Laser ranging sensor: First, the laser diode is aimed at the target to emit laser pulses. After being reflected by the target, the laser light is scattered in all directions. Part of the scattered light returns to the sensor receiver, where it is picked up by the optical system and imaged onto the avalanche photodiode. An avalanche photodiode is an optical sensor with an internal amplification function, so it can detect extremely weak light signals. The distance to the target can be determined by recording and processing the time elapsed from when the light pulse is sent to when it is received back.
According to the measurement frequency, it can be divided into: ZYT-0100-1 10Hz RS232/RS422; ZYT-0100-2 50Hz RS232/RS422; ZYT-405 50Hz This type is a regional ranging detection control sensor; it outputs switch value or level signal.
Laser ranging sensor technology is divided into absolute distance measurement method and micro-displacement measurement method according to the range. According to the subdivision of ranging methods, the absolute distance ranging method mainly includes pulse laser ranging and phase laser ranging, and the micro-displacement measuring method mainly includes triangulation laser ranging and interferometric laser ranging.
The principle of the pulsed laser ranging sensor is: a pulsed laser with a very short duration is emitted by a pulsed laser. After passing the distance to be measured, it hits the measured target, and a part of the energy will be reflected back. The reflected pulsed laser is called an echo. . The echo returns to the rangefinder and is received by a photodetector. According to the interval between the main wave signal and the echo signal, that is, when the laser pulse travels back and forth from the laser to the target to be measured, the distance to the target to be measured can be calculated.
The principle of the phase laser ranging sensor is to modulate the intensity of the emitted laser light, and use the phase change of the modulated signal when the laser propagates in space. From the wavelength of the modulated wave, the distance represented by this phase delay is calculated. That is, the indirect method of phase delay measurement is used to replace the direct measurement of the time required for the laser round-trip to achieve distance measurement. The accuracy of this method can reach the millimeter level.
The triangulation laser ranging sensor is the light emitted by the laser, which is focused by the converging lens and then incident on the surface of the object to be measured. The receiving lens receives the scattered light from the incident light point and images it on the sensitive surface of the photoelectric position detector. . When the object moves, the relative distance that the object moves is calculated by the displacement of the light spot on the imaging surface. The resolution of triangulation laser ranging is very high, which can reach the order of micrometers.
The interferometric laser ranging sensor moves the measured target and measures the coherence, and completes the measurement of the distance increment by counting, so the sensitivity of the interferometric measurement is very high, which can reach the nanometer level.
