In this paper,a magnetic field modulation model considering the influence of phase angles is established for the analysis and weakening of the cogging torque of the permanent magnet synchronous wind generations.Compar...In this paper,a magnetic field modulation model considering the influence of phase angles is established for the analysis and weakening of the cogging torque of the permanent magnet synchronous wind generations.Compared with the existing analytical model,the modulation effect of the magnetic field harmonics and phase angle on the cogging torque components is analyzed in the new model.Firstly,flux density model with phase angle characteristics is derived,and the relationship of the cogging torque and magnetic field harmonic is analyzed using energy method.Then,based on the magnetic modulation mechanism,the impact of the phase angle and magnetic field harmonics on the coupling relationship among cogging torque components is analyzed.All cogging torque components are classified as a combination of multiple positive and negative harmonic components,and the contribution characteristics of the components are determined by the harmonic combination and phase angle characteristics.Based on the finite element model(FEM),the magnetic field modulation model of the cogging torque is proved.On the basis of the conclusions obtained,it is further explained that the suppression mechanism of rotor-step skewing is a mutual complementary effect of the positive components and negative cogging components,and the main harmonic is effectively offset by selecting the seasonable of segment number and skewed angle of rotor.Finally,in order to verify the validity of the analysis method,the no-load line back EMF and cogging torque of optimized prototype is tested,and the experimental results agree well with the FEM results.展开更多
With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increas...With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets.展开更多
Cogging torque and electromagnetic vibration are two important factors for evaluating permanent magnet synchronous machine(PMSM)and are key issues that must be considered and resolved in the design and manufacture of ...Cogging torque and electromagnetic vibration are two important factors for evaluating permanent magnet synchronous machine(PMSM)and are key issues that must be considered and resolved in the design and manufacture of high-performance PMSM for electric vehicles.A fast and accurate magnetic field calculation model for interior permanent magnet synchronous machine(IPMSM)is proposed in this article.Based on the traditional magnetic potential permeance method,the stator cogging effect and complex boundary conditions of the IPMSM can be fully considered in this model,so as to realize the rapid calculation of equivalent magnetomotive force(MMF),air gap permeance,and other key electromagnetic properties.In this article,a 6-pole 36-slot IPMSM is taken as an example to establish its equivalent solution model,thereby the cogging torque is accurately calculated.And the validity of this model is verified by a variety of different magnetic pole structures,pole slot combinations machines,and prototype experiments.In addition,the improvement measure of the machine with different combination of pole arc coefficient is also studied based on this model.Cogging torque and electromagnetic vibration can be effectively weakened.Combined with the finite element model and multi-physics coupling model,the electromagnetic characteristics and vibration performance of this machine are comprehensively compared and analyzed.The analysis results have well verified its effectiveness.It can be extended to other structures or types of PMSM and has very important practical value and research significance.展开更多
Presented the methods to obtain the cogging force of permanent magnet linear synchronous motors(PMLSMs), analyzed the characteristics of the cogging force, and provided a basis for reducing the effect of the cogging f...Presented the methods to obtain the cogging force of permanent magnet linear synchronous motors(PMLSMs), analyzed the characteristics of the cogging force, and provided a basis for reducing the effect of the cogging force. 2-dimensional finite element method(2D FEM) was used to solve the whole motor when its mover was at dif- ferent position, so that the relation was derived between the cogging force and the mover position. The analysis results show that the cogging force between the two ends of the primary iron-core and the secondary permanent magnets (PMs) is sinusoidal function of the mover position under certain conditions only. Two proposed methods, namely direct and indirect methods, are applied to calculate the cogging force between the primary iron-core teeth and the secondary PMs. The agreement of the two methods is validated.展开更多
For a new type of toroidal permanent magnet linear motor(TPMLSM), this paper analyzes the thrust fluctuation in the constant acceleration operation of the motor from the Angle of the cogging force of the linear motor....For a new type of toroidal permanent magnet linear motor(TPMLSM), this paper analyzes the thrust fluctuation in the constant acceleration operation of the motor from the Angle of the cogging force of the linear motor. For the motor whose structure has been determined and processed, the structural parameters of the motor cannot be changed, and its performance cannot be improved from the perspective of the motor body.Therefore, this paper tries to consider the influence of the cogging force on the normal operation of the motor from the perspective of control. In this paper, starting from the body structure of motor, first on the annular linear motor of the cogging force characteristics were extracted, and its expression is obtained by Fourier decomposition, then investigated considering the cogging force and does not consider the cogging force control of motor model, it can be seen that the control performance deteriorates significantly after considering cogging force of the motor, and the acceleration fluctuation increases significantly during the operation of the motor. On this basis, disturbance observation algorithm is introduced, and feedforward compensation is carried out by extracting the characteristic values of the disturbance model. The results show that the disturbance observer can suppress the thrust fluctuation caused by the motor cogging force to a large extent, and it can reduce the peak-to-peak value of the thrust fluctuation by more than 85% during the motor acceleration operation.展开更多
In order to reduce the cogging torque, this paper investigates the influence of some parameters on the cogging torque developed by directly driven permanent magnet synchronous wind generators. Based on the remanent ma...In order to reduce the cogging torque, this paper investigates the influence of some parameters on the cogging torque developed by directly driven permanent magnet synchronous wind generators. Based on the remanent magnetic flux densities, the cogging torque is computed by using finite element method. It is shown that many parameters have influence on cogging torque and the slot and pole number combination has a significant effect on cogging torque. A simple factor has been introduced to indicate the effect of the slot and pole number combination. Some practical experience to reduce the cogging torque was applied to 2 MW three phase permanent magnet synchronous generator at rated speed of 37.5 rpm for wind energy conversion. The simulation and experiment results verify the effect of the proposed method.展开更多
An analytical approach is proposed for the cogging torque of a flux-switching permanent magnet machine based on the general air-gap field modulation theory. The modulation process is first investigated, and the coggin...An analytical approach is proposed for the cogging torque of a flux-switching permanent magnet machine based on the general air-gap field modulation theory. The modulation process is first investigated, and the cogging torque generation mechanism is analyzed based on the distribution of the air-gap magnetic flux density harmonics. Thus, the relationship between the air-gap field harmonics and the cogging torque is revealed, and the contribution of each harmonic to the cogging torque is calculated using the proposed method. Simultaneously, the characteristics of the cogging torque, including amplitude and frequency, are analyzed. Subsequently, the calculated cogging torque is compared with the simulated torque using finite element analysis. The two results exhibit considerable consistency, confirming the feasibility of the proposed method. Moreover, a prototype experiment is conducted, and the cogging torque is measured to verify the effectiveness of the proposed method.展开更多
Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal defo...Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal deformation of an ingot without homogenization treatment aiming at exploring a new efficient strategy of ingot cogging for superalloys.The as-cast samples were deformed at the sub-solvus temperature,and the DRX evolution from dendritic arms(DAs)to inter-dendritic regions(IDRs)was discussed based on the observation of the fishnet-like DRX microstructures and the gradient of DRX grain size at IDRs.The difference in the precipitates at DAs and IDRs played an essential role during the deformation and DRX process,which finally resulted in very different microstructures in the two areas.A selective straininduced grain boundary bulging(SIGBB)mechanism was found to function well and dominate the DRX nucleation at DAs.The grain boundary was able to migrate and bulge to nucleate on the condition that the boundary was located at DAs and had a great difference in dislocation density between its opposite sides at the same time.As for DRX nucleation at IDRs,the particle-stimulated nucleation(PSN)mechanism played a leading role,and the progressive subgrain rotation(PSR)and geometric DRX were two important supplementary mechanisms.The dislocation accumulation around the coarse precipitates at IDR resulted in progressive orientation rotation,which would generate DRX nuclei once the maximum misorientation there was sufficient to form a high-angle boundary with the matrix.The PSR or geometric DRX functioned at the severely elongated IDRs at the later stage of deformation,depending on the thickness of the elongated IDRs.The uniform microstructure was obtained by the deformation without homogenization and the subsequent annealing treatment.The smaller strain,the lower annealing temperature,and the much shorter soaking time requested in the above process lead to a smaller risk of cracking and a lower consumption of energy during the ingot-cogging process.展开更多
The influence of bread-loaf shaped magnet poles under parallel magnetization on the cogging torque of surface-mounted permanent magnet(SPM)motors is studied.For the SPM motors having magnetic poles with eccentricity a...The influence of bread-loaf shaped magnet poles under parallel magnetization on the cogging torque of surface-mounted permanent magnet(SPM)motors is studied.For the SPM motors having magnetic poles with eccentricity and sine harmonic compensation,the electromagnetic performances of integer and fractional slot motors are compared.It is found that the cogging torque and torque ripple of the integer and fractional slot motors can be reduced with the same eccentric magnet pole.The cogging torque and torque ripple of a fractional slot motor can be decreased by sine harmonic compensation,however,the same sine harmonic compensation has a small influence in integer slot motors.By varying the magnetic poles,the contribution of the field harmonics(k=(2n+1)p),which are a direct result of magnet magnetization,to the cogging torque also changes.The electromagnetic performance of a 3 kW prototype is tested,and it is found that the experimental results validate the theoretical investigation.展开更多
This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(SIPMSM)and analyzes the characteristics of SIPMSM.The series-paralle...This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(SIPMSM)and analyzes the characteristics of SIPMSM.The series-parallel equivalent magnetic circuit models(EMCMs)of SIPMSM is built based on the characteristics of magnetic circuits,which is used to design the basic electromagnetic parameters of SIPMSM.Analytical expressions of cogging torque are derived from applying analytical techniques.Stator skewed slot for cogging torque minimum is adopted,and the stator skewed slot pitch is confirmed based on the analytical expressions of the resultant cogging torque.The cogging torque,torque ripple,back electromotive force(back-EMF),power-angle characteristics,efficiency and power factor of SIPMSM are analyzed by establishing 3-dimensional finite element model(3-D-FED)of SIPMSM with stator skewed slot and straight slot.It is shown that the comprehensive performance of optimized SIPMSM is improved as confirmed by finite element analysis and analytical calculation results.展开更多
The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is h...The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.展开更多
为满足越来越多的脑卒中患者辅助行走和康复训练的需要,设计了一款下肢外骨骼机器人模型,采用D-H参数法建立踝关节、膝关节、髋关节坐标系,推演出步态周期内的坐标方程。为了安全起见,要求脑卒中患者步行速度慢且步长短,利用CoG(Center ...为满足越来越多的脑卒中患者辅助行走和康复训练的需要,设计了一款下肢外骨骼机器人模型,采用D-H参数法建立踝关节、膝关节、髋关节坐标系,推演出步态周期内的坐标方程。为了安全起见,要求脑卒中患者步行速度慢且步长短,利用CoG(Center of Gravity,重心地面投影点)作为步态规划中的稳定性判断依据,并用Robotics Toolbox for Matlab仿真,结果表明:下肢外骨骼康复机器人在康复训练过程中各关节具有连续且稳定的步态轨迹,为后续脑卒中患者使用的下肢外骨骼康复机器人样机研制提供了必要的理论依据。展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 52077142the Research Foundation of Zhengzhou Electric Power College under Grant ZEPCKY2024-01 and ZEPCKYRC01。
文摘In this paper,a magnetic field modulation model considering the influence of phase angles is established for the analysis and weakening of the cogging torque of the permanent magnet synchronous wind generations.Compared with the existing analytical model,the modulation effect of the magnetic field harmonics and phase angle on the cogging torque components is analyzed in the new model.Firstly,flux density model with phase angle characteristics is derived,and the relationship of the cogging torque and magnetic field harmonic is analyzed using energy method.Then,based on the magnetic modulation mechanism,the impact of the phase angle and magnetic field harmonics on the coupling relationship among cogging torque components is analyzed.All cogging torque components are classified as a combination of multiple positive and negative harmonic components,and the contribution characteristics of the components are determined by the harmonic combination and phase angle characteristics.Based on the finite element model(FEM),the magnetic field modulation model of the cogging torque is proved.On the basis of the conclusions obtained,it is further explained that the suppression mechanism of rotor-step skewing is a mutual complementary effect of the positive components and negative cogging components,and the main harmonic is effectively offset by selecting the seasonable of segment number and skewed angle of rotor.Finally,in order to verify the validity of the analysis method,the no-load line back EMF and cogging torque of optimized prototype is tested,and the experimental results agree well with the FEM results.
基金supported by the Natural Science Foundation of Hubei Province(No.2019 CFB759)。
文摘With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets.
基金supported in part by the National Natural Science Foundation of China under Grant 51737008.
文摘Cogging torque and electromagnetic vibration are two important factors for evaluating permanent magnet synchronous machine(PMSM)and are key issues that must be considered and resolved in the design and manufacture of high-performance PMSM for electric vehicles.A fast and accurate magnetic field calculation model for interior permanent magnet synchronous machine(IPMSM)is proposed in this article.Based on the traditional magnetic potential permeance method,the stator cogging effect and complex boundary conditions of the IPMSM can be fully considered in this model,so as to realize the rapid calculation of equivalent magnetomotive force(MMF),air gap permeance,and other key electromagnetic properties.In this article,a 6-pole 36-slot IPMSM is taken as an example to establish its equivalent solution model,thereby the cogging torque is accurately calculated.And the validity of this model is verified by a variety of different magnetic pole structures,pole slot combinations machines,and prototype experiments.In addition,the improvement measure of the machine with different combination of pole arc coefficient is also studied based on this model.Cogging torque and electromagnetic vibration can be effectively weakened.Combined with the finite element model and multi-physics coupling model,the electromagnetic characteristics and vibration performance of this machine are comprehensively compared and analyzed.The analysis results have well verified its effectiveness.It can be extended to other structures or types of PMSM and has very important practical value and research significance.
基金Supported by the National Natural Science Foundation of China (60474043)
文摘Presented the methods to obtain the cogging force of permanent magnet linear synchronous motors(PMLSMs), analyzed the characteristics of the cogging force, and provided a basis for reducing the effect of the cogging force. 2-dimensional finite element method(2D FEM) was used to solve the whole motor when its mover was at dif- ferent position, so that the relation was derived between the cogging force and the mover position. The analysis results show that the cogging force between the two ends of the primary iron-core and the secondary permanent magnets (PMs) is sinusoidal function of the mover position under certain conditions only. Two proposed methods, namely direct and indirect methods, are applied to calculate the cogging force between the primary iron-core teeth and the secondary PMs. The agreement of the two methods is validated.
基金supported in part by the National Natural Science Foundation of China under Grant 51507813。
文摘For a new type of toroidal permanent magnet linear motor(TPMLSM), this paper analyzes the thrust fluctuation in the constant acceleration operation of the motor from the Angle of the cogging force of the linear motor. For the motor whose structure has been determined and processed, the structural parameters of the motor cannot be changed, and its performance cannot be improved from the perspective of the motor body.Therefore, this paper tries to consider the influence of the cogging force on the normal operation of the motor from the perspective of control. In this paper, starting from the body structure of motor, first on the annular linear motor of the cogging force characteristics were extracted, and its expression is obtained by Fourier decomposition, then investigated considering the cogging force and does not consider the cogging force control of motor model, it can be seen that the control performance deteriorates significantly after considering cogging force of the motor, and the acceleration fluctuation increases significantly during the operation of the motor. On this basis, disturbance observation algorithm is introduced, and feedforward compensation is carried out by extracting the characteristic values of the disturbance model. The results show that the disturbance observer can suppress the thrust fluctuation caused by the motor cogging force to a large extent, and it can reduce the peak-to-peak value of the thrust fluctuation by more than 85% during the motor acceleration operation.
文摘In order to reduce the cogging torque, this paper investigates the influence of some parameters on the cogging torque developed by directly driven permanent magnet synchronous wind generators. Based on the remanent magnetic flux densities, the cogging torque is computed by using finite element method. It is shown that many parameters have influence on cogging torque and the slot and pole number combination has a significant effect on cogging torque. A simple factor has been introduced to indicate the effect of the slot and pole number combination. Some practical experience to reduce the cogging torque was applied to 2 MW three phase permanent magnet synchronous generator at rated speed of 37.5 rpm for wind energy conversion. The simulation and experiment results verify the effect of the proposed method.
基金Supported by the National Natural Science Foundation of China(U24A20147)the Postgraduate Research and Practice Innovation Program of Jiangsu Province(KYCX23_0250).
文摘An analytical approach is proposed for the cogging torque of a flux-switching permanent magnet machine based on the general air-gap field modulation theory. The modulation process is first investigated, and the cogging torque generation mechanism is analyzed based on the distribution of the air-gap magnetic flux density harmonics. Thus, the relationship between the air-gap field harmonics and the cogging torque is revealed, and the contribution of each harmonic to the cogging torque is calculated using the proposed method. Simultaneously, the characteristics of the cogging torque, including amplitude and frequency, are analyzed. Subsequently, the calculated cogging torque is compared with the simulated torque using finite element analysis. The two results exhibit considerable consistency, confirming the feasibility of the proposed method. Moreover, a prototype experiment is conducted, and the cogging torque is measured to verify the effectiveness of the proposed method.
基金supported by the Natural Science Foundation of Shaanxi Province of China(No.2023-JC-QN-0466)the National Natural Science Foundation of China(Nos.52305421 and 52175363)+1 种基金the General Research Fund of Hong Kong(No.15223520)the project No.1-ZE1W from the Hong Kong Polytechnic University.
文摘Since the as-cast microstructure benefits dynamic recrystallization(DRX)nucleation,the present research is focused on the microstructure evolution associated with the dendrites and precipitates during the thermal deformation of an ingot without homogenization treatment aiming at exploring a new efficient strategy of ingot cogging for superalloys.The as-cast samples were deformed at the sub-solvus temperature,and the DRX evolution from dendritic arms(DAs)to inter-dendritic regions(IDRs)was discussed based on the observation of the fishnet-like DRX microstructures and the gradient of DRX grain size at IDRs.The difference in the precipitates at DAs and IDRs played an essential role during the deformation and DRX process,which finally resulted in very different microstructures in the two areas.A selective straininduced grain boundary bulging(SIGBB)mechanism was found to function well and dominate the DRX nucleation at DAs.The grain boundary was able to migrate and bulge to nucleate on the condition that the boundary was located at DAs and had a great difference in dislocation density between its opposite sides at the same time.As for DRX nucleation at IDRs,the particle-stimulated nucleation(PSN)mechanism played a leading role,and the progressive subgrain rotation(PSR)and geometric DRX were two important supplementary mechanisms.The dislocation accumulation around the coarse precipitates at IDR resulted in progressive orientation rotation,which would generate DRX nuclei once the maximum misorientation there was sufficient to form a high-angle boundary with the matrix.The PSR or geometric DRX functioned at the severely elongated IDRs at the later stage of deformation,depending on the thickness of the elongated IDRs.The uniform microstructure was obtained by the deformation without homogenization and the subsequent annealing treatment.The smaller strain,the lower annealing temperature,and the much shorter soaking time requested in the above process lead to a smaller risk of cracking and a lower consumption of energy during the ingot-cogging process.
基金Supported by the Key Research and Development Program of Jiangsu Province(BE2018107).
文摘The influence of bread-loaf shaped magnet poles under parallel magnetization on the cogging torque of surface-mounted permanent magnet(SPM)motors is studied.For the SPM motors having magnetic poles with eccentricity and sine harmonic compensation,the electromagnetic performances of integer and fractional slot motors are compared.It is found that the cogging torque and torque ripple of the integer and fractional slot motors can be reduced with the same eccentric magnet pole.The cogging torque and torque ripple of a fractional slot motor can be decreased by sine harmonic compensation,however,the same sine harmonic compensation has a small influence in integer slot motors.By varying the magnetic poles,the contribution of the field harmonics(k=(2n+1)p),which are a direct result of magnet magnetization,to the cogging torque also changes.The electromagnetic performance of a 3 kW prototype is tested,and it is found that the experimental results validate the theoretical investigation.
基金Supported by National Natural Science Foundation of China(U1361109,51777060)Natural Science Foundation of Henan province(162300410117)the he innovative research team plan of Henan Polytechnic University(T2015-2).
文摘This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(SIPMSM)and analyzes the characteristics of SIPMSM.The series-parallel equivalent magnetic circuit models(EMCMs)of SIPMSM is built based on the characteristics of magnetic circuits,which is used to design the basic electromagnetic parameters of SIPMSM.Analytical expressions of cogging torque are derived from applying analytical techniques.Stator skewed slot for cogging torque minimum is adopted,and the stator skewed slot pitch is confirmed based on the analytical expressions of the resultant cogging torque.The cogging torque,torque ripple,back electromotive force(back-EMF),power-angle characteristics,efficiency and power factor of SIPMSM are analyzed by establishing 3-dimensional finite element model(3-D-FED)of SIPMSM with stator skewed slot and straight slot.It is shown that the comprehensive performance of optimized SIPMSM is improved as confirmed by finite element analysis and analytical calculation results.
文摘The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.
文摘为满足越来越多的脑卒中患者辅助行走和康复训练的需要,设计了一款下肢外骨骼机器人模型,采用D-H参数法建立踝关节、膝关节、髋关节坐标系,推演出步态周期内的坐标方程。为了安全起见,要求脑卒中患者步行速度慢且步长短,利用CoG(Center of Gravity,重心地面投影点)作为步态规划中的稳定性判断依据,并用Robotics Toolbox for Matlab仿真,结果表明:下肢外骨骼康复机器人在康复训练过程中各关节具有连续且稳定的步态轨迹,为后续脑卒中患者使用的下肢外骨骼康复机器人样机研制提供了必要的理论依据。
