| Inclining hydraulic cylinder is widely used in areas such as aerospace, engineering machinery and so on. It generally has the following characteristics: having continuous change of gravity component along the direction of hydraulic cylinder; component of gravity changes in range. Direct-drive servo control system has the dual advantages of AC servo motor's flexibility and hydraulic's large output, having been applicated in the device of many areas and achieved great economic efficiency.This article designs a kind of Direct Drive Volume Control (DDVC) servo system is generally applicable to Inclining hydraulic cylinder aim at characteristics of the Inclining hydraulic cylinder, the drive system dynamically balance the changing force by setting accumulator's pressure, and retrieve energy when the hydraulic cylinder retracts, Significant energy savings; The displacement ratio of double-pump and the effective area ratio match strictly, which make the positive and negative characteristics of the pump-controlled asymmetric cylinder similar and improve the control performance; The use of hydraulic accumulators makes exits and entrances of double-pump keeping high pressure, and make up the oil quickly, so improves the system's response speed and bandwidth.The control characteristic of hydraulic cylinder definitively impact on the performance parameters of products, and DDVC servo system has so many advantages, so combining the two, the principle analysis and experimental research of direct drive inclining hydraulic cylinder are theoretically analysed and experimentally studied in article, which has important theoretical significance and practical value of Promoting our aviation and engineering machinery products.After synthesizing numerously literatures at home and abroad, this paper compares the characteristics between DDVC system and conventional hydraulic control system, and reviews current trend of research on DDVC electro-hydraulic servo technology firstly. Secondly, the article analysis the theory of DDVC electro-hydraulic servo systems, outlines the overview of the bucket wheel stacker reclaimer selected for the study and analysis the force when bucket wheel stacker/reclaimed works under three different conditions; Design a direct-drive hydraulic system and complete the analysis and calculation of the hydraulic circuit; The main components the prototype are integrated in the valve block, so that the system structure was greatly simplified; and integrated valve blocks, gear pumps, accumulators, tanks and other related connecting parts such as couplings, pipes are assembled in the hydraulic package.Lastly, it builds system model of AC servo motor and pump-controlled cylinder subsystem, and then discusses parameters'impact on system performance, carries out computer simulation and conducts an experiment on the test stand. In virtue of Bode plot, the paper analyzes the performance of the system. |
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