Unified mechanism synthesis method of a planar four-bar linkage for path generation employing a spring-connected arbitrarily sized rectangular block model

2013 ◽  
Vol 31 (3) ◽  
pp. 241-256 ◽  
Author(s):  
Bum Seok Kim ◽  
Hong Hee Yoo
Keyword(s):  
Synthesis Method ◽  
Path Generation ◽  
Block Model ◽  
Mechanism Synthesis ◽  
Rectangular Block ◽  
Four Bar Linkage

Synthesis of Rigid-Body Guidance Mechanism with Path and Pose Generation Independently

2014 ◽  
Vol 619 ◽  
pp. 115-120 ◽  
Author(s):  
Jing Shuai Liu ◽  
Song Lin
Keyword(s):  
Rigid Body ◽  
Synthesis Method ◽  
Kinematic Chain ◽  
Practical Method ◽  
Path Generation ◽  
Mechanism Synthesis ◽  
Link Mechanism ◽  
Combination Principle

This paper proposes a practical method for the synthesis of rigid-body guidance mechanism by dividing the guidance task into path and pose generation independently. As a first step, based on the mechanism combination principle, a basic four-bar mechanism for path generation is synthesized and a binary-link is combined to the mechanism for achieving the execute link’s poses, then the potential kinematic chain with ability to realize the desired coupler poses is selected from all of the combination possibilities. And then a strategy by fixing a Cam to the basic four-bar mechanism to control the linkage poses is also proposed. Finally, the Cam’s profile is synthesized and the combined cam-link mechanism is able to guide the coupler through all desired linkage positions. One example is presented to validate the proposed guidance mechanism synthesis method.

scholarly journals Mixed synthesis method of motion and path of planar four-bar linkages

2021 ◽  
Vol 12 (1) ◽  
pp. 443-449
Author(s):  
Rui Wu ◽  
Ruiqin Li ◽  
Hailong Liang ◽  
Fengping Ning
Keyword(s):  
Synthesis Method ◽  
Equation System ◽  
Optimal Combination ◽  
Synthesis Problem ◽  
Path Generation ◽  
Motion Synthesis ◽  
Filtering Algorithm ◽  
Four Bar Linkage

Abstract. The mixed synthesis of motion and path generation, which is also known as the Alt–Burmester problem, is an attractive problem for study. However, such a problem for the four-bar linkages which possess more than M poses (M>5) and mixed N path points has not been well-solved. In this work, a mixed synthesis method is developed for planar four-bar linkages to cope with the above problem. The developed method can quickly select an optimal combination that contains five poses and N points by using the conic filtering algorithm, which is based on the similar characteristics of the value and direction between the conic and coupler curves in a certain neighborhood. Next, the selected five poses are substituted into a simplified equation system of motion synthesis which includes four equations and four variables to solve the parameters of the planar four-bar linkage. Finally, a case is provided to validate the effectiveness of the developed method in the mixed synthesis problem.

Automatic Synthesis of a Planar Linkage Mechanism With Revolute Joints by Using Spring-Connected Rigid Block Models

2006 ◽  
Vol 129 (9) ◽  
pp. 930-940 ◽  
Author(s):  
Yoon Young Kim ◽  
Gang-Won Jang ◽  
Jung Hun Park ◽  
Jin Sub Hyun ◽  
Sang Jun Nam
Keyword(s):  
Minimization Problem ◽  
Synthesis Method ◽  
Synthesis Process ◽  
Rigid Block ◽  
Linkage Mechanism ◽  
Block Model ◽  
Mechanism Synthesis ◽  
Revolute Joints ◽  
Planar Linkage Mechanism ◽  
Linkage Model

In traditional linkage design practice, a designer first decides the specific linkage type, such as a four- or six-bar linkage, and then varies the joint locations and link lengths until the designer finds the desired linkage. The objective of this research is to establish an automatic mechanism synthesis method that determines the linkage type and dimensions during the synthesis process. The synthesis process can be formulated as a minimization problem. However, the process can be extremely difficult and time-consuming unless there is a single unified linkage model that represents any linkage mechanism without complicating kinematic analysis and allows the use of an efficient gradient-based optimizer. The main contribution of this investigation is to propose a unified planar linkage model consisting of rigid blocks connected by zero-length springs having real-valued variable stiffness. Stiffness controlling variables are the design variable of the minimization problem and a general planar linkage can be simulated by the spring-connected rigid block model if the stiffness value is chosen appropriately. Though mechanisms involving only revolute joints are investigated and the solved problems are relatively simple, the notion of the block model and the synthesis formulation in real variables are expected to give a different perspective on mechanism synthesis.

Synthesis and Balancing of Cam-Modulated Linkages

1987 ◽  
Author(s):  
P. Pracht ◽  
P. Minotti ◽  
M. Dahan
Keyword(s):  
Systematic Approach ◽  
Kinematic Chain ◽  
Path Generation ◽  
Industrial Manipulator ◽  
High Speeds ◽  
Structural Error ◽  
Mass Balancing ◽  
Four Bar Linkage ◽  
Robotic Applications ◽  
Class Of Functions

Abstract Linkages are inherently light, inexpensive, strong, adaptable to high speeds and have little friction. Moreover the class of functions suitable for linkage representation is large. For all these reasons numerous recent works deal with the problem of design mechanisms for robotic applications, but very often in terms of components such as gripper, transmission, balancing. We investigate a new application for linkages, using them to design industrial manipulator. The selected mechanism for this application is a four bar linkage with an adjustable lengh for exact path generation. This adjustment is performed by a track or cam which is substituted to a bar. By this mean, we define a cam-modulated linkage which possess superior accuracy potential and is capable of accomodating of industrial design restrictions. Such a kinematic chain is free from structural error for path generation and the presence of the track introduces the flexibility and versality in the usefull four bar chain. The synthesis technique of cam modulated linkage utilizes loop closure equations, envelop theory to find the centerline and the profile of the track. These techniques provide a systematic approach to the design of mechanism for path generation when extreme accuracy is required. In order to complete an contribution, we take in consideration the static balancing of the synthesized manipulator. To achieve static mass balancing we use the potential energy storage capabilities of linear springs, and integrated it with the non-linear motion of mechanism to provide an exact value of the desired counter loading functions. Examples are worked to demonstrate applications of these procedures and to illustrate the industrial potential of spring balancing and cam-modulated linkage.

Eliminating Structural Error in Real-Time Adjustable Four-Bar Path Generators Using Iterative Learning Control

2004 ◽  
Author(s):  
Hong-Jen Chen ◽  
Richard W. Longman ◽  
Meng-Sang Chew
Keyword(s):  
Control Systems ◽  
Real Time ◽  
Iterative Learning Control ◽  
Learning Control ◽  
Iterative Learning ◽  
Path Generation ◽  
Structural Error ◽  
Four Bar Linkage

Fundamental concepts of Iterative Learning Control (ILC) are applied to path generating problems in mechanisms. As an illustration to such class of problems, an adjustable four-bar linkage is used. The coupler point of a four-bar traces a coupler curve that will in general deviate from the desired coupler path. Except at the precision points, the coupler curve will exhibit some structural error, which is the deviation from the specified curve. The structural error will repeat itself every cycle at exactly the same points over the range of interest. Since ILC is a methodology that was developed to handle similar repetitive errors in control systems, it is believed that it will be well served to apply it to this class of problems. Results show that ILC can be simple to implement, and it is found to be very well suited for such path generation problems.

Mechanisms of the Ancient Greek Theater

1992 ◽  
Author(s):  
Andrew D. Dimarogonas
Keyword(s):  
The Political ◽  
Path Generation ◽  
Space Travel ◽  
Ancient Greek ◽  
Machine Element ◽  
Four Bar Linkage ◽  
Indirect Information ◽  
First Time ◽  
Latin Term

Abstract The word Mechanism is a derivative of the Greek word mechane (which meant machine, more precisely, machine element) meaning an assemblage of machines. While it was used for the first time by Homer in the Iliad to describe the political manipulation, it was used with its modern meaning first in Aeschylos times to describe the stage machine used to bring the gods or the heroes of the tragedy on stage, known with the Latin term Deus ex machina. At the same time, the word mechanopoios, meaning the machine maker or engineer, was introduced for the man who designed, built and operated the mechane. None of these machines, made of perishable materials, is extant. However, there are numerous references to such machines in extant tragedies or comedies and vase paintings from which they can be reconstructed: They were large mechanisms consisting of beams, wheels and ropes which could raise weights up-to one ton and, in some cases, move them back-and-forth violently to depict space travel, when the play demanded it. The vertical dimensions were over 4 m while the horizontal travel could be more than 8 m. They were well-balanced and they could be operated, with some exaggeration perhaps, by the finger of the engineer. There is indirect information about the timing of these mechanisms. During the loading and the motion there were specific lines of the chorus, from which we can infer the duration of the respective operation. The reconstructed mechane is a spatial three- or four-bar linkage designed for path generation.

Synthesis of the four-bar linkage as path generation by choosing the shape of the connecting rod

2020 ◽  
Vol 234 (13) ◽  
pp. 2643-2652 ◽  
Author(s):  
SM Varedi-Koulaei ◽  
H Rezagholizadeh
Keyword(s):  
Analytical Solution ◽  
Nonlinear Equations ◽  
Linear Equations ◽  
Solution Process ◽  
Current Method ◽  
Path Generation ◽  
Connecting Rod ◽  
Complicated Process ◽  
Four Bar Linkage ◽  
Analytical Synthesis

This paper presents a method for path generation synthesis of a four-bar linkage that includes both graphical and analytical synthesis and both cases of with and without prescribed timing. The advantage of the proposed method over available techniques is that it is easier and does not need the complicated process (especially in graphical case). In an analytical solution, this method needs the solution of the linear equations, unlike the previous methods, in that they have required the solution of the nonlinear equations. Moreover, in the current method, one can choose the shape of the coupler, while, in other methods, the shape of the coupler is the result of the solution process. The proposed algorithm can be used for path generation synthesizing of a four-bar linkage for three precision points.

Real Continuation Method and its Application in Kinematic Synthesis

2000 ◽  
Author(s):  
Liu Anxin ◽  
Yang Tingli
Keyword(s):  
High Efficiency ◽  
Continuation Method ◽  
Linear Equations ◽  
Path Generation ◽  
Kinematic Synthesis ◽  
Real Solutions ◽  
Non Linear ◽  
Four Bar Linkage ◽  
Non Linear Equations

Abstract Real continuation method for finding real solutions to non-linear equations is proposed. Synthesis of planar four-bar linkage for path generation with nine precision points is studied using this method. The proposed method has high efficiency and can best be used for solving synthesis problems.

Design of an Ackermann-type steering mechanism

2013 ◽  
Vol 227 (11) ◽  
pp. 2549-2562 ◽  
Author(s):  
Jing-Shan Zhao ◽  
Xiang Liu ◽  
Zhi-Jing Feng ◽  
Jian S Dai
Keyword(s):  
Mechanism Synthesis ◽  
Steering Mechanism ◽  
Noncircular Gears ◽  
Four Bar Linkage ◽  
Transition Curves ◽  
Kinematic Simulations

This article focuses on the synthesis of a steering mechanism that exactly meets the requirements of Ackermann steering geometry. It starts from reviewing of the four-bar linkage, then discusses the number of points that a common four-bar linkage could precisely trace at most. After pointing out the limits of a four-bar steering mechanism, this article investigates the turning geometry for steering wheels and proposes a steering mechanism with incomplete noncircular gears for vehicle by transforming the Ackermann criteria into the mechanism synthesis. The pitch curves, addendum curves, dedendum curves, tooth profiles and transition curves of the noncircular gears are formulated and designed. Kinematic simulations are executed to demonstrate the target of design.

Optimum Synthesis of Planar Mechanisms for Path Generation Based on a Combined Discrete Fourier Descriptor

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Wen-Yi Lin
Keyword(s):  
Synthesis Method ◽  
Optimization Method ◽  
Path Generation ◽  
Fourier Descriptor ◽  
Planar Mechanisms ◽  
Two Phase ◽  
Phase Synthesis ◽  
Optimum Synthesis ◽  
Centroid Distance ◽  
The One

A two-phase synthesis method is described, which is capable of solving quite challenging path generation problems. A combined discrete Fourier descriptor (FD) is proposed for shape optimization, and a geometric-based approach is used for the scale–rotation–translation synthesis. The combined discrete FD comprises three shape signatures, i.e., complex coordinates (CCs), centroid distance (CD), and triangular centroid area (TCA), which can capture greater similarity of shape. The genetic algorithm–differential evolution (GA–DE) optimization method is used to solve the optimization problem. The proposed two-phase synthesis method, based on the combined discrete FD, successfully solves the challenging path generation problems with a relatively small number of function evaluations. A more accurate path shape can be obtained using the combined FD than the one-phase synthesis method. The obtained coupler curves approximate the desired paths quite well.

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