International Review of Applied Engineering Research. ISSN 2248-9967 Volume 3, Number 1 (2013), pp. 37-44 © Research India Publications http://www.ripublication.com/iraer.htm Optimal Synthesis of Planar Eight-Bar Mechanism for Function Generation: A Variable Topology Approach *Dr. Shivanand G. Sarganachari and Dr.V. B. Math Dept. of Mechanical Engineering, Basaveshwar Engineering College, Bagalkot-587102, Karnataka, India *Corresponding author email:sgsarganachari@gmail.com Abstract An analytical method is developed for the synthesis of planar eight bar mechanism with variable topology. The method uses Freudenstein’s equation for three point function generation. The synthesis of eight bar mechanism involves three phases. Each phase comprises of a four bar mechanism. The output angular positions of the first phase are taken as the input angular positions of the second phase and the output angular positions of the second phase are taken as the input angular positions of the third phase. The transmission angle is maintained within the optimum limit. Also, the method is illustrated with an example. Keywords: Synthesis, Eight bar mechanism, Variable topology, Freudenstein’s equation. 1. Introduction The planar linkages have wide variety of applications in mechanical machineries. The algebraic methods for synthesis of planar four bar mechanism are based on the Freudenstein’s equation for function generation. The graphical methods for synthesis of planar mechanism are available in the works of J.C. Lindholm[1], and D.C.Tao[2]. F. Freudenstein[3] proposed an analytical method to design a four bar mechanism that yields loop equation. C.H. Suh and C.W. Radcliffe[4] uses a displacement matrix to solve nonlinear simultaneous equations for synthesis of planar linkages. Morgan and Wampler[5] describes the continuation method to solve simultaneous nonlinear equations. T.S. Todorov[6] proposed a method for dimensional synthesis of