Opto-mechanical Structure Design and Intelligent Error Allocation of K-mirror Derotator

Xinqiqige; Yi CHEN; Hangxin JI; Lei WANG; Yongtian ZHU; Kai ZHANG; Huatao ZHANG

doi:10.3788/gzxb20225103.0322002

Journals >Acta Photonica Sinica >Volume 51 >Issue 3 >Page 0322002 > Article

Acta Photonica Sinica
Vol. 51, Issue 3, 0322002 (2022)

Opto-mechanical Structure Design and Intelligent Error Allocation of K-mirror Derotator

Xinqiqige^1、2、3, Yi CHEN^1、2、*, Hangxin JI^1、2, Lei WANG^1、2, Yongtian ZHU^1、2, Kai ZHANG^1、2, and Huatao ZHANG^1、2

Author Affiliations

¹National Astronomical Observatories/Nanjing Institute of Astronomical Optics & Technology，Chinese Academy of Sciences，Nanjing 210042，China

²CAS Key Laboratory of Astronomical Optics & Technology，Nanjing Institute of Astronomical Optics & Technology，Nanjing 210042，China

³University of Chinese Academy of Sciences，Beijing 100049，China

show less

DOI: 10.3788/gzxb20225103.0322002 Cite this Article

Xinqiqige, Yi CHEN, Hangxin JI, Lei WANG, Yongtian ZHU, Kai ZHANG, Huatao ZHANG. Opto-mechanical Structure Design and Intelligent Error Allocation of K-mirror Derotator[J]. Acta Photonica Sinica, 2022, 51(3): 0322002 Copy Citation Text

show less

Fig. 1. Opto-mechanical schematic diagram of derotator（K-mirror）

Download full size | View in the Article

Fig. 2. Opto-mechanical structure design of K-mirror

Download full size | View in the Article

Fig. 3. Optimize iterative convergence graph

Download full size | View in the Article

Fig. 4. Fitting graphs of KM1，KM2，and KM3 pose cycle changes obtained by finite element analysis

Download full size | View in the Article

Fig. 5. Focal plane graphics from error simulation analysis

Download full size | View in the Article

Fig. 6. Experimental bench of K-mirror

Download full size | View in the Article

Fig. 7. Graphics on CCD

Download full size | View in the Article

Item	Error sources
System error	Main mirror processing error （KM1，KM3 pose error）
	Elastic deformation error
	Machining error and installation error of endoscope tube
	Machining error and installation error of outer tube
	Bearing selection and installation error	Outer ring error
	Bearing selection and installation error	Inner ring error
Random error	Bearing runout error

Table 1. Error sources of K-mirror derotator

View in the Article

Main error source		Sub-error source	Error distribution
Elastic deformation error	KM1 pose error	Tz /mm	0.044 7
		Rx /rad	0.000 137
		Ry/mm	0.000 225
	KM2 pose error	Tz /mm	0.079 1
		Rx /rad	0.000 05
		Ry/rad	0.000 4
	KM3 pose error	Tz /mm	0.049 0
		Rx /rad	0.000 167
		Ry/rad	0.000 05
Main mirror processing error		θ1/（）	0.008 42
		θ2/（）	0.010 3
		θ3/（）	0.005
Bearing bus inclination error		E1/mm	0.005
Bearing coaxiality error		（X1+X2）/2/mm	0.005
		（Y1+Y2）/2/mm	0.009 32
		（X1-X2）/2/rad	0.000 5
		（Y1-Y2）/2/rad	0.003 91
Lens barrel error	Inner tube error	IRx/（）	0.029 5
	Inner tube error	IRy/（）	0.022 09
	Outer tube error	ORx/（）	0.013 08
	Outer tube error	ORy/（）	0.006 54
Qualified rate of focal plane graphics/%			96
Derotation pointing accuracy			0.18 mm（）

Table 2. Optimization results of key component error distribution

View in the Article

Key components	Selection and tolerance level	Tolerance range
Key components	Selection and tolerance level	Tolerance position		Tolerance
Bearing	Bearing type ：FAG 71934C Precision level：P4	Average inner diameter variation		0.005 mm
		Average outer diameter variation		0.006 mm
		Width variation		0.005 mm
		Radial runout of inner ring of complete bearing		0.006 mm
		Radial runout of outer ring of complete bearing		0.01 mm
		Bearing bus inclination error		0.007 mm
Inner tube	Central axis perpendicularity tolerance level：8	Size：544 mm		$3.2 μ m$
Inner tube	Coaxiality tolerance level of bearing mating shaft section：6	$70 μ m$
Outer tube	Central axis perpendicularity tolerance level：7	Size：230 mm		$1.6 μ m$
	Tolerance class of perpendicularity Installation interface：6	Diameter：660 mm		$80 μ m$
	Coaxiality tolerance level of bearing mating shaft section：6	$80 μ m$
Elastic deformation	Structure optimization of inner and outer tube and main mirror	Maximum deformation of structure		0.008 8 mm
Main mirror	Inclination tolerance level：5	Surface size	Length：260 mm	$0.007 05 °$
Main mirror	Inclination tolerance level：5	Surface size	Width：160 mm	$0.008 95 °$

Table 3. Selection of tolerance grades of key components and bearing models

View in the Article

Materials	Density/ （g·cm^-3）	Young`s modulus/ $(\times 10^{10} P a)$	Poisson ratio	CTE/ $(\times 10^{- 6} ℃)$	Specific heat capacity/ （J $∙$ $k g^{- 1} ∙ K^{- 1})$	Thermal conductivity/ （W $∙$ $m^{- 1} ∙ K^{- 1})$
Zerodur	2.53	9.06	0.24	$0 \pm 0.05$	821	1.64
Invar	8.05	14.1	0.259	1.26	——	10.4
40Cr	7.9	20~21.17	0.25~0.3	11	460	66.6
65Mn	7.82	19.7	0.282	11.1	——	——
Polytef	2.10~2.30	20.8 （Compression） 70 （Bending）	0.4	1.03~1.28	——	0.256

Table 4. Material parameters of K-mirror

Download Citation

Save the article for my favorites

Paper Information