Some of the machines below also have videos.
Persistent Passive Hopping and Juggling is Possible Even With Plastic
Chatterjee, A., Pratap, R, Reddy, CK, Ruina, A.
The International Journal of Robotics Research 21, no. 7 (2002): 621-634 pdf(300k)
Multiple walking speed-frequency relations are predicted by constrained
Bertram, JEA, Ruina, A, J. of Theor. Biology, 209,445-453, 2001. pdf(160k)
An Uncontrolled Toy That Can Walk But Cannot Stand Still.
Coleman, M, Ruina, A, Physical Review Letters April 1998, Vol 80, Issue 16 pp. 3658 - 3661.
pdf (140k) ps (340) ps.Z (140k) Or download the pdf reprint from the PRL website.
This paper describes how to build a 3D Tinkertoy walking model. To build your own, (1) Go to http://www.amazon.com/ (2) Search for Tinkertoy King Size (3) Click on TInkertoy King Size (122 Pieces). The green hinges are now purple.
Prediction of Stable Walking for a Toy That Cannot Stand Still
Mombauer, K., Coleman, M., Garcia, M., Ruina, A., 2001. Physical Review E, Volume 64, Issue 2, August. pdf (120K)
Not-for-publication error analysis of this stability calculation. (pdf 220k)
A force analysis system for brachiation.
Chang, Y-H, Bertram, JEA, Ruina, R, J. Exp. Biol. 200: 3013-3020, 1997
pdf (310k) ps (1.2meg) ps.Z (460k)
1997 NSF Proposal Excerpts: Passive nonlinear-dynamic study of walking --- simulation, analysis, and experiment
pdf (290k) ps (620k) .ps.Z (290k)
Conference Papers (mostly subsumed by papers above)
Some Results In Passive-Dynamic Walking. 1998
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. pdf (210k) ps.Z (1.2meg)
Speed, Efficiency, And Stability of Small-Slope 2D Passive-Dynamic Bipedal Walking.
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. pdf (290k) ps (960k) ps.Z (340k)
Passive Dynamic Models of Human Gait.
Poster Abstract from Engineering Foundation Conference on Biomechanics and Neural Control of Human Movement, Mt. Sterling, Ohio, June 1-6, 1996. pdf (50k) .ps (70k) .ps.Z (30k)
Stability and Chaos in Passive-Dynamic Locomotion.
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. .pdf (280k) .ps (790k) .ps.Z (280k)
John Camp's Master of Engineering Project Report. 1997
detailing a computer study of a simple powering scheme to produce stable, 2D, straight- legged walking on level ground. August .pdf (110k) ps (220k) ps.Z (100k)
Mariano Garcia's PhD Thesis, 1998
Prologue PS Prologue (4meg) PDF Prologue (1.5meg)
Introduction PS Chapter 1 (500k) PDF Chapter 1 (140k)
Methods, Details PS Chapter 2 (10meg) PDF Chapter 2 (500k)
Simplest Walker PS Chapter 3 (1.8meg) PDF Chapter 3 (350k)
More Complicated 2-D Walkers PS Chapter 4 (3.3meg) PDF Chapter 4 (600k)
3 -D Walkers PS Chapter 5 (1.7meg) PDF Chapter 5 (300k)
References PS References (180l) PDF References (75k)
Mike Coleman's PhD Thesis, 1997
detailing a stability study of 3D passive walking, including work on 2D and 3D rimless wheels.
.pdf (4.4meg) ps (10meg) ps.Z (3.5meg)