VelociRoACH, hexapedal millirobot, Biomimetic Millisystems Lab, Berkeley, California, USA

Animal-inspired Design and Aerodynamic Stabilization of a Hexapedal Millirobot

The VelociRoACH is a 10 cm long, 30 gram hexapedal millirobot capable of running at 2.7 m/s, making it the fastest legged robot built to date, relative to scale. We present the design by dynamic similarity technique and the locomotion adaptations which have allowed for this highly dy- namic performance. In addition, we demonstrate that rotational dynamics become critical for stability as the scale of a robotic system is reduced. We present a new method of experimental dynamic tuning for legged millirobots, aimed at finding stable limit cycles with minimal rotational energy. By implementing an aerodynamic rotational damper, we further reduced the rotational energy in the system, and demonstrated that stable limit cycles with lower rotational energy are more robust to disturbances. This method increased the stability of the system without detracting from forward speed.

By: Duncan W. Haldane, Kevin C. Peterson, Fernando L. Garcia Bermudez, and Ronald S. Fearing

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We discovered new turning gaits for under actuated running robots. Using natural body oscillations to modulate foot forces we were able to get highly maneuverable turning.

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The X2-VelociRoACH running at record setting speeds.

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Media for the ICRA 2015 publication: "Coordinated Launching of an Ornithopter with a Hexapedal Robot"

We develop a cooperative launching system for a 13.2 gram ornithopter micro-aerial vehicle (MAV), the H2Bird, by carrying it on the back of a 32 gram hexapedal millirobot, the VelociRoACH. We determine the necessary initial velocity and pitch angle for take off using force data collected in a wind tunnel and use the VelociRoACH to reach these initial conditions for successful launch.

By: Cameron J. Rose, Parsa Mahmoudieh, and Ronald S. Fearing

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We created a low-cost, light-weight force-torque sensor using photointerrupters with force sensivity of 17 mN. This sensor can be used for body contact location as well as environment drag forces. J. Goldberg and R. Fearing, (IEEE IROS 2015).

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Media for the ICRA 2016 publication: "Step Climbing Cooperation Primitives for Legged Robots with a Reversible Connection"

This video demonstrates step climbing cooperation primitives that enable a team of two VelociRoACH robots to climb a taller step than they could individually. The addition of a winch module that exerts tensile forces on a tethered magnetic connector allows the robots to form connections, provide tether pulling assistance, and remove connections. Successful trials for (I) single robot transition, (II) form connection, (III) connected climbing, (IV) release connection, and (V) tether-assisted climbing primitives are shown. When these independent primitives are performed sequentially, the robot team can climb a high-traction sandpaper step 6.5 cm in height, which is tall relative to their 10 cm body length.

By: Carlos S. Casarez and Ronald S. Fearing

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VelociRoACH with anisotropic claws for improved traction and reduced cost of pulling.

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Coupled VelociRoACHes for high-rate turning. T. Seo, C. Casarez, and R. Fearing, ICRA 2017.

"High-rate controlled turning with a pair of miniature legged robots"

by TaeWon Seo, Member, IEEE, Carlos S. Casarez, Ronald S. Fearing
May 29 - June 3, 2017

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