A traction control system for four wheel drive vehicle is presented in this paper. According to the project of hardware and control strategy given, a control software is designed. The mathematical models of accelerating process are established and control systems are also designed. A computer simulation is made on low-μ road, split-μ road and loose sand. The results indicate that the traction control system can prevent the wheel excess spinning on the three above roads effectively.

Control characteristics of critical knock of S.I.engine have been experimentally investigated,and optimal ignition advanced angle surface of engine controlled by a knock control unit has been obtained.Knock identification told of difference in knock intensity from cylinder to cylinder.Power output and fuel economy of engine under control of knock control unit were tested and results prove that performances can be improved when engine approaches critical knock conditions.It is found that adjustment inertia exists in adjusting process of the knock control system and its effect was discussed.

Effects of excess air ratio φsub>a and ignition advanced angle θ on CO,HC and NO_x emissions from a 125 mL gasoline and ethanol engine with electronic fuel injection were studied experimentally.It is proved that ethanol engine emits less NO_x than equivalent gasoline engine.Relatively optimal ranges of φsub>a and θ to lower emissions from ethanol engine were proposed which are useful to the parameter matching of ethanol engine.

In view of the effect of multiple circular holes on the strength and stiffness of the element matrix instillation board in multi point forming press,plates with dense circular holes were analysed using ANSYS software,the stress and deformation distributions in boards with different numbers of holes are obtained.The stress concentration near hole is investigated in detail by submodel technique.The calculated results of stresses distribution presented in the paper are very useful to the design of multi point forming press.

Based on the principle of acoustic emission(AE)detection, a mathematical model between AE parameters and cracking stress from the relation of the signal peak voltage and emission energy during the deformation of material is established.A general expression between the total counts and counting rate is developed.During the tensile test,with the AE detecting system developed,it is found that the defects in ZG25 steel,such as gas pore,slag inclusion and microcrack, show different AE characteristics.Thus,AE as a non destructive method is practically useful for metallic materials.

The article applies system engineering theory,constructs the system composing model of auto parts industry,posts the correlation between subsystems.The article makes in depth research on R&D subsystem,manufacture subsystem,marketing subsystem,organization subsystem of auto parts,constructs the system engineering frame of optimization of R&D,manufacture,marketing,organization,and posts the compositing factors,correlation and running rules of these subsystems.

Pedestrian vehicle collisions have been reconstructed by a computer simulation model to analyze the influence of vehicle froepart parameters on the relative collision velocity between pedestrian head and bonnet top surface.Results show that bonnet leading edge height has a significant effect(α=0.01)on relative collision velocity between pedestrian head and bonnet top as well as that of interaction between bumper central height and bonnet leading edge height(α=0.05),but bumper central height,bumper height between upper reference line and lower reference line,bonnet slope angle as well as their interaction only has little effect.

Thermal analysis has been carried out on piston of a micro engine with displacement of 0.33 ml by 3 D finite element method(FEM).Related experiments were conducted by IR thermography and fusible alloy plugs.Precision of mathematical model was improved by inverse process from experimental data.Calculated results show that because of structure of exhaust system,temperature field and thermal deformation of piston appear minute axial asymmetry.Failure may happen in ball joint which suffers high temperature and stress.Axial temperature and deformation of piston shirt are in shape of exponential curve along piston wall.High speed cooling airflows and large engine surface area to volume ratio decrease both engine thermal load and efficiency.Presented methodology is universally suitable for micro engines with displacement less than 1 ml.

This paper describes a method of pressure control using PCM for hydraulic system.Combining three changeable reducers and electromagnetic valves properly,eight levels pressure control can be carried out for hydraulic system.And the structure is simple,reliable,low cost.By introducing the design and application of a test equipment,the paper shows that the technology of noncontinuous control for hydraulic system is advanced and useful in industry in the future.

Object-oriented modeling provides a mechanism for representing information by using models organized around real-world objects and concepts. Basic construct of the mechanism is a object, which combines both the data structure and its behavior into a entity. The object has many characteristics, just like the unique identifier, generalization and inheritance, classification and aggregation. But these are not enough to modeling product. The data of product are produced gradually, so that you can not define the object completely. When the design process is ended, the product object is created. In order to cope with this problem, the paper expands the definition of object, partitions the object into dynamic models according to the evolution of object. It also presents the object views of dynamic model to describe the static characteristics of dynamic model of object. Based on the two concepts, the paper discusses the application in product modeling.

We present genetic algorithm with an incomplete representation and apply it to the Job-shop scheduling problems.The important characteristic lies in that the number of genes is less than the number of operations.The rest of the schedule is completed by a simple heuristic rule.The results imply that the nearly best solution can be found in a national time interval by incomplete genes presentation.And incomplete genes presentation make the genetic algorithms more efficient by canceling high redundancy at the tail of the chromosome and little significance of rear genes.

In the paper, fault information database of flexible manufacturing system(FMS)is set up,fault analysis is carried out for main cells of the primary system of state key laboratory for FMS technology,weak link and fault mode monitored of CH-85 FMS is ascertained,to which monitoring and maintenance should be mainly made.

Based on the analysis of the globoidal indexing cam,the sphere conical roller globoidal indexing cam mechanism was presented.Pressure angle of conical roller globoidal indexing cam mechanism were analyzed and calculated in detail.This makes the theory basis for advanced study on the mechanism.

The 3 dimentional FEM code DEFORM was successively applied to simulate cold closed die forging of bevel gears and the cold forging technology was studied experimentally on hydraulic die shelf of closed die forging.The results show that the technology design of cold closed-die forging bevel gear is reasonable,the die cavity design is accurate and numerical simulation is effective.

A beamforming approach based on third order cyclic statistics is presented in this paper.And a new beam space time block coding scheme with this approach by using dual antenna arrays at base station and multi antenna elements at mobile terminal is proposed.This scheme can improve mobile terminal receiving performance and increase the communication capacity for entire wireless communication system.Simulation results show the effectiveness of this scheme.

A main disadvantage of multicarrier modulation is that it exhibits a high peak to average power ratio(PAPR). It is presented in this paper that with Golay code as spread code for MC-CDMA system,PARA can be reduced.The analysis and comparison of the PARA complementary cumulative distribution function(CCDF)of MC-CDMA signal by using Golay code and Walsh-Hadmard code respectively as spread code,and the performances of two systems in multipath fading channel are given.Simulation results show that there is 3dB reduction in the uplink PAPR of MC-CDMA system using Golay code and no performance lost compared to the system using WH code.

A DC-DC buck converter controlled by naturally sampled, constant-frequency PWM is operated in continuous conduction mode. Its behavior under different circuit parameters is deeply studied in this paper, especially chaotic behavior and corresponding output performance. The transforming pattern of the system behavior from stable state to chaotic state is discovered via a cascade of period-doubling bifurcations of the output voltage in the bifurcation diagram and a cascade of periodic orbits in the u-i phase space with filter capacitor as a variational parameter. The fact that some special values of the circuit parameters may lead to chaotic behavior is validated. Performances of the output ripples from stable state to chaotic state are also analyzed in time domain and frequency domain respectively.According to the developing trend of spectral characteristics from period 1 to chaotic state,some important conclusions which will become a helpful tool for optimization design of DC-DC converter are given.

A new kind of BP algorithm-LMBP that converges very fast is proposed in this paper by using Levenberg Marquardt optimization method and standard BP algorithm.The experimental results prove that LMBP converges very rapidly and has good stability property compared with that of the standard BP algorithm and other improved ones.LMBP algorithm is suitable for the case with high demands of on-line computation,e.g.on-line measurement.But when the size of neural network increases, it needs enormous calculation and large computer memory space.

A multi model fuzzy controller using the idea of partition running space for open loop and unstable inverted pendulum is presented in this paper.The swing-up and balancing control problems are discussed.Simulation results by using this proposed controller in wide range parameter and environment variation and comparison with those derived from LQR method is given.These results show that this multi-model fuzzy control algorithm can realize robust stable swing up and balancing control.

An off line emulate experiment environment was set up to emulate the CAN communication in local area network of multiple energy sources power assembly experiment platform of HEV.The nodes in network may transmit information each other in the experiment environment.The emulate system realized information conversion of bus protocol between CAN and J1939.It is composed of three computers which simulate HCU and other ECUs to transmit messages each other.This emulate system can adjust parameters of communication dynamically and analyze content of messages real time.It has been used to test motor controller's communication capability in HEV.The result indicated that this emulate system can run stably,display intuitively and analyze correctly.So it can provide technology support and resolvent for CAN communication in HEV.

An algorithm for attention selection of active machine vision system was proposed.This algorithm employs the pyramidal representation to resolve the problem of calculation amount,it also employs the sequential templet and saliency map to combine the upper layer information, and integrates both the data driven and model driven mechanisms.We had done a lot of tracing experiments based on our attention algorithm which include monocular and binocular tracing for human being and physical objects under complex scene on the experiment platform.The experiment results prove the effectiveness and robust of this algorithm.

In order to estimate the Hurst parameters of the 1/ƒ-type fractal signal, the wavelet transformation is used to deal with the discrete fractal Gaussian noise.Using the least square algorithm,a method for estimating the Hurst parameters is developed.A numerical example is given to illustrate the effect of the data length on the computing accuracy of the present approach.

In order to fulfill dynamic on-line volume-weight measurement,in the same time to implement closed loop control,and obtain feedback information of both length and weight,the design of a quasi dynamic volume-weight measuring system is given in this paper,which can simplify dynamic weight measuring problems.

An edible film based on potato starch was studied,which can be instantly soluted in hot water. For the film,the carboxymethylcellulose as the intensifier was added in the solution and the epihydrin was used as the cross link agent.The results of optimized experiments that summarized by variance analysis show that the most remarkable factor influencing the tensile strength and elongation is the potato starch density while the most evident factor affecting the instant solute ratio in the hot water is the dry temperature of the film.

Relationships between pH and TVB-N and storing date of chilled beef were studied.Appraisement equations based on regression function were carried out where a fuzzy appraisement was applied.Freshness of beef was appraised using pH and TVB-N.Finally,the appraisements on freshness of beef based on image process and neural network were investigated.The research shows that pH and TVB-N values can be considered as appraising targets.As pH and TVB-N are used to appraise freshness of beef,the obtained correctness rate is higher than that when only one of them is utilized.By using image analysis for appraisement on freshness of beef,the obtained correctness rate is not only the highest among the used methods.But a complicated chemical experiment is not necessary.The method is rapid and convenient for appraisal of freshness of beef.

According to the formation and influencing factors of the high-tech enterprise performance,an index system of high-tech enterprise performance assessment is established and a typical high-tech enterprise is selected to validate it.The index system and appraisal in this paper can respose facts of high-tech enterprises,which have a significance on performance management of high-tech enterprises.

Gait analysis is a basis of robot research. A reasonable design of gait and posture should be done so as to make a robot being of a steady walk. The gait and the posture of men, quadrupedal animals, snakes and caterpillars and their differences were reviewed. The gait strategies of the walking robot in varied walking models were described. The developments of research on the animal's gait and walking robot were analyzed.

A review and description are made of bascic principles,imaging pattern of a scanning probe microscope and its application in ultraprecision machining. This paper gives an overview of SPM application in microfabrication and photofabrication,and indicates that the research of nanometer sized machining mechanism will rely on SPM composition and multi functions. None but the integration of processing and measurement is realized,machining method and optional selection of technological parameter are right evaluated,advancing the development in ultraprecision machining.