Novel Contact Sensor Concept and Prototype Based on 2-DOF Vibration Absorber System

Landmines are major problems, waste life and money. Much recent research acknowledges that the contact sensors have promising potential. In this work, a new idea of contact sensor for landmine detection is introduced. The sensor main principle is based on the concept of 2-DOF vibration absorber system (two springs and two masses), to detect the existence of an object (ex: landmine) in sand which is modeled as a 3rd spring. The sand stiffness (the 3rd spring stiffness ko) can be acquired as function of the frequency vibration absorber mode ?Abs (the frequency at which the 2nd mass has the lowest amplitude (mathematically proven: zero)). When the sand stiffness changed due to the presence of the landmine, the vibration absorber frequency ?Abs changes, and consequently the landmine can be detected. The mathematical derivation of the (?Abs-ko) relation is verified by simulations with Matlab and with finite element COMSOL Multi-physics. The system is succeeded to measure the sand stiffness up to 100kN/m. A physical prototype for the sensor is developed with sensitivity 16.85 (N/m)/Hz.