数字控制电液比例插装流量阀非线性校正方法研究

发布时间：2017-12-31 06:16

本文关键词：数字控制电液比例插装流量阀非线性校正方法研究　出处：《太原理工大学》2015年博士论文　论文类型：学位论文

【摘要】：比例阀通过电信号实现对压力、流量的连续控制,电闭环控制的引入,提高了比例阀控制精度。采用比例阀作为先导级的Valvistor阀,具有结构简单、成本低、通流能力大等优点,其主阀流量输出是先导阀流量的线性放大,在工业领域中应用非常广泛。在实际应用中,比例阀由于比例电磁铁电磁力输出线性度差、位移反馈检测精度不高、阀口台肩加工不对称、比例阀死区较大、负载压差变化等问题,存在较大的非线性,严重的影响比例阀性能。围绕这些非线性问题,从控制电路、信号处理及控制策略等方面进行多层次的非线性校正研究,为提高比例流量阀控制精度提供先进的理论和方法,对推动我国电液比例的技术进步,提升产品的市场竞争力,具有实际的理论意义和经济价值。电液比例控制阀是一个复杂的机电液元件,其驱动控制和调整易受外界干扰和内部特性的耦合影响,尤其是结合了新型数字控制技术的电液比例系统具有了更大的柔性,也增加了系统开发的复杂度。因此本文从传感器反馈检测电路、功率驱动电路、数字式非线性校正、信号处理、压差补偿这几个方面对提高比例流量阀的控制精度开展研究。数字比例控制器的性能直接影响比例阀的输出特性,目前电感位移传感器检测电路检测精度和灵敏度不够高,柔性小,通用性差。本文采用改进型调制解调测量放大电路,搭建测量电路试验台,采用三坐标测量仪进行微小位移检测,试验比对相敏检波电路和改进型调制解调测放电路的静、动态特性,结果表明,改进电路具有灵敏度高、迟滞小、线性度好、动态响应速度快等优点,而且可以同时用于两线圈和三线圈的三线制差动电感传感器检测。为了消除或减小由于线圈放电不完全造成的磁滞,采用改进型h桥反接卸荷功率放大电路来实现线圈电流的快速衰减,并且在电路中设置超快恢复二极管rc缓冲电路来提高电路的稳定性,利用multisim进行功放电路的仿真分析,所设计的功率放大级电路电流纹波小、响应速度快,反接卸荷式极大提高了电流衰减速度。针对比例阀存在的冲击过度、小干扰扰动、零位死区、摩擦滞环以及比例电磁铁存在的非恒力输出、磁滞等问题,采用数字校正方法进行非线性校正,在数字控制器中设置各种软件信号处理模块来解决以上问题,主要包括:斜坡发生器、门槛电压、零位补偿、颤振信号、增益调节、线性度调节等。搭建比例阀数字非线性校正试验台,采用econavant数字采集与信号分析仪进行阀芯位移检测,通过上位机进行参数设置,检测不同参数设置下,阀芯的位移输出特性。试验结果表明,数字控制非线性校正可以改变阀芯的输出特性,从而在实际应用中可以根据负载工况进行参数调整,以达到非线性校正的目的。采用数字式非线性校正提高控制精度,降低了制造成本,且调试方便,通用性强。工业应用中控制精度和抗干扰能力一直制约valvistor插装比例流量阀发展,为了提高其控制精度,实现柔性控制,提出基于偏差判别的控制算法,系统在大偏差、大扰动时,采用模糊pid控制算法提高控制精度和稳定性,开口较小时,采用不完全微分pid控制,避免系统振荡。建立16通径valvistor插装式比例流量阀的稳态、动态数学和仿真模型,对电闭环PID控制下的比例阀进行了稳态、动态及负载特性仿真分析,得到控制参数调整经验值,分析主阀位移和流量输出与先导阀之间的关系。利用Simulink建立先导阀传递函数仿真模型,比较PID控制与偏差判别控制的动态响应特性,检测先导阀的频率响应特性,仿真结果表明偏差判别控制精度更高,稳定性更好,且具有良好的频率响应特性。为了提高插装比例调速阀流量输出的抗负载干扰能力,采用基于先导压差-位移的流量补偿校正,进行理论公式推导,得出压差变化与输入控制电压信号的关系式,建立SimulationX先导阀压差-位移补偿型Valvistor插装比例调速阀的仿真模型,搭建结合dSPACE的半实物仿真试验平台,利用试验台对Valvistor插装流量阀进行静态和动态性能研究,验证模型的正确性,仿真和试验验结果表明通过先导压差-电-位移补偿可以实现对调速阀输出流量的非线性校正,提高流量控制精度,且可以有效的抑制负载阶跃变化时的超调量。
[Abstract]:Through the electrical signal proportional valve for pressure control, continuous flow, introducing the closed-loop control of electricity, improve the control precision of proportional valve. The proportional valve as the pilot valve Valvistor, has the advantages of simple structure, low cost, through the advantages of flow capacity, the main valve pilot valve flow flow output is linear amplification is widely used in industrial fields. In practical applications, due to the electromagnetic force proportional solenoid proportional valve output linearity, displacement feedback detection accuracy is not high, the valve port shoulder processing asymmetry, proportional valve dead zone is large, load pressure changes, there is a big nonlinear, serious influence of proportional valve performance. Around these nonlinear problems, from the control circuit, signal processing and control strategy and other aspects of multi-level nonlinear correction to improve the research, provide the theory and method of advanced control precision proportional flow valve, to promote The electro-hydraulic proportional technology progress in China, enhancing the market competitiveness of products, has real theoretical significance and economic value. The electro-hydraulic proportional control valve is a complex electromechanical components, driving control and adjustment easy coupling affected by external interference and internal characteristics, especially the electro-hydraulic proportional system with digital model control technology has more flexible, also increased the complexity of system development. So this paper from the sensor feedback detection circuit, power driving circuit, digital signal processing, nonlinear correction, differential pressure compensation of these aspects to improve the control precision of the proportional flow control valve is studied. The output characteristics directly affect the performance of digital proportional controller proportional valve, the current detection circuit of inductance displacement sensor detection accuracy and sensitivity is not high enough, flexible small, poor generality. This paper adopts improved amplified modulation measurement Build a test bench circuit, measuring circuit, micro displacement detection using three coordinate measuring instrument, test comparison of phase sensitive detection circuit and improved measuring circuit of modulation and demodulation of the static, dynamic characteristics, the results show that the improved circuit has the advantages of high sensitivity, small hysteresis, good linearity, fast dynamic response speed, but also can for the three wire differential inductance sensor two coil and the three coil detection. In order to eliminate or reduce the coil discharge caused by the incomplete hysteresis, using the improved H bridge anti unloading power amplifying circuit to realize the coil current fast decay, and set the ultra fast recovery diode RC buffer circuit to improve the stability of the circuit in the circuit. Analysis and Simulation of power amplifier circuit based on Multisim, the design of the power amplifier stage circuit of low current ripple, fast response speed, anti unloading greatly improves the current decay According to the existing proportional valve. The impact of excessive interference, small disturbance, zero dead zone, there is friction hysteresis and non constant output proportional solenoid, hysteresis and other issues, using a digital correction method of nonlinear correction, set up a variety of software signal processing module to solve the above problems, in the digital controller including: ramp generator, threshold voltage, zero compensation, flutter signal gain adjustment, linearity adjustment. To build digital proportional valve test bench for nonlinear correction, spool displacement detection using econavant digital acquisition and signal analyzer, set the parameters through the host computer, setting different parameter detection, the output characteristics of the spool displacement. The experimental results show that the nonlinear digital control correction of output characteristics can change the spool, thus in practical application according to adjusting the parameters of load, in order to achieve the nonlinear correction Objective. The digital nonlinear correction to improve the control precision, reduce manufacturing cost, convenient debugging and versatility. The ability to control the precision and anti-jamming in industrial application has been restricted valvistor cartridge proportional flow valve, in order to improve the control accuracy, flexible control, a control algorithm is presented based on the judgement of the deviation, in a large system deviation, large disturbance, the fuzzy PID control algorithm to improve the control precision and stability, the opening is small, the incomplete differential PID control, avoid system oscillation. The steady state established 16 path valvistor cartridge proportional flow valve, dynamic mathematical model and simulation model, the electric closed loop PID under the control of proportional valve steady state, dynamic load characteristics and simulation analysis, control parameter adjustment experience, analysis of the relationship between the main valve and pilot valve displacement and output flow. Using Simulink to establish a pilot valve transfer function The number of simulation model, the dynamic response characteristics of PID control and deviation control discrimination, detection of the pilot valve frequency response characteristics, the simulation results show that the deviation of discrimination of higher control precision, better stability, and has good frequency response characteristics. In order to improve the anti-interference of load plug flow output proportional control valve, the pilot pressure difference flow compensation displacement correction based on theoretical formula, the pressure difference and the relation between the input control voltage signal, a simulation model of SimulationX pilot valve pressure displacement compensation Valvistor cartridge proportional control valve, set up semi physical simulation platform with dSPACE, using a test rig of Valvistor plug flow the valve of the static and dynamic performance study, verify the correctness of the model, simulation and test results show that the pilot pressure electric displacement compensation can be achieved on the speed The nonlinear correction of the valve output flow can improve the flow control precision, and can effectively restrain the overshoot when the load step change is changed.

【学位授予单位】：太原理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH137.52

【参考文献】