Optimal Synthesis Of Planar 4-, 5-, And 6-bar Mechanisms Based On Particle Swarm Optimization Algorithms

Starting off from engineering application, a kinematic synthesis approach for planar 4-, 5-, and 6-bar mechanisms has been studied, based on research achievement in many fields, such as kinematic geometry of planar linkages, optimal method, and computation intelligence technique, et al. This paper presents the mathematical model and algorithm for planar inverted crank-slide mechanisms, 2-DOF 5-bar hybrid driven linkages, and Watt- and Stephenson-type 6-bar linkages.Particle swarm optimization (PSO) algorithm is a computation intelligence technique, inspired by social behavior of birds flocking. PSO algorithm possesses the advantages of simplified, rather quick convergence speed, global optimization performance, and less controlling parameters, et al. However, PSO algorithm has weak local searching abilities and be applied to solving complex optimal problems with high dimensions. Because of this weak, an improved PSO algorithm, hybrid algorithm of Powell method and particle swarm optimization (PPSO) is proposed. The hybrid algorithm can adopt lesser population, and decrease calculation scale, thus improves local searching abilities. Many classical testing functions of constrained optimization or unconstrained optimization to be taken as examples, experimental results show that the hybrid algorithm has excellent performance with higher accuracy and speed.The kinematic synthesis equations for RRR and RPRâ…¡groups have been established, respectively, based on the single-opened-chain (SOC) theory and displacement matrix method. Combining two kinematic synthesis equations for RRRâ…¡groups, this paper presents the unified kinematic synthesis equations for hinged 3-bar groups which are applied in function synthesis of planar Wattâ… , Stephensonâ…¡, andâ…¢6-bar linkages.The optimization models of approximate kinematic synthesis for rigid-body guidance, path generation, and function generation of inverted crank-slide mechanisms have been set up, according to kinematic synthesis equations of RRR and RPRâ…¡groups. Taking unified kinematic synthesis equations for hinged 3-bar groups as foundation, this paper puts forward the unified optimization models of function synthesis for Wattâ… , Stephensonâ…¡, andâ…¢6-bar linkages.For 2-DOF 5-bar hybrid driven hinged linkages,'two-step synthesis method'has been applied to study its path generation synthesis. Firstly, the optimization model for...