The CableRobot Simulator
The CableRobot Simulator provides a novel approach to the design of motion simulation platforms, as it uses cables and winches for actuation instead of rigid links known from hexapod simulators. This approach allows reducing the actuated mass, to scale up the workspace significantly, and provides great flexibility to switch between system configurations in which the robot can be operated. The simulator is used for studies in the fields of human perception and cognition research, flight simulation, and virtual reality applications.
The CableRobot simulator uses a parallel kinematics architecture, where the links that are rigid on other simulators are replaced by winch driven cables. While some research institutes work in the field of cable-driven parallel robots, no-one has so far developed a system for the safe transport of passengers with a focus on high performance motion simulation.
By using a cable robot design, we were able to build a motion simulator with an extraordinary power-to-weight ratio of approximately 2.6kW/kg. The simulator is operated at a maximum acceleration of 5m/s2 in a workspace of 5x6x4 m3, and maximum roll, pitch and yaw angles of ±40º, ±40º, ±5º respectively.
Using winches with a total power of 384 kW allows for cable forces of 12000N and a maximum acceleration of 14 m/s2 at a payload of 200 kg. The bandwidth of the system varies between 10 and 14 Hz depending of the cable length and cabin position inside the workspace.
The simulator cabin design is optimized with regards to stability, cabin volume, and weight. Using an icosahedron truss structure allows to minimize the weight while maximizing the cabin volume, since it provides the optimal use of components regarding the tension flow through the structure. On the other side it provides an optimal relation of nodes and edges with regards to a sphere enclosure. Using carbon fiber rods for the edges and aerospace alloy for the nodes keeps the weight below 80 kg for the whole cabin without instrumentation. For the cable topology a cross over configuration as shown in the figures was chosen to maximize the pitch and roll capability of the cabin.