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Cornell Ranger Walks 14.3 Miles at Cornell University's Barton Hall Indoor Track

In early July 2010 it took 65,185 steps for Cornell's 4-legged bipedal robot to walk 108.5 laps on Barton Hall's 1/8-mile indoor track, setting a new world record for non-stop distance walked by an untethered legged robot - more than a half a marathon. The previous legged robot distance record was 12.8 miles, held by BigDog, Boston Dynamics' robust and capable quadraped robot. Ranger, a robot more specialized for distance than BigDog, beat that record by 1.5 miles, walking 14.3 miles on a single charge of its batteries without being touched by a human. Ranger took about 20,000 steps, over three miles, for each penny worth of electricity it used. Ranger was steered with a model-plane remote control. Commands from the remote control twist the inner pair of legs. The walking was entirely controlled by the 6 onboard microprocessors.

Because the robot walked in lanes 2 and 3, the distance per lap is a bit more than an eighth of a mile; its path was measured at  212.3 meters per lap, giving it a total walk distance of (212.3 m)(108.5) = 23,034 m = 23.0 kilometers = 14.3 miles. Ranger's long walk started Monday at 2:08 p.m. and ended at 12:48 a.m. Tuesday July 6, 2010 when its batteries went dead, for a total walk time of 10 hours, 40 minutes, 48 seconds.

The photo shows Ranger walking with Fatemeh Hasaneini, the 6 year old daughter of one of the students who worked on the Robot. The blue foam eyes are for fall protection, as are the blackfoam ears.

Ranger 2011 page
Ranger 2008 page
Ranger 2006 page

July 5-6 2010 Walk Stats:
Total steps                          65,185                
Total time                            38,448 seconds (= 10 hrs 40 min 48 seconds)
Number of laps                   108.5
Lap distance                        212.3 meters (= 0.132 miles)
Total distance                      23,034 meters (= 23.0 km = 14.3 miles)
Average time per step          0.59 seconds
Average distance per step    0.353 meters = 13.9 in
Average speed                     0.60 meter/second (= 2.15 km/h = 1.34 mph)
Power                                  24.5 watts total (about 20 watts to the motors, 4.5 to computers and sensors).
Energy                                 262 watt-hours (about 3 cents worth)
Battery                                 25.9V Lithium-ion
Robot mass                          8.46 kg (= 18.6 lb)
Cost of transport (COT)       0.49
                                            COT = Energy/(weight * distance).
                                            Energy = Energy to run the motors + Energy to power the computers and sensors.

Two days earlier Ranger walked 13 miles on one charge. So, not counting running out of juice, Ranger walked more than 27 miles without a failure.

The Team:

Principal Investigator: Andy Ruina
Lab Manager: Jason Cortell
Visiting students: DaniŽl Karssen, Bram Hendriksen, S. Javad Hasaneini, Feng Shuai, Pulkit Kapur.
Graduate students: Pranav Bhounsule, Leticia Rojas-Camargo, Rohit Hippalgaonkar, Ko Ihara, Sam Hsiang Lee, Gregg Stiesberg, Andrey Turovsky, Kevin Tang, Nan Xiao, Anoop Grewal, Petr Zaytsev.
Undergraduates: Carlos Arango, Steve Bagg, Megan Berry, John Buzzi, Amy Chen, Alexis Collins, Stephane Constantin, James Doehring, Gregory Falco, Hajime Furukawa, Alex Gates, Matt Haberland, Avtar Khalsa, Andrew LeClaire, Emily Seong-hee Lee, Reubens Lee, Alexander Mora, Andrew Mui, Nicole Rodia, Andrew Spielberg, Yingyi Tan, Chen Kiang Tang, Kevin Ullmann, Max Wasserman, Denise Wong, Joshua Petersen, Matt Coryea, Jehhal Liu, Ming-Da Lei, Dapong Boon-Long, Kirill Kalinichev, Saurav Bhatia, Thomas Craig, Phillip Johnson, Katie Hartl, Andrew Nassau, Brian Clementi, Kevin Boyd, Emily McAdams, Satyam Satyarthi, Sergio Biagioni, Nicolas Williamson
Visiting scholars: Chandana Paul, Lipeng Yuan, Amur Salim.
High school student: Ben Oswald
(please let Andy know of any accidental omissions here)

NSF Robust Intelligence; and some supplemental undergraduate support from Cornell's College of Engineering.

Thanks also to the following companies, for free samples and product discounts:
Keil Software Inc., MicroMo Electronics, CadSoft Computer, Freescale Semiconductor, Maxim Integrated Products, Inc., Infineon Technologies, Analog Devices, Inc., GMW Associates, Tyco Electronics, Molex Inc.

Media: (selected)
Network World - Cornell's Ranger robot breaks record, walks 23 km on single charge (Video with a nice narrative) (youtube link) (cached 22 MB)
MSNBC - Walking robot breaks distance record (link) (cached)
IEEE Spectrum - Cornell's Ranger Robot Breaks New Walking Record (link) (cached)
Gizmag - Ranger walking robot sets new world record at 1.34mph (link) (cached)
Wired News - Adorable Walking Robot Sets Distance Record (link) (cached)
Science Daily - Out of the Gait: Robot Ranger Sets Untethered 'Walking' Record at 14.3 Miles (link) (cached)
Post Standard - Cornell University robot walks into the record books (link) (cached)
PC World - Ranger robot breaks record, walks 23km on single charge (link) (cached)
Cornell Chronicle - Cornell's robot Ranger sets 'walking' record at 14.3 miles (link) (hd video) (cached)
Cornell Daily Sun - Student-Built Robot Walks Unofficial Distance Record (link) (newpaper-cutting)
Ithaca Times - Cornell robot logs 14.3 miles for mileage record (link) (newpaper-cutting)

Videos: (Best viewed in Quicktime)
Ranger side view during walk: High (80.2 MB), Medium (1.9 MB), Low (0.37 MB)
Ranger close up: High (108.1 MB), Medium (4.2 MB), Low (0.8 MB )
Ranger battery drained: High (101.9 MB), Medium (3.9 MB), Low (0.74 MB )
Ranger 1 lap, close up: High (40.2MB), Medium (22 MB), Low ( 4.3 MB)
Ranger 1/2 lap, wide angle: High (13.3 MB), Medium (13.1 MB), Low (2.4 MB) 

For high-definition professional quality video of Ranger, and professional photographs, contact Claudia Wheatley <>.

Pictures: (click to view full resolution pics)

Left to Right: Fatemeh Hasaneini, Jason Cortell, Cornell Ranger, Lipeng Yuan, Pranav Bhounsule, Matthew Proudlove

Left to Right:  Jason Cortell, Lipeng Yuan,  Matthew Proudlove, Fatemeh Hasaneini

Left to Right: Cornell Ranger, Jason Cortell (on cart), Lipeng Yuan

Left to Right: Jason Cortell, Cornell Ranger, Petr Zaytsev, Pranav Bhounsule

Left to Right: Cornell Ranger, Jason Cortell (on cart), Petr Zaytsev

Left to Right: Jason Cortell, Cornell Ranger, Petr Zaytsev

Left to Right: Pranav Bhounsule, Jason Cortell, Cornell Ranger, Lipeng Yuan

Jason Cortell, Cornell Ranger

Left to Right: Javad Hasaneini, Fatemeh Hasaneini, Jason Cortell, Lipeng Yuan, Cornell Ranger

Left to Right: (Front) Fatemeh Hasaneini, Cornell Ranger. (Back) Petr Zaystev, Javad Hasaneini, Jason Cortell, Pranav Bhounsule, Lipeng Yuan, Matthew Proudlove.

Cornell Ranger

Cornell Ranger

Left to Right: Matthew Proudlove, Fatemeh  Hasaneini, Cornell Ranger

Cornell Ranger, Fatemeh Hasaneini

Jason Cortell, Cornell Ranger

Jason Cortell, Cornell Ranger

Left to Right: Cornell Ranger, Jason Cortell.

Left to Right: Jason Cortell, Cornell Ranger

Cornell Ranger data monitoring software

Pranav Bhounsule, Cornell Ranger

Left to Right: Fatemeh Hasaneini, Cornell Ranger