Mobility for small, man-portable reconnaissance robots in the past has been limited with regard to obstacles like curbs, stairs, and vertical walls. A previous innovation overcame these obstacles by introducing rotary microspines — sharp hooks supported by elastic elements on a wheel. In this innovation, the work has been advanced with a new microspine design that eliminates the need for elastomer materials or the inserted hook.

Several variations of Microspines, which are effective on rough surfaces, including natural surfaces such as rocks.
The new design replaces the elastomer material with metal, significantly reducing manufacturing complexity, increasing performance, and providing a path to mass-fabrication techniques. The new leader-follower design uses sets of rotary microspines in a motorcycle-like configuration (one wheel in front of the other) as opposed to previous side-by-side designs. This improved the robot’s ability to climb curbs, including painted curbs, and to climb stairs, including overhanging face angles.

The rotary microspine wheel assemblies consist of a hard, inner rim connected to flexures that connect to the spine housing. These may have a back flexure also attached to the rim, stabilizing and increasing the restoring force into the surface. These back flexures are designed to bend in plane, avoiding any out-of-plane movement. The compression of this back flexure leads to bending actions that fold in on itself, producing a raised section behind the initial spine housing. This mode has been exploited as a means to increase the spine density by placing another spine in the housing at this point. This mode provides a light pinching force into the front spine, improving adhesion. These wheel sections are either separated by dividers or by spacers. The dividers double as disentanglement devices, and as a way to provide a cavity off of the surface for the spines to pass under the wheel. This space allows the microspines to disengage from the surface, while not disturbing the rolling action of the wheel. When spacers are used, similar, thicker, divider-like parts on either side of the wheel assembly provide the open cavity for all of the microspine units. The side-only design reduces weight, but has no disentanglement ability so that the spaces between the wheel units must be in creased, reducing the spine density and further decreasing weight.

This work was done by Aaron Parness of Caltech and Kalind C. Carpenter for NASA’s Jet Propulsion Laboratory.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Innovative Technology Assets Management
Mail Stop 321-123
4800 Oak Grove Drive
Pasadena, CA 91109-8099
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Refer to NPO-48999.

This Brief includes a Technical Support Package (TSP).
Document cover
Rotary Microspine Technology

(reference NPO-48999) is currently available for download from the TSP library.

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