Coordinated Optimization Control Of Shield Machine Based On D-FNN Direct Inverse Control

With the continuous improvement of the country’s urbanization rate,the development of tunnel traffic and underground space has developed rapidly.In underground construction,shield construction method is widely used because of its high efficiency and safety.The earth pressure balance(EPB)shield is a special construction machine for underground excavation of underground tunnels.It is the main choice for tunnel construction because of its small impact on the surface environment and the construction is not restricted by the surface environment.The EPB shield maintains the stability of the excavation surface by controlling the earth pressure of the sealed cabin.If not controlled properly,it will cause surface uplift or settlement.But there is a strong nonlinear coupling relationship between various tunneling parameters.At the same time,the amount of soil entered and discharged from the sealed cabin can only be controlled according to the manual operation between the amount of soil entered and discharged,the accuracy of earth pressure balance control is reduced and the stability control effect of the excavation surface is poor.Therefore,a coordinated optimization control method of shield machine based on dynamic fuzzy neural network(D-FNN)direct inverse control is proposed.The cutter head torque,advancing speed,thrust,screw conveyor speed and earth pressure difference in the sealed cabin were used as inputs,and the D-FNN control model of the control parameters was established whose output were screw conveyor speed and advancing speed at next time.The error reduction rate method was used to trim and identify the network structure to optimize the control model.On this basis,an optimal control system for EPB of shield machine was established based on the direct inverse control method.The advancing speed and the screw conveyor speed are optimized,and tunneling control parameters with coordinated control characteristics are obtained.The simulation results show that the method can optimize the control parameters coordinately according to the changes in the construction environment,effectively reduce the earth pressure fluctuations during shield tunneling,and can better control the stability of the excavation surface.