Abstract:Digital twin is a new state-of-the-art technology to realize the interconnection and integration of physical and information world for complex equipment. It has a broad prospect in simulation，monitoring，diagnosis， and optimization control of a series of complex products. This paper focuses on investigating the digital twin kinemat? ics and modeling analysis，data transmission and bidirectional mirroring of complex equipment，taking the driving and bolting integration equipment as the objective. In the field of behavior consistency of digital twin，the fast kine? matics simulation analysis of driving and bolting integration equipment is realized based on historical simulation data? base and physical simulation model. In addition，in the field of real-time state mapping，the virtual real-time map? ping technology is proposed，and through collecting and transferring twin data online，the information transmission from real to virtual is realized based on asynchronous transmission. In the process of lifting，feeding，digging and cin? der recovery of the driving and bolting integration equipment，the program processing delay is limited to 10-5 sec? onds. The error of kinematics interpolation processing is less than 3% and the frequency of digital twin platform for the developed driving and bolting integration equipment is over 74.3 frames per second. Finally，the remote realtime state mapping and online monitoring of work procedure are accomplished for the driving and bolting integration equipment in the environment of integrated service.

Abstract:To enhance the mechanical performance of lattice-infilled structures, this paper presents a multiscale topology optimization method based on ordered solid isotropic material with penalization (Ordered SIMP) interpola? tion model for lattice-solid hybrid structure design. The X-shape cubic cell is selected as the basic lattice structure, and polynomial functions are established through numerical fitting to relate the lattice relative density to its physical properties. Then, for macro structure topology optimization, relative densities of the macro elements are employed as the design variables, and a multi-material interpolation model spanning from variable-density lattices to solid is de? veloped based on the Ordered SIMP interpolation. Finally, a multiscale topology optimization problem is formulated to minimize the structural compliance of the lattice-solid hybrid structures subject to a material volume fraction constraint. Numerical examples and mechanical testing are presented to demonstrate the effectiveness of the proposed ap? proach compared with pure lattice-infilled structure designs.

Abstract:The mathematical model of globoidal worm drive with high-order modification is established system? atically. The curvature parameters，meshing function and curvature interference boundary function of worm pair are derived by differential geometry and meshing theory. It is proved that the tooth surface of globoidal worm is an unde? velopable ruled surface，which is consistent with the principle of tooth surface formation. The least squares method is used to fit the dimensionless modification data to obtain a universal high-order modification curve. Based on the curve，the calculation formula of the process transmission ratio is derived，and the high-order modification worm transmission is obtained. According to the numerical examples of different modification curves，the analysis shows that the high-order modification can eliminate the constant contact line of the tooth surface of the original globoidal worm，and effectively increase the conjugate area of the tooth surface of the worm pair. After the modification，the full length of the worm can be used and the bearing capacity is strong. However，there is a curvature interference line on the tooth surface of the worm pair after high-order modification，which may lead to undercutting of the worm pair.

Abstract:In order to solve the problem that key state parameters such as mass-center sideslip angle of the ve? hicle can not be directly detected in the torque control of four hub-motor driving vehicles，and the measured values such as vehicle speed are easy to be interfered by random errors，a seven degree of freedom dynamic model of four hub motor-driven electric vehicles is established，and the filtering estimation of the driving state parameters of the whole vehicle is carried out. Based on robust filtering principle and unscented particle filter algorithm，a vehicle state filtering estimation method was proposed. Using adaptive robust unscented particle filter，the accurate filtering estimation of longitudinal speed，lateral velocity and mass-center sideslip angle in the process of electric vehicle driving was realized. The joint simulation experiment platform of CarSim and MATLAB / Simulink was built to verify the estimation algorithm. The results show that the dynamic model of four hub-motor driving vehicle has high predic? tion accuracy for vehicle driving state，and the adaptive robust unscented particle filter algorithm can effectively fil? ter the measured parameters and has high estimation accuracy.

Abstract:Due to the influence of the cogging structure，there will be cogging torque in the brushless direct cur? rent motor（BLDCM），which will increase the torque ripple and therefore affect the performance of BLDCM. To solve the above problems，BLDCM used in the Electro-hydraulic brake system（EHB）is taken as the research ob? ject，and the structure parameters are analyzed and improved to suppress BLDCM′s cogging torque. Firstly，by deriv? ing and analyzing the expression of cogging torque，it is found that its value is determined by basic structural param? eters and Fourier decomposition coefficients Br（nz/2p） and Gn Secondly，the function expressions of eccentricity，pole arc coefficient，auxiliary slot and Fourier decomposition coefficient are deduced respectively，and the relationship between them and cogging torque is obtained. Finally，the change of cogging torque is studied by finite element method under three conditions：the change of eccentricity，the change of polar arc coefficient and the addition of aux? iliary slot. The results show that when the eccentricity，polar arc coefficient and auxiliary slot shape are 7.90 mm， 0.74 and ellipse respectively，the corresponding peak cogging torque is reduced by 96.65%，90.48% and 86.74% re? spectively，and the cogging torque is obviously suppressed.

Abstract:Clarifying the differences of mechanical properties in different anatomical regions of bone can provide an important basis for constructing the finite element model of the bone with high biofidelity. One sample was pre? pared from each of the anterior，posterior，medial，and lateral anatomical regions of the bovine femoral shaft. Each sample was tested at 18 points utilizing a Berkovich nanoindenter tip，and the time history of the loading force and in? dentation depth was recorded to obtain the indentation modulus and hardness. The indentation modulus of the ante? rior，posterior，medial and lateral regions of the long bone were 20.78 ± 2.66 GPa，18.66 ± 2.57 GPa，16.39 ± 2.29 GPa，21.57 ± 2.19 GPa respectively，and hardness were 0.65 ± 0.79 GPa，0.58 ± 0.08 GPa，0.44 ± 0.06 GPa，0.61 ± 0.15 GPa respectively. Variance analysis showed that anatomical region had a significant effect on indentation modulus and hardness（p < 0.001）. Multiple comparisons between groups showed that the indentation modulus and hardness of the anterior specimen were significantly higher than those of the lateral specimen，the indentation modu? lus and hardness of the medial specimen were significantly higher than those of the lateral specimen，the hardness of the posterior specimen was significantly higher than that of the lateral specimen，and the indentation modulus of the medial specimen was significantly higher than that of the lateral specimen. Therefore，the use of heterogeneous mate? rials can help to improve the biological fidelity of the finite element model of the long bone.

Abstract:Aiming at the time-consuming problem of traditional Monte Carlo calculation for radiation transmis? sion，this paper develops an improved Monte Carlo method，which solves the reflection and scattering energy through proportional iterative accumulation method，thereby greatly reducing the calculation time. The direct evalua? tion method is introduced，and the closed system containing participating media（square and circular as examples） is used as an example to analyze the influence of the grid density，the number of emitted energy beams and the physi? cal parameters on the calculation accuracy of the improved Monte Carlo method. When the optical thickness is 0.005，the relative root mean square error of radiation flux for the square cavity and the circular cavity is 0.002 5 and 0.002 3 respectively by using the improved Monte Carlo method，while the corresponding errors are 0.008 0 and 0.003 7 respectively when the traditional Monte Carlo method is used. It can be seen that under the same calculation conditions，the improved Monte Carlo method has higher accuracy for the radiation heat transfer problem. The influ? ence of the tracking energy beam number on the calculation error is further studied，and the fitting relationship be? tween the calculation error and the tracking energy beam number is given，which provides support for the selection of the energy beam number.

Abstract:Aiming at the problems of uncertain measurement noise，serious influence of accumulated error and sensitive initial value in the process of semi-trailer state estimation，a double adaptive unscented Kalman filter algo? rithm（FFUKF）is proposed，which is suitable for estimating several state variables of semi-trailer such as hinge angle and vehicle speed. Based on the established 12-degree-of-freedom nonlinear dynamic model and tire model of semi-trailer car，through the measured wheel speed and vehicle acceleration and other information，firstly，fuzzy control is used to adaptively adjust the slip rate tolerance，comprehensively judge the stable state of each wheel，and estimate a vehicle speed through the wheel speed；At the same time，fuzzy control adaptively adjusts the measurement noise，and estimates the hinge angle and another vehicle speed according to dynamics by using unscented Kal? man algorithm；Then，Kalman filtering algorithm is used to fuse the estimation results of the two methods，so as to realize the real-time estimation of the longitudinal and lateral velocity，yaw rate and the articulation angle between trailer and tractor. At last，the multi-condition simulation experiment is carried out in Simulink/TruckSim cosimulation environment，which proves that the proposed double adaptive unscented Kalman estimation algorithm （FFUKF）has strong adaptability，stability and robustness，has higher estimation accuracy than the ordinary fuzzy adaptive unscented Kalman（FUKF），and can effectively overcome the cumulative error. Even if the initial estima? tion value is inaccurate and ABS control input is available，the vehicle speed and hinge angle can still be accurately estimated in real time.

Abstract:To solve the problem of low error fault recognition rate of chiller sensors deviation，a sensor error fault diagnosis method based on Convolutional Neural Network（CNN）and Gated Recurrent Unit（GRU）fusion Net? work model（CNN-GRU）is proposed. This method utilizes GRU to remember the different time correlation of each sensor due to the different dynamic response characteristics of each sensor of the chiller，and overcomes the short? coming that CNN can only extract the real-time characteristics of time series in the fault diagnosis of sensor deviation of the chiller. First，the sensor real-time characteristics of time series are automatically extracted using CNN，and then GRU with a short and long-term memory capacity is used to realize the different time correlation of memory for the chiller sensor，so as to make full use of the feature information in the time series to characterize and model the data，and effectively improve the fault recognition rate of chiller sensor bias. Compared with CNN，PCA and autoen? coder methods，the experimental results show that the error fault identification rates of temperature and pressure sensors are more than 85% and 90%，respectively. The identification rate of deviation fault is more than 83%，which proves that the generalization ability of this method is good. The method has good symmetry for the fault recognition rates of the same sensor and the fault magnitudes are opposite to each other. The error fault identification rate of this method is higher than that of other methods，and especially for small error fault identification rate，it shows more ob? vious superiority.

Abstract:This paper designed a step-shaped calibrator，which is easier to obtain the coordinates of the calibra? tion points and only requires the line laser to align the marked points on the calibrator once，and easier to operate than the spherical calibration method；At the same time，based on the step-shaped calibrators，this paper proposes a hand-eye calibration algorithm for line laser sensors. The algorithm uses the RANSAC（Random Sampling Consensus）algorithm to fit the calibration points，and uses the least square method to solve the hand-eye calibration ma? trix. This calibration algorithm does not need to modify the coordinates of the calibration point. The experimental re? sults show that the accuracy and stability of the step-shaped calibration method are better than those of the spherical calibration method，and the method is simple to operate and can meet most applications in the field of automatic pro? cessing.

Abstract:With the development of informatics and data science tools，the application of various computer sci? ence softwares in the field of material simulation calculation continues to increase. In order to speed up the screening of catalysts，a research on how to improve and enhance material screening based on information tools was carried out，and a first-principles-based high-throughput material integrated computing framework GASpy（Generalized Adsorption Simulator for Python）was introduced. The framework supports the automated process management of computing tasks，DFT（Density Functional Theory）calculations can be called with the help of Fireworks，and the calculation results and intermediate steps can be saved to the MongoDB database. The platform supports the dynamic binding with different high-performance computing clusters，and supports the generation and submission of largescale computing jobs. The platform also supports data extraction and automatic storage. GASpy is used to test the crystal structure obtained on the material website on Tianhe-1，optimize the crystal structure and calculate the ad? sorption energy. The results show that the combination of various informatics tools can achieve large-scale automated DFT material simulation calculations more flexibly and efficiently and has a good application prospect in the field of analog electrocatalysis.

Abstract:In public-key cryptosystems（PKI），whether it is RSA cryptography or elliptic curve cryptography （ECC），modular inversion operations are very critical operations. The premise of modular inversion operations is that the greatest common divisor（GCD）of the two numbers is 1，otherwise the result is meaningless. Based on the existing binary modular inversion algorithms，an algorithm that can simultaneously find the GCD and perform modu? lar inversion operations is proposed，and the algorithm is optimized and implemented in hardware using VERILOG HDL language. Through functional simulation and FPGA verification，the results show that this design can correctly perform the modular inversion operation of large number from 32 to 1 024 bits. The design is applied to a PKI module of an automotive security chip，using UMC 55 nm process for tape-out，and the chip area is 10 mm2. When the work? ing voltage is 3.3 V and the clock frequency is 200 MHz，the power consumption is about 30.2 mW.

Abstract:The MD5 algorithm is a widely used Hash algorithm，which occupies an important position in digital signatures and signature verification. The efficiency of the algorithm will directly affect the speed of signature and sig? nature verification. This paper proposes an optimized MD5 algorithm，which uses a three-stage adder to replace a four-stage adder，optimizes the cyclic shift operation to shorten the critical path of the single-step operation of the MD5 algorithm，and implements the hardware in VERILOG HDL language. Through simulation and FPGA verifica? tion，the results show that the design function is correct and consumes fewer hardware resources and has a large data throughput. The design is applied to a cryptographic security chip，which uses a 0.18 μm process for MPW tape-out with a chip area of 6 mm2. When the clock frequency is 150 MHz and the voltage is 3.3 V，the power consumption is about 10.7mW.

Abstract:Square root calculating is widely used in numerical analysis，modulation-demodulation，image pro? cessing and other fields. Applying Coordinate Rotation Digital Computer（CORDIC）algorithm to square root calculat? ing is a new application. However，the accuracy of the basic CORDIC algorithm must be guaranteed by the times of iterations，and a larger number of iterations will cause problems such as excessive delay. By using methods such as establishing look-up tables，one-way rotation，merging iterations，and eliminating compensation factors，an im? proved CORDIC algorithm that can eliminate most of the iterative operations is proposed for square root calculations. Compared with the basic algorithm to calculate the square root，the improved algorithm uses half the clock cycle to get the output result，greatly reduces the output delay，and can achieve high calculation accuracy，which is more suitable for applications with high real-time requirements.

Abstract:Aiming at the problems of traditional chip detection methods，such as low detection efficiency，high requirements and poor applicability，a chip detection framework based on the electromagnetic side channel and ma? chine learning method is proposed．Firstly，on the basis of holding the genuine chip，the feature vector is extracted by introducing the neural network and various feature extraction methods，and the instruction signal of the positive sample is used as the template library. Then，the near-field electromagnetic signals of the chip to be tested are di? vided into frames，and the features of each frame are extracted. Finally，the feature vectors are input to One-Class Support Vector Machine with improved kernel function for scanning matching，so as to achieve the purpose of chip detection. The experimental results show that the proposed method can be applied to the detection of counterfeit chips that have been re-marked such as shoddy chips and fake chips.

Abstract:Long-distance urban gas-insulated transmission line（GIL）has many complicated shell structure such as expansion joints and gas basin insulators，which will cause the time delay of vibration signal propagating along the GIL shell，and then affect the positioning accuracy of vibration fault location on-line monitoring system based on time difference method. In order to clarify the influence of GIL complicated shell structure on the propaga? tion process of vibration signal and provide the basis for the improvement of the subsequent GIL breakdown fault loca? tion method，the propagation equation of vibration signal in the fluid and solid field and the coupling relationship be tween the two fields are analyzed theoretically，and the acoustic-structure coupling finite element numerical simula? tion method for the propagation process of vibration signal in GIL is presented in this paper. Then，the propagation characteristics of vibration signal in GIL shell under different excitation modes are studied. The experiment of vibra? tion propagation characteristics of GIL shell is carried out in Nantong 220kV GIL engineering site，and the typical wave velocity and time delay of vibration signal through 220kV GIL expansion joint，gas basin insulator，elbow and support are obtained. At the same time，a finite element simulation model consistent with the experiment condition is also established，which verifies the feasibility and effectiveness of the proposed numerical simulation method for vi? bration signal propagation in GIL. The results show that for the S-wave vibration signals monitored by the vibration fault location on-line monitoring system，the complicated shell structure of 220kV GIL can produce a delay ranging from 0.1ms to 1.1ms.

Abstract:With the increasing scale of modern power grid and the large-scale access of distributed generation， the problems of strong harmonic，high noise and dynamic signal change will reduce the accuracy of the synchronous phasor measurement algorithm. In order to accurately measure the synchronous phasor parameters of modern power grid，a algorithm based on the second-order Taylor dynamic phasor model and the improved matrix pencil is pro? posed，which can be used to accurately measure the amplitude and angle parameters of synchronous phasor in power system under dynamic conditions. Firstly，the algorithm is deduced mathematically，and then the measurement accu? racy is evaluated in detail according to the experimental cases specified in the test specification of synchronous pha? sor device in our country. The experimental results show that the algorithm has a high measurement accuracy under the conditions of frequency deviation and amplitude modulation，which meets the requirements of the detection specifications and has a certain engineering application value.

Abstract:Due to the short transmission distance of power line communication，a mixed power line and freespace optical（PLC/FSO）communication system with the decode and forward protocol is studied. First，the math? ematical models for the mixed system is established by assuming the PLC and the FSO channels following the lognormal and Gamma-Gamma distributions，respectively，where the pointing error in the FSO link is also considered. Then，closed-form expressions for the outage probability，bit error rate，and the channel capacity are derived. Fi? nally，simulation results are provided to verify our analytical results. Numerical results show that impulsive noise， turbulence，and the pointing error affect the system performance.

Abstract:In order to effectively extract the characteristics of electric shock faults and realize the separation of electric shock current from residual current，this paper proposes a new method of electric shock current extraction based on the combination of Variational Mode Decomposition（VMD）and Long Short Term Memory（LSTM）. The parameters of VMD［K，α］were optimized by fruit fly optimization algorithm to obtain the optimal combination of pa? rameters［6，280］. Based on the mutation characteristics of the optimal modal component of the residual current de? composed by VMD，the growth rates η1 and η2 of the sum of the current amplitudes in adjacent periods are defined as the characteristic quantities for judging electric shock accident. The electric shock current signal is reconstructed from the six layers modal component signal，and the electric shock current detection model based on LSTM network is constructed. The results of 240 groups of electric shock signals show that，when at least one of η1 and η2 is greater than 1%，electric shock occurs，otherwise no electric shock accident occurs. Compared with the VMD-BP and VMD-RBF detection models，the average correlation coefficients of the VMD-LSTM detection model are increased by 6.2% and 2.3%，respectively，and the average root mean square error is reduced by 36.8% and 27.1%，respectively. The method proposed in this paper has higher detection accuracy. The research results provide a certain reference for the development of residual current protection devices based on the electric shock current of the biological body.

Abstract:To achieve the accurate output direct-current（DC）offset cancellation with fast response to the change of input DC offset introduced by the gain adjustment in the zero-intermediate-frequency receiver，a hybrid DC offset cancellation circuit is proposed. The circuit combines the advantages of analog and digital DC offset cancel? lation technology，minimizing the output residual DC offset and reducing the response time. The analog DC offset cancellation can automatically eliminate the input DC offset at each stage in real time，and the digital DC offset can? cellation further reduces the final output DC offset of the receiver by automatic calibration. An I/Q mismatch calibra? tion circuit is also proposed to automatically calibrate the I/Q gain mismatch of the zero-intermediate frequency re? ceiver. The programmable gain amplifier（PGA）circuit with the proposed DC offset cancellation and the gain mis? match automatic calibration circuit are fabricated in 65 nm CMOS process. The measurement results show that the maximum output DC offset of the PGA is 2 mV and the gain adjustment is strictly monotonic. The output I/Q gain mis? match after automatic calibration is less than 0.1 dB. The circuit has fast response time and only needs power-on cali? bration without the involvement of digital baseband circuit. The performance of the circuit fully meets the system re? quirements of wideband communications such as IEEE 802.11ax-2021 receiver.

Abstract:The natural switching trajectories of direct-current（DC）side voltage and AC side current of T-type three-level rectifier are presented in this paper. Based on this trajectory，the natural switching control method is de? veloped by combining the direct power control theory with the natural switching trajectory theory. Under this control method，when the load is disturbed，the output current overshoot is serious and the dynamic process of the system is not smooth. In view of this phenomenon，according to the idea of current peak control in DC converter，a current peak control strategy suitable for natural switching control method is proposed，that is，adding a third running track to the original natural switching track and directly limiting the output current，so as to make the dynamic process of the system more smooth. It is verified in MATLAB 2019a simulation environment.

Abstract:The construction of a New Power System with mainly renewable energy and diversification of electri? cal load is the essential path to achieve the“carbon peak and neutrality”target in China. Facing the dual uncertainty challenge of both source and load，it sets higher requirement for the power system coordination and operation abili? ties. This paper proposed a four-stage intelligent optimization and control algorithm for a bidirectional Integrated Electric Vehicle Charging Station（IEVCS）equipped with photovoltaic generation and battery storage and integrated with a commercial building. It aimed at maximally reducing the customer satisfaction-involved operational cost con? sidering the potential uncertainties，while guaranteeing the balance of real-time supply and demand by adjusting the optimally scheduled charging/discharging of PEVs and battery storage，grid supply，and deferrable load. This paper analyzed the role of each stage in the algorithm and verified the necessity of each stage to provide power supply more resilience and redundancy facing unpredictable conditions.