CableRobot Simulator

world's first cable robot for passengers

Figure 1. The CableRobot Simulator. Left: a sketch of the setup. Right: lateral view of the simulator when operated.

The CableRobot Simulator is world’s first motion simulator based on a cable-driven parallel robot developed in house at the Max Planck Institute for Biological Cybernetics in collaboration with IPA Fraunhofer. This robot uses a parallel platform, typical of the common hexapod simulators, but it uses cables and winches for actuation instead of rigid links. This approach allows to reduce significantly the moved mass and also to expand massively the workspace significantly (up to \(5\times 6 \times 4 m^3\), with maximum roll, pitch and yaw angles of \(\pm40^\circ\), \(\pm40^\circ\), \(\pm5^\circ\) respectively). In comparison to the CyberMotion Simulator, the parallel structure of the CableRobot Simulator allows to achieve higher accelerations ( up to \(14 m/s^2\) at a payload of \(200 kg\)) and faster dynamics. Moreover, the use of cable grants greater flexibility, since the cables can be connected in different ways thus allowing to have different configurations in which the robot can be operated

I contributed to the modelling of the system and to the development of control and tension distribution algorithms for it. One interesting study that we performed on this system was an investigation of the vibrations that occur at the cables for different values of pre-tension. This analysis is important because these vibrations injected in the system propagate to the moving platform and can disrupt the perception of the simulated motion. Using the setup shown in Fig. 2 and power spectral density analysis we measured the natural frequencies of the cable and compared these results to the frequencies predicted by two linear models: i) the linearization of partial differential equations of motion for a distributed cable, and ii) the discretization of the cable using a finite elements model. This comparison provides remarkable insights into the limits of approximated linear models as well as important properties of vibrating cables used in CDPR.

Figure 2: Setup used in "Modeling and analysis of cable vibrations for a cable-driven parallel robot" to study cable vibrations.

Related Publications

  1. Book Chapter
    Application of a Differentiator-Based Adaptive Super-Twisting Controller for a Redundant Cable-Driven Parallel Robot
    Schenk, C.,  Masone, C., Pott, A., and Bülthoff, Heinrich H.
    In Cable-Driven Parallel Robots 2018
  2. Conference Proc. Award
    The CableRobot simulator large scale motion platform based on cable robot technology
    Miermeister, P., Lächele, M., Boss, R.,  Masone, C., Schenk, C., Tesch, J., Kerger, M., Teufel, H., Pott, A., and Bülthoff, H. H.
    In 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2016
  3. Conference Proc. Award
    Modeling and analysis of cable vibrations for a cable-driven parallel robot
    Schenk, C.,  Masone, C., Miermeister, P., and Bülthoff, H. H.
    In 2016 IEEE International Conference on Information and Automation (ICIA) 2016
  4. Conference Proc.
    Robust adaptive sliding mode control of a redundant cable driven parallel robot
    Schenk, C., Bülthoff, H. H., and Masone, C.
    In 2015 19th International Conference on System Theory, Control and Computing (ICSTCC) 2015