Development of a Low-Level Control System Based on PID and RPM Imbalance Correction for Swarm Robotics

Abstract

Swarm robots are robotic systems capable of coordinated movement in formation patterns, with roles divided into leader and follower robots. Motor speed imbalance and trajectory deviations in differential drive mobile robots can lead to position and orientation errors, negatively affecting the accuracy of target motion. This study aims to design a motor speed control system that combines a Proportional–Integral–Derivative (PID) controller with an RPM imbalance correction method, along with odometry-based evaluation of individually controlled robots. Experimental results from motor characterization using encoders indicate motor speed variations below 5%. Testing three PID parameter configurations identified an optimal setting capable of maintaining stable motor speed, while the RPM imbalance correction method successfully maintained motor speed within the range of 49–51 RPM relative to the 50 RPM target, with errors below 1%, reduced overshoot, and faster settling time. Odometry-based evaluation during triangular and square formation tests showed average distance and orientation errors below 2%, demonstrating that the proposed control system effectively improves motion stability and accuracy.