Tensegrity vehicles and manipulators
The tensegrity paradigm combines purely compressive and purely tensile members (i.e., rods and tendons) into pretensionable structures that can bear externally-applied loads and moments with exceptional mass efficiency. This paradigm is amenable to elegant and insightful modeling and analysis under certain key assumptions that are sometimes difficult to realize in practice, including (i) the connection of multiple (3 or more) rods and/or tendons at perfect and effectively massless revolute or ball joints, and (ii) the effective incorporation of the actuation and sensing components (in addition, in mobile designs, to the electronics and batteries) within the rods and tendons of the structure itself. Our lab has pushed the state of the art in realizing the tensegrity ideal in compelling hardware. We have focused on two main designs:
a mobile vehicle (DuCTT) given by two nested tetrahedrons (with rods on all edges, and the rods at opposite ends of the vehicle built as linear actuators), interconnected by vertical and saddle tendons that can change the separation and relative orientation of the tetrahedra, thus forming a vehicle that can climb and maneuver like a rock climber in HVAC ducts, and
a high-degree-of-freedom cable-driven joint that can provide controllable left-right, up-down, and twisting motions in a single cable-driven joint (overcoming some key disadvantages of the current state-of-the-art of robot arms in industry, which typically attach several single DOF joints end-to-end).