Objective： A novel portable and intelligent fluid resuscitation infuser is proposed in this paper. It satisfies the demands of long time use in harsh environment, such as traffic accident, natural disaster, battlefie...Objective： A novel portable and intelligent fluid resuscitation infuser is proposed in this paper. It satisfies the demands of long time use in harsh environment, such as traffic accident, natural disaster, battlefield, evacuation, pre-hospital emergency and so on. Methods： Miniature linear motor and liquid blood cartridge compose the pump body. It＇s based on the biological impedance method to measure and control, which resolve the disadvantage of traditional infuser device： large power dissipation, big size, AC power supply only and can＇t be use in field. The whole device weights 250 gram and sizes as two mobile phone together Results： Model device experiment shows： six number 7 standard AAA size alkaline batteries will run the pump for approximately 8-10 h at 6 liters per hour; IV bag can be placed at any position of patient, even under the stretcher. Conclusion： It provides accurate and reliable intravenous infusion for fwst-aid treatment in field.展开更多
We propose an inductor-capacitor(LC)wireless passive flexible accelerometer,which eliminates the difficulty in measuring the acceleration on the surface of a bending structure.The accelerometer is composed of a flexib...We propose an inductor-capacitor(LC)wireless passive flexible accelerometer,which eliminates the difficulty in measuring the acceleration on the surface of a bending structure.The accelerometer is composed of a flexible polyimide(PI)substrate and a planar spiral inductance coil(thickness 300 nm),made using micro-electro-mechanical system(MEMS)technology.It can be bent or folded at will,and can be attached firmly to the surface of objects with a bending structure.The principle of radio frequency wireless transmission is used to measure the acceleration signal by changing the distance between the accelerometer and the antenna.Compared with other accelerometers with a lead wire,the accelerometer can prevent the lead from falling off in the course of vibration,thereby prolonging its service life.Through establishment of an experimental platform,when the distance between the antenna and accelerometer was 5 mm,the characterization of the surface of bending structures demonstrated the sensing capabilities of the accelerometer at accelerations of 20-100 m/s2.The results indicate that the acceleration and peak-to-peak output voltage were nearly linear,with accelerometer sensitivity reaching 0.27 mV/(m·s-2).Moreover,the maximum error of the accelerometer was less than 0.037%.展开更多
Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechani...Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechanical system(MEMS) scanner has been utilized in photoacoustic imaging systems to enhance their performance and extend the realm of applications. The review provides a recap of recent developments in photoacoustic imaging using MEMS scanner, from instrumentation to applications. The topics include the design of MEMS scanner, its use in photoacoustic microscopy, miniature imaging probes, development of dual-modality systems,as well as cutting-edge bio-imaging studies.展开更多
This paper presents a bulk acoustic wave piezoelectric disk resonator based on a special pair of degenerative modes, to detect z-axis angular velocity. A single piezoelectric disk is operated in its appropriate modes ...This paper presents a bulk acoustic wave piezoelectric disk resonator based on a special pair of degenerative modes, to detect z-axis angular velocity. A single piezoelectric disk is operated in its appropriate modes in the k Hz frequency range to achieve this function. This design combines the bulk acoustic wave drive/sense mode with lead zirconate titanate resonator which improves device's performance and simplifies its structural complexity. The operation principle of piezoelectric disk resonator is given and validated by finite element method,and the scale factor of piezoelectric disk resonator is 0.977 μV/[(°) · s-1] without any amplification section.The results of impedance analysis for the prototype in the air, which is fabricated on lead zirconate titanate wafer by Micro-Electro-Mechanical System process, show that the resonant frequency of the piezoelectric disk resonator is about 190 k Hz. Moreover, the measured frequency split between drive and sense mode is about290 Hz without any tuning methods. At last, a closed-loop driving and detecting circuit system is designed and its modulation/demodulation method is studied, preliminary experiments show that this device is not sensitive to acceleration, but is sensitive to angular velocity, its performance parameters need follow-up experiments.展开更多
This paper addresses a nonlinear feedback control problem for the chaotic arch micro- electro-mechanical system with unknown parameters,immeasurable states and partial state-constraint subjected to the distributed ele...This paper addresses a nonlinear feedback control problem for the chaotic arch micro- electro-mechanical system with unknown parameters,immeasurable states and partial state-constraint subjected to the distributed electrostatic actuation.To reflect inherent properties and design controller, the phase diagrams,bifurcation diagram and Poincare section are presented to investigate the nonlinear dynamics.The authors employ a symmetric barrier Lyapunov function to prevent violation of constraint when the arch micro-electro-mechanical system faces some limits.An RBF neural network system integrating with an update law is adopted to estimate unknown function with arbitrarily small error. To eliminate chaotic oscillation,a neuro-adaptive backstepping control scheme fused with an extended state tracking differentiator and an observer is constructed to lower requirements on measured states and precise system model.Besides,introducing an extended state tracking differentiator avoids repeated derivative for the virtual control signal associated with conventional backstepping.Finally,simulation results are presented to illustrate feasibility of the proposed scheme.展开更多
The present paper investigates the existence of chaos in a non-autonomous fractional-order micro-electromechanical resonator system（FOMEMRS）.Using the maximal Lyapunov exponent criterion,we show that the FOMEMRS exh...The present paper investigates the existence of chaos in a non-autonomous fractional-order micro-electromechanical resonator system（FOMEMRS）.Using the maximal Lyapunov exponent criterion,we show that the FOMEMRS exhibits chaos.Strange attractors of the system are plotted to validate its chaotic behavior.Afterward,a novel fractional finite-time controller is introduced to suppress the chaos of the FOMEMRS with model uncertainties and external disturbances in a given finite time.Using the latest version of the fractional Lyapunov theory,the finite time stability and robustness of the proposed scheme are proved.Finally,we present some computer simulations to illustrate the usefulness and applicability of the proposed method.展开更多
With the development of positioning technology,loca-tion services are constantly in demand by people.As a primary location service pedestrian navigation has two main approaches based on radio and inertial navigation.T...With the development of positioning technology,loca-tion services are constantly in demand by people.As a primary location service pedestrian navigation has two main approaches based on radio and inertial navigation.The pedestrian naviga-tion based on radio is subject to environmental occlusion lead-ing to the degradation of positioning accuracy.The pedestrian navigation based on micro-electro-mechanical system inertial measurement unit(MIMU)is less susceptible to environmental interference,but its errors dissipate over time.In this paper,a chest card pedestrian navigation improvement method based on complementary correction is proposed in order to suppress the error divergence of inertial navigation methods.To suppress atti-tude errors,optimal feedback coefficients are established by pedestrian motion characteristics.To extend navigation time and improve positioning accuracy,the step length in subsequent movements is compensated by the first step length.The experi-mental results show that the positioning accuracy of the pro-posed method is improved by more than 47%and 44%com-pared with the pure inertia-based method combined with step compensation and the traditional complementary filtering com-bined method with step compensation.The proposed method can effectively suppress the error dispersion and improve the positioning accuracy.展开更多
A new switching circuit is presented for the application in the frequency range of 0 to 8 GHz. This switch is electro-thermally actuated and exhibits high radio frequency （RF） performance due to its lateral contact ...A new switching circuit is presented for the application in the frequency range of 0 to 8 GHz. This switch is electro-thermally actuated and exhibits high radio frequency （RF） performance due to its lateral contact mechanism, It composes of electroplated nickel and silicon nitride as structural materials. The isolation between bias and signal ports is realized by using silicon nitride. In the case of a small deformation, the relation between the displacement of the vertex and the pre-bending angle is analyzed. The metal contact is realized by in-plane motion and sidewall connection. The switches were fabricated using the MetalMUMPs process from MEMSCAP. The RF testing results show that the switch has a low insertion loss of 0. 9 dB at 8 GHz and a high isolation of 30 dB below 8 GHz.展开更多
3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink...3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink for DIW technology was prepared by a two-component adhesive system with waterborne polyurethane(WPU) and ethyl cellulose(EC).Not only the preparation of the explosive ink but also the principle of DIW process have been investigated systematically.The explosive ink displayed stro ng shea rthinning behavior that permitted layer-by-laye r deposition from a fine nozzle onto a substrate to produce complex shapes.The EC content was varied to alter the pore structure distribution and rheological behavior of ink samples after curing.The deposited explosive composite materials are of a honeycombed structure with high porosity,and the pore size distribution increases with the increase of EC content.No phase change was observed during the preparation process.Both WPU and EC show good compatibility with CL-20 particles.Apparently high activation energy was realized in the CL-20-based composite ink compared with that of the refined CL-20 due to the presence of non-energetic but stable WPU.The detonation performance of the composite materials can be precisely controlled by an adjustment in the content of binders.The 3D honeyco mbed CL-20 structures,which are fabricated by DIW technology,have a very small critical detonation size of less than 69 μm,as demonstrated by wedge shaped charge test.The ink can be used to create 3D structures with complex geometries not possible with traditional manufacturing techniques,which presents a bright future for the development of intelligent weapon systems.展开更多
This paper presents a high performance electric field micro sensor with combined differential structure.The sensor consists of two backward laid micro-machined chips,each packaged by polymer and metal.The novel combin...This paper presents a high performance electric field micro sensor with combined differential structure.The sensor consists of two backward laid micro-machined chips,each packaged by polymer and metal.The novel combined differential structure effectively reduces various environmental affections,such as thermal drift,humidity drift and electrostatic charge accumulation.The sensor is tested in near-ground place as well as balloon-borne sounding.In different weather conditions,the measurement results showed good agreement with those of the commercial electric field mill.展开更多
A new method to detect the magnetic field direction by using a silicon structure is presented in this paper. The structure includes a micro beam and an in-plane coil electrode. When the electrode under a magnetic fiel...A new method to detect the magnetic field direction by using a silicon structure is presented in this paper. The structure includes a micro beam and an in-plane coil electrode. When the electrode under a magnetic field is applied with an alternating current, the micro beam is actuated under the effect of the Lorentz forces. Magnetic fields of different directions cause different vibration profiles. The direction of the magnetic field is obtained by measuring the vibration amplitudes of the micro beam, which is driven to work at first- and second-order resonant modes. A micro structure has been fabricated using the bulk microma^hined silicon process. A laser Doppler vibrometer system is implemented to measure the vibration amplitudes. The experimental results show that the amplitude of the structure, which depends on the different modes, is a sine or cosine function of the angle of the magnetic field. It agrees well with the simulation result. Currently a resolution of 10~ for the magnetic field direction measurement can be obtained using the detecting principle.展开更多
The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not...The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the mi-cro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes （peak） between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear nu-merical value is more exact than linear value and the method can be applied in other mi-cro-electro-mechanical systeme （MEMS） structures to simulate the dynamic performance.展开更多
An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant fre...An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant frequency are discussed theoretically. According to the feature that impulse exists between the elastic body of composite ultrasonic linear motor and the base, an impulse analysis is presented to calculate the motor′s friction driving force and frictional conversion efficiency. The impulse analysis essentially explains the reason why the ultrasonic motor has great driving force, and can be applied to analyze the non-linear ultrasonic motor.展开更多
As actuator of the force-rebalanced servo loop, the electrostatic force generator of the micro-accelerometer shows high nonlinearity while the interpole of the micro-electro-mechanical system（MEMS） sensor is far awa...As actuator of the force-rebalanced servo loop, the electrostatic force generator of the micro-accelerometer shows high nonlinearity while the interpole of the micro-electro-mechanical system（MEMS） sensor is far away from its balance position. The control system cannot rebalance itself with the limited bandwidth after an external long overload, because the characteristics of the force generator differ from normal case. Although for similar problems, solutions with cascading lead-lag blocks, with the anti-windup（AW） technology, or with the sliding-mode control, are widely reported, the problems such as performance loss or difficulty to synthesize a digital controller still remain. Based on existing researches, remedies are developed by analyzing the characteristic of the system not only near the balance position, but also corresponding to the whole moveable range of the interpole, and a new controller is proposed. The solution is compared with the common solutions of cascading lead-lag blocks method, AW methods, and sliding mode methods. Comparison results show that the proposed solution avoid performance loss, compared to cascading lead-lag blocks solution; the proposed solution is easily synthesized and implemented in the analog servo loop of the micro-accelerometer, compared to digital AW methods; at the same time, the proposed solution avoids suffering the chattering effect problem but just utilize it, compared to the sliding-mode control solution. Nevertheless, comparison results show the solution is lack of commonality, since the solution is only more suitable to micro electrostatic force-rebalance system. The SIMULINK models with and without the proposed solution, taking typical micro-accelerometer parameters, have been set up for simulation; corresponding experiments utilizing electrometric method are also conducted after the successful simulations. Simulation and experiment results verify that the micro-accelerometer will reliably return to normal operation after external long overload with the proposed solution. Therefore, it is expected to design the analog servo loop of high performance micro electrostatic force-rebalance system so as to ensure the rebalance after long overload without performance loss.展开更多
This paper analyses the dynamic residual aberrations of a conformal optical system and introduces adaptive optics （AO） correction technology to this system. The image sharpening AO system is chosen as the correction...This paper analyses the dynamic residual aberrations of a conformal optical system and introduces adaptive optics （AO） correction technology to this system. The image sharpening AO system is chosen as the correction scheme.Communication between MATLAB and Code V is established via ActiveX technique in computer simulation.The SPGD algorithm is operated at seven zoom positions to calculate the optimized surface shape of the deformable mirror.After comparison of performance of the corrected system with the baseline system,AO technology is proved to be a good way of correcting the dynamic residual aberration in conformal optical design.展开更多
In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppr...In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppress this error at quartz level. The trimming law is obtained through the finite element method （FEM）. A femtosecond laser processing system is used to trim the gold balancing masses on the beams, and experimental results are basically consistent with the simulated ones. The mechanical quadrature error is suppressed by 96%, from 26.3° s-1 to 1.1° s-1. Nonlinearity changes from 1.48% to 0.30%, angular random walk （ARW） is reduced from 2.19° h-1/2 to 1.42° h-1/2, and bias instability is improved by a factor of 7.7, from 197.6° h-1 to 25.4° h-1.展开更多
The nonlinear interactions of a microarch resonator with 3:1 internal resonance are studied.The microarch is subjected to a combination of direct current(DC)and alternating current(AC)electric voltages.Thin piezoelect...The nonlinear interactions of a microarch resonator with 3:1 internal resonance are studied.The microarch is subjected to a combination of direct current(DC)and alternating current(AC)electric voltages.Thin piezoelectric layers are thoroughly bonded on the top and bottom surfaces of the microarch.The piezoelectric actuation is not only used to modulate the stiffness and resonance frequency of the resonator but also to provide the suitable linear frequency ratio for the activation of the internal resonance.The size effect is incorporated by using the so-called modified strain gradient theory.The system is highly nonlinear due to the co-existence of the initial curvature,the mid-plane stretching resulting from clamped anchors,and the electrostatic excitation.The eigenvalue problem is solved to conduct a frequency analysis and identify the possible regions for activating the internal resonance.The effects of the piezoelectric actuation,the electric excitation,and the small-scale effect are investigated on the internal resonance.Exclusive nonlinear phenomena such as Hopf bifurcation and hysteresis are identified in the microarch response.It is shown that by applying appropriate piezoelectric actuation,one is able to activate microarch internal resonance regardless of the initial rise level of the microarch.It is also disclosed that among all the parameters,AC electric voltage has the greatest effect on the energy exchange between the interacting modes.The results can be used to design resonators and internal resonance based micro-electro-mechanical system(MEMS)energy harvesters.展开更多
A novel on-line north-seeking method based on a three-axis micro-electro-mechanical system(MEMS)gyroscope is designed.This system processes data by using a Kalman filter to calibrate the installation error of the thre...A novel on-line north-seeking method based on a three-axis micro-electro-mechanical system(MEMS)gyroscope is designed.This system processes data by using a Kalman filter to calibrate the installation error of the three-axis MEMS gyroscope in complex environment.The attitude angle updating for quaternion,based on which the attitude instrument will be rotated in real-time and the true north will be found.Our experimental platform constitutes the dual-axis electric rotary table and the attitude instrument,which is developed independently by our scientific research team.The experimental results show that the accuracy of north-seeking is higher than 1°,while the maximum root mean square error and the maximum mean absolute error are 0.906 7 and 0.910 0,respectively.The accuracy of north-seeking is much higher than the traditional method.展开更多
基金Supported by the Second Batch of Projects of Army Medical Eleventh Five-Year Plan Research(08G084)Chongqing Key Scientific and Technological Projects(CSTC,2008AC5120)
文摘Objective： A novel portable and intelligent fluid resuscitation infuser is proposed in this paper. It satisfies the demands of long time use in harsh environment, such as traffic accident, natural disaster, battlefield, evacuation, pre-hospital emergency and so on. Methods： Miniature linear motor and liquid blood cartridge compose the pump body. It＇s based on the biological impedance method to measure and control, which resolve the disadvantage of traditional infuser device： large power dissipation, big size, AC power supply only and can＇t be use in field. The whole device weights 250 gram and sizes as two mobile phone together Results： Model device experiment shows： six number 7 standard AAA size alkaline batteries will run the pump for approximately 8-10 h at 6 liters per hour; IV bag can be placed at any position of patient, even under the stretcher. Conclusion： It provides accurate and reliable intravenous infusion for fwst-aid treatment in field.
基金Project supported by the China Aviation Development Group IndustryUniversity-Research Cooperation Project(No.HFZL2020CXY019)the Fundamental Research Program of Shanxi Province,China(No.20210302123024)the National Natural Science Foundation of China(No.51821003)。
文摘We propose an inductor-capacitor(LC)wireless passive flexible accelerometer,which eliminates the difficulty in measuring the acceleration on the surface of a bending structure.The accelerometer is composed of a flexible polyimide(PI)substrate and a planar spiral inductance coil(thickness 300 nm),made using micro-electro-mechanical system(MEMS)technology.It can be bent or folded at will,and can be attached firmly to the surface of objects with a bending structure.The principle of radio frequency wireless transmission is used to measure the acceleration signal by changing the distance between the accelerometer and the antenna.Compared with other accelerometers with a lead wire,the accelerometer can prevent the lead from falling off in the course of vibration,thereby prolonging its service life.Through establishment of an experimental platform,when the distance between the antenna and accelerometer was 5 mm,the characterization of the surface of bending structures demonstrated the sensing capabilities of the accelerometer at accelerations of 20-100 m/s2.The results indicate that the acceleration and peak-to-peak output voltage were nearly linear,with accelerometer sensitivity reaching 0.27 mV/(m·s-2).Moreover,the maximum error of the accelerometer was less than 0.037%.
基金the National Natural Science Foundation of China(No.61405112)the National High Technology Research and Development Program(863)of China(No.2015AA020944)
文摘Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechanical system(MEMS) scanner has been utilized in photoacoustic imaging systems to enhance their performance and extend the realm of applications. The review provides a recap of recent developments in photoacoustic imaging using MEMS scanner, from instrumentation to applications. The topics include the design of MEMS scanner, its use in photoacoustic microscopy, miniature imaging probes, development of dual-modality systems,as well as cutting-edge bio-imaging studies.
基金the Special New Century Excellent Talents Support Program of Ministry of Education(No.NCET-10-0583)the National Key Laboratory of Science and Technology on Nano/Micro Fabrication(No.9140C790405110C7904)+2 种基金Preresearch Fund(No.9140A09010312JW03104)Fund(No.2013ZC57003)the Graduate Innovation Program of Shanghai Jiao Tong University(No.Z-340-014)
文摘This paper presents a bulk acoustic wave piezoelectric disk resonator based on a special pair of degenerative modes, to detect z-axis angular velocity. A single piezoelectric disk is operated in its appropriate modes in the k Hz frequency range to achieve this function. This design combines the bulk acoustic wave drive/sense mode with lead zirconate titanate resonator which improves device's performance and simplifies its structural complexity. The operation principle of piezoelectric disk resonator is given and validated by finite element method,and the scale factor of piezoelectric disk resonator is 0.977 μV/[(°) · s-1] without any amplification section.The results of impedance analysis for the prototype in the air, which is fabricated on lead zirconate titanate wafer by Micro-Electro-Mechanical System process, show that the resonant frequency of the piezoelectric disk resonator is about 190 k Hz. Moreover, the measured frequency split between drive and sense mode is about290 Hz without any tuning methods. At last, a closed-loop driving and detecting circuit system is designed and its modulation/demodulation method is studied, preliminary experiments show that this device is not sensitive to acceleration, but is sensitive to angular velocity, its performance parameters need follow-up experiments.
基金supported by the National Natural Science Foundation of China under Grant Nos.51505170,51475097 and 51505045Basic and Frontier Research Program of Chongqing Municipality under Grant Nos.cstc2016jcyjA0584 and cstc2016jcyjA0441)+1 种基金Project of Introduction of Talents of Guizhou University(No.[2017]27)Key Scientific Research Program of Guizhou Province under Grant No.[2017]3001)
文摘This paper addresses a nonlinear feedback control problem for the chaotic arch micro- electro-mechanical system with unknown parameters,immeasurable states and partial state-constraint subjected to the distributed electrostatic actuation.To reflect inherent properties and design controller, the phase diagrams,bifurcation diagram and Poincare section are presented to investigate the nonlinear dynamics.The authors employ a symmetric barrier Lyapunov function to prevent violation of constraint when the arch micro-electro-mechanical system faces some limits.An RBF neural network system integrating with an update law is adopted to estimate unknown function with arbitrarily small error. To eliminate chaotic oscillation,a neuro-adaptive backstepping control scheme fused with an extended state tracking differentiator and an observer is constructed to lower requirements on measured states and precise system model.Besides,introducing an extended state tracking differentiator avoids repeated derivative for the virtual control signal associated with conventional backstepping.Finally,simulation results are presented to illustrate feasibility of the proposed scheme.
文摘The present paper investigates the existence of chaos in a non-autonomous fractional-order micro-electromechanical resonator system（FOMEMRS）.Using the maximal Lyapunov exponent criterion,we show that the FOMEMRS exhibits chaos.Strange attractors of the system are plotted to validate its chaotic behavior.Afterward,a novel fractional finite-time controller is introduced to suppress the chaos of the FOMEMRS with model uncertainties and external disturbances in a given finite time.Using the latest version of the fractional Lyapunov theory,the finite time stability and robustness of the proposed scheme are proved.Finally,we present some computer simulations to illustrate the usefulness and applicability of the proposed method.
文摘With the development of positioning technology,loca-tion services are constantly in demand by people.As a primary location service pedestrian navigation has two main approaches based on radio and inertial navigation.The pedestrian naviga-tion based on radio is subject to environmental occlusion lead-ing to the degradation of positioning accuracy.The pedestrian navigation based on micro-electro-mechanical system inertial measurement unit(MIMU)is less susceptible to environmental interference,but its errors dissipate over time.In this paper,a chest card pedestrian navigation improvement method based on complementary correction is proposed in order to suppress the error divergence of inertial navigation methods.To suppress atti-tude errors,optimal feedback coefficients are established by pedestrian motion characteristics.To extend navigation time and improve positioning accuracy,the step length in subsequent movements is compensated by the first step length.The experi-mental results show that the positioning accuracy of the pro-posed method is improved by more than 47%and 44%com-pared with the pure inertia-based method combined with step compensation and the traditional complementary filtering com-bined method with step compensation.The proposed method can effectively suppress the error dispersion and improve the positioning accuracy.
文摘A new switching circuit is presented for the application in the frequency range of 0 to 8 GHz. This switch is electro-thermally actuated and exhibits high radio frequency （RF） performance due to its lateral contact mechanism, It composes of electroplated nickel and silicon nitride as structural materials. The isolation between bias and signal ports is realized by using silicon nitride. In the case of a small deformation, the relation between the displacement of the vertex and the pre-bending angle is analyzed. The metal contact is realized by in-plane motion and sidewall connection. The switches were fabricated using the MetalMUMPs process from MEMSCAP. The RF testing results show that the switch has a low insertion loss of 0. 9 dB at 8 GHz and a high isolation of 30 dB below 8 GHz.
基金This research work was financially supported by the Advantage Disciplines Climbing Plan of Shanxi Province and Graduate Education Innovation Project in Shanxi Province(2016BY119).
文摘3D-Honeycombed CL-20 structures with low critical size of detonation have been fabricated successfully for intelligent weapon systems using a micro-flow direct ink writing(DIW) technology.The CL-20-based explosive ink for DIW technology was prepared by a two-component adhesive system with waterborne polyurethane(WPU) and ethyl cellulose(EC).Not only the preparation of the explosive ink but also the principle of DIW process have been investigated systematically.The explosive ink displayed stro ng shea rthinning behavior that permitted layer-by-laye r deposition from a fine nozzle onto a substrate to produce complex shapes.The EC content was varied to alter the pore structure distribution and rheological behavior of ink samples after curing.The deposited explosive composite materials are of a honeycombed structure with high porosity,and the pore size distribution increases with the increase of EC content.No phase change was observed during the preparation process.Both WPU and EC show good compatibility with CL-20 particles.Apparently high activation energy was realized in the CL-20-based composite ink compared with that of the refined CL-20 due to the presence of non-energetic but stable WPU.The detonation performance of the composite materials can be precisely controlled by an adjustment in the content of binders.The 3D honeyco mbed CL-20 structures,which are fabricated by DIW technology,have a very small critical detonation size of less than 69 μm,as demonstrated by wedge shaped charge test.The ink can be used to create 3D structures with complex geometries not possible with traditional manufacturing techniques,which presents a bright future for the development of intelligent weapon systems.
基金Supported by the National High Technology Research and Development Program of China(863 Program,2011AA-040405)the National Natural Science Foundation of China(Nos.61101049,61201078,61302032,61327810)
文摘This paper presents a high performance electric field micro sensor with combined differential structure.The sensor consists of two backward laid micro-machined chips,each packaged by polymer and metal.The novel combined differential structure effectively reduces various environmental affections,such as thermal drift,humidity drift and electrostatic charge accumulation.The sensor is tested in near-ground place as well as balloon-borne sounding.In different weather conditions,the measurement results showed good agreement with those of the commercial electric field mill.
基金Project supported by the National Natural Science Foundation of China (Grant No.61076071)
文摘A new method to detect the magnetic field direction by using a silicon structure is presented in this paper. The structure includes a micro beam and an in-plane coil electrode. When the electrode under a magnetic field is applied with an alternating current, the micro beam is actuated under the effect of the Lorentz forces. Magnetic fields of different directions cause different vibration profiles. The direction of the magnetic field is obtained by measuring the vibration amplitudes of the micro beam, which is driven to work at first- and second-order resonant modes. A micro structure has been fabricated using the bulk microma^hined silicon process. A laser Doppler vibrometer system is implemented to measure the vibration amplitudes. The experimental results show that the amplitude of the structure, which depends on the different modes, is a sine or cosine function of the angle of the magnetic field. It agrees well with the simulation result. Currently a resolution of 10~ for the magnetic field direction measurement can be obtained using the detecting principle.
基金This project is supported by Shanghai Municipal Science and Technique Committee Foundation, China (No. 03QF14019, No. 0452nm023, No. AM0420).
文摘The nonlinear dynamics of the lateral micro-resonator including the air damping effect is researched. The air damping force is varied periodically during the resonator oscillating, and the air damp coefficient can not be fixed as a constant. Therefore the linear dynamic analysis which used the constant air damping coefficient can not describe the actual dynamic characteristics of the mi-cro-resonator. The nonlinear dynamic model including the air damping force is established. On the base of Navier-Stokes equation and nonlinear dynamical equation, a coupled fluid-solid numerical simulation method is developed and demonstrates that damping force is a vital factor in micro-comb structures. Compared with existing experimental result, the nonlinear numerical value has quite good agreement with it. The differences of the amplitudes （peak） between the experimental data and the results by the linear model and the nonlinear model are 74.5% and 6% respectively. Nonlinear nu-merical value is more exact than linear value and the method can be applied in other mi-cro-electro-mechanical systeme （MEMS） structures to simulate the dynamic performance.
文摘An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant frequency are discussed theoretically. According to the feature that impulse exists between the elastic body of composite ultrasonic linear motor and the base, an impulse analysis is presented to calculate the motor′s friction driving force and frictional conversion efficiency. The impulse analysis essentially explains the reason why the ultrasonic motor has great driving force, and can be applied to analyze the non-linear ultrasonic motor.
基金supported by National Key Technologies R&D Program of China during the 11th Five-Year Plan (Grant No. 51309050208)
文摘As actuator of the force-rebalanced servo loop, the electrostatic force generator of the micro-accelerometer shows high nonlinearity while the interpole of the micro-electro-mechanical system（MEMS） sensor is far away from its balance position. The control system cannot rebalance itself with the limited bandwidth after an external long overload, because the characteristics of the force generator differ from normal case. Although for similar problems, solutions with cascading lead-lag blocks, with the anti-windup（AW） technology, or with the sliding-mode control, are widely reported, the problems such as performance loss or difficulty to synthesize a digital controller still remain. Based on existing researches, remedies are developed by analyzing the characteristic of the system not only near the balance position, but also corresponding to the whole moveable range of the interpole, and a new controller is proposed. The solution is compared with the common solutions of cascading lead-lag blocks method, AW methods, and sliding mode methods. Comparison results show that the proposed solution avoid performance loss, compared to cascading lead-lag blocks solution; the proposed solution is easily synthesized and implemented in the analog servo loop of the micro-accelerometer, compared to digital AW methods; at the same time, the proposed solution avoids suffering the chattering effect problem but just utilize it, compared to the sliding-mode control solution. Nevertheless, comparison results show the solution is lack of commonality, since the solution is only more suitable to micro electrostatic force-rebalance system. The SIMULINK models with and without the proposed solution, taking typical micro-accelerometer parameters, have been set up for simulation; corresponding experiments utilizing electrometric method are also conducted after the successful simulations. Simulation and experiment results verify that the micro-accelerometer will reliably return to normal operation after external long overload with the proposed solution. Therefore, it is expected to design the analog servo loop of high performance micro electrostatic force-rebalance system so as to ensure the rebalance after long overload without performance loss.
基金Project supported by the National High Technology Research and Development Program of China (Grant No 2006AA012339)
文摘This paper analyses the dynamic residual aberrations of a conformal optical system and introduces adaptive optics （AO） correction technology to this system. The image sharpening AO system is chosen as the correction scheme.Communication between MATLAB and Code V is established via ActiveX technique in computer simulation.The SPGD algorithm is operated at seven zoom positions to calculate the optimized surface shape of the deformable mirror.After comparison of performance of the corrected system with the baseline system,AO technology is proved to be a good way of correcting the dynamic residual aberration in conformal optical design.
基金Project supported by the National Natural Science Foundation of China(Grant No.61027007)
文摘In this paper, we introduce a z-axis quartz gyroscope using a double-H tuning fork, which has a high sensitivity. However, it also causes a large mechanical quadrature error. The laser trimming method is used to suppress this error at quartz level. The trimming law is obtained through the finite element method （FEM）. A femtosecond laser processing system is used to trim the gold balancing masses on the beams, and experimental results are basically consistent with the simulated ones. The mechanical quadrature error is suppressed by 96%, from 26.3° s-1 to 1.1° s-1. Nonlinearity changes from 1.48% to 0.30%, angular random walk （ARW） is reduced from 2.19° h-1/2 to 1.42° h-1/2, and bias instability is improved by a factor of 7.7, from 197.6° h-1 to 25.4° h-1.
文摘The nonlinear interactions of a microarch resonator with 3:1 internal resonance are studied.The microarch is subjected to a combination of direct current(DC)and alternating current(AC)electric voltages.Thin piezoelectric layers are thoroughly bonded on the top and bottom surfaces of the microarch.The piezoelectric actuation is not only used to modulate the stiffness and resonance frequency of the resonator but also to provide the suitable linear frequency ratio for the activation of the internal resonance.The size effect is incorporated by using the so-called modified strain gradient theory.The system is highly nonlinear due to the co-existence of the initial curvature,the mid-plane stretching resulting from clamped anchors,and the electrostatic excitation.The eigenvalue problem is solved to conduct a frequency analysis and identify the possible regions for activating the internal resonance.The effects of the piezoelectric actuation,the electric excitation,and the small-scale effect are investigated on the internal resonance.Exclusive nonlinear phenomena such as Hopf bifurcation and hysteresis are identified in the microarch response.It is shown that by applying appropriate piezoelectric actuation,one is able to activate microarch internal resonance regardless of the initial rise level of the microarch.It is also disclosed that among all the parameters,AC electric voltage has the greatest effect on the energy exchange between the interacting modes.The results can be used to design resonators and internal resonance based micro-electro-mechanical system(MEMS)energy harvesters.
基金Supported by the Chongqing International Science and Technology Cooperation Base Project(cstc2014gjhz40001)the University Achievement Transformation Project of Chongqing Science and Technology Commission(KJZH17115)+3 种基金the Basic Research Project of Chongqing Science and Technology Commission(cstc2015jcyjBX0068,cstc2014jcyjA1350,cstc2015jcyjB0360)the Dr.Start-up Fund of Chongqing University of Posts and Telecommunications(A2015-40,A2016-76)the National Natural Science Foundation of Chongqing University of Posts and Telecommunications(A2015-49)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ1704104,KJ1704091)
文摘A novel on-line north-seeking method based on a three-axis micro-electro-mechanical system(MEMS)gyroscope is designed.This system processes data by using a Kalman filter to calibrate the installation error of the three-axis MEMS gyroscope in complex environment.The attitude angle updating for quaternion,based on which the attitude instrument will be rotated in real-time and the true north will be found.Our experimental platform constitutes the dual-axis electric rotary table and the attitude instrument,which is developed independently by our scientific research team.The experimental results show that the accuracy of north-seeking is higher than 1°,while the maximum root mean square error and the maximum mean absolute error are 0.906 7 and 0.910 0,respectively.The accuracy of north-seeking is much higher than the traditional method.
