Distortion is a technical indicator in the field of voice signal processing. The design is a portable distortion degree tester, based on Field-Progranmmble Gate Array （FleA, EP2C20） as the cote, using harmonic analy...Distortion is a technical indicator in the field of voice signal processing. The design is a portable distortion degree tester, based on Field-Progranmmble Gate Array （FleA, EP2C20） as the cote, using harmonic analysis method which better solve the distortion problem of acctwacy. It can achieve the signal transformation from the time-domain to the frequency-donkain, and is widely used for signal spectrum analysis. All the componets used in the design are low power, high perf-, low drift and industrial grade compionents. The reference voltage sources of ADC and DAC have identical performance of high stability, high precision. The dtr.k is the precise stable clock with FPGA temperature compensation. This project can get the cost-effective, high-precision, low power and portable design goals.展开更多
A lack of accurate description of the meshing characteristics and the corresponding frictional mechanism of the harmonic drive gear has limited progress toward modeling the hysteresis stiffness. This paper presents a ...A lack of accurate description of the meshing characteristics and the corresponding frictional mechanism of the harmonic drive gear has limited progress toward modeling the hysteresis stiffness. This paper presents a method for detection and quantification of the meshing characteristics of the harmonic drive gear based on computer vision. First, an experimental set-up that integrates a high speed camera system with a lighting system is developed, and the image processing is adopted to extract and polish the tooth profiles of the meshed teeth pairs in each acquired video sequence. Next, a physical-mathematical model is established to determine the relative positions of the selected tooth pair in the process of the gear engagement, and the combined standard uncertainty is utilized to evaluate the accuracy of the calculated kinematics parameters. Last, the kinematics analysis of the gear engagement under the ultra-low speed condition is performed with our method and previous method, and the influence of the input rotational speed on the results is examined. The results validate the effectiveness of our method, and indicate that the conventional method is not available in the future friction analysis. It is also shown that the engaging-in phase is approximately a uniform motion process, the engaging-out phase is a variable motion process, and these characteristics remain unchanged with the variation of the input rotational speed. Our method affords the ability to understand the frictional mechanism on the meshed contact surfaces of the harmonic drive gear, and also allows for the dynamic monitoring of the meshing properties.展开更多
文摘Distortion is a technical indicator in the field of voice signal processing. The design is a portable distortion degree tester, based on Field-Progranmmble Gate Array （FleA, EP2C20） as the cote, using harmonic analysis method which better solve the distortion problem of acctwacy. It can achieve the signal transformation from the time-domain to the frequency-donkain, and is widely used for signal spectrum analysis. All the componets used in the design are low power, high perf-, low drift and industrial grade compionents. The reference voltage sources of ADC and DAC have identical performance of high stability, high precision. The dtr.k is the precise stable clock with FPGA temperature compensation. This project can get the cost-effective, high-precision, low power and portable design goals.
基金supported by the National Natural Science Foundation of China(Grant No.11272171)the Beijing Natural Science Foundation(Grant No.3132030)the Education Ministry Doctoral Fund of China(Grant No.20120002110070)
文摘A lack of accurate description of the meshing characteristics and the corresponding frictional mechanism of the harmonic drive gear has limited progress toward modeling the hysteresis stiffness. This paper presents a method for detection and quantification of the meshing characteristics of the harmonic drive gear based on computer vision. First, an experimental set-up that integrates a high speed camera system with a lighting system is developed, and the image processing is adopted to extract and polish the tooth profiles of the meshed teeth pairs in each acquired video sequence. Next, a physical-mathematical model is established to determine the relative positions of the selected tooth pair in the process of the gear engagement, and the combined standard uncertainty is utilized to evaluate the accuracy of the calculated kinematics parameters. Last, the kinematics analysis of the gear engagement under the ultra-low speed condition is performed with our method and previous method, and the influence of the input rotational speed on the results is examined. The results validate the effectiveness of our method, and indicate that the conventional method is not available in the future friction analysis. It is also shown that the engaging-in phase is approximately a uniform motion process, the engaging-out phase is a variable motion process, and these characteristics remain unchanged with the variation of the input rotational speed. Our method affords the ability to understand the frictional mechanism on the meshed contact surfaces of the harmonic drive gear, and also allows for the dynamic monitoring of the meshing properties.
