Xiaojuan Sun, Shijie Liu, Hongliang Sun, Xingren Li, Yu Wang
Wheelset structural flexibility, that is the elastic deformation of the wheelset as a structure, has an important influence on the dynamic properties of railway locomotive vehicles at medium and high frequencies. Based on the practical structural parameters, this paper proposes a multi-degree of freedom rigid-flexible coupling dynamic model of a wide-gauge freight electric locomotive with C0-C0 bogies with an axle suspension driving system. The wheelset with the interference-fit large gear is made flexible using the finite element method, and then the rigid-flexible coupling vehicle model with elastic wheelsets is established in the software SIMPACK 2020. A short-wave irregularity superposed on the American fifth-grade track irregularity is used as the track excitation to study the performance at higher frequencies. From the modal analysis of the vehicle, it is obtained that the lowest frequency at which the elastic deformation of the wheelset occurs is 24.631 Hz. The lateral vibration responses of the vehicle with elastic wheelsets are reduced mainly in the frequency range of 30-150 Hz. There are two resonances in the lateral vibration responses at the mode frequencies of the vehicle over 50 Hz, which are close to the wheelset’s first mode frequency. Taking the ГОСТ standard of wide-gauge countries as the main reference, simulations are separately taken in straight-line and curved-line cases. Results show that the wheelset structural flexibility mainly influences the vehicle lateral stability and safety.
{"title":"Influence of wheelset structural flexibility on dynamic properties of a wide-gauge six-axle heavy-haul locomotive","authors":"Xiaojuan Sun, Shijie Liu, Hongliang Sun, Xingren Li, Yu Wang","doi":"10.21595/jve.2023.23353","DOIUrl":"https://doi.org/10.21595/jve.2023.23353","url":null,"abstract":"Wheelset structural flexibility, that is the elastic deformation of the wheelset as a structure, has an important influence on the dynamic properties of railway locomotive vehicles at medium and high frequencies. Based on the practical structural parameters, this paper proposes a multi-degree of freedom rigid-flexible coupling dynamic model of a wide-gauge freight electric locomotive with C0-C0 bogies with an axle suspension driving system. The wheelset with the interference-fit large gear is made flexible using the finite element method, and then the rigid-flexible coupling vehicle model with elastic wheelsets is established in the software SIMPACK 2020. A short-wave irregularity superposed on the American fifth-grade track irregularity is used as the track excitation to study the performance at higher frequencies. From the modal analysis of the vehicle, it is obtained that the lowest frequency at which the elastic deformation of the wheelset occurs is 24.631 Hz. The lateral vibration responses of the vehicle with elastic wheelsets are reduced mainly in the frequency range of 30-150 Hz. There are two resonances in the lateral vibration responses at the mode frequencies of the vehicle over 50 Hz, which are close to the wheelset’s first mode frequency. Taking the ГОСТ standard of wide-gauge countries as the main reference, simulations are separately taken in straight-line and curved-line cases. Results show that the wheelset structural flexibility mainly influences the vehicle lateral stability and safety.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44863800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wei Yan, Shouping Zhong, Huazhong Li, Jun Chen, Jian-jun Yang
Unstable vibrations in rotating machinery can stem from various causes, making it challenging to determine their origins. This research introduces the operational transfer path analysis method (OTPA) as a means to identify the causes of turbo generator vibrations. The model takes operational parameters, such as power and current, as input, and the vibration amplitude as output, to establish the source analysis model. To address the ill-conditioned input matrix, the singular value decomposition method is employed. By solving the transmissibility matrix and analyzing parameter contributions, the primary factors influencing vibration are identified. This method is applied to analyze the vibration sources in a 660 MW turbine generator unit. The generator experienced unstable vibration of unknown origin for a certain period. Operational transfer path analysis revealed that hydrogen pressure, hydrogen temperature, and bearing temperature significantly impacted the vibrations. Thermal imbalances and shaft misalignment in the generator rotor were inferred as the likely causes. Through adjustments to hydrogen pressure and temperature, the generator vibration was controlled until the next overhaul. Subsequent maintenance revealed partial blockage of the hydrogen ventilation holes, leading to rotor thermal imbalances. The feasibility of this method was confirmed. The objective of this study is to present an effective data-driven model for identifying the main influential parameters among numerous variables. This model can be applied to intelligent fault diagnosis in power generation units.
{"title":"Turbo generator vibration source identification based on operational transfer path analysis technology","authors":"Wei Yan, Shouping Zhong, Huazhong Li, Jun Chen, Jian-jun Yang","doi":"10.21595/jve.2023.23265","DOIUrl":"https://doi.org/10.21595/jve.2023.23265","url":null,"abstract":"Unstable vibrations in rotating machinery can stem from various causes, making it challenging to determine their origins. This research introduces the operational transfer path analysis method (OTPA) as a means to identify the causes of turbo generator vibrations. The model takes operational parameters, such as power and current, as input, and the vibration amplitude as output, to establish the source analysis model. To address the ill-conditioned input matrix, the singular value decomposition method is employed. By solving the transmissibility matrix and analyzing parameter contributions, the primary factors influencing vibration are identified. This method is applied to analyze the vibration sources in a 660 MW turbine generator unit. The generator experienced unstable vibration of unknown origin for a certain period. Operational transfer path analysis revealed that hydrogen pressure, hydrogen temperature, and bearing temperature significantly impacted the vibrations. Thermal imbalances and shaft misalignment in the generator rotor were inferred as the likely causes. Through adjustments to hydrogen pressure and temperature, the generator vibration was controlled until the next overhaul. Subsequent maintenance revealed partial blockage of the hydrogen ventilation holes, leading to rotor thermal imbalances. The feasibility of this method was confirmed. The objective of this study is to present an effective data-driven model for identifying the main influential parameters among numerous variables. This model can be applied to intelligent fault diagnosis in power generation units.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44786791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to improve the operation stability of high-speed railway vehicles, an emergency braking control method for high-speed railway vehicles based on the identification of foreign matters on the track surface is proposed. The dynamic frame scanning method is used to build the image acquisition of abnormal objects on the high-speed rail track surface, and the visual sensor and vibration sensor are used to identify and process the features of foreign objects on the high-speed rail track surface. According to the abnormal feature extraction results, the command signal in case of foreign objects is transmitted to the terminal command library of the braking control system. According to the transfer switch of the emergency braking system to display the main emergency disposal output states such as the train emergency disposal information reception, emergency disposal level, emergency disposal type and other information, the joint control method of contact pressure distribution and non-uniform heat flux is adopted, and the joint control method of control system, drive system, disc friction system and signal acquisition system is adopted. The emergency braking control module is established to realize the emergency braking control of high-speed railway vehicles according to the feature recognition results of foreign matters on the rail surface. The test results show that the control module is less affected by the vehicle wheelbase characteristics, track structure characteristics and other factors when using this method for high-speed railway vehicle emergency braking control, and has a strong ability to identify the characteristics of foreign matters on the track surface, which improves the stability and real-time performance of emergency braking.
{"title":"Research on high-speed railway vehicle emergency braking control based on rail surface foreign matter identification","authors":"Weihua Wang, Yaodong Zheng, Yuanjing Chen","doi":"10.21595/jve.2023.23426","DOIUrl":"https://doi.org/10.21595/jve.2023.23426","url":null,"abstract":"In order to improve the operation stability of high-speed railway vehicles, an emergency braking control method for high-speed railway vehicles based on the identification of foreign matters on the track surface is proposed. The dynamic frame scanning method is used to build the image acquisition of abnormal objects on the high-speed rail track surface, and the visual sensor and vibration sensor are used to identify and process the features of foreign objects on the high-speed rail track surface. According to the abnormal feature extraction results, the command signal in case of foreign objects is transmitted to the terminal command library of the braking control system. According to the transfer switch of the emergency braking system to display the main emergency disposal output states such as the train emergency disposal information reception, emergency disposal level, emergency disposal type and other information, the joint control method of contact pressure distribution and non-uniform heat flux is adopted, and the joint control method of control system, drive system, disc friction system and signal acquisition system is adopted. The emergency braking control module is established to realize the emergency braking control of high-speed railway vehicles according to the feature recognition results of foreign matters on the rail surface. The test results show that the control module is less affected by the vehicle wheelbase characteristics, track structure characteristics and other factors when using this method for high-speed railway vehicle emergency braking control, and has a strong ability to identify the characteristics of foreign matters on the track surface, which improves the stability and real-time performance of emergency braking.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45627203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Explosion shock wave pressure is one of the main damage parameters produced in the process of ammunition explosion, and it is also an important technical index to evaluate the damage power of ammunition. However, in the actual testing process, only a limited amount of shockwave pressure data at specific measuring points can be obtained, which cannot accurately reflect the distribution laws of the shockwave pressure propagation after the ammunition explosion. Therefore, it is particularly important to conduct reconstruction of the shockwave pressure field distribution laws based on limited measuring point data. This paper reviews the research work and related achievements obtained by researchers at home and abroad on the reconstruction of shockwave pressure distribution laws in explosion fields. The paper also elucidates the relevant application of computer tomography imaging techniques, shockwave propagation attenuation model reconstruction, and various interpolation algorithms in the reconstruction process of the shockwave pressure field. Given the current research situation both domestically and internationally, we have pinpointed the major issues that still exist in the current stage of research and proposed the key areas of focus that need attention in future research.
{"title":"Review of shock wave pressure reconstruction methods in explosion field","authors":"Liangquan Wang, D. Kong, F. Shang","doi":"10.21595/jve.2023.23310","DOIUrl":"https://doi.org/10.21595/jve.2023.23310","url":null,"abstract":"Explosion shock wave pressure is one of the main damage parameters produced in the process of ammunition explosion, and it is also an important technical index to evaluate the damage power of ammunition. However, in the actual testing process, only a limited amount of shockwave pressure data at specific measuring points can be obtained, which cannot accurately reflect the distribution laws of the shockwave pressure propagation after the ammunition explosion. Therefore, it is particularly important to conduct reconstruction of the shockwave pressure field distribution laws based on limited measuring point data. This paper reviews the research work and related achievements obtained by researchers at home and abroad on the reconstruction of shockwave pressure distribution laws in explosion fields. The paper also elucidates the relevant application of computer tomography imaging techniques, shockwave propagation attenuation model reconstruction, and various interpolation algorithms in the reconstruction process of the shockwave pressure field. Given the current research situation both domestically and internationally, we have pinpointed the major issues that still exist in the current stage of research and proposed the key areas of focus that need attention in future research.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48594220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tiancheng Tang, Bowen Wu, Wen Wang, Jiabao Pan, Yan Hu, Rui Xu, Dongdong Ye, Wei Yan
Short-pitch corrugation is a common phenomenon that occurs on tight-curve rails in metro systems. However, the contributing factors of this problem are still not fully understood, and effective control measures have yet to be developed. In this study, we investigated the contributing factors of short-pitch corrugation on tight-curve rails in metro systems using the complex eigenvalue analysis method according to the theory of friction-induced vibration. We also explored control measures for short-pitch corrugation from the perspective of optimizing the wheel web structure. Our results indicate that friction-induced vibration is the primary contributing factor to short-pitch corrugation in the wheel-rail system. The shape of the web structure significantly affects rail corrugation, and compared to the straight web structure, unstable vibrations are more pronounced in the S-shape web structure. In contrast, the bow web structure can significantly improve the system stability of the wheel-rail interaction, and the greater the web curvature, the better the inhibitory effect. The wheel deformation under contact force varies with the web curvature, and when the axial deformation of the wheel extends toward the inner rail, the wheel-rail system no longer exhibits unstable vibrations. Conversely, when the axial deformation of the wheel extends toward the outer rail, the greater the deformation, the greater the instability of the wheel-rail system.
{"title":"Influence of wheel web structure on the tight-curve short-pitch corrugation of metro","authors":"Tiancheng Tang, Bowen Wu, Wen Wang, Jiabao Pan, Yan Hu, Rui Xu, Dongdong Ye, Wei Yan","doi":"10.21595/jve.2023.23411","DOIUrl":"https://doi.org/10.21595/jve.2023.23411","url":null,"abstract":"Short-pitch corrugation is a common phenomenon that occurs on tight-curve rails in metro systems. However, the contributing factors of this problem are still not fully understood, and effective control measures have yet to be developed. In this study, we investigated the contributing factors of short-pitch corrugation on tight-curve rails in metro systems using the complex eigenvalue analysis method according to the theory of friction-induced vibration. We also explored control measures for short-pitch corrugation from the perspective of optimizing the wheel web structure. Our results indicate that friction-induced vibration is the primary contributing factor to short-pitch corrugation in the wheel-rail system. The shape of the web structure significantly affects rail corrugation, and compared to the straight web structure, unstable vibrations are more pronounced in the S-shape web structure. In contrast, the bow web structure can significantly improve the system stability of the wheel-rail interaction, and the greater the web curvature, the better the inhibitory effect. The wheel deformation under contact force varies with the web curvature, and when the axial deformation of the wheel extends toward the inner rail, the wheel-rail system no longer exhibits unstable vibrations. Conversely, when the axial deformation of the wheel extends toward the outer rail, the greater the deformation, the greater the instability of the wheel-rail system.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41431714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The thermal errors (TE) of computer numerical control (CNC) in workshop production seriously reduces the productivity. Therefore, to improve the productivity of CNC and enhance production intelligence, an improved adaptive TE compensation model (TECM) is proposed. The model is based on an online temperature measurement system (OTMS), which improves the adaptive learning rate of back-propagation neural network (BPNN) for temperature prediction. Finally, the correlation value between temperature changes and TEs is used for thermal error compensation. The performance verification of the model shows that the proposed OTMS can achieve effective temperature acquisition and processing, and the prediction ability of the improved BPNN is significantly higher than that of other prediction algorithms. Finally, it is found in the test that the improved adaptive TECM can reduce the contour error of workpiece machining to within 0.02×10-3 mm, the machining accuracy of CNC is significantly improved. The above results show that using the improved adaptive TECM can promote the intelligent development of CNC and improve their machining accuracy, which is of great significance to the development of workshop manufacturing.
{"title":"Intelligent CNC control with improved adaptive thermal error compensation model","authors":"Hui Shen, Liu Yang","doi":"10.21595/jve.2023.23205","DOIUrl":"https://doi.org/10.21595/jve.2023.23205","url":null,"abstract":"The thermal errors (TE) of computer numerical control (CNC) in workshop production seriously reduces the productivity. Therefore, to improve the productivity of CNC and enhance production intelligence, an improved adaptive TE compensation model (TECM) is proposed. The model is based on an online temperature measurement system (OTMS), which improves the adaptive learning rate of back-propagation neural network (BPNN) for temperature prediction. Finally, the correlation value between temperature changes and TEs is used for thermal error compensation. The performance verification of the model shows that the proposed OTMS can achieve effective temperature acquisition and processing, and the prediction ability of the improved BPNN is significantly higher than that of other prediction algorithms. Finally, it is found in the test that the improved adaptive TECM can reduce the contour error of workpiece machining to within 0.02×10-3 mm, the machining accuracy of CNC is significantly improved. The above results show that using the improved adaptive TECM can promote the intelligent development of CNC and improve their machining accuracy, which is of great significance to the development of workshop manufacturing.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45294292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Robotic arms are frequently utilized in contemporary industrial production since they offer great qualities like high precision and low mass. How to minimize robotic arm tremors in order to maximize their control effect has emerged as one of the most critical issues to be resolved with the continued development of industrial intelligence. The study uses a combination of PID control and an artificial fish swarm technique to optimize the parameters and confirm the simulation control effect based on the kinematic analysis of a six-degree-of-freedom (Six-DOF) modular robotic arm. The findings demonstrated that the suggested fusion approach converges to zero in 80 iterations and has a recall of 0.893 and 0.785 at an accuracy of 0.8 and 0.9, respectively. The robotic arm control system’s average control effect is 42.96 %, which is a respectable control performance. In the second and third studies, the fusion approach stabilized actuator end tremor suppression after 0.01 s and 0.0001 s, respectively. It shows that the technique can effectively suppress robotic arm bearing tremor and has high flexibility for robotic arm tremor suppression, which offers trustworthy technological support for improving the motion control system of industrial robots.
{"title":"Six-DOF modular robotic arm bearing chatter suppression algorithm","authors":"Man Zheng, Jun Jin","doi":"10.21595/jve.2023.23313","DOIUrl":"https://doi.org/10.21595/jve.2023.23313","url":null,"abstract":"Robotic arms are frequently utilized in contemporary industrial production since they offer great qualities like high precision and low mass. How to minimize robotic arm tremors in order to maximize their control effect has emerged as one of the most critical issues to be resolved with the continued development of industrial intelligence. The study uses a combination of PID control and an artificial fish swarm technique to optimize the parameters and confirm the simulation control effect based on the kinematic analysis of a six-degree-of-freedom (Six-DOF) modular robotic arm. The findings demonstrated that the suggested fusion approach converges to zero in 80 iterations and has a recall of 0.893 and 0.785 at an accuracy of 0.8 and 0.9, respectively. The robotic arm control system’s average control effect is 42.96 %, which is a respectable control performance. In the second and third studies, the fusion approach stabilized actuator end tremor suppression after 0.01 s and 0.0001 s, respectively. It shows that the technique can effectively suppress robotic arm bearing tremor and has high flexibility for robotic arm tremor suppression, which offers trustworthy technological support for improving the motion control system of industrial robots.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42189646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When the current transfer learning algorithm is applied to the field of bearing fault diagnosis under different working conditions, it only focuses on reducing the cross-domain distance or the distribution difference within the domain, and does not consider the domain tilt. When the fault samples are scarce, the degradation of recognition ability is more obvious. A fault diagnosis method for rolling bearings based on cross-domain divergence alignment and intra-domain distribution alienation (CDDA-IDDA) is proposed. Firstly, aiming at the cross-domain tilt in the domain data space of variable working conditions, the overall divergence matrix of source domain and target domain is constructed, and the cross-domain divergence alignment is carried out. Then, aiming at the overlapping phenomenon of categories in the domain, based on the distribution adaptation weighted conditional distribution, the spatial distribution of different categories in the same domain is further alienated. Finally, the regularization term is introduced under the framework of structural risk minimization. On the basis of fully retaining the internal structure of the data, a multi-classifier with strong transfer ability is obtained by iteration. Experiments show that the proposed method is better than some mainstream transfer learning algorithms in multi-fault, multi-degree recognition and compound fault diagnosis. In addition, the proposed method still has high diagnostic accuracy when there are few labeled training samples. When the ratio of labeled source domain samples to unlabeled target domain is 1:50 (16 labeled data), the average accuracy of the transfer task reaches 97.78 %.
{"title":"Fault diagnosis of rolling bearing based on cross-domain divergence alignment and intra-domain distribution alienation","authors":"Shubiao Zhao, Guangbin Wang, Xuejun Li, Jinhua Chen, Lingli Jiang","doi":"10.21595/jve.2023.23210","DOIUrl":"https://doi.org/10.21595/jve.2023.23210","url":null,"abstract":"When the current transfer learning algorithm is applied to the field of bearing fault diagnosis under different working conditions, it only focuses on reducing the cross-domain distance or the distribution difference within the domain, and does not consider the domain tilt. When the fault samples are scarce, the degradation of recognition ability is more obvious. A fault diagnosis method for rolling bearings based on cross-domain divergence alignment and intra-domain distribution alienation (CDDA-IDDA) is proposed. Firstly, aiming at the cross-domain tilt in the domain data space of variable working conditions, the overall divergence matrix of source domain and target domain is constructed, and the cross-domain divergence alignment is carried out. Then, aiming at the overlapping phenomenon of categories in the domain, based on the distribution adaptation weighted conditional distribution, the spatial distribution of different categories in the same domain is further alienated. Finally, the regularization term is introduced under the framework of structural risk minimization. On the basis of fully retaining the internal structure of the data, a multi-classifier with strong transfer ability is obtained by iteration. Experiments show that the proposed method is better than some mainstream transfer learning algorithms in multi-fault, multi-degree recognition and compound fault diagnosis. In addition, the proposed method still has high diagnostic accuracy when there are few labeled training samples. When the ratio of labeled source domain samples to unlabeled target domain is 1:50 (16 labeled data), the average accuracy of the transfer task reaches 97.78 %.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136020767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qirui Liu, Changliang Tang, Ting-Ying Wu, Yujie Bai
The pivot-jewel bearing pair is the only dynamic and static contact component of the flexible vertical rotor system, and its support stiffness directly affects the dynamic response of the rotor system. A non-linear dynamic model of the vertical rotor system is established, and the effect of different elastic pivot stiffnesses on the dynamic behavior of the rotor system is investigated in combination with experiments. The results show that with the increase of rotational speed, the system has the dynamic characteristics of alternating period 1 and quasi period, and when the speed reaches 550 r/s, 1/3 times low frequency whirl occurs and when the speed rises to 675 r/s, the low frequency amplitude is higher than the rotational frequency amplitude. With the increase of the elastic pivot stiffness, the amplitude of the low frequency whirl at the lower end of the rotor decreases continuously but the proportion of the “width” gradually increases. The rotational speed corresponding to the large amplitude quasi periodic motion of the rotor is delayed from 550 r/s to 650 r/s. The research results can provide a theoretical basis for the optimal design of the bearing subsystem of the vertical rotor system.
{"title":"Influence of pivot support stiffness on dynamic characteristics of vertical rotor system","authors":"Qirui Liu, Changliang Tang, Ting-Ying Wu, Yujie Bai","doi":"10.21595/jve.2023.23136","DOIUrl":"https://doi.org/10.21595/jve.2023.23136","url":null,"abstract":"The pivot-jewel bearing pair is the only dynamic and static contact component of the flexible vertical rotor system, and its support stiffness directly affects the dynamic response of the rotor system. A non-linear dynamic model of the vertical rotor system is established, and the effect of different elastic pivot stiffnesses on the dynamic behavior of the rotor system is investigated in combination with experiments. The results show that with the increase of rotational speed, the system has the dynamic characteristics of alternating period 1 and quasi period, and when the speed reaches 550 r/s, 1/3 times low frequency whirl occurs and when the speed rises to 675 r/s, the low frequency amplitude is higher than the rotational frequency amplitude. With the increase of the elastic pivot stiffness, the amplitude of the low frequency whirl at the lower end of the rotor decreases continuously but the proportion of the “width” gradually increases. The rotational speed corresponding to the large amplitude quasi periodic motion of the rotor is delayed from 550 r/s to 650 r/s. The research results can provide a theoretical basis for the optimal design of the bearing subsystem of the vertical rotor system.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48348956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As the industrial robot task becomes more complex, the difficulty of trajectory planning and tracking control of manipulator is gradually increasing. To minimize the vibration during the manipulator motion and improve the planning accuracy, the method of quintic polynomial combined with non-uniform B-spline interpolation is studied for joint space (JS) planning. The trajectory tracking system is easily affected by friction nonlinearity and parameters. So a JS trajectory tracking controller based on based on fuzzy neural network (FNN) is designed. Through simulation experiments, the curve obtained by the planning method studied is smoother and the planning error is minimum. The maximum position error is 0.09 rad, and the speed error is not more than 0.1 rad/s. The controller performance test results under different parameters show that the W^, c^, κ^ parameter in FNN can be adjusted in real time, and the value will not affect the performance of the controller. The fluctuation range of trajectory error of different joints is within ±0.2×10-5rad, which indicates that the performance of AFNNC controller studied is better. And its response time is the shortest and its robustness is better when the load changes suddenly.
{"title":"Trajectory planning and control algorithm of industrial robot manipulator","authors":"Jing Liu","doi":"10.21595/jve.2023.23274","DOIUrl":"https://doi.org/10.21595/jve.2023.23274","url":null,"abstract":"As the industrial robot task becomes more complex, the difficulty of trajectory planning and tracking control of manipulator is gradually increasing. To minimize the vibration during the manipulator motion and improve the planning accuracy, the method of quintic polynomial combined with non-uniform B-spline interpolation is studied for joint space (JS) planning. The trajectory tracking system is easily affected by friction nonlinearity and parameters. So a JS trajectory tracking controller based on based on fuzzy neural network (FNN) is designed. Through simulation experiments, the curve obtained by the planning method studied is smoother and the planning error is minimum. The maximum position error is 0.09 rad, and the speed error is not more than 0.1 rad/s. The controller performance test results under different parameters show that the W^, c^, κ^ parameter in FNN can be adjusted in real time, and the value will not affect the performance of the controller. The fluctuation range of trajectory error of different joints is within ±0.2×10-5rad, which indicates that the performance of AFNNC controller studied is better. And its response time is the shortest and its robustness is better when the load changes suddenly.","PeriodicalId":49956,"journal":{"name":"Journal of Vibroengineering","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48621150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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