【目的】获得超细碳酸钙准确的仿真模型参数,实现超细碳酸钙的可靠仿真研究。【方法】将超细碳酸钙精简为软质球形粒子,使用颗粒接触缩放原理与量纲分析进行颗粒缩放,采用Hertz-Mindlin with JKR接触模型,结合物理实验和离散元软件EDEM...【目的】获得超细碳酸钙准确的仿真模型参数,实现超细碳酸钙的可靠仿真研究。【方法】将超细碳酸钙精简为软质球形粒子,使用颗粒接触缩放原理与量纲分析进行颗粒缩放,采用Hertz-Mindlin with JKR接触模型,结合物理实验和离散元软件EDEM仿真实验对超细碳酸钙的静态和动态休止角进行接触参数标定。首先利用单因素实验排除对静态和动态休止角影响不显著的参数。采用Box-Behnken实验搭建静态和动态的休止角和显著性参数之间的回归模型。将实际测定的静态和动态休止角作为响应值,进而对静态和动态休止角回归模型求解获得最佳的仿真参数组合,并对得到的仿真参数进行物理实验验证。【结果】得到显著性参数的最佳组合为:超细碳酸钙-超细碳酸钙静摩擦系数和滚动摩擦系数为0.36、0.31,超细碳酸钙-不锈钢静摩擦系数和滚动摩擦系数为0.38、0.22,离散元仿真实验所得到的静态动态休止角分别为42.5°和61.3°,与实测值的误差分别为0.96%和1.32%,无明显差异。【结论】参数标定后的接触参数能够应用于超细碳酸钙离散元仿真。展开更多
Addressing the impact of capacitor mismatch on the conversion accuracy of successive approximation register analog-to-digital converter(SAR ADC),a 12-bit 1 MS/s sub-binary SAR ADC designed using variable step size dig...Addressing the impact of capacitor mismatch on the conversion accuracy of successive approximation register analog-to-digital converter(SAR ADC),a 12-bit 1 MS/s sub-binary SAR ADC designed using variable step size digital calibration was proposed.The least mean square(LMS)calibration algorithm was employed with a ramp signal used as the calibration input.Weight errors,extracted under injected disturbances,underwent iterative training to optimize weight values.To address the trade-off between conversion accuracy and speed caused by a fixed step size,a novel variable step size algorithm tailored for SAR ADC calibration was proposed.The core circuit and layout of the SAR ADC were implemented using the Taiwan Semiconductor Manufacturing Company(TSMC)0.35μm complementary metal-oxide-semiconductor(CMOS)commercial process.Simulation of the SAR ADC calibration algorithm was conducted using Simulink,demonstrating quick convergence and meeting conversion accuracy requirements compared to fixed step size simulation.The results indicated that the convergence speed of the LMS digital calibration algorithm with variable step size was approximately eight times faster than that with a fixed step size,also yielding a lower mean square error(MSE).After calibration,the simulation results for the SAR ADC exhibited an effective number of bit(ENOB)of 11.79 bit and a signal-to-noise and distortion ratio(SNDR)of 72.72 dB,signifying a notable enhancement in the SAR ADC performance.展开更多
文摘【目的】获得超细碳酸钙准确的仿真模型参数,实现超细碳酸钙的可靠仿真研究。【方法】将超细碳酸钙精简为软质球形粒子,使用颗粒接触缩放原理与量纲分析进行颗粒缩放,采用Hertz-Mindlin with JKR接触模型,结合物理实验和离散元软件EDEM仿真实验对超细碳酸钙的静态和动态休止角进行接触参数标定。首先利用单因素实验排除对静态和动态休止角影响不显著的参数。采用Box-Behnken实验搭建静态和动态的休止角和显著性参数之间的回归模型。将实际测定的静态和动态休止角作为响应值,进而对静态和动态休止角回归模型求解获得最佳的仿真参数组合,并对得到的仿真参数进行物理实验验证。【结果】得到显著性参数的最佳组合为:超细碳酸钙-超细碳酸钙静摩擦系数和滚动摩擦系数为0.36、0.31,超细碳酸钙-不锈钢静摩擦系数和滚动摩擦系数为0.38、0.22,离散元仿真实验所得到的静态动态休止角分别为42.5°和61.3°,与实测值的误差分别为0.96%和1.32%,无明显差异。【结论】参数标定后的接触参数能够应用于超细碳酸钙离散元仿真。
基金the Natural Science Basic Research Project of Shaanxi Province,China(2020JM-583)。
文摘Addressing the impact of capacitor mismatch on the conversion accuracy of successive approximation register analog-to-digital converter(SAR ADC),a 12-bit 1 MS/s sub-binary SAR ADC designed using variable step size digital calibration was proposed.The least mean square(LMS)calibration algorithm was employed with a ramp signal used as the calibration input.Weight errors,extracted under injected disturbances,underwent iterative training to optimize weight values.To address the trade-off between conversion accuracy and speed caused by a fixed step size,a novel variable step size algorithm tailored for SAR ADC calibration was proposed.The core circuit and layout of the SAR ADC were implemented using the Taiwan Semiconductor Manufacturing Company(TSMC)0.35μm complementary metal-oxide-semiconductor(CMOS)commercial process.Simulation of the SAR ADC calibration algorithm was conducted using Simulink,demonstrating quick convergence and meeting conversion accuracy requirements compared to fixed step size simulation.The results indicated that the convergence speed of the LMS digital calibration algorithm with variable step size was approximately eight times faster than that with a fixed step size,also yielding a lower mean square error(MSE).After calibration,the simulation results for the SAR ADC exhibited an effective number of bit(ENOB)of 11.79 bit and a signal-to-noise and distortion ratio(SNDR)of 72.72 dB,signifying a notable enhancement in the SAR ADC performance.
