Over the past four years, researchers at McGill University have developed a novel concept for studying dynamics and control of robotic grasping of objects in space. This problem arises in several applications - those currently under investigation include on-orbit servicing of satellites and removal of space debris. The main difficulty in experimental testing of such tasks is how to emulate the gravity-free environment of space here on the ground. A number of experimental facilities have been developed around the world to emulate the gravity-free conditions for space robotics research. For example, one popular approach involves floating the system under investigation - a robotic arm or a mock-up satellite - on air-bearings on a glass-covered or granite table [1-3]. A few research establishments have invested in neutral buoyancy water tanks for three-dimensional, high-fidelity, albeit very costly, emulation of weightlessness [4]. We have proposed a novel idea which involves using a small helium blimp to emulate a free-floating object. Although not perfect, this concept is simpler, less expensive to implement and is more suitable for 3D emulation of the gravity-free conditions of space. An experimental facility has been developed in the Aerospace Mechatronics Laboratory to implement this concept in an indoor laboratory setting [5-7]. The main components of our facility are: a six-degree-of-freedom robotic manipulator placed on a 3m linear track, a spherical helium airship 6 ft in diameter, made neutrally buoyant and balanced, a Vicon six-camera system and associated control hardware and software interfaces. This video submission focuses on the control of the airship for satellite emulation.
