Departmental Papers (ESE)


Kevin C. Galloway, University of Pennsylvania
Jonathan E. Clark, Florida State University
Daniel E. Koditschek, University of Pennsylvania

Document Type Working Paper

@inproceedings{ Galloway.07, Author = {Galloway, K.C. and Clark, J.E. and Koditschek, D.E.}, Title = {Design of a Multi-Directional Variable Stiffness Leg for Dynamic Runnings}, BookTitle = {ASME Int. Mech. Eng. Congress and Exposition}, Year = {2007}}


Recent developments in dynamic legged locomotion have focused on encoding a substantial component of leg intelligence into passive compliant mechanisms. One of the limitations of this approach is reduced adaptability: the final leg mechanism usually performs optimally for a small range of conditions (i.e. a certain robot weight, terrain, speed, gait, and so forth). For many situations in which a small locomotion system experiences a change in any of these conditions, it is desirable to have a variable stiffness leg to tune the natural frequency of the system for effective gait control. In this paper, we present an overview of variable stiffness leg spring designs, and introduce a new approach specifically for autonomous dynamic legged locomotion. We introduce a simple leg model that captures the spatial compliance of the tunable leg in three dimensions. Lastly, we present the design and manufacture of the multi-directional variable stiffness legs, and experimentally validate their correspondence to the proposed model.


Date Posted: 04 August 2009