The accuracy of the HB2 standard model attitude measurement has an important impact on the hypersonic wind tunnel data assessment.The limited size of the model and the existence of external vibrations make it challeng...The accuracy of the HB2 standard model attitude measurement has an important impact on the hypersonic wind tunnel data assessment.The limited size of the model and the existence of external vibrations make it challenging to obtain real-time reliable attitude measurement.To reduce the influence of attitude errors on test results,this paper proposes a Quaternion Nonlinear Complementary Filter(QNCF)attitude determination algorithm based on Microelectromechanical Inertial Measurement Unit(MEMS-IMU).Firstly,the threshold-based PI control strategy is adopted to eliminate noise effect according to the Acceleration Magnitude Detector(AMD).Then,the flexible quaternion method is updated to carry out attitude estimation which is operational and easy to be embedded in the Field Programmable Gate Array(FPGA).Finally,a high-precision three-axis turntable test and a hypersonic wind tunnel test are performed.The results show that the pitchroll attitude errors are within 0.05°and 0.08°in the high-precision three-axis turntable test in a calculation time of 100 s respectively,and the attitude error is within 0.3°after the elastic angle correction in the hypersonic wind tunnel test.The proposed method can provide accurate real-time attitude reference for the analysis of the actual movement of the model,exhibiting certain engineering application value with robustness and simplicity.展开更多
The Global Positioning System(GPS)offers the interferometer for attitude determination by processing the carrier phase observables.By using carrier phase observables,the relative positioning is obtained in centimeter ...The Global Positioning System(GPS)offers the interferometer for attitude determination by processing the carrier phase observables.By using carrier phase observables,the relative positioning is obtained in centimeter level.GPS interferometry has been firstly used in precise static relative positioning,and thereafter in kinematic positioning.The carrier phase differential GPS based on interferometer principles can solve for the antenna baseline vector,defined as the vector between the antenna designated master and one of the slave antennas,connected to a rigid body.Determining the unknown baseline vectors between the antennas sits at the heart of GPS-based attitude determination.The conventional solution of the baseline vectors based on least-squares approach is inherently noisy,which results in the noisy attitude solutions.In this article,the complementary Kalman filter(CKF)is employed for solving the baseline vector in the attitude determination mechanism to improve the performance,where the receiver-satellite double differenced observable was utilized as the measurement.By using the carrier phase observables,the relative positioning is obtained in centimeter level.Employing the CKF provides several advantages,such as accuracy improvement,reliability enhancement,and real-time assurance.Simulation results based on the conventional method where the least-squares approach is involved,and the proposed method where the CKF is involved are compared and discussed.展开更多
This paper considers the blind source separation in under-determined case,when there are more sources than sensors.So many algorithms based on sparse in some signal representation domain,mostly in Time-Frequency(T-F) ...This paper considers the blind source separation in under-determined case,when there are more sources than sensors.So many algorithms based on sparse in some signal representation domain,mostly in Time-Frequency(T-F) domain,are proposed in recent years.However,constrained by window effects and T-F resolution,these algorithms cannot have good performance in many cases.Considering most of signals in real world are band-limited signals,a new method based on sub-band division is proposed in this paper.Sensing signals are divided into different sub-bands by complementary filter firstly.Then,classical Independent Component Analysis(ICA) algorithms are applied in each sub-band.Next,based on each sub-band's estimation of mixing matrix,the mixing matrix is estimated with cluster analysis algorithms.After that,the sub-band signals are recovered using the estimation mixing matrix,and then,the resource signals are reconstructed by combining the related sub-band signals together.This method can recover the source signals if active sources at any sub-band do not exceed that of sensors.This is also a well mixing matrix estimating algorithm.Finally,computer simulation confirms the validity and good separation performance of this method.展开更多
Matrix factorization （MF） has been proved to be a very effective technique for collaborative filtering （ CF）, and hence has been widely adopted in today＇s recommender systems, Yet due to its lack of consideration...Matrix factorization （MF） has been proved to be a very effective technique for collaborative filtering （ CF）, and hence has been widely adopted in today＇s recommender systems, Yet due to its lack of consideration of the users＇ and items＇ local structures, the recommendation accuracy is not fully satisfied. By taking the trusts among users＇ and between items＇ effect on rating information into consideration, trust-aware recommendation systems （TARS） made a relatively good performance. In this paper, a method of incorporating trust into MF was proposed by building user-based and item-based implicit trust network under different contexts and implementing two implicit trust-based context-aware MF （]TMF） models. Experimental results proved the effectiveness of the methods.展开更多
In this paper, a design of very compact microstrip bandstop filters based on complementary split ring resonators (CSRRs) is proposed. Two techniques of metamaterial miniaturization are used to optimize the physical an...In this paper, a design of very compact microstrip bandstop filters based on complementary split ring resonators (CSRRs) is proposed. Two techniques of metamaterial miniaturization are used to optimize the physical and electrical size of the CSRR. The bandstop filter is produced by an array of miniaturized loaded CSRRs etched on the center line of a microstrip. The size of the proposed filter, is as small as 0.58 cm2, and its electrical length is very small with only 0.08 λ0), compared to a conventional bandstop filter, a miniaturization of a factor 5 while the bandstop performance is maintained. A very good agreement obtained between the measurement and the simulation results.展开更多
Quatemions complementary filter attitude algorithm was conducted on the unmanned aerial vehicle （UAV） platform. This introduces traditional attitude algorithm and attitude quaternion complementary filter algorithm d...Quatemions complementary filter attitude algorithm was conducted on the unmanned aerial vehicle （UAV） platform. This introduces traditional attitude algorithm and attitude quaternion complementary filter algorithm difference, and the attitude quatemion complementary filter algorithm realization are introduced in details展开更多
以TC264单片机为控制核心设计了能实现高速寻迹与动态稳定的动量轮平衡单车控制系统:运用陀螺仪作为姿态传感器测算车体位置信息并确定小车平衡的机械零点,通过卡尔曼滤波、一阶互补滤波等算法处理陀螺仪读取的车体姿态信息,将滤波后的...以TC264单片机为控制核心设计了能实现高速寻迹与动态稳定的动量轮平衡单车控制系统:运用陀螺仪作为姿态传感器测算车体位置信息并确定小车平衡的机械零点,通过卡尔曼滤波、一阶互补滤波等算法处理陀螺仪读取的车体姿态信息,将滤波后的信息分别输入串级PID(Proportional Integral Differential,比例、积分、微分)控制器的角速度内环与角度内环,使用编码器作为前进速度传感器构建前进速度环,使用摄像头作为循迹传感器构建转向环,通过控制动量轮实现车体控制。测试结果表明,该系统可以实现车体在静止状态及循迹状态下的直立平衡,由自平衡控制、前进速度控制、转向控制共同实现单车系统的循迹平衡控制,表现出较好的控制效果。该研究可为相似的控制工程提供参考。展开更多
文摘The accuracy of the HB2 standard model attitude measurement has an important impact on the hypersonic wind tunnel data assessment.The limited size of the model and the existence of external vibrations make it challenging to obtain real-time reliable attitude measurement.To reduce the influence of attitude errors on test results,this paper proposes a Quaternion Nonlinear Complementary Filter(QNCF)attitude determination algorithm based on Microelectromechanical Inertial Measurement Unit(MEMS-IMU).Firstly,the threshold-based PI control strategy is adopted to eliminate noise effect according to the Acceleration Magnitude Detector(AMD).Then,the flexible quaternion method is updated to carry out attitude estimation which is operational and easy to be embedded in the Field Programmable Gate Array(FPGA).Finally,a high-precision three-axis turntable test and a hypersonic wind tunnel test are performed.The results show that the pitchroll attitude errors are within 0.05°and 0.08°in the high-precision three-axis turntable test in a calculation time of 100 s respectively,and the attitude error is within 0.3°after the elastic angle correction in the hypersonic wind tunnel test.The proposed method can provide accurate real-time attitude reference for the analysis of the actual movement of the model,exhibiting certain engineering application value with robustness and simplicity.
基金This work has been partially supported by the Ministry of Science and Technology of the Republic of China[Grant Number:MOST 108-2221-E-019-013].
文摘The Global Positioning System(GPS)offers the interferometer for attitude determination by processing the carrier phase observables.By using carrier phase observables,the relative positioning is obtained in centimeter level.GPS interferometry has been firstly used in precise static relative positioning,and thereafter in kinematic positioning.The carrier phase differential GPS based on interferometer principles can solve for the antenna baseline vector,defined as the vector between the antenna designated master and one of the slave antennas,connected to a rigid body.Determining the unknown baseline vectors between the antennas sits at the heart of GPS-based attitude determination.The conventional solution of the baseline vectors based on least-squares approach is inherently noisy,which results in the noisy attitude solutions.In this article,the complementary Kalman filter(CKF)is employed for solving the baseline vector in the attitude determination mechanism to improve the performance,where the receiver-satellite double differenced observable was utilized as the measurement.By using the carrier phase observables,the relative positioning is obtained in centimeter level.Employing the CKF provides several advantages,such as accuracy improvement,reliability enhancement,and real-time assurance.Simulation results based on the conventional method where the least-squares approach is involved,and the proposed method where the CKF is involved are compared and discussed.
基金Sponsored by the Provincial or Ministry Level Pre-research(Grant No. 914A220309090C0201)
文摘This paper considers the blind source separation in under-determined case,when there are more sources than sensors.So many algorithms based on sparse in some signal representation domain,mostly in Time-Frequency(T-F) domain,are proposed in recent years.However,constrained by window effects and T-F resolution,these algorithms cannot have good performance in many cases.Considering most of signals in real world are band-limited signals,a new method based on sub-band division is proposed in this paper.Sensing signals are divided into different sub-bands by complementary filter firstly.Then,classical Independent Component Analysis(ICA) algorithms are applied in each sub-band.Next,based on each sub-band's estimation of mixing matrix,the mixing matrix is estimated with cluster analysis algorithms.After that,the sub-band signals are recovered using the estimation mixing matrix,and then,the resource signals are reconstructed by combining the related sub-band signals together.This method can recover the source signals if active sources at any sub-band do not exceed that of sensors.This is also a well mixing matrix estimating algorithm.Finally,computer simulation confirms the validity and good separation performance of this method.
文摘Matrix factorization （MF） has been proved to be a very effective technique for collaborative filtering （ CF）, and hence has been widely adopted in today＇s recommender systems, Yet due to its lack of consideration of the users＇ and items＇ local structures, the recommendation accuracy is not fully satisfied. By taking the trusts among users＇ and between items＇ effect on rating information into consideration, trust-aware recommendation systems （TARS） made a relatively good performance. In this paper, a method of incorporating trust into MF was proposed by building user-based and item-based implicit trust network under different contexts and implementing two implicit trust-based context-aware MF （]TMF） models. Experimental results proved the effectiveness of the methods.
文摘In this paper, a design of very compact microstrip bandstop filters based on complementary split ring resonators (CSRRs) is proposed. Two techniques of metamaterial miniaturization are used to optimize the physical and electrical size of the CSRR. The bandstop filter is produced by an array of miniaturized loaded CSRRs etched on the center line of a microstrip. The size of the proposed filter, is as small as 0.58 cm2, and its electrical length is very small with only 0.08 λ0), compared to a conventional bandstop filter, a miniaturization of a factor 5 while the bandstop performance is maintained. A very good agreement obtained between the measurement and the simulation results.
基金supported by the National Science and Technology(2015BAK06B04)
文摘Quatemions complementary filter attitude algorithm was conducted on the unmanned aerial vehicle （UAV） platform. This introduces traditional attitude algorithm and attitude quaternion complementary filter algorithm difference, and the attitude quatemion complementary filter algorithm realization are introduced in details
文摘以TC264单片机为控制核心设计了能实现高速寻迹与动态稳定的动量轮平衡单车控制系统:运用陀螺仪作为姿态传感器测算车体位置信息并确定小车平衡的机械零点,通过卡尔曼滤波、一阶互补滤波等算法处理陀螺仪读取的车体姿态信息,将滤波后的信息分别输入串级PID(Proportional Integral Differential,比例、积分、微分)控制器的角速度内环与角度内环,使用编码器作为前进速度传感器构建前进速度环,使用摄像头作为循迹传感器构建转向环,通过控制动量轮实现车体控制。测试结果表明,该系统可以实现车体在静止状态及循迹状态下的直立平衡,由自平衡控制、前进速度控制、转向控制共同实现单车系统的循迹平衡控制,表现出较好的控制效果。该研究可为相似的控制工程提供参考。
