水液压旋转式伺服阀研究

发布时间：2018-05-10 15:00

本文选题：水压传动技术 + 水压旋转式伺服阀　；参考：《中国海洋大学》2012年硕士论文

【摘要】：液压传动具有功率密度大、输出力/力矩大、调速方便、工作平稳、冲击小、快速启动/制动/换向、过载保护等优点，在仿生机器人领域越来越受到重视。然而，由于油液存在污染、易燃、易爆、废液处理成本高等一系列严重问题，使得油压驱动的仿生机器人的安全性受到质疑，工作环境受到制约。水压驱动是以纯水作为工作介质来实现能量传递和控制的驱动方式，它具有油压驱动的一切优点，同时克服了油压驱动的缺陷，能大幅提高仿生机器人的性能。液压伺服阀是仿生机器人的关键部件，控制着其执行机构的位置及速度。本研究针对仿生机器人和水下机械手，提出研发一微型直流电机直接驱动的旋转式水压伺服阀。该阀以纯水（包括自来水和海水）代替矿物油作为工作介质解决了矿物油所带来的污染、易燃、易爆、工作场所肮脏等缺点，同时提高了仿生机器人的性能如：响应速度、效率、控制精度等。在运动方式上，该阀采用旋转的运动方式代替传统的滑动，解决了滑动式的伺服阀对污染敏感、易于卡死等问题，，且阀芯及阀口均采用轴对称布置，阀芯上下端都与水箱相通，减小径向和轴向不平衡力(理论值为零)，达到降低所需驱动功率目的，这些与传统液压控制阀完全不同的。采用微型直流电机可以实现PWM控制，提高了控制的精度、稳定性等。本文主要的研究任务是：课题来源于山东省自然科学基金项目，主要研究目的是为水下机器人和机械手研发一微型直流电机直接驱动的水压旋转式伺服阀，主要工作包括以下内容： 1）研究了纯水液压技术的特点、应用及研究现状，阐述了研制水液压元件存在的技术难题和关键技术，特别是材料选择的原则不同于油压元件的设计制造。滑动式伺服阀存在诸多缺陷，因此需要研发新型的旋转式水压伺服阀来解决这些问题。 2）研发出旋转式水压三位四通伺服阀，本文对其结构设计、工作原理以及性能特点做了充分的描述。该阀采用微型直流电机直接控制阀芯的旋转，阀芯旋转角度的不同控制着阀空的大小以及流向，从而控制流量流速，达到控制驱动器的目的。采用微型直流电机直接驱动伺服阀，可以实现PWM控制，提高了控制的精度、稳定性。 3）研究了旋转式水压伺服阀的静动态特性。非线性特性比如滞后现象以及死区，在阀的特征中都有存在。压力动态显示出了有时短暂的压降现象，这说明了内部泄漏和电源的局限性的因素。线性参数如流量增益和压力增益也都是估计的值。动态试验研究的阶跃响应显示了，应用一个简单的PID控制器在10毫秒时就能达到阀门全开的状态。此外，阀在一个2Hz正弦波确定阀芯位置的操作上表现出很好的参考跟踪性能。 4）对旋转式水压电液伺服阀进行数学建模，根据旋转式电液伺服阀的结构及工作原理，建立数学模型，并分析了阻力矩的组成和影响因素，确定了该阀控制的系统方程和传递函数根据数学模型和传递函数进行系统稳定性分析，为系统仿真研究提供理论基础。 5）研究了旋转式水压伺服阀的流场特性，包括对流量压力特性、液动力矩特性以及射流角都进行了充分的仿真研究。通过Fluent软件的支持，建立不同阀芯位置的模型（共10个），加载1~16Mpa的入口压力，出口的压力设为大气压，然后进行计算，得到流量随阀芯旋转角度和压力大小的变化曲线以及相同变量下的液动力矩值，同时得到速度云图、压力云图以及射流角的变化曲线。通过结果分析证明了该阀的可靠性和实用性。未来的工作将包括一些部件的重新设计，以降低泄漏和非线性效应，从而解决阀的性能和实际生产之间的平衡问题。
[Abstract]:The hydraulic transmission has the advantages of large power density, large output force / torque, convenient speed regulation, smooth work, small impact, quick start / brake / reversing, overload protection and so on. It has been paid more and more attention in the field of bionic robot. However, because of the pollution, flammable, explosive, and high cost of waste liquid treatment, the oil pressure is driven by oil. The safety of the bionic robot is questioned, and the working environment is restricted. The hydraulic drive is a driving mode that uses pure water as the working medium to realize energy transfer and control. It has all the advantages of the oil pressure drive and overcomes the defects of the oil pressure driven. It can greatly improve the performance of the bionic robot.
The hydraulic servo valve is the key component of the bionic robot, which controls the position and speed of its actuator. In this study, a rotating water pressure servo valve was developed for a bionic robot and underwater manipulator, which was directly driven by a micro direct current motor. The valve was solved with pure water (including tap water and sea water) instead of mineral oil as a working medium. The pollution, flammable, explosive, and dirty work places brought by mineral oil, as well as the performance of the bionic robot, such as response speed, efficiency, control precision, etc. in the mode of motion, the valve adopts a rotating motion mode instead of the traditional sliding, and solves the problem that the sliding servo valve is sensitive to pollution, and is easy to die, and the valve is easy to die. Both the core and the valve port are arranged in axis symmetry, the upper and lower ends of the valve core are connected with the water tank, reducing the diameter direction and the axial unbalance force (the theoretical value is zero) to reduce the required driving power. These are completely different from the traditional hydraulic control valves. The use of micro DC motor can realize PWM control, and improve the precision and stability of the control.
The main research task of this paper is: the project is derived from the Shandong Natural Science Foundation project. The main purpose of this study is to develop a water pressure rotating servo valve directly driven by a micro DC motor for underwater robot and manipulator. The main work includes the following contents:
1) the characteristics, application and research status of pure water hydraulic technology are studied. The technical problems and key technologies for the development of water hydraulic components are expounded, especially the principle of material selection is different from the design and manufacture of oil pressure components. There are many defects in the sliding servo valve. Therefore, a new type of rotating hydraulic servo valve needs to be developed to solve these problems. Problem.
2) a rotating hydraulic pressure three position four pass servo valve is developed. This paper describes its structure design, working principle and performance characteristics. The valve uses micro DC motor to control the rotation of the valve core directly, the valve core rotation angle is different to control the size and flow direction of the valve air, thus controlling the flow velocity and achieving the control of the driver's order. By using micro DC motor to drive servo valve directly, PWM control can be realized, and the accuracy and stability of control can be improved.
3) the static and dynamic characteristics of the rotating hydraulic servo valve are studied. The nonlinear characteristics such as hysteresis and dead zone are present in the characteristics of the valve. The pressure dynamic shows the sometimes transient pressure drop, which illustrates the internal leakage and the limitation of the power supply. The linear parameter, such as the flow gain and the pressure gain, is also estimated. The step response of the dynamic test study shows that the application of a simple PID controller can achieve full opening of the valve in 10 milliseconds. In addition, the valve shows good reference tracking performance on the operation of a 2Hz sine wave to determine the valve core position.
4) the mathematical modeling of the rotary hydraulic hydraulic servo valve is carried out. According to the structure and working principle of the rotating electro-hydraulic servo valve, a mathematical model is set up. The composition and influence factors of the resistance moment are analyzed. The system equation and transfer function of the valve control are determined according to the mathematical model and transfer function to analyze the system stability, which is imitated for the system. True research provides a theoretical basis.
5) the flow field characteristics of the rotating hydraulic servo valve are studied, including the flow pressure characteristic, the hydraulic torque characteristic and the jet angle. Through the support of the Fluent software, the model of the different valve core position (10) is set up, the entrance pressure of the 1~16Mpa is loaded, the pressure of the outlet is set to the atmospheric pressure, then the calculation is carried out. The variation curve of the flow rate with the rotating angle and pressure of the valve core and the moment of the hydrodynamic force under the same variable are obtained. At the same time, the velocity cloud, pressure cloud and the change curve of the jet angle are obtained. The reliability and practicability of the valve are proved by the analysis of the results.
Future work will include redesign of some components to reduce leakage and nonlinear effects, so as to solve the balance between valve performance and actual production.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH137.52

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