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Predictive visual servoing for robotic capturing and stabilizing uncooperative tumbling space objects


On-orbit servicing using a space manipulator has been proposed by several national and international government agencies and commercial bodies for repairing, rescuing, refueling and removal of defunct satellites. A similar concept is envisioned for all robotic servicing missions and entails a robotic arm capturing a target satellite in a safe and secure manner given several operational and environmental constraints. Target satellites have often tumbling motion, resulting in increased complexity of robotic capturing operation. Robotic capturing of a tumbling target has not been attempted yet, though several missions for free-flying capture using a robotic arm on-orbit have so far been demonstrated.

Figure 1


The technology

The Canadian Space Agency's (CSA) invention is an algorithm providing optimal control and estimation theory for planning the motion of a robotic manipulator to intercept a tumbling, non-cooperative target satellite with unknown dynamics. The unknown dynamics are obtained from a laser camera system enabling the robot to intercept the target at an optimal rendezvous. An optimal rendezvous ensures optimal alignment for robotic grasping such that the robot's grapple and the target's grapple fixture arrive at the rendezvous point simultaneously at the same velocity and proper respective angle. Furthermore, once the parameters have been established, grappling can be achieved "blind", meaning it is possible without additional assistance from the laser camera system. After grasping, the robot brings the grasped target to rest as quickly as possible subject to the constraint that the force/moment interactions between the robot and the object do not exceed their limits.

Commercial potential

The business opportunity

The CSA's invention provides the opportunity to service a potentially larger number of recipient targets (e.g. free flyer and tumbling capture). This invention is complimentary to existing servicer technologies and given the invention's successful demonstration is more likely to encourage further development funding from interested parties (e.g. NASA and DARPA). The invention could be immediately tailored for the Phoenix project developed by DARPA, especially in relation to the servicer capturing the Payload Orbital Delivery System (PODS), NASA Asteroid Redirect Mission (ARM), Automated Rendezvous & Docking (AR&D) in space, orbital debris removal, servicing/rescuing failed satellites or providing continued support for an antenna "farm".

Development status

Ground-based testing has been successfully completed and recorded. Additional in-person viewing can be made possible through visitation to the CSA.

Commercialization status

The CSA is seeking preferred private Canadian partners who are interested in licensing the intellectual property or collaboratively exploring further applications of the technology.

Technology transfer details

A commercialization license for this technology is available.

The business opportunity may be referred to by its CSA case number: 51107



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