Joint Space Energy Optimization of Tethered Space Robot for End-Effector Optimal Path

Tethered satellites systems have been studied for several decades from which the concept of tether-connected space manipulators developed. The advantages of such robots derive from the extensive reach that can be provided by the tether. This would benefit applications such as satellite repair and space debris removal. 

This thesis first examines the dynamics of a tethered space manipulator as its endeffector traces a prescribed trajectory. The platform, to which the robot arm is attached, is postulated to be much larger than the other components of the system and is specified to follow a circular orbit around Earth. The tether is modelled as a straight rigid rod and the motion of the system is assumed to be restricted to the orbital plane. The tether tension is monitored to ensure that the tether is not subjected to compressive forces.

The system is also studied under torque restrictions; namely, the torques acting on the tether attachment points are set to zero. The possible trajectories traced by the endeffector of this constrained system are investigated. In addition, a method is outlined to determine a feasible end-effector path between two given points while satisfying the zero torque constraint on the tether.

Type: 
Thesis
Date: 
2012 to 2013
Place: 
Department of Mechanical Engineering, Isfahan University of Technology