Mobile Manipulator Robot for Autonomous In‐Situ Soil Measurements in Chile Pepper Cultivation

Chile pepper farming in New Mexico faces critical constraints from water scarcity, soil salinity, and labor shortages. Precision agriculture technologies enabling data‐driven resource management offer promising solutions. This paper presents an autonomous in‐situ soil sensing system integrated with a mobile manipulator robot for automated soil data collection. The main contribution is a unified, failure‐aware autonomous soil sensing system that integrates vision‐based surface characterization, adaptive force‐controlled sensor insertion, and insertion monitoring with failure detection and recovery into a single low‐cost field‐deployable robotic platform. The system comprises a two‐stage visual alignment process using RGB‐D camera data to adapt to terrain slope and identify obstacle‐free insertion sites, a force‐based contact detection mechanism to determine sensor‐soil contact, and adaptive impedance control with Kalman filter‐based soil stiffness estimation for controlled sensor insertion. The system is implemented on a mobile platform with a six DoF manipulator and TEROS 12 soil sensor. Field evaluation across 41 sensing operations in varying soil conditions during the early chile pepper season demonstrated a 75.6% success rate, with soil measurements correctly obtained upon full sensor insertion. In 90.2% of sensing operations, the system made correct decisions, including aborts when necessary. Main limitations included the inability to detect flush surface obstacles, occasional false contact detections, and incorrect insertion completion verification. Nevertheless, the results demonstrate the feasibility of autonomous in‐situ soil sensing in chile pepper cultivation, providing a foundation for fully autonomous soil monitoring. The methods and approaches developed in this work may extend to other crops requiring in‐situ soil measurements.