Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop micro-electro mechanical systems(MEMS) sensors,including pressure sensor,acceleration sensor,gas sensor,viscosit...Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop micro-electro mechanical systems(MEMS) sensors,including pressure sensor,acceleration sensor,gas sensor,viscosity & density sensor,polymerase chain reaction(PCR) chip and integrated sensor etc.This paper introduces the technologies and research results related to MEMS sensors we achieved in the last 20 years.展开更多
In the underwater environment, many visual sensors don’t work, and many sensors which work well for robots working in space or on land can not be used underwater. Therefore, an optical fiber slide tactile sensor was ...In the underwater environment, many visual sensors don’t work, and many sensors which work well for robots working in space or on land can not be used underwater. Therefore, an optical fiber slide tactile sensor was designed based on the inner modulation mechanism of optical fibers. The principles and structure of the sensor are explained in detail. Its static and dynamic characteristics were analyzed theoretically and then simulated. A dynamic characteristic model was built and the simulation made using the GA based neural network. In order to improve sensor response, the recognition model of the sensor was designed based on the ‘inverse solution’ principle of neural networks, increasing the control precision and the sensitivity of the manipulator.展开更多
Acceleration reflects vibration of a robot,and the vibration signal can reflect the operation state of the robot. Generally,detection of robot mechanical arm failure requires installing sensors on each joint. This stu...Acceleration reflects vibration of a robot,and the vibration signal can reflect the operation state of the robot. Generally,detection of robot mechanical arm failure requires installing sensors on each joint. This study proposes a method to diagnose the fault by single acceleration sensor only,which is installed at the end of the robot. The operation state of the robot is evaluated by analyzing vibration characteristics of its acceleration. First,a data acquisition function of a programmable multi-axis controller is applied to extract practical motion signals of the robot joints during operation,and practical motion signals are analyzed. Second,synthetic methods to determine acceleration of the end joints of SCARA robots in a Cartesian space is used based on the theory of the Jacobian matrix and the frequency domain of final acceleration is investigated. The relationship between end-and joint-vibration frequencies under given speeds is determined. Then,the method is verified by comparing characteristic frequencies of joint acceleration and synthetic acceleration in Cartesian coordinate system at different speeds. Finally,some faults can be diagnosed by comparing the acceleration vibration frequency extracted by a single acceleration sensor installed at the end of robot with the normal running state. Thus,this method can be used to monitor the signal variation of each joint without installing sensors on each robot joint.展开更多
There are many robotic platforms usable in the educational process. In the introduction, some of the educational platforms are presented. The main body of this paper deals with educational robotic platform iRobot Crea...There are many robotic platforms usable in the educational process. In the introduction, some of the educational platforms are presented. The main body of this paper deals with educational robotic platform iRobot Create. In this paper, main parts of this platform are described, such as mechanics, sensors and actuators. The software equipment with communication protocol of this platform is also described. The results of the analysis of this platform show its rich possibilities in its use in educational process such as mechanics, electronics and algorithms used in robotics.展开更多
Measuring the magnetic field is a common practice in industrial processes. We can cite the voltage measurements through PTs （potential transformers）. This is a classic example of inductive field measuring, predictin...Measuring the magnetic field is a common practice in industrial processes. We can cite the voltage measurements through PTs （potential transformers）. This is a classic example of inductive field measuring, predicting to be measured quantity is of oscillatory nature, with the circuit instrumentation scaled and calibrated for a typical frequency of 50/60 Hz. For a long time, only the binary information： ＂this field＂ and ＂missing field＂ is needed. For example, only with this information can we identify the frequency of the rotating shaft. Currently, new technologies employ magnetic sensors for measuring positions （distances, angles, etc.） from the intensity of the magnetic field. Inductive sensors are inefficient on measurements of static fields, such as magnets, opening spaces for new linear Hall effect sensors, and static which deal with these situations without difficulty. The present study examines the behavior of the Hall sensor, making the measurement of the intensity of the static magnetic field of the rotating magnet and the same, verifying the effect of the speed at which the magnet passes the sensor in some way alter the measurement. The results are favorable manda and the versatility of these sensors in many different applications.展开更多
A high sensitivity fiber Bragg grating pressure sensor by using mechanical amplifier is demonstrated. The measured pressure sensitivity is -1.80×10 -4 /MPa, which is about two orders of magnitude better than a si...A high sensitivity fiber Bragg grating pressure sensor by using mechanical amplifier is demonstrated. The measured pressure sensitivity is -1.80×10 -4 /MPa, which is about two orders of magnitude better than a simple monomode fiber with an in-fiber grating. The resolution of pressure measurement is 0.015 MPa based on interrogation using tunable fiber grating filter.展开更多
The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is nece...The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.展开更多
A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and...A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.展开更多
To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,wh...To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.展开更多
AE （acoustic emission） signals from concrete slab during fatigue testing with a running-wheel load were evaluated. The signals were recorded by remote sensors connected to a computer network. The sensing equipment c...AE （acoustic emission） signals from concrete slab during fatigue testing with a running-wheel load were evaluated. The signals were recorded by remote sensors connected to a computer network. The sensing equipment consisted of 60 kHz resonant-type AE sensors mounted on a reinforcing steel bar as a waveguide, together with a 16-channel sensor highway AE system. Because the detected AE signals included periodic mechanical noise from the motion of the wheel, these noises were eliminated by means of signal processing. The AE waveguide measurement over a length of 3 m detected fractures as vertical and horizontal cracks in the RC （reinforced concrete） slab. Those cracks were analyzed by correlating AE parameters with macroscopic distortions and the numbers of fatigue cycles. In the AE events and AE energy, two types of AE phenomena, active region and inactive region, were observed during fatigue testing. The vertical cracks were characterized by an AE amplitude of 58 dB, a peak frequency of 30 kHz, and a ratio of the rise time to the maximum amplitude value （RA） of 100. The horizontal cracks were characterized by an AE amplitude of 85 dB, a peak frequency of 60 kHz, and an RA value of 10.展开更多
文摘Since 1992 the author has led research group in Xi'an Jiaotong University to investigate and develop micro-electro mechanical systems(MEMS) sensors,including pressure sensor,acceleration sensor,gas sensor,viscosity & density sensor,polymerase chain reaction(PCR) chip and integrated sensor etc.This paper introduces the technologies and research results related to MEMS sensors we achieved in the last 20 years.
文摘In the underwater environment, many visual sensors don’t work, and many sensors which work well for robots working in space or on land can not be used underwater. Therefore, an optical fiber slide tactile sensor was designed based on the inner modulation mechanism of optical fibers. The principles and structure of the sensor are explained in detail. Its static and dynamic characteristics were analyzed theoretically and then simulated. A dynamic characteristic model was built and the simulation made using the GA based neural network. In order to improve sensor response, the recognition model of the sensor was designed based on the ‘inverse solution’ principle of neural networks, increasing the control precision and the sensitivity of the manipulator.
基金Supported by the National Natural Science Foundation of China(No.51775284)Natural Science Foundation of Jiangsu Province(BK20151505)Joint Research Fund for Overseas Chinese,Hong Kong and Macao Young Scholars(61728302)
文摘Acceleration reflects vibration of a robot,and the vibration signal can reflect the operation state of the robot. Generally,detection of robot mechanical arm failure requires installing sensors on each joint. This study proposes a method to diagnose the fault by single acceleration sensor only,which is installed at the end of the robot. The operation state of the robot is evaluated by analyzing vibration characteristics of its acceleration. First,a data acquisition function of a programmable multi-axis controller is applied to extract practical motion signals of the robot joints during operation,and practical motion signals are analyzed. Second,synthetic methods to determine acceleration of the end joints of SCARA robots in a Cartesian space is used based on the theory of the Jacobian matrix and the frequency domain of final acceleration is investigated. The relationship between end-and joint-vibration frequencies under given speeds is determined. Then,the method is verified by comparing characteristic frequencies of joint acceleration and synthetic acceleration in Cartesian coordinate system at different speeds. Finally,some faults can be diagnosed by comparing the acceleration vibration frequency extracted by a single acceleration sensor installed at the end of robot with the normal running state. Thus,this method can be used to monitor the signal variation of each joint without installing sensors on each robot joint.
文摘There are many robotic platforms usable in the educational process. In the introduction, some of the educational platforms are presented. The main body of this paper deals with educational robotic platform iRobot Create. In this paper, main parts of this platform are described, such as mechanics, sensors and actuators. The software equipment with communication protocol of this platform is also described. The results of the analysis of this platform show its rich possibilities in its use in educational process such as mechanics, electronics and algorithms used in robotics.
文摘Measuring the magnetic field is a common practice in industrial processes. We can cite the voltage measurements through PTs （potential transformers）. This is a classic example of inductive field measuring, predicting to be measured quantity is of oscillatory nature, with the circuit instrumentation scaled and calibrated for a typical frequency of 50/60 Hz. For a long time, only the binary information： ＂this field＂ and ＂missing field＂ is needed. For example, only with this information can we identify the frequency of the rotating shaft. Currently, new technologies employ magnetic sensors for measuring positions （distances, angles, etc.） from the intensity of the magnetic field. Inductive sensors are inefficient on measurements of static fields, such as magnets, opening spaces for new linear Hall effect sensors, and static which deal with these situations without difficulty. The present study examines the behavior of the Hall sensor, making the measurement of the intensity of the static magnetic field of the rotating magnet and the same, verifying the effect of the speed at which the magnet passes the sensor in some way alter the measurement. The results are favorable manda and the versatility of these sensors in many different applications.
基金The National Natural Science Foundation of China
文摘A high sensitivity fiber Bragg grating pressure sensor by using mechanical amplifier is demonstrated. The measured pressure sensitivity is -1.80×10 -4 /MPa, which is about two orders of magnitude better than a simple monomode fiber with an in-fiber grating. The resolution of pressure measurement is 0.015 MPa based on interrogation using tunable fiber grating filter.
文摘The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.
基金Supported by the National High Technology Research and Development Programme of China ( No. 2004AA420110)Heilongjiang Province Technology Foundation (No. GB04A502)
文摘A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.
基金Supported by the National Natural Science Foundation of China(No.11672290)
文摘To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.
文摘AE （acoustic emission） signals from concrete slab during fatigue testing with a running-wheel load were evaluated. The signals were recorded by remote sensors connected to a computer network. The sensing equipment consisted of 60 kHz resonant-type AE sensors mounted on a reinforcing steel bar as a waveguide, together with a 16-channel sensor highway AE system. Because the detected AE signals included periodic mechanical noise from the motion of the wheel, these noises were eliminated by means of signal processing. The AE waveguide measurement over a length of 3 m detected fractures as vertical and horizontal cracks in the RC （reinforced concrete） slab. Those cracks were analyzed by correlating AE parameters with macroscopic distortions and the numbers of fatigue cycles. In the AE events and AE energy, two types of AE phenomena, active region and inactive region, were observed during fatigue testing. The vertical cracks were characterized by an AE amplitude of 58 dB, a peak frequency of 30 kHz, and a ratio of the rise time to the maximum amplitude value （RA） of 100. The horizontal cracks were characterized by an AE amplitude of 85 dB, a peak frequency of 60 kHz, and an RA value of 10.
