LIBS Object Sorting with Dynamic Laser Tracking
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Solution Overview
Problem
Existing LIBS-type object sorting devices face challenges in accurately performing LIBS analysis on objects with intricate shapes, as they require precise three-dimensional spatial information and movement consideration, limiting the processing capacity of objects with complex surfaces.
Innovation Solution
The device employs a three-dimensional-shape measurement system to repeatedly measure the cross-sectional shape of objects, a LIBS analyzing system that moves the laser beam in both width and height directions, and a conveying-path switching mechanism, along with a control system to determine the optimal analysis section and adjust the beam position, enabling accurate chemical composition analysis and sorting of objects on a conveyor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser range finder is used to measure the contour of objects on a conveyor, then the height direction cross-section can be measured, but only one object can be measured at a time and the processing capacity is limited
Solution Approach 1:
The patent transitions from one-dimensional (single-point) laser range finding to two-dimensional laser line projection. By projecting a laser line across the conveyor width and capturing it with a line sensor, the system measures multiple points simultaneously, enabling parallel measurement of multiple objects while maintaining height measurement accuracy.
Solution Approach 2:
The patent combines the laser projection function and the measurement function into a single integrated system. The laser projector projects lines across the conveyor while the line sensor captures the reflected light pattern, merging multiple measurement functions into one coordinated system that processes multiple objects simultaneously.
2Reliability
If condensing irradiation with pulse laser light is performed on objects with intricate shapes, then LIBS analysis can be achieved, but precise three-dimensional spatial information and accurate positioning are required, increasing system complexity
Solution Approach 1:
The patent implements a feedback control system where the measured three-dimensional spatial information of objects is used to dynamically adjust the laser beam positioning. The system continuously monitors object position and shape, then feeds this information back to the laser control system to maintain accurate irradiation positioning despite object movement and shape variations.
Solution Approach 2:
The patent performs preliminary measurement of the object's three-dimensional shape and position before the actual LIBS analysis. This preliminary spatial information is used to pre-calculate and pre-position the optimal laser irradiation points, ensuring that when the laser fires, it is already positioned accurately on the object surface without requiring complex real-time adjustments during the analysis itself.
3Device complexity
If the laser beam position is fixed while the conveyor moves at high speed, then the system is simple, but the laser cannot accurately track objects with movement, reducing measurement accuracy
Solution Approach 1:
The patent transforms the static laser beam positioning system into a dynamic one that can adapt to moving objects. The beam positioning system continuously adjusts its position based on real-time object location data, allowing the laser to track and maintain accurate irradiation on objects moving along the conveyor at high speed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for high-accuracy sorting of objects with intricate shapes at high speeds, achieving a high signal-to-noise ratio and enabling the processing of multiple objects alongside each other on the conveyor belt.
Implementation Method 1
Laser induced breakdown spectroscopy (LIBS) is a qualitative and quantitative analysis method of an element contained in an object to be measured. Specifically, condensing irradiation of a fine spot on the surface of an object with pulse laser light, instantaneously separates atoms into ions and electrons, to make a plasma state.
Implementation Method 2
An object moving on a conveyor is scanned with a laser projector (linear laser light source) and movement in the height direction of reflected light (emission line) varying in response to a surface shape, is captured at certain intervals
Data Source
AI summary
An LIBS-type object sorting device includes a three-dimensional-shape measurement means that acquires a space-coordinate group of a top face of an object to be sorted in top view on a conveyor, an LIBS analyzing means that performs chemical composition analysis on the object to be sorted while irradiating the object to be sorted with laser light, and a conveying-path switching means that switches a conveying path of the object to be sorted, in this order. The device includes a computing means that determines an analyzing section on which the LIBS analysis is to be performed, and a control means that causes a beam position to move and causes, when detecting that the analyzing section has reached from a movement amount of the conveyor, based on the movement amount, a beam-focus position to move along the analyzing section while irradiating the laser light.