JBike6

A Benchmark for Bicycle Motion
(linearized ODEs)

JBike6 is a computer program that determines the stability of bicycles. You can enter information about the shape and mass distribution of a bicycle, and JBike6 calculates the speeds at which that bicycle is stable all by itself, with no control.

In particular, JBike6 calculates the eigenvalues (i.e., perturbation- growth exponents: λ in solutions of the form q = ve^λt), for an idealized, uncontrolled bicycle. It then plots these linearized perturbation-growth eigenvalues over a range of forward speeds. For example, the bike shown at the right it is self-stable in the region of speeds (between 5.3 and 8 m/s) where both dark blue lines are below the x-axis.

The equations used in JBike6 are benchmarked exhaustively in a paper by A. L. Schwab, J. P. Meijaard, and J. M. Papadopoulos.

JBike6 has a graphical user interface (screen shot) and comprehensive on-line help.

If working on bicycle or motorcycle development or research, use JBike6 to:

Calculate no-hands stability of a given design over the entire velocity range. The eigenvalue plot shows exactly at what speed, if any, a configuration becomes stable, and at what speed, if any, it becomes unstable.
Check the accuracy or validity of any other bicycle or motorcycle equations you may use. JBike6 provides several sets of numbers (benchmarked to high precision) that you can use for comparison.
Apply control theory. JBike6 provides the necessary linearized equations of motion.

JBike6 was created by:

Arend L. Schwab, Assistant Professor of Applied Mechanics at Delft University of Technology. Wrote the main JBike6 engine in MATLAB.
Jim Papadopoulos, Contributing Author of Bicycling Science : Third Edition. Created the JBike concept and monitored its development. Worked closely with Scott Hand on his Master’s Thesis at Cornell University: Comparisons and Stability Analysis of Linearized Equations of Motion for a Basic Bicycle Model
Andy Ruina, Professor of Theoretical & Applied Mechanics at Cornell University. Lab advisor.
Andrew Dressel, Graduate Student of Theoretical & Applied Mechanics at Cornell University. Created JBike6 GUI, on-line help, and this JBike6 website.

Download a copy for free. Requires MATLAB, by The MathWorks, version 6.0 or higher.

Please join the JBike6 discussion or email us with questions or comments.

Last updated August 1, 2006