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Ongoing Research Project

Ongoing and future projects are described. Potential graduate, undergraduate USRA and honours thesis students should contact Professor Sharf.

* Small Unmanned Aerial Vehicles: dynamics, control, motion planning, design, maneuverability * Robotic Grasping of Objects in Space * Dynamics and Control of Legged Vehicles * Development of Autonomous Helium Balloon for Indoor Surveillance

Research area 1: Small Unmanned Aerial Vehicles:

Description of this area is under construction.

Research area 2: Robotic Grasping of Objects in Space

Research in this area involves theoretical, numerical and experimental work. In particular, we are investigating a range of problems associated with autonomous robotic capture of free-flying tumbling objects in space. Applications envisioned involve removal of space debris and on-orbit servicing and repair of satellites and spacecraft. The problems addressed include: development of optimal algorithms to intercept a moving and tumbling target; development of control strategies for gripping the object and for post-capture stabilization of the whole system.

The methods developed are implemented and tested on the robot-airship facility designed specifically for studying this problem (see Laboratory Facilities for details). The unique aspect of our experimental facility is a novel concept for emulating the weightless environment of space here on the ground. This facility comprises: a six degree-of-freedom robot on a track; a 6-ft spherical indoor helium balloon; a Vicon motion capture system; and a dedicated real-time system for controlling the robot and the balloon. Because of its neutral buoyancy, the balloon will be used to emulate a free-flying object while the robot attempts to capture it. This facility allows us to imitate robot-object interactions that occur in space, thereby providing a unique testing ground for space robotic operations. The ultimate objective is to develop and validate an intelligent system that would enable autonomous operations of space manipulators for tasks involving interactions with free-flying objects.

Research area 3: Dynamics and Control of Legged Vehicles

Research is currently ongoing with two hybrid wheeled/legged platforms: PAW quadrupedal robot developed at McGill and the Micro Hydraulics Toolkit (MHT) developed by DRDC---Suffield. For PAW, we are developing a gamut of new quasi-static and dynamic behaviours, in particular, jumping and obstacle climbing, rolling and wheeled-to-legged transition behaviours. This work involves analysis, simulation and implementation on the real platform. For the 12 degree-of-freedom MHT robot, we are developing coordinated control strategies to allow the robot to optimally configure itself during rolling modes of locomotion. At this stage, the work is purely analysis and simulation, but implementation on the actual platform is planned for the future.

Research area 4: Development of Autonomous Helium Balloon for Indoor Surveillance

Our long-term objective is to develop an autonomous helium balloon for indoor surveillance and presence. This work is driven by recent technology developments and increased interest in application of unmanned aerial vehicles. In particular, fast miniaturisation of sensing, actuation and power-generation devices has opened unprecedented opportunities for further progress in the development of small-scale autonomous vehicles. Our vehicle of choice for indoor environments is a small (~7ft) helium balloon because balloons are inherently stable, safe and relatively inexpensive. Balloons offer significant advantages over wheeled/tracked robotic devices because they are unaffected by stairs and can negotiate the relatively unobstructed environment that usually exists in the middle altitude of a room. Their height also makes them a better platform for onboard cameras.

Initial work on this project has involved retrofitting a commercial radio-controlled balloon from Mobile Airships with on-board sonar rangers and a wireless transmitter.

Commercial interface to the balloon has also been replaced with a computer Labview interface. A detailed description of our results to date can be found on Publications).

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