The clever chaps at Yale University Grab Labs have developed a robot helicopter integrated with a compliant gripper, able to directly grasp and transport objects while hovering in mid-air outdoors, without need for external motion sensors.
The specially tuned elasticity properties of the gripper allow the aircraft to robustly contact objects, using a stock flight controller without inducing pathological destabilizing effects.
The ability for small robotic aerial vehicles to grasp and manipulate objects around them has numerous applications across a variety of disciplines, including sample retrieval, high-speed courier services, intelligence gathering, and explosives disposal.
This task is very challenging due to the need to precisely position the aircraft over the target object to grasp with a rigid gripper, the coupled mechanics of ground forces and the inherent instability of rotorcrafts, and the presence of aerodynamic disturbances.
Here are two Sample Publications on the topic:
Paul E.I. Pounds, Daniel R. Bersak, and Aaron M. Dollar
Grasping From the Air: Hovering Capture and Load Stability, proceedings of the 2011 IEEE International Conference on Robotics and Automation (ICRA), Shanghai, China, May 9-13, 2011.
Paul E.I. Pounds and Aaron M. Dollar
Hovering Stability of Helicopters with Elastic Constraints, proceedings of the 2010 ASME Dynamics Systems and Control Conference (DSCC 2010).
Source: Yale University Grab Lab