Target Displacement Measurement Method And System Design Based On Laser Triangulation

In recent years,with the continuous and rapid development of industrial testing technology,non-contact laser measurement technology has been widely used in the field of measurement due to its non-destructive testing,real-time performance,and good accuracy.For application measurement environments such as product quality inspection,equipment monitoring,and track change gauge detection on industrial production lines,there are measurement requirements such as long measurement ranges and multi node laying.High precision laser triangular displacement sensor equipment has a small measurement range,while high precision and large measurement range laser triangular displacement sensor equipment has shortcomings such as complex optical path and high price,which does not meet the requirements of large-scale deployment of equipment.Based on laser triangulation ranging technology,this paper designs a low-cost laser triangulation displacement measurement system with medium and long distance measurement range,large range,submillimeter measurement accuracy,and multiple working modes,aiming at the above application measurement environment and requirements.The following design and research are carried out in this paper:1.Firstly,the mathematical model of the direct beam laser triangulation method is constructed.By changing the arrangement angle of the CCD and optical lens,the displacement measurement range is increased while ensuring the expected theoretical resolution,and relevant system parameters are analyzed.High resolution displacement measurement at a distance of 600 mm to 800 mm can be achieved.According to the requirements for the pixel width and number of linear array CCD based on the light spot width,system resolution,and measurement range,the CCD sensor selection is completed.At the same time,in order to improve the receiving range of the longitudinal optical signal of the linear array CCD sensor and reduce the measurement error caused by the longitudinal deviation of the light spot imaging,a cylindrical lens is selected for light spot imaging.2.Secondly,three working modes,namely,single real-time measurement,periodic state monitoring measurement,and combined frame high-precision fast storage measurement,are designed.The impact of optical speckle noise on the positioning of the spot imaging center during the operation of the photoelectric sensor is analyzed,resulting in a decrease in measurement accuracy.Therefore,a combined frame data acquisition method is proposed to suppress optical speckle noise to reduce measurement errors,At the same time,the ping-pong buffer mechanism is introduced for data flow control to achieve seamless buffering and processing of data.3.Finally,the sensor output data is smoothed and blurred before processing.At the same time,the positioning methods of the spot imaging center in various photoelectric sensors are analyzed.The centroid method is selected as the positioning algorithm,and the adaptive threshold centroid method and Gaussian fitting method are combined to perform subpixel positioning of the spot imaging center.A system testing scheme is designed for system performance testing,various factors that cause system measurement errors are analyzed,and system improvement measures are proposed.After testing,the standard displacement measurement system can perform sub millimeter precision multi mode measurement in the medium to long distance range of 600 mm to800mm,realizing a precise and practical displacement measurement system with controllable cost,complete functions,and wide application range.