Locomotion and Robotics Papers

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Running on water with big disposable shoes (PDF)

Par Lothman and Andy Ruina, submitted to PLOS ONE, April 20, 2012        
Video on Youtube     

Cornell Ranger walks 65 km (1.5 marathons),submitted to IJRR April 2012, accepted Dec 2013.

Paper, Appendix, video 1 (download) , video 2 (download) ,Website with lots of details.

A Walking Model with No Energy Cost (PDF)

Gomes, M., Ruina, A., Phys Rev E, vol 83 #3, 2011, DOI = 10.1103/PhysRevE.83.032901        
Video on Youtube.
Download News Nature spektrumdirekt.
Read more: Mario Gomes PhD thesis (2005).

Idealized walking and running gaits minimize work

Srinivasan, M. and Ruina, A. Proc. Roy. Soc. A, Vo 463, No. 2086, Oct, 2007, 2429-2446, DOI 10.1098/rspa.2007.0006.
(See also "Computer optimization of a minimal..." below.)

A Simple 1+ Dimensional Model of Rowing Mimics Observed Forces and Motions (PDF)

Cabrera, D., Ruina, A., Kleshnev, V., (in press, available online) Human Movement Science, 2006

Propulsive Efficiency of Rowing Oars (PDF)

Cabrera, D. and Ruina, A., submitted to Journal of Applied Biomechanics, 2006.

Computer Optimization of a Minimal Biped Model Discovers Walking and Running

Manoj Srinivasan and Andy Ruina, Nature Magazine. Online version: Sept 11, 2005. Print version Jan 5, 2006.

Efficient Bipedal Robots Based on Passive Dynamic Walkers

Steve Collins, Andy Ruina, Russ Tedrake, Martijn Wisse
Science Magazine, Vol. 307, Pages 1082-1085, Feb 2005.

Energetic Consequences of Walking Like an Inverted Pendulum: Step-to-Step Transitions

Arthur D. Kuo, J. Maxwell Donelan, and Andy Ruina, Exercise & Sport Sciences Reviews. 33(2):88-97, April 2005, April 2005 (see Kuo's www page).

A collisional model of the energetic cost of support work qualitatively explains leg sequencing in walking and galloping, pseudo-elastic leg behavior in running and the walk-to-run transition (PDF)

Ruina, A., Bertram, J.E.A., Srinivasan, M., Journal of Theoretical Biology, Volume 237, Issue 2, Pages 170-192, November 21, 2005.

A five-link 2D brachiating ape model with life-like zero-energy-cost motions (PDF)

Gomes, M., Ruina, A., Journal of Theoretical Biology, Volume 237, Issue 3, Pages 265-278, DOI: 10.1016/j.jtbi.2005.04.014, December 7, 2005.
Video - Brachiation (download)

Persistent Passive Hopping and Juggling is Possible Even With Plastic Collisions (PDF)

Chatterjee, A., Pratap, R, Reddy, CK, Ruina, A.
The International Journal of Robotics Research 21, No. 7, Pages 621-634, 2002

A Three-Dimensional Passive-Dynamic Walking Robot with Two Legs and Knees

Collins, S. H., Wisse, M., Ruina, A.
International Journal of Robotics Research, Vol. 20, No. 2, Pages 607-615, 2001

Multiple walking speed-frequency relations are predicted by constrained optimization (PDF)

Bertram, JEA, Ruina, A., J. of Theor. Biology, 209, Pages 445-453, 2001

Prediction of Stable Walking for a Toy That Cannot Stand Still (PDF)

Mombauer, K., Coleman, M., Garcia, M., Ruina, A., Physical Review E, Vol. 64, Issue 2, Aug 2001

Efficiency, speed, and scaling of two-dimensional passive-dynamic walking

Garcia, M., Chatterjee, A., Ruina, A.
Dynamics and Stability of Sytems, Vol. 15, No. 2, Pages 75-99, 2000

Small Slope Implies Low Speed In Passive Dynamic Walking (PDF)

Chatterjee, A, Garcia, M.
Dynamics and Stability of Sytems, Vol. 15, No. 2, Pages 139-157, 2000

A Point Mass Model of Gibbon Locomotion

Bertram, JEA, Ruina, A., Cannon, CE, Chang, Y-H, Coleman, M.
Journal of Experimental Biology, 202, Pages 2609-2617, 1999

The Simplest Walking Model: Stability, Complexity, and Scaling (PDF)

Garcia, M., Ruina, A., Chatterjee, A., Coleman, M.
ASME Journal of Biomechanical Engineering, Vol. 120, No. 2, Pages 281-288, Apr 1998
Unpublished postfacto derivations of the jump conditions therein:
Gomes version (PDF) | Sharma version (PDF)
Matlab code, by Pranav Bhounsule, for simulating the Simplest walker.
Matlab code by Mariano Garcia (includes code for various robots).

An Uncontrolled Toy That Can Walk But Cannot Stand Still (Tinkertoy Walker)

Coleman, M., Ruina, A.
Physical Review Letters, Vol. 80, Issue 16, Pages 3658-3661, Apr 1998

Motions of A Rimless Spoked Wheel: A Simple 3D System With Impacts (PDF)

Coleman, M., Chatterjee, A., Ruina, A.
Dynamics and Stability of Systems, Vol. 12, No. 3, Pages 139-160, 1997

A force analysis system for brachiation (PDF)

Chang, Y-H, Bertram, JEA, Ruina, A.
J. Exp. Biol., 200, Pages 3013-3020, 1997

Stability, Scaling, and Chaos In Passive-Dynamic Gait Models (ZIPPED PDFs)

Garcia, M., Ph.D. Thesis, Jan 1999

A Stability Study of a Three-Dimensional Passive-Dynamic Model of Human Gait (PDF)

Coleman, M. Ph.D. Thesis, Feb 1998.
This thesis details a stability study of 3D passive walking, including work on 2D and 3D rimless wheels.

Powered Passive Dynamic Walking (PDF)

Camp, J. Master of Engineering Project Report, Aug 1997 This report details a computer study of a simple powering scheme to produce stable, 2D, straight-legged walking on level ground.

1997 NSF Proposal Excerpts: Passive nonlinear-dynamic study of walking - simulation, analysis, and experiment (PDF)

Conference Papers (mostly subsumed by papers above):

Some Results In Passive-Dynamic Walking (PDF)

Euromech Conference on Biology and Technology of Walking in Munich, Germany, March 1998
Like the proposal, it is an overview of our work and results to that date in passive-dynamic walking.

Speed, Efficiency, And Stability of Small-Slope 2D Passive-Dynamic Bipedal Walking (PDF)

Summary of results in the above paper for a 1998 ICRA special session on bipedal walking.
In Proceedings of the 1998 International Conference on Robotics and Automation, Leuven, Belgium.

Stability and Chaos in Passive-Dynamic Locomotion (PDF)

Poster and Presentation from the 1997 IUTAM Conference on new applications of Nonlinear Dynamics and Chaos in Mechanics. Cornell University, July 27-August 1, 1997

Passive Dynamic Models of Human Gait (PDF)

Poster Abstract from Engineering Foundation Conference on Biomechanics and Neural Control of Human Movement, Mt. Sterling, Ohio, June 1-6, 1996