双吊点启闭机液压系统动态特性研究

发布时间：2018-12-14 13:50

【摘要】：无论是水利枢纽、航运船闸、电站、防洪涝都要用到闸门,而闸门的开启和关闭都要用到专用的机械装置——启闭机。与体积庞大笨重的相同容量的卷扬式启闭机相比较,液压式启闭机的自重轻得多,而且水工结构布置简单,可以节省大量投资,尤其是当孔口数量较多时此优点更为显著。由于运行平稳,系统可方便地实现无级调速,能自动实现过载保护,易于与计算机连接,实现智能化控制等,液压式启闭机显示出了其明显的优越性。但是,液压启闭机作为闸门启闭主要发展方向的同时,也面临着系统动态性能不理想、系统同步精度不高、平衡回路稳定性差等等亟需解决的诸多问题。因此,本文从问题出发,采用一种新型的同步回路结构,完成控制策略的设计并改善了系统的动态性能以及平衡回路的稳定性,为启闭机液压系统今后的发展提供参考。首先,简述启闭机液压系统的工作原理、研究现状、面临的主要问题,阐述论文的研究背景和意义。第2章,详细阐述了系统关键元件A11VO比例变量泵以及FD型单向节流式平衡阀的工作原理。基于传递函数法分别建立了上述两个关键元件的数学模型,得出方框图,并推导出开环传递函数。就关键元件的主要结构参数变化分析其对系统动态特性的影响。根据推导出的开环增益,提出改善系统稳定性的可行方法。第3章,对液压系统仿真软件AMESim做了简要介绍。利用HCD库分别建立了同步回路和平衡回路中的两个核心元件:A11VO比例变量泵以及FD型单向节流式平衡阀的仿真模型。验证了模型的准确性,得出抑制比例泵出口的压力冲击,稳定压力,提高系统的稳定性以及加快平衡回路系统的调节时间的方法。第4章,详细介绍了PID控制算法各环节的作用以及参数整定方法。搭建了启闭机液压系统的AMESim仿真模型。结合系统模型进行了PID控制器的设计。在系统中引入PID控制器后,重点针对系统在阶跃偏载和1缸阶跃速度下比例泵控同步缸能否完成较为精确的位移跟随进行仿真。观察PID控制器的控制效果和动态性能。第5章,介绍了前馈补偿控制器的工作原理,针对负载扰动的情况下,PID控制器的控制效果并不是十分的理想这一问题,通过前馈补偿控制策略来消除负载变化给系统带来的扰动。建立启闭机液压系统同步回路模块的传递函数方框图,在系统中引入前馈补偿环节,并设计了前馈补偿控制器。仿真结果表明,在相同偏载力干扰下,前馈PID控制较单纯PID控制的抑制干扰能力有了明显的改善。
[Abstract]:No matter it is a water conservancy project, a shipping lock, a power station, or a flood control station, it is necessary to use the gate, and the opening and closing of the gate must use a special mechanical device, the hoist. Compared with the large bulky hoisting hoist of the same capacity, the hydraulic hoist has much lighter weight, and the hydraulic structure is simple, which can save a lot of investment, especially when the number of orifices is more than that of the hydraulic hoist. Because of the smooth running, the system can realize stepless speed regulation conveniently, can realize the overload protection automatically, easy to connect with the computer, and realize the intelligent control, etc., the hydraulic hoist has shown its obvious superiority. However, as the main development direction of gate hoist, hydraulic hoist also faces many problems that need to be solved urgently, such as system dynamic performance is not ideal, system synchronization accuracy is not high, balance loop stability is poor, and so on. Therefore, starting from the problem, this paper adopts a new synchronous loop structure to complete the design of the control strategy and improve the dynamic performance of the system and the stability of the balance loop, which provides a reference for the future development of the hoist hydraulic system. Firstly, the working principle, research status and main problems of hydraulic system of hoist are briefly introduced, and the research background and significance of this paper are expounded. In chapter 2, the working principle of A11VO proportional variable pump and FD type unidirectional throttle balancing valve is described in detail. Based on the transfer function method, the mathematical models of the two key components are established, the block diagram is obtained, and the open loop transfer function is derived. The influence of the main structural parameters of the key components on the dynamic characteristics of the system is analyzed. According to the derived open loop gain, a feasible method to improve the stability of the system is proposed. In chapter 3, the hydraulic system simulation software AMESim is introduced briefly. The simulation models of A11VO proportional variable pump and FD type unidirectional throttle balancing valve are established by using HCD library. The accuracy of the model is verified, and the methods to suppress the pressure shock at the outlet of the proportional pump, to stabilize the pressure, to improve the stability of the system and to speed up the adjusting time of the balance loop system are obtained. In chapter 4, the function of PID control algorithm and the method of parameter tuning are introduced in detail. The AMESim simulation model of hoist hydraulic system is built. The PID controller is designed based on the system model. After the introduction of PID controller in the system, the simulation is focused on whether the proportional pump controlled synchronous cylinder can complete the more accurate displacement following under the step bias load and the step speed of 1 cylinder. Observe the control effect and dynamic performance of PID controller. In chapter 5, the working principle of feedforward compensation controller is introduced. In the case of load disturbance, the control effect of PID controller is not very ideal. The disturbance caused by load change is eliminated by feedforward compensation control strategy. The transfer function block diagram of synchronous loop module of hoist hydraulic system is established, feedforward compensation link is introduced into the system, and feedforward compensation controller is designed. The simulation results show that the performance of feedforward PID control is significantly improved than that of simple PID control under the same bias force interference.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TH137

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