Smart Real-Time Obstacle Avoidance for Planetary Rovers Using Ultrasonic Sensing: Design, Hardware Integration, and Validation

Autonomous navigation is a critical requirement for planetary rovers operating in Astro-biological exploration missions, where real-time human control is limited or unavailable. This paper presents the design, integration, and validation of a low-cost ultrasonic sensing system for smart obstacle avoidance in planetary rover platforms. The system employs the HC-SR04 ultrasonic sensor interfaced with Raspberry Pi Pico microcontroller and a Turtle Board-based motor control unit. A reactive evasion algorithm, developed in Python using ROS-style message logic, enables the rover to detect obstacles at $\mathbf{3 5 ~ c m}$ range and execute immediate stop-and-turn maneuvers. The complete architecture includes sensor interfacing, motor control, power regulation, and onboard indicator feedback. Hardware validation was performed through indoor and outdoor field tests simulating planetary terrain conditions. Results demonstrated 100% successful obstacle detection and avoidance with a response delay of less than one second. The proposed system offers an energyefficient, modular solution that is suitable for integration in smallscale rovers intended for autonomous surface operations in extraterrestrial environments. This work lays the foundation for future upgrades involving multi-sensor fusion, vision support, and mapping capabilities. While the current system relies on rulebased logic, future iterations could integrate AI algorithms for adaptive obstacle prediction, terrain classification, and autonomous path planning.