Automatic Toe-In Adjustment System for Vehicles

The project describes the development of a prototype automatic toe-in adjustment system for vehicles with four independently steerable wheels. The goal was to automate the alignment using optical sensing, servo motors, and an ESP32 microcontroller. A four-wheel steering (4WS) system was designed and built to test alignment accuracy using an infrared (IR) emitter and a photosensor pair. The mechanical frame with accessories was designed and 3D-printed in PLA. Then the wheels were replaced with lasers, which were used to reference the outcome manually. The alignment routine involved each servo sweep to detect the peak sensor and thus define each wheel’s correct alignment. Thirty tests were performed under controlled indoor conditions, and after each run, the laser reference was marked on a sheet of paper for later calculations. The system reached a mean absolute error of less than 3° and achieved full accuracy on three wheels, while the fourth wheel had 97% accuracy. The results indicate that optical sensing can be used for repeatable alignment settings and, when properly tuned, can achieve sub-degree accuracy with low-cost components. The project demonstrates that the automatic alignment with inexpensive hardware is both possible and, with tuning, a reliable option. Later development should focus on more precise motors, reduced gear drives, and improved signal stability and precision. The same approach could also be adapted for robotic calibration or other multi-axis alignment systems.