Particle swarm optimization algorithm is a novel bionic, swarm intelligence optimization algorithm. The algorithm principle is simple, less need to adjust the parameters and convergence speed is fast and easy to implement, so in recent years, particle swarm optimization (pso) to cause the attention of many scholars. So far, however, the particle swarm algorithm are not mature in theory analysis and practice applications, there are still a lot of problems need further research. Based on particle swarm algorithm is prone to "premature" into a local minimum value problem to improve the standard particle swarm algorithm and improved particle swarm optimization (pso) algorithm was applied to BP neural network. This paper's main work is as follows: at first, this paper introduces the particle swarm algorithm in the general situation of the research status and development at home and abroad, systematically analyzes the basic theory of particle swarm optimization algorithm, summarizes the common improved particle swarm optimization algorithm. Secondly introduces the analysis method of Hooke - Jeeves pattern search algorithm, the basic process and application fields. In view of the standard particle swarm optimization algorithm "precocious" problems, easy to fall into local minimum value, in this paper, the standard particle swarm algorithm was improved. First of all, the original definition of the initial population is divided into two identical sub populations, based on the fitness of thought respectively each child population is divided into two subsets, and Pareto subset N_Pareto subset; And then has a better fitness of two subgroups of two Pareto set for the new population. Griewank and Rastrigin because of the new population parameter setting differs from the standard particle swarm algorithm of the parameter is set, the new particles and particle trajectories in the different standard population, population expanding, which makes the algorithm's global search ability have improved.
To balance the global search capability of the particle swarm algorithm and local optimization ability, and improve the precision and efficiency of particle swarm optimization (pso) algorithm, introduced in this article in the new population optimization process has a strong convergence ability to search method of Hooke - Jeeves, IMPSO algorithm is proposed. And standard benchmark test functions with IMPSO algorithm experiment, will receive the results with the standard particle swarm algorithm, comparing the experimental results of benchmark functions, the simulation results prove the validity of the improved particle swarm algorithm.
At the end of the paper research the improved particle swarm algorithm in the application of the BP neural network. First this paper introduces the principle of artificial neural network and based on the multi-layer feed-forward neural network BP algorithm, secondly by IMPSO algorithm training the BP neural network and training flow chart is given.
IMPSO algorithm training the BP neural network respectively used in the gear heat treatment hardening layer depth prediction and used for fault diagnosis of diesel engine cylinder head and cylinder wall, and the predicted results, the diagnostic results, the standard particle swarm optimization algorithm with BP neural network of training BP neural network, comparing the experimental results of the experimental results show that the improved particle swarm optimization (pso) training BP network has better optimization performance and learning ability.