Ground Robot-based Sensing Device with Launcher-Retrieval System for Volcano Crater Lake pH and Temperature Monitoring

Changes in volcanic activity are frequently correlated with geochemical changes in crater lake waters. Volcanologists employ periodic surveys of the volcano crater lake which include pH and temperature monitoring. Due to the exposure of volcanologists to volcanic hazards, a robotic remote monitoring system was implemented in this study. A ground robot with a tethered sensing device, launcher, and retrieval system is investigated for pH and temperature real-time data sensing considering the challenging conditions of Taal Crater Lake in the Philippines. The sensing device has a tethering system attached to two mechanisms: the launcher and the retrieval systems. From the test experiments, it was found that the system can project the sensing device for a horizontal distance of 3 meters and retrieve it smoothly. The pH and temperature sensors in the device were calibrated and demonstrated acceptable levels of error and reliability. An actual test on a lake environment was implemented. The remote-controlled ground robot can navigate the sensing device to the required default position near the lake shore and effectively launch the sensing device into the water. Moreover, the tethered sensing device successfully performed real-time pH and temperature data sensing of the water and was securely retrieved from the water back to the ground robot. After the real-time data were assessed and validated, the average errors for the temperature and pH data were only 0.44% and 1.8%, respectively.