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A Low-Cost Obstacle Avoidance System Prototype for Autonomous Wheelchairs Using a Servo-Mounted Ultrasonic Sensor
Author(s)
Jongchanachavawat, Wirote
Mingmuang, Noppon
Ployjirapas, Chayut
Nanan, Kwanchai
Oiumekha, Kamonwan
Cheychuen, Noppong
Noyklay, Wannatham
Laima, Polaphat
Date Issued
January 1, 2026
Type
Conference Paper
Abstract
This research presents the development of a low-cost obstacle avoidance prototype designed for mobile robotic applications, with a potential use case in autonomous wheelchairs. The system utilizes a single ultrasonic sensor mounted on a servo motor to perform multi-directional distance scanning, allowing the robot to detect and avoid obstacles in real time. An Arduino-based control algorithm interprets distance measurements at four predefined angles (30°, 60°, 120°, and 150°), enabling the robot to make navigation decisions including forward movement, turns, and retreating actions. The system was tested under various conditions: with obstacles in front, in front-left, and in all directions (front, left, and right). Results showed a 100% success rate in the simple frontal obstacle scenario, 80% in the front-left obstacle case, and 60% in the most complex environment with obstacles on three sides. The primary cause of failure was the sensor’s limitation in detecting very close objects (less than 2 cm). The findings confirm the feasibility of implementing this single-sensor approach in low-cost assistive mobility devices. The prototype demonstrates effective navigation capabilities and provides a practical foundation for future development of intelligent obstacle-avoidance systems for autonomous wheelchairs.
Citation
Smart Innovation Systems and Technologies, 468 SIST, 569-579, 2026