Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110011
Yuren Li, Hongyu Zhang, Liang Tian, Yufan Zhang, Y. Rao, Yuntong Li, Bo Liang
The anti-skid braking system of unmanned aerial vehicle has the characteristics of high-order nonlinearity, strong coupling, and time-varying parameters, which will seriously affect the taxiing performance of the unmanned aerial vehicle. This paper proposed a cascaded fast terminal sliding mode control method for unmanned aerial vehicle electric braking system, which can accurately track the optimal slip rate and ensure the stability of the braking system. First, the electric braking system model of unmanned aerial vehicle is established, which gets rid of the reliance on the ground binding coefficient fitting formulas. Second, combined with the concept of the inversion control, the cascaded fast terminal sliding mode controller is designed to achieve the accurate tracking of the slip rate and the reference braking force. The stability of the controller is proved by the Lyapunov stability theory. Finally, the effectiveness of the proposed control strategy is verified by simulation results.
{"title":"Cascaded fast terminal sliding mode control for UAV electric braking system","authors":"Yuren Li, Hongyu Zhang, Liang Tian, Yufan Zhang, Y. Rao, Yuntong Li, Bo Liang","doi":"10.1051/jnwpu/20234110011","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110011","url":null,"abstract":"The anti-skid braking system of unmanned aerial vehicle has the characteristics of high-order nonlinearity, strong coupling, and time-varying parameters, which will seriously affect the taxiing performance of the unmanned aerial vehicle. This paper proposed a cascaded fast terminal sliding mode control method for unmanned aerial vehicle electric braking system, which can accurately track the optimal slip rate and ensure the stability of the braking system. First, the electric braking system model of unmanned aerial vehicle is established, which gets rid of the reliance on the ground binding coefficient fitting formulas. Second, combined with the concept of the inversion control, the cascaded fast terminal sliding mode controller is designed to achieve the accurate tracking of the slip rate and the reference braking force. The stability of the controller is proved by the Lyapunov stability theory. Finally, the effectiveness of the proposed control strategy is verified by simulation results.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44160806","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110001
Jiyu Xia, Zhou Zhou, Zhengping Wang, Rui Wang
Aiming at the vertical take-off and landing mode of tilt-propulsion UAV with uncertainties such as external environment disturbance and internal parameter perturbation, this paper studies the trajectory tracking control, and proposes an internal and external double loop sliding mode control scheme based on nonlinear extended state observer (NLESO). Firstly, according to the characteristics of tilt-propulsion UAV, the dynamic model of propulsion system, aerodynamic model of fuselage/wing and yaw rudder, and dynamic equation are established in turn to complete the dynamic modeling work. Then, the internal and external uncertainties are regarded as lumped disturbances, and NLESO is designed to estimate them and compensate the control system. Afterwards, based on NLESO and sliding mode control method, the position and attitude double loop controller of VTOL mode is designed. Finally, the Lyapunov function is designed to analyze the stability of NLESO and the whole control system. Simulation results show that the proposed method significantly improves the trajectory tracking response speed and the ability to suppress uncertainties of vertical take-off and landing mode of tilt dynamic UAV.
{"title":"Trajectory tracking control of tilt-propulsion UAV vertical take-off and landing mode based on NLESO","authors":"Jiyu Xia, Zhou Zhou, Zhengping Wang, Rui Wang","doi":"10.1051/jnwpu/20234110001","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110001","url":null,"abstract":"Aiming at the vertical take-off and landing mode of tilt-propulsion UAV with uncertainties such as external environment disturbance and internal parameter perturbation, this paper studies the trajectory tracking control, and proposes an internal and external double loop sliding mode control scheme based on nonlinear extended state observer (NLESO). Firstly, according to the characteristics of tilt-propulsion UAV, the dynamic model of propulsion system, aerodynamic model of fuselage/wing and yaw rudder, and dynamic equation are established in turn to complete the dynamic modeling work. Then, the internal and external uncertainties are regarded as lumped disturbances, and NLESO is designed to estimate them and compensate the control system. Afterwards, based on NLESO and sliding mode control method, the position and attitude double loop controller of VTOL mode is designed. Finally, the Lyapunov function is designed to analyze the stability of NLESO and the whole control system. Simulation results show that the proposed method significantly improves the trajectory tracking response speed and the ability to suppress uncertainties of vertical take-off and landing mode of tilt dynamic UAV.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48844029","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110209
Jinghui Deng, Zhi-Peng Yu, Yun-Feng Zhou, Bin Song
A rotor dynamic analysis method for the complex three-dimensional design blade was developed and applied to analyzing its aeroelastic stability. Based on the medium-size deformation beam theory and Hamilton principle, the joint transfer matrix was used in the blade kinematic and the deformation compatibility principle was used in the assembled finite element matrix to develop the complex three-dimensional rotor structural dynamics model. The BO105 rotor was used to validate this method and the aeroelastic characteristic of the complex three-dimensional rotor was analyzed in detail. The results showed that the negative structural coupling of flap-torsion was appeared with tip sweep, and the 1/rev torsion modal frequency was decreased, and the 1/rev torsion modal damping ratio was maximally decreased about 90%. The positive structural coupling of lag-torsion was appeared with tip droop, the 2/rev lag modal frequency was decreased, the 1/rev torsion modal damping ratio was maximally decreased about 62%. The torsion stability was sharply decreased with tip sweep and droop design.
{"title":"Aeroelastic stability analysis of rotor blade with complex three-dimensional design","authors":"Jinghui Deng, Zhi-Peng Yu, Yun-Feng Zhou, Bin Song","doi":"10.1051/jnwpu/20234110209","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110209","url":null,"abstract":"A rotor dynamic analysis method for the complex three-dimensional design blade was developed and applied to analyzing its aeroelastic stability. Based on the medium-size deformation beam theory and Hamilton principle, the joint transfer matrix was used in the blade kinematic and the deformation compatibility principle was used in the assembled finite element matrix to develop the complex three-dimensional rotor structural dynamics model. The BO105 rotor was used to validate this method and the aeroelastic characteristic of the complex three-dimensional rotor was analyzed in detail. The results showed that the negative structural coupling of flap-torsion was appeared with tip sweep, and the 1/rev torsion modal frequency was decreased, and the 1/rev torsion modal damping ratio was maximally decreased about 90%. The positive structural coupling of lag-torsion was appeared with tip droop, the 2/rev lag modal frequency was decreased, the 1/rev torsion modal damping ratio was maximally decreased about 62%. The torsion stability was sharply decreased with tip sweep and droop design.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46456723","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110125
Shuhua Hou, Xuan Zhao, Zengli Liu, Yi Peng, Na Wang
Sparse linear array is prone to element failure affected by environmental and other factors in practical application, resulting in the decline of degrees of freedom and the attenuation or even failure of direction of arrival (DOA) estimation performance. To address this problem, a ternary redundant sparse array composed of three uniform linear arrays with different spacings at specific distances is designed, and the analytical expression of its degrees of freedom is derived. The configuration rules of the array are concise, and the difference coarrays of the array are hole-free. Mathematically proves that all virtual array elements can be covered with a weight of not less than 3 except the 4 farthest. The array has lower sensors importance and less generalized k-fragility. The array design takes into account the maximum degrees of freedom, redundancy and sparsity. In case of sensors failure, compared with the other sparse linear arrays, the array has more stable difference coarrays and higher uniform degrees of freedom. Compared with multiple-fold redundancy arrays, the array has lower mutual coupling. Simulation results show that the ternary redundant array has superior robustness and higher DOA estimation accuracy under sensors failure.
{"title":"Ternary redundant sparse linear array design with high robustness","authors":"Shuhua Hou, Xuan Zhao, Zengli Liu, Yi Peng, Na Wang","doi":"10.1051/jnwpu/20234110125","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110125","url":null,"abstract":"Sparse linear array is prone to element failure affected by environmental and other factors in practical application, resulting in the decline of degrees of freedom and the attenuation or even failure of direction of arrival (DOA) estimation performance. To address this problem, a ternary redundant sparse array composed of three uniform linear arrays with different spacings at specific distances is designed, and the analytical expression of its degrees of freedom is derived. The configuration rules of the array are concise, and the difference coarrays of the array are hole-free. Mathematically proves that all virtual array elements can be covered with a weight of not less than 3 except the 4 farthest. The array has lower sensors importance and less generalized k-fragility. The array design takes into account the maximum degrees of freedom, redundancy and sparsity. In case of sensors failure, compared with the other sparse linear arrays, the array has more stable difference coarrays and higher uniform degrees of freedom. Compared with multiple-fold redundancy arrays, the array has lower mutual coupling. Simulation results show that the ternary redundant array has superior robustness and higher DOA estimation accuracy under sensors failure.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44520860","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110073
Bailin Wan, Qi Yang, Zhongjiang Yan, Mao Yang, Bo Li
In order to minimize the maximum weighted response time for any node in the network to reach the central control node, a central control node election algorithm based on dynamic programming is proposed. Firstly, the response times of nodes and links in the wireless network are modeled as the node weights and edge weights in the network topology, and then the central control node election problem that minimizes the maximum weighted response time for any node in the network to reach the central control node is modeled as the central problem, where represents the number of central control nodes. Then, by using the interpolation method based on dynamic programming, the weighted response time between the two points can be obtained, and the K-central problem modeled is transformed into several R-control set problems. Then, several control R-set problems are transformed into several 0-1 integer programming problems, and each integer programming problem can be solved one by one by using the branch and bound method. Finally, a simplified implementation method based on the above algorithm is given when K=1, the optimality of the proposed algorithm is proved and the complexity of the algorithm is analyzed. Simulation results show that the proposed central control algorithm can minimize the maximum weighted response time of the network.
{"title":"Central node selection algorithm of minimizing maximum weighted response time based on dynamic programming","authors":"Bailin Wan, Qi Yang, Zhongjiang Yan, Mao Yang, Bo Li","doi":"10.1051/jnwpu/20234110073","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110073","url":null,"abstract":"In order to minimize the maximum weighted response time for any node in the network to reach the central control node, a central control node election algorithm based on dynamic programming is proposed. Firstly, the response times of nodes and links in the wireless network are modeled as the node weights and edge weights in the network topology, and then the central control node election problem that minimizes the maximum weighted response time for any node in the network to reach the central control node is modeled as the central problem, where represents the number of central control nodes. Then, by using the interpolation method based on dynamic programming, the weighted response time between the two points can be obtained, and the K-central problem modeled is transformed into several R-control set problems. Then, several control R-set problems are transformed into several 0-1 integer programming problems, and each integer programming problem can be solved one by one by using the branch and bound method. Finally, a simplified implementation method based on the above algorithm is given when K=1, the optimality of the proposed algorithm is proved and the complexity of the algorithm is analyzed. Simulation results show that the proposed central control algorithm can minimize the maximum weighted response time of the network.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47146877","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 effectively utilize the tidal current energy in offshore wind farms, a swing oscillating hydrofoil system for tidal current energy capture is proposed. The system is constructed with oscillating hydrofoils as tidal current energy capture device combined with offshore wind turbine underwater tower. Lattice Boltzmann method and large eddy simulation method were combined, and the hydrodynamic characteristics and energy collection efficiency of a NACA0015 airfoil with different motion parameters were numerically analyzed with or without the influence of tower wake. The influence of pitch amplitude, heave amplitude and chord length of the hydrofoil on the energy collection efficiency of the system is analyzed from the aspect of vortex structure in the moving process. The results show that the energy collection efficiency of the oscillating wing is significantly improved by the trailing vortex of the tower, and the vortex shedding behind the tower can reduced by the addition of the oscillating wing, consequently, the fatigue load caused by the flow around the cylindrical body can be reduced. The energy capture efficiency of the oscillating wing can reach a highest efficiently of 30.72% in the wake vortex region of the tower, which has obvious advantages compared with the traditional oscillating wing tidal current energy capture device, and provides an effective way to improve the overall energy utilization rate of offshore wind farms.
{"title":"Hydrodynamic performance analysis of tower wake vortex tidal current energy capture system with swing oscillating hydrofoil","authors":"Weijun Zhu, Shuqing Zhuang, Dongyang Chen, Jiufa Cao, Shifeng Fu, Zhenye Sun","doi":"10.1051/jnwpu/20234110188","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110188","url":null,"abstract":"In order to effectively utilize the tidal current energy in offshore wind farms, a swing oscillating hydrofoil system for tidal current energy capture is proposed. The system is constructed with oscillating hydrofoils as tidal current energy capture device combined with offshore wind turbine underwater tower. Lattice Boltzmann method and large eddy simulation method were combined, and the hydrodynamic characteristics and energy collection efficiency of a NACA0015 airfoil with different motion parameters were numerically analyzed with or without the influence of tower wake. The influence of pitch amplitude, heave amplitude and chord length of the hydrofoil on the energy collection efficiency of the system is analyzed from the aspect of vortex structure in the moving process. The results show that the energy collection efficiency of the oscillating wing is significantly improved by the trailing vortex of the tower, and the vortex shedding behind the tower can reduced by the addition of the oscillating wing, consequently, the fatigue load caused by the flow around the cylindrical body can be reduced. The energy capture efficiency of the oscillating wing can reach a highest efficiently of 30.72% in the wake vortex region of the tower, which has obvious advantages compared with the traditional oscillating wing tidal current energy capture device, and provides an effective way to improve the overall energy utilization rate of offshore wind farms.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44210290","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110028
Yu Zhang, J. Bai, Feng Qu
This paper studies several problems that may exist in the aerodynamic design of low Mach number general aircraft, and discusses the design characteristics of the pressure distribution of some related airfoils while part of the characteristics is verified by a multi-point laminar airfoil design case. Firstly, several issues which exist in the aerodynamic design of low Mach number general aircraft, such as relatively large zero-lift drag coefficient, high stall performance requirements, and large variation range of Reynolds number, are discussed and analyzed. Then, to address these issues, the paper extracts some useful design features that are beneficial to the airfoil aerodynamic performance from the study on the design characteristics of the pressure distribution of several turbulent flow airfoils and laminar flow airfoils that are designed for low Mach number general aircraft. Finally, by considering the typical design conditions of a light multi-purpose single-turboprop-engine general aircraft, including the cruise, climb and stall conditions, a multi-point laminar airfoil optimization is offered by using the GAW-1 airfoil as the baseline. The optimized foil has a 9.6 improvement in the lift-to-drag ratio of the cruise condition, a 16.3 improvement in the lift-to-drag ratio of the climb condition but a 0.115 decrease in the maximum lift coefficient of the stall condition. The results show that the requirements from the cruise, climb and stall conditions are contradictory to some degree in the considering multi-point optimization case, and the designers should deal with this trade-off carefully based on the features of the low Mach number general aircraft.
{"title":"Study on design characteristics of airfoil pressure distribution for low Mach number general aircraft","authors":"Yu Zhang, J. Bai, Feng Qu","doi":"10.1051/jnwpu/20234110028","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110028","url":null,"abstract":"This paper studies several problems that may exist in the aerodynamic design of low Mach number general aircraft, and discusses the design characteristics of the pressure distribution of some related airfoils while part of the characteristics is verified by a multi-point laminar airfoil design case. Firstly, several issues which exist in the aerodynamic design of low Mach number general aircraft, such as relatively large zero-lift drag coefficient, high stall performance requirements, and large variation range of Reynolds number, are discussed and analyzed. Then, to address these issues, the paper extracts some useful design features that are beneficial to the airfoil aerodynamic performance from the study on the design characteristics of the pressure distribution of several turbulent flow airfoils and laminar flow airfoils that are designed for low Mach number general aircraft. Finally, by considering the typical design conditions of a light multi-purpose single-turboprop-engine general aircraft, including the cruise, climb and stall conditions, a multi-point laminar airfoil optimization is offered by using the GAW-1 airfoil as the baseline. The optimized foil has a 9.6 improvement in the lift-to-drag ratio of the cruise condition, a 16.3 improvement in the lift-to-drag ratio of the climb condition but a 0.115 decrease in the maximum lift coefficient of the stall condition. The results show that the requirements from the cruise, climb and stall conditions are contradictory to some degree in the considering multi-point optimization case, and the designers should deal with this trade-off carefully based on the features of the low Mach number general aircraft.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44302297","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110198
Chunlei Li, Zhiyong Chang, Liang Li
Manufacturing enterprises will accumulate a large number of manufacturing instances as they run and develop. Being able to excavate and reuse the instance resources reasonably is one of the most effective ways to improve manufacturing and support innovation. To determine the reuse object scientifically and raise the reuse flexibility, a novel system for discovery and reuse of typical process route based on the information entropy and PSO-Kmeans clustering algorithm is proposed in this paper. In this system, a similarity measurement method of machining process routes based on the information entropy of multistage longest common subsequence is developed. Then a discovery method of typical process route based on the spectral clustering idea and PSO-Kmeans clustering algorithm is invented, and the two reuse approaches based on the typical process route are analyzed and discussed. Finally, the three case studies are rendered and the results reveal that the proposed system can provide better support for manufacture instance reuse.
{"title":"A novel system for discovery and reuse of typical process route based on information entropy and PSO-Kmeans clustering algorithm","authors":"Chunlei Li, Zhiyong Chang, Liang Li","doi":"10.1051/jnwpu/20234110198","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110198","url":null,"abstract":"Manufacturing enterprises will accumulate a large number of manufacturing instances as they run and develop. Being able to excavate and reuse the instance resources reasonably is one of the most effective ways to improve manufacturing and support innovation. To determine the reuse object scientifically and raise the reuse flexibility, a novel system for discovery and reuse of typical process route based on the information entropy and PSO-Kmeans clustering algorithm is proposed in this paper. In this system, a similarity measurement method of machining process routes based on the information entropy of multistage longest common subsequence is developed. Then a discovery method of typical process route based on the spectral clustering idea and PSO-Kmeans clustering algorithm is invented, and the two reuse approaches based on the typical process route are analyzed and discussed. Finally, the three case studies are rendered and the results reveal that the proposed system can provide better support for manufacture instance reuse.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41923337","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}
Pub Date : 2023-02-01DOI: 10.1051/jnwpu/20234110180
Jiangshan Du, T. Huang, Kaihao Wang
The soft soil pressure bearing mathematical model under repeated normal load is established and its program is implemented. The relationship of soft soil between pressure and settlement under repeated load is solved. Taking the settlement volume, contact area and loading times as independent variables and soil deformation force as dependent variables, the calculus equation of soil deformation force at the arbitrary position is deduced. The soil is discretized section by section in the settlement direction, and the bearing coefficient of the corresponding section is applied. During the unloading-loading period, the calculation formulas of the corresponding stable point and the stiffness of the soil rebounding line are given, and the load settlement program of soft soil is compiled. The soil stiffness value is substituted into the calculus equation, and the Adams software is redeveloped with C/C++language to obtain the load settlement curve. On the soft soil terrain, three kinds of flat plates with diameters of 6, 8, and 10 cm are used to carry out the pressure penetration test to obtain the corresponding pressure-settlement curve. The error between the simulation and experimental results of the mathematical model is no more than 10%.
{"title":"A calculation method of soft soil pressure bearing mathematical model under repeated load","authors":"Jiangshan Du, T. Huang, Kaihao Wang","doi":"10.1051/jnwpu/20234110180","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110180","url":null,"abstract":"The soft soil pressure bearing mathematical model under repeated normal load is established and its program is implemented. The relationship of soft soil between pressure and settlement under repeated load is solved. Taking the settlement volume, contact area and loading times as independent variables and soil deformation force as dependent variables, the calculus equation of soil deformation force at the arbitrary position is deduced. The soil is discretized section by section in the settlement direction, and the bearing coefficient of the corresponding section is applied. During the unloading-loading period, the calculation formulas of the corresponding stable point and the stiffness of the soil rebounding line are given, and the load settlement program of soft soil is compiled. The soil stiffness value is substituted into the calculus equation, and the Adams software is redeveloped with C/C++language to obtain the load settlement curve. On the soft soil terrain, three kinds of flat plates with diameters of 6, 8, and 10 cm are used to carry out the pressure penetration test to obtain the corresponding pressure-settlement curve. The error between the simulation and experimental results of the mathematical model is no more than 10%.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57899146","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}
Contrapose the highly integrated, complex working conditions and many kinds of faults of aircraft electro hydrostatic actuator(EHA), to diagnose the typical fault of EHA effectively, a fault diagnosis algorithm based on convolutional neural networks (CNN) and support vector machine(SVM) was proposed. Firstly, the fault date sets are entered on CNN for adaptive feature extraction, then the output of the fully connected layer of CNN are classified by using SVM. To improve the performance of SVM, dynamic inertia weight adaptive particle swarm optimization (IWAPSO) was used to optimize the SVM parameters. Finally, the sensitivity of SVM to noise was reduced by introducing ramp loss function. The results show that the accuracy of SVM after parameter optimization is 12.6% higher than that of standard SVM and 17.3% higher than CNN. The SVM based on the ramp loss function showed better robustness when using noisy test sets.
{"title":"Study on fault diagnosis algorithms of EHA based on CNN-SVM","authors":"Xudong Li, Yanjun Li, Yuyuan Cao, Xingye Wang, Shixuan Duan, Zejian Zhao","doi":"10.1051/jnwpu/20234110230","DOIUrl":"https://doi.org/10.1051/jnwpu/20234110230","url":null,"abstract":"Contrapose the highly integrated, complex working conditions and many kinds of faults of aircraft electro hydrostatic actuator(EHA), to diagnose the typical fault of EHA effectively, a fault diagnosis algorithm based on convolutional neural networks (CNN) and support vector machine(SVM) was proposed. Firstly, the fault date sets are entered on CNN for adaptive feature extraction, then the output of the fully connected layer of CNN are classified by using SVM. To improve the performance of SVM, dynamic inertia weight adaptive particle swarm optimization (IWAPSO) was used to optimize the SVM parameters. Finally, the sensitivity of SVM to noise was reduced by introducing ramp loss function. The results show that the accuracy of SVM after parameter optimization is 12.6% higher than that of standard SVM and 17.3% higher than CNN. The SVM based on the ramp loss function showed better robustness when using noisy test sets.","PeriodicalId":39691,"journal":{"name":"西北工业大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46864935","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：