Double-Motor Gear Transmission System Investigation Used On The Large Telescope

With the development of technology and human endless enthusiasm for the exploration of the universe, the tools for understanding the universe are also constantly in progress. As the important tool of the astronomical telescope that has from the meter level in1970’s development to the10meters or even tens of meters now. The research contents of this paper belongs to the subsystem of the international cooperation project (TMT), the mainly responsible of CIOMP is researching tertiary mirror system of TMT. The research is the tertiary mirror azimuth axis system drive. Shaft driving mode of the worldwide large telescope mainly have worm drive, friction drive, gear drive, direct drive mode and so on. Through the analysis of the TMT tertiary mirror system volume and weight requirements, this paper determines to use the gear transmission system for the shaft drive control.Firstly, the paper analyzed the work process of tertiary mirror system.According to control precision and control time requirements of tertiary mirror azimuth axis control system, we should analysis the control system to provide the control parameters. According to each part of the parameters of the azimuth axis control system to select each part of control system, then build the entire control system.Secondly, solved a very important question in double-motor synchronized driving system. This problem is the motor output speed is equal. When we should select the actual motor, even if select the same type of motor that the motor’s parameters can not be exactly the same. This different can case the differential oscillation phenomenon, will seriously affect the control accuracy of the system. Using the two motor speed difference as a feedback and PI control algorithm. They can be a very good solution to the problem of inconsistent motor speed, make the two motor synchronous.Once again, based on the double-motor synchronous linkage, using torque bias eliminate gear clearance influence on control system. In the Simulink software established the tertiary mirror system modeling with gear gap. Through simulation test for the model can clearly see that joining the torque bias can be very good for eliminating gear clearance influence on the control accuracy. In the process of the simulation proved that the torque bias is effectively.Finally, completed the control system hardware circuit design. This board carried on the functional verification and is proved that can be fully competent in the gear transmission system of double-motor control. This board is designed rich communication interface circuit and a LCD. These functions can be very good to complete data community with other system and also can display real-time control information. The circuit board can be very good to complete subsequent control experiment.