Scanning probe microscopes (SPM) are limited in their speed of data acquisition by the mechanical stability of the scanner. Therefore many types of scanners have been developed to achieve a rigid setup while maintaini...Scanning probe microscopes (SPM) are limited in their speed of data acquisition by the mechanical stability of the scanner. Therefore many types of scanners have been developed to achieve a rigid setup while maintaining an acceptable image size. We have followed here a different path to accelerate data acquisition by improving the feedback loop to achieve the same SPM image quality in a shorter time. While the feedback loop in a scanning probe microscope typically starts to probe a new pixel starting from the previous position, we have reduced the total control time by using an improved starting point for the feedback loop at each pixel. By exploiting the information of the already scanned pixels a forecast for the new pixel is created. We have successfully used several simple methods for a prognosis in MATLAB simulations like one dimensional linear or cubic extrapolation and others. Only scanning tunnelling microscope data from real experiments were used to test the forecasts. A doubling of the speed was achieved in the most favourable cases.展开更多
This paper focuses on the H∞ controller design for linear systems with time-varying delays and norm-bounded parameter perturbations in the system state and control/disturbance. On the existence of delayed/undelayed f...This paper focuses on the H∞ controller design for linear systems with time-varying delays and norm-bounded parameter perturbations in the system state and control/disturbance. On the existence of delayed/undelayed full state feedback controllers, we present a sufficient condition and give a design method in the form of Riccati equation. The controller can not only stabilize the time-delay system, but also make the H∞ norm of the closed-loop system be less than a given bound. This result practically generalizes the related results in current literature.展开更多
城市轨道交通系统中,地铁列车会频繁启停,在启动时会消耗大量电能,而在制动时产生的能量约占牵引能耗的40%。为了充分利用地铁制动能量及稳定直流接触网电压,高压大容量双向变流器得到广泛应用。RTDS (Real-time Digital Simulator)仿...城市轨道交通系统中,地铁列车会频繁启停,在启动时会消耗大量电能,而在制动时产生的能量约占牵引能耗的40%。为了充分利用地铁制动能量及稳定直流接触网电压,高压大容量双向变流器得到广泛应用。RTDS (Real-time Digital Simulator)仿真器是功能强大的实时数字仿真装置,通过建立高压大容量变流器的离散仿真模型、与实际控制设备连接形成半实物仿真系统,可实现系统动静态特性的实时模拟,从而大幅提高研发效率。本文建立了高压大容量双向变流器仿真模型,结合实际硬件控制器构建了硬件在环仿真系统,验证了控制器硬件及其搭载控制策略的有效性。展开更多
文摘Scanning probe microscopes (SPM) are limited in their speed of data acquisition by the mechanical stability of the scanner. Therefore many types of scanners have been developed to achieve a rigid setup while maintaining an acceptable image size. We have followed here a different path to accelerate data acquisition by improving the feedback loop to achieve the same SPM image quality in a shorter time. While the feedback loop in a scanning probe microscope typically starts to probe a new pixel starting from the previous position, we have reduced the total control time by using an improved starting point for the feedback loop at each pixel. By exploiting the information of the already scanned pixels a forecast for the new pixel is created. We have successfully used several simple methods for a prognosis in MATLAB simulations like one dimensional linear or cubic extrapolation and others. Only scanning tunnelling microscope data from real experiments were used to test the forecasts. A doubling of the speed was achieved in the most favourable cases.
基金This project was supported by the National Natural Science Foundation of China (No. 69974022).
文摘This paper focuses on the H∞ controller design for linear systems with time-varying delays and norm-bounded parameter perturbations in the system state and control/disturbance. On the existence of delayed/undelayed full state feedback controllers, we present a sufficient condition and give a design method in the form of Riccati equation. The controller can not only stabilize the time-delay system, but also make the H∞ norm of the closed-loop system be less than a given bound. This result practically generalizes the related results in current literature.
文摘城市轨道交通系统中,地铁列车会频繁启停,在启动时会消耗大量电能,而在制动时产生的能量约占牵引能耗的40%。为了充分利用地铁制动能量及稳定直流接触网电压,高压大容量双向变流器得到广泛应用。RTDS (Real-time Digital Simulator)仿真器是功能强大的实时数字仿真装置,通过建立高压大容量变流器的离散仿真模型、与实际控制设备连接形成半实物仿真系统,可实现系统动静态特性的实时模拟,从而大幅提高研发效率。本文建立了高压大容量双向变流器仿真模型,结合实际硬件控制器构建了硬件在环仿真系统,验证了控制器硬件及其搭载控制策略的有效性。
