International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 05 | May -2017 www.irjet.net p-ISSN: 2395-0072 © 2017, IRJET | Impact Factor value: 5.181 | ISO 9001:2008 Certified Journal | Page 1521 Review of Synthesis of Four BAR Mechanism Siddharth Shete 1 , Nitesh Kumar 2 , Praphulla Nalawade 3 , Prakash Tripathi 4 Assistant Professor, Dept. of Mechanical Engineering, Dr. D Y Patil Institute of Engineering, Management & Research, Akurdi, Pune, Maharashtra, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - This Paper briefly covers some commonly used graphical and analytical techniques and also different optimization algorithms. This is to review the important aspects which are essentially required in the analysis throughout. The methods are briefly reviewed as they are selectively used to cross verify the results of the proposed algorithm. Key Words: Graphical Methods, Two Position Synthesis, Three Position Synthesis, Objective Function, Evolutionary Algorithm. 1. GRAPHICAL METHODS FOR DIMENSIONAL SYNTHESIS This method [8] is employed in the path generation problem. The path generation problem is one of the type or subset of motion generation problem. In the path generation problem certain points are prescribed for successive motion of coupler link, these points are known as a precision points. The basic path synthesis starts with two precision positions. This type of synthesis is used to solve up to four precision positions. The methodology for two position synthesis is given below. 1.1 Two position synthesis The objective is to move a crank from point A1 to A2 so that output link should move from point B1 to B2 as shown in Fig -1. To achieve this objective following geometrical method is used. Fig -1: Two Position Synthesis The construction lines are drawn to connect A1 to A2 and B1 to B2. The lines A1A2 and B1B2 are then bisected and extended in the convenient directions as shown. Then O2 & O4 are conveniently selected as fixed pivots. The link 2 is O2 connected with A1 and the link 4 is O4 connected to B1. The line A1B1 is link-3, while O2O4 is link 1. 1.2 Three position synthesis The objective is to move a crank through three points A1, A2 and A3 so that output link should move through points B1, B2 and B3 as shown in Fig -2. To achieve this objective following geometrical method is used. Fig -2: Three Position Synthesis The construction lines are drawn to connect B2 to D and B3 to D. The line B2D is rotated through angle ϕ12 to get the point B2' and the line B3D is rotated through angle ϕ13 to get the point B3'. The lines B2B2' and B3B3' are then bisected and extended in the convenient directions as shown. The intersection point is C1. The lines are drawn to connect A to B1, B1 to C1 and C1 to D to form the four bar mechanism. The graphical procedure employed for the two-position synthesis problem can be extended up to the four position synthesis. As the number of precision points to be traced increases, the graphical method fails to give a correct solution.