Multicriterion optimization of the kinematics of the spatial mechanisms of passenger car wheel suspensions

Four spatial mechanisms simulating passenger car wheel suspensions and steering linkages and power drives are considered. A structural analysis of the mechanisms is provided. A method for calculating the coordinates of characteristic points and the main kinematic characteristics of these mechanisms is proposed. The problem of multicriterion optimization of the kinematic characteristics is defined. A subproblem of the multicriterion optimization consists in the synthesis of a mechanism ensuring the required motion of a wheel. Some optimization results are presented.     

Umlauffähigkeit räumlicher mechanismenConditions for the complete rotation of spatial mechanisms

For four-membered plane, spherical and spatial mechanisms whose transfer functions are of the same structure, a common theory for the conditions of complete rotation is given. The transfer equation has to allow for the interpretation as the algebraic correspondence of type (1,2) between two conic sections. For this, the theory of conic pencils is required establishing a complete classification of these drives. The reality of the cluster points and the kind of the conic sections supply information on the conditions for complete rotation and the kind of output motion. The conditions for complete rotation are represented independent of the transmission type.     

Computer-aided kinematic analysis of basic spatial mechanisms

Using the spherical coordinate system in conjunction with the principle of algebraic correspondence between the displacement equations of the plane, spherical and spatial four-bar mechanisms and the plane and spatial slider-crank mechanisms, an efficacious procedure has been developed to carry out kinematic analysis for the coupler and output link of the mechanisms. The iteration-free nature of the procedure precludes any non-convergence problem and the inherent complexity of the 3-dimensional analysis is mitigated substantially.     

A method of the balancing of spatial mechanisms

Spatial mechanisms can constitute units of different types of machines and these mechanisms interact with rotating units. Such machines include, for example, woven fabric sewing machines, knitted fabric overlock sewing machines, industrial robot manipulators and some farm machines. The present paper contains an example of the balancing of a spatial mechanism of the needle arm drive on an overlock sewing machine at a stage of design.     

Velocity fluctuation in spatial slider crank mechanisms

Velocity fluctuations have been recognized as important in the statics and dynamics of mechanisms [1]. The geometric conditions governing the existence of extreme velocity ratios in a spatial 4-link mechanism having two revolute, one cylindrical and one prismatic pair have been obtained. The present investigation presents an algebriac solution of the velocity fluctuation problem. It is shown that, in the general case, the extreme velocity ratios must be among the real roots of an 8th degree polynomial in gemometric parameters of the mechanism. The extreme velocity ratios of any given mechanism can be obtained from the above results. Numerical example is presented to illustrate the procedure.The results presented in this paper can be extended to synthesize a spatial four link mechanism with prescribed extreme velocity ratios.     

集中柔度全柔性机构拓扑优化设计研究

根据集中柔度全柔性机构特点,基于连续体拓扑优化技术,采用SIMP人工材料密度方法.以机构的刚度和柔度要求相结合的功能函数作为优化目标,建立集中柔度全柔性机构拓扑优化设计模型.采用优化准则法进行数值计算,并推导了迭代公式.通过所建立的优化模型设计出的机构拓扑图形具有"集中柔度"特征,为集中柔度全柔性机构的设计提供了基础.数值算例证明了研究方法的有效性.     

空间连杆机构运动分析可视化

可视化技术可以使空间机构的运动分析更加直观.以空间RSSR机构为例,运用MATLAB、ADAMS等可视化技术,分析机构的可动性,并利用图表和动态图像显示其位移、速度及加速度等计算结果.     

空间RSSR机构轨迹数字化综合

提出一种新的机构综合方法；数字化综合，并根据其原理编制了相应计算机程序，经实践检验，与现行各种方法有本质区别，功能更强，更方便实用。     

新型增力液压缸的结构与参数设计

设计了一种超高压增力液压缸,有效地减小增力装置的外形尺寸,并提高输出负载力.在功能结构设计上,使增压腔与外部低压回路隔离,采用特殊的密封件实现运动部件的超高压密封.根据超高压的特殊使用要求,进行了输出缸和增压缸的参数设计,并采用有限元软件ANSYS进行了强度校核.     

空间RSSR机构运动分析的研究

以RSSR机构为例研究了运动分析结果的可视化问题,首先使用解析法对RSSR机构建立运动分析模型,得到运动分析方程,并通过Matlab函数绘制了输出构件的角位移、角速度、角加速度图;其次基于SolidWorks平台三维建模,使用COSMOSMotion进行运动仿真,也得到对应的运动分析结果.通过运动分析的结果对比是完全相同的,但是采用三维参数化软件进行机构运动分析方法过程简单方便,是空间机构运动分析的发展方向.     

Using genetic algorithms for the optimization of mechanisms

This work examines the possibility of using genetic algorithms for the optimization of the loads transmitted in mechanisms. The variables of design are the relative positions of the various connections, considered in a comparative manner. The minimization of the loads transmitted in the connections is achieved by optimizing the respective positions of those lead to less expensive solutions for bearings and sections of beams. The examples show that using this stochastic method is an efficient way to minimize loads in mechanisms.     

On the kinematic synthesis of 5-axis spatial mechanisms

In the present study the possibilities of kinematic synthesis of 5-axis spatial mechanisms are explored, in order to elaborate a design method for achieving associated positions and velocities imposed on input and output links. Structural schemes of 3R-2C mechanisms together with the appropriate mathematical algorithms for their synthesis are suggested. In completion one presents a computer-aided procedure for the kinematic systhesis, directly usable by the designer.     

基于螺旋理论的空间机构自由度分析方法

将螺旋理论应用于空间机构的自由度分析中,采用螺旋理论中的运动螺旋和力螺旋分别来表示空间机构的自由度和约束,并利用螺旋理论中的互逆原理,对空间机构进行约束和自由度分析,总结出求解空间机构的自由度和过约束的方法,举出算例.研究从自由度和约束的基本概念入手,从而保证了方法的准确性和通用性.     

Automatic assembly task of electric line using 6-link electro-hydraulic manipulators

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today’s highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.     

Unified synthesis of Watt-I six-link mechanisms using evolutionary optimization

A Watt-I mechanism can operate in eight different combinations of assembly modes and output link. In this paper, a novel approach is presented for carrying out unified optimum synthesis of various combination types of Watt-I mechanism, irrespective of whether identical or different ranges of variables are specified for different combination types. By carrying out unified synthesis the less suited combination types can be identified, leading to their elimination from the synthesis process. This results in a saving of the overall computational time. The presented approach can be implemented with most of the evolutionary optimization methods. In this paper, the Differential Evolution algorithm is chosen as the optimization method. Unified optimization results are presented for two problems. The proposed approach is general and can be used, with suitable modifications, to carry out unified optimum design of alternate mechanical systems which can perform a given task.     

空间机构位置分析的矢量回归法

本语文给出了一适中矢量回归公式，用来解决空间机构位置分析问题。该方法不需要引入坐标系，计算量小，具有通用性，易于写电算程序，是一种易于掌握的简便方法。     

A displacement analysis of the general spatial 7-link, 7R mechanism

An input-output equation of degree 32 in the tan-half-angle of the output angular displacement is expressed in the form of a $\text{16 × 16}$ determinant equated to zero for the single-loop, single-degree-of-freedom linkage with seven links connected by seven turning pairs arbitrarily oriented in space. An algorithm is developed for computing values of the remaining angular displacements of the mechanism. The results are verified by numerical examples.The derivation of the input-output equation and the development of the algorithm are outlined before proceeding with the detailed algebraic analysis. The detailed analysis is performed using a unified theory for the analysis of spatial mechanisms [1,2] which was developed using a treatise on spherical trigonometry by Todhunter and Leatham [3].     

Computer-oriented method for linearization of dynamic models of active spatial mechanisms

A new computer oriented method for linearized dynamic model construction of open-chain active mechanisms is developed. The method is an extension of an existing algorithm for automatic setting of nonlinear dynamic models [1,2], based on general theorems of mechanics. The developed procedure involves vectorial algebraic recursive relations, but not numerical differentiation and other numerical operations which cause cumulative computing errors. Such a method is of essential importance in manipulation robot control synthesis when small perturbations are present. The results of application of the algorithm to three joints of a 6 degrees-of-freedom manipulator system are given.     

The singularity study of spatial hybrid mechanisms based on screw theory

In this paper, a novel methodology based on screw theory to study the singularity of spatial hybrid mechanisms is presented. According to the physical meaning of inverse screws, we introduce the equivalent kinematic screws to replace the function of those of the parallel limbs, and therefore the hybrid branch can be transformed into a pure series kinematic chain which can facilitate the whole analytical process of the singularity of complex spatial hybrid mechanisms. In fact, this methodology can be widely used to solve the singularity problems of spatial hybrid mechanisms based on the analysis of their kinematic characters.