| The hydraulic hoist is the specialized hoisting machinery which makes the hydraulic engineering strobe rise and drop. The hydraulic gate hoist is a widely used device in hydroelectricity. The performances of the headstock gear are directly related to the operation of the gate. Regarding engineering safe operation crucial functions, and obtained the more and more widespread application for its unique merit.Electro-hydraulic proportional control system is a hydraulic control system base on technology of proportional control. With the development of electro-hydraulic proportional control technology, it has been playing an important role in the field of hydraulic control. Electro-hydraulic proportional control technology is a feasible and low-price technology whose control precision and response performance can satisfy with the practical requirements in the engineer. It fills up the blank between the technique of the switch-control and servo-control. It is an important branch in the fluid drive and in the control technique. It has a broad prospect in industrial application.It is very common to go on synchronization control in the system of hydraulic transmission. The research of the synchronous control system is having been popular topic at home and abroad. Comparing with others, the hydraulic synchronous control has many advantages, such as simple structure, consitutes convenience, controlled-easily, suited for high power condition etc. Electro-hydraulic proportional control is one of the hottest researching problems at present. It provides biggish meanings in the theory and worthinesses in the application.This paper introduces many hydraulic hoists in common use, and analyzes the main problems at prensent and the whole trend in the development. Through deeply analyzing on the designing demand of the system and making sure each performance which the system must possess, I collect too many kinds of informations. Then I analyze and compare a few electro-hydraulic proportional closed synchronous loop in common use, so design a reasonable hydraulic hoist control system using the electro-hydraulic proportional control technology. And then I build up mathematics model of the nonsymmetry fluid cylinder and the hydraulic synchronous control system, and analyze the static and dynamic characteristics of the system in detail according to the principle of control theory.This paper puts forward that the synchronous control system is not very good at stability and dynamic characteristics, which is only builded up by the electro-hydraulic proportional valves. It should be resolved by enter correction. It is a destination in the original system to increase some devices and components, which is in order to change the structure and function of the system factitiously. This method can resolve the shortage of the system function availably. So the PID correction is joined in the feedback, and a set of excellent parameters of PID controller are confirmed by the means of testing. After applying methods above-mentioned, the various function index of the hydraulic sychronous control system can come to a decent result. Finally, the system is simulated through computer on the basis of the SIMULINK toolbox of MATLAB language, and the results of simulation prove that it is useful to use correction. This paper also summarizes the methods of the problems that how to improve the stability of the system, and how to minish the steady synchronous error, and how to mend the performance standard of the instantaneous response. This course provides a method to design or improve the parameters of hydraulic system. So the paper has certain guiding sense to the design and the use of the similar hydraulic hoist. |
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