High Dynamics and Precision Optical Measurement Using a Position Sensitive Detector (PSD) in Reflection-Mode: Application to 2D Object Tracking over a Smart Surface

Abstract

When related to a single and good contrast object or a laser spot, position sensing, or sensitive, detectors (PSDs) have a series of advantages over the classical camera sensors, including a good positioning accuracy for a fast response time and very simple signal conditioning circuits. To test the performance of this kind of sensor for microrobotics, we have made a comparative analysis between a precise but slow video camera and a custom-made fast PSD system applied to the tracking of a diffuse-reflectivity object transported by a pneumatic microconveyor called Smart-Surface. Until now, the fast system dynamics prevented the full control of the smart surface by visual servoing, unless using a very expensive high frame rate camera. We have built and tested a custom and low cost PSD-based embedded circuit, optically connected with a camera to a single objective by means of a beam splitter. A stroboscopic light source enhanced the resolution. The obtained results showed a good linearity and a fast (over 500 frames per second) response time which will enable future closed-loop control by using PSD.

Design of Microfluidic Device and Measurements of MPWM for Single Cell /Particle Manipulation

“…The device design and selection of materials are important steps for fabrication of microfluidic device for biomedical, chemistry or biochemisry applications [1][2][3][5][6][7][8][9][10][11].…”

Vibration Measurement Method of a String in Transversal Motion by Using a PSD

“…There have been extensive studies on PSDs because of their numerous applications in the field of engineering. Devices used for human eye movement monitoring, machine tool alignment, vibration analysis and path tracking all utilize PSDs [ 20 , 21 , 22 , 23 , 24 , 25 ]. Unlike discrete element detectors such as charge-coupled device (CCD), a PSD can provide continuous position data and features a high position-resolution.…”

Planar Position Sensor Based on Mono Sensing Electrode and Hybrid-Frequency Excitation

“…For example, in [ 10 ], two planar gratings were diagonally mounted on a planar moving stage for detecting planar position and deflection on the nanoscale. In [ 11 , 12 ], laser speckle patterns and diffuse-reflectivity images are analyzed for measuring 2D displacement with high dynamics, and in [ 13 ], a capacitive transducer utilizing eight sensing electrodes was developed for the detection of planar displacements. However, most planar grating devices involve high costs, despite their high resolution, and the existing capacitive coupling methods generally need to solve complex capacitance signals generated by multiple sensing electrodes.…”