3725. HERMES: Hazard Examination and Reconnaissance Messenger for Extended Surveillance
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Paper
Abstract
The University of Colorado at Boulder Aerospace Engineering Senior Projects Team HERMES (Hazard Examination and Reconnaissance Messenger for Extended Surveillance) is currently designing, building, and testing a child scout rover (CSR). This is the fourth installment in the Jet Propulsion Laboratory’s (JPL) Fire Tracker System. The Fire Tracker System is designed to operate in forest fire-prone areas for early fire identification. HERMES aims to improve the Fire Tracker System by navigating through a forest like environment to a location of interest (LOI) while determining a viable path for the Fire Tracker System’s previous installment, a large less maneuverable mother rover. To do this, the CSR must traverse over obstacles up to 2.4 inches in height, vertical discontinuities (9 inches wide by 2.4 inches deep), over leaves, dirt, grass, and up or down 20 degree inclined slopes in both open and wooded area. Additionally, the CSR must drive forward and in reverse, as well as perform 360 degree turns in place. To complete these mission objectives, the CSR uses a sensor suite for obstacle and discontinuity detection, a two-motor configuration with a drivetrain and gearbox powering 6 wheels for traversing obstacles, and a moving linear mass stage that shifts the CSR’s center of mass to enable traversing over discontinuities. While on a mission, the CSR will have the capability to detect any discontinuities using two downward angled, single beam LiDAR sensors. If a discontinuity is detected, the CSR will stop and notify the user at the ground station. The user at the ground station then commands the CSR into a semi-autonomous discontinuity traversal mode, where the CSR utilizes two ultrasonic sensors mounted on the bottom of the CSR to determine whether it is over a discontinuity or flat ground. These sensors signal the software to move the linear mass stage to shift the center of mass depending on the CSR’s position over the discontinuity. The unique challenge of crossing discontinuities, and the solution, is discussed in this paper.
