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Cornell Ranger:
Journal Paper and other Documentation

Low-bandwidth reflex-based control for lower power walking: 65 km on a single battery charge (33 pages on the pre-print version, 12 MB)
Pranav Bhounsule,  Jason Cortell, Anoop Grewal, Bram Hendriksen, J. G. DaniŽl Karssen, Chandana Paul, Andy Ruina
International Journal of Robotics Research, vol.33 no.10, 1305-1321, 2014. DOI: 10.1177/0278364914527485.

Supplementary information (appendices) for the paper above (70 pages, 19 MB)

The conference version of this paper won the CLAWAR best paper in biologically inspired Robotics prize.

Ranger Webpages2011    2010     2008     2006

More Documentation

All of the documentation below (over 100 downloadable files) was generated as student reports for credit or to document our work for lab purposes. We present it here for those who want to know more about one or another detail about the design of the mechanical hardware, the electronics or the control software on Ranger. For example, all of the onboard code is accessible here. You can use any of it for any purpose. But ...

Two things:

1) USE AT YOUR OWN RISK, nothing here is warranteed in any way, and
2) PLEASE GIVE CREDIT      for any use you make of any idea, data, document or image you use (to the Cornell Ranger project, and to the author(s)).

General Reports

The first Ranger, 2006. The first version of Ranger was largely designed and built by DaniŽl Karssen and Jason Cortell in the fall of 2006, with the help of others. This robot walked 1 km. Here are two general reports about this design.

DaniŽl Karssen report, January 2007. (1.1 MB) DaniŽl visited Cornell from Delft in fall 2006.
Jason Cortell poster (0.2 MB) presented at Dynamic walking 2007 in Mariehamn Finland. 

The first overhaul was largely overseen by Bram Hendriksen in the fall of 2007. This design walked 5 miles.

Hendriksen report, 2008. Project report for Bram's visit from Delft to Cornell.
Jason Cortell DW08 slides in pdf (0.6 MB) for a talk given at Dynamic Walking 2008 in Delft (missing some slides).
Jason Cortell IthacaHS slides in pdf (0.9 MB) for a talk given to Ithaca High School in 2008

Later overhauls leading to the 65 km walk are documented component by component (below), or in the journal paper and appendix above and Pranav's thesis below.

           Pranav Bhounsule PhD thesis 2012 (2.4 MB) and a robot walking simulator (1.1 MB) (The thesis is mostly a subset of the paper                and appendices above, but has more material on a few topics).  

Mechanical hardware

The best summary of hte overall initial design is the 2006 Karssen report above. The best summary of the final design is in the appendices for the paper above.

Hardware design drawings for Ranger 2006.

CAD drawings. zipped pdf files (16.5 MB .idw files)
Autodesk Inventor files (all the ipt files):   (215 MB)  
OR dowload individual ipt files below:
     Ankle (2.1 MB),     
     Ankle encoder housing (1.9 MB),
     Battery mount (1.2 MB),  
     Inner box (1.7 MB), Outer box (2.3 MB) 
     Outer feet differential steering (1.1 MB) (this was later replaced by inner leg twist steering in 2010),  
     Legs (0.5 MB),  
     Motor stuff (1.4 MB),  
     Pulleys (0.4 MB),  
     Top Bar (0.8 MB)  
     Screws, springs, bracket, clamp, bearing, etc (3.4 MB)

Motor bench test setup, Carlos Arango 2007 (0.5 MB pdf). This setup was subsequently used to identify a motor model reported in the main paper above.

Discovery of non-ideal aspects of motors, Jason Cortell 2010 Our high-end DC motors are variable inductance and non-constant resistance.

Hip spring design, James Doehring 2007 (1.2 MB) Used on Ranger v2008, v2010, v2011.  

Ankle, Crossbar and foot contact switch, Alexander Gates 2006. Used on all versions of Ranger.

Steering by twisting, Andrew Nassau 2009 (12 MB) This steering was used on Ranger v2010, v2011.

Hip optical encoder, Tan Yingyi 2007 (2.2 MB) Used on Ranger v2008, v2010, v2011.

Dynamic balance of legs, Rohit Hippalgaonkar 2007 (0.7 MB) A similar procedure was followed everytime the mass distribution of the robot changed (due say to adding more batteries)

Shoulder pads, antenna and battery mounts, Jon Kuriloff 2011 Used onRanger v2011.

Differential steerting, Yingyi Tan 2007 (2.9 MB). Used in v2008. Not used on v2010, v2011(see inner legs twis, above).


Electronics hardware

Main Brain board design, Ko Ihara 2006, This board was replaced after 2006.

Electronics board design procedure and standards WWW page (Cortell and McAdams) 2010-2011. Written for people using our boards or designing similar boards. Also,

Using Eagle libraries for board design I, Emily McAdams 2009 (0.5 MB)
Using Eagle libraries for board design II, Emily McAdams 2009(3.6MB)

Wiring diagram, Robot Nervous System (RNS) (Carlos Arango and Jason Cortell 2010-2011). Two ways to display this:
    excel table of connections
    ppt diagram of connections

EAGLE libraries zipped (1 MB).
Electronics boards zipped (11 MB).
Electronics modules zipped (22 MB).
LPC2XXX modules zipped (2.2 MB).
LPC3XXX modules zipped (0.6 MB).

CAN bus and H-bridge thermal testing, Seong-Hee Lee, 2008

Main brain design and bluetooth module, Jehhal Liu 2009 Used on Ranger v2010, v2011.

Module testing of RC and bluetooth modules, Emily McAdams, 2009

Lithium ion Battery charging/discharging tests, G. Michael Barrameda 2009

Electronics noise reports, Nicole Rodia, 2008: pdf1  pdf2    pdf3

D to A conversion module design, Nicle Rodia, 2009.

Onboard Software

        Complete code on  Ranger v2008 to set 5 mi record (1.6 MB)

        Modular C code for the main brain, Avtar Khalsa 2008. Used in v2008.

        Floating point calculation library report by Andrew Mui 2007 (about 0.1 MB). Used in v2006 and v2008.

ARM7 code on Ranger v2010 and v2011

   Code documentation, Nicolas Willimson 2010 (webpages)

        Inner feet motor controller + related sensors code (< 0.1MB)
        Outer feet motor controller + related sensors code (< 0.1MB)
        Hip motor controller + related sensors code (about 0.1MB)
        Inner steering motor controller + related sensor code (< 0.1MB)
        Outer steering motor controller + related sensor code (< 0.1MB) (Not used for v2010 and v2011)
        UI board code (< 0.1MB)
        CAN router code (<0.1 MB) 

        Programming the ARM7 (satellite) processors for CAN bus, Thomas Craig 2010. Used in v2010 and v2011.

Code on ARM9 (main) processors (about 0.2 MB) Used in v2010 and v2011. NOTE: Does not include control code (below) nor the estimation code (below) and C header file (for CAN communications)

Estimation code on ARM9 (main) processor (<0.1 MB) and a report by Anoop Grewal, 2012  (<1 MB) Used in v2010 and v2011

Walk controller code on ARM 9 (main brain) on Ranger v2010 to set 14.3 mi record (<0.1 MB) Used in v2010 

        Walk controller code on ARM9 (main brain) on Ranger v2011 for 40.5 mi record (0.1 MB). Used in v2011

        Controlling the UI board from ARM9 (main brain), Nan Xiao 2010 (0.1 MB). Used in v2010, v2011.

        Controller the inner leg twist steering, Andrew Nassau, 2010 (0.1 MB) Used in v2010.

        (VIDEO) Ranger starts walking from splayed configuration (40 MB) and related Report by Stephanie Schneider, 2012.


Other Software

        A labVIEW program to load parameters to the robot, download sensors variables, check errors as the robot is walking or doing something.        

                Report by Andre Harrison, 2006 (3 MB) Used in v2006, v2008  AND
                Report by John Buzzi, 2010 (1.4 MB)   LabVIEW files (4MB) Used in v2010, v2011.

        A MATLAB program for post-processing robot data collected from the labVIEW program above. 

                Report by Leticia Camargo 2009 (2.3 MB)  MATLAB files are here (60 MB). Used in v2008 AND
                Report by Satyam Saryarthi 2010 (about 1 MB) MATLAB files are here (about 1 MB). Used in v2010 and v2011.


Reports about ideas that were not implemented on Ranger

        These are all ideas that were toyed with, but not implemented.

        Ideas for developing a finite state machine for high level control are here. A similar version was used in v2010,v2011
                Presentation on Robot control, Kevin Tang 2010
                Presentation on Robot control API, Kevin Tang 2010

        Simulating the simplest walker using Altair HyperCAD Rohit Hippalgaonkar 2008 (0.4 MB)
        Altair HyperCAD code for simplest walker Rohit Hippalgaonkar 2009 (0.1 MB)

        Simulation study to find optimal way to control a dc motor. Andrew Spielberg report 2006 (0.2 MB)

        Simulations of ranger and simplest walker Josh Peterson Simulations HowTo webpages

        A controller that would enable the robot to catch itself and not fall down, Megan Berry 2007

        Ranger balance on one leg Matt Haberland 2008       

        Experimental verification of a PID control on a robot jointKo Ihara PID_control_2005 (about 0.3 MB)

        An introduction to Kalman Filter Anoop Grewal 2011

        A study on setting up a modular network control architecture on the robot, Hsiang Lee 2007  (2 MB).

        Study on using proximity sensors on foot to detect time to heel-strike, Avtar Khalsa 2007 (2 MB) and a presentation (0.8 MB) 

        Implementing I2C protocol on our micro-controller to use color sensors, Michael Digman 2011 We hoped to use the color sensors to sense the               walking track to do automating steering. 

        Color Sensor box (198 MB) (not used on Ranger)

        Hardware mounts for placing the color sensors, Jon Kurioff 2011 (2.8 MB)

        ARM9 (Main brain) Color sensor code (<0.1 MB). This code was intended to be used to use color sensors to do provide information for auto                 steering on the robot v2011. But was not used.

        Using XBeePro wireless communication - a feasibility study, Andrew Mui (0.3 MB) and a presentation (0.2 MB)

        Ranger 2006 h-bridge testing. 

        Using multiple microprocessors architecture for modular electronics design, Hsiang Lee 2008 (3MB).

        Controlling a brushless dc motor, Brian Clementi 2010 (2.2 MB)

        Brushed and brushless motors test and optimization, Violeta Crow 2011: version, version2 and data files (5.6 MB)

        A comparizon of various motors and criteria for selecting them for building robots, Dapoon Boon Long 2009: version1 and version2  

        Clutch Brake design, Matt Haberland 2006 (0.5 MB)

        Load cell design for ranger, Pulkit Kapur 2009 (3.9 MB)


Documentation for earlier powered robot attempts

Marathon Walking Robot (MWR)

This robot was finally put together in 2005. This machine did eventually walk 100s of steps. It was the prototype for some of the design concepts used in Ranger. Here are some student reports about this robot.



FE "MECH" Walking Robot

This was a student team that had great ambitions for building a robot that a person could drive. No part of this project got very far. But the reports are here for posterity.  



"RC Servo" Biped project

Student projects investigating balance possibilities for a commerically available electric biped robot.