Underactuated Single-Wheeled Mobile Robot Mimicking a Human-Ridden Unicycle

Abstract

This thesis is about the comprehensive investigation of a type of unicycle robot stabilised by a lateral pendulum. A lateral pendulum is an inverted pendulum mounted on the robot?s chassis which swings sideways to provide lateral stabilisation capability. A prototype is designed and constructed from total scratch. Its development process involves mechanical design, electronics selection, control design, computer programming and system integration. A mathematical model is derived by Euler-Lagrange method for simulation study and analysis. Four formulae for lateral set-point control and turning-motion control are derived. Posture-balancing and manoeuvring tasks are investigated. A control scheme comprising of two separate robust controllers is designed for posture balancing. For manoeuvring, two control schemes based on linear quadratic method and gain-scheduling technique are proposed. All control schemes for both posture balancing and manoeuvring are verified by numerical simulations. Lastly, experiments of posture balancing are conducted with the developed prototype.