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第 46 卷        罗瑶嘉,等: 基于变分模态分解处理的冲击波压力长短期记忆网络系统建模                                第 5 期


                         Fitness   Penalty factor α
                                   Preset number of modes K
                 0.015 057                       3 400   5       10 −1
                                                                               Natural frequency
                 0.015 056                                         −2
                                                 3 200           10
                 0.015 055                               4       10 −3
                Fitness  0.015 054               3 000 Penalty factor α  Preset number of modes K  Normalized p  10 −4  BLIMF 1
                                                                                               BLIMF 2
                 0.015 053
                                                                                               BLIMF 3
                                                 2 800
                 0.015 052                               3                                     Res
                                                 2 600           10 −5
                 0.015 051
                 0.015 050                       2 400   2       10 −6
                        0   2    4   6    8   10                    0   100  200  300  400      900  1 000
                                  Iteration                                        f/kHz
                     图 4    优化算法适应度随迭代过程的收敛趋势                       图 5    信号分解后各分量的幅频特性频谱
                    Fig. 4    Convergence trend of the optimizer’s fitness  Fig. 5    Amplitude-frequency characteristics spectra
                              across iteration steps                  of the decomposed signal components


                      1.0                    Response signal 1     1.0                    Response signal 1
                   p/kPa  0.5 0                                 p/kPa  0.5 0
                      −0.5                                        −0.5
                         0         10         20         30          0         10         20         30
                                       Time/ms                                     Time/ms
                      1.0                                          1.0
                                                   BLIMF 1                                     BLIMF 1
                   p/kPa  0.5 0                                 p/kPa  0.5 0
                      −0.5                                        −0.5
                         0         10         20         30          0         10         20         30
                                       Time/ms                                     Time/ms
                      0.2                          BLIMF 2         0.2                         BLIMF 2
                                                                   0.1
                      0.1
                   p/kPa  −0.1 0                                p/kPa  −0.1 0
                      −0.2                                        −0.2
                         0         10         20         30          0         10         20         30
                                       Time/ms                                     Time/ms
                      0.04                         BLIMF 3        0.04                         BLIMF 3
                      0.02
                                                                  0.02
                   p/kPa  −0.02 0                               p/kPa  −0.02 0
                     −0.04                                       −0.04
                         0         10         20         30          0         10         20         30
                                       Time/ms                                     Time/ms
                      0.4                              Res         0.2                             Res
                      0.2
                                                                   0.1
                   p/kPa  −0.2 0                                p/kPa  −0.1 0
                      −0.4                                        −0.2
                         0         10         20         30          0         10         20         30
                                       Time/ms                                     Time/ms
                        (a) Decomposed modes of response signal 1   (b) Decomposed modes of response signal 2
                                               图 6    信号分解后各分量的时域特性
                                   Fig. 6    Time-domain characteristics of the decomposed signal components

                   实际环境中,使用正弦信号发生器可以测量出采集系统的低频段正弦信号幅值效率                                      [18] ,求得系统的
               低频段传递函数,因此在仿真中假定式中的低频段离散传递函数                            H(z) 已知。根据上述分析,可得重构信号:
                                                                        l
                                                         ß             ™
                                                           Z{F 1 (t)+r(t)}
                                                        −1
                                                 ˆ p(t) = Z                                            (23)
                                                               H l (z)
               补偿结果如图      7  所示。



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