Abstract
Unexploded Landmines, after wares, represent a serious problem, wastes life and money. Recent research states that contact sensors are promising. In this work, a novel contact sensor for landmine detection is presented. The sensor principle is based on the concept of 2-DOF vibration absorber system (two springs and two masses), to detect the presence of an object (landmine) in sand which is modeled as a third spring. The 3 rd spring stiffness (the sand stiffness) can be measured as a function of the vibration absorber frequency ω Abs (the frequency at which the 2nd mass gives minimum amplitude (theoretically proven: zero)) and the 1st mass gives amplitude near to peak. When the sand stiffness changes due to existence of the landmine, the vibration absorber frequency ω Abs changes, and consequently the landmine can be detected. The mathematical proof of the idea is verified by simulation on Matlab and finite element COMSOL Multi-physics. The system parameters are chosen to be appropriate with the sand-landmine stiffness measurement range. The simulation results are optimized to give best sensitivity and linearity of the sensor output. The sensor gives sensitivity of 1559 Hz/(MN/m) and linearity better than 95%. Finally, a detailed design procedure for the contact stiffness sensor for landmine detection is developed.