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Application Of Variable Universe Fuzzy Control In Linear Motor Control System

Posted on:2015-05-14Degree:MasterType:Thesis
Country:ChinaCandidate:W T FuFull Text:PDF
GTID:2272330473950368Subject:Mechanical engineering
Abstract/Summary:PDF Full Text Request
As the main development direction of modern manufacturing technology, high speed and high precision machining demand high requirements of the transmission and control of CNC machine. In the way of “zero transmission”, linear motors can overcome the shortcomings of traditional feeding systems, such as low control accuracy,small acceleration and so on. Therefore, linear motors satisfy the machining requirements of modern manufacturing. However, the direct drive method also increases the difficulty of motor control. This paper is based on the linear motor feed system of high speed CNC machine as the research object, according to the characteristics of the direct drive method, the fuzzy control system of permanent magnet linear synchronous motor(PMLSM) is designed by means of combining fuzzy control and other control strategy. On this basis, through the introduction of variable universe fuzzy control method, a further improvement of the servo system is made. The main work and contributions of this paper are as follows:1. After the research of the working principle of PMLSM, its mathematical model is established under the dq coordinate system. The field oriented vector control technology combined with PID control, PMLSM servo control system model is established. The analyses of the advantages and disadvantages of traditional control method provide a basis for the further research.2. PMLSM has nonlinear, time-varying and strong coupling characteristics, using the traditional control methods are difficult to get good control effect. By taking advantage of the universal approximation property of fuzzy control system and combining the 0du ? control(direct voltage control) method, a fuzzy control system of PMLSMs is established. Compared with the PID control system, the fuzzy servo system is more simplified. It can not only achieve fast track control of the speed, but also have good anti- interference ability and robust performance.3. Due to the fuzzy control have such problems as low control precision, big steady-state error and so on. By introducing variable universe fuzzy control method, the control precision can be improved without changing the fuzzy control rules. In order to keep the servo system model as simple as possible, a single input single output fuzzy controller is used to obtain the input domain scaling factor and do not transform theoutput domain. Because of the using of 0du ? control method, the servo system lacks excitation current control link. By introducing 0di ? control method, the servo system is improved. In this way this paper not only achieves high precision speed control but also realizes the decoupling control of excitation current and thrust current. The simulation results show that the designed variable fuzzy control system has strong adaptive ability and robustness.
Keywords/Search Tags:PMLSM, fuzzy control, variable universe fuzzy control, direct voltage control, scaling factor
PDF Full Text Request
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