Paper Title
Safe Tracking Control of an Uncertain Euler-Lagrange System with Full-State Constraints using Barrier Functions. pdf
Authors
Iman Salehi, Ghananeel Rotithor, Daniel Trombetta, and Ashwin Dani
Date
December 2020
Published in
IEEE Conference on Decision and Control (CDC)
Evolution of the joint angle for the planar robot simulation using an adaptive law with and without barrier function transformation.
Abstract: This paper presents a novel, safe tracking control design method that learns the parameters of an uncertain Euler-Lagrange (EL) system online using adaptive learning laws. A barrier function (BF) is first used to transform the full-state constrained EL-dynamics into an equivalent unconstrained dynamics. An adaptive tracking controller is then developed along with the parameter update law in the transformed state space such that the states remain bounded for all time within a prescribed bound. A stability analysis is developed that considers the EL-dynamics’ uncertainty, yielding a semi-globally uniformly ultimately bounded (SGUUB) tracking error and the parameter estimation error. The controller design is validated in simulations using a two-link planar manipulator. The results show the proposed method’s ability to track the reference trajectory while remaining inside each of the predefined state bounds.
Evolution of the velocity joint angles estimation errors for the planar robot simulation using an adaptive law with barrier function
Evolution of the position joint angles estimation errors for the planar robot simulation using an adaptive law with barrier function
Evolution of the parameter estimation error for the planar robot simulation