Aiming at the specific protocol of RFID technology,a 915MHz CMOS transmitter front-end for OOK modulation is implemented in a 0.18μm CMOS process. The transmitter incorporates a class-E power amplifier （PA）, a modu...Aiming at the specific protocol of RFID technology,a 915MHz CMOS transmitter front-end for OOK modulation is implemented in a 0.18μm CMOS process. The transmitter incorporates a class-E power amplifier （PA）, a modulator, and a control logic unit. The direct-conversion architecture minimizes the required on-and-off-chip components and provides a low-cost and efficient solution. A novel structure is proposed to provide the modulation depth of 100% and 18% ,respectively. The PA presents an output ldB power of 17.6dBm while maintaining a maximum PAE of 35.4%.展开更多
In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but someh...In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but somehow in between. This means that, with respect to the on\|line problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi on\|line ones. The authors studied two semi on\|line multiprocessor scheduling problems, in which, the total processing time of all tasks is known in advance, or all processing times lie in a given interval. They proposed approximation algorithms for minimizing the makespan and analyzed their performance guarantee. The algorithms improve the known results for 3 or more processor cases in the literature.展开更多
A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The prop...A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.展开更多
A novel control system is developed to improve the capabilities of robet hand performing tasks in a variety of environments. A joint impedance control strategy has been successfully implemented in the low level contro...A novel control system is developed to improve the capabilities of robet hand performing tasks in a variety of environments. A joint impedance control strategy has been successfully implemented in the low level control of a highly integrated robot hand. At flint, a real time controller with DSP＆FPGA-based multilevel control architecture is built. Then a current sensor of the single direct current （DC） link is used to measure and reconstruct the three phase currents, and a stable current signal is measured by optimizing sample instant. The experimental results of the joint impedance control show that the proposed method not only improves the effectiveness of contact environment performance, but also provides compliant interaction of robot hand with a person, which is very important for the development of friendly human robot of the next generation.展开更多
A new impedance controller based on the dynamic surface control-backstepping technique to actualize the anticipant dynamic relationship between the motion of end-effector and the external torques was presented. Compar...A new impedance controller based on the dynamic surface control-backstepping technique to actualize the anticipant dynamic relationship between the motion of end-effector and the external torques was presented. Comparing with the traditional backstepping method that has ＂explosion of terms＂ problem, the new proposed control system is a combination of the dynamic surface control technique and the backstepping. The dynamic surface control （DSC） technique can resolve the ＂explosion of terms＂ problem that is caused by differential coefficient calculation in the model, and the problem can bring a complexity that will cause the backstepping method hardly to be applied to the practical application, especially to the multi-joint robot. Finally, the validity of the method was proved in the laboratory environment that was set up on the 5-DOF （degree of freedom） flexible joint robot. Tracking errors of DSC-backstepping impedance control that were 2.0 and 1.5 mm are better than those of backstepping impedance control which were 3.5 and 2.5 mm in directions X, Y in free space, respectively. And the anticipant Cartesian impedance behavior and compliant behavior were nchieved successfully as depicted theoretically.展开更多
In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1...In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1400-2600 r/min）, ambient air temperature（2.4-17.8 ℃） and condenser water inlet temperature（30-50℃）. The results show that as engine speed increases from 1400 r/min to 2600 r/min, the total heating capacity and energy consumption increase by about 30% and 89%, respectively; while the heat pump coefficient of performance（COP） and system primary energy ratio（PER） decrease by 44% and 31%, respectively. With the increase of ambient air temperature from 2.4 ℃ to 17.8 ℃, the heat pump COP and system PER increase by 32% and 19%, respectively. Moreover, the heat pump COP and system PER decrease by 27% and 15%, respectively, when the condenser water inlet temperature changes from 30 ℃ to 50 ℃. So, it is obvious that the effect of engine speed on the performance is more significant than the effects of ambient air temperature and condenser water inlet temperature.展开更多
The control system of an autonomous underwater vehicle （AUV） is introduced. According to control requirements of the AUV, a simple but practical adaptive PID control method is designed The semi-physical simulation ...The control system of an autonomous underwater vehicle （AUV） is introduced. According to control requirements of the AUV, a simple but practical adaptive PID control method is designed The semi-physical simulation is done to test the feasibility of the control system. The neural network idea and the structure of PID controller are referred to design the adaptive PID controller. An intelligent integral is introduced to improve control precision. Compaed with traditional PID con- trollers, the adaptive PID controller has simple structure, good online adjusting ability, fast convergence and good robustness. The simulation experiments also show that the adaptive PID control system has high precision and fine antijamming ability.展开更多
This article presents the development of a robotic controller for technical training, academic teaching, and research. The controller was designed to interact from 1 to 6 DOF （degrees of freedom） serial robotic arms...This article presents the development of a robotic controller for technical training, academic teaching, and research. The controller was designed to interact from 1 to 6 DOF （degrees of freedom） serial robotic arms, actuated by brushed DC （direct current） servomotors equipped with incremental encoders. Controller architecture is based on four components： a processor, a reconfigurable FPGA （field-programmable gate array）, measurement I/O hardware and software. Functionality of the robotic controller has been proved by means of the interaction with an SCARA （selective compliance assembly robot arm）. The proposed controller presents the potential to teach technical courses （like robotics, control, electronics and programming） and to implement and validate advanced control algorithms.展开更多
A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes duri...A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.展开更多
The 3D visualization model of slop with structural plane can displayed the characters of structural plane in slop directly, and illustrated the spatial combination. It is a modem and critical question in the field of ...The 3D visualization model of slop with structural plane can displayed the characters of structural plane in slop directly, and illustrated the spatial combination. It is a modem and critical question in the field of geotechnical engineering. Based on the peculiarity of the reconnaissance and the research of the visualization by formers, systemized the method fit for building 3D visualization model of slop with structural plane. Write the special program with Visual C^-＋ computer language and illustrated it by OpenGL, the program can displayed and captured the random section plane. The program has a satisfied result by proving with the real projects.展开更多
The rapid development of superconducting nanowire single-photon detectors over the past decade has led to numerous advances in quantum information technology. The record for the best system detection efficiency at an ...The rapid development of superconducting nanowire single-photon detectors over the past decade has led to numerous advances in quantum information technology. The record for the best system detection efficiency at an incident photon wavelength of 1550 nm is 93%. This performance was attained from a superconducting nanowire single-photon detector made of amorphous WSi; such detectors are usually operated at sub-Kelvin temperatures. In this study, we first demonstrate superconducting nanowire single-photon detectors made of polycrystalline NbN with system detection efficiency of 90.2% for 1550-nm-wavelength photons at2.1 K, accessible with a compact cryocooler. The system detection efficiency saturated at 92.1% when the temperature was lowered to 1.8 K. We expect the results lighten the practical and high performance superconducting nanowire single-photon detectors to quantum information and other high-end applications.展开更多
The current work is oriented toward the development of a novel biologically inspired bat aerial robot with morphing wings. Based on the flight characteristics data of natural bats(Eptesicus fuscus), a novel four degre...The current work is oriented toward the development of a novel biologically inspired bat aerial robot with morphing wings. Based on the flight characteristics data of natural bats(Eptesicus fuscus), a novel four degrees of freedom robotic bat wing was developed to emulate the movements of bat wing. The design, fabrication, programing and wind tunnel experiments of the robot bat wing are described in this paper. Based on this robotic wing, the influence of flap amplitude, wind speed, flight frequency, downstroke ratio and stroke plane angle as well as the contributions of flap, elbow, sweep and wrist motions on the aerodynamic force and mechanical power were studied and analyzed. Results of wind tunnel experiments validated that higher lift would bring greater power consumption, and the flap motion would generate the most force and need more energy expenditure compared with other motions of bat. The experimental results suggest that the flap and fold motions are indispensable to make a robotic bat wing that has a better flight performance. This study provides some implications and a better understanding for the future robotic bat.展开更多
In this paper,we consider two-queue polling model with a Timer and a Randomly-Timed Gated(RTG) mechanism.At queue Q1,we employ a Timer T(1):whenever the server polls queue Q1 and finds it empty,it activates a Timer.If...In this paper,we consider two-queue polling model with a Timer and a Randomly-Timed Gated(RTG) mechanism.At queue Q1,we employ a Timer T(1):whenever the server polls queue Q1 and finds it empty,it activates a Timer.If a customer arrives before the Timer expires,a busy period starts in accordance with exhaustive service discipline.However,if the Timer is shorter than the interarrival time to queue Q1,the server does not wait any more and switches back to queue Q2.At queue Q2,we operate a RTG mechanism T(2),that is,whenever the server reenters queue Q2,an exponential time T(2) is activated.If the server empties the queue before T(2),it immediately leaves for queue Q1.Otherwise,the server completes all the work accumulated up to time T(2) and leaves.Under the assumption of Poisson arrivals,general service and switchover time distributions,we obtain probability generating function(PGF) of the queue lengths at polling instant and mean cycle length and Laplace Stieltjes transform(LST) of the workload.展开更多
文摘Aiming at the specific protocol of RFID technology,a 915MHz CMOS transmitter front-end for OOK modulation is implemented in a 0.18μm CMOS process. The transmitter incorporates a class-E power amplifier （PA）, a modulator, and a control logic unit. The direct-conversion architecture minimizes the required on-and-off-chip components and provides a low-cost and efficient solution. A novel structure is proposed to provide the modulation depth of 100% and 18% ,respectively. The PA presents an output ldB power of 17.6dBm while maintaining a maximum PAE of 35.4%.
文摘In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but somehow in between. This means that, with respect to the on\|line problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi on\|line ones. The authors studied two semi on\|line multiprocessor scheduling problems, in which, the total processing time of all tasks is known in advance, or all processing times lie in a given interval. They proposed approximation algorithms for minimizing the makespan and analyzed their performance guarantee. The algorithms improve the known results for 3 or more processor cases in the literature.
文摘A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.
文摘A novel control system is developed to improve the capabilities of robet hand performing tasks in a variety of environments. A joint impedance control strategy has been successfully implemented in the low level control of a highly integrated robot hand. At flint, a real time controller with DSP＆FPGA-based multilevel control architecture is built. Then a current sensor of the single direct current （DC） link is used to measure and reconstruct the three phase currents, and a stable current signal is measured by optimizing sample instant. The experimental results of the joint impedance control show that the proposed method not only improves the effectiveness of contact environment performance, but also provides compliant interaction of robot hand with a person, which is very important for the development of friendly human robot of the next generation.
基金Project(2006AA04Z228) supported by the National High-Tech Research and Development Program of ChinaProject(PCSIRT) supported by Program for Changjiang Scholars and Innovative Research Team in University
文摘A new impedance controller based on the dynamic surface control-backstepping technique to actualize the anticipant dynamic relationship between the motion of end-effector and the external torques was presented. Comparing with the traditional backstepping method that has ＂explosion of terms＂ problem, the new proposed control system is a combination of the dynamic surface control technique and the backstepping. The dynamic surface control （DSC） technique can resolve the ＂explosion of terms＂ problem that is caused by differential coefficient calculation in the model, and the problem can bring a complexity that will cause the backstepping method hardly to be applied to the practical application, especially to the multi-joint robot. Finally, the validity of the method was proved in the laboratory environment that was set up on the 5-DOF （degree of freedom） flexible joint robot. Tracking errors of DSC-backstepping impedance control that were 2.0 and 1.5 mm are better than those of backstepping impedance control which were 3.5 and 2.5 mm in directions X, Y in free space, respectively. And the anticipant Cartesian impedance behavior and compliant behavior were nchieved successfully as depicted theoretically.
基金Project(hx2013-87)supported by the Qingdao Economic and Technology Development Zone Haier Water-Heater Co.Ltd.,China
文摘In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1400-2600 r/min）, ambient air temperature（2.4-17.8 ℃） and condenser water inlet temperature（30-50℃）. The results show that as engine speed increases from 1400 r/min to 2600 r/min, the total heating capacity and energy consumption increase by about 30% and 89%, respectively; while the heat pump coefficient of performance（COP） and system primary energy ratio（PER） decrease by 44% and 31%, respectively. With the increase of ambient air temperature from 2.4 ℃ to 17.8 ℃, the heat pump COP and system PER increase by 32% and 19%, respectively. Moreover, the heat pump COP and system PER decrease by 27% and 15%, respectively, when the condenser water inlet temperature changes from 30 ℃ to 50 ℃. So, it is obvious that the effect of engine speed on the performance is more significant than the effects of ambient air temperature and condenser water inlet temperature.
文摘The control system of an autonomous underwater vehicle （AUV） is introduced. According to control requirements of the AUV, a simple but practical adaptive PID control method is designed The semi-physical simulation is done to test the feasibility of the control system. The neural network idea and the structure of PID controller are referred to design the adaptive PID controller. An intelligent integral is introduced to improve control precision. Compaed with traditional PID con- trollers, the adaptive PID controller has simple structure, good online adjusting ability, fast convergence and good robustness. The simulation experiments also show that the adaptive PID control system has high precision and fine antijamming ability.
文摘This article presents the development of a robotic controller for technical training, academic teaching, and research. The controller was designed to interact from 1 to 6 DOF （degrees of freedom） serial robotic arms, actuated by brushed DC （direct current） servomotors equipped with incremental encoders. Controller architecture is based on four components： a processor, a reconfigurable FPGA （field-programmable gate array）, measurement I/O hardware and software. Functionality of the robotic controller has been proved by means of the interaction with an SCARA （selective compliance assembly robot arm）. The proposed controller presents the potential to teach technical courses （like robotics, control, electronics and programming） and to implement and validate advanced control algorithms.
基金Supported by the National Natural Science Foundation of China （50875252）
文摘A mathematical model and finite element model for analysis of temperature rise of the hoisting machine brake sys- tem was constructed, limit conditions were defined, and the law of temperature rise of brake shoes during emergent brake course was analyzed and calculated by using finite element software. By analyzing the calculation results, the law of tempera- ture change of surface of brake disk and shoes during the braking process was found. The law of brake shoes surface tempera- ture distribution and the law of temperature change along with thickness of brake shoes at brake time 0.5 s, 1.0 s and 1.5 s was analyzed. A hoisting machine emergent braking test was carried out. Finally, the author concluded that velocity rebound in the process of hoisting machine emergent brake is due to decreased friction coefficient caused by the temperature rise of the brake shoes surface.
文摘The 3D visualization model of slop with structural plane can displayed the characters of structural plane in slop directly, and illustrated the spatial combination. It is a modem and critical question in the field of geotechnical engineering. Based on the peculiarity of the reconnaissance and the research of the visualization by formers, systemized the method fit for building 3D visualization model of slop with structural plane. Write the special program with Visual C^-＋ computer language and illustrated it by OpenGL, the program can displayed and captured the random section plane. The program has a satisfied result by proving with the real projects.
基金supported by the National Key R&D Program of China(Grant No.2017YFA0304000)Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB04010200)+1 种基金the National Natural Science Foundation of China(Grant Nos.91121022,61401441,and61401443)the Science and Technology Commission of Shanghai Municipality(Grant No.16JC1400402)
文摘The rapid development of superconducting nanowire single-photon detectors over the past decade has led to numerous advances in quantum information technology. The record for the best system detection efficiency at an incident photon wavelength of 1550 nm is 93%. This performance was attained from a superconducting nanowire single-photon detector made of amorphous WSi; such detectors are usually operated at sub-Kelvin temperatures. In this study, we first demonstrate superconducting nanowire single-photon detectors made of polycrystalline NbN with system detection efficiency of 90.2% for 1550-nm-wavelength photons at2.1 K, accessible with a compact cryocooler. The system detection efficiency saturated at 92.1% when the temperature was lowered to 1.8 K. We expect the results lighten the practical and high performance superconducting nanowire single-photon detectors to quantum information and other high-end applications.
基金supported by the Joint Training Doctoral Project of China Scholarship CouncilFunds for the Central Universities (Grant No. 3202003905)Scientific Innovation research of College Graduates in Jiangsu Province (Grant No. CXLX12_0080)
文摘The current work is oriented toward the development of a novel biologically inspired bat aerial robot with morphing wings. Based on the flight characteristics data of natural bats(Eptesicus fuscus), a novel four degrees of freedom robotic bat wing was developed to emulate the movements of bat wing. The design, fabrication, programing and wind tunnel experiments of the robot bat wing are described in this paper. Based on this robotic wing, the influence of flap amplitude, wind speed, flight frequency, downstroke ratio and stroke plane angle as well as the contributions of flap, elbow, sweep and wrist motions on the aerodynamic force and mechanical power were studied and analyzed. Results of wind tunnel experiments validated that higher lift would bring greater power consumption, and the flap motion would generate the most force and need more energy expenditure compared with other motions of bat. The experimental results suggest that the flap and fold motions are indispensable to make a robotic bat wing that has a better flight performance. This study provides some implications and a better understanding for the future robotic bat.
基金the National Natural Science Foundation of China(No.10726063)Leading Academic Discipline Program,211 Project for Minzu University of China(the 3rd phaze,No.021211030312)
文摘In this paper,we consider two-queue polling model with a Timer and a Randomly-Timed Gated(RTG) mechanism.At queue Q1,we employ a Timer T(1):whenever the server polls queue Q1 and finds it empty,it activates a Timer.If a customer arrives before the Timer expires,a busy period starts in accordance with exhaustive service discipline.However,if the Timer is shorter than the interarrival time to queue Q1,the server does not wait any more and switches back to queue Q2.At queue Q2,we operate a RTG mechanism T(2),that is,whenever the server reenters queue Q2,an exponential time T(2) is activated.If the server empties the queue before T(2),it immediately leaves for queue Q1.Otherwise,the server completes all the work accumulated up to time T(2) and leaves.Under the assumption of Poisson arrivals,general service and switchover time distributions,we obtain probability generating function(PGF) of the queue lengths at polling instant and mean cycle length and Laplace Stieltjes transform(LST) of the workload.
