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.
The existing force actuators cannot work properly in the Antarctic under the condition of low temperature. In this paper,
a new design scheme of force actuator is put forward. Combined with the actual situation and the requirement of thin
mirror active optical experiment system, we design the force actuator structure which combined the active support and
passive support, and use a s-shaped load-cell to realize the force feedback controlling. Passive support part is responsible
for the adjustment of large travel with low precision, and active support part driven by PZT is responsible for the
adjustment with high accuracy. Finally, test was carried out through the open loop and closed loop experiment in low
temperature environment. The experimental results show that: The force actuator’s output force is 120 ~ 280N, the
accuracy is better than 0.05 N, meeting the requirement for the high precision under low temperature. The new kind of
force actuator can be applied to the active optical support system in the Antarctic, and at the same time can also be
applied to other structures of precision adjustment.
The 6-DOF parallel platform in this paper is a kind of Stewart platform. It can be used as supporting structure for telescope secondary mirror. In order to adapt the special dynamic environment of the telescope secondary mirror and to be installed in extremely narrow space, a unique parallel platform is designed. PSS Stewart platform and SPS Stewart platform are analyzed and compared. Then the PSS Stewart platform is chosen for detailed design. The virtual prototyping model of the parallel platform is built. The model is used for the analysis and calculation of multi-body dynamics. With the help of ANSYS, the finite element model of the platform is built and then the analysis is performed. According to the above analysis the experimental prototype of the platform is built.
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.
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 .
The 2.5m optical/infrared telescope is an F/8 telescope comprising one Cassegrain foci, two Nasmyth foci and two
student Nasmyth foci. This paper presents a brief description of the physical structure, conceptual design, hardware
implementing measure and software structure in the positioning control system of M<sub>2</sub>&M<sub>3</sub>. The graphical user interface
application (Qt) is adopted to design the software. During the full working range the M<sub>2</sub> focus and decenter achieve the
positioning repeatability is better than ±4μm and the M<sub>2</sub> tilt is better than 10 μrad. The M<sub>3</sub> angular positioning and
locking accuracy is better than 10 arcsec and repeatability is better than 2 arcsec RMS.
In recent years, Nanjing Institute of Astronomical Optics and Technology (NIAOT) has made several telescopes for
observatories all around the world. In 2011 NIAOT just finished the development of a 2.5m optical/infrared telescope
mount. First part of this paper is to introduce the mount structure and their adjustment work. Second part is to give an
introduction of the mount performance test methods and test results finished on NIAOT workshop.
The standard SONG node structure of control system is presented. The active optical control system of the project is a
distributed system, and a host computer and a slave intelligent controller are included. The host control computer collects
the information from wave front sensor and sends commands to the slave computer to realize a closed loop model. For
intelligent controller, a programmable logic controller (PLC) system is used. This system combines with industrial
personal computer (IPC) and PLC to make up a control system with powerful and reliable.
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".<sup>1</sup> 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.
This paper mainly introduces hardware design and control method of the system which is used for detecting
the M<sub>A</sub> segmented mirrors in the LAMOST. According to the demand of sub-aperture stitching interferometer,
the system adopts a control card to control the stepping motor to drive the worktable moving on the X-Y. The
M<sub>A</sub> sub-mirror surface will be changed through active optical correction and add-subtract power of force
actuators. The detection result of the M<sub>A</sub> segmented mirror of 14 shows that root mean square (RMS) of
surface accuracy error is 21.387nm less than 0.035
λ(λ=632.8nm). It is demonstrated that the control system
can work very well and shorten the time of detection.