Posture regulation for unicycle-like robots with prescribed performance guarantees.

Abstract: This thesis focuses on control of nonholonomic system with particular reference to the unicycle-like robots. These are common examples of WMRs (Wheeled Mobile Robots), increasingly present in industrial and service robotics, particularly when exible motion capabilities are required. The major objective of this study is to solve the regulation problem for the unicycle model while guaranteeing prescribed performance. Dierent controllers based on either polar coordinates or time-varying laws are proposed. The main contribution is the combination of the standard control laws (both with polar coordinates and time-varying laws) that allow to achieve posture regulation for the unicycle model, with the prescribed performance control technique that imposes time-varying constraints to the system coordinates. The study also illustrates two dierent approaches to bind linear or angular coordinates, one based on a particular error transformation, and the other arising from a specific potential function. Simulations conrm the eectiveness of the proposed solutions.