Unified control of trajectory tracking and obstacle avoidance in a mobile robot using virtual forces: experimental validation

This paper presents the implementation and experimental validation of a unified control strategy for trajectory tracking and obstacle avoidance in a TurtleBot3 mobile robot. The proposed method integrates a kinematic tracking controller with a reactive obstacle avoidance scheme based on the modeling of virtual repulsive forces. This approach enables the robot to track a predefined reference trajectory while dynamically responding to static or moving obstacles, without requiring global trajectory replanning. The control law is designed within the robot's local reference frame by calculating tracking errors and modulating linear and angular velocity commands through tangential and radial components of fictitious forces derived from LiDAR measurements. The magnitude and direction of the repulsive force are defined as nonlinear functions of the obstacle’s relative distance and bearing angle, ensuring smooth and proportional evasive maneuvers while preserving tracking accuracy. A Lyapunov-based stability analysis confirms the convergence and robustness of the closed-loop system. Experimental results demonstrate the effectiveness of the proposed strategy, showing that the robot maintains accurate trajectory tracking after avoidance maneuvers, with low steady-state tracking error and bounded control inputs.