Abstract:The problem of synthesizing a planar four-bar linkage with two given fixed pivots such that the coupler curve passes through five given points is considered with the Groebner-Sylvester hybrid approach. First, closedform equations of a single point are constructed. The reduced Groebner basis in degree lexicographic ordering for the closed-form equations is then obtained using computer algebra. A 23 6 23 Sylvester's matrix can be constructed by selecting 23 out of 89 Groebner bases. A 36th degree univariate equa… Show more
“…See Huang et al (2008) [10] for recent work on path synthesis for four-bar linkages. The use of four-bar linkage modules to constrain an nR serial chain extends the work by Soh and McCarthy [6,7], who use RR links to constrain nR serial chains.…”
This paper uses coupler-path synthesis to design four-bar linkage modules that constrains the movement of links in an nR serial chain. The goal is to formulate a general procedure for path-synthesis of a robotic system using four-bar linkages. A desired end-effector trajectory is transformed into a secondary trajectory that is used for nine-point synthesis of a constraining four-bar linkage. This procedure constrains an nR chain to become a 4n-2 bar linkage. An example presents the constraint of a 2R chain to a six-bar that has a prescribed trajectory for an end-effector point.
“…See Huang et al (2008) [10] for recent work on path synthesis for four-bar linkages. The use of four-bar linkage modules to constrain an nR serial chain extends the work by Soh and McCarthy [6,7], who use RR links to constrain nR serial chains.…”
This paper uses coupler-path synthesis to design four-bar linkage modules that constrains the movement of links in an nR serial chain. The goal is to formulate a general procedure for path-synthesis of a robotic system using four-bar linkages. A desired end-effector trajectory is transformed into a secondary trajectory that is used for nine-point synthesis of a constraining four-bar linkage. This procedure constrains an nR chain to become a 4n-2 bar linkage. An example presents the constraint of a 2R chain to a six-bar that has a prescribed trajectory for an end-effector point.
“…The last one is the topic related to our work. It is worth mentioning that the dimensional synthesis of a simple mechanism such as a four-bar mechanism is not a trivial task and can essentially be performed by graphical [19], algebraic [20], analytic [19], or optimization [21] methods. The first three methods are helpful for synthesizing four-bar mechanisms when the trajectories (paths) are relatively simple.…”
Section: Introductionmentioning
confidence: 99%
“…10] T , c2 = [17.66, 15.142] T , c3 = [11.736, 17.878] T , c4 = [5, 16.928] T , c5 = [0.60307, 12.736] T , c6 = [0.60307, 7.2638] T , c7 = [5, 3.0718] T , c8 = [11.736, 2.1215] T , c9 = [17.66, 4.8577] T , c10 =[20,10] …”
Mechanisms have allowed for the automation of complex, repetitive, demanding, or dangerous tasks for humans. Among the different mechanisms, those with a closed kinematic chain are more precise and robust compared to open chain ones, which makes them suitable for many applications. One of the most widely used closed-chain alternatives is the four-bar Grashof-type mechanism, as it can generate highly nonlinear closed trajectories with a single degree of freedom. However, the dimensional synthesis of these mechanisms to generate specific trajectories is a complex task. Fortunately, computational methods known as metaheuristics can solve such problems effectively. Differential Evolution (DE) is a metaheuristic commonly used to tackle the dimensional synthesis problem. This paper presents a comparative study of the most commonly used variants of DE in solving the dimensional synthesis problem of four-bar Grashof-type mechanisms. The purpose of the study is to provide guidelines to choose the best DE alternative for solving problems of this type, as well as to support the development of DE-based algorithms that can solve more specific cases effectively. After analysis, the rand/1/exp variant was found to be the most effective in solving the dimensional synthesis problem, which was followed by best/1/bin. Based on these results, a Simple and Improved DE (SIDE) variant based on these two was proposed. The competitive performance of the SIDE with respect to the studied DE variants and in contrast to the results of algorithms used in the recent specialized literature for mechanism synthesis illustrates the usefulness of the study.
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