Development of a Continuous Cable Tensegrity

Abstract In preparation for the development of a “two-and-a-half dimensional (2.5D)” tensegrity system formed by wrapping a network of 2D tensegrity structures around the surface of the arm, we have built a computer model and designed novel connectors. Our computer model is based on optimization techniques that solve for the position of each node while minimizing the energy of the system. It also allows for a single, continuous cable to pass through multiple nodes, something which current models do not allow. For the prototypes of our 2.5D system, we experimented on novel connectors 3D printed out of thermoplastic polyurethane (TPU), a flexible material. These connectors allow the nodes of the bars and cables to be attached to a central point and move within reasonable degrees of rotation with only small moments being applied. We have experimented with the torque the TPU nodes apply to the rods to see how close these nodes are to ideal pin joints. In this paper, we delve into our method for algorithmically solving tensegrity systems with cables passed through multiple nodes and the optimization used to solve the resultant equations. We also discuss the techniques used to validate the model through additive manufacturing and experimentation on our desired tensegrity systems.