The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees...The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.展开更多
Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were...Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.展开更多
静态电压稳定性是一种理想化的稳定性概念,其扰动无限小的假设不利于强非线性的电力系统在静态电压稳定域(steady-state voltage stability region,SVSR)内的安全运行。针对功率大扰动场景下由SVSR内的边界危机所引发的吸引域骤缩问题,...静态电压稳定性是一种理想化的稳定性概念,其扰动无限小的假设不利于强非线性的电力系统在静态电压稳定域(steady-state voltage stability region,SVSR)内的安全运行。针对功率大扰动场景下由SVSR内的边界危机所引发的吸引域骤缩问题,提出了一种考虑边界危机的电压稳定域(voltage stability region considering boundary crises,BCVSR)的划分方法。首先通过流形分析研究了边界危机的发生机理及其对电压稳定性的影响。其次通过相轨迹分析验证了理论研究的结果。然后通过分岔分析研究了参数变化对直驱风电并网系统的平衡集及动态特性的影响。最后划分了系统在注入功率空间中的单参数与双参数BCVSR,并将其与SVSR进行了对比。研究结果表明,在考虑功率大扰动的情形下,BCVSR的划分排除了SVSR内的边界危机对系统电压稳定性的威胁,有助于指导电力系统在实际运行中的功率调整。展开更多
基金Project(2013ZX04008011)supported by the National Science and Technology Major Projects of ChinaProject(51675100)supported by the National Natural Science Foundation of China
文摘The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.
基金Project(51075350)supported by the National Natural Science Foundation of China
文摘Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.
文摘静态电压稳定性是一种理想化的稳定性概念,其扰动无限小的假设不利于强非线性的电力系统在静态电压稳定域(steady-state voltage stability region,SVSR)内的安全运行。针对功率大扰动场景下由SVSR内的边界危机所引发的吸引域骤缩问题,提出了一种考虑边界危机的电压稳定域(voltage stability region considering boundary crises,BCVSR)的划分方法。首先通过流形分析研究了边界危机的发生机理及其对电压稳定性的影响。其次通过相轨迹分析验证了理论研究的结果。然后通过分岔分析研究了参数变化对直驱风电并网系统的平衡集及动态特性的影响。最后划分了系统在注入功率空间中的单参数与双参数BCVSR,并将其与SVSR进行了对比。研究结果表明,在考虑功率大扰动的情形下,BCVSR的划分排除了SVSR内的边界危机对系统电压稳定性的威胁,有助于指导电力系统在实际运行中的功率调整。
