Research Of Laser Triangulation Measurement Sensor Based On DSP

With the appearance of new material and the improvement of manufacture accuracy, some difficulties appear in measuring minor-sized work piece or flexible and fragile work piece with contact probe. As a new non-contacted displacement sensor, Laser displacement sensor based on triangulation has many excellent advantages such as being simple structure, high-speed measurement and high precision, small test spot, good anti-jamming ability, non-contact measurement, so laser displacement sensor based on triangulation is of great value and enjoys broad application prospects in industry-manufacture field such as machine vision, auto-machining, online measurement, practicality profile modeling biomedicine.In practice applications, there are some question that is not resolved, such as non-linear error, dispel speckle influence, surface incline, surface characteristic change, low responding speed, circumstance restrict. One or some those questions will arouse the system error.This paper investigates the influence factors from fundamental reason, with certain quantity and uncertain quantity. Put forward betterment project, and design the DSP system hardware and software, the main work is list next:1. By the analyses and comparisons, the author decided to design the triangulation system for a normal incidence type. The diode-laser is chose to be the light and the high accurate linear CCD imaging sensor was used as the receiver. Base on system technical demand, calculate and select optics parameter. With the most possibility, use the most object, for improve measuring precision.2. Use average filter and the improved middle filter to treat the original images collected by CDD in order to gain more stable signals; analyze how to enhance the CDD resolution by calculating the data which are collected on the CDD surface so that every method to enhance the measurement precision of the distance-measurement sensor is improved; analyze both the advantages and disadvantages of such wonderful methods as probability method, demodulation method,center of gravity method,polynomial interpolation method,polynomial fitting which can increase the CDD resolution. On the basis of these methods, squared gravity method is put forth.3. Propose an approach to adaptive controller for laser power, use FPGA control and adjust the current of the laser. This method can measure and check the surface of subject, and adjust the laser power to optimal status. Design drive circuit and it can drive laser stably.4. Including AD collection circuit matching with CCD, solve the interface between slow component and high speed component by FPGA, design display and memory extend and resist disturb.5. By the electric parameter and measuring environment and processing arithmetic. Design a system of soft distance measuring with TMS320VC5509A, based on thread model CCD, and complete system software function.6. Based on the principle of trigonometry measuring, research the factors of influence measuring precision. Analyzing main factors form the influence causation angles. And above this find resolve scheme. Minis circumstance change and parameter error influence.