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

Section: 
Research
Subsection: 
Thesis
Place: 
Department of Mechanical Engineering
Isfahan University of Technology (IUT)
Isfahan (Iran)
Associate: 
A. Nasr
M. Keshmiri
Date: 
2013/01/22 to 2013/09/21

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

On this project, first, the dynamics of a tethered space manipulator as its end-effector traces a prescribed trajectory should be check. The platform, which the robot arm is attached, is postulated to be 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. Furthermore, the tether tension is monitored to make sure 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 end-effector of this constrained system are investigated. In addition, a method is outlined to figure a possible end-effector path between two given points while satisfying the zero torque constraint on the tether.

Task:

  • Forward Kinematics, Workspace and Dynamic Modelling and Analysis a 4 dof Robot which is Connected to Space Shuttle
  • The main purpose of this project was to examine the planar kinematics and dynamics of a space robot tethered to an orbiting platform

  • Proposing a Nonlinear Control Algorithm of Redundant Robot Vibration by Just Changing in Cable Length

  • The model employed assumed that the tether is straight and rigid and that the center of mass of the system is coincident with that of the platform and traces a circular orbit around earth