JPH02221808A - Magnetic bearing gyro - Google Patents

Abstract

PURPOSE:To utilize the motion monitoring function provided to a magnetic bearing and to obtain a small-sized, high-reliability gyro with simple structure by providing a stator on the internal surface of a base opposite to a rotor whose end parts are both supported on the base through the magnetic bearings. CONSTITUTION:The stator 30 is provided on the internal surface of the base opposite to the rotor 21 whose end parts are both supported on the base 22 through the magnetic bearings. When external moment operates on the base 22 while the rotor 21 rotates fast around the base 22, the rotor 21 causes a presession and is to tilt at right angles to the operation direction of the external moment. Displacement sensors 31 detect the displacement of the rotor 21 at both end parts and send detection signals to a controller 40. The controller 40 sends a control current for making the rotor 21 coincident with a target reference position to the coil of the stator 30. The control current signal is sent to an arithmetic unit as well to calculate the direction and quantity of the presession from variation of the control current flowing through the coil of each stator magnetic pole. Further, the direction and quantity of the external moment operating on the base 22 are calculated from the arithmetic results.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic bearing gyro that is small, simple in structure, and has high drift performance.

[Prior Art] FIG. 4 is a conceptual diagram of a conventional uniaxial degree-of-freedom gyro. This gyro has a rotor 1 that rotates at high speed with a built-in motor.
In addition to the spin shaft 2 that supports the
It has 3. Then, the angular velocity or rotation angle around an axis (input axis) 4 perpendicular to both the output axis 3 and the spin axis 2 is output as the deflection angle of the output axis. In this case, the spin shaft 2 of the gyro is rotatably supported by the gimbal 7 via a rotor bearing 6. That Jinno\Lua is
An output shaft 3 perpendicular to the spin shaft 2 is rotatably supported on a base 5 via a gimbal bearing 8 .

When the rotor 1 is rotating at high speed and an external force moment as shown by arrow A acts on the input shaft 4, the rotor 1 causes preset in which it is tilted in a direction perpendicular to the direction in which the external force moment acts, and the gimbal 7 is displaced. . The displacement of the gimbal 7 is balanced by the spring 9, and the angle of rotation of the output shaft 3 in the direction of the arrow mark at that time is measured by the angle detector 10.

The performance of such a gyro can be evaluated by drift performance. Drift here refers to an error in the angular velocity around the axis that the gyro should originally detect. Efforts have been made to reduce this drift in gyros, but the uniaxial degree-of-freedom gyro shown in FIG. 4 has a rotor bearing 6. The gimbal bearing 8 is a ball bearing, and its frictional force prevents improvement in drift performance.

Therefore, a measure was taken to reduce friction by using a magnetic bearing, which is a non-contact type bearing, for the output shaft bearing (Precision Machinery, VOL 49, 12. P1701), and Figure 5 shows the low-friction type. This is a conceptual diagram of a gyro. A gimbal 7 that supports a rotor 1 via a spin shaft 2 is supported by a base 5 via a magnetic bearing 11 that supports a radial load and a pivot bearing 12 that supports a thrust load. The displacement of the gimbal 7 is measured by an angle detector 10 attached to the base 5. Also provided is a radial displacement detector 13 for magnetic bearings that detects radial displacement of the magnetic bearing.

[Problem to be solved by the invention]

In the conventional magnetic bearing gyro shown in Fig. 5 above,
Drift performance has been improved by reducing bearing resistance, but the use of magnetic bearings in this case is simply replacing ball bearings, and the purpose is to simplify the structure of the gyro and make it more compact. Then, the problem was that it did not contribute in any way.

The present invention has been made by focusing on the above-mentioned conventional problems, and its purpose is to utilize the motion monitoring function of magnetic bearings to create a magnetic bearing gyro that is simple in structure, small in size, and has high reliability. Our goal is to provide the following.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a rotor whose both ends are supported on a base via magnetic bearings, a stator attached to the inner surface of the base opposite to the circumferential surface of the rotor, and a displacement sensor that detects the position of the rotor in the radial direction in the magnetic bearing; a control device that sends a control current to the magnetic bearing according to the output of the displacement sensor; It consists of an arithmetic device that calculates the angular velocity acting on the base.

The magnetic bearing is preferably arranged such that the positions of the armature provided on the rotor and the stator magnetic poles provided on the base are shifted in the axial direction.

[Operation] When an external force moment acts on the base while the rotor is rotating at high speed around the base, the rotor causes preset and tends to tilt in a direction perpendicular to the direction in which the external force moment acts. This displacement of the rotor is detected by displacement sensors at both ends of the rotor, and the detection signal is sent to the control device.

Based on the input rotor displacement detection signal, the control device determines the control current value necessary to prevent rotor displacement and match the target reference position, and sends this control current to the coil of the stator pole of the magnetic bearing (stator The magnetic pole coils are arranged symmetrically around the rotor axis, facing each other in the X-axis direction and the Y-axis direction.

This control I current signal is also sent to the arithmetic unit. In response to this, the calculation device calculates the direction and amount of preset from the change in the control current flowing through the coils of each stator magnetic pole. Also, from the calculation results, the direction and amount of the external force moment acting on the base are calculated.

In this way, the rotor preset caused by the external force moment is detected as a change in the control current of the magnetic bearing, and the arithmetic unit calculates information on the external force moment based on the detected change in the control current of the magnetic bearing. Gyro does not require a gimbal. Furthermore, the angle detector used to detect the displacement of the gimbal is also unnecessary. Therefore, the structure is simple and can be miniaturized. Since the rotor is completely non-contact supported by magnetic bearings, drift performance is also improved.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show one embodiment of the present invention. FIG. 1 is a vertical cross-sectional view showing the configuration of the magnetic bearing gyro main body 20, in which the rotor 21 has a large diameter portion 21A with large inertia in the center, and rotor shafts 21B at both ends of the rotor.
is supported by a base 22 via a magnetic bearing S. That is, an armature 23 is attached to the outer circumferential surface of the rotor shaft 21B, and an armature 23 is attached to the inner circumferential surface of the rotor shaft through hole 22a of the base 22, facing the armature 23 in the radial direction with a bearing clearance therebetween. The stator poles 24 are attached. As shown in FIG. 2, the stator magnetic poles 24 are connected to the X axis,
It is configured with the Y axis. Then, a bias current ■ is caused to flow through the coil 27 connected to the DC power supply, and the armature 2
By forming a magnetic loop 28 between the bearings 3 and 3, a predetermined radial bearing clearance is maintained uniformly. Furthermore, the stator magnetic poles 24 receive a control current (2) from a control device 40, which will be described later. It is equipped with a control coil 29 that flows.

FIG. 2 shows an arrangement in which a control coil 29 is provided for causing a control current IC to flow between the stator magnetic poles 24 facing each other in the Y-axis direction. Furthermore, on the stator magnetic poles 24 facing in the X-axis direction,
A control coil is separately provided to flow a control current IC.

Furthermore, the stator magnetic pole 24 and armature 23 of this embodiment are as follows:
A so-called staggered arrangement is employed in which the relative positions in the axial direction are slightly shifted. As a result, an axial thrust force is also applied between the stator magnetic poles 24 and the armature 23, and the magnetic bearing S functions as both a radial bearing and a thrust bearing.

A stator 30 is attached to the inner surface 22b of the central portion of the base 22 so as to face the circumferential surface of the large diameter portion 21A of the rotor 21, and constitutes a motor that rotates the rotor 2I at high speed.

Displacement sensors 3 each detect the position of the rotor shaft 21B in the radial direction on the inner peripheral surface of the rotor shaft through hole 22a.
1 is placed. A sleeve 32 is attached to the rotor shaft 21B facing the displacement sensor 31 as a detected portion.

As shown in FIG. 3, the magnetic bearing gyro body 20 configured as described above is connected to a control device 40 that supplies a control current to the control coil 29 of the magnetic bearing gyro body 20 in accordance with the output of the displacement sensor 31. Further, an arithmetic unit 50 that calculates the angular velocity acting on the base 22 from the current value of the control current l outputted from the control device 40 is connected to the control device 40 via an ammeter 60.

Next, the action will be explained.

The coil of the stator 30 of the magnetic bearing gyro main body 20 is energized to rotate the rotor 21 at high speed.

In this state, when no external force moment acts on the magnetic bearing gyro main body 20, the rotor 21 rotates at the target reference position within the radial bearing clearance of the magnetic bearing S while its displacement is monitored by the displacement sensor 31. That is, the rotor 21 rotates with each bearing clearance between the armature 23 and the four stator magnetic poles 24 facing each other in the X-axis direction and the Y-axis direction maintaining the same standard spacing. The displacement sensor 31 detects the vibration of the rotor shaft 21B.

Now, the external force moment shown by arrow A in Fig. 1 is applied to the base 2.
2, the rotor 21 produces a preset according to the magnitude of the external force moment, and rotates and tilts in the direction indicated by the arrow mark around an axis J2 perpendicular to the input shaft J1.

This inclination is detected by a displacement sensor 31 arranged in the X-axis and Y-axis directions on the rotor shaft 21B. The displacement sensor 31 sends a displacement signal corresponding to the detected inclination of the rotor shaft 21B to the control device 40. Upon receiving the displacement signal, the control device 40 applies a control current (2) so as to cancel the displacement, prevent the rotor shaft 2 (2) B from tilting, and match the target reference position. is output via the ammeter 60 to the magnetic bearing stator magnetic poles 24 on both the left and right sides of the magnetic bearing gyro main body 20. Control current I
C flows through the control coil 29 of the stator magnetic pole 24 of the magnetic bearing and acts to change the magnetic flux of the magnetic loop 28 so that the bearing clearance matches the standard spacing. Rotor 21
Changes in the control current flowing through each stator magnetic pole 24 in the magnetic bearing S on both ends of the stator pole 24 are monitored by an ammeter 60,
Its control current1. The information is sent to the computing device 50. A system monitored by the arithmetic unit 50? By processing the Iif flow value, the angular velocity acting on the base 22 can be determined. It is also possible to find the declination angle by integrating the obtained angular velocity.

That is, the arithmetic unit 50, which has received the information on the control current I, determines from the change in the control current IC flowing through each stator magnetic pole 24 of each magnetic bearing S, in which direction and how much preset has occurred. The amount of external force moment acting on the base 22 in the direction is calculated.

Thus, according to this embodiment, the preset of the rotor 21 caused by an external force moment is detected as a change in the control current IC of the magnetic bearings S at both ends, and based on the change in the detected control current, the arithmetic unit 50 adjusts the external force moment. Calculate moment information.

Therefore, a gimbal such as a conventional magnetic bearing gyro and an angle detector used to detect displacement of the gimbal are unnecessary. Moreover, there is no need for a separate spin shaft bearing other than the magnetic bearing S. Therefore, the structure is simple and can be miniaturized. Moreover, since the rotor 21 itself is supported by magnetic bearings S in a completely non-contact manner instead of by conventional ball bearings, there is no bearing resistance (drift performance is also improved).

In the above embodiment, the magnetic bearing S is used as both a radial magnetic bearing and a thrust magnetic bearing, but the invention is not limited to this, and the radial magnetic bearing and the thrust magnetic bearing can be separated and separately It may be provided.

〔Effect of the invention〕

As explained above, according to the present invention, a magnetic bearing gyro main body is provided with a rotor whose both ends are supported by a base via magnetic bearings, and a rotor which is mounted on the inner surface of the base opposite to the circumferential surface of the rotor. It is formed by an attached stator and a displacement sensor that detects the position of the rotor in the radial direction in the magnetic bearing, and a control current is caused to flow through the magnetic bearing according to the output of the displacement sensor, and from the current value of the control current. It was configured to calculate the angular velocity of the external force moment acting on the base. Therefore, the conventionally required gimbals, ball bearings for the angle detector spin axis, etc. can be omitted, making it possible to provide a highly reliable magnetic bearing gyro with a simple structure, miniaturization, and improved drift performance. This effect can be obtained.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional view of the magnetic bearing gyro body, FIG. 2 is a cross-sectional view showing the structure of the magnetic bearing, and FIG. 3 is a f. FIG. 4 is a perspective view of a conventional one-degree-of-freedom gyro, and FIG. 5 is a vertical sectional view of a conventional magnetic bearing gyro. 20 is a magnetic bearing gyro main body, 21 is a rotor, 21B is a loaf shaft, 22 is a base, S is a magnetic bearing, 24 is a stator pole of the magnetic bearing, 30 is a stator, 40 is a control device, 5
0 is an arithmetic unit, and 6o is an ammeter.

Claims (2)

[Claims] (1) A rotor whose both ends are supported by a base via magnetic bearings, a stator mounted on the inner surface of the base opposite to the circumferential surface of the rotor, and a radial direction of the rotor in the magnetic bearing. A displacement sensor that detects a position, a control device that sends a control current to the magnetic bearing according to the output of the displacement sensor, and an angular velocity acting on the base from the current value of the control current output from the control device. A magnetic bearing gyro consisting of an arithmetic unit. (2) The magnetic bearing gyro according to claim 1, wherein the magnetic bearing is arranged such that the positions of the armature provided on the rotor and the stator magnetic poles provided on the base are shifted in the axial direction.