锻造油压机开式泵控液压系统研究

发布时间：2018-04-09 18:18

本文选题：锻造油压机　切入点：开式泵控系统　出处：《燕山大学》2016年博士论文

【摘要】：锻造行业中所消耗的巨大能源以及它向大气中排放的污染物,一直都是我国工业发展过程所必须解决的问题和难题,也是想要实现工业可持续发展的前提条件。与比例阀控系统、闭式泵控系统、直驱式容积控制电液伺服系统相比,开式泵控锻造油压机液压控制系统可以降低装机功率、减小冷却补油系统和简化系统结构,能够明显提升节能效果,并且保留了传统系统响应快、精度高、稳定性强的优势。对于锻造行业来说,研究开式泵控锻造油压机液压控制系统的容积控制特性具有重要的理论意义,在自由锻、模锻、多向模锻等设备中应用开式泵控锻造油压机液压控制系统具有积极的现实意义。锻造油压机负载和工艺条件具有时变性和随机性,故要求液压控制系统在不同负载与工艺条件下都具有良好的控制特性。本文以开式泵控锻造油压机系统为研究对象,采用理论分析和实验研究相结合的方法,以比例变量径向柱塞泵特性、油压机系统特性和锻件负载时变特性为基础,针对开式泵控锻造油压机系统卸压冲击抑制、负载容腔独立控制、管路系统动态特性控制进行研究,分析系统控制方法及响应特性。对开式泵控锻造油压机系统卸压冲击问题进行研究,建立按能量规律和流量规律卸压的卸压曲线数学模型,分析不同卸压曲线在不同卸压阶段的特性。基于不同阶段对压力下降梯度的不同需求,提出开式泵控锻造油压机组合式卸压曲线,规划变量泵偏心量,实现系统平稳卸压。对开式泵控锻造油压机系统负载容腔独立控制问题进行研究。建立主缸位置与回程缸压力复合控制的负载容腔独立控制模型,分析主缸系统与回程缸系统耦合作用对活动横梁位置控制精度的影响,提出前馈负载同步补偿解耦控制方法,提升系统快锻位置控制精度。对开式泵控锻造油压机系统管路系统动态特性控制问题进行研究。建立包含管路的油压机系统模型,分析系统的频域特性,提出基于流量压力复合控制的前馈补偿控制方法,综合锻件负载特性,实现对管路系统快锻过程带载时压力上升慢导致压下量不足的改善。通过0.6MN锻造油压机实验平台实验验证提出的组合式卸压曲线卸压控制方法、基于前馈同步补偿解耦控制的负载容腔独立控制方法、基于流量压力复合控制的管路系统动态特性控制方法的有效性。
[Abstract]:The huge energy consumed in the forging industry and the pollutants it emits into the atmosphere have always been the problems and problems that must be solved in the process of industrial development in our country, and are also the preconditions to realize the sustainable development of industry.Compared with proportional valve control system, closed pump control system and direct-drive volume control electro-hydraulic servo system, the open pump controlled forging press hydraulic control system can reduce the loading power, reduce cooling and oil filling system and simplify the system structure.It can obviously improve the effect of energy saving, and retain the advantages of fast response, high precision and strong stability of traditional system.For the forging industry, it is of great theoretical significance to study the volume control characteristics of hydraulic control system of open pump controlled forging hydraulic press.The application of hydraulic control system of open pump controlled forging press in multi-directional die forging equipment has positive practical significance.The load and process conditions of forging hydraulic press are time-varying and random, so the hydraulic control system is required to have good control characteristics under different load and process conditions.In this paper, the open pump controlled forging hydraulic press system is taken as the research object. The method of combining theoretical analysis with experimental research is adopted, and the characteristics of proportional variable radial piston pump, hydraulic press system and forging load time-varying characteristic are taken as the basis.In this paper, the control methods and response characteristics of open pump controlled forging hydraulic press system are studied, including the suppression of pressure relief impact, the independent control of load cavity and the dynamic characteristic control of pipeline system.In this paper, the pressure relief impact problem of open pump controlled forging hydraulic press system is studied, and the mathematical model of pressure relief curve is established according to the law of energy and flow, and the characteristics of different pressure relief curves in different pressure relief stages are analyzed.Based on the different demands of pressure descending gradient in different stages, the combined pressure relief curve of open pump-controlled forging press is proposed, and the eccentricity of variable pump is planned to realize the steady pressure relief of the system.The independent control of open pump-controlled forging press system is studied.An independent control model of load cavity for compound control of main cylinder position and return cylinder pressure is established. The influence of coupling action between main cylinder system and return cylinder system on the accuracy of position control of moving beam is analyzed. A decoupling control method for synchronous compensation of feedforward load is proposed.Raise the precision of position control for fast forging of the system.The dynamic characteristic control of pipeline system of open pump controlled forging press system is studied.The hydraulic press system model including pipeline is established, and the frequency domain characteristic of the system is analyzed. A feedforward compensation control method based on flow-pressure compound control is proposed to synthesize the forgings' load characteristics.The pressure rising slowly during the rapid forging process of pipeline system leads to the improvement of insufficient reduction.The combined pressure relief control method is verified by the experiment platform of 0.6MN forging oil press, and the load cavity independent control method based on feedforward synchronous compensation decoupling control is presented.The effectiveness of dynamic characteristic control method for pipeline system based on flow and pressure compound control.
【学位授予单位】：燕山大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG315.4

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