Conceptual Design for Control System of Segmented Primary Mirror in SEIMEI Telescope

SICE Journal of Control, Measurement, and System Integration

et al. 2021

Self Cite

A segmented mirror control system is indispensable for operating an astronomical telescope which is equipped with a segmented primary mirror. In this study, we focus on the distributed control system (DCS) proposed for Seimei telescope. An interesting hierarchical structure is found by analysing its zero-nonzero structure in the DCS, and then, 54 gains are reasonably classified into 4 groups. Design examples for selecting gains of the DCS are presented so that the closed loop pole locations are similar to those of the centralized control system (CCS). The freedom in the selections of gains by taking account of the hierarchical structure is shown to be effective by numerically evaluating the stability region and by optimizing the maximum distance between the closed loop poles of DCS and CCS.

“…where t ∈ R is the continuous time, x ∈ R 54 is the state, u ∈ R 54 is the input, y ∈ R 72 is the output, and C ∈ R 72×54 is the constant matrix called the action matrix [5].…”

Section: Preliminariesmentioning

confidence: 99%

“…The authors have proposed two types of segmented mirror control algorithms for Seimei telescope [5]. One algorithm is called the Centralized Control System (CCS) and the other is called the Distributed Control System (DCS), and they are expected to play complementary roles.…”

Section: Introductionmentioning

confidence: 99%

Structure of distributed control system in Seimei telescope

Jikuya

Uchida

SICE Journal of Control, Measurement, and System Integration

et al. 2021

Self Cite

“…where t ∈ R is the continuous time, x ∈ R n is the state, u ∈ R n is the input, y ∈ R p×n is the output, and C ∈ R p×n is the constant matrix called the action matrix. For example, the control system of the segmented main mirrors is modeled by the MIMO integrator model in the SEIMEI telescope, where the dimensions are n = 54 and p = 72 [3]- [5]. The nominal value of C is determined from the design parameters of the SEIMEI telescope.…”

Section: Preliminaries and Problem Formulationmentioning

confidence: 99%

“…The nominal value of C is determined from the design parameters of the SEIMEI telescope. Two types of constant output feedback control algorithms have been presented and tested in simulations for the nominal value of C by the authors [3]- [5].…”

Section: Preliminaries and Problem Formulationmentioning

confidence: 99%

“…In this paper, we consider open-loop system identification of the multi-input multi-output (MIMO) integrator model which is a multiplication of a constant matrix and the integrator. This work is inspired by the control system of the segmented mirrors in the SEIMEI telescope [3]- [5]. Compared with the previous studies [1], [2], our problem is simpler in one aspect because the asymptotically stable dynamics is not included in the system model, whereas our problem is more difficult in the other aspect because the MIMO system is considered.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Open-Loop System Identification of MIMO Integrator Model

Jikuya

SICE Journal of Control, Measurement, and System Integration

Yamada

2020

Self Cite

This paper considers the open-loop system identification of a multi-input multi-output (MIMO) integrator model which is a multiplication of a constant matrix, called the action matrix, and the integrator. Our problem is to estimate the action matrix from the measured input and output data. The estimation algorithm is proposed by removing trends from the numerically integrated input and output so that the effects of input and output disturbances are eliminated. The proposed method is applicable to the basic scenario (constant input and output offsets), which is similar to previous studies, and the non-constant output offset; however, it is not applicable to the non-constant input offset. The discussion in this paper indicates the essential difficulties in the open-loop system identification with the integrator.

The Seimei telescope project and technical developments

Kurita

Publications of the Astronomical Society of Japan

Iwamuro

et al. 2020

An overview of the Seimei telescope, a 3.8 m optical infrared telescope located on Mt. Chikurinji in the Okayama prefecture of Japan, is presented. Seimei is a segmented-mirror telescope whose primary mirror consists of 18 petal-shaped segments. The telescope tube supporting the thin segmented mirrors is structurally incorporated within large arc-rails providing the elevation axis. The tube has a light-weight homologous structure designed with a genetic algorithm. The total weight of the telescope tube, including 1.4-ton optics, is only 8 tons. By virtue of its light weight, the telescope is able to point at an object anywhere in the observable sky within one minute. The telescope is operated by Kyoto University in collaboration with the National Astronomical Observatory of Japan (NAOJ). Half of the telescope time is used by Kyoto University. The remaining time is open to the Japanese astronomical community. NAOJ is responsible for the management of the open-use time, including handling of the observation proposals. The telescope is now regularly performing scientific observations on the basis of a variety of proposals.