The Excavator That Digs to a Line It Cannot See – Mobility and Field Robotics

Built Robotics' autonomous excavator holds trench depth to within 3 centimeters of a design grade using RTK GPS for centimeter-level machine positioning, IMU-based tilt compensation, and joint-angle sensors across the boom, stick, and bucket to compute bucket-tooth position in real time. The core challenge differs from navigation tasks because the target surface doesn't physically exist yet — it's a 3D design file — and soil reaction forces continuously disturb the kinematic chain during cutting. No operator or survey stakes are required.