BACKSTEPPING-BASED CONTROL OF A STRAPDOWN BOATBOARD CAMERA STABILIZER

As a boat is easy to shake with waves, a stabilizer is required to stabilize the line of sight of a boatboard camera against boat movements. Especially in surveillance, monitoring, and target tracking operations, high stabilizing performance is needed to obtain a high-resolution image even if the target is in the far distance. This paper addresses design and implementation of a strapdown boatboard camera stabilizer. A two degree of freedom (yaw/pitch) robot performs the stabilization task. The main problem is divided into two subproblems dealing with attitude estimation and attitude control. A sophisticated data fusion algorithm based on an extended Kalman filter (EKF) fuses strapdown rate gyro measurements with measurements of some drift free aiding sensors and gives accurate estimates of boat movements. Estimates obtained in this way provide trajectories, which should be tracked by the robot to compensate boat movements. Such a practical robotic system includes actuators with fastdynamics (electrical dynamics) so it has more degrees of freedom than control inputs. Backstepping design will be employed to deal with this problem in order to extend the control effectiveness of the system

Keywords:

Attitude Control , Attitude Estimation , Backstepping , Data Fusion , Extended Kalman Filter (EKF) , Robot , Strapdown Inertial Navigation System (INS