Changzhi Ren

One Arc PMSM for telescope tracking system

This paper explores one Arc PMSM for Direct Drive Telescope tracking system. By the Arc PMSM, we can very easily manufacture one direct drive system for large telescope. Direct drive system has many advantages over more traditionally used friction and rack/pinion drive. The advantages include high stiffness, no friction, easy alignment and low maintenance. The paper discusses the design process of the Arc PMSM, especially the methods to reduce the torque ripple.

One direct drive system for Telescope

The paper discusses one direct drive telescope experiment bed (DDTEB), which is designed to simulate the modern telescope tracking system. The main task is to find the problem and the reliability which might be met in the real direct drive tracking system of the telescope and how to handle them. More information and experience will be acquired and accumulated to use the direct drive technology in the telescope complex motion system of Chinese telescope in the future.

The key technology of large telescope tracking system based on integrated super-low speed bearingless motor

With the continuous exploration of the universe and astronomy’s development, the telescopes are bigger and bigger. Horizon structure is widely used in the modern large telescopes rack, which carries dozens, even thousands of tons of the rotary parts and demands high accuracy and good stability. Therefore, it is one of the key technologies for large telescope to develop the precision support technology integrated direct drive with large load, high stiffness, low friction, even frictionless. Magnetic suspension bearing has not only the advantage of non-contact, no friction, high rigidity, high precision, low power, low mechanical assembly requirements, but also is integrated with the driven torque motor, which simplifies the structure, reduces the cost. This paper explores one kind of active bias magnetic suspension bearing integrated with direct drive technology based on multidisciplinary design optimization (MDO), which provides a new choice and view for the modern large astronomical telescope tracking system.

Design of one large telescope direct drive control system based on TMS320F28xx

The mount drive control is the key technique which mostly affects astronomical telescope’s resolution and its speed. However, the ultra -lower speed and the giant moment of inertia make it very difficult to be controlled. In this paper, one segmented permanent-magnet synchronous motor (PMSM), 4m diameter, is suggested for the mount driving. A method is presented to drive the motor directly, which is based on TMS320F28XX and Insulated Gate Bipolar Transistor (IGBT) , also, HEIDENHAIN tape is used to detect the absolute position of the motor together with the Hall sensor. The segmented PMSM can work stable and the mount drive can realize nice tracking performance at ultra -lower speed with this drive system.

Integration and commissioning of the China SONG Telescope Tracking System

China SONG telescope would achieve the goal for long time continuous, uninterrupted, full automatic observation and works in the diffraction limit condition, whats more, it must realize 0.3 arc second tracking precision without guide star. This paper describes the integration and fine-tuning of the China SONG Drive Systems. It discusses the different problems encountered during the integration and commissioning. The servo model that was used to simulate the problems and to find new solutions is described as well as test results and advanced analysis methods.

Research on large aperture telescope drive control technology

The direct drive motor of large aperture telescope, integrated with the telescope mechanic structure, has characteristics of high load torque and large moment of inertia. The control method of drive system should be specially designed for the heavy load. This article aims to list the key issues of engineering technology applied to large aperture telescope. Drive control architecture and method, as well as design requirements of segmented direct drive motor on large astronomic telescope, are discussed in this article.

Optics Derotator Servo Control System for SONG Telescope

The Stellar Oscillations Network Group (SONG) is an initiative which aims at designing and building a groundbased network of 1m telescopes dedicated to the study of phenomena occurring in the time domain. Chinese standard node of SONG is an Alt-Az Telescope of F/37 with 1m diameter. Optics derotator control system of SONG telescope adopts the development model of Industrial Computer + UMAC Motion Controller + Servo Motor.1 Industrial computer is the core processing part of the motion control, motion control card(UMAC) is in charge of the details on the motion control, Servo amplifier accepts the control commands from UMAC, and drives the servo motor. The position feedback information comes from the encoder, to form a closed loop control system. This paper describes in detail hardware design and software design for the optics derotator servo control system. In terms of hardware design, the principle, structure, and control algorithm of servo system based on optics derotator are analyzed and explored. In terms of software design, the paper proposes the architecture of the system software based on Object-Oriented Programming.

China SONG telescope tracking system based on direct drive technology

SONG (Stellar Oscillations Network Group) is a Danish initiative to design and build a global network of 1-m class telescopes. The plan is to design and build a global network of small telescopes located at 8 existing observatories around the world. The scientific goals of SONG need to obtain long-term and continuous observations (weeks to months). The group behind the SONG proposal has devised a new and innovative concept to overcome these problems in a cost-effective way. China, as one of the eight sites, its 1-m class telescope can achieve the goal for long time continuous, uninterrupted, full automatic observation and works in the diffraction limit condition. At the same time the telescope must realize 0.3 arc second tracking precision without guide star, which is a very challenge and difficult task for 1 meter telescope tracking system .This paper discusses the design and analysis of Chinese song telescope control system,ecpecially, its tracking system .

Introduction of Chinese SONG telescope

SONG (Stellar Oscillation Network Group) is an international project to form a global observing network of eight 1- meter class telescopes. China joined this project and funded one node telescope for this network. By the end of 2013, the Chinese SONG telescope has been installed on the Delinha observing site of Purple Mountain Observatory in Qinghai province. This paper will give the introduction of this telescope, including its optical system, structure and control system. Besides, the preliminary observing performance of the telescope on site will be given in the second part of this paper.