A new acoustic barrier structure with resonant sound of micro-perforation board absorption structure and impedance composite sound-absorption structure is proposed.The acoustic impedance and the sound-absorption coeff...A new acoustic barrier structure with resonant sound of micro-perforation board absorption structure and impedance composite sound-absorption structure is proposed.The acoustic impedance and the sound-absorption coefficient of the acoustic structure are calculated via means of equivalent circuit.MATLAB is used to calculate the relationship between the parameters of the ontology structure and the sound-absorption coefficient and the sound insulation.It is revealed that the sound barrier of the new ontology structure is 7.659.80 dB,which is more than the sound barrier of the traditional reflective structures.The relationships among the parameters of sound-absorption structure,sound-absorption coefficient,and sound insulation performance are obtained.In addition,the parameters can be transformed to satisfy the noise reduction requirements of various road sections,which has a admirable adaptability.The acoustic barrier can have tremendous acoustic performance only if there is a splendid sound insulation in the traffic noise frequency band.展开更多
The theory of active absorption of the perforated plate is proposed in this paper.The perforated plate is used as the material of active absorption and the depth of the cavity behind the perforated plate is changed ac...The theory of active absorption of the perforated plate is proposed in this paper.The perforated plate is used as the material of active absorption and the depth of the cavity behind the perforated plate is changed according to the resonant frequency of the perforated plate.The rigid wall is moved to produce resonance so that the absorption coefficient can reach the maximal level.It is shown from the numerical calculation that when the perforated plate resonates,the moving distance is large at low frequencies,and the absorption coefficient is low under certain conditions.Perforated plate resonance is effective for single frequency of incident sound wave,which is difficult for the wide frequency,so active absorption based on airflow is posed,and the numerical calculation and experiment are carried out.The results denote that this method of active absorption is practical.展开更多
The multilayer impedance composite sound absorption structure of the new muffler is proposed by combining the microporous plate structure with the resonant sound absorption structure of the porous material.Firstly,the...The multilayer impedance composite sound absorption structure of the new muffler is proposed by combining the microporous plate structure with the resonant sound absorption structure of the porous material.Firstly,the acoustic impedance and acoustic absorption coefficient of the new muffler structure are calculated by acoustic electric analogy method,and then the noise attenuation is calculated.When the new muffler structure parameters change,the relationship among the noise frequency,the sound absorption coefficient and the noise attenuation is calculated by using MATLAB.Finally,the calculated results are compared with the experimental data to verify the correctness of the theoretical calculation.The variation of resonance peak,resonance frequency and attenuation band width of each structural parameter is analyzed by the relation curve.The conclusion shows that it is feasible to use multilayer sound absorbing materials as the body structure of the new muffler.And the influence relationship between the change of various parameters of the sound absorption structure with the sound absorption coefficient and noise attenuation is obtained.展开更多
The high-pressure electro-pneumatic servo valve(HESV)is a core element of the high-pressure pneumatic servo system.The annular clearance and the rounded corner of the spool-sleeve can cause the leakage at null positio...The high-pressure electro-pneumatic servo valve(HESV)is a core element of the high-pressure pneumatic servo system.The annular clearance and the rounded corner of the spool-sleeve can cause the leakage at null position,thereby affecting high-precision control and stability of the servo system.This paper investigates the effects of the clearance structure on leakage behavior at null position of the HESV.A numerical approach was employed to evaluate the effects,and then a mathematical model was established to obtain the variation law of leakage flow rate at null position.The results indicate that the leakage flow rate at null position varies linearly with supply pressure and rounded corner radius,and is nonlinear as a quadratic concave function with annular clearance.The leakage flow rate of the annular clearance and the rounded corner varies with the valve opening in an invariable−nonlinear−linear trend.A test rig system of leakage behavior at null position of the HESV was built to confirm the validity of the numerical model,which agrees well with the conducted experimental study.展开更多
A tolerance modeling method of geometric variations within three-dimensional(3D) tolerance domain is proposed.According to the classification method of feature variations and classes of invariance or symmetry in the n...A tolerance modeling method of geometric variations within three-dimensional(3D) tolerance domain is proposed.According to the classification method of feature variations and classes of invariance or symmetry in the new generation Geometrical Product Specifications(GPS) system,the proposed method is based on the Small Displacement Torsor(SDT) concept,and SDT is used to represent the geometric deviations between the nominal feature and the fitting feature. Furthermore,the variation zones of several kinds complex or irregular geometric features are constructed,and the corresponding tolerance modeling methods are discussed respectively. Finally,an example is presented to verify the efficiency of the presented method for modeling 3D dimensional and geometrical tolerances.The proposed modeling method based on the complete mathematical foundation conforms with the design philosophy and principle of the new generation GPS standards system.展开更多
The sound characteristic of the piezoelectric ceramics is posed for the excellent mechanic and electric coupling performance of piezoelectric material.Two pieces of piezoelectric ceramic are used as materials of activ...The sound characteristic of the piezoelectric ceramics is posed for the excellent mechanic and electric coupling performance of piezoelectric material.Two pieces of piezoelectric ceramic are used as materials of active absorption and active isolation,two pieces of PVDF with equal distance are placed in the front of the material in order to measure the incidence plane wave and the reflected wave,the voltages are applied on the surface of the material in order to make the reflected wave and transmission wave be zero using the adaptive controlling.At last,emulation is carried out with plane wave,and good absorption and isolation effect is achieved.展开更多
In the field of engineering,LabVIEW and MATLAB are the languages most commonly used by program developers.Howev-er,they have their respective advantages and disadvantages.The combination of the two will undoubtedly fa...In the field of engineering,LabVIEW and MATLAB are the languages most commonly used by program developers.Howev-er,they have their respective advantages and disadvantages.The combination of the two will undoubtedly facilitate program develop-ment.Design of inference engine is the key point and difficulty in the design of fault diagnosis expert system.This paper combinesLabVIEW and MATLAB to design the inference engine of fault diagnosis expert system based on the advantages of the graphical pro-gramming environment and signal analysis toolkit of LabVIEW without the defect of neural network toolkit.In addition,it introducesthe implementation methods and precautions for combination of LabVIEW and BP network so as to make LabVIWE amd BP benefitfrom each other,which is of great pragmatic value.展开更多
Anomaly Detection (AD) has been extensively adopted in industrial settings to facilitate quality control of products. It is critical to industrial production, especially to areas such as aircraft manufacturing, which ...Anomaly Detection (AD) has been extensively adopted in industrial settings to facilitate quality control of products. It is critical to industrial production, especially to areas such as aircraft manufacturing, which require strict part qualification rates. Although being more efficient and practical, few-shot AD has not been well explored. The existing AD methods only extract features in a single frequency while defects exist in multiple frequency domains. Moreover, current methods have not fully leveraged the few-shot support samples to extract input-related normal patterns. To address these issues, we propose an industrial few-shot AD method, Feature Extender for Anomaly Detection (FEAD), which extracts normal patterns in multiple frequency domains from few-shot samples under the guidance of the input sample. Firstly, to achieve better coverage of normal patterns in the input sample, we introduce a Sample-Conditioned Transformation Module (SCTM), which transforms support features under the guidance of the input sample to obtain extra normal patterns. Secondly, to effectively distinguish and localize anomaly patterns in multiple frequency domains, we devise an Adaptive Descriptor Construction Module (ADCM) to build and select pattern descriptors in a series of frequencies adaptively. Finally, an auxiliary task for SCTM is designed to ensure the diversity of transformations and include more normal patterns into support features. Extensive experiments on two widely used industrial AD datasets (MVTec-AD and VisA) demonstrate the effectiveness of the proposed FEAD.展开更多
Design automation is a core technology in industrial design software and an important branch of knowledge-worker automation.For example,electronic design automation(EDA)has played an important role in both academia an...Design automation is a core technology in industrial design software and an important branch of knowledge-worker automation.For example,electronic design automation(EDA)has played an important role in both academia and industry.Design automation for intelligent robots refers to the construction of unified modular graph models for the morphologies(body),controllers(brain),and vision systems(eye)of intelligent robots under digital twin architectures,which effectively supports the automation of the morphology,controller,and vision system design processes of intelligent robots by taking advantage of the powerful capabilities of genetic programming,evolutionary computation,deep learning,reinforcement learning,and causal reasoning in model representation,optimization,perception,decision making,and reasoning.Compared with traditional design methods,MOdular DEsigN Automation(MODENA)methods can significantly improve the design efficiency and performance of robots,effectively avoiding the repetitive trial-and-error processes of traditional design methods,and promoting automatic discovery of innovative designs.Thus,it is of considerable research significance to study MODENA methods for intelligent robots.To this end,this paper provides a systematic and comprehensive overview of applying MODENA in intelligent robots,analyzes the current problems and challenges in thefield,and provides an outlook for future research.First,the design automation for the robot morphologies and controllers is reviewed,individually,with automated design of control strategies for swarm robots also discussed,which has emerged as a prominent research focus recently.Next,the integrated design automation of both the morphologies and controllers for robotic systems is presented.Then,the design automation of the vision systems of intelligent robots is summarized when vision systems have become one of the most important modules for intelligent robotic systems.Then,the future research trends of integrated“Body-Brain-Eye”design automation for intelligent robots are discussed.Finally,the common key technologies,research challenges and opportunities in MODENA for intelligent robots are summarized.展开更多
In this paper,an angular position sensor(APS)designed for a resonant miniaturized scanning mirror(M-SM)is presented.The APS operates based on the principle of differential variable capacitance,significantly expanding ...In this paper,an angular position sensor(APS)designed for a resonant miniaturized scanning mirror(M-SM)is presented.The APS operates based on the principle of differential variable capacitance,significantly expanding the detectable bandwidth from a few hertz to several kilohertz.By modeling the motion characteristics,the sampling rates of the biaxial scanning angles are 1473.6 times and 539.4 times higher than those of conventional sensors.Initially,the motion characteristics model is presented as a simple harmonic motion,converting sampled capacitance into continuous capacitance.Subsequently,the nonparallel state of the M-SM and sensor is transformed into a parallel state through the space coordinate system transformation.Furthermore,a 2D nonlinear angle transfer function is developed to convert the differential capacitance into an angle,thereby mitigating the nonlinear errors resulting from large angles.Achieving an accuracy better than 0.014°,the measuring range expands from±0.5729°(±10 mrad)to±5.026°(±87 mrad).Additionally,the capturing mode and tracking mode are proposed to monitor real-time angular changes of the M-SM with an accuracy of 0.017°.High-precision APSs have enhanced beam pointing accuracy and resolution and can thereby be used to advance the development of laser components,including light detection and ranging(LiDAR).展开更多
基金National Natural Science Foundation of China(No.51175195)Guiding Plan of Textile Industry Federation,China(No.2017053)
文摘A new acoustic barrier structure with resonant sound of micro-perforation board absorption structure and impedance composite sound-absorption structure is proposed.The acoustic impedance and the sound-absorption coefficient of the acoustic structure are calculated via means of equivalent circuit.MATLAB is used to calculate the relationship between the parameters of the ontology structure and the sound-absorption coefficient and the sound insulation.It is revealed that the sound barrier of the new ontology structure is 7.659.80 dB,which is more than the sound barrier of the traditional reflective structures.The relationships among the parameters of sound-absorption structure,sound-absorption coefficient,and sound insulation performance are obtained.In addition,the parameters can be transformed to satisfy the noise reduction requirements of various road sections,which has a admirable adaptability.The acoustic barrier can have tremendous acoustic performance only if there is a splendid sound insulation in the traffic noise frequency band.
基金National Natural Science Foundation of China(No.51705545)。
文摘The theory of active absorption of the perforated plate is proposed in this paper.The perforated plate is used as the material of active absorption and the depth of the cavity behind the perforated plate is changed according to the resonant frequency of the perforated plate.The rigid wall is moved to produce resonance so that the absorption coefficient can reach the maximal level.It is shown from the numerical calculation that when the perforated plate resonates,the moving distance is large at low frequencies,and the absorption coefficient is low under certain conditions.Perforated plate resonance is effective for single frequency of incident sound wave,which is difficult for the wide frequency,so active absorption based on airflow is posed,and the numerical calculation and experiment are carried out.The results denote that this method of active absorption is practical.
基金National Natural Science Foundation of China(Nos.51705545 and 15A460041)。
文摘The multilayer impedance composite sound absorption structure of the new muffler is proposed by combining the microporous plate structure with the resonant sound absorption structure of the porous material.Firstly,the acoustic impedance and acoustic absorption coefficient of the new muffler structure are calculated by acoustic electric analogy method,and then the noise attenuation is calculated.When the new muffler structure parameters change,the relationship among the noise frequency,the sound absorption coefficient and the noise attenuation is calculated by using MATLAB.Finally,the calculated results are compared with the experimental data to verify the correctness of the theoretical calculation.The variation of resonance peak,resonance frequency and attenuation band width of each structural parameter is analyzed by the relation curve.The conclusion shows that it is feasible to use multilayer sound absorbing materials as the body structure of the new muffler.And the influence relationship between the change of various parameters of the sound absorption structure with the sound absorption coefficient and noise attenuation is obtained.
基金Project(51705164)supported by the National Natural Science Foundation of China。
文摘The high-pressure electro-pneumatic servo valve(HESV)is a core element of the high-pressure pneumatic servo system.The annular clearance and the rounded corner of the spool-sleeve can cause the leakage at null position,thereby affecting high-precision control and stability of the servo system.This paper investigates the effects of the clearance structure on leakage behavior at null position of the HESV.A numerical approach was employed to evaluate the effects,and then a mathematical model was established to obtain the variation law of leakage flow rate at null position.The results indicate that the leakage flow rate at null position varies linearly with supply pressure and rounded corner radius,and is nonlinear as a quadratic concave function with annular clearance.The leakage flow rate of the annular clearance and the rounded corner varies with the valve opening in an invariable−nonlinear−linear trend.A test rig system of leakage behavior at null position of the HESV was built to confirm the validity of the numerical model,which agrees well with the conducted experimental study.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51575235)
文摘A tolerance modeling method of geometric variations within three-dimensional(3D) tolerance domain is proposed.According to the classification method of feature variations and classes of invariance or symmetry in the new generation Geometrical Product Specifications(GPS) system,the proposed method is based on the Small Displacement Torsor(SDT) concept,and SDT is used to represent the geometric deviations between the nominal feature and the fitting feature. Furthermore,the variation zones of several kinds complex or irregular geometric features are constructed,and the corresponding tolerance modeling methods are discussed respectively. Finally,an example is presented to verify the efficiency of the presented method for modeling 3D dimensional and geometrical tolerances.The proposed modeling method based on the complete mathematical foundation conforms with the design philosophy and principle of the new generation GPS standards system.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51175195,15A460041)
文摘The sound characteristic of the piezoelectric ceramics is posed for the excellent mechanic and electric coupling performance of piezoelectric material.Two pieces of piezoelectric ceramic are used as materials of active absorption and active isolation,two pieces of PVDF with equal distance are placed in the front of the material in order to measure the incidence plane wave and the reflected wave,the voltages are applied on the surface of the material in order to make the reflected wave and transmission wave be zero using the adaptive controlling.At last,emulation is carried out with plane wave,and good absorption and isolation effect is achieved.
文摘In the field of engineering,LabVIEW and MATLAB are the languages most commonly used by program developers.Howev-er,they have their respective advantages and disadvantages.The combination of the two will undoubtedly facilitate program develop-ment.Design of inference engine is the key point and difficulty in the design of fault diagnosis expert system.This paper combinesLabVIEW and MATLAB to design the inference engine of fault diagnosis expert system based on the advantages of the graphical pro-gramming environment and signal analysis toolkit of LabVIEW without the defect of neural network toolkit.In addition,it introducesthe implementation methods and precautions for combination of LabVIEW and BP network so as to make LabVIWE amd BP benefitfrom each other,which is of great pragmatic value.
基金supported by the National Natural Science Foundation of China(No.52188102).
文摘Anomaly Detection (AD) has been extensively adopted in industrial settings to facilitate quality control of products. It is critical to industrial production, especially to areas such as aircraft manufacturing, which require strict part qualification rates. Although being more efficient and practical, few-shot AD has not been well explored. The existing AD methods only extract features in a single frequency while defects exist in multiple frequency domains. Moreover, current methods have not fully leveraged the few-shot support samples to extract input-related normal patterns. To address these issues, we propose an industrial few-shot AD method, Feature Extender for Anomaly Detection (FEAD), which extracts normal patterns in multiple frequency domains from few-shot samples under the guidance of the input sample. Firstly, to achieve better coverage of normal patterns in the input sample, we introduce a Sample-Conditioned Transformation Module (SCTM), which transforms support features under the guidance of the input sample to obtain extra normal patterns. Secondly, to effectively distinguish and localize anomaly patterns in multiple frequency domains, we devise an Adaptive Descriptor Construction Module (ADCM) to build and select pattern descriptors in a series of frequencies adaptively. Finally, an auxiliary task for SCTM is designed to ensure the diversity of transformations and include more normal patterns into support features. Extensive experiments on two widely used industrial AD datasets (MVTec-AD and VisA) demonstrate the effectiveness of the proposed FEAD.
基金supported in part by National Key R&D Program of China(No.2021ZD0111501)National Natural Science Foundation of China(No.62176147)+2 种基金Science and Technology Planning Project of Guangdong Province of China(Nos.2021A0505030072 and 2022A1515110660)Science and Technology Special Funds Project of Guangdong Province of China(Nos.STKJ2021176 and STKJ2021019)STU Scientific Research Foundation for Talents(Nos.NTF21001 and NTF22030).
文摘Design automation is a core technology in industrial design software and an important branch of knowledge-worker automation.For example,electronic design automation(EDA)has played an important role in both academia and industry.Design automation for intelligent robots refers to the construction of unified modular graph models for the morphologies(body),controllers(brain),and vision systems(eye)of intelligent robots under digital twin architectures,which effectively supports the automation of the morphology,controller,and vision system design processes of intelligent robots by taking advantage of the powerful capabilities of genetic programming,evolutionary computation,deep learning,reinforcement learning,and causal reasoning in model representation,optimization,perception,decision making,and reasoning.Compared with traditional design methods,MOdular DEsigN Automation(MODENA)methods can significantly improve the design efficiency and performance of robots,effectively avoiding the repetitive trial-and-error processes of traditional design methods,and promoting automatic discovery of innovative designs.Thus,it is of considerable research significance to study MODENA methods for intelligent robots.To this end,this paper provides a systematic and comprehensive overview of applying MODENA in intelligent robots,analyzes the current problems and challenges in thefield,and provides an outlook for future research.First,the design automation for the robot morphologies and controllers is reviewed,individually,with automated design of control strategies for swarm robots also discussed,which has emerged as a prominent research focus recently.Next,the integrated design automation of both the morphologies and controllers for robotic systems is presented.Then,the design automation of the vision systems of intelligent robots is summarized when vision systems have become one of the most important modules for intelligent robotic systems.Then,the future research trends of integrated“Body-Brain-Eye”design automation for intelligent robots are discussed.Finally,the common key technologies,research challenges and opportunities in MODENA for intelligent robots are summarized.
基金financially supported by Beijing Advanced Innovation Center for Integrated Circuitsthe National Engineering Research Center for Offshore Windpower(HSFD22009).
文摘In this paper,an angular position sensor(APS)designed for a resonant miniaturized scanning mirror(M-SM)is presented.The APS operates based on the principle of differential variable capacitance,significantly expanding the detectable bandwidth from a few hertz to several kilohertz.By modeling the motion characteristics,the sampling rates of the biaxial scanning angles are 1473.6 times and 539.4 times higher than those of conventional sensors.Initially,the motion characteristics model is presented as a simple harmonic motion,converting sampled capacitance into continuous capacitance.Subsequently,the nonparallel state of the M-SM and sensor is transformed into a parallel state through the space coordinate system transformation.Furthermore,a 2D nonlinear angle transfer function is developed to convert the differential capacitance into an angle,thereby mitigating the nonlinear errors resulting from large angles.Achieving an accuracy better than 0.014°,the measuring range expands from±0.5729°(±10 mrad)to±5.026°(±87 mrad).Additionally,the capturing mode and tracking mode are proposed to monitor real-time angular changes of the M-SM with an accuracy of 0.017°.High-precision APSs have enhanced beam pointing accuracy and resolution and can thereby be used to advance the development of laser components,including light detection and ranging(LiDAR).
