文献翻译-对转向装置液压伺服系统的动态仿真

1附录 2DYNAMIC SIMULATION OF THE HYDRAULICSERVO SYSTEM FOR AEG STEERING GEARABSTRACTA dynamic model of a hydraulic servo system for steering gears is developed by means of power bond graphs and then simulated on a computer. Based on the built model comparison is made between different situations with selecting different components and matching them by simulation. The findings presented in this paper are valuable for the system designers andanalysts.KEY WORDS: Components selection and match; Power bond graphs; The hydraulic servo system for AEG steering gearINTRODUCTIONA hydraulic servo system is widely used for steering gears on board ship. It is not sufficient for the designer of a hydraulic system only to know that his proposed system will move the driven load from one state to another and the system is reliable. He should also know how the load will move and if the system response is stable. And further he should know how to select thecomponents and harmoniously match them to reduce the production cost and working energy consumption. This paper will examine a hydraulic servo system in detail by simulation.SYSTEM DESCRIPTIONThe system is illustrated in Fig.1. The system has been employed for the steering gear on the vessel “YU CAI”, which was built in Germany in 1970. The oil supply and its flow through the control valve and the cylinder are shown in Fig.2Fig. 1 The system Fig. 2 Oil flow in the valve and cylinderDYNAMIC MODELLING(1) Power Bond GraphBased on the concept of power flow modeling, and according to the general criteria for 2bond graph structure, the bond graph model for the system is constructed (see Fig. 3). In this structure, valve leakage (from the source port to the exhaust) and cylinder leakage are neglected. Actuator friction Rfa and piston (including the rod) inertia Ia have been lumped with the load (the actuator load being rigidly coupled). The capacitance of the line and the pump have been added to the filter, expressed as Cp.Fig. 3 The bond graphSIMULATIONIn order to solve the model, a program has been developed using ACSL. The fourth order Runge-Kutta integration algorithm has been adopted in the program. With the initial values and coefficients and the input Xv(t) specified, the simulation has been performed on a computer. Fig.4 shows the input Xv(t). Fig. 5 shows the load displacement Xm(t)Fig. 4 The input displacement of the valve spool Fig. 5 The load displacement Xm(t)COMPARISON AND DISCUSSIONOnce the simulation is underway, it is a simple matter to make an excursion, such as Fig.5, to investigate the sensitivity of the system to changes in specific parameters. The dynamic development of all system variables is available. Two methods can be adopted to change one or more parameters and show the timedomain locus of all variables. One is to use the external3runtime commands of ACSL; another is to adopt a loop in the main model program. Adopting the methods above-mentioned, with Vp and Kv changed by means of runtime commands of ACSL, two situations are shown in Fig.6 to Fig.9. Fig.6 and Fig.7 indicate that if the pump and the control valve make a perfect match, that is, Vp and Kv are specified appropriately (the pumpflow rate is slightly more than the rated flow rate of the control valve), then most of the liquid will be pumped to the actuator to do work; However, if the pump and the control valve are unmatched, that is, the pump flow rate is greater than the flow rate that the valve permits toflow through, although the control valve stays open, lots of the liquid will have to be pumped to the oil tank through the relief valve and the consumed energy will turn into heat without doing any useful work. This situation is shown in Fig.8 and Fig.9.Fig. 6 The flowrate into the control Fig. 7 The flowrate through the relief valve supply port valve to tankFig.8 The flowrate into the control Fig.9 The flowrate through the reliefvalve supply port valve to tankCONCLUSIONSThe main components of the system should be well chosen especially the pump and the control valve. Using the model developed in this paper can solve the problem by predicting the results through the simulation. _The model and the methods presented in this paper can be also 4used to study the hydraulic servo systems for steering gear both in system design and dynamic analysis.REFERENCES1 Dang Kun, Power Flow Modeling of the Servo System for AEG Steering Gear, Proceedings of the 3rd Nationwide Chinese Youth Symposium on Mechanical Engineering. Beijing, Mechanical Industry Publisher, 1998,11:135-138 (in Chinese)2 Dang Kun, Yin Fen, Dynamic Simulation of a Hydraulic Pump Sub-system. Journal of Dalian Maritime University 1998, Vol(24)2:105-107(in Chinese)5对转向装置液压伺服系统的动态仿真摘要基于转向装置液压伺服系统的动态模型可通过力的曲线图来建立，然后在计算机上对其仿真。通过对已建立的模型在不同情况下的比较，这种比较是通过选择不同的参数并通过仿真实现的。在纸上的结果对于系统的设计者和分析者来说是有价值的。关键词: 组件的选择和匹配;力学图形；AEG 转向装置的液压伺服系统。1.介绍一个液伺服系统被广泛地应用于板船上的转向装置。对于一个液压系统的设计者来说仅仅知道他提出的系统能够驱动负载从一种状态到达另一种状态或系统是可靠的是不的。他也应该知道怎样选择元件并正确的相互匹配以减少成本并节约能耗。这篇文章将通过仿真详细的介绍液压伺服系统。系统描述系统可由图一描述。这个系统被应用于“YU CAI” 号船上的转向装置，这只船1970年在德国建造。油的供应以及通过控制阀的流动和液压缸由图2所示。Fig. 1 系统 Fig. 2 阀及缸中的油液流动2.动态建模(1) 力学图形基于力流模型的概念，并根据键合图形结构的大体脉络，系统的键合图模型结构如图三所示。在这种结构中，阀的泄漏(从来源埠到尽头)和液压缸泄漏被忽略。 引动器磨擦片和活塞(包括活塞杆)的惯性Ia已经与负载(引动器负荷强行地被加倍)在一起计算。那线路和泵的容量已经被增加到过滤器器,被表示成 Cp.6Fig. 3 键合图3.仿真为了要解决模型, 一个程序用ACSL进行。那第四个命令 Runge-Kutta积分法运算法则已经在程序中被采用。基于初次的数值和系数以及输入Xv(t)是指定的, 仿真已经在计算机上被执行。图4表示输入Xv(t). 图5表演负载位移Xm(t)图 4 管阀的输入位移 图 5 负载位移Xm(t) 4.比较并讨论一经仿真进行,成象是一件十分简单的事情。正如像图5那样，调查在特性参数改变情况下系统的灵敏度。系统改变的动态变化是可以得到的。二个方法能被采用到变更一个或者较多的参数而且显示出所有变数的时间轨迹。一个将使用外部的运行时间 ACSL 的指令;另外的将在主要的样板程序中采用一个回路。 采用上述提到的方法,通过运行时间ACSL指令改变Vp和Kv，在图6到图9中二个情况被显示。图6和图7表明如果泵和控制阀做一个完全的匹配,也就是说Vp 和Kv恰当地被描述(泵的流量略多于控制阀的额定流量),然后大部份的液体