IMPLEMENTATION AND EXPERIMENTAL VALIDATION OF A REAL-TIME AUTOPILOT SOFTWARE SYSTEM FOR DATA COLLECTION AND ANALYSIS ON A SCALE SHIP MODEL IN THE MANEUVERING AND SEAKEEPING BASIN OF THE BULGARIAN SHIP HYDRODYNAMICS CENTRE (BSHC) AT THE BULGARIAN ACADEMY OF SCIENCES (BAS)

Abstract

The development of autonomous control systems for marine vessels is a key factor in increasing safety, efficiency, and autonomy in maritime transport. This paper presents the implementation and experimental validation of a real-time autopilot software system specifically designed for scale models of ships in the Maneuvering and Seakeeping Basin of the Bulgarian Ship Hydrodynamics Centre (BSHC) at the Bulgarian Academy of Sciences (BAS). The system integrates the classical Line-of-Sight (LOS) guidance law with a fixed lookahead distance and a PID course controller with derivative feedback on yaw rate and anti-windup protection.

The hardware platform includes a Qualisys optical motion tracking system (6 DOF), an onboard Innalab AHRS, and precise Faulhaber and Advanced Motion Controls servo actuators. The software architecture ensures a deterministic 100 Hz control loop, modularity, and comprehensive data logging. Experiments (course keeping, path following, zigzag maneuvers, and turning circles) demonstrate good agreement between simulation predictions (first-order Nomoto model) and real-world results – RMS cross-track error below 0.12 m and mean heading error below 3.5°.

The results confirm the practical applicability of the proposed system for data collection and algorithm validation in a controlled basin environment. Directions for future improvements are proposed, including closed-loop speed control and integration with ROS 2.