A Fast Laser Adjustment-Based Laser Triangulation Displacement Sensor for Dynamic Measurement of a Dispensing Robot

Zhuojiang Nan,Hui Zhao,Wei Tao,Na Lv

doi:10.3390/app10217412

Abstract

Height measurement and location by a laser sensor is a key technology to ensure accurate and stable operation of a dispensing robot. In addition, alternation of dynamic and static working modes of a robot, as well as variation of surface and height of a workpiece put forward strict requirements for both repeatability and respond speed of the location system. On the basis of the principle of laser triangulation, a displacement sensor applied to a dispensing robot was developed, and a fast laser adjustment algorithm was proposed according to the characteristics of static and dynamic actual laser imaging waveforms on different objects. First, the relationship between the centroid position of static waveform and peak intensity for different measured objects was fitted by least square method, and the intersection point of each curve was solved to confirm the ideal peak intensity, and therefore reduce the interference of different measured objects. Secondly, according to the dynamic centroid difference threshold of two adjacent imaging waveforms, the static and dynamic working modes of the sensor were distinguished, and the peak intensity was adjusted to different intervals by linear iteration. Finally, a Z direction reciprocating test, color adaptability test, and step response test were carried out on the dispensing robot platform; the experiments showed that the repeatability accuracy of the sensor was 2.7 um and the dynamic step response delay was 0.5 ms.

Highlights

With the development of modern science and technology, miniaturization of intelligent equipment has become a trend, which puts forward more stringent requirements for the processing technology of the equipment
For the above different methods, we took the z direction stability, color adaptability, and step response tests, successively, under the same conditions
A laser triangulation displacement sensor for a dispensing robot location system was developed based on the comprehensive characteristics of the actual image waveform of the laser

Summary

Introduction

With the development of modern science and technology, miniaturization of intelligent equipment has become a trend, which puts forward more stringent requirements for the processing technology of the equipment. In order to ensure the reliability of equipment processing, protective measures need to be taken. Traditional precision dispensing depends on manual work under a microscope [4], which has the disadvantages of low production efficiency, high work intensity, and inevitable human error. With the continuous development of automation and robot technology, a series of dispensing robots have been developed to improve dispensing efficiency. All the dispensing robots developed by the Nordson Corporation (USA), the Datron Corporation (Germany), and the Soonchunhyang University (Korea) [5,6] have realized automatic high-speed precision dispensing, but the price has been expensive and they have been costly to maintain. Development of a high-precision and low-cost dispensing robot has potential application prospects. The location technology of the dispensing robot is the key to ensure measurement accuracy.

Methods

Results

Discussion

Conclusion