Vytas SunSpiral and Adrian Agogino have been awarded funding for a Phase II study for their NASA Innovative Advanced Concepts (NIAC) proposal, “Super Ball Bot - Structures for Planetary Landing and Exploration.” The proposed research aims at developing a truly multifunctional robot for planetary exploration. The multifunctional robot would be capable of being compactly packed for launch, expanded and used to absorb landing shocks much like an air bag, and then controlled to provide rolling mobility for exploration. This novel form of robot utilizes the tensegrity approach to structural design — these are structures composed of purely tensile (cables) and compressive (rods) components. Such robots could prove to be lightweight, strong, collapsible, energy efficient, and robust against high impacts and getting stuck. However, tensegrity control is oscillatory and nonlinear, thus posing formidable challenges. The proposed solution uses a synergy of control technologies from both the Intelligent Robotics Group and the Robust Software Engineering Group to overcome these obstacles. Out of more than 600 white papers originally submitted last year, only 18 were funded for Phase I, and out of these, only 6 were selected for Phase II.
As small, lightweight, and low-cost missions become increasingly important to NASA's exploration goals, teams of collapsible robots weighing only a few kilograms apiece could be conveniently packed during launch and be reliable to separate and unpack at their destination. Unfortunately, landing lightweight conventional robots is difficult with current technology. Current robot designs are delicate, requiring a complex combination of devices such as parachutes, retrorockets, and impact balloons to minimize impact forces and place a robot into a proper orientation. By contrast, tensegrity robots are built purely upon tensile and compression elements. These multi-purpose robots can be lightweight, absorb strong impacts, be redundant against single-point failures, be able to recover from different landing orientations, and are easy to collapse and uncollapse. Last year’s Phase I study showed that: 1) control algorithms for such tensegrity robots could be developed; 2) tensegrity ball structures could be built to protect a payload from significant impact (from a drop of 30 ft on Earth, equivalent to its terminal velocity on Titan); and 3) that a science mission to Titan could use tensegrity structures to reduce cost and risk, and increase scientific return.
BACKGROUND: Vytas SunSpiral leads the Dynamic Tensegrity Robotics Lab and is developing innovative new robotic hardware, actuation systems, and control theories based on these structural principles, drawing inspiration from the near-universal presence of tensegrity structures throughout biological systems.
Adrian Agogino’s work on multiagent systems and learning provides robust solutions to numerous complex design and control problems. These learning systems can be adaptive, and can generate control solutions to complex structures that are too complicated to be designed by hand.
NASA PROGRAM FUNDING: Space Technology Mission Directorate (STMD), NASA Innovative Advanced Concepts (NIAC) program
COLLABORATOR: David Atkinson, University of Idaho
Contact: Vytas SunSpiral, Adrian Agogino