Development Of Electrical Torque Loading System And Research On Its Control Technology

The higher motility and reliability are required for the aircrafts with the rapiddevelopment of aerospace industry, and the experiment test is an important element in thedetection of aircraft performances. Electrical torque loading system (ETLS) is one of theimportant equipments in the aircraft ground half hardware-in-path simulation system, whoseperformance requirements are increasingly improved, thus it is significant and worthy toresearch the control technology of ETLS.The research status on the domestic and foreign of torque loading systems and theircontrol technologies is introduced in the paper, the achievements about the torque loadingsystems and their main control methods are comprehensively summarized by the deepanalysis and research on it, and all of these lay a solid foundation for the development ofETLS and research on its control technology in the paper.In order to research its control technology, an ETLS is developed in the paper. The ETLSstructure composition and working principle are deeply analyzed, and the paper designs itsgeneral scheme according to its functional requirements. Then the hardware system is dividedinto different functional modules on the basis of general scheme of the ETLS, which aredesigned with the principle of high-precision and high-reliability. The methods includingphotoelectricity isolation and shielding etc are adopted to improve the anti-disturbancecapability of the ETLS. Through the analysis of functional requirements of the ETLS, thesoftware system of the ETLS is developed on the basis of the modular design idea inLabVIEW, and it is divided to different modules, whose primary functions are specified,meanwhile the flow charts are provided.The paper chooses respectively loaded system and the ETLS as research objects, theirmathematic models are built respectively with physical modeling method. According toanalyze the interactional relationship between loaded system and the ETLS, the ETLSmathematic model is built, which takes the loaded system characteristics into account. In thetwo cases, namely whether it takes the loaded characteristics into consideration or not, thetransfer functions of forward path and surplus force path of the ETLS are constructedrespectively and analyzed comparatively. According to the transfer function of its forward path and surplus force path, the paper analyzes the stability of the ETLS and the effect that thechange of torsional stiffness would have on the characteristic of its forward path and surplusforce path using Bode diagram At last the paper concludes the characteristics of surplus force,which provides theoretical foundation for the research on the method of restraining surplusforce.Based on the characteristic analysis of the ETLS, the control technology of its torquetracking is researched in the paper. Being aimed at the problem of its closed-loop stability, thepaper adopts torque derivative negative feedback method to improve its closed-loop stability,which is validated by simulation. Meanwhile the PID control method is adopted to improveits dynamic performance, responding rapidity and accuracy, which is validated by simulation.Being aimed at the problem of surplus force, the angular velocity feedforward compensationelement of the ETLS is designed with structure invariance principle, which is validated bysimulation. Based on the above method, the paper does research on the compound controlmethod based on the PID controller, the effectiveness of that is validated by simulation andprototype experiments, and the results obtained from simulation and prototype experimentsare analyzed comparatively.ETLS is a passive torque servo system with high-accuracy, strong-coupling andparameter time-varying characteristics, due to the parameter of PID controller cannot beadjusted on-line, which leads to the controller cannot adapt to system parameter variance.Being aimed at the above problem, the paper adopted fuzzy adaptive PID control method.Based on the PID controller, the paper uses two-dimension fuzzy controller to build fuzzyadaptive PID controller with the theory of fuzzy control. From the view of the capacities ofrestraining surplus force and tracking torque, the effectiveness of fuzzy adaptive PID controlmethod is validated by simulations. According to comparative analysis, the results show fuzzyadaptive PID control method can obtain higher regulating precision, faster response speed andmore effective capacity of restraining surplus force than PID control method.