Dynamic modeling and nonlinear decoupling control of inertial stabilized platform for aerial remote sensing system

The mutual coupling between the motion of three frames exists when inertial stabilized platform (ISP) for aerial remote sensing system is working, due to the mechanical character of the stabilized platform. Based on Lagrange mechanics and starting from analytical mechanics, a kinetics model of inertial stabilized platform is developed for analyzing the complex coupling relation. On the basis of the model, a nonlinear decoupling control method using sliding mode control (SMC) is designed for rolling and pitching frames after coupling moment being taken for external disturbance. While, for azimuth frame, which can not directly adopt sliding mode control method, a novel method of introducing a judgment factor and combining SMC and PID is provided. Compared with PID method, the simulation results show that the overshoot of the system is reduced obviously and the decoupling effect is better. Results obtained will be a theoretical foundation for the further study of inertial stabilized platform, and guarantee high precision to stabilized platform system.