| There are extremely rich biological resources and mineral resources in the ocean,but the marine development environment is harsh and requires the use of underwater robots or manipulators for development.When hydraulically driven underwater manipulators are used in deep-sea environments,they will face problems such as complex system structure and interpenetration of oil and water,and the use of seawater hydraulic drive will solve these problems.At present,the underwater manipulator is generally controlled by a proportional servo system.In response to the urgent need for the control components of the deep-sea hydraulically driven precision operating system,this article is based on the deep-sea hydraulic proportional control valve,and compares the marine adaptive structure and control of the proportional directional valve.The optimization method of the scheme and the performance migration characteristics in the deep sea environment have been studied,and the development and testing of the prototype have been completed.The main research contents of the paper are as follows:(1)In view of the special working conditions of the deep sea,the structure of the rotary proportional directional valve is determined,and the leakage of the proportional directional valve and the problem of sea depth pressure are solved by means of end sealing and oil filling compensation.At the same time,a mathematical model of the rotary proportional directional valve with multiple parameters such as ocean depth and medium viscosity is established.The effect of different control methods on the static and dynamic performance of the proportional directional valve is studied through numerical calculation.The simulation results show that the use of three closed-loop control makes the proportional The tracking performance of the output signal of the reversing valve is enhanced.(2)The performance migration characteristics of the rotary proportional directional valve in the deep sea environment are studied.Through numerical calculation,it is found that the use of seawater as the working medium improves the stability of the proportional directional valve.The finite element simulation results show that compared with the traditional proportional directional valve,the invented end-sealed rotary proportional directional valve solves the problems of deformation and jam caused by deep sea pressure,but the rotor of the oil-filled motor rotates in the compensation oil.Incoming viscous losses will reduce the effective power of the motor.Therefore,the influence of different compensation media and sea depth on the viscous loss was further studied.The simulation results showed that as the medium viscosity,motor speed and sea depth pressure increase,the viscous loss continues to increase.Finally,No.10 aviation hydraulic oil is used as compensation.Medium,compared with No.46 hydraulic oil,the viscous loss of the motor is reduced by about 50%;(3)Through the static and dynamic characteristics test,the various performances of the rotary proportional directional valve are studied.The test results show that the rotary proportional directional valve can achieve zero leakage,the dead zone is about 7.33%,the maximum working flow at 15 MPa is 6 L/min,the flow has a certain non-linearity,and the step response rise time is 0.1 s.In the case of 5% output amplitude,the amplitude bandwidth is 30 Hz,and in the case of 100% output amplitude,the amplitude bandwidth is 6 Hz.Finally,the developed proportional reversing valve is applied to the spiral swing cylinder control system of the elbow joint of the underwater manipulator.The swing cylinder runs smoothly and the control accuracy of the system can reach ±0.1°.The 6500 m deep sea working condition simulation test has been carried out,and the proportional valve has good control performance,which provides the core control element for the deep sea hydraulically driven precision operation control system. |
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