Existing precision displacement-measuring devices are primarily based on linear encoders (optical or magnetic) or laser interferometers. Most encoders use grating scales and frequency counters, while most interferometers use stabilized lasers and fringe counters. In general, interferometers are more expensive and more accurate than linear encoders. However, there are large gaps in price and per...

A new heterodyne nano-displacement with error reduction is presented. The main errors affecting the displacement accuracy of the nano-displacement measurement system including intermodulation distortion error, cross-talk error, cross-polarization error and phase detection error are calculated. In the designed system, a He-Ne laser having three-longitudinal-mode is considered as the stabiliz...

The mechanical testing of micro-electro-mechanical systems (MEMS) and nano-electro-mechanical systems (NEMS) requires precise measurements of displacement and strain in the nanometer scale. Integrated testing devices, including specimens, actuators and sensors, were designed and fabricated to overcome the aligning and gripping difficulties faced by previous separated micromechanical testing app...

it is correct control and monitoring of modern embankment dams that are very vital in the geotechniqual constructions. the improvement of methods of stability control, using the effective stress and the measurement of ganglionic water pressure in embankment dams cause more the safety for this kind of dams. nowedays there is such an idea that in stead of using of being safety factor against coas...

This paper investigates the Frequency Modulation Continuous Wave (FMCW) radar sensor for multi-target displacement measurement in Structural Health Monitoring (SHM). The principle of three-dimensional (3-D) displacement measurement of civil infrastructures is analyzed. The requirements of high-accuracy displacement and multi-target identification for the measuring sensors are discussed. The fun...