Nonlinear friction modeling and adaptive compensation on an inertially stabilized platform system for aerial remote sensing application

To decrease the influences of friction on control precision of a three-axis inertially stabilized platform (ISP) applied in the aerial remote sensing system, an adaptive backstepping control method based on the LuGre model is put forward. According to the characteristics of variable speed values over zero and flatheaded position, the LuGre model of a three-axis ISP is developed and parameters are identified through two-step and dynamic parameter optimization method. Then an adaptive backstepping controller is designed based on the theory of stability. The influences of friction on the precision of ISP's control system are analyzed by Matlab and compared with those of feedforward controller, the validity and robust of the controller are evaluated. Finally, to validate the proposed model and compensation method, the experiments are carried out to the yaw-gimbal system of an ISP. The results show that the adaptive backstepping method can significantly reduce the influences of friction on control precision, by which the fluctuation range error and the root-mean-square error of the angular position are decreased by 78.7% and 91.5% respectively.