2014-7 Parness: Gecko

Abstract: Fifteen years ago, advances in micros allowed new views of the micro and nano-structure on gecko’s toe pads. Several experiments occurred at a similar time that confirmed the dominant role of van der Waals forces in these adhesives. Today, we recognize gecko-like adhesives can benefit multiple Earth orbit applications by providing the capability to selectively anchor two surfaces together repeatedly and releasably. Key to this new capability, targets will not need special preparation; gecko-like adhesives can be used with cooperative and non-cooperative objects, like space debris. The van der Waals forces are fundamentally insensitive to pressure, radiation, and temperature, making them well-suited for space applications. The directional bias of these hairs provides a means of turning the adhesion ON and OFF through an applied shear load, a behavior also seen in JPL’s synthetic structures. In practice, the applied shear load is generated through a slight sliding motion. Once activated in such a manner, a pad will resist both normal and shear forces aligned roughly to the loading direction. By arranging these pads in counterbalanced pairs, triads, or quads, omni-directional grip can be achieved. This presentation will present work done to develop gecko-adhesive grippers for use in Earth orbit. These grippers have been tested on air bearing tables to simulate zero-g and the adhesive has been chamber tested to full vacuum and -60C. Recent zero-g flight experiments were conducted with grippers aboard NASA’s zero-gravity airplane, simulating the use case such grippers would encounter in orbit.

Background: Dr. Aaron Parness is the Group Leader for JPL’s Extreme Environment Robots Group and Principal Investigator of several projects on microgravity grippers and wall climbing robots. He has studied multiple methods of climbing, including insect-inspired approaches, gecko-inspired adhesives, electrostatic mechanisms, and mechanical interlocking methods like clawed climbing. He has over 35 peer-reviewed publications. His PhD dissertation at Stanford University is titled “Microstructured Adhesives for Climbing Applications”. Dr. Parness also has experience in the design and fabrication of parts at the millimeter and micrometer scales. He is expert in Shape Deposition Manufacturing techniques and developed novel 3D photolithographic approaches to molding plastic parts for multi-length scale, multi material robotic applications. At JPL, he also works in the Chief Technologist’s Office leading work on Innovation and early stage technology development programs.