液压支架直线四杆机构综合的差分进化算法

为使液压支架铰链四杆机构在采高区内具有近似直线轨迹,可利用连杆平面上的拐点性质综合这类四杆机构。以指定采高区内直线偏差最小为目标,以满足Grashof准则、杆长协调、角度限制等为约束条件,建立综合液压支架近似直线导向四杆机构的6参数约束优化模型。结合Deb约束处理可行性规则,应用差分进化(Differential Evolution,DE)算法求解该约束优化问题。给出综合实例,仿真结果表明,该方法是可行有效的。还比较了DE算法与另外3种智能算法求解该机构综合实例的优化性能。数值试验显示,DE算法的收敛速度、收敛精度和稳健性等性能指标优于3种对比算法。     

球面4R机构近似轨迹综合的社会认知优化算法

应用坐标变换原理,推导出球面4R机构连杆点轨迹参数方程。在此基础上,以轨迹误差平方和最小为目标函数,以曲柄存在、杆长协调和传动角限制等为约束条件,建立机构不带预定时标近似轨迹综合的约束优化模型。结合自适应罚函数法,应用社会认知优化(Social Cognitive Optimization,SCO)算法求解该问题。为提高SCO算法的收敛精度和速度,以差分进化(Differential Evolution,DE)操作为邻域搜索算子,设计一种加速社会认知优化(Accelerating Social Cognitive Optimization,ASCO)算法。给出机构综合实例,轨迹分析结果表明,所建立的模型和提出的ASCO算法可行有效。比较了基本SCO、DE和ASCO算法求解该机构综合实例的优化性能,数值实验显示,ASCO算法的收敛速度、收敛精度和稳健性等性能指标优于基本SCO和DE算法。     

并联机构位置正解的自适应差分进化算法

根据杆长约束条件,建立求6自由度一般6-SPS并联机构位置正解的无约束优化模型,再应用差分进化(Differential evolution,DE)算法求解该问题。针对基本DE算法可能出现进化停滞或陷入局部极值区域的缺点,提出一种引入新个体的自适应策略,以增强算法全局优化性能。将引入新个体的自适应策略融入DE算法,并使用混合变异算子及基于三角函数扰动的缩放因子和交叉因子,形成自适应差分进化(Adaptive DE,ADE)算法。数值结果表明,对于一般6-SPS并联机构正运动学分析问题,ADE算法能以较少计算开销求出全部高精度位置正解。通过与基本DE算法、自适应变异粒子群算法和改进人工蜂群算法比较,验证了ADE算法的收敛精度和计算稳健性指标优于对比算法。     

4-PRUR并联机构及其位置分析的差分进化算法

给出1移动3转动(1T3R)对称4-DOF空间4-PRUR并联机构的几何模型,应用螺旋理论分析机构实现1T3R的原理,并讨论输入选取的合理性.根据杆长约束条件,建立机构位置分析的非线性方程组.为改进差分进化算法(Differential evolution,DE)的寻优效率,提出一种基于混沌迁移、最优个体加权处理和群体逃逸策略的自适应双种群差分进化算法(Adaptive differential evolution algorithm with double subpopulations,ADEDS).将机构位置分析中非线性方程组的求解转化为无约束优化模型,并应用ADEDS求解该问题.数值实例表明,ADEDS能求出并联机构的多组高精度位置正解,并通过位置反解验证位置正解的正确性.     

三移动一转动4-RPUR并联机构及其位置分析

提出一种能实现三维移动和绕Z轴转动(3T1R)的新型全对称4-DOF空间4-RPUR并联机器人机构,并建立其几何模型。应用螺旋理论分析4-RPUR并联机构自由度的数目和性质,证明该机构能够实现3T1R运动,验证了选取各支链中的移动副作为驱动副的合理性。以机构杆长为约束条件,建立机构位置正解分析的非线性方程组,再转化为无约束优化问题,并采用差分进化(Differential Evolution,DE)算法求解该问题。给出机构位置逆解的显式解析表达式,且由该式可知,机构最多存在16组位置逆解。为改进差分进化算法的寻优效率,提出一种加权基矢量变异策略。当种群出现进化停滞而陷入局部最优区域时,采用自适应逃逸操作引入新个体,进而增强种群多样性。新型变异策略与自适应逃逸操作结合,形成具有较强全局优化能力的自适应逃逸差分进化(Adaptive Escape Differential Evolution,AEDE)算法。给出机构位置分析数值算例,应用AEDE算法求得所有高精度位置正解,并应用位置逆解验证位置正解的正确性。还比较了基本DE、粒子群优化和AEDE算法求机构位置正解的性能,结果表明:AEDE算法性能均优于比较算法性能。     

基于差分进化算法的六杆间歇机构优化综合

将差分进化算法(DE)应用于六杆机构综合。该方法应用于在规定的时间控制和传动角约束下的具有停歇位置的机构综合。文中给出了计算实例,证明这种方法是可行的。     

基于差分算法的平面连杆机构再现函数综合

主要研究平面连杆机构函数综合问题.根据平面连杆机构函数综合的特点和优化的思想,以杆长和初始角作为设计变量,转角误差和约束条件构造代价函数建立机构优化的数学模型.通过研究差分算法,提出了一种基于差分算法的平面连杆机构函数综合优化设计的新方法.该方法与其它的智能优化设计方法相比较,算法简单,收敛速度快,所需领域知识少,比较适合于解决复杂的优化问题.最后设计实例表明了该方法的可行性和有效性.     

逃逸离散差分进化算法在齿轮传动优化中的应用

根据决策变量映射关系,将齿轮传动设计中的离散约束优化问题转化为约束非负整数规划问题(Constrained non-negative integer programming problems,CNIPPs),并应用离散差分进化(Discrete differential evolution,DDE)算法求解该问题。引入定量评价种群多样性的平均基因距离指标,并据此提出一种采用反向学习算子生成新个体的自适应逃逸策略,以克服基本DDE算法求解离散问题易陷入局部最优区域的缺点。将逃逸策略融入DDE算法,并结合可行性规则约束处理技术,形成求解CNIPPs的逃逸离散差分进化(Escape DDE,EDDE)算法。应用EDDE算法求解齿轮传动优化设计实例,并提出用于比较多种算法优化性能的相对综合性能指标。通过测试与分析可知,新算法具有良好稳健性和可靠性,且综合指标优于对比算法。优化结果明显好于已有文献的最优解,齿轮质量下降了27%。     

混合人工蜂群算法在并联机构尺度优化中的应用

以4-RUPaR并联机构为研究对象,以机构杆长为约束条件,利用解析几何中的坐标变换理论,得到其运动学反解模型,根据该模型,利用所有满足约束条件的"点集"描述并联机构定姿态工作空间大小。建立以并联机构驱动连杆长度、执行连杆长度和动平台尺寸为设计变量,以工作空间最大化作为优化目标的尺度优化模型。在求解多维优化问题时,为提高算法的搜索效率及解的质量,文中将差分进化(Differential Evolution, DE)算法融入人工蜂群(Artificial Bee Colony,ABC)算法,提出一种混合人工蜂群(Hybrid Artificial Bee Colony,HABC)算法,以增强算法的全局优化能力。应用HABC算法求解并联机构尺度优化设计,获得了较好的优化效果。     

空间6R机械臂位置逆解的复合形差分进化算法

以6自由度TX60型Staubli工业机械臂为研究对象,通过运动学分析,建立求解该机械臂位置逆解的非线性方程组。以末端执行器位姿误差最小为目标函数,将非线性方程组转化为无约束优化模型,并应用差分进化算法(Differential evolution algorithm,DE)求解该问题。为克服基本DE难以平衡收敛精度和计算可靠性的缺陷,提出一种自适应分工复合形差分进化算法(Adaptive division complex DE algorithm,ADCDE),以增强优化性能。该算法将种群自适应划分为开采子群和勘探子群,前者采用DE/best/2/bin策略生成变异个体,而后者采用复合形算子生成变异个体。给出工程应用实例,应用ADCDE求串联机械臂的位置逆解。仿真结果表明,该算法的计算精度和可靠性优于对比算法,应用较少计算开销即可求出高精度位置逆解,且能求得所有可能逆解,验证了该方法的有效性和可行性。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.