Polyhedral single degree-of-freedom expanding structures: Design and prototypes

Some engineering applications require structures to expand and contract in size, while retaining their exterior shape. The applications range from mundane daily life objects to more fancy art structures. In contrast to a multi degree-of-freedom structure, a single degree-of-freedom structure can be driven by a single actuator reducing cost and simplifying the control. In this paper we study single degree-of-freedom structures that can be formed by a lattice of single degree-of-freedom polyhedral expanding units. Due to built-in symmetries, the entire structure can expand and contract as one of the units in the structure is actuated. The paper describes the design of polyhedral single degree-of-freedom systems, the structures of their dynamics/optimal control, and results from construction prototypes.