船舶变频液压舵机控制策略研究

Study of Control Strategy for Marine Variable Frequency Hydraulic Steering Gear

针对船舶变频液压舵机系统存在控制死区、响应速度慢、负载影响大等特点,采用解析法与实验法相结合,获得变频液压舵机系统数学模型;采用死区补偿电压解决变频电机转速稳态误差问题;采用Z-N控制参数整定方法,确定变频电机转速PID控制参数初值。建立舵机液压模拟加载系统,实现水动力负载、周期性海浪负载和随机冲击负载的模拟。提出舵角控制采用分段控制策略,小偏差采用模糊自适应PID控制,控制算法中引入舵机负载变化因素。结果表明:该控制策略能有效抑制负载引起的舵角扰动,提高系统动态特性和鲁棒性,实现舵角快速、稳定的控制。

Aiming at the features such as control dead-zone, slow responding and great load disturbance of the marine variable frequency hydraulic steering gear, the theoretical and experimental analysis is adopted to obtain the mathematical model of the marine variable frequency hydraulic steering gear. The compensation voltage for the dead zone is adopted to eliminate the steady error for the motor speed. The preliminary PID parameters for the speed control of the variable frequency motor are obtained by means of Z-N method. The simulation loading hydraulic system for steering gear is set up, and the hydrodynamic load, the periodic sea wave load and the random shock load are achieved. The stage control strategy for the steering angle is put forward. The fuzzy adaptive PID algorithm is used when the deviation is small, and the factor representing the variation of the load is introduced to the control algorithm. The result shows that the rudder angle disturbances caused by the load are successfully restrained by which the dynamic characteristic and robustness are improved. The quick and stable control for the steering angle is achieved.