A Tutorial on Quantized Feedback Control

In this tutorial paper, we explore the field of quantized feedback control, which has gained significant attention due to the growing prevalence of networked control systems. These systems require the transmission of feedback information, such as measurements and control signals, over digital networks, presenting novel challenges in estimation and control design. Our examination encompasses various topics, including the minimal information needed for effective feedback control, the design of quantizers, strategies for quantized control design and estimation,achieving consensus control with quantized data, and the pursuit of high-precision tracking using quantized measurements.

A Precise Calibration Method on Phase Center of Uplink Antenna Array Considering Its Actual Pointing

With regard to the inferior techniques and low accuracy of phase center calibration of an antenna array, this paper proposes a new calibration method considering the actual antenna pointing by introducing a precise engineering surveying technique to measure the real state of antennas. First, an industrial photogrammetric system is utilized to obtain the coordinates of points on antenna panels in different postures, and the actual pointing of the mechanical axis is obtained via least-squares fitting. Then, based on this, the coordinates of antenna rotation center are obtained by seeking the intersection of mechanical axes via using the matrix method. Finally, the mechanical axis in arbitrary postures is estimated based on the inverse-angle weighting interpolation method, and the reliable phase center is obtained by moving a fixed length from the projective center along the mechanical axis. An uplink antenna array including three ? 3 m antennas is taken as experimental object, and all photogrammetric coordinate systems are unified by the engineering control network, with each antenna phase center precisely calibrated via the proposed method. The results of electrical signal synthesis indicate that this method can effectively overcome the influence of gravity deformation and mechanical installation error, and enhance the synthetic signal magnitude of the uplink antenna array.

Alignment technology of heavy ion medicalmachine

Background Heavy ion medical machine(HIMM)is built by the Institute of Modern Physics,Chinese Academy of Sciences,with a high-energy beam transport line with a height of 18 m,and its complex space mounting structure increases the difficulty of installation and alignment.Purpose The aim of this paper is to provide methods to install all accelerator components efficiently and to ensure that the alignment accuracies of all installed components are within the designed values.Methods We accomplished the fiducialization and pre-alignment of complex modules by combining the laser tracker and the alignment telescope.By analyzing various elements that affect the accuracy of alignment,a method of alignment for high-energy beam transport line was proposed based on high-precision three-dimensional control network.Results All components have been installed and aligned in a short time,alignment position accuracy of magnets is less than 0.1 mm,and the treatment components alignment accuracy is no more than 0.4 mm.Conclusions On the basis of error analysis,all alignment results are better than the required precisions,and all of these guaranteed the successful operation of HIMM.