Optimization design of multi-objective tolerances based on niche PSO algorithm

To solve the problem of tolerance optimization in product design, an optimization approach for multi-objective tolerance based on niche Particle Swarm Optimization (PSO) algorithm was proposed. By taking manufacturing cost, quality loss cost and tolerance sensibility as the design objectives, a multi-objective model of tolerance optimization was presented which were subject to the assembly functional requirement and the machining capability. The traditional particle swarm optimization was improved, and the outlier particle was identified by niche number and Pareto dominance of every particle, with which the mutation and selection operation of individual optimal particle and outlier particle were applied to update the optimal position for the particles. The global optimum of particle swarm was updated by Pareto dominance number. The Pareto front of uniform distribution was obtained by using niche PSO algorithm to solve the multi-objective model of tolerance optimization. A prototype system was developed and an example was tested to verify the feasibility of the proposed approach.