Automobile anti lock braking system control based on a least squares support vector machine

Using the referenced slip rate and angle acceleration of the wheel as input vectors and the braking pressure as an output vector, an automobile anti lock braking system (ABS) controller based on a least squares support vector machine (LS SVM) was designed. Training the LS SVM controller using the supporting vector, the parameter of the controller was calculated. An anti lock braking system was designed that includes an input layer, a control layer, and an output layer. Using wheel speed as an input, the braking pressure of each wheel was calculated. The pulse width modulation (PWM) method was used to control the braking pressure, and thereby to bring ABS control. An automotive ABS test and control system was constructed. Road tests under different conditions were completed according to international standards. Test results show that an anti lock braking control method based on LS SVM has good braking stability and adaptability. It is an effective new ABS control method.     

Optimization of Helix Intake Port Based on Numerical Simulation

With numerical simulation, an analysis is done on the three-dimension air flow in the helix intake port of a diesel engine. The anthors acquire the distribution of characteristic parameters of air in the port, such as velocity, pressure, turbulence kinetic energy, as well as the flow coefficient and rotate moment around the erect axes at the outlet. The results of simulation indicate that the negotiability of the port is very good while the ability of forming eddy can be enhanced, so several improve measures have been put forward. Comparing with simulation results of these measures, it finds out that the method of combining increase the distance between the definition curve of volute cavity and central line of valve protruding support as well as increase the eddy shell angle can obviously enhance the ability of forming eddy, which is an efficient and rational method.     

Control strategy of regenerative braking for hybrid electric vehicle based on engine braking

Focusing on a continuously variable transmission(CVT) hybrid electric vehicle with integrate starter generator(ISG), modeling and simulating of engine braking was conducted. An optical control strategy of regenerative braking was put forward. When there is no regenerative braking, engine brake force can be used effectively by changing the CVT ratio to reduce the braking force requirements for wheel brakes based on the calculated results of engine braking. When there is regenerative braking, the braking priority sequence is generator braking, engine braking, and finally frictional braking. A forward simulation model for regenerative braking system of hybrid electric vehicle was built. The simulation and analysis under typical driving cycles was conducted. The result shows the control strategy and the models are reasonable and feasible.     

Test Bench of Air Braking System for Vehicles

The stability of the brake system is a key factor for the vehicle safety.It is important for the air braking system's stability to shorten the time lag between the front brake and the rear brake,the reasonable disposal of the air pipeline and the optimization of the braking system design.A test bench is developed to test the performance of the air braking system,which is mainly made of pressure sensors,signal amplifiers,data acquisition system,computer,pressing air resource and so on.Based on this test bench,the reaction time of the system while braking and abandoning brake can be measured.Using this test bench,the performances of the air braking system of a certain commercial vehicle is detected.Compared with the actual road test,it can save the cost and the time for experiment largely.     

Modeling and simulating the vehicle riding dynamics considering gradient effects

Considering road characteristic parameters such as lateral gradient, longitudinal gradient and synthetic gradient, and based on 15 degrees of freedom (DOF) vehicle dynamics model, the authors develop the vehicle dynamics model, tire vertical load variation model and whole vehicle riding dynamics simulation model combined with steering system, braking system, power train system, wheel and suspension models. The situations are compared under different lateral, longitudinal, synthetic gradient and vehicle speed. The simulation results show that yaw rate maintains invariably to longitudinal gradient variation, but decreases gradually with the increase of lateral and synthetic gradient. The margin of fluctuation and peak value increase with the increase of vehicle speed under the same gradient; front wheel sideslip angle maintains invariably to longitudinal and synthetic gradient variation, yet increases with the increase of lateral gradient; the roll rate decreases and then increases with the increase of lateral and synthetic gradient, and the margin of fluctuation and peak value increase with the vehicle speed increase under the same longitudinal gradient.     

Parameter design and simulation for animproved direct current side active power filter

Considering the characteristics of the dc side series active power filter (APF) that the output voltage cannot be adjusted and the control circuit is complex , an improved single phase dc series APF topology is proposed. The improvement of the new circuit topology and fundamental working principle are analyzed. Following the circuit power factor pre regulator principle, the designing method for the main circuit parameters is given. The voltage ring and the current ring are designed by using the zero pole method. The main circuit power switch is controlled with the same frequencies, while the control circuit was simplified further. Compared with the paralleled APF, the main circuit of topology structure is simplified and the number of the active switches is reduced, which show low input current harmonics, high power factor, large voltage output adjustment range and low cost. The simulation results prove that the proposed topology is correct and reliable.     

Study of Lightning Impulse Breakdown Voltage Correction of PositiveRod-Plate Short Air Gaps on Altitude

The air pressure of the high altitude condition in the artificial climate chamber is simulated, and the laboratory investigation of positive rod plate lightning impulse discharge performance were carried out on the short air gaps of 200 mm, 300 mm and 450 mm according to the test method demanded in IEC 60.1. Based the tested results, it is put forward that the positive lightning impulse breakdown voltage of a short air gap at the air pressure of the high altitude district is a power function of the air pressure with a special index less than 1, which indicates that the effect of the air pressure on the breakdown voltage decreases by 8.7% with the increase of the altitude by 1 kilometer. According to the theoretical analysis, it is proposed that the air pressure suggests the comprehensive changes of the basic atmospheric parameters of the temperature, the reltive air density and the absolute humidity, thus it could be used as the characteristic variable which expresses the effect of the absolute humidity, thus it could be used as the characteristic variable which expresses the effect of the atmospheric condition on the breakdown voltage of an air gap.     

Dealing with Thermal Exchange in Temperature Field Simulation in Low Pressure Die-casting Process

The main effort is to develop numerical simulation software of low pressure die casting on Windows platform in Personal Computer, based on the production of aluminum wheel in Die cast wheel manufacture Co. Ltd.. The heat conduction calculation is the basis of solidification simulation. A 3 dimentional model including the refrigeration medium block is set up based on the study of boundary heat exchange. Various calculation method is analyzed for different types of boundary element. A comprehensive calculation model is set up according to practically manipulable parameters in production.     

抗旱保水剂在甘薯上的应用效果

为探讨惠安旱地农业抗旱措施,引进了珠海得米化工有限公司生产的抗旱保水剂,在花生与甘薯轮作试验成功的基础上,又继续在甘薯上进行试验。结果表明,施用抗旱保水剂能与生物有机肥一样促进甘薯生长,抗旱保水剂增加产量5000.0kg/hm2,生物有机肥增加产量5111.1kg/hm2;施用保水剂60kg/hm2增产增收效果最好,增加产出3000元/hm2,投入产出比1∶1.67。     

Fuzzy Control and Simulation of Regulating System for Permanent Magnet Synchronous Motor

This paper researches the fuzzy control and simulation of regulating system for PMSM in electrical vehicle. The mathematics model is set up.The PMSM,the PMSM measures demux, dq to abc converter and the three phrase PWM converter models are set up in MATLAB/ Simulink. The fuzzy controller is designed with two dimension fuzzy design method, and take E and EC as input variable, U is the output variable. According to the controller and models, the fuzzy control model of regulating system for PMSM is created in matlab/simulink. At last, to test the accuracy of the control method with the simulation result.     

Simulation analysis on braking system of hybrid vehicle with ISG

A hydraulic braking system of the hybrid vehicle is designed based on braking force distribution and brake pressure coordination control strategy of integrated startor and generator(ISG) hybrid electric vehicle(HEV). Simulation model of hydraulic braking system has been established using AMESim software platform. Dynamic performance simulation and analysis to the key components and systems are performed. The results verify the correctness and feasibility of system program and provide evidence for designing and optimizing of HEV braking system.     

Experimental Analysis on Power Consumption of Chilled Water Pump by Constant Pressure Difference Method with Bypass Valve

The power consumption of frequency conversion chilled water pump of an office building regulated by constant pressure difference method with bypass valve is studied experimentally. A model of power consumption of chilled water pump is proposed. The effects of pressure difference set point of bypass valve on instantaneous and annual power consumption of chilled water pump are analyzed. The simulation results are validated experimentally, which shows that there is a maximum water flow rate which increases with the increase of the pressure difference set point of bypass valve at equilibrium state. There are three pressure operation regions of the bypass valve: under pressure region, constant pressure region and over pressure region. The power consumption of frequency conversion chilled water pump is affected by the pressure difference set point of bypass valve significantly, and it would be minimized as the pressure difference set point of bypass valve is equal to the pressure difference between supply water and return water of the farthest user.     

Multi-field coupling effect on coalbed methane seepage characteristics and numerical simulation

This paper studies the seepage of coal samples under the influence of each single factor, the axial stress, confining pressure, gas pressure, and temperature by experiments. It uses Ansys12.0 to numerically simulate the law of coalbed methane seepage, coal deformation, pore pressure, the distribution of flow field under the influence of each single field and multi-field coupled. The numerical simulation show that the result of numerical simulation of gas seepage law in the coal under each single fields is basically the same as the experimental result. The curve of gas seepage and average effective stress under the condition of multi-field coupled is negative exponential relationship. Stress influenced the deformation of the specimen is greater than the seepage field. The axial stress on the deformation of the specimen is greater than confining presses The influence on the flow field by confining pressure is greater than axial stress, the influence of axial stress on the pore pressure is greater than confining pressure, pore-pressure under the action of multi-field is bigger than pro-pressure under each single field. To study the seepage law of coalbed methane, it should consider the influence of gas-solid-heat at the same time.     

Development and Investigation on Duty Valve Drived Hydraulic Brake Servo System

A duty valve drove hydraulic brake servo system of HEV(hybrid electric vehicle) power transmission test rig is studied.The brake performance depends on the responses of the pressure control.A PI controller is designed through analyzing the working characterizes of the hydraulic brake system and duty valve by using rapid control prototype(RCP) tool-dSPACE,all the model and control code are successfully download to the AutoBox,and rapid control prototype experiment shows that the benefits of developing duty valve drove hydraulic brake servo system with good performance has been achieved.     

Design Process Simulation Based On Information Dependency

A modeling method based on DSM is introduced. In circumstance of iterative task, the ways concerning about the input of data,the generation of stochastic variables and the set of the simulation clock are dipicted. While considering the learning curve of activities, the way is studied express the movable process of a single project and then list the corresponding Monte Carlo simulative block diagram .The program based of EXCEL VBA is also written. The result of a given simulative example shows that the method can simulate complex design activities and plan the project in terms of scientific basis.     

A Theoretical Study on Thermal Dynamics Model and the Dehumidification Capacity of Hybrid Desiccant Cooling System with Condensation Heat Recovery

The structure and energy conservation characteristics of hybrid desiccant cooling system with condensation heat recovery are introduced briefly. Based on the first and second law of thermodynamics, a system thermodynamic model is established and the solution process given in a diagram. The dehumidification capacity is calculated under different exergy efficiency and indoor sensible heat conditions. The calculation results show that the desiccant wheel barely can compensate for the humidity load of outdoor air under with a ventilation rate of providing fresh air once per hour; when the fresh air rate of ventilation is limited to 0.5 times per hour, however, the desiccant wheel possess sufficient capacity under relatively large wheel exergy efficiency and high sensible heat load.     

不同送风方式下樱桃压差预冷的数值模拟

预冷时间对樱桃的贮藏期有着重要的影响,故合适的压差预冷方式成为预冷的研究重点。本文建立了水平送风与垂直送风的樱桃压差预冷数学模型,分析了两种不同送风方式下不同风速下包装箱内部的压力损失、预冷时间、均匀程度的变化情况。模拟结果表明:樱桃的预冷时间随送风速度的增加而减小,压力损失随风速的增加而增大,两者与送风速度的拟合关系均为幂函数;同时樱桃的不均匀度也受送风速度的影响,两者呈正相关;在送风速度6～16 m/s范围内的垂直送风的不均匀度仅为水平送风的75%左右。综合预冷时间、压力损失和均匀程度可以得到水平送风与垂直送风的最佳送风风速分别为9.3 m/s与12.7 m/s,压力损失分别为94.8 Pa与87.9 Pa,预冷时间分别为48.10 min与45.89 min,不均匀度分别为0.412与0.330。即垂直送风的预冷方式在樱桃压差预冷方面有一定的优势。     

运行参数对微型内燃机微燃烧特性影响机理分析

微型内燃机微燃烧过程对当量比和转速变化非常敏感,采用层流有限速率模型和甲醇氧化反应机理对其预混层流微燃烧过程开展仿真研究,探讨当量比和转速对微燃烧特性的影响规律及临界运行参数。在此基础上,提出采用热着火理论和化学反应动力学理论探索当量比对微燃烧特性的影响机理。结果表明仿真与实验比较吻合。当量比从0.6增加到1.1时,燃烧速率增加,压力和温度增加,压力最高值增加约1.5E+6 Pa,温度最大值增加约1 300 K,此后随当量比增加,燃烧速率减小,压力和温度减小。研究还进一步揭示了当量比影响微燃烧特性的机理: 稀燃区当量比主要通过温度变化来影响微燃烧特性,随当量比增加,燃料浓度增加,燃烧释放的总热量增加,所以温度和压力增加,燃烧速率增加;浓燃区当量比主要通过氧气量变化来影响微燃烧特性,当量比越大,氧气量越不足,基元反应速率越小,所以燃烧速率越小,温度和压力越低。转速越高,燃烧时间越短,燃烧越不充分,所以温度、压力越低。受微燃烧相对热损大、驻留时间短的特征影响,微型发动机实现完全燃烧的运行区域较窄,其实现完全燃烧的稀燃极限约0.9,最高转速约6 000 r/min。这在设计微型内燃机时值得关注。     

棉花栽培计算机模拟决策系统(COTSYS)

棉花栽培计算机模拟决策系统（简称：棉花系统）（英文名： ＣＯＴｔｏｎ ｃｕｌｔｉｖａｔｉｏｎａｌｓｉｍ ｕｌａｔｉｏｎ ａｎｄ ｄｅｃｉｓｉｏｎ－ ｍ ａｋｉｎｇ ＳＹＳｔｅｍ ， 简称ＣＯＴＳＹＳ），是在大量田间试验和生产示范信息反馈基础上，结合劳模、专家经验和模式化栽培技术，历时７年研制完成的。系统由数据库管理、模拟与分析、栽培决策、病虫害防治及经济效益分析５个子系统组成，可用于棉区棉花生产和当年栽培优化决策，制作栽培决策方案和栽培规程；进行棉区生产潜力分析，模拟预测棉花生长发育和产量的形成；进行有关参数和数据库管理，以及病虫害防治决策和经济效益分析等。系统适在特早熟、中早熟及中熟三个生态棉区应用效果良好。     

APPROXIMATION OF INVOLUTE PROFILE BY PEACH-SHAPED RING SECTION

By using the least pth min-max method, we find the best approximation of involute ptofile by peach-shaped ring section. The error of approximation is less than that of [ 1 ] and [2]. Thus we provide a new direction for dressing of a wheel for involute gear forming-grinding. In order to simplify calculation, we define the error function according to implicit equation of curve and as a result its rationalization is proved.