Although the micro displacement mechanism can achieve high resolution, but in order to obtain reliable application, still need to position detection sensors. Considering the characteristics of the micro displacement mechanism, the current measurement of micro displacement device besides grating measuring system and laser interferometer measurement system, and resistance strain displacement sensor and capacitance decay displacement sensor, etc.

Resistance strain resistance decay displacement sensor is to be measured displacement ZhuanHuanLi quantity change device, mainly composed of elastomers, the resistance strain sensor and conversion circuit, etc. Using resistance strain decay of displacement sensor position closed loop control system, sensor and the micro displacement actuator can be integrated into an organic whole, without the need for additional institutions, so high sensitivity, small volume, low cost, high displacement resolution, but nonlinear error is bigger, is easily influenced by temperature.

Capacitance decay displacement sensor is the displacement is converted to electric capacity change device under test. It is essentially a capacitor with variable parameters. According to the change of capacitor parameters, can be divided into the pole pitch change type, area change type and medium type 3 kinds. In practical applications. Commonly used is a pole pitch change type and area type displacement sensor. Area change type capacitance sensor has the advantage of elm into and output a linear relationship, but compared with the right distance change type, its sensitivity is low, only suitable for measuring large displacement of the occasion. Has capacitance displacement sensor to realize the non-contact measurement, it to board level instead of electric field force between the probe and the measured a surface contact, and due to the electric field force between the board level is extremely weak, won't produce hysteresis and deformation, eliminate the contact measurement due to the negative influence of surface stress to the measurement, so this method in the field of nanoscale detection, nano machining has been widely used.