What Is a Triangulation Sensor?

The ultrasonic sensor is a sensor developed using the characteristics of ultrasonic waves. Ultrasound is a mechanical wave with a vibration frequency higher than that of sound waves. It is generated by the transducer chip under the excitation of voltage. It has a high frequency, a short wavelength, and a small diffraction phenomenon. Dissemination and other characteristics.

Ranging sensor

Advantages of laser ranging sensors: Core technical indicators of laser ranging sensors LDM301

1.Laser ranging sensor

2. The measurement distance range is 0.5-300 meters, 3000 meters (reflection plate is required)

3.The whole process accuracy error is 20 mm

4. The continuous service life of the laser exceeds 50,000 hours (5 years)

5, with standard RS232, RS422 communication serial port and Ethernet interface

6, with both digital signals and 4-20MA analog output. Maximum distance of analog signal can be set by yourself

7.The laser ranging sensor can be compatible with the Ethernet standard ASC2 code.

8.Simple and practical communication software guarantees accurate and convenient field work

industry sector

1.Apply to taxi meter detection system

In order to save energy and reduce emissions, and to meet the measurement needs of the development of the electric vehicle industry, the mobile electric taxi meter detection system was officially launched. The detection device is roughly divided into two parts, one is a host similar in size to a password box, placed on the back seat of the car, and the other is a distance measuring sensor, which is adsorbed on the body. According to reports, the device uses the driving distance measurement method. The driver drives a certain distance while driving, and the detection device and the meter will sample simultaneously. The entire testing process is expected to be completed in seven or eight minutes. ^[2]

First, the development of transmission time laser distance sensor Laser has a wide range of applications in the detection field, is very rich in technical content, and has a very significant impact on social production and life. Laser ranging is one of the earliest applications of lasers. This is because the laser has many advantages such as strong directivity, high brightness, and good monochromaticity. Before 1965, the Soviet Union used laser to measure the distance between the earth and the moon (380 & acute; 103km) with an error of only 250m. In 1969, Americans placed mirrors on the lunar surface after landing on the moon, and also used lasers to measure the distance between the earth and the moon, with an error of only 15 cm. The basic principle of measuring distance using laser transmission time is to determine the target distance by measuring the time required for the laser to travel to and from the target. That is: although the transmission time laser ranging is simple in principle and simple in structure, it was mainly used in military and scientific research before, but it is rare in industrial automation. Because laser ranging sensors are too expensive, they usually cost thousands of dollars. Virtually all industrial users are looking for a sensor that can achieve precise distance detection over longer distances. Because in many cases the installation of sensors at short distances is limited by physical location and production environment, today's transmission time laser ranging sensors will solve the problems for engineers in such occasions.

Second, the working principle When the laser sensor is working. Transit time Laser sensors must measure transit time extremely accurately because the speed of light is too fast. For example, the speed of light is about 3 & acute; 108m / s. To achieve a resolution of 1mm, the electronic circuit of the transmission time ranging sensor must be able to distinguish the following extremely short time: 0.001m & cedil; (3 & acute; 108m / s) = 3ps To distinguish the time of 3ps, this is an excessively high requirement on electronic technology, and the implementation cost is too high. But today's cheap transit time laser sensors cleverly avoid this obstacle, using a simple statistical principle, that is, the average rule achieves a resolution of 1mm, and can guarantee the response speed.

3. Solving problems that cannot be solved by other technologies. The transmission time laser distance sensor can be used in situations where other technologies cannot be applied. For example, when the target is close, the ordinary photoelectric sensor that calculates the reflected light from the target can also complete a large number of precise position detection tasks. However, when the target distance is far away or the target color changes, ordinary photoelectric sensors are difficult to cope with. Although advanced background noise suppression sensors and triangulation sensors work well when the color of the target changes, the predictability of performance deteriorates when the target angle is not fixed or the target is too bright. In addition, the general range of the triangulation sensor is limited to 0.5m. Although the ultrasonic sensor is also often used to detect objects at a long distance, and because it is not an optical device, it is not affected by color changes. However, ultrasonic sensors measure distance based on the speed of sound, so they have some inherent disadvantages and cannot be used in the following situations.

Where the target to be measured is not perpendicular to the transducer of the sensor. Because the target of ultrasonic detection must be within an angle of no greater than 10 ° from the vertical azimuth of the sensor.

Where a small beam diameter is required. Because the general ultrasonic beam is 0.76cm in diameter when it is 2m away from the sensor.

Where a visible light spot is required for position calibration.

Windy occasions.

Vacuum occasions.

Where the temperature gradient is large. Because this situation will cause changes in the speed of sound.

Where quick response is required.

The situation where the air density changes greatly. Changes in density will cause changes in the speed of sound.

The laser distance sensor can solve all the above situations.

Fourth, a wide range of uses in the field of automation Nowadays, in addition to ultrasonic sensors and ordinary photoelectric sensors, a new method capable of solving long-distance measurement and inspection is added to the method of automatic detection and control-transmission time laser distance sensor. It provides application flexibility for a variety of different situations, which can include the following:

Equipment positioning.

Measure the material level of the package.

Measure the distance and height of objects on the conveyor.

Measure the diameter of logs.

Protect the overhead crane from collision.

No error checking occasions.

Monitor the distance of the aircraft from the ground.

The basic composition of a laser ranging sensor is a measurement result display system for a laser, an imaging objective, a photopotential receiver, and a signal processor. The laser beam forms a bright spot on the surface of the object to be measured, and the imaging objective lens images the spot onto the photosensitive of the photosensitive receiver, and generates an electrical signal that detects the location of the spot on its sensitive surface. When the measured object moves, the position of the spot on the surface relative to the imaging objective lens changes, and the position of the imaging point on the photosensitive device changes accordingly. The light reflected by the target passes through the receiving lens group and is focused on the CCD and sensor. Use the light amount distribution of all light spots on the CCD to determine the center of the light spot, and use this as the target position. The CCD detects the peak value of the light amount distribution of each pixel and recognizes it as the position of the target. Regardless of the light amount distribution of the light point, the CCD can perform stable and high-precision displacement measurement.

Laser parameters

Laser characteristics: red laser diode;

Wavelength: 635nm;

Laser level: 2 levels;

Light spot type: point;

Light spot size: about 2mm in diameter;

Output power: less than 1mW;

Model LMG3001P LMG5005P LMG8015P

45-70mm 50-150mm 50-200mm

Resolution 20m 50m 100m

Sampling frequency 1.2KHz 1.2KHz 1.2KHz

Non-linearity <0.1% <0.1% <0.1%