【作者】 许小庆；

【导师】 权龙；

【作者基本信息】 太原理工大学 ， 机械电子工程， 2010， 博士

【摘要】 伺服比例元件(包括伺服比例阀和伺服比例泵)是重要的液压控制元件,广泛应用于工业自动化和工程自动化领域的各个方面,能否掌握与其相关的技术,对我国国防建设、装备制造业具有重大影响。目前该技术是制约我国从制造大国向制造强国转变的重要因素,国家中长期发展规划、重大专项调整规划均列为重点突破的难点。而伺服比例元件的性能在很大程度上决定于其电-机械转换器的性能,因此深入研究电-机械转换器对我国装备制造业和国防建设具有重要意义。论文作为国家自然基金“新概念电液流量、方向连续控制的理论与方法研究”(50575156)研究内容之一,在低成本、高响应、新结构电-机械转换器等方面进行了深入研究。论文首先对比例电磁铁进行了理论分析,为了同时利用有限元分析方法的准确性优点和多种仿真软件的快速性分析的优点,建立了比例电磁铁关键磁阻的有限元分析模型,利用有限元分析方法得到了模型磁阻的特性参数,通过拟合有限元计算结果,得到了比例电磁铁关键磁阻的计算公式,利用Simulink和Ansoft验证了公式的正确性。为在仿真软件中准确建立比例电磁铁的模型奠定了基础。提出了利用开关电磁铁构成单电磁铁式电液伺服比例阀的方案。在闭环控制基础上,提出自适应前馈补偿方法,补偿了开关电磁铁的非线性特性;采用抗饱和积分控制方法,在消除稳态误差的基础上,减小了电磁铁动态响应时间。理论上解释了两种方法的原理,试验验证了两种控制方法的效果。另外,利用铁心速度反馈,增大闭环回路增益,进一步减小了电磁铁的动态响应时间。研究表明,与现有技术采用比例电磁铁相比,新方案具有设计简单、成本低的优点。为研制用于驱动大流量电液伺服比例阀先导级的高响应电–机械转换器,提出采用异型永久磁铁励磁的动圈式直线电机结构方案,给出了设计准则,采用有限元计算方法分析磁路特性,计算结果表明,采用异型永久磁铁较规则形状可提高驱动力7%以上。在此基础上,设计了驱动大流量电液伺服比例阀先导级的动圈式直线电机,并制造出样机,建立了测试系统,对样机的动静态特性进行试验测试,试验结果验证了设计计算的正确性,试验结果表明研制的样机性能可以满足高响应大流量电液伺服比例阀先导级驱动要求。为满足电液伺服比例阀对电–机械转换器高响应速度的要求,提出一种新的具有2个运动构件的2自由度电–机械转换器。解释了此种电–机械转换器缩短电液伺服比例阀动态响应时间的机理,给出了多种物理可行的结构形式,对单输入双输出电-机械转换器的磁路进行了分析,结果表明,这种转换器可同时驱动比例阀的阀芯和阀套,达到控制阀的开口量的目的,但不能独立控制阀芯或阀套。对混合式双输入2自由度电–机械转换器的磁路进行了分析,应用有限元方法研究了其多种工况下的输出特性。结果表明,新的2自由度电–机械转换器可同时控制2个直线移动部件,使它们同向或反向运动,并可用于电液伺服比例阀以及其他需要双直线位移输出元件的控制。针对电液位置伺服系统起动过程会造成系统压力突降和执行器运动速度大幅波动,产生液压冲击;当系统有多个执行器工作时,系统压力突降会导致其他执行器产生误动作,甚至发生安全事故。论文提出两种解决方法。一是将位置控制过程分解为速度和位置两个控制过程,且执行器的最大速度由系统最大流量和液体的压缩性限制。二是利用阀口压差对伺服阀流量进行修正。阐述了两种方法的原理,采用数字仿真和试验进行了验证,表明在不影响系统响应特性的前提下,两种方法可以有效消除电液位置伺服系统起动过程中的系统压力突降和产生的冲击。更多还原

【Abstract】 Servo proportional components (including servo proportional valves and servo proportional pumps) are important hydraulic control components and widely used in every aspect of industrial and engineering automation. The ability to master the associated technology has a significant impact on national defense construction and equipment manufacturing. Currently, the technology is a holding back factor for our country to transform from a big manufacturing country to a manufacturing power. National long-term development plan, major projects are planning to adjust this technology as a key breakthrough. As the servo proportional component performance is largely determined by the electrical-mechanical transformer performance, it has great significance for us to be in-depth study of electrical-mechanical transformer for national defense and equipment manufacturing industry. Being one aspect of the study of National Natural Science Foundation " Theories and Methods of New Concept Continuous Control on Electro-hydraulic Flow Rate and Direction " (50575156), this thesis focus on in-depth study of low-cost, high response, new structure of electrical- mechanical transformer and research methods for electrical-mechanical transformer. Proportional solenoids were researched theoretically. In order to take the advantage of high accuracy of finite element method (FEM) and advantage of rapid calculation ability of most simulation software, the FEM model of the key reluctance in proportional solenoid was established. Characteristic parameters of the FEM model were determined with FEM. By fitting the FEM calculation results, the formulas for calculating the key reluctance in proportional solenoid were obtained. The formulas were also validated with Simulation in MATLAB/SIMULINK and FEM software Ansoft. This work laid the foundation for building the accurately proportional solenoid model in simulation software.A new scheme for electro-hydraulic proportional servo valves with on-off solenoids was proposed. A method of adaptive Feed Forward Compensator (AFFC) to correct static nonlinear characteristic of on-off solenoids is proposed based on close loop control. The settle time is shorten obviously by using Anti-Satuation Integral Control (ASIC) techniques, while the static error is held to zero. The principles of AFFC and ASIC are explained theoretically and tested in experiments. Moreover, we found that the transient time was even shorten when the gain of the close feedback loop was increased in our scheme, The research results show that our scheme has the advantages of simply design and low price.In order to develop the fast response electro-mechanical transformer used to drive the pilot stage of large flow rate servo proportional valve, a novel structure of electro-mechanical transformer with shaped permanent magnet was proposed and its design principles were indicated. Magnetic circuit characteristics of the dedicated moving coil linear motor (MCLA) were studied with finite element method. The analysis indicated that MCLA’s driving force can be increased more than 7% by using shaped permanent magnet. A MCLA used to drive the pilot stage of large flow rate servo proportional valve was designed and the prototype was developed. The test system for small linear motor was built and the prototype was tested. The test results show that the performance of the prototype can meet the pilot driving requirement of fast response large flow rate servo proportional valve.A novel 2-degree-of-freedom electro-mechanical transformer (2-DOF EM) with two moving parts was proposed to meet the high speed response of electro-mechanical trans- former required by servo proportional valves. The principle on which it decreased the response time of a servo proportional valve was explained. Several possible structures were introduced. The magnetic circuit of single-input dual-output EM (SIDO EM) was analyzed. Analysis indicated that SIDO EM can simultaneously drive the proportional valve spool and valve cover, and the valve opening is controlled. But the spool or valve cover cannot be controlled independently with SISO EM. The magnetic circuit of a hybrid two-input 2-DOF EM was analyzed, and its output characteristics in every case were derived with finite element method (FEM). Research results indicate that the 2-DOF EM can control the two linear moving parts simultaneously, drive them to move in the same or opposite direction independently. It can be used in the control of servo proportional valves and other equipments which have two linear moving parts.The application of proportional servo valve was studied. The starting of electro-hydraulic position servo system might cause the drop of the system pressure, actuator velocity fluctuation and hydraulic impact. The sudden drop of the pressure, if with more than one actuator in the system, would probably misact other actuators or even lead to grave accidents. Facing the problems, two solutions are proposed. One is to divide the position control procedure into a position control procedure and a velocity control procedure in which the maximum velocity of the actuator is restricted within the supply flow rate and the liquid compressibility. The other is to adjust the flow rate at the servo valve by means of pressure difference of the chambers. These two methods are demonstrated theoretically and verified by digital simulation and experiments of an electro-hydraulic position servo system. It is finally proven that the sudden drop of the supply pressure and hydraulic impact during the starting of electro-hydraulic position servo system can be removed with the two new methods without influence upon the system response properties.更多还原