Backlash nonlinear modeling and compensation of the inertially stabilized platform system for aerial remote sensing application

Aiming at the problems, such as system driving delay, sudden hop in phase changing, shocking vibration, and etc. caused by the backlash nonlinearity in the frame servo system of inertially stabilized platform (ISP) used in aerial remote sensing, the backlash nonlinearity in the frame servo system of ISP used in aerial remote sensing is modeled and compensated. Based on analyzing the characteristics of backlash nonlinearity and transmission, a dead-zone model describing the backlash nonlinearity is established. The influences of backlash impact on system performance are analyzed in simulation using Matlab. Taking the frame servo system as the studying object and using the backstepping integral control method, a controller based on state feedback was designed through successively choosing Lyapunov functions, and experiments were carried out to verify the proposed control method. Experiment results indicate that the system control precision has been effectively improved after compensating the backlash error. Compared with traditional PID control method, the backstepping integral control method obviously deduces the influence of backlash nonlinearity impact on servo system performance. Under given frame expecting angels, compared with PID control method, the backstepping integral control method increases the responding speed by 78.26% and increases the stabilizing accuracy by 23.1%.