|Backstepping-Based Control of a Strapdown Boatboard Camera Stabilizer
Peyman Setoodeh, Alireza Khayatian*, and Ebrahim Farjah
International Journal of Control, Automation, and Systems, vol. 5, no. 1, pp.15-23, 2007
Abstract : In surveillance, monitoring, and target tracking operations, high-resolution images should be obtained even if the target is in a far distance. Frequent movements of vehicles such as boats degrade the image quality of onboard camera systems. Therefore, stabilizer mechanisms are required to stabilize the line of sight of boatboard camera systems against boat movements. This paper addresses design and implementation of a strapdown boatboard camera stabilizer. A two degree of freedom (DOF) (pan/tilt) robot performs the stabilization task. The main problem is divided into two subproblems dealing with attitude estimation and attitude control. It is assumed that exact estimate of the boat movement is available from an attitude estimation system. Estimates obtained in this way are carefully transformed to robot coordinate frame to provide desired trajectories, which should be tracked by the robot to compensate for the boat movements. Such a practical robotic system includes actuators with fast dynamics (electrical dynamics) and has more degrees of freedom than control inputs. Backstepping method is employed to deal with this problem by extending the control effectiveness.
Keyword : Attitude control, attitude estimation, backstepping robot control, strapdown inertial navigation system (INS).