiming at the hydraulic system of open-center excavator, the block diagram and dynamic characteristic of hydraulic power element valve controlled rotary motor are established. The theoretical analysis of hydraulic system of rotary hydraulic system of excavator shows that the rotary platform starts slowly in the process of rotary. One of the main reasons for the poor braking stability is the coupling relationship between the control of the actuator and the oil outlet. Then, according to the rotary hydraulic system of excavator based on the independent technology of load port, the Simhydraulics simulation model of the main components of the system is established, including constant power pump, rotary motor and independent directional valve of load port. The structure and principle of the independent directional valve with load port are expounded emphatically. The mathematical model of the valve is established according to its structure and principle. The dynamic characteristics of the valve are simulated and analyzed according to the simulation model, and the quality of the main valve core is changed respectively. The spring stiffness of the main valve, the effective area of the main valve, and the influence of different parameters on the dynamic response of the valve are analyzed, and the main parameters of the main valve are finally established. Finally, according to the load and speed direction of the actuator, different working modes are divided. On this basis, the rotary hydraulic system of the excavator is classified into the impedance extension mode and the corresponding control strategy is established. That is, the actuator inlet adopts the computational flow feedback control strategy, and the outlet adopts the calculated pressure control strategy. The simulation model of Matlab/Simhydraulics is established and analyzed. The results show that the rotary hydraulic system of excavator based on load port independent technology can solve the problems of slow starting and poor braking stability of rotary platform to a great extent.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU621

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