Remotely Controllable Robotic System to Detect Shallow Buried Objects with High Efficiency by Using an Holographic 4 GHz Radar

The ambit of non-destructive testing has several diagnostic methods, each with its own characteristics. The microwave high resolution imaging methods allows the detection of shallow buried objects with high plane resolution. The diagnostic method that uses the holographic subsurface radar up to 4 GHz (RASCAN 4/4000) allows obtaining images of the dielectric contrast at a high spatial resolution (about 1 cm). The scanning of large areas of several square meters with a subsurface radar requires an automatic scanning tool that must also associate the obtained dielectric contrast data with the relative position of measurement. The necessity of an automated scanning system has led to the creation of a robotic platform, equipped with a wireless remote connection, with a high degree of expandability and °exibility, also for use with other types of sensors (acoustic, ultrasonic, . . . ). The mechanical part of the robotic system consists of a motorized platform, which is entrusted with the advancement; and of a system for the scanning motion of radar head, transverse to the direction of advancement. The electronic part consists of several modules connected together by a bus 485 and connected remotely to a computer by a Bluetooth wireless connection. The developed computer software sends control instructions to the robot and plots the obtained dielectric contrast data along with the relative position of measurement to obtain a picture of the scan. The holographic radar, Rascan type 4/4000 can be programmed to scan the surface with up to 10 discrete frequencies in order to get high phase contrast for objects buried at di®erent depths. The developed robotic system successfully scans large areas of land to detect shallow buried objects, while being remotely controlled through a computer. The trajectory control was carried out on Flex board, with dsPIC R° processor onboard and programmed with Scicoslab, an integrated development environment equipped with visual pro- gramming tools. The position of robotic platform is measured with optical position sensors and used also in the trajectory control system.