Development Status of Angular Detector with High Accuracy
Development Status of
Angular Detector with
High Accuracy
Yutaka Karasawa
(TAMAGAWA SEIKI CO,. LTD.)
Hiroshi Miyaba ，Shingo Obara ，Mineo Suzuki
(Japan Aerospace Exploration Agency)
October 28 , 2005
TAMAGAWA SEIKI CO,. LTD.
TAMAGAWA SEIKI CO., LTD.
-1-
2005/10/28
Development Status of Angular Detector with High Accuracy
C o n t e n t s
1. Background
2. Features
3. Outline
(1) Specification & outer shape
(2) Block diagram
(3) Structure
4. Principle of resolver
5．Key elementｓ
(1) 1X-32X multi-speed resolver
(2) Ball bearings
(3) RD converter circuit
6. Development schedule
7. Information
TAMAGAWA SEIKI CO., LTD.
-2-
2005/10/28
Development Status of Angular Detector with High Accuracy
１． Background
Satellite
manufacturer
Overseas
procurement of
angular detector
Single source of
optical encoder
Instability of supply ------ Exclusive supply from single
overseas manufacturer
Delay of satellite development plan
Large cost for development, manufacturing and operation
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
２．Features
Object
: To secure flexibility and reliability of key
space components by domestic
envelopment.
Applications : ・Antenna & Optical sensor pointing
mechanism
Features
: ・High accuracy and resolution
・Compact and light weight
・I/F compatibility with existing optical
encoder
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
３．Outline
(1)Specification & Outer shape
Item
Specification
Imports Optical encoder
Sensing method
Resolver＋RD converter
（electromagnetic induction）
Optical
Angular accuracy
＜ ±0.0015°
（ ＜ ±5 ″）
＜ ±0.0015°
（ ＜ ±5 ″）
Resolution
21 bit
18 bit
Mass
＜ 2.0 kg
＜ 2.2 kg
Power
＜ 2.0 W
＜5W
Input/Output
Differential type
(EIA RS422)
Differential type
(EIA RS422)
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
(2)Block Diagram
The angle is detected by resolver section and transmitted in analog signal.
This analog signal is converted to digital signal by RD converter to transmit..
Rotary transformer
Stator
Rotor
Rotor
RD converter
Resolver
Stator
Line
Driver
Line
Receiver
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
(3)Structure
Special features
¾Titanium alloy is adopted for minimizing
the weight.
¾High-permeability magnetic material is
adopted for resolver section
¾The resolver section is structured as
pan-cake type for small size and light
weight and located concentrically to the
bearing.
¾High precision thin-section ball bearings
are adopted for small size.
¾High density on surface components are
adopted for small size.
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
4 ． Principle of Resolver(1/2)
‹Resolver consists of one rotor and one stator , the rotor can be freely rotated.
‹Non-contact type rotary transformer is used instead of the conventional brushes and
slip rings to transfer the signal (i.e. exciting voltage) to the rotor of resolver.
‹When the exciting winding is excited by AC voltage (i.e. AC 10～ 60 V, 60 Hz～ 10
kHz), a couple of voltages with SIN and COS function of the rotor angle) is generated
by the electromagnetic induction effect on the output winding.
‹The angle of rotor can be measured by reading out the two output voltages, because
the output voltages are varied corresponding to the rotational angle of resolver rotor.
Output voltage
Rotor & rotary
transformer
COS S1-S3
SIN S2-S4
90°
Stator & rotary
transformer
TAMAGAWA SEIKI CO., LTD.
180°
270°
360°
Resolver output
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2005/10/28
Development Status of Angular Detector with High Accuracy
4 ． Principle of Resolver(2/2)
‹Multi-speed resolver has the electric shaft angle multiplication of 32 times (i.e. number of pole
is 64 poles) and the output signals have 32 cycles per one revolution of mechanical shaft.
‹When two kinds of resolvers (i.e. single and multi-speed resolvers) are located on the same
single iron core to obtain both signals of 1X and 32X, the absolute signal around one revolution
of mechanical shaft can be detected.
‹The angle detection accuracy is decided by the SIN and COS output voltages of 32X resolver.
The angle detection accuracy of 32X resolver for one cycle (i.e. electrical angle of 360
degrees) of its output signal is approximately the same level of 1X resolver, but this angle
detection accuracy is deducted to 1/32 in the view from the mechanical angle of 360 degrees.
Output voltage
Output voltage
Electrical angle 360°
Mechanical angle 360°
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
５． Key Element ｓ
（1）1X-32X Multi-speed Resolver
Angle detection is carried out.
Magnetic material
☆ High accuracy
Coil
☆ Pancake type
☆ Redundant winding
☆ Space materials
Resolver stator
TAMAGAWA SEIKI CO., LTD.
Resolver rotor
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2005/10/28
Development Status of Angular Detector with High Accuracy
Rotary Transformer
Exciting voltage is transferred to the rotor.
☆ High efficiency.
Magnetic material
Plastic
☆ Pancake type
☆ Redundant winding
☆ Space materials
Rotary transformer stator
TAMAGAWA SEIKI CO., LTD.
Coil
Rotary transformer rotor
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2005/10/28
Development Status of Angular Detector with High Accuracy
Trial Results(1/2)
1X-32X Multi-speed Resolver＋ Rotary Transformer
Test
procedure
Specifications
Power
< 0.35 W
1X
Output
voltage
32X
1.25Vrms
±10％
1.25Vrms
±10％
Results
Main
Redundant
0.240W
0.247W
pass
S1-S3
1.328V
1.324V
pass
S2-S4
1.326V
1.326V
pass
S5-S7
1.281V
1.284V
pass
S6-S8
1.279V
1.286V
pass
1X
< ±20°
+9.35°
+9.35°
pass
32X
< ±20°
+9.35°
+9.35°
pass
< ±60 ′ (1X-32X)
+31.2′
+29.4′
pass
< ±30 ′
(Main- redundant)
---
+1.5′
pass
Phase shift
Zero point
shift
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
Trial Results (2/2)
X-32X Multi-speed Resolver＋ Rotary Transformer
Accuracy
10
8
Accuracy (arcsec)
6
±0.001°
4
2
0
-2
-4
-6
-8
-10
0
30
60
90
120
TAMAGAWA SEIKI CO., LTD.
150
180 210
Angle (deg)
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240
270
300
330
360
2005/10/28
Development Status of Angular Detector with High Accuracy
(2) Ball Bearings
☆ High precision thin-section ball bearings
☆ Angular contact
☆ Type DB （Back to Back)
☆ Space grease lubrication
☆ Low torque
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
Ball Bearings Flow
Acceptance test
Preserved in oil
Lubrication
Running torque test (single)
Assembly & preloading
Preload test
Running torque test (pare)
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
Trial Results
軸受7Torque
80 9摩擦トルク温度試験結果
Running
of Ball Bearings
200
-30℃
-20℃
0℃
+25℃
+50℃
+70℃
+80℃
180
160
(Nmm)
摩 擦Torque
トルク　(N
・m m ）
140
120
100
80
< 180 Nmm
60
40
20
0
0
10
TAMAGAWA SEIKI CO., LTD.
Speed (r/m)
回転数　（rpm）
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20
30
2005/10/28
Development Status of Angular Detector with High Accuracy
（３） RD Converter Circuit
Analog angle signal from resolver is converted to digital signal.
☆ High accuracy ＆ resolution
☆ Compact
☆ Low power
☆ Space electrical parts
TAMAGAWA SEIKI CO., LTD.
-17-
2005/10/28
Development Status of Angular Detector with High Accuracy
Trial Results
RD Converter Circuit
Test procedure
Specifications
Power
< 2.0 W
1.28 W
pass
Accuracy
＜ 0.0005°
0.0003°
pass
Results
Resolution
21 bit
21 bit
pass
Output voltage
7Vrms±3% 2192Hz±5%
7.139Vrms 2283Hz
pass
Tracking rate
> 30 r/m
31.0 r/m
pass
OK
pass
Input/Output I/F
＞ 2μs :3.2μs
Updated command 1
＜Input＞
0
1
Updated complete
0
＜Output＞
Clock
＜Input＞
1
Data
＜Output＞
1
＜ 300kHz DUTY=50%±10% :308.6kHz 50.0%
＞500ns
0
20
MSB
19
18
02
01
0
LSB
0
＜2μs: 640ns
＜100ns: 20ns
0.4～4μs：0.50～3.43μs
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
6. Development Schedule
Japanese Fiscal Year
2003
2004
2005
2006
Preliminary design
PDR
Detailed design
CDR1 CDR2
Sustainable design
PQR
BBM
QM
TAMAGAWA SEIKI CO., LTD.
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2005/10/28
Development Status of Angular Detector with High Accuracy
7.Information
TAMAGAWA SEIKI Co., Ltd.
1879 OHYASUMI , IIDA , NAGANO PREF, 395-8515 JAPAN
TEL:0265-21-1800 FAX:0265-21-1881
TAMAGAWA SEIKI
Headquarters
South Alps mountains range
Tenryu river
Iida city
TAMAGAWA SEIKI CO., LTD.
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2005/10/28