Free-Flying Robot Tested on ESA Parabolic Flights: Simulated Microgravity Tests and Simulator Validation
- Paper number
IAC-07-A2.5.07
- Author
Dr. Silvio Cocuzza, CISAS G. Colombo Center of Studies and Activities for Space, University of Padova, Italy
- Coauthor
Prof. Carlo Menon, Simon Fraser University, Canada
- Coauthor
Prof. Francesco Angrilli, University of Padova, Italy
- Year
2007
- Abstract
Space robotics has an important role in modern space missions. In particular free-flying robots are going to be extensively employed for Extra Vehicular Activities and in Space Servicing missions. Free-flying robots with extended arms can be profitably used for surveillance, inspection, and handling operations. The reproduction of the space microgravity environment for the effective on-ground testing of a 3D free-flying robot is a real challenge. This paper presents the test-bed design and the results of the 2D on-ground testing campaign of a 3D free-flying robot prototype. The 3D free-flying robot prototype has been previously tested in the microgravity environment of ESA parabolic flights. The 3D robot has then been converted in a 2D robot by simply rotating one link taking advantage of the robot modularity. In this way it has been possible to perform planar tests, which have the advantage that the microgravity condition can be simulated without time constraints. Air-bearings on a granite plane have been used to sustain the links weight, and a custom designed dynamometer has been used to measure forces and torques transferred to ground during the arm movement. The 2D test-bed is aimed at a new on-ground testing approach for 3D free-flying robots. First the robot has been tested in a planar manoeuvre by means of an air-bearings table test-bed. Then the data of the 2D tests have been used to validate a full 3D software dynamic simulator. An innovative method to calculate the barycenter position and the barycentric rotational inertia of each link by using ground reaction forces and torques measurements is presented. Once that the barycenter and the barycentric rotational inertia of each link have bed derived, it has been possible to use them in the software simulator in order to verify the matching between the simulated and experimental data. After that the simulator has been fully validated, simulations of any 3D manoeuvre in a microgravity environment can be performed. Other issues which have been assessed by means of the planar tests are the repeatability and accuracy of the end-effector movements, and the verification of the concept that it is possible to minimize base reaction forces and torques by using a redundant manipulator and a special control which takes advantage of it.
- Abstract document
- Manuscript document
IAC-07-A2.5.07.pdf (🔒 authorized access only).
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