Micro artificial muscle fiber using NiTi spring for soft robotics

TitleMicro artificial muscle fiber using NiTi spring for soft robotics
Publication TypeConference Paper
Year of Publication2009
AuthorsKim, S., E. Hawkes, K. Cho, M. Jolda, J. Foley, and R. Wood
Conference NameIntelligent Robots and Systems, 2009. IROS 2009. IEEE/RSJ International Conference on
Date Published10/2009
Conference LocationSt Louis, MO
ISBN Number978-1-4244-3803-7
Accession Number11009882

For a new class of soft robotic platforms, development of flexible and robust actuators is quintessential. Remarkable resilience, shape memory effect, high energy density, and scalability are attributed to nickel titanium (NiTi) making it an excellent actuator candidate for meso-scale applications. This paper presents a micro-muscle fiber crafted from shape memory alloy (NiTi) coiled springs. An enhanced spring NiTi model describes the combination of martensite deformation and spring effect due to its geometry. This paper also describes a manufacturing process and characterization for micro-scale NiTi coil actuators in various annealing temperatures. The presented fiber is 400¿m in diameter and 0.5m in length exhibiting 50% contraction and 1226J/kg of energy density with 40g of force. By changing the geometry of the spring, force-displacement characteristics can be tuned. An enhanced-performance inverted-spring manufacturing method is also described and characterized. A method of discrete displacement control is presented. Taking advantage of the flexibility of micro-coil spring, we present a novel mesh-worm prototype that utilizes bio-inspired antagonistic actuation for its body deformation and locomotion.