Behavioural modelling for design decomposition and design equations derivation

Analysis of system performance is necessary at various stages of the design process. For this purpose, design equations should be identified or derived, which establish the links between the required performance and the physical structure of the designed system and system inputs/outputs. There has been no generic methodology for the derivation of design equations at the early design stage. In this paper, we present a behavioural modelling methodology to address the problem. It is achieved by modelling the system behaviours as one or more behavioural processes, and deriving design equations from each individual behaviour of the process. To simplify the task as well as those subsequent design tasks, we also discuss the issue of performance analysis oriented design decomposition. This is achieved by developing two design hierarchies with established links between them. An algorithm for automatic design decomposition is subsequently proposed. This algorithm is applicable both before and after the derivation of design equations. Finally, a design case is also studied to illustrate and demonstrate the proposed methodologies.     

接头定位器在装配型架设计中自动选取的研究与实现

阐述了接头定位器在飞机装配型架装配中的定义和表示的概念,根据飞机装配型架设计的几何约束关系,得到基于几何约束不等式方程组和求解不等式方程组的最优解,并将最优解驱动接头定位器在装配型架设计中自动选取.     

冲压焊接多级离心泵的理论研究及工程实现

提出了把"理想流体"作为参照量,把粘性边界层作为水流动边界条件的粘性水力设计方法。针对冲压焊 接多级离心泵吸入口的流态,推导出了粘性条件下的畸变方程式和输运方程式,以此应用于冲压焊接多级离心泵 的水力设计,实践应用改善了冲压焊接多级离心泵的性能,提高了运行效率。     

Design equations for the complete shaking force balancing of 6R 6-bar and 6-bar slider-crank mechanisms

The article presents the design equations for complete shaking force balancing of commonly used planar Stephenson's and Watt's type 6R 6-bar and 6-bar slider-crank regular force transmission mechanisms using the method of linearly independent mass vectors. Regular force transmission mechanisms are those in which the shaking force can be completely balanced by distributing the masses of the existing links. Design equations are developed by considering the existing links. Design equations are developed by considering mass distributions of the coupler links and sliders specified whenever possible, so that the counter-balancing masses are mounted on the shafts supported by the fixed frame of the mechanism. Industrial design applications of the design equations given are illustrated in two numerical examples where the shaking force in a Stephenson's Type-1 6R mechanism and a 6-bar double-slider-crank mechanism used in V-engines is balanced.     

摆线齿锥齿轮的产成原理及其产形面方程

根据加工中摆线齿锥齿轮、工作台及刀盘的相对运动关系,推导出变位情况下摆线齿锥齿轮产形面方程,据此可以导出啮合线、齿轮啮合面方程,对于进一步研究该类型锥齿轮的齿面特点和啮合特性及其加工有一定的参考价值.     

Synthesis of planar linkage via loop closure and nonlinear equations solution

This paper discusses the loop closure equations and the solution of these nonlinear equations in the design of planar linkages. It includes a brief review of some contemporary methods of synthesis and their comparative analysis. Illustrative examples are also presented.     

不同工况下角接触轴承接触角分析与研究

以 Hertz 接触理论为依据，根据角接触球轴承的三种工况建立了轴承的拟静力学模型，得到角接触球轴承的非线性方程组，通过采用牛顿-拉夫逊迭代算法求解非线性方程组，得到角接触球轴承在不同工况下的内、外接触角变化规律，为角接触球轴承的设计与分析提供了理论基础。     

Two general solutions of torsional compliance for variable rectangular cross-section hinges in compliant mechanisms

Several approaches exist for calculating the torsional compliance of rectangular cross-section beams, but most depend on the relative magnitude of the cross-section thickness and width, which might be changing during the design phase (especially for design optimization) or is variant for variable cross-section beams such as circular flexure hinges and tapered bars. After summarizing current equations and analyzing their computational accuracy, two new equations are proposed, which are thickness-to-width ratio independent, and suitable for variable cross-section beams and optimization design of torsional elements in compliant mechanisms. The closed-form equations for the torsional compliance of elliptical and circular flexure hinges are derived by using the new equations.     

软式操纵系统中张力调节器的设计研究

软式操纵系统是通过钢索张力来传递操纵力的,钢索张力的变化直接影响飞机的操纵性能。张力调节器就是使钢索在各种状态下保持张力恒定的一种调节装置。对张力调节器的原理、结构形式进行了综合论述,并结合设计实例来说明钢索张力调节器的设计过程及设计中各参数的选取原则。     

Design of Dyads with helical,cylindrical, spherical,revolute and prismatic joints

In this paper, an “equivalent screw triangle” is introduced from which the design equations can be determined for any combinations of helical, cylindrical, revolute, spherical, and prismatic joints for both finitely and infinitesimally separated position problems in kinematic synthesis. In addition to presenting a new and unified approach to previously solved problems, this paper presents an entirely new treatment of helical joints. The equations developed in this paper can be applied to the design of binary links for rigid body guidance, function generation and similar problems. A numerical example illustrating the design of H-H links is included.     

Sensor fault detection and isolation system for a condensation process

This article presents the design of a sensor Fault Detection and Isolation (FDI) system for a condensation process based on a nonlinear model. The condenser is modeled by dynamic and thermodynamic equations. For this work, the dynamic equations are described by three pairs of differential equations which represent the energy balance between the fluids. The thermodynamic equations consist in algebraic heat transfer equations and empirical equations, that allow for the estimation of heat transfer coefficients. The FDI system consists of a bank of two nonlinear high-gain observers, in order to detect, estimate and to isolate the fault in any of both outlet temperature sensors. The main contributions of this work were the experimental validation of the condenser nonlinear model and the FDI system.     

SolidWorks零件设计控制中方程式的应用

针对实际设计中,存在着大批量要求结构相似而尺寸规格不同的系列产品的设计,介绍了SolidWorks软件中方程式的应用,以及如何通过方程式的应用来高效率地实现零件的尺寸设计控制和修改。     

Symmetric Equations for Evaluating Maximum Torsion Stress of Rectangular Beams in Compliant Mechanisms

There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions of the crosssection(i.e., the thickness and the width). After reviewing the available equations, two thickness-to-width ratio Independent equations that are symmetric with respect to the two dimensions are obtained for evaluating the maximum torsion stress of rectangular cross-section beams. Based on the resulting equations, outside lamina emergent torsional joints are analyzed and some useful design Insights are obtained. These equations, together with the previous work on symmetric equations for calculating torsional compliance, provide a convenient and effective way for designing and optimizing torsional beams in compliant mechanisms.     

平面包络弧面分度凸轮机构凸轮廓面方程与啮合特性的研究

本文将业已成熟的蜗轮蜗杆传动技术引入到弧面分度凸轮机构的研究中,提出了一种新型的平面包络弧面分度凸轮机构,并推导了该机构的凸轮廓面方程,啮合方程和两类界限曲线方程,最后给出了这种机构良好的啮合特性和加工工艺性,为该机构的分析,设计和制造提供了理论依据。     

Modeling of flexure-hinge type lever mechanisms

A general approach for the design of flexure-hinge type lever mechanisms that are commonly used in the design of translational micro-positioning stages is presented in this paper. The paper focuses on the development of design equations that can accurately predict the behavior of such stages especially the “lost motion” due to hinge stretching. The development of these equations is based on a static analysis of a general configuration of a single-axis, translational, flexure-hinge type, piezo-driven micro-positioning stage using a multi-lever structure. The displacement ratio between the input and output motions of one of the levers, plus the stiffness at either end of this lever are obtained based on the analysis. The overall displacement and stiffness of the micro-positioning stage are then obtained by cascading the individual results from every lever. The developed equations include the effects of the flexure hinge bending and stretching. The developed equations were applied to design of a vertical motion micro-positioning stage. The stiffness and displacement of this stage are predicated by these equations, which are compared to the stiffness and displacement directly obtained from the finite element modeling and actual testing of the same micro-positioning stage. The comparison shows that the analytical approach gave nearly similar results (within 10%), which implies that the developed equations can accurately predict the characteristics of flexure-hinge type lever mechanisms.     

Design, modelling and errors measurement of wheeled mobile robots

This paper presents the mechanical design process of an omni-directional mobile robot. In addition, the kinematics equations of the final design are derived, and the inverse Jacobian matrix of the robot is presented. The dynamic equations of motion for the final design are derived in a symbolic form, assuming that no slip occurs on the wheel in the spin direction. In order to validate the kinematics and dynamic equation, we carried out consequences of simulation using two pieces of software, Maple and Working Model. Finally, the mobile robot is moved in given trajectories and the systematic errors of the robot are determined. To overcome the problems, a new method was introduced in which the robot was programmed to move in the direction of each wheel shaft.     

Generation automatique et simplification des equations litterales des systemes mecaniques articulesAutomatic generation and simplification of literal equations modeling articulated mechanisms

This paper presents a method of automatic generation and simplification of literal equations for modeling articulated mechanisms. This method is based both upon a formal representation leading to easy implementation on a micro-computer and a very careful design of the symbolic calculus modules constituting the software. Throughout the computation of the terms of the equations they are systematically simplified and condensed so that the final literal equations are as short as possible and so that their numerical solution requires the lowest possible number of equations. The efficiency of the method increases with the complexity of the modeled mechanism.     

基于Pro/E和Adams的共轭凸轮设计与仿真

用解析法对共轭凸轮曲线进行方程的推导,以摆动滚子从动件共轭凸轮为例结合Pro/Engineer开发实行三维参数化设计,再将设计后的组件导入Adams进行模拟仿真。这样不但使解析法设计变得大为简洁,而且使后续的分析也变得更为可观,从而提高了设计效率和质量,缩短了开发周期。     

基于速度要求的曲柄滑块机构设计及Excel仿真

根据滑块特定位置的速度要求对曲柄滑块机构进行设计,并得出机构几何尺寸计算公式,然后举一实例并利用Excel软件对设计结果进行仿真验证,对曲柄滑块机构的设计具有指导意义.     

Dynamic modeling, input-shaped maneuvering and vibration suppression of flexible body using quasi-coordinates and euler parameters

In dealing with the dynamics of a flexible body, the rigid-body motions and elastic vibrations are analyzed separately. However, rigidbody motions cause vibrations, and elastic vibrations affect rigid-body motions, indicating the inherent coupling between rigid-body motions and elastic vibrations. The coupled equations of motion for a flexible body can be derived by means of Lagrange’s equations in terms of quasi-coordinates. The resulting equations of motion are hybrid and nonlinear. This paper proposes a unified approach for the equations of motion for a flexible body based on the perturbation method and the Lagrange’s equations of motion in terms of quasicoordinates and Euler parameters to analyze a more general case maneuvering. The resulting equations consist of zero-order nonlinear equations of motion which depict rigid-body motions and first-order time-varying linear equations of motion which depict perturbed rigid-body motions and elastic vibration. Hence, the input-shaped maneuvering can be applied to the zero-order equation considering the induced vibrations. Since the input-shaped maneuvering alone cannot achieve vibration suppression, the vibration suppression controller combined with the input-shaped maneuvering is proposed in this study. As a numerical example, a hub with elastic appendages is considered. Numerical results show that the unified modeling approach proposed in this paper is effective in numerical simulation and control design.