Study Of Transmission And Control System Of Precise Turntable For Rock Mechanics Testing System

In the field of rock mechanics, rock testing machine is essential laboratory equipment. Existing rock mechanics testing machine can only acquire macro mechanics characteristics such as stress-strain behavior by loading, while could not observe the occurrence and development of the internal crack, and liquid and gas vadose in the gaps. In order to visualize the fracture process of rock sample, geologists hope to use a testing machine with rotatable pressure chamber, and high energy accelerator CT imaging and3-d image reconstruction technology, to observe the conditions and characteristics of rock burst, and to provide new basis of underground oil and gas mining, and earthquake research etc. The rotationaccuracy of the rock sample determines the resolution of the image reconstruction, so the accuracy of the rotation is the most important factor for the system design. As the load is heavy and variable, a motor and gearbox has to be used in the driving system. The deformation of the gear teeth during the load variation is non-ignorable.This thesis analyzed the elastic deformation of the gearteeth, and completed finite element simulation by ANSYS software. According to the results of simulation, this thesis discussed the influence of the deformation on the precision of position and speed of turntable. A method to compensate for position error was proposed. The method included compensating in advance in the control system and to improve the speed stability by improving control algorithms. Based on vector control theory, a vector control system model is set up by MATLAB/Simulink. Fuzzy control algorithms were also used for revising the PID controller to improve the system stability. The PID controller and fuzzy controller are used as the speed regulator of vector control system in the simulation. Their characteristics of the dynamics system were simulated and compared.For validating the simulation research results, a model of rotatable rock mechanics testing machine was developed. The model has many functions, such as rotation of pressure chamber, axial loading, confined pressure and seepage load. The measurement and control system of the model was also developed based on Labview. Test results of the model shows that fuzzy control has better dynamic performance than PID control. The research supplies a solid basis for the design of the new testing machine, and provides a new way for precise turntable technology progress.