Multi-objective Genetic Optimization for LCLS-II X-ray FEL

The LCLS-II （linac coherent light source II） will build on the success of the world＇s most powerful X-ray laser： the LCLS （linac coherent light source）. It will add two new X-ray laser beams and room for additional new instruments, thus greatly increasing the number of experiments carried out each year. Multiple operation modes are proposed to accommodate a variety of user requirements. There are a large number of variables and objectives in the design. For each operation mode, MOGA （multi-objective genetic algorithm） is applied to optimize the machine parameters in order to minimize the jitters, energy spread, collective effects and emittance.     

Thermoelectric Behavior of Isotropically Conductive Adhesive

The paper deals with unusual use of one kind of ECA （electrically conductive adhesive）---the ICA （isotropic conductive adhesive）. The main sphere of ECA application is electronic assembly, e.g., it is bonding of semiconductor microchips on printed circuits boards. In this sphere, the ECA compete with soft solder. In spite of this fact, the author utilized of two main ECA characteristics--good electrical conductivity and excellent adhesion to material surfaces to make the fiat thermocouples. Both the design of thermocouples and the measuring device and the measuring workplace arrangement are described. The measured data of thermoelectric voltages are plotted. The thermoelectric （Seebeck＇s） coefficients were calculated from obtained dependences of thermoelectric voltage versus the temperature differences.     

Shop-Floor Controller Based on RT-Middleware Technology

Nowadays the flexible configuration of manufacturing cells becomes to an important requirement especially at small and medium sized companies. This method can make the production fast and effective at small series or frequent manufacturing changes. The shop-floor control method, presented in this paper, offers a solution for the facing problem of fast and easy reconfiguration. The hardware of the controller designed modular with software components for online configuration. This solution allows sensor integration on different levels for every part of the manufacturing cell. With unified programming language and the machine specific controllers （post-processing） the cells can be defined easily by different types of human-machine interaction. The shop-floor control architecture is implemented and validated on an Adept SCARA （selective compliance assembly robot arm） robot. The robot is driven by standalone, low-level, interchangeable, software and hardware components.     

Impact Dynamics on Granular Plate

In this paper, a theoretical and numerical study on the impact of a rubber solid on the free surface of a granular plate is presented, showing a simulation of an aircraft wheel on impact with a flexible landing surface. This physical action, when we use a theological approach, becomes a fundamental parameter to investigate wear and tear, and consequently strength to micro and macro pavements failure. The study has developed initially from a microscopic point of view and subsequently on macroscale. The effects are strictly linked with material degradation associated with damage evolution. The problem is developed by energetic approach on an elastic-plastic element using the functional energy containing two contributions, bulk and surface. The model simulates the behaviour of flexible runway pavements during the landing phase.     

Development and Impact Behaviors of FRP Guarder Belt for Side Collision of Automobiles

In automobiles, the CFRP （carbon fiber reinforced plastics） has a possibility of weight reduction in automotive structures which can contribute to improve mileage and then reduce carbon dioxide. On the other hand, the safety of collision should be also made clear in the case of employing the CFRP to automotive structures. In this paper, the CFRP guarder belt equipped in the automotive door is developed and examined by an experiment and a numerical analysis for replacing the conventional steel door guarder beam. As the experimental relation of impact load to displacement for CFRP guarder belt agreed well with that of numerical result, the numerical method developed here is quite useful for estimating impact behaviors of CFRP guarder belt.     

Numerical Study of the Mixing of Density-Stratified Fluid with a Jet

Density stratification of LNG （liquefied natural gas） is produced in a storage tank when one LNG is loaded on top of another LNG in the same tank. Mixing LNG by a jet issued from a nozzle on the tank wall is considered to a promising technique to prevent and eliminate stratification in LNG storage tanks. This study is concerned with the numerical simulation of a jet flow issued into a two-layer density-stratified fluid in a tank and the resultant mixing phenomena. The jet behavior was investigated with the laboratory-based experiment of the authors＇ previous study. A numerical method proposed by the authors is employed for the simulation. The upper and lower fluids are water and a NaCl-water solution, respectively, and the lower fluid is issued vertically upward from a nozzle on the bottom of the tank. The Reynolds number （Re） defined by the jet velocity and the nozzle diameter ranges from 95 to 2,378, and the mass concentration of the NaCl-water solution Co is set at 0.02 and 0.04. The simulation highlights the jet-induced mixing between the upper and lower fluids. It also clarifies the effects of Re and C0 on the height and horizontal spread of the jet.     

Investigation of Cutting Force by End Milling Operation

In this work, the cutting forces by end milling operation are analyzed. Therefore, the main parameters of cutting force as cutting speed, feed rate and depth of cut also are investigated in our case. The cutting force is modelled and analyzed into mathematical Wolfram simulations in order to compare the results and in the same time achieve the best solutions. Theoretical results are carried out by using the regression method that required fulfilling the critter by Fisher. The number of experiment, measurements and results of cutting force are presented in 2D as well as 3D. In order to verify the accuracy of the 2D diagram, the results for our case is used both two way such as experimental and theoretical method as well as results are compared. In other hands, these results indicate directly that the optimized parameters are capable of machining the workpiece. The obtained measurement results are compared with theoretical methods in Wolfram software.     

Development of Five-Finger Multi-DoF Myoelectric Hands with a Power Allocation Mechanism

To be used as five-fingered myoelectric hands in daily living, robotic hands must be lightweight with the size of human hands. In addition, they must possess the DoFs （degrees of freedom） and high grip force similar to those of human hands. Balancing these requirements involves a trade-off; ideal robotic hands have yet to sufficiently satisfy both requirements. Herein, a power allocation mechanism is proposed to improve the grip force without increasing the size or weight of robotic hands by using redundant DoFs during pinching motions. Additionally, this mechanism is applied to an actual five-fingered myoelectric hand, which produces seven types of motions necessary for activities of daily living and realizes a -60% improvement in fingertip force, allowing three fingers to pinch objects exceeding 1 kg.     

Localization of Small Mobile Robot by Low-Cost GPS Receiver

This article deals with a problem of the robot localization in the outdoor environment by using the GPS （global positioning system） data. In order to navigate the robot, it is necessary to transform the global position into the local map in the form of two-dimensional Cartesian coordinate system. The transformation is based on the model of the Earth-WGS 84 reference ellipsoid. The aim of this article is to experimentally evaluate a set of low-cost GPS receivers applicable as position sensors for small outdoor mobile robots. The evaluation is based on series of measurements executed in different times and places. The measured data is processed by given procedure and acquired positions are transformed into the local coordinate system. Accordingly the accuracy of the measured positions is statistically evaluated. The evaluation of used GPS receivers is done by comparison with data acquired by high-end geodetic GPS system Leica 1200, which is used as a reference GPS system.     

Design,implementation, and test of skid steering-based autonomous driving controller for a robotic vehicle with articulated suspension

This paper describes an autonomous driving control algorithm based on skid steering for a Robotic Vehicle with Articulated Suspension (RVAS). The driving control algorithm consisted of four parts: speed controller for following the desired speed, trajectory tracking controller to track the desired trajectory, longitudinal tire force distribution algorithm which determines the optimal desired longitudinal tire force and wheel torque controller which determines the wheel torque command at each wheel to keep the slip ratio below the limit value as well as to track the desired tire force. The longitudinal and vertical tire force estimators were designed for optimal tire force distribution and wheel slip control. The dynamic model of the RVAS is validated using vehicle test data. Simulation and vehicle tests were conducted in order to evaluate the proposed driving control algorithm. Based on the simulation and test results, the proposed driving controller was shown to produces satisfactory trajectory tracking performance.     

Influence of surrounding structures upon the aerodynamic and acoustic performance of the outdoor unit of a split air-conditioner

DC-inverter split air-conditioner is widely used in Chinese homes as a result of its high-efficiency and energy-saving. Recently, the researches on its outdoor unit have focused on the influence of surrounding structures upon the aerodynamic and acoustic performance, however they are only limited to the influence of a few parameters on the performance, and practical design of the unit requires more detailed parametric analysis. Three-dimensional computational fluid dynamics（CFD） and computational aerodynamic acoustics（CAA） simulation based on FLUENT solver is used to study the influence of surrounding structures upon the aforementioned properties of the unit. The flow rate and sound pressure level are predicted for different rotating speed, and agree well with the experimental results. The parametric influence of three main surrounding structures（i.e. the heat sink, the bell-mouth type shroud and the outlet grille） upon the aerodynamic performance of the unit is analyzed thoroughly. The results demonstrate that the tip vortex plays a major role in the flow fields near the blade tip and has a great effect on the flow field of the unit. The inlet ring＇s size and throat＇s depth of the bell-mouth type shroud, and the through-flow area and configuration of upwind and downwind sections of the outlet grille are the most important factors that affect the aerodynamic performance of the unit. Furthermore, two improved schemes against the existing prototype of the unit are developed, which both can significantly increase the flow rate more than 6 %（i.e. 100 m3·h～（-1）） at given rotating speeds. The inevitable increase of flow noise level when flow rate is increased and the advantage of keeping a lower rotating speed are also discussed. The presented work could be a useful guideline in designing the aerodynamic and acoustic performance of the split air-conditioner in engineering practice.     

Advanced lagged slip ratio for stable analysis of wheel dynamics at low-speed and high-speed

Real-time interpretation of a vehicle is mainly used for the speed estimation of autonomous vehicles and hardware-in-the-loop simulation. For real-time analysis of vehicles, an explicit integrator is more suitable than an implicit integrator. The implicit integrator guarantees the stability of the numerical analysis, whereas the explicit integrator requires a smaller amount of computation, which enables quick analysis. However, the lagged slip ratio, which is the most typical slip ratio in the tire model for vehicle dynamics simulation, shows that the numerical results of the explicit integrator are unstable in low-speed and high-speed driving situations. This is because the pole of the wheel dynamics system applying the lagged slip ratio deviates from the stability region of the explicit integrator depending on the driving speed. Generally, the instability of the lagged slip ratio is eliminated by applying an arbitrary damper system. In this study, an advanced lagged slip ratio is proposed to maintain the pole of the wheel dynamics in the stability region using an explicit integrator. The validity and stability of the proposed method is confirmed by comparing the driving simulation results with the conventional slip ratio.     

基于差动驱动的电子差速控制方法研究

针对目前采用转速或转矩控制模式实现电子差速所存在的问题,提出了一种基于差动驱动的电子差速控制方法,从整车动力学层面上设计了基于滑模控制理论的横摆运动控制模块;在充分考虑轮胎摩擦椭圆和执行机构物理限制的基础上,设计了差动驱动控制模块和滑转率控制模块.研究结果表明,该电子差速控制策略简单有效,不但能保证每个驱动轮都有很好的...     

Modeling and Analysis of A Rotary Direct Drive Servovalve

Direct drive servovalves are mostly restricted to low flow rate and low bandwidth applications due to the considerable flow forces.Current studies mainly focus on enhancing the driving force,which in turn is limited to the development of the magnetic material.Aiming at reducing the flow forces,a novel rotary direct drive servovalve（RDDV）is introduced in this paper.This RDDV servovalve is designed in a rotating structure and its axially symmetric spool rotates within a certain angle range in the valve chamber.The servovalve orifices are formed by the matching between the square wave shaped land on the spool and the rectangular ports on the sleeve.In order to study the RDDV servovalve performance,flow rate model and mechanical model are established,wherein flow rates and flow induced torques at different spool rotation angles or spool radiuses are obtained.The model analysis shows that the driving torque can be alleviated due to the proposed valve structure.Computational fluid dynamics（CFD）analysis using ANSYS/FLUENT is applied to evaluate and validate the theoretical analysis.In addition,experiments on the flow rate and the mechanical characteristic of the RDDV servovalve are carried out.Both simulation and experimental results conform to the results of the theoretical model analysis,which proves that this novel and innovative structure for direct drive servovalves can reduce the flow force on the spool and improve valve frequency response characteristics.This research proposes a novel rotary direct drive servovalve,which can reduce the flow forces effectively.     

ABSs系统模糊控制器优化设计

已经开发了的ABSs系统改善了突然制动和特别是滑动路面状况时车辆控制。这样的控制目标是在保持车辆合适稳定性及可操纵性和缩短车辆刹车距离情况下在要求的方向增大车轮的牵引力。本文提出了ABSs系统优化的模糊控制器。从保持其车轮滑动值为目标函数获得车轮最大的牵引力和车轮最大的减速度。采用遗传算法优化模糊系统的全部组件。采用误差数整体优化方法收敛接近最优点。仿真结果表明快速收敛和对不同路况的控制器的最好性能。     

ASCS Online Fault Detection and Isolation Based on an Improved MPCA

Multi-way principal component analysis（MPCA）has received considerable attention and been widely used in process monitoring.A traditional MPCA algorithm unfolds multiple batches of historical data into a two-dimensional matrix and cut the matrix along the time axis to form subspaces.However,low efficiency of subspaces and difficult fault isolation are the common disadvantages for the principal component model.This paper presents a new subspace construction method based on kernel density estimation function that can effectively reduce the storage amount of the subspace information.The MPCA model and the knowledge base are built based on the new subspace.Then,fault detection and isolation with the squared prediction error（SPE）statistic and the Hotelling（T2）statistic are also realized in process monitoring.When a fault occurs,fault isolation based on the SPE statistic is achieved by residual contribution analysis of different variables.For fault isolation of subspace based on the T2 statistic,the relationship between the statistic indicator and state variables is constructed,and the constraint conditions are presented to check the validity of fault isolation.Then,to improve the robustness of fault isolation to unexpected disturbances,the statistic method is adopted to set the relation between single subspace and multiple subspaces to increase the corrective rate of fault isolation.Finally fault detection and isolation based on the improved MPCA is used to monitor the automatic shift control system（ASCS）to prove the correctness and effectiveness of the algorithm.The research proposes a new subspace construction method to reduce the required storage capacity and to prove the robustness of the principal component model,and sets the relationship between the state variables and fault detection indicators for fault isolation.     

汽车TCS控制算法的研究

驱动力控制系统（Traction Control System,TCS）是在制动防抱死系统的基础上发展起来的一套主动安全控制系统,它根据汽车的行驶状况,通过采用适当的控制算法使汽车驱动轮在恶劣路面或复杂行驶条件下也能产生最佳的纵向驱动力,从而提高汽车的驱动性能和行驶稳定安全性能.通过时TCS控制原理的分析,明确滑转率的控制目标,结合TCS的控制方式,阐述TCS的常用控制算法,并对其进行比较,探讨TCS控制算法的选择依据和方法.     

考虑轮胎无滑移的智能车辆连续曲率轨迹规划方法

提出了无滑移约束条件下,给定起止点位置和状态的可行运动轨迹规划方法。首先根据前轮转向的单轨车辆模型,建立了7维非线性车辆动力学模型。然后基于无滑移假设,推导出前轮转角及其转角变化率的无滑移表达式;利用MNC轮胎/路面模型推导满足车辆无滑移的动力学约束,并据此给出最大速度轮廓曲线。最后利用闭环操纵稳定性评价指标来优化生成的轨迹。仿真结果验证了该方法的有效性。     

轮胎非稳态侧偏特性非线性仿真模型

在稳态指数统一模型的基础上,根据动态过程有效滑移率的微分表达,建立轮胎非稳态侧偏特性非线性仿真模型。在实验中发现当用有效滑移率和准稳态概念来计算回正力臂 Ｄｘ 时,有滑移率超前而回正力臂滞后现象,该现象可以通过一个一阶滤波器来表达。模型的计算结果与实验结果对比,表明该模型可以反映轮胎非线性侧偏特性,可以用于汽车操纵动力学研究。