Abstract: A fuzzy sliding mode variable structure control method based on road surface recognition was proposed to solve the problem that the Anti-lock Braking system (ABS) effect of current ABS algorithm was not ideal on complex road surface. In the road recognition module, real-time estimation of 5 typical road surfaces using fuzzy logic control. Dynamic calculation of optimal slip ratio for different road surfaces based on identified road conditions. Design of ABS sliding mode variable structure controller with optimal slip ratio and actual slip ratio as input. Aiming at the chattering problem of sliding mode control, a fuzzy controller is designed to reduce chattering. An 8-DOF dynamic simulation model of a four-wheel hub motor is established. The effectiveness of the controller is verified by braking simulation experiments on medium and low adhesion road. By comparing the simulation test with the traditional sliding mode controller under the condition of high adhesion road, the suppression effect of the system chattering is verified, and its excellent control performance is proved.
{"title":"Design of ABS fuzzy sliding mode control system based on pavement recognition","authors":"Shuaiwei Zhu, Xiao-bin Fan, Pan Wang, Xinbo Chen","doi":"10.1139/tcsme-2022-0098","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0098","url":null,"abstract":"Abstract: A fuzzy sliding mode variable structure control method based on road surface recognition was proposed to solve the problem that the Anti-lock Braking system (ABS) effect of current ABS algorithm was not ideal on complex road surface. In the road recognition module, real-time estimation of 5 typical road surfaces using fuzzy logic control. Dynamic calculation of optimal slip ratio for different road surfaces based on identified road conditions. Design of ABS sliding mode variable structure controller with optimal slip ratio and actual slip ratio as input. Aiming at the chattering problem of sliding mode control, a fuzzy controller is designed to reduce chattering. An 8-DOF dynamic simulation model of a four-wheel hub motor is established. The effectiveness of the controller is verified by braking simulation experiments on medium and low adhesion road. By comparing the simulation test with the traditional sliding mode controller under the condition of high adhesion road, the suppression effect of the system chattering is verified, and its excellent control performance is proved.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43867760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most servo systems in power line inspection robots consist of a motor, an independent joint, and a load. In the process of crossing obstacles, the parameters in the servo systems have conspicuous time-varying properties due to the posture changes. The time-varying properties of dynamic parameters and the flexibility of the load would cause the rotation speed of the inspection robot to fluctuate, thereby affecting the motion accuracy. In this paper, the pole placement strategy was proposed to optimize the parameters in the proportional integral (PI) controller. The optimal controller parameters were selected in different postures to ensure steady speed output in the inspection robot servo system. First, the dynamic equations of the inspection robot servo system were established. Both joint flexibility and load flexibility were considered in the modeling process. Then, the Arnoldi algorithm was used to reduce the order of the servo system, and the transfer function from the speed to the drive torque was obtained. Next, the controller parameters were optimized using the pole placement method. By reasonably selecting the pole damping coefficient, the inspection robot could obtain a stable speed output. Finally, the numerical analysis and speed control of the inspection robot in different postures were analyzed. The results showed that the control strategy of pole placement could achieve a stable rotation speed for the inspection robot.
{"title":"Speed control strategy for power line inspection robot servo system considering time-varying parameters","authors":"Dongyang Shang, Xiaopeng Li, Fanjie Li, Hexu Yang","doi":"10.1139/tcsme-2022-0123","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0123","url":null,"abstract":"Most servo systems in power line inspection robots consist of a motor, an independent joint, and a load. In the process of crossing obstacles, the parameters in the servo systems have conspicuous time-varying properties due to the posture changes. The time-varying properties of dynamic parameters and the flexibility of the load would cause the rotation speed of the inspection robot to fluctuate, thereby affecting the motion accuracy. In this paper, the pole placement strategy was proposed to optimize the parameters in the proportional integral (PI) controller. The optimal controller parameters were selected in different postures to ensure steady speed output in the inspection robot servo system. First, the dynamic equations of the inspection robot servo system were established. Both joint flexibility and load flexibility were considered in the modeling process. Then, the Arnoldi algorithm was used to reduce the order of the servo system, and the transfer function from the speed to the drive torque was obtained. Next, the controller parameters were optimized using the pole placement method. By reasonably selecting the pole damping coefficient, the inspection robot could obtain a stable speed output. Finally, the numerical analysis and speed control of the inspection robot in different postures were analyzed. The results showed that the control strategy of pole placement could achieve a stable rotation speed for the inspection robot.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44664670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a magnetic rheological (MR) semi-active control method based on Bidirectional Long Short-Term Memory (BiLSTM) neural network, linear quadratic regulator (LQR) control algorithm and genetic algorithm (GA). The LQR algorithm with GA optimizing the weight coefficients generates the expected damping force. Due to the nonlinear hysteresis characteristics of the MR damper (MRD) and the fact that its input and output have certain time dependence, an inverse model of MRD is established by BiLSTM. The control current is predicted by BiLSTM and then the current is input to the MR damper to obtain the damping force that is infinitely close to the expected damping force. The damping force is then applied to the suspension system to form a complete closed-loop feedback control, which realizes the damping effect and generates a real-time control. The simulation results show that the MRD inverse model can accurately predict the required control current, and the GA-optimized LQR control algorithm has a good suppression effect on the vertical vehicle acceleration (VVA), dynamic tire load (DTL) and suspension dynamic stroke (SDS).
{"title":"GA-LQR for vehicle semi-active suspension with BiLSTM inverse model of magnetic rheological damper","authors":"C. Chen, R. Ma, Wan Ma","doi":"10.1139/tcsme-2023-0027","DOIUrl":"https://doi.org/10.1139/tcsme-2023-0027","url":null,"abstract":"This paper proposes a magnetic rheological (MR) semi-active control method based on Bidirectional Long Short-Term Memory (BiLSTM) neural network, linear quadratic regulator (LQR) control algorithm and genetic algorithm (GA). The LQR algorithm with GA optimizing the weight coefficients generates the expected damping force. Due to the nonlinear hysteresis characteristics of the MR damper (MRD) and the fact that its input and output have certain time dependence, an inverse model of MRD is established by BiLSTM. The control current is predicted by BiLSTM and then the current is input to the MR damper to obtain the damping force that is infinitely close to the expected damping force. The damping force is then applied to the suspension system to form a complete closed-loop feedback control, which realizes the damping effect and generates a real-time control. The simulation results show that the MRD inverse model can accurately predict the required control current, and the GA-optimized LQR control algorithm has a good suppression effect on the vertical vehicle acceleration (VVA), dynamic tire load (DTL) and suspension dynamic stroke (SDS).","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42626023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a two-level stress correction method to overcome the limitations of the element stress average method that is typically used to calculate the nodal stress in finite element analyses and increase the fatigue life evaluation accuracy at the stiffness mutation positions of large-scale structure. In the first stage, a standard-deviation-weighted stress smoothing method is used to address the high element stress dispersion at the stiffness mutation point. The second stage involves a stress gradient correction method established based on the theory that the nodal stress is affected by other nodal stresses on the stress gradient path. The nodal stresses of the key points of an 80 tons gondola car body are extracted using the two-level stress correction method, and the fatigue life of the key points is evaluated considering the load spectrum of the Daqin coal line. The fatigue lives corresponding to the measured stress spectrum at the key points are compared with the simulated values. Compared with that obtained by the traditional method, the fatigue life of the key joints obtained by the proposed method is closer to the actual fatigue life. Additionally, the nodal stress at the stiffness mutation position obtained by the proposed method is more accurate. Therefore, the two-level stress correction method is a promising platform for the fatigue life evaluation of large-scale structures.
{"title":"Research and application of nodal stress correction at stiffness mutation position for fatigue life evaluation","authors":"Wenfei Liu, Ling Zhang, Liwen He, Zhixiong Gao","doi":"10.1139/tcsme-2022-0163","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0163","url":null,"abstract":"This paper proposes a two-level stress correction method to overcome the limitations of the element stress average method that is typically used to calculate the nodal stress in finite element analyses and increase the fatigue life evaluation accuracy at the stiffness mutation positions of large-scale structure. In the first stage, a standard-deviation-weighted stress smoothing method is used to address the high element stress dispersion at the stiffness mutation point. The second stage involves a stress gradient correction method established based on the theory that the nodal stress is affected by other nodal stresses on the stress gradient path. The nodal stresses of the key points of an 80 tons gondola car body are extracted using the two-level stress correction method, and the fatigue life of the key points is evaluated considering the load spectrum of the Daqin coal line. The fatigue lives corresponding to the measured stress spectrum at the key points are compared with the simulated values. Compared with that obtained by the traditional method, the fatigue life of the key joints obtained by the proposed method is closer to the actual fatigue life. Additionally, the nodal stress at the stiffness mutation position obtained by the proposed method is more accurate. Therefore, the two-level stress correction method is a promising platform for the fatigue life evaluation of large-scale structures.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46707371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Magnetorheological damper (MRD) is widely used in civil engineering, heavy-duty vehicles to speed up safely and so on. In this paper, a MR controller for adjusting the stiffness and damping of a semi-active air suspension is designed to improve the vibration resistance of the Electric Multiple Units (EMU) suspension system. The 3D magnetic field simulations of the MR controller are carried out. The influences of factors such as shaft material, damping channel width, cylinder wall thickness on the magnetic induction intensity at the damping channel are studied. An orthogonal experiment is carried out and the optimal combination of the structural parameters is determined. Then, the four working conditions of the MR controller are simulated and analyzed respectively, and its structure is improved to ensure its stability. Finally, using fluid simulation software analysis, it can be seen that due to the fluidity of magnetorheological fluids (MRFs), the heat generated by the coil has little effect on MRFs.
{"title":"Magnetic circuit design of MR controller for improving the performance of the suspension","authors":"C. Chen, R. Ma, Wan Ma","doi":"10.1139/tcsme-2023-0019","DOIUrl":"https://doi.org/10.1139/tcsme-2023-0019","url":null,"abstract":"Magnetorheological damper (MRD) is widely used in civil engineering, heavy-duty vehicles to speed up safely and so on. In this paper, a MR controller for adjusting the stiffness and damping of a semi-active air suspension is designed to improve the vibration resistance of the Electric Multiple Units (EMU) suspension system. The 3D magnetic field simulations of the MR controller are carried out. The influences of factors such as shaft material, damping channel width, cylinder wall thickness on the magnetic induction intensity at the damping channel are studied. An orthogonal experiment is carried out and the optimal combination of the structural parameters is determined. Then, the four working conditions of the MR controller are simulated and analyzed respectively, and its structure is improved to ensure its stability. Finally, using fluid simulation software analysis, it can be seen that due to the fluidity of magnetorheological fluids (MRFs), the heat generated by the coil has little effect on MRFs.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44741956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi Huang, Yong Hu, Jianwu Liu, S. M. Tarikul Islam
Aiming at the shortcomings of the traditional robot obstacle avoidance algorithm applied directly to the leader-follower task transformation of concrete pump truck boom, an algorithm combined with improved danger field and improved gradient projection method for obstacle avoidance control of the boom is proposed. In the method, a joint limit avoidance function is used to avoid the angle overrun of the boom joints. And the danger field expression is modified to improve its engineering suitability. Moreover, a smoothing adjustment factor is introduced to improve the smoothness of the leader-follower task transformation of the boom. The influence of key control parameters on the safety and accuracy of boom movement is discussed through the simulation, and the reasonable ranges of the parameters are given. Furthermore, experiments are carried out to verify the effectiveness of the algorithm. The method provides a solution for obstacle avoidance control of construction machinery with multi-joint series boom.
{"title":"Simulation and experiment on obstacle avoidance control of concrete pump truck boom based on improved danger field and gradient projection method","authors":"Yi Huang, Yong Hu, Jianwu Liu, S. M. Tarikul Islam","doi":"10.1139/tcsme-2022-0134","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0134","url":null,"abstract":"Aiming at the shortcomings of the traditional robot obstacle avoidance algorithm applied directly to the leader-follower task transformation of concrete pump truck boom, an algorithm combined with improved danger field and improved gradient projection method for obstacle avoidance control of the boom is proposed. In the method, a joint limit avoidance function is used to avoid the angle overrun of the boom joints. And the danger field expression is modified to improve its engineering suitability. Moreover, a smoothing adjustment factor is introduced to improve the smoothness of the leader-follower task transformation of the boom. The influence of key control parameters on the safety and accuracy of boom movement is discussed through the simulation, and the reasonable ranges of the parameters are given. Furthermore, experiments are carried out to verify the effectiveness of the algorithm. The method provides a solution for obstacle avoidance control of construction machinery with multi-joint series boom.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49236252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The 3d modification is a advanced technology that comprehensively considers tooth profile modification and axial modification to reduce vibration and noise. Therefore, this paper combines 3d modification technology with contact characteristics and dynamic properties to study the influence of 3d modification on the dynamic performance of herringbone gear system. This paper employs parabolic tooth profile instead of the cutter straight tooth profile to achieve 3d modified tooth surface and deduces tooth surface equation. Then, the tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA) are used to simulate the meshing process of teeth. And the dynamic model of herringbone gear system under three internal excitations is established. Finally, 3d modification, TCA, LTCA technology and gear dynamic characteristics are combined to study the influence of 3d modification on the system dynamic behavior. The results show that, compared with tooth profile modification and axial modification, the 3d modification can effectively compensate the influence of errors on gear system and have very good damping effect. The relative vibration displacements on the left and right meshing lines of gear pair are reduced by 47.60% and 51.20%, and root mean square values are decreased by 30.50% and 36.10% before and after modification.
{"title":"Study on the influence of 3d modification on dynamic characteristics of herringbone gear transmission system","authors":"Zhibin Li, S. Wang","doi":"10.1139/tcsme-2022-0148","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0148","url":null,"abstract":"The 3d modification is a advanced technology that comprehensively considers tooth profile modification and axial modification to reduce vibration and noise. Therefore, this paper combines 3d modification technology with contact characteristics and dynamic properties to study the influence of 3d modification on the dynamic performance of herringbone gear system. This paper employs parabolic tooth profile instead of the cutter straight tooth profile to achieve 3d modified tooth surface and deduces tooth surface equation. Then, the tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA) are used to simulate the meshing process of teeth. And the dynamic model of herringbone gear system under three internal excitations is established. Finally, 3d modification, TCA, LTCA technology and gear dynamic characteristics are combined to study the influence of 3d modification on the system dynamic behavior. The results show that, compared with tooth profile modification and axial modification, the 3d modification can effectively compensate the influence of errors on gear system and have very good damping effect. The relative vibration displacements on the left and right meshing lines of gear pair are reduced by 47.60% and 51.20%, and root mean square values are decreased by 30.50% and 36.10% before and after modification.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45072557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper compares the combustion behavior and emission of a turbocharged compression ignition engine fueled with biodiesel BD100, dimethyl ether DME100, low-proportioned biodiesel blends BD30, and medium-proportioned biodiesel blends BD50. The impacts of biodiesel ratio and nozzle diameter on combustion and emissions characteristics were determined. The findings show that BD100 with a nozzle 6 × 0.24 mm has the highest value of maximum pressure, maximum pressure rise rate, maximum heat release rate, and NOx emissions. DME100 with a nozzle of 6 × 0.40 mm has the lowest values. CO emissions and HC emissions of BD100 with a nozzle 6 × 0.24 mm and DME100 with nozzles 6 × 0.40 mm and 6 × 0.35 mm gradually decrease. Among biodiesel blends, BD30 and BD50 with two types of nozzles, BD30 with a nozzle 6 × 0.40 mm has the lowest value of maximum pressure, maximum pressure rise rate, NOx emissions, and soot emissions. Compared with BD50, BD30 with nozzles 6 × 0.35 mm and 6 × 0.40 mm has lower CO emissions, HC emissions, and smoke emissions.
{"title":"Effects of biodiesel ratio and nozzle diameter on combustion and emissions of a biodiesel–DME-fueled engine","authors":"J. Hou, Shuanghui Xi, Zhenghe Wang, Shuhao Li","doi":"10.1139/tcsme-2022-0130","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0130","url":null,"abstract":"This paper compares the combustion behavior and emission of a turbocharged compression ignition engine fueled with biodiesel BD100, dimethyl ether DME100, low-proportioned biodiesel blends BD30, and medium-proportioned biodiesel blends BD50. The impacts of biodiesel ratio and nozzle diameter on combustion and emissions characteristics were determined. The findings show that BD100 with a nozzle 6 × 0.24 mm has the highest value of maximum pressure, maximum pressure rise rate, maximum heat release rate, and NOx emissions. DME100 with a nozzle of 6 × 0.40 mm has the lowest values. CO emissions and HC emissions of BD100 with a nozzle 6 × 0.24 mm and DME100 with nozzles 6 × 0.40 mm and 6 × 0.35 mm gradually decrease. Among biodiesel blends, BD30 and BD50 with two types of nozzles, BD30 with a nozzle 6 × 0.40 mm has the lowest value of maximum pressure, maximum pressure rise rate, NOx emissions, and soot emissions. Compared with BD50, BD30 with nozzles 6 × 0.35 mm and 6 × 0.40 mm has lower CO emissions, HC emissions, and smoke emissions.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44757768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fault diagnosis is an important method for maintaining the stable and safe running state of mechanical equipment. As most mechanical equipment faults are induced by the bearing assembly, bearing fault diagnosis is of considerable importance. At present, the mainstream intelligent diagnostic techniques include supervised learning and unsupervised learning. Supervised learning requires manual labeling and data classification, which is unfavorable for massive data amounts. Therefore, how to effectively use labeled data to increase the accuracy of diagnosis is critical, especially when the bearing failure cannot be labeled at the very beginning. This paper proposes a time–frequency analysis of the short-time Fourier transform and wavelet transform methods based on unsupervised learning. The time axis was integrated to obtain the marginal frequency of two frequency domains as a diagnostic feature, and then two clustering centroids were established automatically by the K-means of unsupervised learning. The signals were divided into two classes based on the nearest clustering centroid as the criteria for diagnosis. Finally, other bearings in different positions were classified and diagnosed using the nearest clustering centroid in the same experiment to verify the effectiveness of the method proposed in this study.
{"title":"A novel rolling bearing fault diagnosis method based on marginal spectrum","authors":"Kuohao Li, Yaochi Tang","doi":"10.1139/tcsme-2022-0121","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0121","url":null,"abstract":"Fault diagnosis is an important method for maintaining the stable and safe running state of mechanical equipment. As most mechanical equipment faults are induced by the bearing assembly, bearing fault diagnosis is of considerable importance. At present, the mainstream intelligent diagnostic techniques include supervised learning and unsupervised learning. Supervised learning requires manual labeling and data classification, which is unfavorable for massive data amounts. Therefore, how to effectively use labeled data to increase the accuracy of diagnosis is critical, especially when the bearing failure cannot be labeled at the very beginning. This paper proposes a time–frequency analysis of the short-time Fourier transform and wavelet transform methods based on unsupervised learning. The time axis was integrated to obtain the marginal frequency of two frequency domains as a diagnostic feature, and then two clustering centroids were established automatically by the K-means of unsupervised learning. The signals were divided into two classes based on the nearest clustering centroid as the criteria for diagnosis. Finally, other bearings in different positions were classified and diagnosed using the nearest clustering centroid in the same experiment to verify the effectiveness of the method proposed in this study.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47639140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study is motivated by condition monitoring and fault diagnostic of structural beams used in large-scale vibrating screens for mining industry. For the purpose of developing a reliable model-based approach, a new stiffness matrix of a 3-dimensional finite element is proposed for modelling a beam with a breathing crack. Using the obtained stiffness matrix, a finite element model is derived for a cracked beam subjected to a bi-directional base excitation. With the model, a computer simulation is conducted to examine the influences of the crack depth on the natural frequencies of the beam. The numerical results show that the crack influences mainly the natural frequencies of the bending modes in the direction of the crack grow. The simulation also investigates the responses of the beam subjected to a harmonic base excitation in two directions. The numerical results show that the responses of the cracked beam contain several super-harmonic components, and the amplitude of super-harmonic components increases with the increase of crack depth. Experiments are conducted to validate the proposed dynamic model using both impact testing and forced testing.
{"title":"Vibration Analysis of a Cracked Beam Using the Finite Element Method","authors":"Hui Long, Yilun Liu, Kefu Liu","doi":"10.1139/tcsme-2022-0155","DOIUrl":"https://doi.org/10.1139/tcsme-2022-0155","url":null,"abstract":"This study is motivated by condition monitoring and fault diagnostic of structural beams used in large-scale vibrating screens for mining industry. For the purpose of developing a reliable model-based approach, a new stiffness matrix of a 3-dimensional finite element is proposed for modelling a beam with a breathing crack. Using the obtained stiffness matrix, a finite element model is derived for a cracked beam subjected to a bi-directional base excitation. With the model, a computer simulation is conducted to examine the influences of the crack depth on the natural frequencies of the beam. The numerical results show that the crack influences mainly the natural frequencies of the bending modes in the direction of the crack grow. The simulation also investigates the responses of the beam subjected to a harmonic base excitation in two directions. The numerical results show that the responses of the cracked beam contain several super-harmonic components, and the amplitude of super-harmonic components increases with the increase of crack depth. Experiments are conducted to validate the proposed dynamic model using both impact testing and forced testing.","PeriodicalId":23285,"journal":{"name":"Transactions of The Canadian Society for Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44922547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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