Modeling And Control Method Research Of Electro-hydraulic Direct Drive Rotary Vane Gear

The heading of a ship mainly depends on the rudder. The performance of the steering gear influences the maneuverability of a ship and also has great significance to the economy and safety in navigation of a ship. The Electro-hydraulic Direct Drive Rotary Vane Steering Gear is the combination of the direct drive volume control technology of hydraulic system and the rotary vane steering gear. It possesses the advantages of high energy efficiency, sample structure and low pollution of the direct drive volume control hydraulic system and advantages of good torque performance, compact structure and modularization of the rotary vane steering gear. It is promising in application.The principle and the structure of the Electro-hydraulic Direct Drive Rotary Vane Steering Gear are researched in this paper. The structure of the system is analysed and the simulation of the response characteristic of the system is carried out according to the characteristics of the system. Because the control to the steering gear is implemented though the servo electric motor, the performance of the electric motor has great significance in the performance of the steering gear. The method of using the expert PID control theory to solve the control problem of the system is put forward.The vector control theory of the induction motor and the close loop of speed are employed according to the performance requirement of the system, which makes it possible to follow the input command precisely.The hydrodynamic load of the steering gear system is analyed. The calculating method of the hydrodynamic load when rudder is static is studied and the hydrodynamic load of a balanced rudder is calculated which provides some references to the research of low speed steering gear. The hydrodynamic load is also studied according to reference papers when the rudder moving with a high speed or stop from a high speed.The mathematical model of the steering gear system is established, and the simulation is carried out to validate the performance of the motor and the steering gear system. The response characteristic and the precision of the system is analysed based on results of simulation.An integral separated PID controller is employed to solve the problem caused by the saturation nonlinearity of the motor and the interior leakage of steering gear. The PID controller is robust to the varation of the model and the parameters. The speed of the steering gear is low, so the time cost by turning the rudder will be long. This will course over turning and shaking. The integral separated PID controller will integrate the error when the error is large, and do not integrate if the error is small than the set value. The simulation is carried out.The results of simulations show that the over turning is reduced and the precision of the system is increased benefited from the integral separated PID controller.