Research And Application Of ADRC Control For An Three-axis Airborne Stabilization Platform

The UAVs generally are small and lightweight,so they are easily interfered with by external airflows and the UAVs themselves are jittering.These disturbances can easily affect the normal operation of an aerial cameras.This paper designs a high-precision three-axis airborne stabilization platform to isolate the aerial camera’s uncertain disturbance,which can keep the camera’s viewing angle stable.This paper analyzes the structural characteristics of the three-axis airborne stabilization platform and its working process.The three-axis airborne stabilization platform is composed of two subsystems: attitude acquisition system and motor drive system.In order to obtain high-precision attitude information,this paper establishes a noise model of MEMS attitude sensor and choose the complementary filtering algorithm to filter out the measurement noise of MEMS sensors.The real attitude angle of the three-axis airborne stabilization platform is sent to the motor drive module through the bus.In order to quickly and accurately eliminate the body jitter,this paper puts forward the active disturbance rejection control(ADRC)algorithm applied to the control system of three-axis airborne stabilization platform and studies the design method of ADRC controller under the control of actuator.This method solves the problem of nonlinear interference of the three-axis airborne stabilization platform.Through the tracking-derivative controller(TD)in the ADRC controller,we can obtain the tracking signal of the position signal and its different order differential signal.In addition to the position signal,we consider the other signals as "sum disturbances" and estimate the "sum disturbance" in real time by extending the state observer(ESO)module and compensate for the "sum disturbance",which improves the robustness and immunity of the system.The nonlinear combination(NLSEF)can select the appropriate controller gain according to the system’s deviation signal.This paper designs the ADRC controller of the three-axis airborne stabilization platform and builds the simulation model of the actuator in Simlink.Comparing the simulation results of the PID controller and ADRC controller,it is proved that the ADRC controller has the advantages of faster tracking speed and stronger anti-interference ability.Finally,we design hardware and software systems of three-axis airborne stabilization platform and build experimental prototype.Through the test ofthree-axis airborne stabilization platform prototype,it can be seen that the shooting screen is clear and clear no obvious jitter.Therefore,the ADRC controller based on the three-axis airborne stabilization platform has obvious stability effect,strong anti-interference ability,high tracking accuracy and it meets the system design requirements.