Boston University / Center for BioDynamics / Members / John Baillieul

John Baillieul
PhD, Applied Mathematics, Harvard University, 1975
J. Baillieul
Department of Aerospace and Mechanical Engineering
Department of Manufacturing Engineering
15 Saint Mary's Street
Boston University
Boston MA 02215
(617) 353-9848
johnb@enga.bu.edu
Homepage in Department of Manufacturing Engineering.

Research Interests

My research interest lie in the fields of robotics, control of mechanical systems, and mathematical system theory. The following lists some current projects.

The Mechanics of Mobility

This research is being done with my graduate student Geoff Howell. The aim of this research is to identify the essential and basic components of the mechanics of controlled (powered) walking. Combining both theoretical and experimental analysis, we have developed what appears to be the simplest example of a controlled walking biped. We introduce an extremely simple, two-dimensional, pendulum-driven biped robot model and study its simplest locomotion strategy. The model is inspired by the slope-driven, passive-dynamic biped models of McGeer and the simplifying mass-distribution assumptions of Garcia, et al. The pendulum-driven biped is composed of two identical rigid legs connected at the hip by a frictionless, unactuated hinge. A point-mass pendulum, also attached at the hip, is held by an actuator at a constant angle in front of the biped. The actuator reacts against the stance leg, allowing the pendulum to be thought of as a torso. The equilibrium gait behavior of the pendulum-driven biped on level ground is compared, via homotopy continuation, to that of the well-studied slope-driven biped. Numerical simulation shows that the pendulum-driven biped model exhibits the same richness of gait behaviors (including period-doubling bifurcations) as slope-driven biped models, yet its gait behavior is easier to study. The homotopy continuation method is then used to find the location of previously-unreported stable period-3 gaits for the slope-driven biped.

The B.U. Smart Wing Project

This research is being done with my graduate student Matt Lee. The Boston University Smart Wing project provides an instrumented test bed to study the use of pulsed-air injection for controlling boundary layer dynamics. The aim of the research is to understand the control of fluid-flow over a wing using small amounts of air, injected in periodic bursts at carefully controlled locations along the upper surface of the wing. Wings of various geometries with Reynolds numbers in the range 150,000 - 200,000 are being used in experiments aimed at controlling flow separation and stall at high angles of attack.

The B.U. Ducted Air Flow Experiment

This reasearch is being done with my graduate student Huajun Liu. The aim of this research is to understand the characteristics and control of fluid instabilities in a low-speed axial compressor rig.

Sample publications

Further information is available at the CBD ongoing research pages. A larger list of Dr. Baillieul's publications is also available.

"Simple Controllable Walking Mechanisms which Exhibit Bifurcations," To appear in the Proceedings of the 37th IEEE Conference on Decision and Control, Tampa, Florida, December 16-18, 1998.



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