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Protecting the hydroforming die The manipulator puts a preformed tube into the lower die of the hydroforming machine, and the operator must ensure that the placement is accurate each time. A diverging sensor measures the distance to the critical section of the tube before the upper die is dropped, which ensures that the die is in the correct position before closing.
When the laser ranging sensor works through the transit time laser sensor, the laser diode is first 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. Transit time Laser sensors must measure transit time extremely precisely because the speed of light is so fast. For example, the speed of light is about 3’108m/s. To achieve a resolution of 1mm, the electronic circuit of the transit time ranging sensor must be able to distinguish the following extremely short times: 0.001m, (3’108m/s)=3ps To distinguish the time of 3ps, this is a high requirement for electronic technology, and the cost is too high to realize. But today’s inexpensive transit-time laser sensors neatly circumvent this obstacle, using a simple statistical principle, the law of averaging, to achieve a resolution of 1mm with guaranteed responsiveness.
Several application examples of laser ranging sensors
1. To measure the width of the boxes on the conveyor belt, two divergent transit time laser sensors are used, which are installed face to face on both sides of the conveyor belt. Because the position of the box that changes in size falls on the conveyor belt is not fixed, so each sensor measures the distance between itself and the box, and sets one distance as L1 and the other as L2. This information is sent to the PLC, which subtracts L1 and L2 from the total distance between the two sensors to calculate the width W of the box.
2. Protecting the hydraulic forming die The manipulator puts a preformed pipe into the lower die of the hydroforming machine, and the operator must ensure that the position is accurate each time. A diverging sensor measures the distance to the critical section of the tube before the upper die is dropped, which ensures that the die is in the correct position before closing.
3. Two-axis crane positioning is installed with two reflective sensors facing the reflector, and the reflector is installed on the two mobile units of the bridge crane. One unit moves back and forth and the other moves side to side. When the crane drives the pallet rollers, two sensors monitor their respective distances to the reflector, and the precise position of the crane can be continuously tracked through the PLC.
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