Algorithms Development Of Characteristic Test Of Servo-cylinder

Cold Rolling mill hydraulic Automatic Gauge control system (AGC) is a complex electro-hydraulic servo system. The performance of hydraulic cylinder affects the production quality directly. Dynamic characteristics are referring to the responses to the sudden input of the linear systems or components, amplitude and phase bandwidth are often being used. As a key component of the AGC system, the research on the dynamic characteristics test of the servo-cylinder is of significantly important.At present, the method of multi-step and pseudo-random are the most common methods to analysis the dynamic characteristics of the servo-cylinder. However, the weak points of the former are time consuming and complicated programming; The latter algorithm are simple, fast, but slightly week accuracy. Fully using of existing algorithms, and developing the fast algorithms of the dynamic characteristics which can improve the efficiency and accuracy become very important.After a detailed review of the development of the servo-cylinder, the basic principles of the three algorithms are analyzed. The digital simulation of the algorithms are studied under the Matlab environment, and the accuracy, advantages, disadvantages and the major elements which affect the accuracy are also given. The fast algorithm which combing the pseudo-random algorithm with multi-steps algorithm was proposed to test the dynamic characteristics of the servo-cylinder. Based on the digital simulation, NI virtual instrument and equipment are used to test the second-order digital circuit online. A further verification of the efficiency and the accuracy of algorithms is given and theory foundation is made for the experimental study of the hydraulic system.Finally, the fast algorithm which combing the pseudo-random with multi-steps algorithm is used to get the dynamic characteristics of a servo-cylinder. The experimental is complicated on the hydraulic proportional position-control system in our laboratory. According to the test results, the proposed algorithm is reasonable and effective, which can get the exact performance of servo cylinder quickly, and provide a valuable reference for the application of the algorithm in practice.