A Linear Parameter-Varying Control Method for Inline Wheel Systems

Abstract

The design of the bicycle and other single-track systems are continually evolving and have become a key tool for people and goods transportation worldwide [1],[2]. The form factor, carrying capacity, maneuverability, and cost of single-track vehicles makes them advantageous in a variety of circumstances and justifies their use case in the 21st Century [2] [3],[4]. As autonomous double track vehicles arrive on public roads, it is natural that single-track autonomous systems will be developed as well; however, the unstable and non-minimum phase dynamics of single-track vehicles make their control have an additional layer of complexity compared to double track vehicles. Although many researchers have provided commentary on the stability and tracking of a riderless bicycle, relatively few bodies of work have validated their analysis through experimental testing. This work successfully demonstrates that, through gain scheduling, a PID-type controller can balance a riderless single-track vehicle by using a linear actuator to implement front-fork steering control. This control system is novel in the way in which the front fork is actuated. The manual PID tuning process outlined in this body of work is also unique, as well as the specifics of the control law (although PID controllers have been used by other authors). The works of other authors on this topic is briefly summarized and a second-order dynamics system model is derived. Then controller analysis is simulated and then validated experimentally. Suggestions are also made on next steps that can be taken to build upon the work outlined in this thesis.