两栖车辆非线性横摇阻尼系数估计

Estimated nonlinear damping coefficients of amphibious vehicle roll motion

为了估计两栖车辆非线性横摇阻尼系数,根据能量法提出了能量损耗函数概念,并根据两栖车辆自由横摇衰减曲线确定实验的能量损耗函数,再采用最小二乘法来确定非线性阻尼系数。为了考察该方法的有效性,通过数值仿真的方法生成模拟自由横摇衰减曲线,采用提出的方法预报了不同初始条件下的阻尼系数,最后根据两栖车辆的自由横摇衰减曲线,估计了平方型的阻尼系数。结果表明该方法精度高、操作简单,不但适用于小角度横摇,而且适用于大角度横摇。

An method was proposed to estimate the nonlinear damping coefficients of amphibious vehicle roll motion. The concept of roll energy decay function was put forward based on the Froude＇s energy method, and the energy decay function was determined via free rolling decay curve. And then the least square method was adopted to investigate the nonlinear damping coefficients. To inspect estimation accuracy of the proposed method, it is effective to use numerically simulated data that true value is known already, the highly precise damping coefficients was successfully obtained at different initial condition compared to true value. Finally, this method is applied to the tested roll decay curve of amphibious vehicle to identify the linear and quadratic damping coefficients. The obtained results show that this method is powerful, simply and valid to small and large amplitude ship rolling motion.