A vibration suppression for payloads attached to an UAV based on SMA springs

Unmanned Aerial Vehicles (UAVs) have been acquired significant importance in several applications that require the transport of payload and sensors. In this paper, a SMA spring is assumed to represent an elastic attachment between the UAV and its payload. The Sliding Mode Control is used to guide the UAV over the desired trajectory, while the Reduced Dimension Observer technique is used to estimate the payload trajectory due to the lack of sensors. In the presence of the undesired oscillations (caused mainly by maneuvers and external disturbances), the SMA controller is switched on, by altering the dynamics of the spring, and consequently decreasing the transmitted vibration from its payload. Numerical results have shown a positive oscillations suppression based on the change of the SMA temperature.