Range-Only Dynamic Output Feedback Controller for Safe and Secure Target Circumnavigation

TL;DR

This paper presents a range-only dynamic output feedback controller for a unicycle robot to safely and securely circumnavigate an unknown target, ensuring safety constraints using Lyapunov functions and only local range measurements.

Contribution

It introduces a novel control method that relies solely on range measurements and Lyapunov functions to guarantee safety and stability in target circumnavigation.

Findings

The controller ensures asymptotic stability of the circumnavigation task.

Safety and sensing constraints are satisfied throughout the motion.

Simulation and experimental results validate the theoretical approach.

Abstract

The safety and security of robotic systems are paramount when navigating around a hostile target. This paper addresses the problem of circumnavigating an unknown target by a unicycle robot while ensuring it maintains a desired safe distance and remains within the sensing region around the target throughout its motion. The proposed control design methodology is based on the construction of a joint Lyapunov function that incorporates: (i) a quadratic potential function characterizing the desired target-circumnavigation objective, and (ii) a barrier Lyapunov function-based potential term to enforce safety and sensing constraints on the robot's motion. A notable feature of the proposed control design is its reliance exclusively on local range measurements between the robot and the target, realized using a dynamic output feedback controller that treats the range as the only observable output for feedback. Using the Lyapunov stability theory, we show that the desired equilibrium of the closed-loop system is asymptotically stable, and the prescribed safety and security constraints are met under the proposed controllers. We also obtain restrictive bounds on the post-design signals and provide both simulation and experimental results to validate the theoretical contributions.