基于遗传算法的注塑机肘杆机构优化设计

遗传算法对于多参数系统优化设计具有较好的鲁棒性。针对注塑机肘杆机构优化设计的问题,通过对注塑机单肘杆合模装置的运动分析,建立了数学模型。以肘杆机构长度最小为目标,利用遗传算法进行了优化设计,并与常规设计方法进行了比较。研究结果表明,基于遗传算法的优化设计体现出了明显的优化效果,具有一定的实际应用价值。     

液压驱动双曲肘斜排列七支点合模机构的分析研究

双曲肘斜排列七支点合模机构是一种创新的注射机合模机构,液压驱动系统根据肘杆机构的特性进行设计,两者之间相辅相成使机构的性能进一步提高。研究了机构的运动学、力学的性能,分析了机构运行性能与液压驱动性能之间的关系,提出了机构的机械和液压的主要技术参数的理论计算和设计准则,并通过实例验证了设计理论计算和公式的可行性,为机构的开发和应用提供了理论基础和工程设计方法。实例研究表明,双曲肘斜排列七支点合模机构同比双曲肘斜排列五支点合模机构,行程比大于一倍,液压驱动节能35%,系统液压驱动装载功率下降40%。     

油缸驱动肘杆机构合模部件开模瞬时停顿的研究

油缸驱动肘杆机构合模部件触动系统在注塑成型的开模过程中出现的瞬时停顿的不连续运动现象,分析了肘杆机构合模部件弹性变形能的实质,从理论和实例上对瞬时停顿的不连续运动现象进行论证,说明主要原因是由于油缸动力驱动系统与肘杆机构合模部件弹性力学的两者之间的动态性能不匹配所引起。提出的油马达—滚珠丝杆—肘杆机构等组合的传动系统,改变了合模部件弹性恢复能量转化型式,达到弹性恢复不干涉开模运动速度,实现开模的连续运动;传动系统组成型式的改变,打破传动的油缸驱动肘杆机构合模部件传动系统的增力比的设计极限,由传统的约20倍可增大到约100倍,实现肘杆机构合模部件节能降耗驱动的突破,拓展了运动性能优化设计空间。     

注塑机双肘杆锁模机构的优化设计

推导了双曲肘合模机构行程比和力的放大比与肘杆尺寸及肘杆轴线夹角的关系公式,并应用MATLAB优化模块探讨了肘杆机构的尺寸优化问题.所取得的满意解明显优于现行设计.为实际工程设计方案的选择提供了依据.     

技术文摘专栏

七支点合模机构及其液压驱动的两者互联关系的分析设计 【摘要】：双曲肘斜排列七支点合模机构是一种创新发明的新颖的合模机构,液压驱动系统基于肘杆机构的特性进行设计,两者之间相辅相成使机构的性能得到进一步提高。研究了液压驱动系统与机构的运动学、力学的性能之间的关系,     

注塑机双曲肘合模机构的多目标优化研究

分析了五点斜排注塑机双曲肘合模机构的运动特性和力学特性,建立了合模机构的多目标优化数学模型。在综合考虑合模机构总长、行程比和力的放大比之间的关系的基础上,运用MATLAB优化工具箱中不同的优化函数对比研究了以不同目标组合为对象的优化结果。运用ADAMS建立了合模机构的参数化模型,并在ADAMS中对各种不同的优化方案进行对比仿真分析。结果表明,优化后的合模机构行程比增加、力的放大比增大且结构更加紧凑,为合模机构的设计提供了积极的理论依据。     

注塑机肘杆合模机构弹性力学性能的探讨

从注塑机肘杆合模机构弹性变形的运行特征进行分析研究，介绍了作者对弹性力学在注望机肘杆合模机构中研究应用的一些成果。研究了拉杆和肘杆两者之间抗拉刚度的关系，提出了拉杆及肘杆根据拉伸刚度的设计方法及准则；研究了推力座导杆、销轴、模板支架、模板等抗弯挠度的特征及其相互之间的联系，提出了有关零件抗弯挠度的设计方法及准则；研究了有关零件的挠度和强度之间的内在联系，提出了根据挠度要求进行强度设计的准则。     

液压驱动双曲肘斜排列七支点合模机构的分析研究(续)

双曲肘斜排列七支点合模机构是一种创新的注射机合模机构,液压驱动系统根据肘杆机构的特性进行设计,两者之间相辅相成使机构的性能进一步提高.研究了机构的运动学、力学的性能,分析了机构运行性能与液压驱动性能之间的关系,提出了机构的机械和液压的主要技术参数的理论计算和设计准则,并通过实例验证了设计理论计算和公式的可行性,为机构的...     

七支点合模机构及其液压驱动的系统的分析及设计的研究

双曲肘斜排列七支点合模机构是一种创新发明的新颖的合模机构,液压驱动系统基于肘杆机构的特性进行设计,两者之间相辅相成使机构的性能得到进一步提高.研究了液压驱动系统与机构的运动学、力学的性能之间的关系,提出了液压驱动系统的主要技术参数的计算理论和设计准则,并通过实例验证了设计计算理论和公式的可行性,为机构的开发和应用提供了理论基础和工程设计方法.     

注塑机负后角型肘杆机构的优化及特性分析

讨论新型的注塑机负后角肘杆机构的特点,并通过MATLAB软件分别对正后角和负后角肘杆机构进行多目标规划问题的优化计算.分别利用MATLAB及Pro/E软件对肘杆机构进行运动仿真,并对比两种结构的运动与力学特性.对负后角型注塑机合模机构的性能分析、设计及优化方法均作了详细介绍.     

新型基于6—PSS三维平台机构的并联微动机器人

提出一种新颖的基于6－PSS并联三维平台机的微动机器人并介绍其结构布局特点,应用Jacobian矩阵和力Jacobian矩阵的子阵,分别对其线速度与角速度和力与力矩的各项同性进行了分析计算,并建立显式的微位移正解和反解方程,为其设计和使用提供理论依据。分析计算结果表明,该微动机器人算法与控制简单,微位移解耦和速度与力向向同性,具有最佳的运动和力传递性能。     

腿轮式机器人的运动原理及参数优化

分析了一种腿轮式机器人的运动原理，基于腿轮式机器人的运动参数对机器人的运行性能有较大影响，提出采用遗传算法进行参数优化设计。给出了遗传算法的具体寻优步骤，并得到了最优解，为机器人的机构设计和运动控制提供了理论依据。     

Development of a high precision flexure-based microgripper

This paper presents the design and development of a high precision microgripper for micromanipulation. The design is based on a hybrid flexure-based compliant mechanism and a bias spring structure which render high fidelity and inherent mechanical advantages. Finite element analysis (FEA) was conducted to evaluate responses of the model under specified load and displacement to investigate optimum design of the model. The prototype of the proposed microgripper was fabricated using electro-discharge machining (EDM) process. An experimental study of the performance was carried out and the results are presented. The experimental results are also compared with the computational analysis results. The results show that a high level of displacement amplification and a maximum stroke of 100 μm can be achieved.     

双曲肘连杆式合模装置数字样机刚柔耦合问题求解方法

目前精密塑料注射成型装备的数字样机广泛采用多刚体动力学系统,没有考虑机构运动过程中构件的内应力大小和分布情况,难以求解大位移的合模运动与小位移的结构变形的相互耦合问题。针对精密塑料注射成型装备复杂的动力学特性,建立双曲肘连杆式合模装置数字样机,并在此基础上柔性化处理拉杆、十字头连杆、前肘杆、销轴等关键零部件,获得拉杆的前22阶模态。在合模装置数字样机的仿真分析中,十字头连杆起动过程出现速度拐点,需要考虑十字头连杆的弹性变形。对双曲肘连杆式合模装置数字样机进行刚柔耦合动力学分析,通过中心差分法,求解合模装置数字样机起动过程中十字头连杆的弹性变形,为精密塑料注射成型装备新产品的开发提供了可借鉴的方法。     

MEMS in-plane motion/vibration measurement system based CCD camera

We report on the development of a vibrometer for in-plane motion which is particularly suitable for Micro Electro Mechanical System (MEMS) samples. The system combines a conventional microscope, coherent electronics and a Full Frame CCD camera. Stroboscope lighting allows the system to freeze the motion. The obtained images correspond to different phases of the sample motion. Different subpixel motion measurement algorithms are compared in terms of precision and computation time. An algorithm that we specially design for this application proved to be the best. It is based on the shift Fourier theorem and uses first harmonics, where most energy is present. Thus the system allows computing the phase and magnitude of the sample displacement. With the system we can obtain a measurement resolution of 100 pm demonstrated on the AFM cantilever vibrations measurement. The effect of the edge roughness was studied. It decreases the performance of the algorithm but roughness is very low on most MEMS applications. This method based on a CCD camera, is very well suited for measuring in-plane MEMS vibration since it does not require surface roughness for scattering the light as with the speckle methods (for example). It can quickly obtain full field motion, with a high precision. Furthermore, the used algorithm is simple, fast and very noise insensitive.     

一种平面框架结构优化设计

利用MSCNastran软件对平面框架结构的应力分布及位移变形进行了分析。利用其便捷的前后处理软件MSC．Patran建立了几何模型和有限元分析模型,利用MSC．Nastran对模型进行了计算,得到应力分布和变形分布,并利用优化模块Nastran—Opt以质量最小为目标函数进行了优化,得出质量最小的最佳设计,为工程实际应用提供了理论依据。     

遗传算法在串-并联冗余系统可靠性优化设计中的应用

串-并联冗余系统可靠性的最优设计是可靠性技术中一个十分重要的问题。讨论了遗传算法及其在串-并联冗余系统可靠性优化设计中的应用。串-并联冗余系统具有冗余单元和可选设计，其可靠性优化设计是一高度非线性、具有多极值点、有约束的整数规划问题，传统的解决方法往往对于连续实数域有效可行，而对于解决此类多变量，离散型整数域取值的复杂的优化问题则往往很困难。由于遗传算法是一类全局收敛算法，它用点群进行寻优，而不是用一个单点进行寻优，具有隐含并行算法的特点，从而能够得到全局最优解。所给出的实例说明本文的算法是有效可行的。     

Kinematic design of an anthropomimetic 7-DOF cable-driven robotic arm

In this paper, an anthropomimetic design of a 7-DOF dexterous robotic arm is proposed. Similar to the human arm, the arm consists of three sequentially connected modules, i.e., a 3-DOF shoulder module, a 1-DOF elbow module, and a 3-DOF wrist module. All three arm modules are also driven by cables in order to mimic the driving scheme and functionality of the human muscles. This paper addresses three critical design analysis issues, i.e., the displacement analysis, the tension-closure analysis, and the workspace analysis. A closed-form solution approach is presented for the forward displacement analysis, while the inverse displacement solution is obtained through an efficient optimization algorithm, in which both task-decomposition and dimension-reduction techniques are employed. An effective tension-closure analysis algorithm is also formulated based on the theory of convex analysis. The orientation workspace for the 3-DOF shoulder and wrist modules are then analyzed using a new equi-volumetric partition scheme based on the intuitive Tilt-and-Torsion angle parameterization. An optimization approach is then investigated for the kinematic design of the three joint modules, in which the design objective is to maximize the matched workspace of the robotic arm joints with that of the human arm joints. A research prototype of the 7-DOF cable-driven robotic arm has also been developed in order to demonstrate the anthropomimetic design concept. With a lightweight structure of 1 kg, the cable-driven robotic arm can carry a payload of 5 kg and has motion repeatability of±2.5mm.     

Optimum surface roughness in end milling Inconel 718 by coupling neural network model and genetic algorithm

In this study, optimum cutting parameters of Inconel 718 are determined to enable minimum surface roughness under the constraints of roughness and material removal rate. In doing this, advantages of statistical experimental design technique, experimental measurements, artificial neural network and genetic optimization method are exploited in an integrated manner. Cutting experiments are designed based on statistical three-level full factorial experimental design technique. A predictive model for surface roughness is created using a feed forward artificial neural network exploiting experimental data. Neural network model and analytical definition of material removal rate are employed in the construction of optimization problem. The optimization problem was solved by an effective genetic algorithm for variety of constraint limits. Additional experiments have been conducted to compare optimum values and their corresponding roughness and material removal rate values predicted from the genetic algorithm. Generally a good correlation is observed between the predicted optimum and the experimental measurements. The neural network model coupled with genetic algorithm can be effectively utilized to find the best or optimum cutting parameter values for a specific cutting condition in end milling Inconel 718.     

一种蝶阀密封副的优化设计方法

以蝶阀结构特征为基础,建立了合理的描述密封副结构的数学模型;提出能够准确描述密封副摩擦特性的接触角,并推导出接触角与密封副结构参数之间的数学关系式。从一全新的设计角度研究了密封副启闭摩擦特性;以接触角为基础创建了统一的密封副启闭过程不干涉的判据;以密封副结构参数为设计变量、接触角的倒数为目标函数、启闭不干涉判据为约束条件,建立了密封副最优化设计模型。该理论具有重要的学术价值和广阔的应用前景。