A number of telescoping structure designs were explored. Image credit: Carnegie Mellon University.Robots that can collapse themselves for transport, enter tiny spaces and reach around large obstacles: That’s one promise of recent research at Carnegie Mellon University, which has produced a method for designing telescoping structures that can bend and twist.

The research team, composed of computer science professor Keenan Crane, robotics professor Stelian Coros and computer science doctoral student Christopher Yu, will present their work at SIGGRAPH 2017. Their paper notes that telescoping structures are valuable for a variety of applications where mechanisms must be compact in size, and yet easily deployed.

While most current telescoping devices employ a “pirate’s spyglass” configuration of straight, nested cylinders, the team set out to discover other viable telescoping shapes, along with developing computational methods for designing and fabricating them.

The team discovered that spherical, ring-shaped and helical telescopes are possible. They also devised algorithms to design telescoping structures to match suggested shapes, and created a design tool to enable easy creation of complex, collapsible assemblies. Once a desired curve is selected by a designer, algorithms go to work to devise a telescoping structure that can extend or contract without bumping into itself. Computations also eliminate wasted space between nested pieces, and specially-designed connectors allow several telescopes to be combined into a larger assembly.

The researchers didn’t throw out the classic “spyglass” approach altogether. By focusing on circular cross-sections within the nested sections, they were able to get curved sections to rotate – thus adding 3D twists to what would otherwise be 2D shapes.

The design possibilities range from the practical—a rapidly deployable shelter, for instance—to the fanciful, such as a lizard that can retract its head, legs and tail.

Simulations also enabled the researchers to analyze how the telescoping devices might move if they were actuated. "We found that characters with telescoping parts are capable of surprisingly organic movements," Coros said.