JPH03127015A - Submirror oscillating device - Google Patents

Abstract

PURPOSE:To realize high positioning accuracy, a short transition time, and a large amplitude by generating the attractive force and the resiliency between a 1st, a 2nd reflecting mirror driving coils and a 1st, a 2nd compensating plate driving coils respectively and driving a reflecting mirror and a compensating plate to be oscillated with the couple of the forces. CONSTITUTION:The 1st and 2nd reflecting mirror driving coils 105a and 105b are connected in series or in parallel and the same currents flow in opposite directions. The 1st and 2nd compensating plate coils 106a and 106b are the same and the currents of the coils 105a and 106a, and coils 105b and 106b flow in opposite directions. Consequently, the attractive and repulsive forces are generated between the coils and the reflecting mirror 101 and compensating plate 102 are oscillated with the couple of the forces. Further, position detection sensors 108 and 109 detect the oscillating angles of the reflecting mirror 101 and compensating plate 102 and feed them back to perform control so that the deviation from an object signal becomes zero. Consequently, the positioning accuracy is improved and the short transition time and large amplitude are obtained.

Description

Detailed Description of the Invention [Industrial Field of Application] This invention is a telescope, particularly an infrared telescope, in which the influence of background noise from the earth's atmosphere is removed by the spatial chipping method. This invention relates to a secondary mirror swinging device that swings a mirror in a rectangular wave shape at high speed and with high precision. (The spatial telebing method is a method of removing observation noise by alternately observing light from a celestial body that includes background noise and only background noise, and finding the difference between them. ) In particular, the secondary mirror rocking device used in this invention is used in high-resolution telescopes that can observe celestial bodies more than 15 billion light years away.
Therefore, compared to conventional mirrors, the diameter of the secondary mirror is larger, the swing accuracy is higher, the transition time is shorter, and the diameter of the 7'I is larger.
tlij width is required.

[Prior Art] Fig. 7, Fig. 8, Fig. 9, and Fig. 1O are sectional views showing a conventional secondary mirror swinging device and a secondary mirror swinging device disclosed in Japanese Patent Application Laid-Open No. 58-189607, respectively. FIG. 2 is an enlarged view of the return adjustment spring device incorporated in the actuator, a drive circuit diagram of the actuator, and a diagram showing the force balance between the actuator and the r14″M spring device. In these figures, <26> is the secondary mirror. , (28> is the compensation plate, (20> is the iron core of the actuator that drives the secondary mirror (26>) and the compensation plate 1-(28), (14>, (16) is the coil of actuator a2, (
30> has a beggar J on the secondary mirror <26> and the compensation plate <28>
Keketa retainer, (34〉,〈36〉 are the secondary mirrors (2
6) and the swing axis of the compensation plate (28>, (50>, (5
2〉 is the secondary mirror〈26〉 and compensation play 1-(28〉) respectively.
Spring to keep at zero position, (all), (s21)
is a changeover switch for driving the actuator in a rectangular waveform, and (64) and (6B> are power supplies for driving the actuator. In Fig. 9, the horizontal axis represents the iron core (20) of the actuator and the retainer. The air gap between (30) or the amount of deformation of springs (50) and (52), the vertical axis is the attractive force or spring (50) that acts between the iron core (20> and the retainer (30)).

(52〉 represents the force generated, and the curve a1 is the coil (14
Curve Q2 shows the relationship between the above-mentioned attractive force generated when a small current is passed through the coil (14) and the air gap.
The curve a3 shows the relationship between the force generated by the springs (50) and (52) and the amount of deformation, respectively. Also, the intersection Q
4 is the point where the above-mentioned attractive force and the force generated by the spring balance each other.

Next, the operation will be explained. In this device, by passing current through the coil (14) shown in FIG.
Attractive force acts between the iron core (20> on the side of 14) and the retainer <30>, causing the secondary mirror (26> and compensation plate (28) to rotate around the swing axes <34) and (36>, respectively). Rotate clockwise and counterclockwise.At this time, the springs (50>, <52>) on the side of the coil (14) are compressed, and the coil <16> is compressed.
The springs (50〉, (52〉) on the side of
attempts to return to the zero position. The secondary mirror (26) and the compensating plate (28) each rotate to a position where the attractive force of the actuator and the return force are balanced, as shown in FIG. 1O, and then stop. Next, when the switch (sll) in Fig. 9 is turned off and the switch (s21) is turned on, the first current flowing through the coil (14> is cut off and the current flows through the coil (16>), and the current flows through the coil (16>).
There is an attractive force between the iron core <20> and the retainer (30>) on the 6> side, and the secondary mirror (26> and compensation plate (28) rotate in the opposite direction this time, and the fishing It stops at the matching position.By sequentially switching the switches (s11) and (s21), the above operation is repeated and the secondary mirror (26) and the compensation plate (28> swing in a rectangular wave shape.In this device, The period of the oscillation can be changed by switching and changing the switching period, but the transition time from one stop position to the other stop position is determined by the secondary mirror (26) and the spring (52) (
It depends on the natural vibration period determined by the compensation plate (28) and the spring (50).

[Problems to be Solved by the Invention] As described above, the conventional secondary mirror rocking device has the If! tFa, there were the following problems.

First, when trying to shorten the transition time, the spring (50)
, (52> needs to be made hard, but in this case,
As can be seen from Figure 1O, even if the driving force is increased, it is difficult to obtain as large an amplitude as was originally obtained, and furthermore, in order to obtain critical damping, it is necessary to use a braking device using eddy currents. It is necessary to improve the damping performance of the secondary mirror (26〉) and compensation plate 1-(28) in the stopped position against the stiff spring. There is a problem in that a large current must be passed through the actuator.In addition, the above device has a structure in which the driving force of the drive motor acts only on one retainer (<30), so it is necessary to apply a large current to the actuator. Then, the spring (50
), <52) and the retainer (30>), the bending force acting on the secondary mirror (26) increases, and furthermore, the bending force acting on the oscillating shaft (34), (
There is also the problem that a large force is applied to 35) and the positioning accuracy is sufficiently compromised.

Second, the force that drives the secondary mirror is the iron core <20> and the retainer (3
Since it is determined by the difference between the attractive force of 0〉 and the spring force generated by springs (50〉 and (52〉), for example,
It is not possible to drive with the optimum driving force waveform as shown in FIG.
In addition to this problem, there is a fatal problem in that the transition time cannot be shortened beyond a certain level.

Thirdly, as can be seen from Figure 10, the attractive force between the iron core (20〉) and the retainer (30〉)
) is inversely proportional to the square of the air gap (swinging angle of the secondary mirror), so if the above-mentioned attractive force is increased in an attempt to increase the amplitude, the intersection with the return force by springs (50) and (52) will be There is an inherent problem in that it is impossible to keep the secondary mirror at a certain fIL (large amplitude), which is difficult to achieve, and this is a major constraint in the design of the above device.

Finally, the stopping position of the secondary mirror is set between the iron core (20) and the retainer (3).
Since it is determined only by the balance between the attractive force between 0> and the return adjustment force caused by the springs (50) and (52>), there is a problem that it is difficult to improve the swing accuracy beyond a certain level.

This invention was created to solve the above-mentioned problems, and an object of the present invention is to provide a secondary mirror swinging device that can realize high positioning accuracy, short transition time, and large amplitude.

[Means for Solving the Problems] A secondary mirror rocking device according to the present invention includes a secondary mirror button, a compensation plate, and the above-mentioned secondary mirror, which are arranged opposite to each other and are swingable about rocking shafts each supported by a fixed part. The first and second secondary mirror drive coils are respectively attached to the secondary mirrors on both sides of the swing axis between the mirror and the compensation plate, and the coils are respectively attached to the compensation plates on both sides of the wind axis between the secondary mirror and the compensation plate. 1st, 2nd
a first compensation plate drive coil, which is fixedly disposed between the secondary mirror and the compensation plate, generates attraction and repulsion forces with each of the coils, and swings the secondary mirror and the compensation plate by a couple; A second secondary mirror drive magnetic circuit, a first and second compensation plate drive magnetic circuit, and a sensor for detecting the respective swing angles of the secondary mirror and the compensation plate, and a signal from the sensor is applied to each of the coils. This configuration is configured to perform feedback control on the current flowing through the sensor.

Further, a secondary mirror rocking device according to another aspect of the present invention includes a secondary mirror and a compensating plate that are arranged opposite to each other and are movable about rocking shafts supported by respective fixing parts. The first and second secondary mirror drive coils are respectively attached to the secondary mirrors on both sides of the swing axis between them, and the secondary mirror drive coils are attached to the compensation plates on both sides of the swing axis between the secondary mirror and the compensation plate. First and second secondary mirror drive magnetic circuits that generate attraction and repulsion forces with the coils to swing the secondary mirror by a couple; The first and second compensation plate drive coils are fixedly arranged opposite to each compensation plate drive coil, and the attraction and the second compensation plate drive coils are respectively attached to the compensation plate drive coils.
The sensor comprises first and second compensation plate driving magnetic circuits that generate a repulsive force and swing the compensation coil by a couple, and a sensor that detects the swing angle of each of the secondary mirror and the compensation plate. The current applied to each coil is feedback-controlled based on the signal.

[Operations] The secondary mirror rocking device according to the present invention detects the positions of the secondary mirror and the compensation plate and performs positioning (closed loop control), so high positioning accuracy can be achieved. In addition, since the secondary mirror and the compensation plate are driven by a couple, no moment is generated on the rotating shaft and the support part due to the reaction force of the driving force, improving positioning accuracy, and shortening the transition time.
Large amplitude can be achieved.

[Example 1] An example of the present invention will be described below with reference to the drawings. 1st
FIG. 2 is a partial cross-sectional view of a swinging device t according to an embodiment of the first invention, FIG. 2 is a side sectional view thereof, and FIG. 3 is a block diagram of its control system.

In these figures, (101) and (102) are the secondary mirror and compensation plate arranged oppositely, (103) and (
104) C each secondary mirror (101> and compensation play 1-
A swing shaft that swingably supports (1G2), (105Q
), (105b) are the coils of the linear motors for driving the first and second secondary mirrors, (108a), (106
b) are both 1B+1 (+) of the swinging wheel (104).
Compensation P L, -1-(102) 1. :, Coil of the linear motor for driving the first and second compensation plates,
(107a), <107b) is the first. Magnetic circuit of the linear motor for driving the second secondary mirror, (lla), (llll
b) is a magnetic circuit of a linear motor for driving the first and second compensation plates (108);

(109)<1 each secondary mirror (101) t! - High-precision sensor that detects the swing angle (displacement) of the compensation plate (102>, (110) is the swing axis (103), <104>
, magnetic circuit (107Q).

<107b) and a base with sensors (108) and <109) attached, (112) is a magnetic circuit (107a),
(107b), (111a), and (111b) are supported between the secondary mirror (101) and the compensation plate 〒1-(102〉). Transfer function from the swing angle of the secondary mirror (101), (122) Transfer function from the driving force of the beam near motor to the swing angle of compensation play 1-(102), (1
31) is the magnetic circuit (IQta), (107b), (
The magnetic circuit (10
7Q), (107b) (lla), (lllb)
The transfer function to the oscillation angle is 〈127n, (128) is the transfer function of the stabilizing compensator, (129) and (130) are the oscillation angle (displacement) of the secondary mirror (101) and the compensation plate (102), respectively. ) is the gain of a high-precision sensor that detects

In addition, ('l), ('2> are the target signals of the secondary mirror (101) and compensation play 1-(102), respectively, (θl>, (θ
2) are a secondary mirror (101) and a compensation plate (102), respectively.
), (θ3〉) is the magnetic circuit (107a), (1
07b), (111(1), (lllb>).

Next, the operation will be explained. In the apparatus shown in FIGS. 1 to 3, the first and second secondary mirror drive coils (105n), (1
05b) are connected in series or in parallel and twisted so that the same current flows in opposite directions.

First and second compensation plate drive coils (106a), <
The same applies to 106b), and furthermore, if the coil < 10
5o) and (108a) and (105b) and (108b)
) The chisel flow force is configured to be reversed. Also, during normal driving, the target trajectory <"l", ("2
〉 is also the same as 17. Therefore, 4 pieces (1> :x (
le (105o), (105b), (106o),
(106b) (=The magnitude of the acting force is the same. In this way, the force is the same as that of the secondary mirror (101) and the compensation play 1-(102
), the secondary mirror (101) and the compensation plate 1- (102) are rotated around the swing axis (103), <104) by a couple force, respectively. Target signal (
"l), ("2> is a signal so that the optimum driving force waveform as shown in Fig. 11 is recorded, and the position detection sensor (108)
, (109) detect the swing angles of the secondary mirror (101) and compensation play 1-(102), respectively, and the control system feeds this back to detect the deviation from the target signals ('l〉, (r2〉). In order to control the angle to zero, the secondary mirror (101) and the compensation play 1-(102) can be driven with high accuracy (approximately 0.1%) to the target signals ('l>, ('2>). In addition to high-precision driving, this device has two functions:
It is possible to achieve excellent effects. .

l) Magnetic circuit (107a), (1G7b), (11
1 (1), since the resultant force of the reaction force acting on (lllb> is zero, the base (110) and the support (112)
There is a lot of force acting on it.

2) Since the secondary mirror (101) swings due to a couple, the "bending force of the secondary mirror due to the coil and return spring" that occurs in the conventional example is unlikely to occur.

3) Since the secondary mirror (101> and the compensation plate (102) swing zero due to the couple, a reaction force acts on the swing shafts (103) and (104).A torsion spring is attached to the swing shaft. When used, the moment proportional to the spring constant and the swing angle is the base (1
10), but the secondary mirror (101) and the compensation plate L, -
1-(102) (D IIIEII Since the angle is actively controlled by the control system, the spring constant of the torsion spring can be made extremely small, and the base (110) <:
6% transmission can be reduced to almost zero.

As mentioned above, with this device, the drive speed is increased and the secondary speed is increased. (10
1) and by increasing the driving amplitude, it has the essential feature that even if the driving force is increased, the force acting on the base (110) can be reduced to approximately zero.

Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a partial cross-sectional configuration diagram of a secondary mirror rocking device according to an embodiment of the second invention, and FIG. 5 is a side cross-sectional view thereof.
FIG. 6 is a block diagram of the control system. In this example, the secondary mirror (lot) and the compensation plate (102> are respectively supported by the swing shaft (103) and <104> supported by the fixed part.
15(), the first and second secondary mirror drive coils <1050>, <105b> are arranged opposite to each other so as to be able to swing.
ot) and compensation play 1-<102>, the swing axis <103
) are attached to the secondary mirrors (101) on both sides of the first and second secondary mirror drive magnetic circuits <107n), (107b
) are attached to the compensation plays 1-(102) on both sides of the swing shaft (103>) between the secondary mirror (101) and the compensation plays 1-(102), and each secondary mirror drive coil (105n), (10
5b) respectively to generate attraction and repulsion forces, and the couple drives the secondary mirror (101) to swing. Also, the first and second
Compensation plate drive coil (106o), (106b)
is the swing axis (104) on the side opposite to the secondary mirror of the compensation plate (102).
) are attached to both sides of the first and second compensation plate drive magnetic circuits (llln), (111b> are fixedly arranged opposite to each compensation plate I/drive coil (106a), (106b), Each compensation plate drive coil (10
6a) and (106b), respectively, and the couple drives the compensation coil (102) to swing.

Next, the operation and effect will be explained. In the apparatus shown in FIGS. 4 to 6, the secondary mirror drive coil (105a>, (
105b) are connected in series or parallel to the IJ and twisted so that the same current flows in opposite directions.

Compensation plate drive coil (106n), (106b)
The same applies to During normal driving of the secondary mirror, a target signal is added to (rl), and zero is added to (r2). The secondary mirror <101) performs a rectangular wave-like oscillating motion in response to the target signal, and the compensation play 1-(102) oscillates in response to the reaction force of the secondary mirror drive magnetic circuit (107o) and (107b). Do exercise. At this time, the compensation plate (102>
operates to suppress the DC component of the rocking motion. The target signal (rl) is a signal that yields the optimum driving force waveform as shown in FIG. Position detection sensor (10
8>, (109) detects the swing angles of the secondary mirror (101) and the compensation play (102), respectively, and the control system feeds this back to determine the deviation from the target signals <"l" and (r2>). The secondary mirror (101) is driven with high accuracy (approximately 0.1%) in accordance with the target signal (l) in order to control the angle to zero.This device can perform the above-mentioned deflection operation. In addition to high-precision driving, the following effects can be achieved.

l) The secondary mirror (101) is swung by a couple, so conventionally 1
The ``bending force of the secondary mirror due to the coil and return spring'' that had been generated in the second mirror is now generated.

2) Since the swing angles of the secondary mirror (101) and compensation play 1-(102) are actively controlled by the control system, the secondary mirror (101)
01), the short transition time and large amplitude drive tends to stop.

In the above embodiment, the secondary mirror swinging device of the telescope has been described, but this may be an optical skitten device using a mirror or the like, and the same effects as in the above embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, the secondary mirror and the compensation plate 1, the secondary mirror and the compensation plate 1, which are arranged opposite to each other and are swingable about the rocking shafts supported by the fixed parts, respectively. The first and second secondary mirror drive coils are attached to the secondary mirrors on both sides of the swing axis between them, and the first and second secondary mirror drive coils are attached to the compensation plates on both sides of the swing axis between the secondary mirror and the compensation plate. 1st
, a second compensation play I/drive coil, which is fixedly arranged between the secondary mirror and the compensation plate, generates attraction and repulsion forces with each of the coils, and swings the secondary mirror and the compensation plate by a couple. first and second secondary mirror driving magnetic circuits;
and 1st. A second compensation plate driving magnetic circuit and a sensor for detecting the respective swing angles of the secondary mirror and the compensation plate are provided, and the current applied to each of the coils of the IJ is feedback-controlled based on the signal from the sensor. Therefore, according to another aspect of the present invention, the secondary mirror and the compensation plate are arranged opposite to each other and are swingable about the rocking shafts supported by the fixing parts, respectively, and the secondary mirror and the compensation plate are pivoted between the secondary mirror and the compensation plate. The first and second secondary mirror drive coils are respectively attached to the secondary mirrors on both sides of the moving axis, and the first and second secondary mirror drive coils are attached to the compensation plates on both sides of the swing axis between the secondary mirror and the compensation plate. First and second secondary mirror drive magnetic circuits generate attraction and repulsion forces between them respectively to swing the secondary mirror by a couple, and are attached to both sides of the swing axis on the side opposite to the secondary mirror of the compensation plate. first and second compensation plate drive coils;
First and second compensation plates that are fixedly arranged opposite to each of the compensation plate drive coils, generate attraction and repulsion forces with each of the compensation plate drive coils, and drive the compensation coils to swing by a couple force. It is equipped with a drive magnetic circuit and a sensor that detects the respective swing angles of the secondary mirror and compensation plate, and is configured so that the current applied to each coil is feedback-controlled based on the signal from the sensor, resulting in high speed and high accuracy. This has the advantage that large-amplitude secondary mirror drive can be realized with almost no vibration transmission to the outside of the device.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional configuration diagram of a secondary mirror rocking device according to an embodiment of the present invention, FIG. 2 is a side sectional view thereof, FIG. 3 is a block diagram of its control system, and FIG. A configuration diagram showing a sub-mirror swinging device according to another embodiment of the invention in terms of parts, FIG. 5 is a side sectional view thereof, and FIG. 6 is a control system block cI thereof.
Fig. 7 is a partially cross-sectional configuration diagram of a conventional secondary mirror swinging device, Fig. 8 is an enlarged configuration diagram of its spring return mechanism, and Fig. 9 is its control circuit diagram. Figure 10 shows the actieator and lol! FIG. 11 is a relationship diagram showing the force balance of the four adjustment spring devices, and a waveform chart showing the optimum driving force waveform of the secondary mirror. In the figure, (101) is a secondary mirror, (102) is a compensation plate, (103) and (104) are swing axes, <105
(1), (105b). (106o), (106b) are coil% (107
c+), (107b), (111o>, (1
1ib) is a magnetic circuit, (108) and (109) are position sensors, (110) is a base, (112) is a coil support, (121> is a transfer function from the driving force to the swing angle of the secondary mirror, (122) is the transfer function from the driving force to the swing angle of the compensation plate, (129), (130) is the sensor gain, (1278 (128>) is the stabilization compensator, (132
), (133) are control system loop gains. The same reference numerals in each figure indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A secondary mirror and a compensation plate that are arranged opposite to each other and are movable around a rocking shaft supported by a fixed part, and each is attached to the secondary mirrors on both sides of the rocking shaft between the secondary mirror and the compensation plate. first and second secondary mirror drive coils; first and second compensation plate drive coils respectively attached to the compensation plates on both sides of the swing axis between the secondary mirror and the compensation plate; and between the secondary mirror and the compensation plate. first and second secondary mirror driving magnetic circuits that are fixedly arranged and generate attractive and repulsive forces with the respective coils to swing the secondary mirror and the compensation plate by a couple; A secondary mirror oscillator is provided with a second compensation plate drive magnetic circuit, and a sensor for detecting the respective oscillation angles of the secondary mirror and the compensation plate, and is configured to feedback-control the current applied to each of the coils based on a signal from the sensor. motion device. (2) A secondary mirror and a compensation plate that are arranged opposite to each other and are movable around a rocking shaft each supported by a fixed part, and each is attached to the secondary mirrors on both sides of the rocking shaft between the secondary mirror and the compensation plate. The first and second secondary mirror drive coils are attached to the compensation plates on both sides of the swing axis between the secondary mirror and the compensation plate, and generate attraction and repulsion forces with each of the secondary mirror drive coils, respectively. A first unit that swings and drives the secondary mirror by a couple.
, a second secondary mirror drive magnetic circuit, first and second compensation plate drive coils attached to both sides of the swing axis on the side opposite to the secondary mirror of the compensation plate, and fixedly arranged opposite to each of the compensation plate drive coils. , first and second compensation plate drive magnetic circuits that respectively generate attraction and repulsion forces with each compensation plate drive coil to swing the compensation coil by a couple, and each of the secondary mirror and compensation plate. A secondary mirror rocking device comprising a sensor for detecting a rocking angle of the mirror, and configured to perform feedback control of a current applied to each of the coils based on a signal from the sensor.