Flexible tactile sensors have broad applications in human physiological monitoring,robotic operation and human-machine interaction.However,the research of wearable and flexible tactile sensors with high sensitivity,wi...Flexible tactile sensors have broad applications in human physiological monitoring,robotic operation and human-machine interaction.However,the research of wearable and flexible tactile sensors with high sensitivity,wide sensing range and ability to detect three-dimensional(3D)force is still very challenging.Herein,a flexible tactile electronic skin sensor based on carbon nanotubes(CNTs)/polydimethylsiloxane(PDMS)nanocomposites is presented for 3D contact force detection.The 3D forces were acquired from combination of four specially designed cells in a sensing element.Contributed from the double-sided rough porous structure and specific surface morphology of nanocomposites,the piezoresistive sensor possesses high sensitivity of 12.1 kPa?1 within the range of 600 Pa and 0.68 kPa?1 in the regime exceeding 1 kPa for normal pressure,as well as 59.9 N?1 in the scope of<0.05 N and>2.3 N?1 in the region of<0.6 N for tangential force with ultra-low response time of 3.1 ms.In addition,multi-functional detection in human body monitoring was employed with single sensing cell and the sensor array was integrated into a robotic arm for objects grasping control,indicating the capacities in intelligent robot applications.展开更多
MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X...MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size （5.2 ＊ 2. 1 ＊ 1.2 em） and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.展开更多
Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive prop...Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.展开更多
During recent years,the axial-flus PMSM with contra-rotating rotors has become a hot topic in academic research due to its high efficiency and simple structure.However,its back-EMF may be distorted under the condition...During recent years,the axial-flus PMSM with contra-rotating rotors has become a hot topic in academic research due to its high efficiency and simple structure.However,its back-EMF may be distorted under the condition of different angular positions.This paper investigates characteristics of the novel motor used for contra-propeller driving.Considering the torque ripple and current oscillation under unbalanced load condition,this paper analyzes the distorted back-EMF of the machine when its two rotors get different angular positions during rotating.The analysis results are validated by transient-magnetic 3-D FEA method,which the 3-D FEA software is used to model this motor and transient simulations are carried out to obtain its magnetic characteristic and main performances.A main focus is put on the back-EMF characteristic with different angular positions between the two rotors.Furthermore,the characteristic of torque production under unbalanced load is investigated.Finally,a prototype motor is fabricated to validate the analyses of this paper.展开更多
Tactile sensors have been used for haptic perception in intelligent robotics,smart prosthetics,and human-machine interface.The development of multifunctional tactile sensor remains a challenge and limit its applicatio...Tactile sensors have been used for haptic perception in intelligent robotics,smart prosthetics,and human-machine interface.The development of multifunctional tactile sensor remains a challenge and limit its application in flexible electronics and devices.We propose a liquid metal based tactile sensor for both temperature and force sensing which is made by 3D printing.The structural design and working principle of liquid metal based tactile sensor are firstly described.A digital light processing-based printing process is developed to print two kinds of photosensitive resins with different hardness,and used to fabricate the tactile sensor.A Wheatstone bridge circuit is designed for decoupling the temperature and forces from the measured output voltages.Characterization tests show that the tactile sensor has relatively high force sensing sensitivity of 0.29 N^(-1),and temperature sensing sensitivities are 0.55%°C−1 at 20~50°C and 0.21%°C^(−1)at 50~80°C,respectively.Then,the fabricated tactile sensor is mounted onto hand finger to measure the contact force and temperature during grasping.Results show that the 3D printed tactile sensor has excellent flexibility and durability and can accurately measure the temperature and contact forces,which demonstrate its potential in robotic manipulation applications.展开更多
A knowledge-based fuzzy logic model was developed on experimental data and used to predict the draft,side and vertical forces and soil disturbance area by disc tillage tool operation.The laboratory research work was c...A knowledge-based fuzzy logic model was developed on experimental data and used to predict the draft,side and vertical forces and soil disturbance area by disc tillage tool operation.The laboratory research work was conducted to evaluate the performance of the disc tool at three working speeds(1.25 m/s,1.98 m/s and 2.47 m/s,respectively)and depths(0-5 cm,5-10 cm and 10-15 cm,respectively)on paddy soil under soil-bin environment.Further,draft(Fx),side(Fz)and vertical(Fy)forces of disc and soil disturbance area were assessed and predicted towards working speeds and depths.A fuzzy prediction model with two input variables(speed and depth)and four output variables was developed and the Mamdani inference approach was used.Draft,side and vertical forces of disc and soil disturbance area were positively responded 0.97,0.95 and 0.84 and 0.99,respectively.The prediction results showed a close relationship between measured and predicted data.Similarly,the measured and predicted results revealed that the draft,side,vertical forces,and soil disturbance area slightly increased,while increasing the speed and depth of the disc tool.Furthermore,disc forces and soil disturbed area were highly significant(p<0.05)for higher speed towards depth.It was concluded that the fuzzy model may be introduced for predicting the disc forces and soil disturbance area during the disc tillage tool operation with high accuracy.展开更多
Identification of magnitude and orientation for spatially applied loading is highly desired in the fields of not only the machinery components but also human-machine interaction.Despite the fact that the 3-axis force ...Identification of magnitude and orientation for spatially applied loading is highly desired in the fields of not only the machinery components but also human-machine interaction.Despite the fact that the 3-axis force sensor with different structures has been proposed to measure the spatial force,there are still some common limitations including the multi-step manufacturing-assembly processes and complicated testing of decoupling calibration.Here,we propose a rapid fabrication strategy with low-cost to achieve high-precision 3-axis force sensors.The sensor is designed to compose of structural Maltese cross base and sensing units.It is directly fabricated within one step by a hybrid 3D printing technology combining deposition modeling(FDM)with direct-ink-writing(DIW).In particular,a machine learning(ML)model is used to convert the strain signal to the force components.Instead of a mount of calibration tests,this ML model is trained by sufficient simulation data based on programmed batch finite element modeling.This sensor is capable of continuously identifying a spatial force with varying magnitude and orientation,which successfully quantify the applied force of traditional Chinese medicine physiotherapy including Gua Sha and massage.This work provides insight for design and rapid fabrication of multi-axis force sensors,as well as potential applications.展开更多
The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the abili...The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the ability of 3-D digital elevation models (DEMs) derived from high accurate data to assess and quantify beach morphodynamics in relation with wave forcing. The methodology and data acquisition are described and consist mainly in the production of interpolated DEMs from which a variety of representations can be made, including as elevation change maps, two-dimensional cross-sections of the beach, calculation of net volume. The results of the analysis highlight seasonal changes in beach morphology due to variations in wave energy. This behavior is characterized by beach erosion and bar decay under high-energy waves and net accretion and bar formation during relatively fair weather conditions. The sand budgets adjustments show that the loss of volume in the winter months is compensated for by accumulation to the beach during summer. This trend suggests that there is a mechanism which controls the beach evolution. The correlation between beach changes and wave energy variations highlights a net relation between them. The results from this in- vestigation state the value of DEMs utilized and demonstrate the efficiency of the 3-D approach employed here to assess the erosion and accretion patterns which would not be visualized using 2-D profiles.展开更多
A three-dimensional motion force tester for animal was used to measure the reaction forces of the feet of a Chinese toad (B. gargarizans) against a horizontal solid surface on which it crawled. The motion behavior of ...A three-dimensional motion force tester for animal was used to measure the reaction forces of the feet of a Chinese toad (B. gargarizans) against a horizontal solid surface on which it crawled. The motion behavior of the Chinese toad was recorded by a high-speed camera on line. The motor function of every foot was analyzed. It was found that the lateral force represents the control ability of side-to-side locomotion, controls the lateral movement, and maintains a stable state for the sustainable creeping gesture. The forefeet play the assistant role and the hind feet play the main role in driving. The normal force of the forefeet is significantly greater than that of the hind feet, so the forefeet play the main role in supporting the body and the hind feet play the assistant role. The normal force is significantly greater than the lateral force and the driving force as well. There is little change for the friction force and the support angle of the all four feet. The average value of the support angle is 70°–80°. The Chinese toad’s vola friction coefficient of the forefeet is less than that of the hind feet. The above results indicate that the difference in kinematics and the material characteristic of the contact skin of the Chinese toad. The results could be useful to the structure design and gait optimization of some robots.展开更多
基金funding from National Natural Science Foundation of China(NSFC Nos.61774157,81771388,61874121,and 61874012)Beijing Natural Science Foundation(No.4182075)the Capital Science and Technology Conditions Platform Project(Project ID:Z181100009518014).
文摘Flexible tactile sensors have broad applications in human physiological monitoring,robotic operation and human-machine interaction.However,the research of wearable and flexible tactile sensors with high sensitivity,wide sensing range and ability to detect three-dimensional(3D)force is still very challenging.Herein,a flexible tactile electronic skin sensor based on carbon nanotubes(CNTs)/polydimethylsiloxane(PDMS)nanocomposites is presented for 3D contact force detection.The 3D forces were acquired from combination of four specially designed cells in a sensing element.Contributed from the double-sided rough porous structure and specific surface morphology of nanocomposites,the piezoresistive sensor possesses high sensitivity of 12.1 kPa?1 within the range of 600 Pa and 0.68 kPa?1 in the regime exceeding 1 kPa for normal pressure,as well as 59.9 N?1 in the scope of<0.05 N and>2.3 N?1 in the region of<0.6 N for tangential force with ultra-low response time of 3.1 ms.In addition,multi-functional detection in human body monitoring was employed with single sensing cell and the sensor array was integrated into a robotic arm for objects grasping control,indicating the capacities in intelligent robot applications.
文摘MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size （5.2 ＊ 2. 1 ＊ 1.2 em） and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.
文摘Three-dimensional (3-D)self-assembly of nanos- tructures and nanodevices on a large scale remains a grand quest for mankind.Freestanding nanostructured assemblies with controlled 3-D shapes can exhibit attractive properties for sensor and other applications. Protocols for 3-D self-assembly that can be scaled up for mass production on a large up to tonnage)scale, while preserving morphological features on a small (down to nanometer)scale,are needed to allow for widespread use of 3-D nanostructures in advanced devices.However,these often conflicting requirements of scalability and precision pose a difficult challenge for synthetic (man-made)processing routes.
基金This work was supported in part by the National Key R&D Program of China(No.2017YFB1300900)the Natural Science Foundation of China under Grant 51577052,51707062.
文摘During recent years,the axial-flus PMSM with contra-rotating rotors has become a hot topic in academic research due to its high efficiency and simple structure.However,its back-EMF may be distorted under the condition of different angular positions.This paper investigates characteristics of the novel motor used for contra-propeller driving.Considering the torque ripple and current oscillation under unbalanced load condition,this paper analyzes the distorted back-EMF of the machine when its two rotors get different angular positions during rotating.The analysis results are validated by transient-magnetic 3-D FEA method,which the 3-D FEA software is used to model this motor and transient simulations are carried out to obtain its magnetic characteristic and main performances.A main focus is put on the back-EMF characteristic with different angular positions between the two rotors.Furthermore,the characteristic of torque production under unbalanced load is investigated.Finally,a prototype motor is fabricated to validate the analyses of this paper.
基金This work was supported by National Nature Science Foundation of China[51575485]the Natural Science Foundation of Zhejiang Province for Distinguished Young Scientists[LR19E050001]Open Fund Project of Zhejiang Laboratory[2019MC0AB02].
文摘Tactile sensors have been used for haptic perception in intelligent robotics,smart prosthetics,and human-machine interface.The development of multifunctional tactile sensor remains a challenge and limit its application in flexible electronics and devices.We propose a liquid metal based tactile sensor for both temperature and force sensing which is made by 3D printing.The structural design and working principle of liquid metal based tactile sensor are firstly described.A digital light processing-based printing process is developed to print two kinds of photosensitive resins with different hardness,and used to fabricate the tactile sensor.A Wheatstone bridge circuit is designed for decoupling the temperature and forces from the measured output voltages.Characterization tests show that the tactile sensor has relatively high force sensing sensitivity of 0.29 N^(-1),and temperature sensing sensitivities are 0.55%°C−1 at 20~50°C and 0.21%°C^(−1)at 50~80°C,respectively.Then,the fabricated tactile sensor is mounted onto hand finger to measure the contact force and temperature during grasping.Results show that the 3D printed tactile sensor has excellent flexibility and durability and can accurately measure the temperature and contact forces,which demonstrate its potential in robotic manipulation applications.
基金This work is financially supported by the National Key Research of Development Program of China(Grant No.2016YFD0702004)the National Natural Science Foundation of China(Grant No.51605196)+3 种基金the Jiangsu Key Research and Development Program of China(Grant No.BE2016356)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20160532)the National Science Foundation for Post-doctoral Scientists of China(Grant No.2016M591788)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(Grant No.17KJB416003).
文摘A knowledge-based fuzzy logic model was developed on experimental data and used to predict the draft,side and vertical forces and soil disturbance area by disc tillage tool operation.The laboratory research work was conducted to evaluate the performance of the disc tool at three working speeds(1.25 m/s,1.98 m/s and 2.47 m/s,respectively)and depths(0-5 cm,5-10 cm and 10-15 cm,respectively)on paddy soil under soil-bin environment.Further,draft(Fx),side(Fz)and vertical(Fy)forces of disc and soil disturbance area were assessed and predicted towards working speeds and depths.A fuzzy prediction model with two input variables(speed and depth)and four output variables was developed and the Mamdani inference approach was used.Draft,side and vertical forces of disc and soil disturbance area were positively responded 0.97,0.95 and 0.84 and 0.99,respectively.The prediction results showed a close relationship between measured and predicted data.Similarly,the measured and predicted results revealed that the draft,side,vertical forces,and soil disturbance area slightly increased,while increasing the speed and depth of the disc tool.Furthermore,disc forces and soil disturbed area were highly significant(p<0.05)for higher speed towards depth.It was concluded that the fuzzy model may be introduced for predicting the disc forces and soil disturbance area during the disc tillage tool operation with high accuracy.
基金supported by the National Natural Science Foundation of China [12372078]Sixth Phase of Jiangsu Province"333 High Level Talent Training Project"Second Level Talents State Key Laboratory of Mechanics and Control of Mechanical Structures (Nanjing University of Aeronautics and astronautics [MCMS-E-0422G04].
文摘Identification of magnitude and orientation for spatially applied loading is highly desired in the fields of not only the machinery components but also human-machine interaction.Despite the fact that the 3-axis force sensor with different structures has been proposed to measure the spatial force,there are still some common limitations including the multi-step manufacturing-assembly processes and complicated testing of decoupling calibration.Here,we propose a rapid fabrication strategy with low-cost to achieve high-precision 3-axis force sensors.The sensor is designed to compose of structural Maltese cross base and sensing units.It is directly fabricated within one step by a hybrid 3D printing technology combining deposition modeling(FDM)with direct-ink-writing(DIW).In particular,a machine learning(ML)model is used to convert the strain signal to the force components.Instead of a mount of calibration tests,this ML model is trained by sufficient simulation data based on programmed batch finite element modeling.This sensor is capable of continuously identifying a spatial force with varying magnitude and orientation,which successfully quantify the applied force of traditional Chinese medicine physiotherapy including Gua Sha and massage.This work provides insight for design and rapid fabrication of multi-axis force sensors,as well as potential applications.
文摘The morphological and volumetric changes of a sandy beach were investigated through a series of two- monthly filed surveys carried out aver a 2-year period from April 2005 to January 2007. This paper discuss the ability of 3-D digital elevation models (DEMs) derived from high accurate data to assess and quantify beach morphodynamics in relation with wave forcing. The methodology and data acquisition are described and consist mainly in the production of interpolated DEMs from which a variety of representations can be made, including as elevation change maps, two-dimensional cross-sections of the beach, calculation of net volume. The results of the analysis highlight seasonal changes in beach morphology due to variations in wave energy. This behavior is characterized by beach erosion and bar decay under high-energy waves and net accretion and bar formation during relatively fair weather conditions. The sand budgets adjustments show that the loss of volume in the winter months is compensated for by accumulation to the beach during summer. This trend suggests that there is a mechanism which controls the beach evolution. The correlation between beach changes and wave energy variations highlights a net relation between them. The results from this in- vestigation state the value of DEMs utilized and demonstrate the efficiency of the 3-D approach employed here to assess the erosion and accretion patterns which would not be visualized using 2-D profiles.
基金supported by the Development Foundation of Science and Technology in Jilin Province of China (Grant No 20100711)the National 985 Project in Jilin University of China and the Graduate Innovation Foundation of National 985 Project in Jilin University of China (Grant No 20080105)
文摘A three-dimensional motion force tester for animal was used to measure the reaction forces of the feet of a Chinese toad (B. gargarizans) against a horizontal solid surface on which it crawled. The motion behavior of the Chinese toad was recorded by a high-speed camera on line. The motor function of every foot was analyzed. It was found that the lateral force represents the control ability of side-to-side locomotion, controls the lateral movement, and maintains a stable state for the sustainable creeping gesture. The forefeet play the assistant role and the hind feet play the main role in driving. The normal force of the forefeet is significantly greater than that of the hind feet, so the forefeet play the main role in supporting the body and the hind feet play the assistant role. The normal force is significantly greater than the lateral force and the driving force as well. There is little change for the friction force and the support angle of the all four feet. The average value of the support angle is 70°–80°. The Chinese toad’s vola friction coefficient of the forefeet is less than that of the hind feet. The above results indicate that the difference in kinematics and the material characteristic of the contact skin of the Chinese toad. The results could be useful to the structure design and gait optimization of some robots.
