The Development Of A Novel Electric Hydraulic Loading Device

Ship shafting force loading system is developed to simulate vibration characteristics,stress distribution and size of the thrust bearing stress of the ship shaft system under different conditions and predictive study on the ship shafting experimental apparatus under laboratory conditions,which is of great significance to shorten the development time,save research funding and improve equipment reliability.In this paper,a ship shafting force loading project as the engineering background,based on principle of Pascal has developed a new type of dynamic force loading device.Specific research contents are as follows.Firstly,based on the analysis of force loading tracking control the research status at home and abroad,a novel plan is proposed which is by squeezing the closed container to realize force loading.The scheme based on and the characteristics of the inverse association between pressure changes and airtight liquid volume change,the high pressure is formed by pushing the electric cylinder piston to extrude the Pressure cylinder,so as to realize the pressure control of large scale and high precision.The force loading system mathematical model is completely deduced,the existed nonlinear and uncertain link in the system is analyzed,which simplified system model.Afterwards,the cascade control theory is introduced to construct a double closed-loop control system.According to the dynamic characteristics of system,the electric cylinder speed inner ring and pressure control outer ring of the double closed loop PID controller are designed.Digital simulation is carried out by MATLAB software,the existed bounded uncertain parameters influence on the stability of the system frequency domain are analyzed in this paper,the method of contrast is adopted to evaluate the influence of key parameters,such as bulk modulus and loaded quality on the pressure tracking precision.Finally,the dynamic force loading system is described which divided into three parts:the mechanical system,the hydraulic loading system and the PAC control system,the function and principle of each part are analyzed.According to the functional requirements and technical indicators,the corresponding hardware design and type selection are completed.The design of control software of the force loading device and its development environment is introduced in this paper,the overall system the loading tests are done andthe experiment results are analyzed,which demonstrate that the loading device has a good dynamic force loading capacity.This article research results have been used in practical applications and achieved good performance.The control method which used to improve the performance of dynamic force loading and the conclusion in this paper are also beneficial to the other force loading systems,which also has a certain reference significance and guiding engineering practical value to the design of other kinds of experiment facilities.