Electromagnetic navigation system for underground tunneling robot

Describes a navigation system for tunneling robots. The system consists of a remote position-determination technique and an automatic direction control technique. The position of a robot traveling underground is measured by our proposed magnetic sensor sheet which is spread over the ground above the construction site. The sensor sheet contains an array of magnetometer boards which are especially designed to be 1.3 mm thick and highly-sensitive. Each magnetometer in the sheet is a planar coil made using a printed-circuit-board photofabrication process and includes built-in amplifier and filter circuits. Using the measured values, the robot direction controller generates control commands through an optimal regulator and a state observer with a Kalman filter. Experiments proved that the system determines the robot position accurately and constructs tunnels precisely