Abstract:This paper proposed a new differential braking without close-loop control of braking pressure.The expected yaw rate to correct vehicle trajectory was determined with a reference 2-DOF vehicle model and driver model.A slip model algorithm was adopted for the close-loop control of yaw rate to compute the additional yaw moment.A braking strategy based on balanced longitudinal slip rate was presented, which improves the lateral stability of vehicle by limiting the max absolute longitudinal slip of wheels.A fuzzy controller was developed for the servo control of braking pressure.Experiments were done on hardware in loop (HIL) simulation platform based on Carsim and Labview RT.The results have shown that the presented method can effectively avoid lane departure accidents and work robustly under various operation conditions, and meanwhile, the lateral stability is maintained.

Abstract:Based on scaling and nonlinear-fitting methods, the material properties of the 3-year old pediatric cervical spine were acquired． A specific scaling method for the mechanical properties of the pediatric cervical ligaments was proposed, and the C4-C5 cervical segment finite element model for the 3-year old child was developed with accurate geometries and anatomical structures and validated under quasi-static and dynamic tensile loading.It was indicated that the simulation responses were consistent with those of experiments, with an quasi-static tensile stiffness of 211.8 N/mm, a dynamic tensile ultimate failure force of 759.9 N and an ultimate failure displacement of 5.083 mm in simulations.In addition, the force-displacement curve in the dynamic tensile simulation was also similar to that of the experiment.It can be concluded that this model is able to reflect the quasi-static and dynamic tensile mechanical properties of 3-year old pediatric C4-C5 cervical segment with higher biofidelity.

Abstract:In order to address the deficiency of vehicle plane stability region, according to the nonlinear vehicle dynamic model, a method of estimating vehicle spatial stability region was proposed.A 3DOF bus model with Pacejka Magic Formula tire model was deduced and verified by comparing vehicle tests.Based on the Jacobian matrix of the dynamic system, the stability of the vehicle system was discussed with Hurwitz criterion.In addition, by establishing a generalized function for bus system, the full loaded vehicle’s spatial stability region in 20 m/s was given on the basis of Lyapunov theory and vehicle system characteristics.A vehicle test in the same condition has shown that the calculated stability region defined by Lyapunov and system stability theorem has a good effect on characterized vehicle stability.It will be a valuable reference for vehicle stability evaluation and control.

Abstract:In order to improve the shift quality of electric vehicles equipped with combined clutch planetary transmission with two gears, a dynamic model of shift process was established.Longitudinal jerk and friction work were chosen as the comprehensive control targets by considering the changes of the motor torque and the load torque.The linear quadratic optimal control model of combined clutch friction torque was built to realize the optimal control trajectory of clutch oil pressure.Compared with the optimal control under different throttle openings and road slopes, the simulation results have shown that the optimal trajectory can effectively improve the shift quality and it is more sensitive to the changes of the motor torque than that of the load torque.

Abstract:A new control strategy was proposed by integrating active front steering and electro-hydraulic braking in distributed electric drive vehicles to ensure vehicle active safety by taking into account braking energy recuperation.The AFS controller was synthesized by means of sliding mode control.The wheel slip controller was designed with a hierarchical control structure.In the upper layer, sliding mode extremum-seeking algorithm was adopted to obtain the desired braking torque, and a dynamic control allocator considering different actuators bandwidths was employed to determine the optimal split between the electric and friction brake torque in the middle layer.In the lower layer, a hybrid actuator system consisting of the hydraulic brake and the electrical motor was designed on the basis of actuator position and rate constraints.The wheel slip control law was modified by introducing the road wheel angle factor considering the strongly coupled dynamics of steering and braking systems when braking-in-turn.Simulation results obtained with a 7-DoF vehicle model in MATLAB/Simulink environment have shown that the control strategy can significantly enhance vehicle directional stability and ensure braking energy recovery in split-μ straight-line braking, and can better track ideal yaw rate with vehicle lateral stability improvement when cornering.

Abstract:In order to improve the control precision of the Stewart platform with 6-DOF, the methods of mechanical analysis and the rotation matrix were adopted to establish the vibration platform and the Adams virtual prototype model to obtain the velocity characteristics and the acceleration characteristics.Based on the model, vibration simulation was processed under the transient motivation, and the displacement, velocity and acceleration of the upper platform were tested.The results have shown that the response of the upper platform is small and the biggest displacement appears at 0.7s and the response can be stable quickly and the first-order natural frequency is small; the platform has good low frequency characteristics and has stable response in a wide range of frequencies.

Abstract:The signal decomposition is translated into optimization problem in the adaptive and sparsest time-frequency analysis (ASTFA) method, and the signal can be decomposed adaptively in the optimization.In order to research the ASTFA decomposition capability, based on the evaluation index of decomposition capacity (EIDC), this paper studied the effect of amplitude ratio, the frequency ratio and initial phase difference by using the decomposition model with the double harmonic component synthetic signal.And then, the ASTFA was compared with the Empirical Mode Decomposition (EMD) and Local Characteristic-scale Decomposition (LCD).The results show that the decomposition capacity of the ASTFA is not influenced by the amplitude ratio or the initial phase difference, and the decomposed ultimate frequency ratio is larger.The decomposition capacity of the ASTFA method has the obvious superiority.

Abstract:According to the process with no drive, data with no carrier and other issues in the rapid design process of complex mechanical products, a new multiplatform rapid design method of products was put forward based on the consistency model of product information and the whole design process.This paper studied the top-down parametric modeling theory based on the skeleton model deeply, and elaborated on the seamless integration technology of multiplatform software, including specification calculation, optimization analysis, parametric model driving, storage of design data and planning method of data model.The rapid product design software architecture was constructed on the basis of the above research.At last, a rapid optimization and design platform of tower crane was developed on the basis of this method, and one tower design example was completed whose design circle was shortened greatly and lightweight effect was obvious.The rationality and practicability of the rapid design method proposed was also demonstrated.

Abstract:The tooth profile has significant effect on the engagement performance of harmonic drive (HD).In order to improve the engagement quality of HD, double-circular-arc and common tangent tooth profile (DCTP) as the tooth profile of flexspline (FS) were used, the conjugate existent domain (CED) and the conjugate tooth profile were established in Modified Kinematic Method, and the Least-squares fitting approach was adopted to fit it.The backlash, contact ratio, assembly state and relative movement trail were calculated to analyze the meshing performance of HD with a double-circular-arc and common tangent tooth profile.The results have shown that the tooth profile of the FS and the circular spline (CS) used with the DCTP remain continuous engagement, and the engagement point is changed continuously.Moreover, the double-engagement phenomenon is found, the theory conjugate arc length is 109.3mm, and the contact ratio reaches 69.03; compared with the harmonic drive with traditional involute tooth profile, the high engagement performance of harmonic drive can be obtained with the double-circular-arc and common tangent tooth profile.What's more, preferably selecting the coefficient of radial displacement is an important way to eliminate the interference of HD.

Abstract:A test was conducted on a liquefied natural gas (LNG) turbocharged engine in the transient process of low-speed working condition.By secondary treating the measured transient cylinder pressure curve, various combustion state parameters were obtained.On this basis, the internal relation among these transient combustion characteristic parameters and the effect of these parameters on LNG engine performances were analyzed.The results have shown that the variation range of 50% of the burnt point with the cycle number is about 5 oCA, and its fluctuation is mainly caused by the change of the combustion starting point.The peak values of 50% of the burnt point correspond to those of the combustion starting point, and so do the valley values.The peak values of 50% of the burnt point correspond to the valley values of maximum pressure rise rate and maximum cylinder pressure, whereas the opposite is true.The variation range of 10%~90% of the combustion duration is 30~45 oCA, and the rise of combustion duration becomes one of the main reasons for the decline of LNG engine IMEP (indicated mean effective pressure) and NMEP (net mean effective pressure).The fluctuations of combustion characteristic parameters are mainly caused by the instability of the combustion start point.To precisely control the combustion start point becomes an effective way to ensure that LNG engine has good transient performances at low speed and high intake pressure working condition.

Abstract:To solve the problem of how the degree of hydraulic parameters influences hydraulically interconnected suspension response, a hydraulically interconnected suspension roll frequency domain model was set up by using the Matlab.Bounce and roll acceleration output spectral densities were obtained and compared with the traditional suspension,and the results were analyzed.By applying the method of local sensitivity analysis called Morris, the influence degree of hydraulic parameters on bounce response and roll response was obtained.The results indicate that, because the liquid flows in and out of the accumulator, the accumulator and the valves connected to it have a great impact on the roll vibration model, and the valves connected to the hydraulic chambers have a great impact on the bounce vibration model.This paper provides a theoretical basis for suspension optimization.

Abstract:Based on the dynamic equations of underwater structures, the modal parameters under shock were identified with Hilbert-Huang Transform (HHT).The method combines the advantages of HHT for nonlinear and non-stationary signal, and the band-pass filters designed can select the cut-off frequency automatically, which can accurately obtain each modal response.Then, it can identify the structural natural frequencies and dampings with only one measured data in proper place.Finally, the accuracy and the validity of the method were verified on the basis of numerical simulation experiments, which identify the structural natural frequencies and dampings with one node response.It offers a practical method for the structural identification of modal parameters of underwater shock environment.

Abstract:As the switches must be turned on and off simultaneously in the proposed multi-input step-up converter based on switched-capacitor network, it is difficult to realize the independent control of each input source.Therefore, some changes were made for the structure of the switched-capacitor network, and research was done with an interleaving control.Firstly, the principle of operation and the performance of the double-input converter based on interleaving control were analyzed.And then the topology of the converter with n-input ports was presented by topology deduction.At last, simulation and experimental research was done.The results have shown that the proposed converter has a high voltage gain and allows all switches not to be turned on and off simultaneously with different duty-cycles, which realizes the independent control of each input source, and has more advantages in the field of new energy.

Abstract:A new photovoltaic array simulator was studied and designed on the basis of a Buck DC converter and the current feedback fuzzy control theory.The output voltage of the Buck converter was measured and used to calculate the current of photovoltaic array engineering mathematics model used as the input reference current of the fuzzy controller.The difference of the reference current and the real-time feedback current of the Buck converter and its rate of change were regarded as two input variables of the fuzzy controller, and then, the duty cycle of the electronic power switch was adjusted with closed-loop fuzzy algorithm to make the output voltage and the current of the simulator work at the anticipant point of the photovoltaic array on the V-I characteristic curve and realize the simulation of photovoltaic properties.A fuzzy controller with TMS320F2812CPU and a triangular fuzzy membership function was used and the domain of the input and output variables limited to ［-3 3］ contained 49 fuzzy rules.Simulation and experiment results have shown that the fuzzy control simulator can not only accurately simulate the static output characteristics of the photovoltaic cell, but can also rapidly realize the dynamic characteristics when the load or the external environment changes, and the approximate error is under 3.6%, the overshoot under 3.5%, the ripple coefficient under 3% and the tracking time about 0.3s.The fuzzy control simulator can work well as PV array experiment equipment for the research and development of photovoltaic systems.

Abstract:Based on cloud computing, a smart grid load forecasting platform architecture was presented, and the key technology of cloud computing, the cloud architecture of load forecasting, load forecasting services of cloud platform, etc were expounded deeply.We used Hadoop cloud computing technology to simulate resource scheduling and the calculation of load forecasting of cloud computing, which verified that load forecasting mechanism on the basis of the electric power private cloud was much more superior.At the same time, we introduced multi-dimensional and multi-level coordination and optimization mechanism in cloud platform load forecasting services to revise, coordinate and optimize the original forecast results, which significantly improved the level of the smart grid load forecasting based on cloud platform.The platform framework has provided wide thinking and powerful technical support for smart grid load forecasting.

Abstract:A 10 GHz low phase noise spread spectrum clock generator(SSCG) based on a fractional PLL in a 55 nm CMOS process was developed.The clock generator adopts a LC tank voltage-controlled oscillator (VCO) with switched capacitors array to obtain the wide-band frequency range and low gain, and the multi-stage noise shaping(MASH) modulating technology was utilized to shape and degrade in-band phase noise.The SSCG changes the division ratio with triangular modulation to achieve the goal of 5 000×10-6 spread spectrum clock.The measurements show that the clock generator operates at a 10 GHz, the peak reduction of electromagnetic interference (EMI) is 16.46 dB and the phase noise is -106.93 dBc/Hz@1 MHz in Spread Spectrum Clocking (SSC) Mode.The chip core area is less than 0.28 mm2 and the core power consumption is 17.4 mW at a supply of 1.2 V．

Abstract:This paper designed a NMOS ESD protection circuit with low trigger voltage (trigger voltage ≤10 V) and high ESD robustness (HBM ESD level≥4 kV).It raises the bias voltage of both the gate and the substrate of the main discharge element to an appropriate extent by designing a gate-coupled RC-network with voltage-clamping function.This not only provides a stronger discharge capacity and lower trigger voltage but also maintains a high secondary breakdown current.In this case, the ESD robustness of the MOS protection structure in CMOS deep submicron circuit is strengthened.The design is taped out in CSMC HJ018 process, and tested through TLP platform, which shows the trigger voltage is lower than 10 V and the secondary breakdown current is 3.5 A.

Abstract:A high precision switched current mirror circuit working in very weak current was presented.A method,which can automatically adjust the gate source voltage for mismatch compensation of the image MOSFET’ was adopted, and the compensation for the output error caused by the physical parameter mismatch could be realized.According to the design of the reconfigurable analog unit, the dual phase multiple output current mirror and mismatch compensation circuit were put forward, and an integrated design of timing and the programmable switch was also discussed.The produced error of the proposed design is less than 1% for the 20% mismatch, and the current range is 1 nA~1 μA.This circuit can be used in CMOS single poly process.Simulation results were presented to verify the theoretical design.

Abstract:Non-continuous orthogonal frequency division multiplexing (NC_OFDM) has large sidelobe power and high peak-to-average power ratio (PAPR).In this paper, an improved algorithm with Fountain coding was proposed, in which the sidelobe interference in NC-OFDM system and high peak to average ratio were both taken into consideration in the joint optimization algorithm under the circumstance of cognitive radio system.Fountain multi-choice sequence algorithm, by the ideal of Fountain coding and sequence mapping, was adopted for sidelobe suppression and PAPR reduction.The simulation results show that the improved algorithm can significantly reduce the band interference to licensed user (LUs) and make the system PAPR less than target PAPR, so as to solve the problem of NC_OFDM signal distortion caused by power amplifier and eventually enhance the performance of the bit error rate effectively.

Abstract:Based on equal runlength code and IFDR, a new coding method (called ERFDR) was proposed.Firstly, the proposed method can not only encode both 0 and 1 runs for a test set simultaneously, but also can use shorter code if the adjacent runlengths are equal.Therefore, the compression ratio can be further improved.This paper also put forward a new filling algorithm for a test set with don't care bits, which can enhance the compression efficiency of the proposed method.Experimental results show that the proposed method can obtain a higher compression rate compared with FDR, EFDR, IFDR and ERLC codes.The test cost can be reduced effectively.

Abstract:A short text algorithm based on semantic and syntax by analyzing the characteristics of Chinese short text was proposed.The algorithm combines semantic similarity with the similarity of sentence syntax in Chinese short text, that is to say, to calculate the similarity of short text with the same syntax structure and consider the contribution with sentence words order to similarity.The experiments show that the proposed algorithm is closer to people's judgment and gets a better precision rate and recall rate in the aspect of Chinese short text similarity calculation results.

Abstract:In order to solve the problem of the high accuracy delineation of biological target volume (BTV) for the radiotherapy of head and neck cancer, a random walk method was proposed by using PET (positron emission computed tomography) image features of tumors.Firstly, the selected region of interest (ROI) was segmented into the primary tumor (labeled as foreground seeds), normal tissue (labeled as background seeds) and pending region by three-dimensional adaptive region growing and morphological dilation based on PET SUV images.Secondly, due to the differences of contrast texture feature of head and neck tumor and surrounding normal tissues in PET images, the contrast texture feature was incorporated into the weights of random walk(RW) to further improve the accuracy of tumor segmentation results.Clinical PET image segmentations of head and neck cancer have shown that the improved RW is 9.34 times faster than the traditional RW on average.And the similarity is increased by 32.5% on average if the gross tumor volume delineated by clinicians is considered as the ground truth (P<0.05).The proposed method is an efficient and accurate method for the delineation of the BTV corresponding to head and neck tumors.

Abstract:Wideband spectrum sensing methods based on information theory criterion (ITC) solve the problem of noise uncertainty, so it has been extensively studied.But deducing the sensing decision rule using the information theory needs to assume that the received data vectors are statistical independent, and that the noise is Gaussian white noise.Meanwhile, this kind of methods possesses high implementation complexity.To overcome these limitations, this paper presented a new wideband blind spectrum sensing method based on the rank criterion.This proposed method firstly divides the sample covariance matrix of received signal into the “ideal” matrix having rank of q and the “disturbance” matrix, the rank criterion function is then used to search the optimal q value, which is used to determine the numbers and the locations of the occupied channels.The new method requires no a priori knowledge about the noise power, the statistical characteristics of the wireless channel and the primary user signal.Compared with the existing ITC based wideband sensing methods, the proposed method has a more concise decision expression and then has lower computational complexity.In addition, the new method shows excellent performance in colored noise sensing scenarios.Simulation results verified the effectiveness of the proposed method.