A 3-DOF ultrasonic motor with a cylinder-shaped stator and a spherical rotor is developed. The motor provides 3-DOF rotation around x, y, and z-axes implemented by two second order bending modes with orthogonality an...A 3-DOF ultrasonic motor with a cylinder-shaped stator and a spherical rotor is developed. The motor provides 3-DOF rotation around x, y, and z-axes implemented by two second order bending modes with orthogonality and one first order longitudinal mode of the stator. The three modes must satisfy some conditions. In our previous research, in order to satisfy these conditions, a parameter fitting design method is used. However, it is an experiential design method with low efficiency and costs much time, sometimes it even cannot find a desired solution. This paper puts forward an optimal design method for the stator. Based on the method, an optimization program is developed in MATLAB environment. Using the program, a new prototype of 3-DOF ultrasonic motor is designed. Its stator has diameter of 20 mm, height of 67 mm, and mass of 157 g. Experimental results show that the measured stators′ modal frequencies and modal shapes are in good consistent agreement with the results obtained by the optimal design program.展开更多
A new method for optimizing a butterfly-shaped linear ultrasonic motor was proposed to maximize its mechanical output. The finite element analysis technology and response surface methodology were combined together to ...A new method for optimizing a butterfly-shaped linear ultrasonic motor was proposed to maximize its mechanical output. The finite element analysis technology and response surface methodology were combined together to realize the optimal design of the butterfly-shaped linear ultrasonic motor. First, the operation principle of the motor was introduced. Second, the finite element parameterized model of the stator of the motor was built using ANSYS parametric design language and some structure parameters of the stator were selected as design variables. Third, the sample points were selected in design variable space using latin hypercube Design. Through modal analysis and harmonic response analysis of the stator based on these sample points, the target responses were obtained. These sample points and response values were combined together to build a response surface model. Finally, the simplex method was used to find the optimal solution. The experimental results showed that many aspects of the design requirements of the butterfly-shaped linear ultrasonic motor have been fulfilled. The prototype motor fabricated based on the optimal design result exhibited considerably high dynamic performance, such as no-load speed of 873 ram/s, maximal thrust of 27.5 N, maximal efficiency of 43%, and thrust-weight ratio of 45.8.展开更多
A shear wave electromagnetic acoustic transducer(EMAT)optimized structure is proposed by using circumferential annular Halbach magnet structure.Based on the orthogonal test,the effects of the coil conductor width,the ...A shear wave electromagnetic acoustic transducer(EMAT)optimized structure is proposed by using circumferential annular Halbach magnet structure.Based on the orthogonal test,the effects of the coil conductor width,the spacing between adjacent conductors,the number of turns and the lifting distance on EMAT energy conversion effect are studied,and the optimal parameter combination is given.The structural design of the Halbach magnet is proposed.The cost coefficient S of the Halbach structure is defined,and the optimal thickness of auxiliary magnetic pole is obtained.The optimized EMAT coil diameter is reduced by 35%and the echo signal strength is significantly improved.Finally,C-scan imaging is carried out on the sample to verify the detection ability of EMAT.展开更多
The variance-dependent Goldstein radar interferogram filter takes into account the information of both interferometric coherence and multilook factors,and can produce very consistent results for interferograms generat...The variance-dependent Goldstein radar interferogram filter takes into account the information of both interferometric coherence and multilook factors,and can produce very consistent results for interferograms generated under a wide variety of multilook factors and with very different noise level.However,the filter is a bit complicated and its application is still very limited.We present the designing and implementation of the variance-dependent Goldstein radar interferogram filtering,emphasizing on the logic flow,the generation of look-up table,the determination of filtering parameter,and the handling of edge information loss.Experiments with real interferograms are provided to demonstrate the applications of the designed filtering.Comparisons with the result of the coherence-dependent Goldstein filter show that improvements from 18.4% to 36.9% are achieved when the variance-dependent filter is used,and the noisier the interferogram,the greater the improvement.展开更多
A three degree-of-freedom (DOF) ultrasonic motor (USM) with a cylinder-shaped stator and a spherical rotor is introduced, which uses one first order longitudinal and two second order bending nature vibration modes of ...A three degree-of-freedom (DOF) ultrasonic motor (USM) with a cylinder-shaped stator and a spherical rotor is introduced, which uses one first order longitudinal and two second order bending nature vibration modes of the cylinder. Control strategies for the two DOF trajectory following are studied and applied to the prototype USM. Vibration amplitude control is employed for speed regulation. The first trajectory following strategy is a step-by-step interpolation. The second strategy is vector decomposition control. Three pulse width modulation (PWM) methods for the exciting voltage regulation are investigated. These methods are compared and verified by several experiments. The key is to keep the phase differences of the three vibration constants and small exciting voltage distortion while the exciting voltages are changed for simplifing the control process and obtaining good control performance. The vector control method has advantages of small trajectory following error, smooth moving and low noise.展开更多
This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by th...This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by the Lorentz force between the eddy current and the static magnetic field by the magnets. From the experimental result on self-prepared EMATs, the intensity and the directivity of the transmitted wave depend on the widths of the coil and the magnets. By means of EEM analysis the authors attempt to determine the optimal values of the above widths such that both the intensity and the directivity achieve the maximum or allowable performance.展开更多
文摘A 3-DOF ultrasonic motor with a cylinder-shaped stator and a spherical rotor is developed. The motor provides 3-DOF rotation around x, y, and z-axes implemented by two second order bending modes with orthogonality and one first order longitudinal mode of the stator. The three modes must satisfy some conditions. In our previous research, in order to satisfy these conditions, a parameter fitting design method is used. However, it is an experiential design method with low efficiency and costs much time, sometimes it even cannot find a desired solution. This paper puts forward an optimal design method for the stator. Based on the method, an optimization program is developed in MATLAB environment. Using the program, a new prototype of 3-DOF ultrasonic motor is designed. Its stator has diameter of 20 mm, height of 67 mm, and mass of 157 g. Experimental results show that the measured stators′ modal frequencies and modal shapes are in good consistent agreement with the results obtained by the optimal design program.
基金Projects(51275235, 50975135) supported by the National Natural Science Foundation of ChinaProject(U0934004) supported by the Natural Science Foundation of Guangdong Province, ChinaProject(2011CB707602) supported by the National Basic Research Program of China
文摘A new method for optimizing a butterfly-shaped linear ultrasonic motor was proposed to maximize its mechanical output. The finite element analysis technology and response surface methodology were combined together to realize the optimal design of the butterfly-shaped linear ultrasonic motor. First, the operation principle of the motor was introduced. Second, the finite element parameterized model of the stator of the motor was built using ANSYS parametric design language and some structure parameters of the stator were selected as design variables. Third, the sample points were selected in design variable space using latin hypercube Design. Through modal analysis and harmonic response analysis of the stator based on these sample points, the target responses were obtained. These sample points and response values were combined together to build a response surface model. Finally, the simplex method was used to find the optimal solution. The experimental results showed that many aspects of the design requirements of the butterfly-shaped linear ultrasonic motor have been fulfilled. The prototype motor fabricated based on the optimal design result exhibited considerably high dynamic performance, such as no-load speed of 873 ram/s, maximal thrust of 27.5 N, maximal efficiency of 43%, and thrust-weight ratio of 45.8.
文摘A shear wave electromagnetic acoustic transducer(EMAT)optimized structure is proposed by using circumferential annular Halbach magnet structure.Based on the orthogonal test,the effects of the coil conductor width,the spacing between adjacent conductors,the number of turns and the lifting distance on EMAT energy conversion effect are studied,and the optimal parameter combination is given.The structural design of the Halbach magnet is proposed.The cost coefficient S of the Halbach structure is defined,and the optimal thickness of auxiliary magnetic pole is obtained.The optimized EMAT coil diameter is reduced by 35%and the echo signal strength is significantly improved.Finally,C-scan imaging is carried out on the sample to verify the detection ability of EMAT.
基金Project(2013CB733303)supported by the National Basic Research Program of ChinaProjects(41222027,11103068,41104003)supported by the National Natural Science Foundation of China+3 种基金Project(13JJ1006)supported by Hunan Provincial Natural Science Foundation,ChinaProject(TXCL-KF2013-002)supported by the Key Laboratory of Videometric and Vision Navigation of Hunan Province,ChinaProject(SKLGED2013-2-1-E)supported by the State Key Laboratory of Geodesy and Earth’s Dynamics,ChinaProject(K201208)supported by the Key Laboratory of Earth Observation Technique of National Administration of Surveying,Mapping and Geoinformation,China
文摘The variance-dependent Goldstein radar interferogram filter takes into account the information of both interferometric coherence and multilook factors,and can produce very consistent results for interferograms generated under a wide variety of multilook factors and with very different noise level.However,the filter is a bit complicated and its application is still very limited.We present the designing and implementation of the variance-dependent Goldstein radar interferogram filtering,emphasizing on the logic flow,the generation of look-up table,the determination of filtering parameter,and the handling of edge information loss.Experiments with real interferograms are provided to demonstrate the applications of the designed filtering.Comparisons with the result of the coherence-dependent Goldstein filter show that improvements from 18.4% to 36.9% are achieved when the variance-dependent filter is used,and the noisier the interferogram,the greater the improvement.
文摘A three degree-of-freedom (DOF) ultrasonic motor (USM) with a cylinder-shaped stator and a spherical rotor is introduced, which uses one first order longitudinal and two second order bending nature vibration modes of the cylinder. Control strategies for the two DOF trajectory following are studied and applied to the prototype USM. Vibration amplitude control is employed for speed regulation. The first trajectory following strategy is a step-by-step interpolation. The second strategy is vector decomposition control. Three pulse width modulation (PWM) methods for the exciting voltage regulation are investigated. These methods are compared and verified by several experiments. The key is to keep the phase differences of the three vibration constants and small exciting voltage distortion while the exciting voltages are changed for simplifing the control process and obtaining good control performance. The vector control method has advantages of small trajectory following error, smooth moving and low noise.
文摘This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by the Lorentz force between the eddy current and the static magnetic field by the magnets. From the experimental result on self-prepared EMATs, the intensity and the directivity of the transmitted wave depend on the widths of the coil and the magnets. By means of EEM analysis the authors attempt to determine the optimal values of the above widths such that both the intensity and the directivity achieve the maximum or allowable performance.
