The motor’s configuration is designed and the dynamic analysis equations based on its simplified model are deduced. A testing system utilizing grating is set up to test this new motor, and the theoretical movement pr...The motor’s configuration is designed and the dynamic analysis equations based on its simplified model are deduced. A testing system utilizing grating is set up to test this new motor, and the theoretical movement principle for the motor is proved by experiments. The pulse waveforms are applied to drive the motor to move in steps. The motor has a displacement resolution of 10 nm and a maximum velocity of 0.6 mm/s. It can drive a 200 g slider whose range is 20 mm. A one-dimensional precision positioning platform is fabricated by using the new hybrid piezoelectric motor. The prototype is made up of two servomotors and two piezoelectric motors, which are controlled automatically by a computer. The positioning range of the platform is 10 cm.展开更多
In this paper, a low-cost dualtone radio interferometric positioning system using a single mobile anchor is proposed to locate multiple targets at the same time. We name it mDRIPS. In mDRIPS, each target continuously ...In this paper, a low-cost dualtone radio interferometric positioning system using a single mobile anchor is proposed to locate multiple targets at the same time. We name it mDRIPS. In mDRIPS, each target continuously transmits a dual-tone signal with its dedicated frequencies, and the mobile anchor receives the signals at different positions along its trajectory, Neither time synchronization between the mobile anchor and the targets nor time synchronization among the targets is required. We take the instability of targets clocks into consideration and develop an ESPRIT-type algorithm to estimate frequencies of each dual-tone signal. Furthermore, the time of arrival （TOA） of each target signal is extracted from the phase estimates of the received dual-tone signals. After measuring several TOAs at different locations along the anchor＇s trajectory, each target can be located. Since the frequency difference of the two tones of each dualtone signal is designed to be smaller than the channel coherence bandwidth, the same fading effect on these two tones can be eliminated. Moreover, the integer ambiguity problem due to phase wrapping is investigated, and a localization algorithm to deal with a simplified ambiguity problem is proposed. Numerical results demonstrate the efficiency of the proposed mDRIPS.展开更多
An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based x...An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based xy-stage,electrostatics comb actuator,and a displacement sensor based on a vertical sidewall surface piezoresistor. They are all in a monolithic chip and developed using double-sided bulk-micromachining technology. The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching （DRIE） in both sides of the wafer. The detecting piezoresistor is located at the vertical sidewall surface of the detecting beam to improve the sensitivity and displacement resolution of the piezoresistive sensors using the DRIE technology combined with the ion implantation technology. The experimental results verify the integrated micro positioning xy-stage design including the micro xy-stage, electrostatics comb actuator,and the vertical sidewall surface piezoresistor technique. The sensitivity of the fabricated piezoresistive sensors is better than 1.17mV/μm without amplification and the linearity is better than 0. 814%. Under 30V driving voltage, a ± 10vm single-axis displacement is measured without crosstalk and the resonant frequency is measured at 983Hz in air.展开更多
In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of pers...In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status,the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining,a novel pattern mining algorithm,continuous route pattern mining(CRPM),is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.展开更多
When load is applied to bone,it deforms and causes fluid pressure to build up in bone.The pressure gradient between different portions of the bone microcnannels drives fluid flow through them.This kind of bone fluid f...When load is applied to bone,it deforms and causes fluid pressure to build up in bone.The pressure gradient between different portions of the bone microcnannels drives fluid flow through them.This kind of bone fluid flow can induces the streaming potentials which are considered to play a role for bone remodeling.Aimed to determine the impact of ribbed rough inner surfaces of the microchannels on the streaming potentials,streaming potentials were measured as bone fluid flowed through the mcrospaces of thin cylinder bone samples under different pressure loading rates.The results show that the streaming potentials decrease with the increase of the pressure loading rates.A digital simulation calculation was performed and the results demonstrated that there were turbulent flows near the inner wall surfaces,which making the streaming potentials smaller in bone microchannels.展开更多
文摘The motor’s configuration is designed and the dynamic analysis equations based on its simplified model are deduced. A testing system utilizing grating is set up to test this new motor, and the theoretical movement principle for the motor is proved by experiments. The pulse waveforms are applied to drive the motor to move in steps. The motor has a displacement resolution of 10 nm and a maximum velocity of 0.6 mm/s. It can drive a 200 g slider whose range is 20 mm. A one-dimensional precision positioning platform is fabricated by using the new hybrid piezoelectric motor. The prototype is made up of two servomotors and two piezoelectric motors, which are controlled automatically by a computer. The positioning range of the platform is 10 cm.
基金partially supported by the National Nature Science Foundation of China under Grants 61301223,61174127,61221003, and 61273181the Nature Science Foundation of Shanghai under Grant 13ZR1421800the New Faculty Foundation of Ministry of Education of China under Grant 13Z102090106
文摘In this paper, a low-cost dualtone radio interferometric positioning system using a single mobile anchor is proposed to locate multiple targets at the same time. We name it mDRIPS. In mDRIPS, each target continuously transmits a dual-tone signal with its dedicated frequencies, and the mobile anchor receives the signals at different positions along its trajectory, Neither time synchronization between the mobile anchor and the targets nor time synchronization among the targets is required. We take the instability of targets clocks into consideration and develop an ESPRIT-type algorithm to estimate frequencies of each dual-tone signal. Furthermore, the time of arrival （TOA） of each target signal is extracted from the phase estimates of the received dual-tone signals. After measuring several TOAs at different locations along the anchor＇s trajectory, each target can be located. Since the frequency difference of the two tones of each dualtone signal is designed to be smaller than the channel coherence bandwidth, the same fading effect on these two tones can be eliminated. Moreover, the integer ambiguity problem due to phase wrapping is investigated, and a localization algorithm to deal with a simplified ambiguity problem is proposed. Numerical results demonstrate the efficiency of the proposed mDRIPS.
文摘An integrated micro positioning xy-stage with a 2mm × 2mm-area shuttle is fabricated for application in nano- meter-scale operation and nanometric positioning precision. It is mainly composed of a silicon-based xy-stage,electrostatics comb actuator,and a displacement sensor based on a vertical sidewall surface piezoresistor. They are all in a monolithic chip and developed using double-sided bulk-micromachining technology. The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching （DRIE） in both sides of the wafer. The detecting piezoresistor is located at the vertical sidewall surface of the detecting beam to improve the sensitivity and displacement resolution of the piezoresistive sensors using the DRIE technology combined with the ion implantation technology. The experimental results verify the integrated micro positioning xy-stage design including the micro xy-stage, electrostatics comb actuator,and the vertical sidewall surface piezoresistor technique. The sensitivity of the fabricated piezoresistive sensors is better than 1.17mV/μm without amplification and the linearity is better than 0. 814%. Under 30V driving voltage, a ± 10vm single-axis displacement is measured without crosstalk and the resonant frequency is measured at 983Hz in air.
基金supported by the National Natural Science Foundation of China (No. 60703040)the Natural Science Foundation of Zheji- ang Province, China (No. Y107178)
文摘In the daily life,people often repeat regular routes in certain periods. In this paper,a mining system is developed to find the continuous route patterns of personal past trips. In order to count the diversity of personal moving status,the mining system employs the adaptive GPS data recording and five data filters to guarantee the clean trips data. The mining system uses a client/server architecture to protect personal privacy and to reduce the computational load. The server conducts the main mining procedure but with insufficient information to recover real personal routes. In order to improve the scalability of sequential pattern mining,a novel pattern mining algorithm,continuous route pattern mining(CRPM),is proposed. This algorithm can tolerate the different disturbances in real routes and extract the frequent patterns. Experimental results based on nine persons' trips show that CRPM can extract more than two times longer route patterns than the traditional route pattern mining algorithms.
基金supported by the National Natural Science Foundation of China (Grant Nos 10672119 and 10732080)
文摘When load is applied to bone,it deforms and causes fluid pressure to build up in bone.The pressure gradient between different portions of the bone microcnannels drives fluid flow through them.This kind of bone fluid flow can induces the streaming potentials which are considered to play a role for bone remodeling.Aimed to determine the impact of ribbed rough inner surfaces of the microchannels on the streaming potentials,streaming potentials were measured as bone fluid flowed through the mcrospaces of thin cylinder bone samples under different pressure loading rates.The results show that the streaming potentials decrease with the increase of the pressure loading rates.A digital simulation calculation was performed and the results demonstrated that there were turbulent flows near the inner wall surfaces,which making the streaming potentials smaller in bone microchannels.
