Arithmetic Investigation Of The Large Telescope Servo Control System Based On The Brushless DC Motor

The large optical telescope is the main facility to observe the goals that in the deep sky. When it is working in a condition such as observing and tracing the sky goals, it is demanded that the servo system should have a very stable tracing speed when it is working at a very low speed and can overcome the low speed jerking motion effectively. So in this thesis, we describe how to design the hardware controller and apply the fuzzy control into the optical telescope.Firstly, we describe the development of the large telescope during the years including the research proceedings both in china and other countries, and also describe the main technologies that affect the working ability of the telescope. At the same time, describing the frame of the control system, appraising the superior quality performance of the brushless DC motor, and deriving its mathematical model; especially aiming at the speed fluctuation problem, analyzing the reason that where the torque ripple come from.Secondly, particularizing the hardware design of the servo system controller, giving the circuit schematic diagram of the function module and describing the working mechanism.Thirdly, fall to resolving the speed ripple and low-speed crawling phenomenon from the standpoint of the software, and also, in order to achieve this point, we apply the fuzzy control which has a good ability in stability, robustness, nonlinearity, to replace the traditional PID controller. Base on this, using the fuzzy math theory and simulating the fuzzy controller to find out which factors are the important ones to affect the control result. So that we can design the fuzzy controller better after analyzing the factors. Physically we could get a better result by using the fuzzy controller.Finally, to realize a fast and high precision tracking controller, improve the speed stability and precision of the fuzzy controller, we pose some methods to improve the fuzzy controller, including the line-interpolation and local integral and so on. By programming them in the servo controller which we have design in a former time, to realize the improved algorithm, after comparing the results of the improved methods, we find that the local integral fuzzy controller could achieve a better result, and satisfy the requirement triumphantly that we have expected.