Millisystems Lab


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Force Sensing Shell using a Planar Sensor (Oct. 2015)
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) and video.
Terradynamically streamlined shapes in animals and robots enhance traversability (June 2015)
We found that both cockroaches and simple robots rely on shell shape to roll the body to allow traversal through a field of compliant stalks. Chen Li, et al. Bioinspiration and Biomimetics and video
Controllable Particle Adhesion (Feb. 2013)
Controllable adhesion to glass spheres with a magnetically actuated synthetic gecko adhesive is demonstrated. Results show sphere pull-off forces can be increased 10-fold by changing the ridge orientation via the external magnetic field, and that the effective elastic modulus can be changed from 65 kPa to 1.5 MPa. movie of controllable adhesive
Gillies et al. Advanced Functional Materials, 2013
Magnetically actuated ridges
Coordinated Launching of an Ornithopter with a Hexapedal Robot (May 2015)
We develop a cooperative launching system for a 13.2 gram ornithopter micro-aerial vehicle (MAV), the H2Bird, by carrying it on 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. Rose et al. (IEEE ICRA May 2015) video
Running beyond the bio-inspired regime (May 2015)
The X2-VelociRoACH is a 54 gram experimental legged robot which was developed to test hypotheses about running with unnaturally high stride frequencies. It is capable of running at stride frequencies up to 45 Hz, and velocities up to 4.9 m/s, making it the fastest legged robot relative to size. Haldane and Fearing ( IEEE ICRA May 2015) video
Anisotropic Leg Spines for Increased Traction (May 2015)
Collapsible leg spines found on insects and spiders provide a passive mechanism for increased traction while running over complex terrain. Spiny feet for VelociRoACH reduced dimensionless Cost of Pulling by an order of magnitude while robot speed while pulling load increased by 50%. Lee and Fearing (IEEE ICRA May 2015) video
Detection of Slippery Terrain with Picket Robot (June 2014)
Experiments conducted with StarlETH (ASL, ETH Zurich) and UCB VelociRoACH using joint localization detected slippery terrain with 92% accuracy. Haldane et al. ( IEEE ICRA June 2014) video
Roll oscillation modulated turning (June 2014)
A new dynamic turning mode in legged robots is demonstrated, which uses a phase-locked gait to excite coupled height and roll oscillations. A modified robot with enhanced roll oscillations turned at 206 deg/sec at a speed of 0.4 m/s. Haldane and Fearing (IEEE ICRA June 2014) video
roll-steer roll-steer-plot
Aerodynamic Steering SailRoACH (Oct. 2013)
SailRoACH uses aerodynamic forces on its tail to turn, achieving at 1.2 meter radius turn while running at 1.6 meters per second. Scaling laws work favorably for this turning mode for fast running small robots. Kohut et al. (IEEE IROS Nov. 2013) movie
Animal-inspired Design and Aerodynamic Stabilization of a Hexapedal Millirobot
(Jan. 2013)
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. Dynamic similarity technique combined with aerodynamic damping provides stability at high speeds. D. Haldane et al. IEEE ICRA May 2013. paper Movie
Cooperative Control for Window Traversal with an Ornithopter MAV (Mar. 2013)
We demonstrate cooperative target-seeking between a 13 gram ornithopter (H2Bird), and a lightweight ground station. The ground station provides heading estimates to the ornithopter using a real-time motion tracking algorithm. Julian et al. Autonomous Agents and Multiagent Systems (AAMAS2013). link movie1 movie2

H2Bird H2Bird
A Sprawl Tuned Autonomous Robot
(Feb. 2013)
This robot has a variable leg sprawl angle in the transverse plane to adapt its stiffness, height, and leg-to-surface contact angle. Contact angle and normal contact forces are substantially reduced when the sprawl angle is low, and the velocity increases over smooth surfaces, with stable running at all velocities up to 5.2 m/s. Zarrouk et al. ICRA 2013. Movie

Dynamic Climbing of Smooth Surfaces 
(Oct.  2012)

Dynamic climbing of near-vertical surfaces introduces reaction forces which require greater normal adhesion to prevent falling. Dynamic climbing on a 30 degree slope succeeds at 12 Hz leg rate, but only  4 Hz on a 70 degree slope.  Birkmeyer, Gillies, Fearing IROS Oct 2012
dynamic smooth surface
6 legged TAYLRoACH (July 2012)
The 100-mm scale Hexapedal robot TAYLRoACH can rapidly maneuver with 90 degrees turns while running. Kohut et al. CLAWAR July 2012. Tail Maneuvers movie
OctoRoACH with Tail (May 2012)

The 100-mm scale OctoRoACH robot can turn using differential drive at 100 degrees per second, or with a dynamic tail with peak turn rates of 400 degrees per second. Pullin et al. ICRA 2012
BOLT: Bipedal Ornithopter for Locomotion Transitioning (Sept. 2011)
Bolt is a 13 gram ornithopter with legs for mixed-mode locomotion. In running modes, wings provide passive stability. With wing assisted running, BOLT can run at 2.5 m/sec while maintaining ground contact. IROS 2011 . movie
BOLT hybrid robot
DASH+Wings: Wing Assisted Running (Oct. 2011)

DASH+Wings is a small hexapedal winged robot that uses flapping wings to increase its ground locomotion capabilities. The wings increase climbing slopes and stability, but do not provide enough thrust for flight. A wing assisted running robot and implications for avian flight evolution. Bioinspiration and Bioimetics
dash + wings
Flight Control for Target Seeking by 13 gram Ornithopter (Sept. 2011)

We demonstrate autonomous flight control of 13 gram ornithopter capable of flying toward a target without any remote assistance. For this demonstration, we have developed a closed-loop attitude regulator for the ornithopter using onboard sensing and computational resources. Movie IROS 2011 .
                      seeking light
OctoRoACH:Dual Drive MilliRobot (Sept. 2011)

The OctoRoACH robot has a mass of less than 30 grams, and includes the ImageProc CPU with gyro, accelerometer, radio and camera, is capable of locomotion in rough surfaces. Robot designed by A. Pullin. Pullin et al. ICRA 2012
GSA Adhesive Material Limits (Aug. 2011)
HDPE and PP fibrillar arrays have shear adhesion stress (0.3 MPa) sufficient to deform the fibers. Hence the fiber material strength is a limit to greater adhesion strength. Surprisingly, the GSA maintained 54% of original stress in spite or marked deformation over 10,000 cycles.
Shear Adhesion Strength of Thermoplastic Gecko-Inspired Synthetic Adhesive Exceeds Material Limits, Langmuir, 2011
Wear of
                      HDPE microfibers
MEDIC Millirobot with belly climbing (May 2011)
The Medic robot has a mass of 5.5 grams, and is capable of positioning within 1 mm using static SMA drive. The robot includes camera and wireless. (Kohut et al., ICRA 2011.)
Medic Robot
DASH 16 gram Hexapedal Robot (Oct. 2009)
Using compliant fiber board as structural material, and a single main driver motor, the DASH robot is capable of 15 body lengths per second on flat surfaces. The structure is resilient and  survives ground impact at terminal velocity of 10 meters per second. IROS 2009. Video (Youtube).
DASH 16 gram
Dynamic turning by modulating leg stiffness (Sep. 2010)
The dynaRoACH robot has mass of 24 grams and is capable of running at 14 body lengths per second. By changing leg stiffness, the robot can execute a 90 degrees turn in 5 leg strides. BioRob 2010
Dynamic Turning
Altitude Regulation of iBird (Sept. 2010)

We identify free flight aerodynamic forces at a stable equilibrium point of an ornithopter and compare them with the tethered flight aerodynamic forces. We developed Closed-loop altitude regulation for the ornithopter using an external camera and onboard electronics shows that the tethered aerodynamic force measurement of a 12 gram ornithopter with zero induced velocity underestimates the total flight force by 24.8 mN.  Movie (1.1 MB .avi)
Biorob 2010 (Finalist for best paper award)
iBird hover control
Combined Lamellar Nanofibrillar Array  (Oct. 2009)
Lamellar structures act as base support planes for high-aspect ratio HDPE fiber arrays. Nanofiber arrays on lamella can adhere to a smooth grating with 5 times greater shear strength than flat nanofiber array. Langmuir, Oct 2009
RoACH 2.0 and DASH on Granular Media (Apr. 2010)
Joint work with Goldman lab at GeorgiaTech to measure cost-of-transport on granular media shows 5-30 J/kg-m at 6-10 body lengths per second. SPIE 2010
RoACH 2.0
Kids Science Challenge: Bioinspired Design  (Oct. 2009)
Bouncing passive robot construction for 3rd to 6th graders.
Kids Science Challenge
ASME Student Mechanism and Robot Design Contest (Sep. 2009)
Congratulations to Aaron Hoover for being awarded first place in the Graduate Robots Division  of the ASME Student Mechanism and Robot Design Competition, part of the
2009 ASME International Design Engineering Technical Conferences, for ``RoACH: An Autonomous 2.4 gram Crawling Hexapod Robot''! (Sep. 2, 2009)
crawler and quarter
Congratulations to Kevin Ma for being awarded second place in the Mechanisms- Undergraduate Division  of the ASME Student Mechanism and Robot Design Competition, part of the 2009 ASME International Design Engineering Technical Conferences, for ``Flexure-based Ornithopter Transmission Mechanism''! (Sep. 2, 2009) kevin flapper
Australia Broadcast Corp feature on work in Polypedal and Biomimetic Millisystem Labs (May 2009) Catalyst
big roach in hand
Directional Adhesion of Angled Microfibers (Nov. 2008)
Angled polypropylene microfibers show strong directional adhesion effects, with shear strength in direction of fibers 45 times larger than sliding against fiber directions. A 1 sq. cm. patch supported a load of 450 grams in shear. Directional adhesion of gecko inspired angled microfiber arrays, Applied Physics Letters, 2008.
angled fibers
RoACH:An Autonomous 2.4 gram hexapod robot (Sep. 2008)

A new 2.4 gram crawling robot was created which uses  laser machined glass fiber to create 57 flexure joints. The robot has on board power and electronics, and a top speed of 3 cm/sec (~ 1 body length per second).

                        and quarter
Self-Cleaning Gecko Adhesive (Sep. 2008)
First synthetic gecko adhesive which cleans itself during use, as the natural gecko does. After contamination by microspheres, the microfiber array loses all adhesion strength. After repeated contacts with clean glass, the microspheres are shed, and the fibers recover 30% of their original adhesion. The fibers have a non-adhesive default state, which encourages particle removal during contact.
Contact Self-Cleaning of Synthetic Gecko Adhesive, Langmuir 2008
self cleaning of

Fast Prototyping for Folded Millirobots (Apr. 2008)
By using posterboard, laser cutting, and lamination processes,  multi-jointed robots can be rapidly prototyped in less than 2 hours. An example 2X scale crawler model has 57 flexure joints and can be driven using shape memory alloy actuation.
Hoover ICRA 2008     Fab Process Movie   Movie of crawler
Rapidly prototyped
                      cardboard crawler
Directional Gecko Adhesive (Jan. 2008)
First easy attach, easy release, and directional synthetic gecko adhesive using hard polymer microfibers. Microfiber array using 42 million polypropylene microfibers per square centimeter. Patches can support 9 N/ in estimated contact region with preload of just 0.1N/
Sliding-induced adhesion of stiff polymer, Interface 2008
Directional gecko
High Lift with 270 Hz Wing Beat (Oct. 2007)
By increasing wing beat frequency from 170 Hz to 270 Hz, the lift force generated by a single wing increased from 500 uN to 1400 uN, more than 2X the lift required for the final 100 mg MFI to hover.
Steltz et al IROS 2007
MFI high
                      speed wing motion
High Power Density Bimorph Actuator (Oct. 2007)
Dynamometer testing  shows energy delivery of 19 uJ per cycle from a 10 mg PZT bimorph actuator, with power delivery of > 450 W/kg at 270 Hz. (By comparison, the smallest motor available at 70 mg has power density < 100 W/kg).
Steltz&Fearing, IROS 2007
piezo bimorph
ICRA 2006 Plenary Talk (May 2006)
Challenges for Effective Millirobots


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