Particle Swarm Optimization Arithmetic Research Articles

The Improved PSO Arithmetic for Identifying Ground Stress Based on Rock Core Discing Observation

Identifying ground stress based on rock core discing can save a lot of surveying cost, so studying “rock core disicing” has great meaning. Aiming at the limitation of conventional methods, the particle swarm optimization (PSO) arithmetic is introduced to be combined with numerical simulation, so as to identify the ground stress based on rock core disicing observation. The objective function of optimization is constructed by combing Mohr-Coulomb criterion and tension criterion. Adopts dynamically adjusting momentum term method and steric compression method so as to improve the PSO in convergence velocity and globally searching property. The proposed method is mentioned and used to identify the ground stress of Bakken formation in USA. The arithmetic has good convergence speed and the identified results are coincident with the former reported results.

Optimizing Supporting Parameters of Metro Tunnel Based on Improved Particle Swarm Optimization Arithmetic

The optimization of anchor and spay layer parameters of tunnel not only concerns the stability of surrounding rock, but also concerns the economic cost. Aiming to the implicit nonlinear relation between anchor parameters and surrounding rock stability, and the contradiction of stability object and economics object. The paper proposed a anchor parameters optimization method based on improved particle swarm optimization arithmetic and orthogonal designing scheme numerical test. The method firstly analyzed the sensibility of anchor parameters affecting surrounding rock stability and regressed function using numerical test data, then the limit displacement of surrounding rock is acted as the stability constraint condition and the cost function is as evaluation function, and the improved PSO is carried out. The method is used in metro tunnel of Dalian City of China, the result is good which states the method is feasible.

Analysis on oscillation in electro-hydraulic regulating system of steam turbine and fault diagnosis based on PSOBP

The oscillation in electro-hydraulic regulating system is one of the main reasons leading to the oscillation of electric power system. In this article the influence of internal leakage and plugging of servo valve on the characteristic of the regulating system was analyzed. With the simulation in AMESIM it was found that the leakage of the power stage spool, the plugging of nozzle and orifice could both cause the oscillation of regulating system when the system oil pressure fluctuated. The fluctuation of piston displacement and oil pressure in oil servo motor in different fault state were analyzed. For preventing regulating system from oscillation it was needed to diagnose fault in the servo valve. Taking single leakage for example the change of parameters such as regulating time, steady displacement, and system frequency response, etc. were analyzed. The characteristic table of different fault was given based on simulation. In diagnosis particle swarm optimization (PSO) arithmetic was combined with BP neural network. The weight and threshold values were optimized by PSO arithmetic and five characteristics such as the piston displacement and system frequency were selected as the input of network. The results show that the PSOBP arithmetic has quick convergence speed and good generalization ability, with which the diagnosis of fault in servo valve can be done effectively.