【作者】 陈彬；

【导师】 易孟林；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2007， 博士

【摘要】 随着造船技术的发展,船舶日益趋向大型化、高速化,船舶液压舵机由电液伺服调节器进行控制,要求调节器稳定性、可靠性和动态性能好。电液伺服调节器是一个电液伺服系统,当伺服阀进行启闭动作时,系统内产生的水击经过管路的传输,在活塞端引起较大的振动幅值,容易产生跑舵现象。液压水击现象是系统的非恒定流动,是流动参数阶跃变化时的动态过渡过程,特别是电液伺服调节器的阀芯、阀套为互动关系,对水击的影响更加复杂。本文以REG260型调节器为例,对电液伺服调节器的水击诱发振动机理和特性及其相关因素的影响规律进行深入的研究,以便采取相应的控制措施来减小或抑制水击振动,保障系统有较好的动态性能。首先对电液伺服调节器的静动态特性进行了分析,利用对称阀控非对称缸的理论,定义了系统的负载流量和压力,考虑对称阀存在零位间隙和泄漏,建立了系统的数学模型,进行仿真,得到系统的稳定性能、阶跃响应和跟踪性能指标。然后考虑油液与结构耦合作用,对激振源――反馈阀套式伺服阀的耦合水击振动特性进行研究,利用油液粘度较大的瞬变流摩阻模型,推导了完备的伺服阀耦合水击运动微分方程,运用特征线法获得了系统激振力的特性;对刚性管路以及动边界液压缸,采用拉格朗日网格法处理动边界条件,进行活塞端的水击传输特性频域的计算分析,表明忽略动边界对管路系统的影响会造成很大的误差,在动边界条件下,泊松耦合的对水击压力幅值的影响不明显,连接耦合在伺服阀开启较快时,管路中水击效应明显;伺服阀开启较慢时,管路轴向振动以应力波频率振动的受迫振动占主导地位,水击振动中高频成分增加;伺服阀启闭动作结束后,活塞端仍有较大的压力振动幅值。伺服阀的启闭规律对水击振动的影响比较显著,根据调节器的水击耦合振动方程,运用非线性规划算法,得到系统耦合水击振动的优化伺服阀启闭规律曲线。在此规律作用下计算得到水击压力衰减率近似达7dB;从实际工程应用出发,对优化启闭规律采用两阶段、三阶段线性化处理,水击压力下降率可达18.2%;采用自适应神经模糊推理方法控制优化启闭动作,取得了较好的效果。根据调节器的水击振动响应计算结果,从调整系统阻抗和减小激振源影响两个方面进行了振动控制研究。结果表明,调整管路长度是从频域分析避开谐振频率点的简单有效的方法,将REG260型电液伺服调节器的管长改进为0.73m,压力振动衰减率可达6dB;根据负载阻抗、活塞面积以及容腔初始长度等参数的影响规律,应用非线性规划方法优化了结构参数,调整了系统的阻抗,压力振动衰减率近似可达6dB,有效的减小了水击压力幅值。最后通过REG260型电液伺服调节器的实验,对其静动态以及水击耦合振动特性进行了实验研究,表明利用对称阀控非对称缸理论所建立的数学模型,可以有效的进行系统的稳定性判别以及输入信号与输出位移的关系研究;利用耦合水击振动模型在伺服阀控制口水击压力振动的计算结果与实验测试值偏差为2.87%,实验得到的液压缸无杆腔压力变化趋势与计算结果基本一致,验证了耦合振动模型的正确性;运用伺服阀的两阶段启闭规律,测得活塞无杆腔的压力下降了13.04%,验证了控制措施的有效性。更多还原

【Abstract】 Along with the development of shipbuilding, ship the growing tendency of large, high-speed, steering the movement controlled by electro-hydraulic servo control regulator, so the regulator required stability, reliability and easy to control. REG260 type of electro-hydraulic servo steering regulator system is a typical electro-hydraulic servo system, servo valve open-shut moves, oil within the system have been rapid alternating movements of the pressure wave process is water hammer, flowed in the transmission line, it cought be cause the larger vibration amplitude in piston area, deviate the mandate direction of the rudder, the ship sailed to the security threat. Hydraulic water hammer phenomenon is the unsteady flow; flow parameters vary is the dynamic changes in the transition process. In particular, it is interaction between valve spool, valve sleeve of electro-hydraulic servo system regulator, the system of water hammer effects more complicated in the pipeline network. It is necessary to research the servo system of water-induced vibration mechanism and the characteristics and the law related to the influence of factors deeply, in order to take appropriate control measures to reduce or suppress the vibration of water hammer, to protect the safety of the system operation.First, the electro-hydraulic servo steering Regulator REG260 for static and dynamic characteristics were analyzed for symmetric asymmetric cylinder valve control theory, redefines the load flow and pressure, and consider the existence of symmetric zero valve clearance and leaked to establish a system of model. Simulations show that the system is stable and has good step response and tracking performance.Then, account structure coupled with the oil, the vibrate source -- the servo valve coupled vibration of water hammer is studied, whereas viscosity of hydraulic system is the larger transient flow model, the proposed model is a complete servo valve coupled differential equations of motion of water hammer. Use the method of characteristics derived characteristics of vibration force of the water hammer; laid the study foundation of pipeline transmission characteristics and control; In numerical calculation using Lagrangian grid handling moving boundary conditions. Frequency - domain analysis shows that neglected the impact of moving boundary condition, the error will be great with the boundary changes; Since moving boundary conditions, for junction coupling, when the servo valve opened quickly, pipeline water hammer effect obviously, on the contrary, servo valve opened slowly, pipeline to axial vibration frequency vibration stress wave dominated, the bigger frequency composition of water hammer vibration increases. There is still a larger vibration amplitud after servo valve open-shut moves; Servo valve open-shut law of the water hammer effects were more marked, under the system vibration coupling water hammer equation, using of nonlinear programming algorithm, by the study of water hammer process, the optimal curve law coupling water hammer calculation wree derived, the optimization law of water hammer pressure decay rate of approximately 7dB. From a practical application, for the optimization using the law includes a two-stage and three-stage linear, the rate of pressure decline is 18.2% and using adaptive neuro-fuzzy logic control, and achieved good results.According to water hammer vibration response calculation results of the analysis, vibration controls of REG260 the servo system wree proposed from two aspects of the adjustment of system impedance and reduce the vibration source. The results show that the adjustment of the length of pipe from the frequency domain analysis may avoid resonant frequency of pipe, it is simple and effective method to improve the management of long to 0.73 m, pressure vibration attenuation rate should be 6dB; Load impedance of the piston area and the capacity cavity length of the initial parameters to be improved, application of nonlinear programming method for the optimization of system impedance, the optimization of the structure parameters, adjusted the system impedance, effectively reduced the amplitude of water hammer pressure, the pressure vibration attenuation approximate rate of up to 6 dB.Finally, adoption of REG260 electro-hydraulic servo steering regulator experiments, studied its static and dynamic characteristics and the water hammar coupling vibration characteristics, the experiments showed that the use of symmetric asymmetric cylinder valve control theory established by the mathematical model can be effective for system stability discrimination, and relationship of input drift the output displacement signal analysis; consider oil and structure coupling model, through the pressure oscillation experiment of the servo valve port and calculation results deviation is 2.87%; and the hydraulic cylinder with a rear-chamber pressure trend consistent with the calculation results, verified coupling vibration model is correctness; the use of servo valve open-shut law two stages of testing rear-chamber pressure is 13.04% decline, proved the control measures is effectiveness.更多还原