Volume 46,2024 Issue 4

航空宇航科学与技术

• Review of key technologies for autonomous homing of parafoil systems

  Review of key technologies for autonomous homing of parafoil systems

  SUN Qinglin; YANG Jinshan; SUN Hao; CHEN Zengqiang
  Abstract:In order to explore the key technologies of parafoil systems, including modeling, trajectory planning, and trajectory tracking control, to support their autonomous homing in wide application prospects in large-scale equipment airdrop replenishment, carrier rocket booster recovery, and natural disaster rescue applications. Through research on the development of parafoil systems both domestically and internationally, a comparative analysis and summary of the basic principles, commonly used methods, and cutting-edge technologies of the three key technologies were conducted, with a focus on the flexible modeling technology of parafoil systems in complex environments, trajectory planning technology in obstacle spaces, and trajectory tracking technology based on intelligent control strategies. A summary and outlook were made on the future development trends of key technologies for autonomous homing of parafoil systems, which can help researchers gain a comprehensive understanding of the research progress and development trends in autonomous homing of parafoil systems, and provide inspiration and reference value for further research in this area.

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• Experimental study on effects of carbon dopants on the beam divergence angles of solid propellants

  Experimental study on effects of carbon dopants on the beam divergence angles of solid propellants

  OU Yang; WU Jianjun; CHENG Yuqiang; ZHANG Yu; CHE Bixuan
  Abstract:Two kinds of carbon doped particles, graphene and toner, were used to directionally modify solid propellant. The influence of different doping ratios and working conditions on the divergence angle of the modified propellant was compared and analyzed by high-speed photography technology and a self-built beam divergence angle measurement system, so as to determine the optimal doping ratios and working conditions of the doped particles. It is found that the optimal doping ratio of graphene and toner is 7%, and the beam divergence angle of graphene is smaller, and the response time of generating stable plasma flow is shorter. At the same time, graphene is more suitable for the working conditions under the small laser energy supply, and toner is more suitable for the working conditions under the large laser energy supply.

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• Analysis of temperature control mechanism of a novel semi-active cooling device for high-speed flight vehicle

  Analysis of temperature control mechanism of a novel semi-active cooling device for high-speed flight vehicle

  GUO Qingyang; MA Rui; LI Shibin
  Abstract:Aiming at the thermal control problem of high temperature components in special cabin of advanced aircraft, a new semi-active temperature control principle was proposed. Based on this principle, a new semi-active cooling device was designed and its experimental study was conducted. The heat transfer performance and temperature control mechanism of the new semi-active cooling device under different working conditions were analyzed and compared. The results indicate that the thermal control performance of the new semi-active cooling device is significantly better, especially for the semi-active cooling device filled with 100% infiltrated aerogel, the hot end temperature is 272 ℃ at 3 000 s, which is 102 ℃ lower than that under the passive heat transfer condition, and the peak efficiency is up to 68%. With increasing of the outlet pressure of the cooling device, the time for the coolant to reach the boiling point is longer. Filling infiltration aerogel can effectively extend the duration from heat absorption to evaporation of the coolant, and it is also lighter in weight compared to other filling methods.

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• Multi-sensor cooperative planning of space objects detection

  Multi-sensor cooperative planning of space objects detection

  LONG Xi; CAI Weiwei; YANG Leping
  Abstract:Background of collaborative detection of space targets by multiple ground-based radars, to solve the issue of low detection efficiency in traditional collaborative planning methods that use the entire detectable arc segment as the decision variable, a multi-sensor collaborative detection scheduling model was established, and an adaptive immune genetic algorithm that could simultaneously determine the detection arc segment and detection start time was proposed. Considering various factors such as the space objects attribute, type, launch time, radar cross-section grade, and purpose, a multi-level fuzzy comprehensive evaluation model was constructed, and the 1-9 scale method was adopted to obtain the priority of the spatial target. In order to maximize the priority, consideringvarious constraints such as detection time, sensor capacity, and so on,an adaptive immune genetic algorithm was used to solve the problem.The performance of the planning method was evaluated from two aspects of detection resource consumption rate and task completion rate. By comparative analysis with the improved heuristic algorithm and traditional evolution algorithm, this algorithm improves the task completion rate while also reducing resource consumption rate.

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• Adaptive antidromic window moving method for spacecraft orbital maneuver detection

  Adaptive antidromic window moving method for spacecraft orbital maneuver detection

  LI Zeyue; YANG Zhen; LI Haiyang; LUO Yazhong
  Abstract:Using two line elements as data source, an adaptive method using antidromic window moving for detecting maneuvers of space objects was proposed. Adaptive window configuration model was established to get detection window for different objects. Meanwhile, cross arc prediction was integrated in order to obtain the maneuver time more precisely. Applying antidromic window moving method, the maneuver in the latest epochs can be detected. The results were compared with real maneuvers as well as in the existing literature. It is shown that the proposed method can adapt to the window configuration of maneuvering detection of space objects on different orbits. Besides, the detection success rate can reach more than 90% under the given simulation conditions. Moreover, the accuracy of maneuver time estimation is observably higher than that of existed method. Simulations of the approach proposed have demonstrated good performance in near-real-time maneuver detecting.

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• Fault tolerant control of launch vehicle boost phase considering thrust loss

  Fault tolerant control of launch vehicle boost phase considering thrust loss

  XIE Changlin; YANG Shuming; CHENG Yuqiang
  Abstract:The launch vehicle is prone to power system faults such as thrust drop in the ascending stage, and the traditional control method is difficult to meet the requirements of high precision and high stability control in the case of large interference. In this research, the adaptive augmentation control and fuzzy PD control of launch vehicle were studied, and their control characteristics were analyzed. A dynamic switching control algorithm based on fuzzy rules was proposed, and by calculating the output weight of adaptive PD control and fuzzy PD control, the optimal control scheme of the system was obtained. The control torque reconstruction and the dynamic switching control algorithm were combined to carry out fault-tolerant control research. The results show that the dynamic switching control algorithm based on fuzzy rules can effectively improve the attitude control quality. Compared with other control methods, the maximum yaw angle deviation is reduced by more than 20%, the system response time is at least 15% faster, and there is no oscillation in the control process.

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• Time efficient attitude maneuver path planning and time scaling method under complex constraints

  Time efficient attitude maneuver path planning and time scaling method under complex constraints

  YUE Chengfei; LU Ming; WU Fan; HUO Tao; CHEN Xueqin
  Abstract:For the large-angle attitude maneuver of spacecraft under complex constraints, a efficient maneuver path planning for attitude and time scaling method on 3-dimensional special orthogonal group was proposed. Aiming at handling the attitude constraints during maneuvering, a gradient-based obstacle avoidance methodology was designed and the attitude routes and desired angular velocity trajectory was obtained on the virtual time domain. Considering the maximum output torque of the actuator, an iterative nonlinear time scaling method was proposed to adjust the angular velocity/control torque. Simulation results show that the proposed method not only satisfies the attitude constraints and the control torque constraints during the spacecraft maneuver process, but also significantly shortens the maneuver time comparing with existing methods. Novel results provide a new insight for efficient constrained attitude planning and controller design.

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• Integrated online identification of aerodynamic and thrust parameters in supersonic cruise missile

  Integrated online identification of aerodynamic and thrust parameters in supersonic cruise missile

  JIANG Zhenyu; TANG Xiaobin; LIU Shuang; YANG Chengye
  Abstract:To accurately predict the aerodynamic and thrust characteristics of supersonic cruise missile during flight, improve the flight performance and mission adaptability, an integrated online identification method for aerodynamic and thrust parameters was proposed. Motion model of supersonic cruise missile powered by a solid rocket ramjet engine in the longitudinal plane was established, and a polynomial model of aerodynamic and thrust coefficients in the cruise phase was established. The unscented Kalman filter algorithm was used to conduct online identification and simulation verification of aerodynamic and thrust parameters. The identification performance was compared and verified based on flight test data. Researches show that the integrated identification of aerodynamic and thrust parameters for supersonic cruise missile is necessary and effective, and the proposed method can be applied to online parameter identification during flight.

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• Free vibration of cylindrical functionally graded tubes on bi-parameter foundation based on a higher-order beam theory

  Free vibration of cylindrical functionally graded tubes on bi-parameter foundation based on a higher-order beam theory

  MA Weili; CUI Huiru; SHEN Liulei; WANG Shiqi; PENG Fan; LI Xianfang
  Abstract:Based on the theory of high-order shear deformation beam, the governing equations for the free vibration behavior of Winkler-Pasternak elastic foundation radial function gradient hollow cylindrical pipe were derived. This method does not require the introduction of shear correction coefficient and automatically satisfies the free boundary condition of shear stress on the inner and outer surfaces of the hollow cylindrical pipe. By introducing auxiliary functions, the coupled equations for deflection and angle were transformed into a single high-order differential equation. The frequency and mode shapes of the function gradient hollow cylindrical pipe under typical boundary conditions were given. The calculation results were compared with the results in the existing literature to verify the accuracy of the proposed theory. It can provide higher precision one-dimensional elastic theoretical solutions for the common Winkler-Pasternak elastic beam structures in engineering. Research results show that the gradient parameter and elastic foundation stiffness coefficient of the function gradient material have a significant impact on the natural frequency value. Compared with the high-order natural frequency, the stiffness coefficient has a more significant impact on the low-order natural frequency.

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流体动力与机电控制

• Resonant frequency control method of acoustic mechanical antenna

  Resonant frequency control method of acoustic mechanical antenna

  CUI Yong; LI Liangya; WANG Chen; HUANG Yuping; YUAN Zhihong; TAO Yunfei
  Abstract:Acoustic mechanical antenna is one of the important types of mechanical antenna, the resonant frequency of acoustic mechanical antenna is highly coupled with its natural frequency. However, the current acoustic mechanical antenna is limited by material size and has high resonant frequency, which can not to meet the needs of very low frequency or lower frequency band. In order to control the resonant frequency of acoustic mechanical antenna, the vibration modeling of acoustic mechanical antenna was carried out. Three methods were proposed:adding unilateral fixed constraint, increasing free end mass and removing some materials of antenna. Proposed method was verified by finite element simulation. Results show that the three methods can effectively control the resonant frequency of acoustic mechanical antenna, and are in good agreement with the analytical model. Influence of three methods of regulating resonant frequency on the electric field or magnetic field intensity radiated by the antenna was studied through the stress distribution, which has important reference significance for the design of acoustic mechanical antenna.

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• Path planning of a multiple AGV system in unmanned warehouse with bottom passable shelves

  Path planning of a multiple AGV system in unmanned warehouse with bottom passable shelves

  YANG Hongjiu; ZHAO Guowei; LI Hongbo; CHENG Fuyang
  Abstract:The multiple AGV (automated guided vehicle) system is prone to conflict, collision and deadlock in the process of carrying. Therefore, the A* algorithm was improved by introducing multi-valued grid and traffic rules to solve the path planning problem for the multiple AGV system in scenarios where there was passable space beneath shelves. To improve handling efficiency of the multiple AGV system, the planned path was optimized by adding shelf recall mechanism, turning cost and heat cost. A binary heap data structure was also used to improve calculation speed of the path planning. The simulation results show that the improved A* algorithm has the advantages of fast solution and strong deadlock resistance, and can quickly complete the path planning of multi-AGV system in this scenario.

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• Position sensorless control of permanent magnet synchronous motors over the full speed range

  Position sensorless control of permanent magnet synchronous motors over the full speed range

  LIU Jilong; FU Kangzhuang; MAI Zhiqin; LI Kefeng; ZHANG Weiwei
  Abstract:In order to solve the problems of slow starting speed of IF control and weak starting torque ability, the high frequency pulse voltage injection method was used to complete zero low speed starting of the motor, and combined with the effective flux method in the middle and high speed area, the position sensorless composite control strategy was formed in the full speed range. In order to achieve smooth switching between the two control methods, a hysteresis switching strategy combined with a state machine based on the speed transition region was proposed. The entire speed range was divided by the proposed strategy into the zero-low speed area, the transition area, and the medium-high speed area. When the motor entered the transition area from the medium-high speed area, the high frequency pulse voltage injection method was started in advance to stabilize the position estimation process and prepare for the switch. In order to reduce the impact of the injected high frequency voltage on the position estimation process of the effective flux method, the input and exit of the high frequency pulse voltage injection method were realized by soft switching in the speed transition zone. In order to solve the coupling problem when two position estimation methods work simultaneously in the speed transition region, a double synchronous rotating coordinate system was set up to realize the decoupled control of rotor position estimation. The effectiveness of the proposed method was verified on a three-phase permanent magnet synchronous motor.

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• Analysis of cavitation-induced vibration sensitivity in regulating valve using multiple measuring points

  Analysis of cavitation-induced vibration sensitivity in regulating valve using multiple measuring points

  LIU Xiumei; WEI Jianqiu; LONG Zheng; LI Beibei; SUN Shenzhen
  Abstract:Aiming at the difference in the cavitation sensitivity of the control valve at different measuring points of the regulating valve body, study on the difference of cavitation induced vibration and the cavitation sensitivity of different measuring points was carried out. A test platform for cavitation-induced vibration acceleration signal acquisition of regulating valve was built, and the acceleration signals of cavitation vibration of regulating valve at multiple measuring points were simultaneously collected. Two characterization parameters, the acceleration level ratio and the gravity frequency, were proposed. Frequency spectrum of the cavitation vibration signal of regulating valve was divided by the 1/3 octave frequency spectrum, and finally the frequency band most sensitive and location of measuring points to cavitation development was obtained. Results show that the vibration signals of measuring point on the same surface of the regulating valve body are similar, and the signals on different surface are significantly different. Vibration signals of the regulating valve are anisotropic. Development of cavitation extent mainly causes the vibration intensity of the frequency band above the center frequency of 10 000 Hz to increase. It is suitable for monitoring cavitation state of control valve.

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• Deterministic robust backstepping motion tracking controller for proportional valve-controlled pneumatic cylinder system

  Deterministic robust backstepping motion tracking controller for proportional valve-controlled pneumatic cylinder system

  PU Chenwei; LIU Lei; HE Di; QIAN Pengfei
  Abstract:In order to achieve high-precision robust control of pneumatic cylinder motion trajectory, the mathematical model of proportional valve-controlled pneumatic cylinder system was established, and a non-linear deterministic robust controller was designed on the basis of the backstepping method, which can effectively suppress the effects of system model parameter uncertainty, unmodelled dynamics and external disturbances. The Simulink module in MATLAB was used to construct a simulation model of the pneumatic cylinder motion trajectory tracking control system. A real-time control system for pneumatic cylinder motion trajectory based on a non-linear deterministic robust controller was developed using xPC-Target in MATLAB/Simulink. The simulation results show that the designed controller is feasible. The test results show that the controller can effectively track the reference trajectory, with a maximum tracking error of 0.89 mm for a 0.3 Hz sinusoidal trajectory, which is about 2.97% of the amplitude, and 1.02 mm for a 0.4 Hz sinusoidal trajectory, which is 3.4% of the amplitude.

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• Time-delay estimation tracking control of flexible-joint space robot based on low-pass filter

  Time-delay estimation tracking control of flexible-joint space robot based on low-pass filter

  XU Hezhen; YU Xiaoyan; ZHANG Yuhan; CHEN Li
  Abstract:In order to solve the joint tracking control and vibration problem of flexible-joint space robot system in the pre-grasping stage when the position and pose are not controlled, the dynamic equations of a free-floating three-bar flexible-joint space robot system are established using the Lagrangian equation in conjunction with the principle of momentum conservation. In order to improve the equivalent stiffness of flexible-joint, a joint flexible compensation method was introduced. The flexible-joint space robot system was divided into slow and fast systems by singular perturbation theory. On this basis, a sliding mode control method with time delay estimation as the main framework was designed for the slow variable systems, while combining it with a low-pass filter to eliminate the system chattering problem caused by sliding mode control. A linear velocity difference feedback control system was designed for the fast-changing system to suppress the flexible vibration problems introduced by the flexible joints. Simulation verification demonstrates that the space robotic arm is capable of quickly and steadily tracking the desired trajectory within a limited time, confirming that the control scheme possesses good robustness and reliability.

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• Analysis and evaluation method for invulnerability of weapons

  Analysis and evaluation method for invulnerability of weapons

  HUANG Tong; 高钦和; LIU Zhihao; WANG Dong; MA Dong; GAO Lei
  Abstract:In view of the problem that the current evaluation of the survivability of weapons and equipment is mainly statistical and lacks physical support, in order to establish the transmission relationship between the structural parameters and the protective performance of each component, the concept of invulnerability was proposed, and the invulnerability analysis method based on the limit damage and the invulnerability characterization method based on the generalized protection time were proposed. And through the index to the quantitative mechanism of combat missions, the task-oriented invulnerability evaluation method was proposed. Driving performance invulnerability was studied as an example. Results show that:the invulnerability analysis method based on the limit damage can realize the construction of physical transfer relation from physical space to performance space; the invulnerability characterization method based on the generalized protection time can reflect the comprehensive influence of amplitude distance and difficulty degree on invulnerability; the task-oriented invulnerability evaluation method can introduce operational mission requirements into invulnerability evaluation and reduce the influence of subjective weight assignment on evaluation results. Case analysis verify the feasibility and effectiveness of the proposed method.

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• Influences of design parameters on shock isolation performance of integrated quasi-zero stiffness isolator

  Influences of design parameters on shock isolation performance of integrated quasi-zero stiffness isolator

  DING Bosen; LIU Haiping; ZHU Dongmei
  Abstract:The shock isolation performance of the integrated quasi-zero stiffness isolator (as also be called “integrated isolator”) was studied. The attenuation period, oscillation frequency, maximum acceleration ratio and maximum displacement of shock response were selected as evaluation indexes, respectively. The influences of linear stiffness ratio and geometric design parameters on the shock isolation of the integrated isolator under half-sine pulse acceleration excitation were emphatically studied by using the fourth-order Runge-Kutta method. Calculation results show that the integrated isolator has better acceleration attenuation performance than the linear isolator after the shock with a long duration. The smaller outer wall height and the larger wall thickness are beneficial to improve the shock isolation performance. The relevant research can provide guidance for the engineering application of the integrated quasi-zero stiffness isolator.

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电子科学与技术.计算机科学与技术.物理学

• Analysis on single-event radiation characteristics for a bandgap reference in bulk CMOS technologies

  Analysis on single-event radiation characteristics for a bandgap reference in bulk CMOS technologies

  WEN Yi; 陈建军; LIANG Bin; CHI Yaqing; XING Haiyuan; YAO Xiaohu
  Abstract:In order to analyze the single-event radiation characteristics of BGR(bandgap reference) under extreme conditions such as space environments, a BGR test chip was designed and implemented in both 65 nm and 28 nm bulk CMOS technologies. Pulse laser single-event simulation experiments were conducted to study its single-event radiation characteristics. The experimental results show that when the pulsed laser energy is sufficiently high, the output voltage of BGR significantly increases after irradiation and the voltage cannot recover after annealing, this indicates that SHD(single-event hard damage) presents in the BGR. Further studies indicate that the bipolar junction transistor in BGR is the sensitive device to induce hard damage. The investigation provides important theoretical references for SHD hardening design of BGR in bulk CMOS technologies.

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• Satellite domain corpus construction and named entity recognition

  Satellite domain corpus construction and named entity recognition

  XU Cong; SHI Huipeng; CHEN Zhimin; ZHANG Xinyu; WANG Jing; YANG Jiasen
  Abstract:Aiming at the lack of named entity corpus in the satellite domain and the low recognition performance of existing algorithms, a satellite domain entity labeling method considering fuzzy boundaries was proposed, constructed a corpus containing 8 common satellite domain entities where the granularity was finer and the coverage was wider in comparison with the existing corpora in this field. Based on this, a transfer learning and multi-network fusion satellite domain entity recognition algorithm was proposed. Algorithm used pretrained bidirectional encoder representations for transformers to smoothly transfer the semantics of the corpus for subword-level features, a BiLSTM (bi-directional long-short term memory) network for capturing contextual information to determine boundaries, and label prediction was achieved using a conditional random field as a decoder. Experimental results show that, compared with traditional models such as BiLSTM, the proposed algorithm has better recognition performance where the F₁-score in 8 entities is all above 92% and the micro-average F₁-score reaches 96.10%.

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• Inversion modeling method utilizing ship′s internal magnetic field

  Inversion modeling method utilizing ship′s internal magnetic field

  HE Baowei; ZHANG Junhong; LIU Shengdao; ZHOU Guohua; TANG Liezheng; ZONG Jingwen
  Abstract:The integral equation method is widely used in ship′s magnetic field inversion modeling, but the model requires enough measurement points to obtain the ship′s magnetic field at a specific depth. To address the problem that the integral equation method uses the near-field magnetic field to model with poor accuracy, an improved measure by adding constraint equation was proposed. The numerical simulation of the magnetic field of a thin steel plate model and a 3D ship model was carried out respectively. The finite element method was used to initialize the selection of the ship′s internal measurement points. The inversion modeling was constructed based on the measured values of the internal magnetic field of the ship and the singular value decomposition method was used to solve the magnetic source parameters and predict the external space magnetic field. It shows that the root mean square error of the prediction results of the external space magnetic field of the ship is less than 12%. The magnetic field measurement experimental verification of the ship cabin model shows that the root mean square error of the prediction of the external magnetic field from the internal magnetic field of the cabin is about 13%, which proves the effectiveness of the proposed method and can improve the instability and insufficient accuracy of the traditional inversion model. The research results can provide ideas for the algorithm design of closed-loop degaussing of ships.

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• Analysis of linearity and correlation of acoustic spread spectrum signal in multipath reverberation channel

  Analysis of linearity and correlation of acoustic spread spectrum signal in multipath reverberation channel

  TANG Yongzhuang; ZHOU Qidou; XIE Zhiyong; LYU Xiaojun; JI Gang
  Abstract:To analyze the correlation and linearity of acoustic spread spectrum signals in shallow water multipath channels, a virtual source calculation model for Pekeris waveguides in shallow waters with frequency attenuation and seabed loss was established. Pulse signals and spread spectrum signals in shallow seas were simulated, and the linearity of spread spectrum signals in a multipath reverberation environment was preliminarily investigated through experiments conducted in a reverberation chamber. Simulation results show that the frequency domain solution of the virtual source method is consistent with that of the normal mode method, and the same low-frequency mode dispersion phenomenon as the normal mode method can be obtained through the virtual source method, verifying that the virtual source method is suitable for low-frequency problems in ideal shallow water waveguides and Pekeris waveguides; when modal dispersion occurs, the correlation performance of low-frequency spread spectrum signals is better than that of high-frequency signals under the same conditions. Experimental results show that when the time-domain waveform of a low-frequency pulse is distorted and broadened, the spread spectrum signal of the same frequency can accurately measure the geometric delay of the reflected signal, demonstrating that the low-frequency multipath effect can still be regarded as the linear superposition of all "path" signals.

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• Design and magnetic field analysis of linear phase-shifting transformer with hairpin filling structure

  Design and magnetic field analysis of linear phase-shifting transformer with hairpin filling structure

  ZHAO Jinghong; XUE Jie; YAN Sinian
  Abstract:Based on the original linear phase-shifting transformer, a linear phase-shifting transformer with a hairpin filling structure was designed with reference to the theory of linear motor, which effectively solved the problems of complicated winding method, large size and modular series-parallel connection. At the same time, it improved the problems of reduced primary side excitation current density and air gap magnetic field distortion caused by the semi filled slot at the connection during modular connection. Working principle of the linear phase-shifting transformer system was briefly introduced; the design method of linear phase-shifting transformer with half-filled slot structure was proposed with reference to the design method of linear motor and rotary motor; the hairpin structure was adopted to eliminate a series of problems caused by the half-filled slot structure at the connection; finally, the finite element simulation was used to verify the comparison. Results show that the designed linear phase-shifting transformer with a hairpin structure has a good output waveform and a small distortion of the air gap magnetic field.

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• Inversion method of submarine steady electric field using point-type current source and Tikhonov regularization

  Inversion method of submarine steady electric field using point-type current source and Tikhonov regularization

  ZHANG Jianchun; LIU Chunyang; ZHAO Yulong
  Abstract:In order to evaluate the distribution characteristics of submarine underwater corrosion related steady electric field, starting from the mechanism of submarine underwater corrosion related steady electric field, a forward model of submarine underwater corrosion related steady electric field was established based on the equivalent point-type current source theory. And the current intensity of the equivalent point-type current sources was solved by Tikhonov regularization according to the measured electric field data. The effectiveness of the proposed method was verified by commercial finite element software COMSOL. The results show that when inverting the electric field value from depth of 38 m to a water depth of 42.5 m and 33.5 m, the relative root mean square error, maximum relative error, and peak to peak relative error do not exceed 0.06. Even if the calculated depth reaches 45 m, the relative root mean square error is still less than 0.21. When the noise standard deviation is 0.1 times the maximum value of the actual electric field, the inversion error is still less than 0.1. This algorithm has strong noise resistance and high accuracy, can be used in engineering practice.

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• High precision frequency estimation algorithm for autocorrelation weighted fusion

  High precision frequency estimation algorithm for autocorrelation weighted fusion

  LIU Kang; 何明浩; CHEN Changxiao; ZENG Sha; LI Zheng
  Abstract:In order to ensure the performance of radar countermeasure reconnaissance system in complex electromagnetic environment, a multi-segment signal frequency estimation algorithm based on autocorrelation weighted fusion was proposed. Autocorrelation processing was performed on each segment of the noisy signal to obtain a high SNR sinusoidal signal with zero initial phase and the same frequency as the original signal. The arcsine operator was used to construct a support matrix to perform real-time weighted fusion of the autocorrelated signals. The reference signal was established on the basis of the rough estimation, and the high-precision frequency estimation result was obtained by minimizing the error function. The simulation results show that, compared to existing algorithms, the algorithm not only improves the accuracy significantly, but also has stable estimation performance under the conditions of different SNRs, signal lengths and signal anomalies, while satisfying the low computational cost, which provides a reference for radar countermeasures intelligence reconnaissance based on multi-sensors.

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• Security evaluation of Midori128 cryptographic algorithm under integral fault analysis

  Security evaluation of Midori128 cryptographic algorithm under integral fault analysis

  WEI Yuechuan; HE Shuiyu; PAN Feng; WANG Xiangru
  Abstract:In order to study the security of the Midori128 cryptographic algorithm against integral fault attack, the relationship between integral distinguisher balance position, fault ciphertext, and the round key was established, and the last round key of the algorithm could be recovered by key search, and then the master key could be recovered by using key extension algorithm. The theoretical analysis shows that the time complexity of recovering the correct key is 2²¹ and 2²⁴ when using 3 and 4 rounds of integral distinguisher for the integral fault attack, respectively. The accuracy, success rate, and elapsed time were used to simulate the attack process of the fourth round of injection fault, and the master key of the algorithm was successfully recovered. Comparison experiments were conducted for different plaintext groups and keys. The two sets of fault security analysis schemes conclude that the round function of the Midori128 algorithm is vulnerable to integral fault attacks and requires additional protection such as fault detection for at least the last 6 rounds while the algorithm is running.

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