This video shows simulations and experiments on the control of a quadrotor aerial robot equipped with a rigid or an elastic-joint arm
See  for the paper describing the method used in the following video.
- , “Aerial Robots with Rigid/Elastic-joint Arms: Single-joint Controllability Study and Preliminary Experiments”, in 2016 IEEE/RSJ Int. Conf. on Intelligent Robots and System, Daejeon, South Korea, 2016, pp. 1667-1672.