船舶螺旋桨推力的在线高精度辨识方法

Online high-precision identification method for ship propeller thrust

  • 摘要:
    目的 螺旋桨推力在轴系上产生的微弱形变信号易被干扰噪声所淹没,导致难以准确测量其推力,故提出一种在低信噪比下仍具有很高精度的螺旋桨推力测量方法。
    方法 综合考虑测量数据误差的影响以及数据中潜藏的力学机制,基于Kalman滤波结合推力–位移状态方程建立轴系推力辨识模型,并以恒定转速、变转速及低频波动转速3种工况为例开展轴系推力测量研究,分析不同信噪比下该方法的推力辨识精度与鲁棒性。
    结果 研究结果表明,当信噪比仅为20 dB时,推力辨识的最大相对误差仅为3.56%,验证了其在低信噪比下的高精度辨识能力与鲁棒性。
    结论 研究成果可为实船环境下螺旋桨推力及轴系状态的在线实时高精度监测提供参考。

     

    Abstract:
    Objective The weak deformation signal generated by propeller thrust on a shaft system is easily overshadowed by interfering noise, making it challenging to accurately measure the thrust. Therefore, this study proposes a new method for accurately measuring the thrust of propellers under low signal-to-noise ratio conditions.
    Methods By taking into consideration the influence of measurement data errors and the underlying mechanical mechanisms, a thrust identification model is established based on a combination of Kalman filtering, and the thrust-displacement state equation. Thrust measurement research is conducted under three different operating conditions: constant rotational speed, variable rotational speed and low-frequency fluctuating rotational speed. The precision and robustness of the proposed method are then analyzed under different signal-to-noise ratios.
    Results The results demonstrate that even at a signal-to-noise ratio of only 20 dB, the maxi-mum relative error in thrust identification is only 3.56%. Thus, the proposed method exhibits highly accurate and robust thrust identification performance under low signal-to-noise ratio conditions.
    Conclusion  The findings of this study can provide valuable insights for the real-time and high-precision monitoring of propeller thrust and shaft system status in actual ship environments.

     

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