基于LMI的H_∞滤波器在UUV纵倾控制中的应用

Numerical Simulation for the Pitch Control of UUV Based on H_∞ Filter and LMI Method

为实现无人水下航行器(UUV)在测量状态受外界干扰或不可量测时的纵倾控制,设计一种基于线性矩阵不等式(LMI)的H∞滤波器来估计状态量并进行纵倾控制。针对纵倾控制系统方程的系统矩阵在虚轴上存在极点的问题,利用特殊双线性变换方法对系统方程进行变换使之满足滤波器设计要求。针对UUV纵倾控制系统中部分测量状态受干扰而引起控制器输出振荡的问题,基于LMI为特殊双线性变换后的UUV纵倾控制系统设计了一个鲁棒H∞滤波器,再经过反变换得到所需的滤波器。该UUV纵倾控制系统的仿真结果表明,该滤波器能够消除测量噪声的影响,运动状态估计值准确并可提高UUV纵倾控制系统的控制品质。

To deal with the pitch control of UUV in the presence of measurement noise and the lack of state measurements, an Hoo filter is proposed to estimate related states in motion control using LMI method. A special bilinear transform method is introduced to overcome the issue that the system matrix of the pitch control equation has a pole on the imaginary axis, which does not meet the design requirements of filter. In order to eliminate the vibration of the stern elevator caused by disturbances of the states in the pitch control system, a robust filter is designed for the transformed system. Afterwards the required filter is obtained by inverse transformation. Simulation results demonstrate that the proposed filter, with an accurate estimation to the system states, is effective to eliminate the negative effects caused by measurement noise, and can enhance control quality.