: Cable robots are a type of parallel manipulators, with this extra specialty that cables work as parallel linkages and multiple motors work as actuators. The distinct difference between cable robots and classic robots is that cable can only tolerate tension. In other word they can only pull objects, it causes that we can't generalize some results of parallel robots for cable robots. But they offer many advantages over conventional serial manipulators. The main benefit of cable robots is their large workspace, which makes them well suited for broadcasting, traorting/loading, and construction application. Unfortunately cable robots' useful workspaces are often unknown or irregularly shaped, so such robots are typically restricted to operate in unnecessarily small, conservatively estimated workspaces. As we mentioned cable robot only can tolerate tension, so all of the points that kinamtically is located in workspace, may not be reached due to negative tension which is practically impossible. It means that we can have different description for cable robot's workspace. In other words requirements of nonnegative cable tensions, as well as maximum admissible tensions, should be satisfied. Cable robots are relatively simple in form, but the traortability and disassembly/reassembly of them are so easy. Also they can provide us high speed. As long as the cables are all in tension, the load is kinematically constrained and the cables resist perturbing forces and moments with equal stiffness to both positive and negative loads. The result is that the suspended load is constrained with a mechanical stiffness determined by the elasticity of the cables, the suspended weight, and the geometry of the mechanism. In this project we have an introduction to cable robots then we studied various kinds of them that have been manufactured so far. Among available robots we chose one that carried a sky camera. Nowadays it uses much more in sport stadiums in order to have images in all angles. In this thesis, control the camera in planar motion and elimination it's vibration in vertical plane is our goal while we consider elastic vibration of cables. We assumed cable as linear springs and also the motion is planar. As we know the elastic vibration of cables includes two parts: longitudinal elastic deflection and transverse elastic deflection. After achieving the motion equation, we find equilibrium points then with linearization of motion equation around equilibrium points we design controller. In each step we simulate the system activity to be assured of controller's performance and finally we introduce the desirable controller. Keywords: 1- cable robots 2- planar motion 3- Workspace 4- Control
