Microrobot Design Using Fiber Reinforced Composites

Jointed exoskeletons permit rapid appendage-driven locomotion but retain the soft-bodied, shape-changing ability to explore confined environments. We challenged cockroaches with horizontal crevices smaller than a quarter of their standing body height. Cockroaches rapidly traversed crevices in 300-800 ms by compressing their body 40-60%. High-speed videography revealed crevice negotiation to be a complex, discontinuous maneuver. After traversing horizontal crevices to enter a vertically confined space, cockroaches crawled at velocities approaching 60 cm·s −1 , despite body compression and postural changes. Running velocity, stride length, and stride period only decreased at the smallest crevice height (4 mm), whereas slipping and the probability of zigzag paths increased. To explain confined-space running performance limits, we altered ceiling and ground friction. Increased ceiling friction decreased velocity by decreasing stride length and increasing slipping. Increased ground friction resulted in velocity and stride length attaining a maximum at intermediate friction levels. These data support a model of an unexplored mode of locomotion-"body-friction legged crawling" with body drag, friction-dominated leg thrust, but no media flow as in air, water, or sand. To define the limits of body compression in confined spaces, we conducted dynamic compressive cycle tests on living animals. Exoskeletal strength allowed cockroaches to withstand forces 300 times body weight when traversing the smallest crevices and up to nearly 900 times body weight without injury. Cockroach exoskeletons provided biological inspiration for the manufacture of an origami-style, soft, legged robot that can locomote rapidly in both open and confined spaces.T he emergence of terradynamics (1) has advanced the study of terrestrial locomotion by further focusing attention on the quantification of complex and diverse animal-environment interactions (2). Studies of locomotion over rough terrain (3), compliant surfaces (4), mesh-like networks (5), and sand (6-8), and through cluttered, 3D terrain (9) have resulted in the discovery of new behaviors and novel theory characterizing environments (10). The study of climbing has led to undiscovered templates (11) that define physical interactions through frictional van der Waals adhesion (12, 13) and interlocking with claws (14) and spines (5). Burrowing (15, 16), sand swimming (17), and locomotion in tunnels (18) have yielded new findings determining the interaction of bodies, appendages, and substrata.Locomotion in confined environments offers several challenges for animals (18) that include limitations due to body shape changes (19,20), restricted limb mobility (21), increased body drag, and reduced thrust development (22). Examining the motion repertoire of soft-bodied animals (23), such as annelids (19), insect larvae (24), and molluscs (25), has offered insight into a range of strategies used to move in confined spaces. Inspiration from softbodied animals has fueled the explosive growth in soft robo...

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“…5 C and D, Movie S4, and Supporting Information). The design of the robot is realized using the SCM manufacturing technique (44)(45)(46).…”

Section: Methodsmentioning

confidence: 99%

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

Jayaram

Full

2016

Proc. Natl. Acad. Sci. U.S.A.

155

112

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“…To overcome the limitations with traditional macro-scale manufacturing techniques for sub-millimeter scale articulated devices, we have developed a meso-scale rapid prototyping method called Smart Composite Microstructures (SCM) [16]. This process entails the use of laminated, laser-micromachined materials stacked to achieve a desired compliance profile.…”

Section: B Spine and Flexure Fabricationmentioning

confidence: 99%

“…Flexures are made with a custom process using thin-film polymers sandwiched between rigid composite plates [16]. Polymers are chosen for resilience and high elastic strain limit (allowing large motions with compact geometries) [18].…”

Section: Flexure Designmentioning

confidence: 99%

“…While this design is for a small DOF fin, it will be easily iterated for large DOF swimming fish, as actual fish locomotion is quite complex. The concept of a BCF propulsion mechanism is based upon a novel 'meso'-scale manufacturing paradigm called smart composite microstructures [16]. In this concept the spine is created with a sequence of rigid links separated by flexure joints.…”

Section: Introductionmentioning

confidence: 99%

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Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish

Cho

Hawkes

Quinn

et al. 2008

2008 IEEE International Conference on Robotics and Automation

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Abstract-In this paper, we present the design and fabrication of a centimeter-scale propulsion system for a robotic fish. The key to the design is selection of an appropriate actuator and a body frame that is simple and compact. SMA spring actuators are customized to provide the necessary work output for the microrobotic fish. The flexure joints, electrical wiring and attachment pads for SMA actuators are all embedded in a single layer of copper laminated polymer film, sandwiched between two layers of glass fiber. Instead of using individual actuators to rotate each joint, each actuator rotates all the joints to a certain mode shape and undulatory motion is created by a timed sequence of these mode shapes. Subcarangiform swimming mode of minnows has been emulated using five links and four actuators. The size of the four-joint propulsion system is 6mm wide, 40 mm long with the body frame thickness of 0.25mm.

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“…The Drag PARITy transmission is a millimeter scale planar linkage constructed using Smart Composite Microstructure (SCM) fabrication techniques [8]. Unidirectional carbon fiber beams form rigid links, while revolute joints are realized by polymer flexure interconnects.…”

Section: B the Drag Parity Transmissionmentioning

confidence: 99%

Passive torque regulation in an underactuated flapping wing robotic insect

Sreetharan¹,

Wood²

2011

Auton Robot

Self Cite

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Abstract-Recent developments in millimeter-scale fabrication processes have led to rapid progress towards creating airborne flapping wing robots based on Dipteran (two-winged) insects. Previous work to regulate reaction forces and torques generated by two flapping wings has largely focused on wing trajectory control. An alternative approach introduces additional degrees of freedom to the wing flapping mechanism to passively regulate these forces and torques. The resulting 'mechanically intelligent' devices can execute wing trajectory corrections to realize desired body forces and torques without the intervention of an active controller.This paper describes an insect-scale flapping wing aeromechanical structure consisting of a piezoelectric bimorph power actuator, an underactuated transmission mechanism, and passively rotating wings. The transmission is designed to passively modulate wing stroke velocity to eliminate the net roll torque imparted to the airframe.The system is modeled as having four degrees of freedom driven open-loop by a single power actuator. The theoretical model predicts lift-generating wing trajectories as well as a passive reduction in roll torque experienced by the airframe. An at-scale structure constructed using Smart Composite Microstructure (SCM) fabrication techniques provides experimental support for the theoretical model.

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Microrobot Design Using Fiber Reinforced Composites

Cited by 345 publications

References 18 publications

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

Design, fabrication and analysis of a body-caudal fin propulsion system for a microrobotic fish

Passive torque regulation in an underactuated flapping wing robotic insect

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