Abstract:

n view of the requirement for stable discharge current during electromagnetic launch (EML) process, a multistage optimization strategy of discharge sequence based on improved particle swarm optimization (PSO) is proposed. According to the sequential discharge characteristics of pulsed forming network(PFN), the subdivision rules are given for dividing the EML process into multiple stages, and the optimization model is established. Then the whole optimization framework for the EML process is built. The average information of swarm is introduced into updating process of velocity, and an adaptive PSO with dynamically adjusting inertia weight is proposed. In this PSO, the inertia weight is adjusted according to the evolutionary state of current population with dynamical adaptability in the optimization process, which improves the global and local search capability in every stage. To overcome the defect of slow convergence for unreasonable value space, the method of reducing search space is used which increases the lower limit of the value range when the current shape is not stable in the new stage. Finally the strategy is applied to optimize the discharge sequence of PFN for an EML system, the results show that the current shape is very stable and a higher exit velocity is obtained.