Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed a...Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed are the mixture of these three colours. Consequently these devices can be confusing in testing human color identification, because the spectral distribution of the colors displayed is the combined spectrum of the three primaries. We have developed a new instrument for spectrally correct color vision measurement. This instrument uses light emitting diodes (LEDs) and is capable of producing all spectra of perceivable colors, thus with appropriate test methods this instrument can be a reliable and useful tool in test~ing human color vision and in verifying color vision correction.展开更多
Typical multidisciplinary design optimization（MDO） has gradually been proposed to balance performances of lightweight, noise, vibration and harshness（NVH） and safety for instrument panel（IP） structure in the aut...Typical multidisciplinary design optimization（MDO） has gradually been proposed to balance performances of lightweight, noise, vibration and harshness（NVH） and safety for instrument panel（IP） structure in the automotive development. Nevertheless, plastic constitutive relation of Polypropylene（PP） under different strain rates, has not been taken into consideration in current reliability-based and collaborative IP MDO design. In this paper, based on tensile test under different strain rates, the constitutive relation of Polypropylene material is studied. Impact simulation tests for head and knee bolster are carried out to meet the regulation of FMVSS 201 and FMVSS 208, respectively. NVH analysis is performed to obtain mainly the natural frequencies and corresponding mode shapes, while the crashworthiness analysis is employed to examine the crash behavior of IP structure. With the consideration of lightweight, NVH, head and knee bolster impact performance, design of experiment（DOE）, response surface model（RSM）, and collaborative optimization（CO） are applied to realize the determined and reliability-based optimizations, respectively. Furthermore, based on multi-objective genetic algorithm（MOGA）, the optimal Pareto sets are completed to solve the multi-objective optimization（MOO） problem. The proposed research ensures the smoothness of Pareto set, enhances the ability of engineers to make a comprehensive decision about multi-objectives and choose the optimal design, and improves the quality and efficiency of MDO.展开更多
Tubular hydroforming has attracted increased attention in the vehicle industry recently. This paper covers a complete hydroforming process design for an instrum ent panel frame by finite element simulation using the e...Tubular hydroforming has attracted increased attention in the vehicle industry recently. This paper covers a complete hydroforming process design for an instrum ent panel frame by finite element simulation using the explicit code LS-DYNA. The manufacturing process for the instrument panel frame consists of tube pre-be nding and final hydroforming. To accomplish hydroforming process design successf ully, a thorough investigation of proper combination of process parameters such as internal hydraulic pressure and axial feeding is carried out by finite element simulation to predict the tube wall thickness and shape. An optimized process parameter combination is obtained and verified by the instrument panel frame hyd roforming experiment. The experiment shows that designed process parameters can be used in real production through FEA simulation, but tubular thinned amplitu de by FEA is less than that with the experiment.展开更多
Tick-mark recognition is a key step for automatic reading of analog instrument with computer vision techniques which is called for in many automatic processes among industries. As many factors result in the tick-mark ...Tick-mark recognition is a key step for automatic reading of analog instrument with computer vision techniques which is called for in many automatic processes among industries. As many factors result in the tick-mark distortion in the sampled image such as the generally stained surface of instrument, or/and reflection and refraction of light, the accuracy and robustness of tick-mark reading are directly or indirectly weakened. Double image segmentation algorithm (DISA) is employed to solve this problem which make</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> coarse segmentation with structural parameters of instruments, and make</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> accurate segmentation with gray difference between tick-marks and their background. Tests have been conducted with 640 * 480 pixel industry camera and 4 kinds of pointer pressure meter, and the results show that read-out rate of tick-mark in pointer meter reached 100% at sufficient illumination and 76% at insufficient illumination for air packed instrument. In addition with oil packed instrument, DISA still experienced 64% recognition in comparison with 0 success record by Hough Transformation.展开更多
文摘Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that they work with three primaries and the colors displayed are the mixture of these three colours. Consequently these devices can be confusing in testing human color identification, because the spectral distribution of the colors displayed is the combined spectrum of the three primaries. We have developed a new instrument for spectrally correct color vision measurement. This instrument uses light emitting diodes (LEDs) and is capable of producing all spectra of perceivable colors, thus with appropriate test methods this instrument can be a reliable and useful tool in test~ing human color vision and in verifying color vision correction.
基金supported by National Hi-tech Research and Development Program of China(863 Program, Grant No. 2007AA04Z132)National Natural Science Foundation of China(Grant No. 51175379)
文摘Typical multidisciplinary design optimization（MDO） has gradually been proposed to balance performances of lightweight, noise, vibration and harshness（NVH） and safety for instrument panel（IP） structure in the automotive development. Nevertheless, plastic constitutive relation of Polypropylene（PP） under different strain rates, has not been taken into consideration in current reliability-based and collaborative IP MDO design. In this paper, based on tensile test under different strain rates, the constitutive relation of Polypropylene material is studied. Impact simulation tests for head and knee bolster are carried out to meet the regulation of FMVSS 201 and FMVSS 208, respectively. NVH analysis is performed to obtain mainly the natural frequencies and corresponding mode shapes, while the crashworthiness analysis is employed to examine the crash behavior of IP structure. With the consideration of lightweight, NVH, head and knee bolster impact performance, design of experiment（DOE）, response surface model（RSM）, and collaborative optimization（CO） are applied to realize the determined and reliability-based optimizations, respectively. Furthermore, based on multi-objective genetic algorithm（MOGA）, the optimal Pareto sets are completed to solve the multi-objective optimization（MOO） problem. The proposed research ensures the smoothness of Pareto set, enhances the ability of engineers to make a comprehensive decision about multi-objectives and choose the optimal design, and improves the quality and efficiency of MDO.
文摘Tubular hydroforming has attracted increased attention in the vehicle industry recently. This paper covers a complete hydroforming process design for an instrum ent panel frame by finite element simulation using the explicit code LS-DYNA. The manufacturing process for the instrument panel frame consists of tube pre-be nding and final hydroforming. To accomplish hydroforming process design successf ully, a thorough investigation of proper combination of process parameters such as internal hydraulic pressure and axial feeding is carried out by finite element simulation to predict the tube wall thickness and shape. An optimized process parameter combination is obtained and verified by the instrument panel frame hyd roforming experiment. The experiment shows that designed process parameters can be used in real production through FEA simulation, but tubular thinned amplitu de by FEA is less than that with the experiment.
文摘Tick-mark recognition is a key step for automatic reading of analog instrument with computer vision techniques which is called for in many automatic processes among industries. As many factors result in the tick-mark distortion in the sampled image such as the generally stained surface of instrument, or/and reflection and refraction of light, the accuracy and robustness of tick-mark reading are directly or indirectly weakened. Double image segmentation algorithm (DISA) is employed to solve this problem which make</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> coarse segmentation with structural parameters of instruments, and make</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> accurate segmentation with gray difference between tick-marks and their background. Tests have been conducted with 640 * 480 pixel industry camera and 4 kinds of pointer pressure meter, and the results show that read-out rate of tick-mark in pointer meter reached 100% at sufficient illumination and 76% at insufficient illumination for air packed instrument. In addition with oil packed instrument, DISA still experienced 64% recognition in comparison with 0 success record by Hough Transformation.
