Abstract:Outdoor baseline is the special length standard in the field of surveying and mapping, it can be used to verify the addition and multiplication constants of the total station and other photoelectric rangefinders. In order to ensure the authenticity, accuracy and reliability of verification results, conducting outdoor baseline traceability periodically is essential. At present, direct measurement by 24 m invar tape or high precision electro-optical measurement is mainly used to achieve the traceability of outdoor baseline in China, a large number of experimental facts have shown that there are still system errors between the quantity transfer of baselines in China and abroad. With the rapid development of China′s manufacturing industry and the proposal of “made in China 2025”, the traditional traceability technology of outdoor baseline is difficult to meet the increasingly high precision requirements, and it is urgent to achieve the outdoor baseline precision ranging. Combined with the current research situation at home and abroad, optical interferometry by Vaisala interference comparator, direct measurement by 24 m invar tape and high precision electro-optical measurement are summarized，the advantages and disadvantages of the three methods are deeply analyzed. Last but not least, some thoughts and suggestions are put forward for the future outdoor baseline field construction in China.

Abstract:Electromagnetic acoustic transducer（EMAT）sensors are widely concerned because they do not need couplers and can be used in high-temperature environments. However, there are problems such as low energy conversion efficiency, small amplitude of ultrasonic echo signal, and easy to be disturbed by noise, which need to be further studied. According to the working mechanism of the EMAT, through analyzing the characteristics of the echo signal of ultrasonic Lamb determines the index of receiving circuit, design and optimize the impedance matching circuit, preamplifier circuit and low-pass filter circuit, and design the digital bandpass filter for further signal processing. Firstly, the preamplifier circuit is simulated to make it capable of receiving small signals. Then a three-stage MFB low pass filter circuit is adopted to eliminate the spatial coupling noise. The EMAT flaw detection test of aluminum plate was made and built by circuit hardware. The results show that the designed receiver circuit can detect lamb wave well, which provides a foundation for the development of the testing system.

Abstract:The on-line monitoring device of transmission line in Xinjiang Province cannot work normally in the extremely cold environment, which brings some difficulties to the operation and maintenance of transmission line. In this paper, the implementation scheme of power tapping from OPGW was put forward. Based on EMTP simulation platform, 500 kV ac transmission line model was established, which simulated the induced voltage and current, and the dual insulation mode is proposed. The results prove that the induced voltage and current of ground wire are positively correlated with the spacing and load power, and are basically unaffected by the soil resistivity; when the span is 300 m and the load power is 500 MW, the output power of the ground wire energy-collecting device is 137.8 W, fully meeting the power supply demand of on-line monitoring device in the transmission line; under the condition of long-term extremely cold temperature -45 ℃, by using nano porous silica insulation membrane and infrared radiation heating, it still can ensure ideal temperature conditions,which is not less than -30 ℃; after the insulation measures are adopted for the power supply, the mean rate of no failure in online monitoring device is increased from 85.9 to 99.6%, and the reliability is significantly increased. The research results provide a design idea of stable power supply for on-line monitoring devices in extremely cold regions.

Abstract:In order to solve the problem that the surplus torque′s strong interference to the electric load simulator and affects the tracking accuracy, the fuzzy PID control method based on particle swarm optimization is applied to the design of motor controller. Firstly, the mathematical model of the electric loading system is established based on the analysis of the structure and working principle of the loading motor, and feedforward compensation is deduced by the principle of structural invariability; Secondly, because of conventional PID controller cannot deal with the complex nonlinear environment by changing parameters, and the fuzzy PID quantization factor scale factor is difficult to adjust by experience, a compound control strategy based on fuzzy PID and particle swarm optimization algorithm is proposed. Finally, the simulation result shows that the proposed control strategy is superior to the conventional fuzzy PID controller.

Abstract:Due to the high level penetration of several types of distributed energy source, storage system needs to be added in modern power system to suppress power flow fluctuation. In order to realize high efficiency bidirectional power conversion under the circumstance of wide input and output voltage range in energy storage system, a bidirectional buck-boost DC/DC converter based on multi-mode control is studied in this paper. When the input voltage exceeds the output voltage above a certain threshold, valley current mode control is employed and the converter operates as buck region. When the output voltage exceeds the input voltage above a certain threshold, peak current mode control is used and the converter operates as boost region. Furthermore, when the intput voltage is similar to the output voltage, phase-shift mode control is adopted to obtain seamless transition and the converter operates in a manner of buck and boost combination. In order to realize high accurary output and fast dynamics, Type II compensator is employed. By the approach of small portion overlaping between Buck region and Boost region, the discontinuity happened at region transition in traditional Buck-Boost converter is eliminated. 97.5% peak efficiency is achieved in the 1 kW hardware prototype and the transition between Buck region and Boost region is smooth.

Abstract:Wireless power transmission (WPT) based on the magnetically-coupled resonant is a hot topic in the research and development in modern electrical technology. It is the most likely to be a technology to provide solutions for wireless power supply of electrical equipment, such as household appliances, various consumer electronic products, smart wearable devices and embedded medical devices. The WPT is a flexible access and transmission for real-time power supply. In order to get rid of the shackles of the traditional power cord, the limitation of the space and distance of the power supply mode is solved. Using coupled-mode theory, the two identical helical coils are built with the height of 20 cm, the diameter of 60 cm and the number of turns of 5.25. Both coils are made of hollow copper wire. The expected resonant frequency given is 7.65 MHz, which is about 4.5% off from the measured resonance at 8 MHz. Control the class E power amplifier(PA) gate with an 8 MHz square wave signal, The effects of the nonlinear and linear shut capacitance have been considered in the drain of PA, it is important to predict the performance when an external capacitor is necessary to add for the optimal Class-E mode. Impedance matching is designed to maximum the power transfer from the drain of PA to the transmission coil. The system achieves the maximum transmission distance of 6 meters on the theoretical basis of the transmitting coil of diameter of 60 cm. According to experimental analysis, the system has a great improvement in transmission distance.

Abstract:In order to improve the real-time control ability of biped robot, a real-time obstacle avoidance position control method for biped robot based on reinforcement learning is proposed. Taking the stability of biped walking as the control objective function, the real-time path dynamics model of biped robot is constructed. The acceleration and inertia moment of the robot′s centroid motion are taken as the controlled object. The effective collision sub-model is used to plan the real-time obstacle avoidance path of biped robot, and the collision sub-model and swing sub-model are combined to adjust the error correction parameters of biped robot. The fuzzy reinforcement learning tracking method is used to control the error gain of biped robot, and the real time obstacle avoidance position control of biped robot is realized. The simulation results show that the proposed method can avoid obstacles in real time and improve the adaptive control ability of biped robot.

Abstract:Wireless power transmission technology is the key technology that enables special robots to achieve lightweight sustainable work. The magnetic coupling resonant wireless charging, must consider the impact of metal obstacles on the transmission system. The metal eddy current effect is equivalent to mutual inductance coupling circuit, and the transmission system is modeled by coupling circuit theory. The transmission equation of voltage gain coefficient and the expression of energy loss of metal obstacles to transmission system are derived. With the change of coupling coefficient, the transmission system still has frequency splitting, critical coupling, over-coupling and under-coupling. Given the parameters of the transmission system, the critical coupling coefficient Kc=1.54×10-4. When there are metal obstacles, K′c=1.09×10-2. which lead to the reduction of voltage gain, the shift of resonance frequency, the increase of coupling coefficient and the decrease of coupling performance in wireless transmission system. The change of output voltage in the presence of metal barrier is obtained by simulation.

Abstract:Take the high-voltage high-power chip TO-3 package structure with operating voltage of 70V and output current of 9A as an example, the three-dimensional package model is first established based on the thermal analysis software Flo THERM, and the thermal characteristics of the package model is simulated and analyzed. Secondly, comparative analysis is carried out for the presence/absence of substrates, different substrate materials, and different package materials. Finally, the temperature of the package is studied according to the thickness of the bonding layer, the power and the thickness of the substrate, and a package with optimized heat dissipation is obtained. The simulation results show that The higher the thermal conductivity of the substrate material and the package casing, the better the heat dissipation effect. As the thickness of the bonding layer and the power of the chip increase, the temperature of the chip gradually increases. As the thickness of the substrate increases, the temperature of the chip decreases. The heat dissipation effect is optimal when the substrate material is copper, the package casing is BeO, and the bonding layer is AuSn20.

Abstract:The engine mount system is an important part of the vehicle, Play the role of supporting engine, blocking vibration and improving ride comfort in the process of driving This paper studies the relationship between the stiffness of the suspension element and the inherent characteristics of the suspension system by modeling and simulation of the automobile engine. In Adams software, a three-dimensional model of the engine suspension system is established, simulation analysis is conducted, and the intrinsic frequency and vibration modal energy decoupling distribution of the suspension system is obtained in the Vibration vibration module. The analysis shows that the vibration isolation effect is poor. With the stiffness of suspended rubber pad as the optimized parameter, a new energy decoupling distribution is obtained, and the decoupling rate in the main vibration direction reaches more than 80%. Compared with the initial data, the decoupling degree is greatly improved, which shows that the optimized data has obvious effect on the vibration isolation of the engine, and verifies the feasibility of the optimized design method.

Abstract:A new black and white color selection system based on ZYNQ-7000 series fully-programmable SoC is designed to solve the problem of slow detection speed and low integration of traditional black and white color selection system. Using hardware and software co-design methods, firstly linear CCD image acquisition, grayscale correction, threshold comparison and valve output are implemented on the PL side. Then using the AXI interface to cache the compensated grayscale value, valve output signal, and setup parameters to the DDR3 SDRAM memory, and finally The PS side is ported to an embedded Linux operating system for real-time display and human-computer interaction. The experimental results show that the system can effectively measure the eigenvalue parameters of the materials with screening, and carry out the selection, the operation is stable and reliable, and meets the requirements of industrial applications.

Abstract:In order to improve the working efficiency of the parallel H-bridge active filter, when the power supply voltage is distorted, a more accurate harmonic compensation current is calculated in a shorter time, and an accurate compensation command is provided for the deadbeat control. A control strategy combining adaptive harmonic detection algorithm with carrier phase shift sinusoidal pulse width modulation (CPS-SPWM). Firstly, the reference compensation current is calculated quickly and accurately by the adaptive harmonic detection algorithm. Then, the bridge voltage stability is realized by the outer loop voltage PI control, and the internal loop equalization proportional control is used to realize the same capacitor voltage of the sub-module on the bridge arm. CPS-SPWM provides a more accurate modulated wave signal for active filters. Through simulation experiments, it is verified that the control strategy has higher stability and accuracy than traditional methods.

Abstract:Large-scale MIMO systems need multiple antennas in a limited space, which will inevitably introduce coupling and will affect the performance of MIMO systems. This paper studies the Water-Pouring capacity of MIMO systems based on S-parameters. Through the S-parameter network model, the Water-Pouring Principle is introduced on the power distribution of the transmission end, and the capacity closure formula under different matching conditions is derived. The capacity under different matching conditions of the receiver is simulated by Matlab, including: no coupling, self-impedance matching, optimal matching. The results show that the introduction of the Water-Pouring Principle maximizes the power of the transmission end and the system performance is greatly improved under the condition of optimal conjugate matching at the receiving end.

Abstract:The brushless DC motor (BLDCM) has the outstanding shortcomings of torque ripple. A new hybrid control strategy based on DC link voltage control and fuzzy PID controller is proposed to suppress the torque pulse of the brushless DC motor. The circuit topology contains power. Factor corrected buck converter and inverter. The buck converter reduces commutation torque ripple by controlling the DC circuit voltage, and an inverter using a fuzzy PID controller and pulse width modulation (PWM) technology provides the appropriate current in the conduction region. The Buck converter reduces the commutation torque ripple by controlling the DC link voltage. The inverter uses the fuzzy PID and PWM technology to provide the current in the conduction region. This method can eliminate the torque ripple in the conduction region and weaken the torque ripple in the commutation region. The simulation results show that the strategy has a power factor correction function, which can effectively suppress torque ripple. Improve the robustness of motor operation.

Abstract:Aiming at the problem of energy hole in linear wireless sensor networks, a non-uniform deployment scheme of energy consumption equilibrium in linear wireless sensor network is proposed. The scheme proves that in addition to the sub-monitoring area furthest from the Sink node, the remaining sub-monitoring area can achieve network energy consumption balance when the number of sensor nodes in it increases equally from far to near, and a sufficient number of relay sensor nodes need to be randomly deployed to forward data. The simulation results show that the proposed scheme can effectively solve the problem of energy hole, make the linear wireless sensor network can achieve the goal of balanced energy consumption, and greatly extend the life of the network, which is of great significance for improving the performance of the actual linear wireless sensor network.

Abstract:DeepCS, a kind of coflow scheduling algorithm, is obtained through reconstruction. The coflow resource view is regarded as the image to be processed later, and the optimal scheduling effect of coflow is achieved according to the previous learning strategy.The feature parameters extracted by DNN need not be designed by manual method, and can be realized by separate learning process.The training input includes various network and task situations, with the motion probability distribution as the output, and EPiSOdE as the unit to carry out the training process.The simulation results are as follows: when the coflow reaches a larger rate, all algorithms will need longer coflow completion time. At this point, the flow time and working pressure of the scheduling algorithm will increase, thus forming a longer average coflow completion time.Under the lower coflow arrival rate, VARYS and DeepCS have similar performance, both of which are better than PFABRiC, and DeepCS has the fastest performance improvement.

Abstract:The near-drilling tool can effectively overcome the shortcomings of the conventional measurement while drilling system, which is very suitable for use in complex formations or thin reservoirs, and has the advantages of convenient field assembly and low operating cost. Near-bit azimuth gamma measurement system is the core of its geological steering control. In this paper, two important modules of near-bit azimuth gamma ray measurement system are introduced in detail: sector measurement module and gamma counting processing module. Field experiments show that the system can quickly indicate the direction of the tool crossing the horizon, meet the requirements of field operation, and has a certain market value.

Abstract:Triangular rasterization is an indispensable part of the graphics processor. In order to improve the efficiency of triangle rasterization and reduce the hardware design cost of GPU. This paper combines the characteristics of Bresenham algorithm and adder-based divider to propose an improved Bresenham algorithm. And the algorithm is applied to triangle rasterization. The algorithm is verified by software simulation, and tested in the hardware test platform of FPGA. The results show that the improved Bresenham algorithm can achieve triangle rasterization better and consumes less hardware resources than the traditional Bresenham algorithm, which reduces the unit cost of GPU hardware design and improves the efficiency of triangle rasterization in GPU.

Abstract:Thermal control system is an important subsystem of FENGYUN meteorological satellites, which directly affects the work of the other subsystems and the satellite life. Therefore, long-term in-orbit monitoring, fault detection and fault diagnosis for the system have a major practical indicating significance. Based on detailed analysis of the principle, function and composition of FENGYUN meteorological satellites thermal control system, the paper makes a systematic study of its ground health management mechanism and technology, and designs corresponding comprehensive application platform. With telemetry data as input, the scenario of the failure is established, realized the monitoring and health management of the FY3D thermal control system, having the function of correlation analysis and visual expression of temperature fluctuation events caused by state changes of satellite platform and payloads. It can provide effective early warning and assistant guarantee for the satellite security, and has the value of popularization.

Abstract:Image measuring instrument has been widely used in the field of industrial measurement, especially in the measurement of precision planar parts. When measuring a full set of parts, the traditional image measuring instrument needs to manually control the platform movement to reach the measuring position, which leads to prolonged measurement time and low efficiency. In this paper, a universal image measurement instrument is used as the experimental platform. The feature is moved from any position of the platform to a small field of vision through a large field of vision in the way of continuous use of the camera of large and small field of vision, which is corrected by using the small field of vision to achieve precise positioning and optimize the measurement time. The experimental results show that this method can effectively move any feature point within the range of large field of vision to the center of small field of image. Finally, an automatic positioning method for thin sheet parts of the image measuring instrument is proposed. The experiment proves that this method can effectively reduce the measurement time and the movement error of feature points is within 0.05mm.

Abstract:According to the characteristics of the variable motion trajectory and postures during the floating buoy operation that affect the reliability of the sensor, the floating buoy attitude measurement system based on three-axis MEMS gyroscope, accelerometer and magnetoresistive sensor is designed. This paper presents the hardware structure and software algorithm flow of the design system. It use, quaternary method and PI regulation algorithm to perform attitude algorithm and data fusion. The systematic error is corrected by ellipsoid fitting and threshold filtering for error compensation method. Experimental results show that the proposed design is more effective in the measurement of motion attitude which has small static error and good dynamic anti-interference performance to meet the basic needs of attitude measurement of ocean drift buoys.

Abstract:In order to improve the stability of the terminal position and pose adjustment, the software robot is disturbed by steady-state error, which leads to the problem of independent control of the stiffness of the software robot. An independent stiffness control method for soft robot based on end circle calibration is proposed. The rigid body mechanics decomposition method is used to construct the dynamic analysis model of software robot, and the strict feedback control method is used to control the terminal position and pose memory of software robot. The scale integral controller is used to calibrate the end circle of the software robot, and the inverse kinematics model is used to adjust the rigid body independence of the software robot. In the joint space, the end position and attitude feedback correction of the robot is realized by adjusting the deviation correction and the adaptive stabilization of the programming trajectory, and the optimal control of the software robot is realized. The simulation results show that the algorithm has good steady-state stability and strong deviation correction ability for independent stiffness control of software robots.

Abstract:In order to measure and study the contact impedance of the contact interface between the central rail and the electromagnetic launching system, a low impedance measurement system at low frequency is developed. The system measures the vector voltage at both ends of the impedance to be measured and the standard impedance separately by impedance transformation method. The real and imaginary parts of the vector voltage are separated by phase sensitive detection method based on free axis. The magnitude of the impedance to be measured is calculated according to the relationship between the standard impedance voltage and the impedance voltage to be measured. The system uses STM32 controller as signal generator and controller, adopts Kelvin four-wire method to reduce the influence of lead resistance and contact resistance, and uses software compensation method to reduce measurement error. The measurement results show that the measuring system can work normally within 10 kHz and has high accuracy in measuring resistance within 100 Ω.

Abstract:As an important industrial site of natural gas transmission and distribution system, it has become particularly important for LNG gas station to ensure safe operation and reduce potential safety hazards. The article takes the actual project of a liquefied gas station as the background. In order to improve the safety performance of small and medium-sized LNG gas station control system, a cost-effective intelligent monitoring system was designed. It implements a human-computer interaction interface and real-time data acquisition monitoring alarming and interlocking functions in order to meet the production monitoring needs of LNG gas stations based on FIX configuration software and SHCAN fieldbus. The system test results show that the real-time display of the completed data can be refreshed within 300 ms, several years’historical data can be recorded and it can realize alarm management. The operation results that the monitoring system designed by this project is correct and effective.

Abstract:The bus-based distributed structure has been applied to the field of drones because of its simple structure, easy expansion, and maintainability. The research group takes unmanned helicopter as the research object, and carries on the technical upgrade on the basis of the original centralized flight control system. A design scheme of distributed flight control system based on CAN bus is proposed. It describes the overall design scheme, hardware design, communication mechanism, software development and implementation of distributed system based on CAN bus, and carries out semi-physical simulation verification. The test results show that the actual bandwidth occupied by CAN bus is 10.5%, and there is no frame loss. The synchronization accuracy of communication reference clock is less than 150 μs, which can fully meet the requirements of flight control system. Through the whole process of flight semiphysical simulation, it is proved that the distributed flight control system based on CAN bus can meet the real-time, reliability and other control requirements of unmanned helicopter flight control system, and the design meets the engineering requirements.

Abstract:In recent years, convolutional neural networks have done a great job in many machine vision tasks. However, existing software implementations are not well implemented in portable devices. A convolutional neural network system based on Xilinx all-programmable SoC is designed to accelerate the convolutional operation in parallel, which only need few design resource and implement fast detection system. The system uses multi-stage pipeline technology and input data reuse to improve calculation efficiency. The hardware part completes convolutional network calculation, and the software part finish the image preprocessing and post-image detection preprocessing, thereby improving operation efficiency. The system can implements the convolution operation with different size, mean pooling operation and the non-maximum suppression algorithm, which achieves accurate positioning of multiple faces in the picture. The experimental results show that the average calculation rate of the system is 0.19 Gops/s at the operating frequency of 100 MHz，and the power consumption is only 4.07% of the general purpose CPU.

Abstract:In order to satisfy the requirements of real-time, low-power and miniaturization for dynamic target recognition and tracking system, a system based on FPGA is designed, which is supplemented by OV7670 video acquisition module and VGA interface displayer. The image is captured, processed and marked with a rectangle. Consequently, the dynamic recognition, tracking and display are realized. Among them, the image processing part is completed by FPGA, including cache, gray processing, improved bit operation median filtering, background and foreground separation, inter-frame difference method and background difference method compromising. It making full use of the merits of high-speed and parallel processing ability of FPGA, high-speed RAM on-chip, large capacity of off-chip SDRAM to achieve the processing and storage of video data. At the same time, the system has strong anti-interference, compact, flexible, low power consumption, versatility and scalability, which is suitable for industrial areas, but also suitable for home use.

Abstract:With the continuous development of wireless communication technology, the research of Nakagami-m fading channel simulation model has been a hot spot. In order to get the best simulation model of fading channel, three simulation methods of Nakagami-m (m<1) fading channel are introduced, which are based on Beta function simulation method, approximate inverse cumulative distribution function simulation method and sinusoidal summation simulation method. The simulation maps of amplitude, phase and envelope autocorrelation function of the three methods are obtained by Matlab simulation software, and the results are compared and analyzed. The simulation method based on approximate inverse cumulative distribution function transformation is the best, followed by the Beta function simulation method, and the sinusoidal summation method is the most unsatisfactory.

Abstract:With the development of urban infrastructure construction, the current management of urban manhole cover is widespread, it is difficult to achieve unified management, and the problem of damage and theft of the manhole cover cannot be found in time. This paper proposes an intelligent manhole cover communication alarm system based on narrowband Internet of Things (NB-IOT). The sensor uses real-time monitoring of manhole cover information. The NB-IOT terminal module sends status information to the base station, and the base station connects with the core network of NB-IOT. The status data is sent to the cloud platform, and the background management system can obtain the fault information of the manhole cover in real time. Through a large number of experimental tests, the intelligent manhole cover communication mechanism proposed in this paper is to meet the requirements of low power consumption and can accurately detect the fault information of the manhole cover.