A no-contact laser sensor based on the Self-Mixing effect for the measurement of rotations

Abstract

The development of a no-contact sensor based on the Self-Mixing effect for the simultaneous measurement of linear and angular degrees-of-freedom (DOFs) of a moving target is presented. The sensor is made up of three laser diodes with integrated monitor photodiodes and a plane mirror target attached to the moving object. The proposed technique makes the system easier to align with respect to the traditional interferometric systems and no further optical elements are required in the laser head except for the laser chip and its integrated photodiode, thus providing an effective compact and low-cost motion control system. The linear and angular resolutions are 0.7 μm and 0.8 × 10 -3°, respectively. A series of experiments is performed to test the proposed method by direct comparison with a reference meter system, showing a linear response over a range of 1 m and ± 0.4°. Moreover, the sensor is tested under complex displacement to validate the feasibility of simultaneous measurements of more than one DOF.

Measurement of Rotation Angle about Rotating Object Based on Digital Image

“…These methods are key procedure. (2)This measurement method could measure the rotation angle about rotating object, and its precision is accurate. (3)In addition, we can use improved method to reach better precision, such as sub-hexagonal Phase Correlation, which can reach precision of sub-pixel [10].…”

“…The measurement of rotation angle about rotating object is applied in many fields, such as heavy machine, target recognition and following, satellite positioning. There are magnetic and optical measurement methods about rotation angle, these methods have their own characteristics [1][2].…”