Experimental Validation

In 2006 the 3 degree of freedom model was validated experimentally by Msc. student Jodi Kooijman at the Delft University of Technology (pdf of thesis). He built the bicycle shown below and measured the steering angle (potentiometer), lean rate and yaw rate (angular rate gyros) and the angular rotation of the rear wheel (Avocet 50 bicycle computer). During 76 runs the bicycle was laterally perterbed and allowed to coast freely at a number of different speeds mostly between 2.5 m/s and 6 m/s.   

Eigen values for the motion were then found by fiting a decaying osscillation on the measured data. These eigenvalues were compared to that of the 3 degree of freedom model and found to compare well.

The validation was presented at the ECCM 2006 conference in Lisbon, Portugal and will be printed in the Multibody System Dynamics journal shortly. 

Below is a short summery of some of the highlights during the project:

April 25, 2006: Jodi Kooijman succesfully defended his Engineering Dynamics  MSc thesis:

J. D. G. Kooijman, Experimental Validation of a Model for the Motion of an Uncontrolled Bicycle, MSc thesis, Delft University of Technology, April 2006.(pdf 4.9Mb)

May 24, 2005 : Today we did our first serious measurements with the instrumented bike in the big hall at the TUDelft sports centre. We flipped the front fork 180 degrees to get more trail and by such a larger stable forward speed range. Forward speed is now measured with the help of an old Avocet50 speedometer with a 10 magnet ring and coil pickup (thanks Jim!). The trainer wheels are to catch the bike.

Here is a  video file(2.8 Mb) of a typical (unstable) run, and here is the graph(102 KB) with the measured data (no processing, directly out of LabView). Note that we are actually measuring the stability of a steady large turn. Here is a video file(1.8 Mb) of a stable - high speed run and here is (1 Mb) a stationary (inverted pendulum) run.

March 11, 2005: First measurement data from the instrumented bicycle. This work is done by my Delft MSc student Jodi Kooijman. This is the bike:      

Note the laptop on the rear rack, the manual launcher is Jodi. The bike is instrumented with two rate gyros, one for the lean rate and one for the yaw rate. The steering angle is measured by a potentiometer. The speed is measured (temporarily) by a dynamo (originally meant for the head and tail light).  Data is collected via a USB data collecting box driven by LabVIEW and stored on the laptop. Here is an video file(2.8Mb) of the first test run, and here is the graph(23Kb) with the first measured data.