Optimum Synthesis of Plane Mechanisms for the Generation of Paths and Rigid-Body Positions via the Linear Superposition Technique

1975 ◽  
Vol 97 (1) ◽  
pp. 340-346 ◽  
Author(s):  
C. Bagci ◽  
In-Ping Jack Lee
Keyword(s):  
Rigid Body ◽  
System Design ◽  
Linear Superposition ◽  
Loop Closure ◽  
Numerical Examples ◽  
Optimum Synthesis ◽  
Closure Equation ◽  
Superposition Technique

A method of optimum synthesis of plane mechanisms for the generation of paths and rigid-body positions is presented. The method is developed for the four-bar plane mechanism with six and eight unknown dimensions. Dimensions of the optimum mechanism are determined by minimizing the error in the loop-closure equations for N design points on the path, along with the loop-closure equation of the linkage, where N is not limited by the number of the unknown dimensions of the system. Design equations are linearized by the method of linear superposition. Solution of design equations requires no iterations, and it leads to a series of optimum mechanisms of different efficiency of approximation. Numerical examples are given.

Optimum Synthesis of Multiloop Planar Mechanisms for the Generation of Paths and Rigid-Body Positions by the Linear Partition of Design Equations

1977 ◽  
Vol 99 (1) ◽  
pp. 116-123 ◽  
Author(s):  
D. H. Bhatia ◽  
C. Bagci
Keyword(s):  
Rigid Body ◽  
Mechanism Design ◽  
Industrial Applications ◽  
Planar Mechanisms ◽  
Loop Closure ◽  
Optimum Synthesis ◽  
Linear Partition ◽  
Closure Equation

The optimum synthesis of multiloop planar mechanisms for the generation of paths and rigid-body positions employing the linear partition of the design equations is presented. Design equations and their applications for the optimum synthesis of the three distinct types of the Stephenson’s six-bar mechanism for the generation of paths and rigid-body positions are presented. The optimum sets of dimensions of a mechanism are determined by minimizing the error in the loop-closure equation of the path dyad and of the loops of the mechanism. Design equations having nine to twelve unknown dimensions are presented. Industrial applications of the design equations are illustrated with design examples.

Analysis of the single toggle jaw crusher kinematics

2015 ◽  
Vol 13 (2) ◽  
pp. 213-239 ◽  
Author(s):  
Moses Frank Oduori ◽  
Stephen Mwenje Mutuli ◽  
David Masinde Munyasi
Keyword(s):  
Design Methodology ◽  
Loop Closure ◽  
Content Type ◽  
Drive Mechanism ◽  
Jaw Crusher ◽  
Closure Equation

Purpose – This paper aims to obtain equations that can be used to describe the motion of any given point in the swing jaw of a single toggle jaw crusher. Design/methodology/approach – The swing jaw drive mechanism of a single toggle jaw crusher is modelled as a planar crank and rocker mechanism with the swing jaw as the coupler link. Starting with the vector loop closure equation for the mechanism, equations of the position, velocity and acceleration of any given point in the swing jaw are obtained. Findings – Application of the kinematical equations that were obtained is demonstrated using the dimensional data of a practical single toggle jaw crusher. Thus, a description of the kinematics of any given point in the swing jaw of a single toggle jaw crusher is realized. Originality/value – The model of the single toggle jaw crusher mechanism as a planar crank and rocker mechanism is a realistic one. The equations obtained in this paper should be useful in further studies on the mechanics and design of the single toggle jaw crusher.

Pseudo-Rigid-Body Model Chain Algorithm: Part 2 — Equivalent Representations for Combined Load Boundary Conditions

2006 ◽  
Author(s):  
Joby Pauly ◽  
Ashok Midha
Keyword(s):  
Boundary Conditions ◽  
Rigid Body ◽  
Compliant Mechanism ◽  
Loop Closure ◽  
Combined Load ◽  
Body Model ◽  
Rigid Body Model ◽  
Planar Vector ◽  
Flexible Segment ◽  
Model Chain

Pseudo-rigid-body models help expedite the compliant mechanism design process by aiding the analysis and synthesis of candidate design solutions, using loop-closure techniques for rigid-body mechanisms. Presently, these models are available only for relatively simple compliant beam geometries and loading situations. The pseudo-rigid-body model chain algorithm provides reasonable approximations of the deformed shape of complex compliant members; however, it has one major limitation. The elastic deformation of each compliant segment under combined load boundary conditions is obtained by superposing the pseudo-rigid-body model displacements due to i) the force and ii) the moment loads, respectively. Hence, each segment needs to be characterized by two separate pseudo-rigid-body models in order to accurately determine its deformation kinematics. Such an idealization of compliant segments would present significant challenges when attempting to represent the pseudo-rigid-body model chain in vectorial form, as in planar vector loop-closure methods. Vectorial modeling would be possible if each flexible segment in the chain could be represented by an “equivalent pseudo-rigid-body model.” This paper proposes the concept of a rudimentary equivalent pseudo-rigid-body model to represent compliant segments with combined load boundary conditions in the pseudo-rigid-body model chain algorithm. Such a model may help overcome the difficulties confronted in the potential implementation of the pseudo-rigid-body model chain in planar vector loop-closure solution techniques.

Incompletely Specified Displacements: Geometry and Spatial Linkage Synthesis

1973 ◽  
Vol 95 (2) ◽  
pp. 603-611 ◽  
Author(s):  
Lung-Wen Tsai ◽  
Bernard Roth
Keyword(s):  
Rigid Body ◽  
Screw Axis ◽  
Numerical Examples ◽  
Spatial Linkages ◽  
Free Parameters ◽  
Analytical Expressions ◽  
Linkage Synthesis

The screw axis geometry associated with displacements of points and lines is studied. Analytical expressions are developed for rigid body screw displacements which have one or more free parameters. It is shown how to apply these results to the synthesis of spatial linkages. The theory is illustrated by numerical examples in which Cylindric-Cylindric cranks are designed to guide two points in a rigid body through five and then nine specified positions.

ON THE COUPLER CURVE OF 3R2C LINKAGES

1998 ◽  
Vol 22 (3) ◽  
pp. 251-267
Author(s):  
H.S. Yan ◽  
W.H. Hsieh
Keyword(s):  
Algebraic Curve ◽  
Three Dimensions ◽  
Critical Properties ◽  
Dimensional Synthesis ◽  
Analytical Geometry ◽  
Loop Closure ◽  
Input And Output ◽  
Closure Equation

The purpose of this paper is to investigate the properties of the coupler curves generated by all 3R2C linkages. First, the 3x3 matrix with dual elements is used to derive the loop closure equation, the displacement equations are derived, and all joints variables are expressed in terms of input and output variables. Then, the parametric equations of the coupler curve are found by the D-H matrix. Finally, homogeneous coordinate is introduced to those displacement equations, and the order and some critical properties of the coupler curve are investigated based on the theories of algebraic curve and analytical geometry of three dimensions. In addition, RCRCR and RRCCR linkages are used as examples for illustration. Moreover, the results on the application of dimensional synthesis are discussed.

A Generalized Loop-Closure Theory for the Analysis and Synthesis of Compliant Mechanisms

1994 ◽  
Author(s):  
Larry L. Howell ◽  
Ashok Midha
Keyword(s):  
Energy Storage ◽  
Rigid Body ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Mechanism Analysis ◽  
Model Concept ◽  
Loop Closure ◽  
Body Model ◽  
Rigid Body Model ◽  
Analysis And Synthesis

Abstract Compliant mechanisms gain at least some of their motion from flexible members. The combination of large-deflection beam analysis, kinematic motion analysis, and energy storage makes the analysis of compliant mechanisms difficult. The design of mechanisms often requires iteration between synthesis and analysis procedures. In general, the difficulty in analysis has limited the use of compliant mechanisms to applications where only simple functions and motions are required. The pseudo-rigid-body model concept promises to be the key to unifying the compliant and rigid-body mechanism theories. It simplifies compliant mechanism analysis by determining an equivalent rigid-body mechanism that accurately models the kinematic characteristics of a compliant mechanism. Once this model is obtained, many well known concepts from rigid-body mechanism theory become amenable for use to analyze and design compliant mechanisms. The pseudo-rigid-body-model concept is used to develop a generalized loop-closure method for the analysis and synthesis of compliant mechanisms. Synthesis is divided into two major categories: (i) rigid-body replacement synthesis, wherein only kinematic constraints are considered, and (ii) synthesis for compliance, wherein considerations of the energy storage and input/output force/torque characteristics of compliant mechanisms are utilized. The method allows compliant mechanisms to be designed for tasks that would have earlier been assumed to be unlikely, if not impossible, applications of compliant mechanisms. Examples of function, motion, and path generation of compliant mechanisms are presented for the first time.

A Unified Algorithm for Analysis and Simulation of Planar Four-Bar Motions Defined With R- and P-Joints

2014 ◽  
Author(s):  
Xiangyun Li ◽  
Xin Ge ◽  
Anurag Purwar ◽  
Q. J. Ge
Keyword(s):  
Linkage Analysis ◽  
Least Squares ◽  
Efficient Algorithm ◽  
Image Space ◽  
Loop Closure ◽  
Closure Equation ◽  
Unified Algorithm ◽  
Four Bar Linkage ◽  
Best Fit ◽  
Linkage Synthesis

This paper presents a single, unified and efficient algorithm for animating the motions of the coupler of all four-bar mechanisms formed with revolute (R) and prismatic (P) joints. This is achieved without having to formulate and solve the loop closure equation associated with each type of four-bar linkages separately. In our previous paper on four-bar linkage synthesis, we map the planar displacements from Cartesian to image space using planar quaternion. Given a set of image points that represent planar displacements, the problem of synthesizing a planar four-bar linkage is reduced to finding a pencil of Generalized- or G-manifolds that best fit the image points in the least squares sense. The three planar dyads associated with Generalized G-manifolds are RR, PR and RP which could construct six types of four-bar mechanisms. In this paper, we show that the same unified formulation for linkage synthesis leads to a unified algorithm for linkage analysis and simulation as well. Both the unified synthesis and analysis algorithms have been implemented on Apple’s iOS platform.

Estimation of Location and Orientation From Range Measurements

2015 ◽  
Author(s):  
Sai Krishna Kanth Hari ◽  
Swaroop Darbha
Keyword(s):  
Linear Programming ◽  
Rigid Body ◽  
Center Of Mass ◽  
Body Motion ◽  
Second Step ◽  
True Distance ◽  
Numerical Examples ◽  
Range Measurements ◽  
Motion Constraints

Localization is an important required task for enabling vehicle autonomy. Localization entails the determination of the position of the center of mass and orientation of a vehicle from the available measurements. In this paper, we focus on localization by using the range measurements available to a vehicle from the communication of its multiple onboard receivers with roadside beacons. The model proposed for measurement is as follows: the true distance between a receiver and a beacon is at most equal to a predetermined function of the range measurement. The proposed procedure for localization is as follows: Based on the range measurements specific to a receiver from the beacons, a finite LP (linear programming) is proposed to estimate the location of the receiver. The estimate is essentially the Chebychev center of the set of possible locations of the receiver. In the second step, the location estimates of the vehicle are corrected using rigid body motion constraints and the orientation of the rigid body is thus determined. Two numerical examples provided at the end corroborate the procedures developed in this paper.

Optimal Non-Uniform Parametrization for Fourier Descriptor Based Path Synthesis of Four Bar Mechanisms

2018 ◽  
Author(s):  
Shashank Sharma ◽  
Anurag Purwar ◽  
Q. Jeffrey Ge
Keyword(s):  
Input Data ◽  
Design Space ◽  
Fourier Descriptors ◽  
Fourier Descriptor ◽  
Loop Closure ◽  
The Core ◽  
Closure Equation ◽  
Harmonic Decomposition ◽  
Path Synthesis

Fourier descriptor based path synthesis algorithms rely on harmonic decomposition of four-bar loop closure equation to split the design space into smaller subsets. The core of the methodology depends on calculation and fitting of Fourier descriptors. However, a uniform time parametrization is assumed in existing literature. This paper aims to explore the use of non-uniform time parametrization of input data and calculation of an optimal parametrization. Additionally, design-centric constraints have been proposed to give user enhanced control over coupler speed. As a result, this work improves the existing algorithm tremendously.

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