Research On The Control System Of Servo Triaxial Apparatus Based On Quantitative Feedback Theory (QFT)

For now, electro-hydraulic servo technology has been widely used in fields such as aerospace,petrochemical, construction machinery, civil construction and laboratory instruments. Theapplication of electro hydraulic servo technology in the experimental equipment is mainlybecause its small mass per unit of power, fast response speed, load stiffness, high controlprecision. The current testing machine in our country is still in the stage of development, althoughthere have been some achievements. However, due to technology and innovation and other areas,there is still a huge gap between the domestic and foreign in the testing machine industry, the lackof core technology, product stability and reliability which can’t be fundamentally resolved. Thehigh precise instruments still heavily depend on importations. In this paper the design of theTriaxial Instrument use the electro hydraulic servo loading system and quantitative feedback(QFT) as the basis, and then for each system design a QFT controller. Finally the QFT controllersare analyzed the performance in detail.The first chapter explains the basic concept of the Triaxial Instrument. Then discuss the typeand application in the field of civil construction, current research at home and abroad. Discusssuch as the types of soil in the Triaxial Instrument, application in the field of civil constructionand the research status. At last in this paper, the background, the objective and method, presentsituation of studying and applying are introduced.The second chapter designs the mechanical part, electric control system and hydraulic servosystem part, then makes a comparison in the paper for the key element. It describes the design ofthe pressure chamber, the overall layout of the support system part, hydraulic control system andeach module design and selection. According to the actual needs of the servo loading system,control program is ordered.The third chapter explains the electric-servo dynamics modeling system of the TriaxialInstrument including axial and radial control system. Then detailed analyse the mathematicalmodeling of the the Triaxial Instrument. At last use the Bode stability criterion to analyze thesteady state performance of the system by Matlab/Simulink.The fourth chapter: the QFT robust controller is designed for the system of the TriaxialInstrument. At first introduce the basic concepts of the QFT then combine with the actualparameters of each component of the selected system. QFT controllers are designed for eachsystem and discussed the performance in detail.The fifth chapter: Take the servo system of the Triaxial Apparatus as an example. Thedynamic mathematic mode is established by AMESim instead of the traditional mode built by transfer function. And then, they are co-simulated. The co-simulation is closer to the actualsituation, the controller designed by QFT can effectively suppress the parameter perturbation,such as the change of elastic stiffness load, the change of oil effective bulk modulus and thechange of the system friction.This article has laid a good foundation for the manufacturing of the servo Triaxial Apparatus.