乘性故障对开闭环系统故障诊断性能的影响

Effects of multiplicative actuator faults on the fault diagnosis performance in open-loop and closed-loop systems

研究线性系统中执行器乘性故障分别对于开闭环系统故障诊断的影响。真实系统由于稳定性、鲁棒性等要求通常受到控制信号的作用。在执行器发生故障时,控制信号与残差信号无法完全解耦,故障幅值也会不可避免的对故障诊断性能带来影响。建立线性离散系统中执行器乘性故障模型,采用Luenburger观测器方法生成残差,通过分析故障情况下系统残差的一步转移方程递推表达式,研究开闭环系统中故障情况下估计误差信号和残差信号的动态演化规律。利用三角不等式得到开闭环情况下残差信号发散和收敛的条件,该条件与乘性故障的不同幅值紧密相关。仿真试验中通过选取不同幅值的执行器乘性故障说明该分析的有效性。

The effects of multiplicative actuator faults on the fault diagnosis performance in both open-loop and closed- loop systems were investigated. Practical systems were usually subject to control inputs owing to the stability and robustness requirements. When multiplicative actuator faults were encountered, control signals could not be completely decoupied from the residual signals and the faults would unavoidably influence the fault diagnosis performance. The actuator faults were modeled for linear discrete systems and the Luenburger observer was used to generate the residual signals. By studying the one-step state transfer equation and the triangle inequality, the dynamics of the estimation error and residual was discussed and the conditions under which the open-loop and closed-loop residuals were bounded were established which were dependent on the amplitudes of the possible faults. Some numerical examples were provided to show the effectiveness of the proposed analysis for actuator faults with different amplitudes.