In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock...In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.展开更多
A differential capacitance detection circuit aiming at detection of rotating angle in a novel levitation structure is presented. To ensure the low non-linearity and high resolution, noise analysis and non-linearity si...A differential capacitance detection circuit aiming at detection of rotating angle in a novel levitation structure is presented. To ensure the low non-linearity and high resolution, noise analysis and non-linearity simulation are conducted. In the capacitance interface, an integral charge amplifier is adopted as a front end amplifier to reduce the parasitic capacitance caused by connecting wire. For the novel differential capacitance bridge with a coupling capacitor, the noise floor and non-linearity of the detection circuit are analyzed, and the results show that the detecting circuit is capable of realizing angle detection with high angular resolution and relative low non-linearity. With a specially designed printed circuit board, the circuit is simulated by PSpice. The practical experiment shows that the detection board can achieve angular resolution as high as 0.04° with a non-linearity error 2.3%.展开更多
Tactile sensors that can detect material softness,or elastic modulus,are critical for intelligent robots and embodied neuroprosthetics.Artificial electronic skins(eSkins)that mimic the cutaneous stretchability and mec...Tactile sensors that can detect material softness,or elastic modulus,are critical for intelligent robots and embodied neuroprosthetics.Artificial electronic skins(eSkins)that mimic the cutaneous stretchability and mechanosensory apparatus can facilitate human-like touch perception in these applications.Existing devices primarily rely on the piezoresistive mechanism to detect changes in pressure and lateral strain upon contact with a target object.However,resistors are highly susceptible to changes in conductive nanomaterial morphology which compromises sample-to-sample repeatability and introduces large cyclic hysteresis.Furthermore,their fabrication and interconnection complexity hinders the development of scalable,high-density arrays.Here,we overcome these limitations with a stretchable,fully capacitive sensing array that uses rigid islands in a novel architecture to obtain multimodal information.In this configuration,normal pressure is transduced to the capacitive pixels with rigid islands while free-standing pixels increase in capacitance as a function of out-of-plane deformation induced by the softness of the touched object.Electrode dimensions and layout are investigated to determine their effect on the accurate differentiation of material moduli(72 kPa to 1.36 MPa).The sensor output trend is maintained even after a five-fold miniaturization of the array sensing area from a 25 mm to a 5 mm square.Finally,the device is integrated with a dynamic robotic gripper for real-time material classification.Our unique sensor eSkin provides sophisticated feedback while minimizing data acquisition and analysis complexity,which is advantageous for efficient training of machine learning algorithms.展开更多
Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health.Non-contact,capacitive sensing electrodes prevent potential skin iritations,and are thus beneficial for long-te...Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health.Non-contact,capacitive sensing electrodes prevent potential skin iritations,and are thus beneficial for long-term monitoring.Existing capacitive electrodes are either connected to a separate control circuit via external wires or have limited sensing capacitances,which leads to low signal qualities.This study demonstrates a stretchable capacitive sensing device with integrated electrodes and control electronics,with enhanced signal qualities.The electrodes and the control electronics are fabricated on a common fabric substrate for breathability and strain-limiting protection.The stretchable electrodes are based on an island-bridge design with a stretchability as high as-100%,and an area ratio as high as-80%.By using a dielectric calcium copper titanate(CCTO)composite as the adhesive layer,the electrode capacitance can be increased,yielding an enhanced signal-to-noise ratio(SNR)in the acquired biopotentials.This device offers a convenient and comfortable approach for long-term non-contact monitoring of biopotential signals.展开更多
A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided par...A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided parallel PCB plate allows one to measure the dielectric response of each sample through capacitive sensing technique.The measurements were based on the peak output voltage corresponding to the capacitance of the output measured by an oscilloscope with metal ions concentration of the solution varying from 0 to 10 ppm and input frequency ranging from 1 kHz to 10 MHz.The ICF of Li,Na and K in chloride solution was 2.4,2.1 and 1.9 MHz,respectively.The ICF of Na and K in hydroxide solution was 1.5 MHz and 1.1 MHz,respectively,while the ICF of Pb(NO_(3))_(2)was 490 kHz.The detected ICF was applied to further construct the portable sensor system,which is simple in design,low-cost in fabrication and easy to operate.The finding of ICF of each chemical element is necessary to solve the selectivity challenge of the capacitance-based sensor,which will be appropriate for chemical,environmental and engineering applications.展开更多
基金The National Natural Science Foundation ofChina(No.60402003)The National High Technology Research and Development Pro-gram of China(863Program)(No.2002AA745120)
文摘In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.
基金Foundation item： National Natural Science Foundation of China （60402003） The Key National Basic Research and Development Program of China （2002AA745120）
文摘A differential capacitance detection circuit aiming at detection of rotating angle in a novel levitation structure is presented. To ensure the low non-linearity and high resolution, noise analysis and non-linearity simulation are conducted. In the capacitance interface, an integral charge amplifier is adopted as a front end amplifier to reduce the parasitic capacitance caused by connecting wire. For the novel differential capacitance bridge with a coupling capacitor, the noise floor and non-linearity of the detection circuit are analyzed, and the results show that the detecting circuit is capable of realizing angle detection with high angular resolution and relative low non-linearity. With a specially designed printed circuit board, the circuit is simulated by PSpice. The practical experiment shows that the detection board can achieve angular resolution as high as 0.04° with a non-linearity error 2.3%.
基金National Science Foundation Graduate Research Fellowship,Grant No.DGE-1656518(AB)Stanford Graduate Fellowship(AB).
文摘Tactile sensors that can detect material softness,or elastic modulus,are critical for intelligent robots and embodied neuroprosthetics.Artificial electronic skins(eSkins)that mimic the cutaneous stretchability and mechanosensory apparatus can facilitate human-like touch perception in these applications.Existing devices primarily rely on the piezoresistive mechanism to detect changes in pressure and lateral strain upon contact with a target object.However,resistors are highly susceptible to changes in conductive nanomaterial morphology which compromises sample-to-sample repeatability and introduces large cyclic hysteresis.Furthermore,their fabrication and interconnection complexity hinders the development of scalable,high-density arrays.Here,we overcome these limitations with a stretchable,fully capacitive sensing array that uses rigid islands in a novel architecture to obtain multimodal information.In this configuration,normal pressure is transduced to the capacitive pixels with rigid islands while free-standing pixels increase in capacitance as a function of out-of-plane deformation induced by the softness of the touched object.Electrode dimensions and layout are investigated to determine their effect on the accurate differentiation of material moduli(72 kPa to 1.36 MPa).The sensor output trend is maintained even after a five-fold miniaturization of the array sensing area from a 25 mm to a 5 mm square.Finally,the device is integrated with a dynamic robotic gripper for real-time material classification.Our unique sensor eSkin provides sophisticated feedback while minimizing data acquisition and analysis complexity,which is advantageous for efficient training of machine learning algorithms.
基金research sponsored by Air Force Research Laboratory under agreement number FA8650-18-2-5402.
文摘Wearable biopotential sensing devices are essential to long-term and real-time monitoring of human health.Non-contact,capacitive sensing electrodes prevent potential skin iritations,and are thus beneficial for long-term monitoring.Existing capacitive electrodes are either connected to a separate control circuit via external wires or have limited sensing capacitances,which leads to low signal qualities.This study demonstrates a stretchable capacitive sensing device with integrated electrodes and control electronics,with enhanced signal qualities.The electrodes and the control electronics are fabricated on a common fabric substrate for breathability and strain-limiting protection.The stretchable electrodes are based on an island-bridge design with a stretchability as high as-100%,and an area ratio as high as-80%.By using a dielectric calcium copper titanate(CCTO)composite as the adhesive layer,the electrode capacitance can be increased,yielding an enhanced signal-to-noise ratio(SNR)in the acquired biopotentials.This device offers a convenient and comfortable approach for long-term non-contact monitoring of biopotential signals.
文摘A portable and low-cost design of parallel-plate capacitor sensor is proposed and investigated for detection of heavy and alkali metal ions concentration in liquid solution.The application of a thin and long-sided parallel PCB plate allows one to measure the dielectric response of each sample through capacitive sensing technique.The measurements were based on the peak output voltage corresponding to the capacitance of the output measured by an oscilloscope with metal ions concentration of the solution varying from 0 to 10 ppm and input frequency ranging from 1 kHz to 10 MHz.The ICF of Li,Na and K in chloride solution was 2.4,2.1 and 1.9 MHz,respectively.The ICF of Na and K in hydroxide solution was 1.5 MHz and 1.1 MHz,respectively,while the ICF of Pb(NO_(3))_(2)was 490 kHz.The detected ICF was applied to further construct the portable sensor system,which is simple in design,low-cost in fabrication and easy to operate.The finding of ICF of each chemical element is necessary to solve the selectivity challenge of the capacitance-based sensor,which will be appropriate for chemical,environmental and engineering applications.
