How WE RIDE Bicycles


Human control of bicycle dynamics with experimental validation and implications for bicycle design


Dale L. Peterson
Jason K. Moore
Ron Hess
Mont Hubbard

Sports Biomechanics Laboratory
Mechanical and Aerospace Engineering Department
University of California, Davis

Ability vs. Understanding

(Almost) everybody knows how to ride a bike, but (almost) no one knows how we ride a bike

Project goals

Motivation: Theoretical and Practical

How can we do this?

What is a dynamic system?

A system that changes in time. It has:

Example dynamic system with feedback control

Bicycle Human Feedback

On the bicycle, human sensory organs include:

and sense quantities like

Bicycle Human Feedback

Brain integrates all this information in real time to produce a single control signal that actuates muscles to turn handlebar. This is the process we study.

Our project is famous and award winning!

Washington Examiner

Our project is famous and award winning!

Senator Tom Coburn R-OK

Taxpayers may also question the value of many of the projects NSF actually chose to fund, such as: How to ride a bike...


Bicycle Dynamics 101

What/Why/How are we modelling?

Modelling Assumptions

Start simple!

Even with these simplifications, we still have 25 parameters to keep track of.

What do we observe in real bicycles?

Is the motion stable?

Eigenvalues vs. Speed

Unstable at 0 km/h (0 mph)


Unstable 12.6 km/h (7.9 mph)


Stable at 17.6 km/h (11.0 mph)

Unstable at 22.7 km/h (14.2 mph)


Stability of upright motions


Unconventional bicycle with stability

What is observed? Unconventional bicycle with stability

Turning Bicycles

Stability of turning motions employs same mathematical framework

Key Differences

Robotic Bicycle


Robotic Bicycle Experimental Setup


Robotic Bicycle


Theory of Human Control

Bicycle + Rider = Balance?

Feedback Model

Basic model will include:

Six Bicycles Modeled

How pilots rate aircraft “handling qualities”

Handling qualities and the helicopter pilot

Predicting a bicycle's handling qualities

V = 2.5m/s

V = 5m/s

V = 7.5m/s

Bicycle Control at Slow Speeds

Professor on a bicycle

Rider Model Results in Lane Change Maneuver

Roll angle with rider control.

Rider Model Results in Lane Change Maneuver

Steer angle with rider control.

Rider Model Results in Lane Change Maneuver with Hands Free

Rider model + bicycle in lane change with hands-free

Identifying the Rider + Bicycle System in Experiments

Instrumented bicycle
Identification results rider + bicycle roll-rate response to pulsive side forces

Experimental Identification of Rider Control

Start Experimenting: On the treadmill

Professor can now balance!

Bike Snobbery

And with that, I’d like to leave you with a quiz. As always, study the item, think, and click on your answer. If you’re right, you’ll see some sort of confirmation, and if you’re wrong you’ll see evidence of a sinister Dutch plot to create a legion of deadly supercommuters.
– Bike Snob NYC

Start Experimenting: Outside

Notice the counter-steering.

Balance with your body

Back to the Treadmill

Kinematic Motion Data

Motions and Groups


Motions and Groups


Motions and Groups

Lateral Knee, Knee Bounce

Newton's 2nd Law

F = ma

Instrumented Bicycle

Lane Change

Random Disturbances

How do we ride bicycles?

Bicycle control is adequately modeled by a linear state feedback control system which is parameterized by five gains and a neuromuscular frequency.

Wrap up

Possible new bicycle designs

This work was supported by Grant NSF CMMI-0928339 from the National Science Foundation.