Performance Optimization of an SMA-Actuated Camera Gimbal

Abstract:
Camera drones use a gimbal to orient the camera in the desired direction and to compensate aircraft movement in flight. The gimbal contributes a significant amount to the weight of the drone. As EU regulations impose limits on the weight of drones, there is a need for novel ways to reduce aircraft weight. Previous work proposed a novel concept for a lightweight SMA-actuated camera gimbal. This study investigates the performance of a first gimbal prototype and ways to improve its shortcomings. The prototype gimbal successfully demon-strated that the requirements regarding angular range and velocity can be met. The weight of the prototype (including camera dummy) was only 2.25 g. However, the stress in the SMA wires was significantly higher than expected, and the 3D printed flexures exhibited issues with high damping, longevity, and buckling. The SMA actuator unit was redesigned by incorporating steel flexures in a pull arrangement. A scaled functional prototype of the actuator unit verified that the above issues are solved, paving the way for a new gimbal prototype at the target size.