CN115031657A

CN115031657A - 3D laser displacement sensor

Info

Publication number: CN115031657A
Application number: CN202210640042.6A
Authority: CN
Inventors: 杨鹏; 骆聪; 刘路青; 袁春辉; 唐磊; 杨君; 曹葵康; 蔡雄飞
Original assignee: Tztek Technology Co Ltd
Current assignee: Tztek Technology Co Ltd
Priority date: 2021-11-10
Filing date: 2022-06-08
Publication date: 2022-09-09

Abstract

The invention provides a 3D laser displacement sensor, which belongs to the technical field of measurement and sensing and comprises a laser, an inclined lens, a camera, a driving and controlling circuit, a shell and a telecommunication interface, wherein the laser, the lens and the camera are vertically arranged and are in telecommunication connection with the driving and controlling circuit so as to realize the on-off control of information acquisition; the laser comprises a low thermal change coefficient base line, a temperature sensor is added, and nonlinear temperature compensation is carried out through a nonlinear compensation model; the camera and the lens adopt a multiple exposure mode and a multiple rate exposure mode, can well meet the adaptability requirements on the material quality and the environmental temperature of the workpiece in the actual working scene, and are convenient to popularize and apply in the field of industrial quantity detection.

Description

3D laser displacement sensor

Technical Field

The invention relates to the field of sensors, in particular to a 3D laser displacement sensor.

Background

The displacement sensors are also called linear sensors, and are classified into inductive displacement sensors, capacitive displacement sensors, photoelectric displacement sensors, ultrasonic displacement sensors, and hall displacement sensors, and classified into linear displacement sensors and angular displacement sensors according to the movement mode. It is widely used industrially. And the 3D displacement sensor realizes the scanning and measurement of the surface profile of the object based on the laser triangulation distance measurement principle. Each exposure can be used for simultaneously detecting depth information of hundreds of points on one line, 3D point cloud of the surface appearance of an object can be obtained through mobile scanning, and the 3D point cloud is analyzed and processed to realize accurate measurement of 3D geometrical characteristics of the object, such as step height, flatness, curved surface profile degree and the like. However, the existing sensor still has the problems of imaging dynamic range and temperature drift, and cannot meet the adaptability requirements on the material of the workpiece and the ambient temperature in the actual working scene. Therefore, a high-precision, high-speed and high-performance 3D laser displacement sensor oriented to industrial multi-scenes is needed.

Disclosure of Invention

In order to overcome the disadvantages of the prior art, the present invention is directed to a 3D laser displacement sensor, which can solve the above problems.

A3D laser displacement sensor comprises a laser, a lens, a camera, a driving and controlling circuit, a shell and a telecommunication interface, wherein the laser, the lens, the camera and the driving and controlling circuit are vertically arranged, the laser, the lens, the camera and the driving and controlling circuit are arranged in the shell, and the telecommunication interface is installed on the shell; wherein, the laser comprises a low thermal change coefficient base line, a temperature sensor is added, and nonlinear temperature compensation is carried out through a nonlinear compensation model.

Furthermore, the laser comprises a laser diode and a laser control driving unit, and the laser control driving unit is connected with the drive control circuit and receives a power supply and a drive control instruction.

Furthermore, a driving circuit of the camera is connected with the area control circuit and receives a power supply, imaging information and a driving control instruction; the camera and the lens adopt a multi-exposure mode and a camera multi-thank rate exposure mode, and a dynamic range of 160dB is realized.

Compared with the prior art, the invention has the beneficial effects that: the 3D laser displacement sensor solves the problem of temperature drift through a temperature compensation scheme, and the multi-exposure mode improves the speed measurement, can well meet the adaptability requirements on the material quality of a workpiece and the environmental temperature in an actual working scene, and is convenient to popularize and apply in the field of industrial quantity detection.

Drawings

FIG. 1 is a schematic structural diagram of a 3D laser displacement sensor according to the present invention;

fig. 2 is a real object diagram of the 3D laser displacement sensor of the present invention.

In the figure:

1. a laser; 11. a laser diode; 11. a laser control drive unit;

2. a lens arranged obliquely;

3. a camera;

4. a drive control circuit;

5. a housing;

6. a telecommunication interface.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

A3D laser displacement sensor, referring to fig. 1 and fig. 2, the 3D laser displacement sensor comprises a vertically arranged laser 1, an obliquely arranged lens 2, a camera 3, a driving and controlling circuit 4, a shell 5 and a telecommunication interface 6.

Arrangement relation: the laser 1, the lens 2, the camera 3 and the driving and controlling circuit 4 are arranged in the shell 5, the telecommunication interface 6 is installed on the shell 5, wherein the laser 1, the lens 2 and the camera 3 are in telecommunication connection with the driving and controlling circuit 4.

The laser 1 comprises a laser diode 11 and a laser control driving unit 12, and the laser control driving unit 12 is connected with the driving and controlling circuit 4 and receives power supply and driving and controlling instructions.

The driving circuit of the camera 3 is connected with the area control circuit 4 and receives a power supply, imaging information and a driving control instruction; so as to realize the on-off control of information acquisition.

Wherein, the laser 1 and the lens 2 are arranged to form an included angle according to the Sahm's law. In a specific example, the camera 3 may be a CMOS or CCD camera, where CMOS is preferred.

A laser emission window (not shown) is formed on the housing 5 below the laser 1 and the lens 2.

Low-temperature drift structure design and temperature compensation technology: the laser 1 includes a low coefficient of thermal variation baseline and a temperature sensor (not shown) is added for non-linear temperature compensation by a non-linear compensation model. The temperature compensation scheme combining software and hardware is characterized in that a 3D laser displacement sensor base line is made of a low-thermal expansion material, the structural design of the whole machine is carried out by taking the base line as a reference, a nonlinear compensation model is established, and the measured value of the sensor is compensated according to the base line temperature. The baseline of low thermal expansion causes the line laser to generate only small measured value deviation in a larger temperature range, and the nonlinear compensation model can reflect the temperature drift of the system more accurately. The temperature compensation model and algorithm can be implemented by using the existing temperature compensation technology. The scheme guarantees the measurement accuracy of the sensor on the aspect of hardware, and considers nonlinear factors introduced by distortion of optical devices and the like, so that higher measurement accuracy can be obtained in a larger temperature range.

High dynamic imaging technology: the camera 3 and the lens 2 adopt a multi-exposure mode and a camera multi-pass rate exposure mode, the ultrahigh dynamic range of 160dB is achieved, the outline of each position is extracted from the optimal image, and the outline extraction precision is guaranteed.

In a specific example, the wavelength of the laser 1 is 300nm to 500nm, the working distance is 25mm to 100mm, the line width is 15um to 50um, and the line length is greater than 5 mm.

Two expected product parameters obtained according to the above protocol are shown in the following table:

item number	TZLS-1000	TZLS-2000
			Number of X pixels	1280	2048
Number of Z pixels	1024	1400
			Pixel size (um)	6.6×6.6	6.6×6.6
Z-direction measuring range (mm)	40	50
			Vertical resolution (um)	1.1\|1.3\|1.5	1.25
Reference working Range (mm)	90	＞84

The relevant parameters of the laser diode 11 and the lens 2 are as follows:

wavelength: 300 nm-500 nm wavelength;

working distance: 25 mm-100 mm;

line width: 15um to 50 um;

depth of focus:

>±1mm；

wire length: >5 mm;

depth of field: 1-30mm (depth of field depends on Z-direction resolution and CMOS pixel count);

fan angle: TZLS-1000 is 15-45 degrees; TZLS-4000 was 21 °.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. The utility model provides a 3D laser displacement sensor which characterized in that: the 3D laser displacement sensor comprises a laser (1), a lens (2), a camera (3), a driving and controlling circuit (4), a shell (5) and a telecommunication interface (6), wherein the laser (1), the lens (2), the camera (3) and the driving and controlling circuit (4) are vertically arranged, the laser (1), the lens (2), the camera (3) and the driving and controlling circuit (4) are arranged in the shell (5), and the telecommunication interface (6) is installed on the shell (5), wherein the laser (1), the lens (2) and the camera (3) are in telecommunication connection with the driving and controlling circuit (4) so as to realize the on-off control of information acquisition; the laser (1) comprises a low thermal coefficient of variation baseline, a temperature sensor is added, and nonlinear temperature compensation is carried out through a nonlinear compensation model.

2. The 3D laser displacement sensor according to claim 1, wherein: the laser (1) comprises a laser diode (11) and a laser control driving unit (12), wherein the laser control driving unit (12) is connected with the driving and controlling circuit (4) and receives power supply and driving and controlling instructions.

3. The 3D laser displacement sensor according to claim 1, wherein: the driving circuit of the camera (3) is connected with the area control circuit (4) and receives a power supply, imaging information and a driving and controlling instruction; the camera (3) and the lens (2) adopt a multi-exposure mode and a camera multi-pass rate exposure mode to realize a dynamic range of 160 dB.

4. The 3D laser displacement sensor according to claim 1, wherein: the wavelength of the laser (1) is 300 nm-500 nm, the working distance is 25 mm-100 mm, the line width is 15 um-50 um, and the line length is more than 5 mm.