The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodica...The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodically time-varying mesh stiffness, the nonlinear tooth backlash, the lump-parameter model of the gear system is developed with one rotational and two translational freedoms of each gear. The eigen-values and eigenvectors are derived and analyzed on the basis of the real modal theory. The sensitivities of natural frequencies to design parameters including supporting and meshing stiffnesses, gear masses, and moments of inertia by the direct differential method are also calculated. The results show the quantitative and qualitative impact of the parameters to the natural characteristics of the gear system. Furthermore, the periodic steady state solutions are obtained by the numerical approach based on the nonlinear model. These results are employed to gain insights into the primary controlling parameters, to forecast the severity of the dynamic response, and to assess the acceptability of the gear design.展开更多
为了克服VFC(vector field convolution)Snake模型对图像弱边界的泄露问题,对其作了两点改进:a)重新定义了向量场核的模,有效降低了VFC外力对向量模参数的敏感性;b)综合利用VFC外力和图像势能力,给出动态VFC外力。随着模型曲线的形变,...为了克服VFC(vector field convolution)Snake模型对图像弱边界的泄露问题,对其作了两点改进:a)重新定义了向量场核的模,有效降低了VFC外力对向量模参数的敏感性;b)综合利用VFC外力和图像势能力,给出动态VFC外力。随着模型曲线的形变,不断调整外力,使得曲线精确定位到目标边界上。最后通过实验证明了改进后的VFC Snake模型对噪声具有鲁棒性、对参数变化不敏感,且能够收敛到图像弱边界处。展开更多
文摘The dynamic transmission characteristics and the sensitivities of the three stage idler gear system of the new NC power turret are studied in the paper. Considering the strongly nonlinear factors such as the periodically time-varying mesh stiffness, the nonlinear tooth backlash, the lump-parameter model of the gear system is developed with one rotational and two translational freedoms of each gear. The eigen-values and eigenvectors are derived and analyzed on the basis of the real modal theory. The sensitivities of natural frequencies to design parameters including supporting and meshing stiffnesses, gear masses, and moments of inertia by the direct differential method are also calculated. The results show the quantitative and qualitative impact of the parameters to the natural characteristics of the gear system. Furthermore, the periodic steady state solutions are obtained by the numerical approach based on the nonlinear model. These results are employed to gain insights into the primary controlling parameters, to forecast the severity of the dynamic response, and to assess the acceptability of the gear design.
文摘为了克服VFC(vector field convolution)Snake模型对图像弱边界的泄露问题,对其作了两点改进:a)重新定义了向量场核的模,有效降低了VFC外力对向量模参数的敏感性;b)综合利用VFC外力和图像势能力,给出动态VFC外力。随着模型曲线的形变,不断调整外力,使得曲线精确定位到目标边界上。最后通过实验证明了改进后的VFC Snake模型对噪声具有鲁棒性、对参数变化不敏感,且能够收敛到图像弱边界处。
