Time filter

Source Type

Li R.,Petrochina | Li R.,Beihang University | Feng Q.,Petrochina | Cai M.,Beihang University | And 4 more authors.
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2014

This study presents a multi-sensor data fusion method for solving the problem in surveying long-distance oil-gas pipeline centerline. During in-line inspection (ILI) of long-distance oil-gas pipeline centerline, an inertial measurement unit (IMU) and an odometer are loaded in the ILI. Additionally, a low-frequency transmitter is loaded to activate the global positioning system (GPS) marker placed on the ground which detects the location of ILI. An error model is constructed using the inertia navigation system (INS) and nonlinear dynamic system. Dead reckoning is performed with IMU data and odometer readings. All errors of the INS and odometer are estimated and compensated using extended Kalman filter. Finally, accurate position of pipeline centerline is corrected with data of the GPS marker. Trajectory curves of the same pipeline centerline are compared between ILI surveys at two different times. Results show that the integrated errors of INS-based centerline data are 0.35 m in the horizon and 0.74 m in the height. Accuracy of the ILI is verified by excavating a buried pipeline at one feature point, demonstrating an ILI error <1 m. The proposed method provides an effective means for safe operation of buried pipelines. Source

Sui L.,Beijing Institute of Technology | Zhang J.,Beijing Automatic Control and Equipment Institute | Liu J.,Beijing Institute of Technology | Shi G.,Beijing Institute of Technology
Advanced Materials Research | Year: 2012

First of all, this paper analyzes the piezoresistive accelerometers' research achievements at home and abroad. Then, design, manufacturing and testing method of the accelerometer array is presented. According to the detection requirements of fuze's environmental forces, this paper provides an array accelerometers structure. In this way, each independent chip has 2*2 accelerometers, and every two accelerometers have the same structure sizes. So, the accelerometer array has two different measurement ranges. In order to reduce the influence of cross sensitivity, the accelerometer uses criss-cross beams. Every single accelerometer comprises sensing unit, signal processing circuit and self-test unit. According to the characteristics of processing plant, an entire series of independent processes for micro-mechanical piezoresistive fabrication is designed, and also given the layouts. The accelerometer is fabricated and its sensitivity and self-test performances are tested in this paper, finally this paper gives the reasons which cause test errors. © (2012) Trans Tech Publications, Switzerland. Source

Zhang J.,Shijiazhuang University | Wang J.,Shijiazhuang University | Liu T.,Beijing Automatic Control and Equipment Institute
Advanced Materials Research | Year: 2012

To achieve the numerical control (NC) system based on the standard for the exchange of product model data-numerical control (STEP-NC), the feature concept and feature recognition method of STEP-NC is proposed. The meaning of feature in STEP-NC, while the three classification methods of STEP-NC feature were also presented. The expression methods of STEP-NC feature were analyzed in details. Furthermore, the feature recognition methods based on above the analyse were described. Finally, we simulate several machining features on STEP-NC milling simulation system. The simulation results demonstrate that the feature recognition method is correct and feasible. © (2012) Trans Tech Publications, Switzerland. Source

Yi G.-X.,Harbin Institute of Technology | Xie Y.-G.,Harbin Institute of Technology | Li Q.-H.,Harbin Institute of Technology | Wang C.-H.,Harbin Institute of Technology | And 2 more authors.
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2012

A spaceborne attitude measurement system (SAMS) based on Hemispherical Resonator Gyro (HRG) and star sensor is developed in this paper in order to meet the requirements of long life satellites, such as high precision, high reliability, low power consumption and light weight. In view of the characteristics of domestic HRG and accelerator, a new structure configuration is designed and tested. With quaternion-based attitude algorithm, the Kalman filter is introduced to integrate the measurements of AMS with star sensor. The tests in laboratory environment shows that the static attitude precision arrives 13.9″(peak), and the dynamic posture precision reaches 15.4″(peak), hence the engineering prototype of SAMS meets the requirements of high precision satellites. Source

Zhou B.-C.,Nanjing Southeast University | Cheng X.-H.,Nanjing Southeast University | Liu D.-J.,Beijing Automatic Control and Equipment Institute
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2010

In order to solve the problem in rapid and accurate transfer alignment of the shipboard weapon strapdown inertial navigation system (SINS), the velocity and attitude matching method is simplified into a velocity and head matching method, and the model of transfer alignment is established. From this, a new observable degree analysis method based on Hermite matrix spectral decomposition theory is presented to analyze the system states. The method only requires spectral decomposing for Hermite matrix whose order is the same as the dimension of observations. Finally, the system states of three matching methods (velocity matching, velocity and attitude matching, velocity and head matching) are analyzed using the observable degree analysis method. The simulation result shows that the observable degree analysis method is correct and effective, and the transfer alignment accuracy is within 4? in 10 s by the velocity and head matching method, which rapidly and accurately realizes SINS transfer alignment. Source

Discover hidden collaborations