Cablerobot

Cable-driven parallel robots (CDPR) are a type of parallel robot in which flexible cables serve as actuators. Synchronized winding of the cables on several winches enables the end-effector to be controlled precisely and with high repeatability. The simple design ensures that cable robots are relatively cheap to manufacture and allows a good ratio between weight and payload. Their low inertia allows high accelerations and speeds of several meters per second. In addition, these systems are easy to scale: some designs occupy an installation space of less than one cubic meter, while others span several hundred meters.

The main difference from classical parallel robots is that the cables must always be under tension. This demands a more complex controller architecture and leads to restrictions in the usable workspace depending on the location of the suspension points. As a result, the redundancy (difference between the number of cables and degrees of freedom) of such a robot plays an important role.

The application possibilities are many: classic applications include alignment of telescopes, camera guidance in sports stadiums or construction site cranes for façade elements, and cable robots are also widely used as motion simulators and haptic controllers.

For the ARENA application center, a small-scale cable robot called Rocbot (Ros Cable roBOT) was developed to demonstrate the advantages of parallel cable robots in a confined space. Various planar and three-dimensional architectures can be realized. For control, either TwinCAT3 in combination with Matlab or the Robot Operating System (ROS) with a proprietary EtherCAT Manager can be used. The robot is currently being further developed so that it can handle pick-and-place tasks and interact with other robotic systems.