The Portable Fourier Transform Infrared Spectrometer Based On Cortex-M4

Infrared spectroscopy technology is constantly open up and innovation.Research institutions at home and abroad are competing to research in the field of Fourier transform infrared spectroscopy equipment.Compared with the domestic Fourier infrared spectroscopy technology development,foreign instrument research and development are more advanced in the core technical level.Under such conditions,the research and development of precision instruments in the country is dependent on long-term imports from abroad.The performance parameters of foreign precision instruments with fast detection and high accuracy are good,but they are expensive.Importing of advanced equipment is expensive and it not conducive to the development of domestic equipment industry technology.At the same time,the traditional Fourier infrared spectrometer volume also depends on the laboratory stability of the measurement environment,although the resolution can be very high,it is difficult to get out of the laboratory.At present,the development of Fourier infrared spectrometer is also more and more inclined to its portability,which can leave the laboratory environment for the relevant measurements.Under such conditions,the Portable Fourier Transform Infrared Spectrometer Based on Cortex-M4 was designed in order to achieve a breakthrough in the domestic technical level.The instrument uses a dual optical path of the Michelson interferometer in the design structure.Fixed and moving mirror use corner mirror instead of the traditional plane mirror.The deflection of the apex of the cube-corner and the deflection of the moving position do not increase the extra optical path difference,so there is no need for dynamic adjustment to simplify the design and control of the instrument.In the design of the optical path using 60° interference optical path,not only reducing the structural volume but also improving the optical efficiency.At the same time,the optical path of the combination of the corner mirror and the plane mirror doubles the optical path difference compared to the traditional reflected light path,so that the instrument can achieve higher resolution.The design of the moving mirror mechanism adopts the flexible hinge support and the voice coil motor.It overcome the impact of friction and large volume of the traditional supporting mechanism,making the instrument with a certain degree of seismic capacity.At the same time,the dynamic verticality error analysis is carried out for the moving mirror mechanism.Article Indicate its influence on the modulation degree of the signal and the initial phase and find a way to optimization to reduce its error in the design.The motion control mechanism adopts the discrete PID algorithm and combines the compensation of the elastic force parameter and the zero offset parameter.The overall design of moving mirror mechanism has a high stability and anti-interference ability.The reference laser source of the spectrometer uses a 680nm VCSEL.It has high luminous intensity,low light source noise,narrow spectral line width and small volume.It can replace the traditional large volume He-Ne laser.The infrared detector uses DTGS instead of MCT and does not require additional cooling.The selection of light source and detector are consistent with the design of portable instruments.The design of the analog circuit and the selection of the chip are careful to reduce the noise interference.So a high-band bandpass filter was designed.The control processor uses the ARMCortex-M4,which with rich resources,high-performance 32-bit CPU,low power consumption,fast response and low delay.The CPLD uses the periodicity method to complete the frequency calculation of the laser interference signal.CPLD with ARM to complete the motion control system and infrared light data sampling processing.Infrared interference signal data using one-way bilateral acquisition mode,and the data is a one-way collection of unidirectional transmission,reducing data conflict also improving the efficiency of data processing.Experiments show that the Portable Fourier Transform Infrared Spectrometer Based on Cortex-M4 have characteristics with the measurement of high sensitivity,fast response,high resolution and high signal to noise ratio.Signal acquisition is highly reproducible and accurate,and the stability of the system has a good anti-interference ability,which meet the requirements of portable Fourier transform infrared spectrometer.