The development of an intelligent manual prodder for material recognition

The paper describes an active prodder for the recognition of touched materials. The proposed system has been developed with feedback from deminers expertise, keeping into consideration their remarks from past research activities for a better understanding of the reasons for failures in the adoption of the previously developed prodders. It is important to underline that this intelligent prodder is not intended to be used directly for searching mines, but as a complementary tool to recognize the material of a suspected object once it has been detected by using other tools (metal detectors, GPR, etc.). According to the statistical data many accidents on deminers occurs during prodding and excavation; as a consequence the realization of an intelligent prodder could help deminers to recognize the material just when a small part of the suspected object is cleared. The device conceived is based on piezoelectric actuating and sensing strategy and the elaboration of the obtained output signals was performed in frequency domain. Moreover, another advance was the integration of the prodder with other sensors such as a force sensor and an inclinometer. The choice to integrate a potentiometer coupled with a calibrated spring as force sensor has the function to guarantee a constant application force since the operator’s hand cannot assure it. This introduces the advantage to have a good repeatability of the piezoelectric response. The inclinometer gives useful information on the angle of attack to improve the reliability of the contact. A prototype was built and characterized in laboratory and outdoor in a simulated minefield. The activity had several phases: the study of state of art, the development of a recognition strategy and the design, fabrication and characterization of the instrumentation.