| As a kind of equipment that provides stable platform for mission load,gimbal have been widely used in film and television aerial photography,electric power inspection,pesticide spraying,aviation reconnaissance and other fields.The high-precision gimbal can eliminate the disturbance of the carrier,and play an important role in maintaining the stability of the visual axis of the mission load and ensuring the effective operation of the mission load.Therefore,the research on high-precision gimbal technology is of great significance to China's national defense construction and economic development.In this paper,the dynamic equation of the three-axis stablization gimbal system and the mathematical model of the brushless dc motor are established based on the three-axis gimbal system.The controller is designed based on the interval two-mode fuzzy control and sliding mode variable structure control.The performance of the controller is analyzed through C++ simulation.Specific research contents are as follows:1.Set up a three-axis gimbal experimental platform,including mechanical structure,embedded hardware and software platform,and studied the magnetic-directional control method of brushless dc motor and attitude solving algorithm based on gyroscope and accelerometer;2.Conduct structural analysis of the three-axis gimbal experiment platform,establish the coordinate system of inertial space,carrier and each frame rotation system,and establish the mathematical model of gimbal and its executive mechanism according to the principles of Newtonian mechanics and electromagnetism;3.Using the established mathematical model and the established experimental platform,the classical PID control is used for preliminary simulation and testing,so as to verify the availability of the mathematical model and the reliability of the experimental platform;4.Aiming at the interference factors of the uncertainty of the height of the three-axis gimbal and the complex working environment,the relevant theory of sliding mode control was studied,which was introduced into the gimbal control.The simulation analysis of the control system was carried out through C++ software,and the different control effects of the control system and the PID control method were compared.5.Aiming at the chattering phenomenon of sliding mode control,the theory of type-2 fuzzy control is studied,and the interval type 2 fuzzy control is combined with the sliding mode control,and the interval type 2 fuzzy sliding mode controller is designed based on the position loop of the gimbal actuator.Through the simulation experiment,it can be found that compared with the PID control method,the sliding mode control method has better robustness to the external interference.However,its disadvantage is the chattering phenomenon,and the introduction of interval two-type fuzzy control can well suppress the chattering phenomenon of the sliding mode control. |
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