Anthony Pierson, “ASME Tilting Trike Stability Analysis”
Mentor: Andrew Dressel, Civil & Environmental Engineering

The tilting trike built by the UWM ASME Club incorporates a variable stability mechanism. The geometry of said mechanism changes the path the center of mass follows as the trike is leaned from vertical. The path of the center of mass is well understood using a kinematic model made in MATLAB. The slope of the path the center of mass takes is thought to affect the roll acceleration of the tricycle. Roll acceleration is an important metric for determining the handling characteristic of the trike. A higher roll acceleration will allow the bike to react very quickly to steering input, making it hard to control at slow forward speeds. In this study, an Inertial Measurement Unit (IMU) was used to record the roll acceleration of the tricycle as the bellcrank geometry was changed, and as the amount of friction under the rear wheel contact patches was varied. Preliminary results show a quantifiable difference in the roll acceleration as the bellcrank geometry was changed, but a very minimal change in roll acceleration as the amount of friction was changed. This preliminary data suggests that this stability mechanism does affect the roll acceleration of the tricycle. This information could be used to make tilting tricycles easier to handle because the roll acceleration could be slowed considerably. A primary application of this technology is in the cargo bike market, as the heavy and cumbersome cargo bikes could be made much easier to ride due to the decreased roll acceleration.