Filter is a key part for solar chromospheric telescopes. The core of its control system is a high-precision temperature control system. Traditional filter temperature control mode controls the average temperature by switching the heating wire. Such a control mode can not be used for space filters because it consumes a larger power supply. Depending on the space-based solar observatory being studied in China, space filter with automatic wavelength stabilization is being researched and the project intends to work out a method, so as to fit the circumstance in space and to automatically adjust the position through wavelength according to the subtle changes in ambient temperature. Considering the limit for space electronics, this paper describes the design of filter controller based on Field Programmable Gate Array(FPGA) and single chip microcomputer (SCM), which has stronger data processing ability for control algorithm and can be used to receive c1 ontrol commands and upload status. FPGA is used to build multiple communication ports, step motor control Intellectual Property (IP) cores and expand input and output interfaces. The controller can also be used in other telescopes, astronomical instruments and industrial control systems as well.
ASO-S is a mission proposed for the 25th solar maximum by the Chinese solar community. The scientific objectives are to study the relationships among solar magnetic field, solar flares, and coronal mass ejections (CMEs). ASO-S consists of three payloads: Full-disk Magnetograph (FMG), Lyman-alpha Solar Telescope (LST), and Hard X-ray Imager (HXI), to measure solar magnetic field, to observe CMEs and solar flares, respectively. ASO-S is now under the phase-B studies. This paper makes a brief introduction to the mission.
At present, FPGA-based SOPC was used to design the China's LAMOST telescope spectrograph control system. But
with the increase of the controlled objects and requirement of telescope’s accuracy, the problems like system
performance, I/O source shortage, real-time multi-task processing, Fmax, Logic Element (LE) Usage have to be solved
immediately. The combination of multi-processor (NIOS II) method and NOC technology can meet this requirement
effectively. This article mainly introduced how to realize the NOC-based MPSOC in the Altera’s Cyclone III FPGA
experimental board by Qsys tool. According to the function of task, the system was divided into several subsystems
which also include two NIOS II CPU subsystems (implement the control strategies and remote update tasks separately).
These different subsystems are interconnected by NOC hierarchical interconnection idea. The results illustrate that this
solution can improve system performance, double the Fmax, decrease LE usage, and save the maintenance cost
compared with the previous SOPC-based approach. The motor control system designed by this approach also can be
applied to other astronomy equipments and industrial control fields.
One of the Large Sky Area Multi-Object Spectroscopic Telescope (LAMOST) scientific requirements require the ability
of the low resolution spectrograph(LRS) to measure velocities to a accuracy of 4km/s over the entire 5 degree field in 2
hours objects observation. This requirement results in the specification of image movement less than 0.6μm/hours
(0.05pixl/hours corresponding to the science detector).There are 16 spectrographs for LAMOST telescope, so we expect
the design aspects of the instrument directed towards achieving the stability goal. In this paper we present the last design
aspects of the instrument which enable meeting the 4km/s requirement, and the recent test results of the LRS’s Stability
Performance. The test results show that the stability performance of LAMOST-LRS can meet the the stability goal, the
image shift along the direction of dispersion is not influenced by the external factors, and the image shift along vertical
dispersion direction meet the technical requirements when the environmental temperature of the spectrograph room is in
The China-made telescope, LAMOST, consists of 16 Spectrographs to detect stellar spectra via 4000 optical fibers. In
each spectroscope, many movable parts work in phase. Those parts are real-time controlled and managed by field
controllers based on FPGA. The master control board of controllers currently being used is constructed by Altera's
Cyclone II Development Kit. However, now Altera no longer produce such Kits. As the needs for maintenance and
improvement, a backup control board is developed, so that once any field controller is broken, another can changed in
time to ensure the control system not being interrupted. Using the newer Altera FPGA chip 3C40 as master control chip
can minimize the change in the original design frame of the control structure so as to reduce the workload of software
and hardware migration.
This paper describes the design process of the Spectrographs backup field controller based on Cyclone 3C40 and gives
the problems and solutions encountered during migration for controller hardware and software. The improved field
controller not only retains the original controller functions, but also can serve for more motors and sensors due to the
increase of input and output pins. Besides, no commodity supply limits, which saves expenses. The FPGA-field
controller can also be used in other telescopes, astronomical instruments and industrial control systems as well.
Proc. SPIE. 8451, Software and Cyberinfrastructure for Astronomy II
KEYWORDS: Human-machine interfaces, Telescopes, Interfaces, Reliability, Field programmable gate arrays, Control systems, Process control, Software development, Astronomical telescopes, Large telescopes
As the increasing size and more and more functions, modern telescopes have widely used the control architecture, i.e.
central control unit plus field controller. FPGA-based field controller has the advantages of field programmable, which
provide a great convenience for modifying software and hardware of control system. It also gives a good platform for
implementation of the new control scheme. Because of multi-controlled nodes and poor working environment in
scattered locations, reliability and stability of the field controller should be fully concerned.
This paper mainly describes how we use the FPGA-based field controller and Ethernet remote to construct monitoring
system with multi-nodes. When failure appearing, the new FPGA chip does self-recovery first in accordance with prerecovery
strategies. In case of accident, remote reconstruction for the field controller can be done through network
intervention if the chip is not being restored. This paper also introduces the network remote reconstruction solutions of
controller, the system structure and transport protocol as well as the implementation methods. The idea of hardware and
software design is given based on the FPGA. After actual operation on the large telescopes, desired results have been
achieved. The improvement increases system reliability and reduces workload of maintenance, showing good application
This article is focused on the two-level control system of ODL, which are divided into bottom layer control of linear
motor and upper layer control of Piezoelectric Transducer(PZT).This ODL are designed to compensate geometrical
optical path difference, which results from the earth rotation, and other disturbances, with high-accuracy and real time.
Based on the PLC of PMAC controller, the linear motor tracks the trajectory of the simulated optical path difference to
compensate roughly. PZT then compensates the rest error measured by ZLM almost real time. A detailed fulfillment of
this method is shown in the article, and the first result data is produced. The result implies that this method is efficient.
This article offers the reference for the ODL development with the practical high accuracy of compensation.
The China-made telescope, LAMOST, consists of 16 spectroscopes to detect stellar spectra via 4000 optical fibers. In
each spectroscope, many movable parts work in phase. Those parts are real-time controlled and managed by field
controllers based on FPGA. This paper mainly introduces how to use DSP Builder module library in MATLAB /
Simulink to construct the IP control core on FPGA chip. This method can also be used to design the control core of PID
arithmetic, to carry out arithmetic simulation and generate VHDL language file, as well as to integrate it into SOPC
developing environment so as to repeatedly use. In this way, the design period of the control system may be shortened
and design process simplified. Finally due to the reversibility and programmability of the IP control core ,a system on a
chip for field controllers of spectroscope is realized, which meets astronomical control requirements, providing an
effective scheme for embedded system in astronomical instrument applications.
Proc. SPIE. 7740, Software and Cyberinfrastructure for Astronomy
KEYWORDS: Telescopes, Astronomy, Computing systems, Field programmable gate arrays, Control systems, Telecommunications, Astronomical telescopes, Large telescopes, Local area networks, Data communications
Modern telescopes usually have more controlled nodes than classical ones. Those nodes are separately distributed at
various locations of the instrument and not easy to access. While in adjustment, it always requires to modify the control
software, or sometimes to reform the hardware structure and to upgrade the related programs. To solve the problems of
renewing the field controllers, we introduce a FPGA based telescope controller system and a scheme for remoteupgrading
it via Ethernet. This paper mainly describes the structure of the field controller, the requirements for remoteupgrading
and system structure. Also discussed are the protocol applications and extensions, the processing methods as
well as the ideal of software design. The scheme has been in trial run for a large telescope with 16 field controller's subsystem
and excellent results were obtained. It may effectively solve the remote-upgrading problems for multiple field
controllers of large telescopes. Besides the scheme can be used in other multi-nodes industrial control systems too, which
is of high value in applications.
The 16 low resolution spectrographs (LRS) have been successfully commissioned for the LAMOST. The LRS design
employs a dual-beamed and bench-mounted, with large-beamed, fast Schmidt cameras and Volume Phase Holographic
(VPH) transmission gratings. The design wavelength range is 370-900nm, at resolutions of R=1000and R=10000. Each
spectrograph is fed by 250 fibers with 320 micron in diameter (corresponding 3.3 arcsec), composed of one F/4 Schmidt
collimator, a dichroic beam-splitter, four VPH gratings, articulating Schmidt cameras that are optimized at blue band
(370-590 nm) and red band (570-900 nm), and field lens near the focal plane service as the vacuum window of CCD
detector cryogenic head. In this paper, we present the testing result of the LRS on the image quality, spectra resolution,
efficiency and observing spectra.
An optical delay line system for NIAOT Prototype long baseline stellar optical interferometer is being developed. The
delay line system consists of optics part, machine part and control part.
The optics part is a cat's-eye system which includes a paraboloidal mirror and a flat mirror. The flat mirror is placed at
the focus, and is driven by a piezoelectric actuator for real-time compensation of the tracking error. The defocus of the
flat mirror caused by this compensating is considered in optical design; and that the aberration of the optical system
design and the manufacture precision of optical components should not cause the decline in visibility of the fringe is
The machinel part includes precision rails and delay line carriage. The rails require high stability and parallelism. The
cart should be quakeproof when it is moved continuously in the observation process, so the rolling friction drive mode is
selected as the suitable link method between the carriage and the rails.
The control part includes delay line carriage device control and laser metrology system device control. During an
observation, an astrometric model provides a demand cart position and velocity to control computer, the control
computer send them to the device controllers. The metrology system produces tracking error fed back to the cart device
controller via the control system. This feedback servo loop controls the tracking error.
A large Schmitt reflector telescope, Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST), is being
built in China, which has effective aperture of 4 meters and can observe the spectra of as many as 4000 objects
simultaneously. To fit such a large amount of observational objects, the dispersion part is composed of a set of 16
multipurpose fiber-fed double-beam Schmidt spectrographs, of which each has about ten of moveable components realtimely
accommodated and manipulated by a controller. An industrial Ethernet network connects those 16 spectrograph
controllers. The light from stars is fed to the entrance slits of the spectrographs with optical fibers.
In this paper, we mainly introduce the design and realization of our real-time controller for the spectrograph, our design
using the technique of System On Programmable Chip (SOPC) based on Field Programmable Gate Array (FPGA) and
then realizing the control of the spectrographs through NIOSII Soft Core Embedded Processor. We seal the stepper
motor controller as intellectual property (IP) cores and reuse it, greatly simplifying the design process and then
shortening the development time. Under the embedded operating system μC/OS-II, a multi-tasks control program
has been well written to realize the real-time control of the moveable parts of the spectrographs. At present, a number of
such controllers have been applied in the spectrograph of LAMOST.
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) project is one of the National Major
Scientific Projects undertaken by the Chinese Academy of Science. There are 16 low resolution multipurpose fiber-fed
spectrographs in total, enabling it to obtain the spectrum of celestial objects as faint as down to 20.5. Building auto-focusing
systems for the spectrographs is important due to the popularity of instruments. The system enables the optical
system to automatically compensate changes in accordance to external variables, such as temperature, timidity, to ensure
the spectrum collected more reliably. Image-based algorithm is utilized to calculate the departure of CCD plane from
optical focal plane. The calculation also aids to regulation of the system. The defocus value is transformed to the
controlling computer of each spectrograph. A driving step-motor performs refocusing function by moving the fiber slit
unit to its right position.
A multipurpose fiber-fed double-beam Schmidt spectrograph using VPHG (volume phase holographic gratings) is under construction for LAMOST (The Large Sky Area Multi-Object Fiber Spectroscopic Telescope). There are 16 such spectrographs (hereafter referred to as LRSs) for the project. The spectrographs are designed with wavelength coverage from 370 to 900 nm, with spectral resolutions of 1000-10000, and with multi-object capability over a 5 degrees field of view. Each spectrograph will be accommodating 250 fibers of 320 microns diameter (corresponding 3.3 arcsecs). The 200 mm diameter collimated beam is split into two separate channels. The blue channel is optimized for 370nm-590nm, and the red channel for 570nm-900nm. The LRS can work in several varied resolution modes. The optical design and performance is described. The spectrograph is of simple design with moderate image quality and good throughput. Progress on the construction of LRS is reported as well.
High precision magnetic analyzer is one of key points in technologies of Chinese space solar telescope, which is under pre-investigation. Magnetic analyzer needs a modulation component to change its polarization state. For ground-based use, usually electroptics crystal KD*P is a good option. However KD*P needs a power supply as high as thousands volts. In space environment, such a high pressure source is hardly available. Therefore we have to use an alternative, an optomechical modulator. In the modulator, the related optical components rotate precisely to realize modulation. This raises a crucial request for position accuracy and positioning times of optical components rotation. This paper describes our developing process of the electric control for the magnetic analyzer. Firstly, hardware facilities, control software design and test results as well are given. Then, some problems in manufacture and adjustment are analyzed and discussed. After overall optical, mechanical and electric tests, it shows that the accuracy of rotation position of the optical components is better than 10"(p-p) (checking with a precise 24 sides' standard); while time for rotating 90 degrees is less than 2 seconds. The results demonstrate that the magnetic analyzer has met the design requirements.
This paper introduces our control software design for a tracing system of precise pointing on a balloon-borne telescope to observe the active details on the solar surface. The telescope is an equatorial one with 80 cm in diameter. Borne by balloon, it works at 30 km above the sea level so as to get rid of the image disturbance due to atmosphere. The system contains three parts: basket control, telescope control and tip-tilt control. For telescope control, the crude sensors for pointing detection are two rotating transformers, while the fine sensors two linear CCDs which produce the error signals of pointing. An inserted-type industry-control computer PC104 completes the position close-loop and then drives the servo amplifiers to carry out pointing, searching and tracing automatically. Due to the fact that the position control loop is closed with an improved digital PID arithmetic, the adjustment of the telescope may respond rapidly, therefore the telescope can precisely follow the Sun on the balloon. Simulation test shows that the tracing accuracy may reach as high as 4" (RMS).