Control architecture for a UAV-mounted pan/tilt/roll camera gimbal

This paper presents the architecture of a pan/tilt/roll camera control system implemented on the Georgia Tech's UAV research helicopter, the GTMax. The controller has currently three operating modes available: it can keep the camera at a fined angle with respect to the helicopter, make the camera point In the direction of the helicopter velocity vector, or track a specific location. The camera is mounted in a large, but relatively light gimbal. Each axis is driven by a modified servo, and optical encoders measure the gimbal orientation. A PID controller with anti-windup and derivative filtering was designed in Simulink based on simple models of the servos and later implemented on the real system. A discussion of results obtained from Hardware-In-The-Loop tests and fliglit tests is given at the end of the paper.