Research Of A Water-Hydraulic Rotary Servo Valve

The hydraulic drive has a long life, reliable performance and can even speedcontrol without deceleration devices, with unit power, light weight, small size andhigh output power, stable output,etc.. Currently the most widely used hydraulic drive,but there is no pollution due to oil, flammable, explosive, liquid waste treatment costshigher number of serious problems. The water itself clean and flame retardant, just tomeet the security of modern society, the industrial engineering, environment-friendlyrequirements.For bionic robot and underwater-manipulator, the subject puts forward awater-hydraulic rotary servo valve directly driven by a miniature DC motor. Theworking medium of this valve uses water instead of mineral oil. In order to solve thepollution sensitivity and easy blind of the sliding type servo valve, in mode ofmotion,the prototype adopts the rotary motion, and the core and the mouth is usingaxisymmetric decorate, the core of the up and down with water tank are interlinked,reduce the radial and axial unbalance force (the theoretical value to zero), drive toreduce power for purpose, this is and the traditional hydraulic control valvescompletely different.The main task of this paper are: the subject from the Natural Science Foundationof Shandong Province, the main purpose of the water pressure underwater robots androbot R&D miniature DC motor direct drive rotary servo valve, the main tasksinclude the following:1) the characteristics of the water hydraulic technology, applications andResearch on the development of water hydraulic components of the technicalproblems and key technologies, especially the principles of material selection isdifferent from the design and manufacture of hydraulic components. Sliding servovalve, there are many defects, and therefore need to develop a new type of rotaryhydraulic servo valve to solve these problems. 2) developed a rotary hydraulic three four-way servo valve, a full descriptionof this structural design, operating principles and performance characteristics.Miniature DC motor to the valve directly control the rotation of the spool, the spoolrotation angle of the different control valve the size of the empty and the flow of so asto control flow velocity, to control the drive. Miniature DC motor direct drive servovalve, PWM control, improve the control accuracy, stability.3) The rotary hydraulic servo valve static and dynamic characteristics.Nonlinear characteristics such as hysteresis and dead zone, the characteristics of thevalve are present. Pressure dynamic show sometimes a temporary voltage dropphenomenon, which explains the factors of the internal leakage and power limitations.Linear parameters such as flow gain and pressure gain are estimated values. The stepresponse of the dynamic experimental study shows the application of a simple PIDcontroller will be able to reach the valve is fully open state of10ms. In addition, thevalve performance in a2Hz sine wave to determine the operation of the spool positionreference tracking performance.4) mathematical modeling of the rotary pressure hydraulic servo valveaccording to the structure and working principle of the rotary electro-hydraulic servovalve, a mathematical model of the DC motor, transmission and spool valve are amathematical model established and analyzed the composition and influencing factorsof the moment of resistance, determine the equation and transfer function of the valvecontrol system stability analysis, based on mathematical models and transfer functionfor the system simulation studies provide a theoretical basis.5) rotary hydraulic servo valve flow characteristics, including characteristicsof the flow pressure, the fluid dynamic torque characteristics and the jet angle havecarried out a full simulation studies. Fluent software support, the establishment of thedifferent location of the spool model (10), loading1~16Mpa inlet pressure, outletpressure is set to atmospheric pressure, and has been calculated, the flow angle ofrotation with the spool and pressure size under the curve and the same variables liquidMoment value, while the speed of cloud images, the cloud images of the pressurecurve and angle of the jet. By the results of analysis to prove the reliability and practicality of the valve.Future work will include some redesigne of the components in order to reducethe leakage and nonlinear effect, so as to solve the balance problem between theperformance and the practical production.