JP2003161321A - Posture control system of rotating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve vibration damping performance for a posture control system of a rotating device by adding posture control of vibration of a rotating shaft to active control thereof. <P>SOLUTION: Inside a casing 10, upper and lower fixing members 31, 32 are fitted and further magnetic bearings 11, 12, vibration sensors 3, 4, magnetic bearing 33 of thrust direction and a motor 34 are fitted. Both ends of a rotating shaft 30 are supported by the magnetic bearings 11, 12 and the rotating shaft is rotated by the motor 34, while generated vibration is subjected to the active control in the magnetic bearing 11, 12. Displacement sensors 35 are attached on four circumferential places of a bottom inside the casing 10 to detect displacement between bottoms of experimental boxes 20 to 23 and a bottom of the casing 10, so that inclination of posture of the rotating body is detected by the displacement to be added to the active control of the rotating body 30, thus improving the active control performance of the magnetic bearing 11, 12. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a posture control system for a rotating device, and is a system for effectively damping vibration by detecting the posture of a rotating body in addition to active control of vibration of the rotating device by a magnetic bearing. It is a thing.

[0002]

2. Description of the Related Art FIG. 7 is a plan view showing an example of a rotating device currently used in space. In the drawing, a rotating device 60 such as a motor has four supporting members 61, 62, 63, and
64 are attached and extend radially. Support member 61
Experiment boxes 70, 71, 72, 73 at the tip of ~ 64
Is attached, and an experiment object such as a plant is put in the experiment boxes 70 to 73. Such a device
In the zero-gravity state, a low speed rotation of about 1 rotation / sec is given by the rotating device 60, and the experiment of the objects in the experiment boxes 70 to 73 is performed.

In the rotating device as described above, the supporting member 61 is used.
Experimental boxes 70 to 73 are attached to the tips of ~ 64, and the tips have a large shape. Also, Experiment Box 7
Experiment objects of different types for applying gravity are stored in 0 to 73, and the sizes of the experiment objects are also different, and although the entire device is symmetrically arranged about the rotation axis center, the experiment objects to be stored are Is unbalanced. Therefore, the rotation causes vibrations in the support members 61 to 64 and the experiment boxes 70 to 73, and when the vibrations occur, the experiment object is changed or adversely affected.

[0004]

As described above, the conventional rotating device in space generates vibration during rotation and gives vibrations to the arms and the experiment box that form the rotating body, which adversely affects the object to be experimented. Was affecting. Further, these vibrations propagate to the surrounding environment via the rotating shaft, affect the surrounding space equipment, and also affect the control of the equipment.
Therefore, the applicant of the present invention has proposed a rotating device in which a magnetic bearing is used for the rotating shaft in order to suppress such vibration of the rotating device. The outline will be described below.

FIG. 5 shows a rotating device proposed by the applicant of the present invention, in which (a) is a side view and (b) is B- in (a).
FIG. 6C is a sectional view taken along the line C-C of FIG. In FIG. 1A, reference numeral 10 denotes a casing that houses the entire rotating body, and the casing 10 has spaces 10a and 10b provided at the top and bottom. Magnetic bearings 11 and 12 are arranged around the upper and lower spaces 10a and 10b. The spaces 10a, 1
It is also possible to directly connect the magnetic bearing to the casing without providing 0b and the like.

The magnetic bearings 11 and 12 each have a space 10
Exciting coils 1 and 2 are arranged around the insides of a and 10b to form a magnetic bearing. Spaces 3 and 4 are 10
The vibration sensors are arranged inside the coils 1 and 2 in a and 10b, and can detect the displacement of the gap between the rotating shaft 30 and the vibration of the rotating shaft 30 from this displacement as described later. It is a thing. As shown in FIG. 7C, four vibration sensors 3 and 4 are symmetrically arranged around the periphery, and are configured to detect the vibration displacement of the rotary shaft 30 in the ± X and ± Y directions.

Reference numeral 30 denotes the above-mentioned rotary shaft, both ends of which are arranged in the spaces 10a and 10b, respectively, which are connected to the motor 13, and both ends of which are axially supported by the magnetic bearings 11 and 12. Therefore, the rotating shaft 30 is supported by the space by magnetic force with a predetermined gap maintained between the rotating shaft 30 and the coils 1 and 2, and is rotated by the motor 13. Around the rotation axis, as shown in Figure (b),
It is fixed by four arms 24, 25, 26, 27 in the X and Y axis directions, extends horizontally, and the experimental box 20, 2 is attached to the tip.
1, 22, 23 are attached.

In the above rotating device, the experimental box 2
An object to be experimented to add gravity, that is, a plant or an animal, is placed in 0 to 23, and the motor 13 is driven to rotate at a low speed in a space environment to grow a plant in space. Experiments are conducted to observe the situation and the survival situation of animals. Since the experiment boxes 20 to 23 store the experiment items having different shapes, sizes, and weights in this manner,
When rotated, a difference occurs in the acceleration generated due to the imbalance of the weight between the experimental boxes 20 to 23, and vibration is generated between the boxes. This vibration is transmitted to the arms 24 to 27 and vibrates the rotary shaft 30, and this vibration is transmitted from the bearing portion to the casing 10 and propagated to the external environment, which adversely affects the surroundings.

In the above rotating device, the bearing of the rotary shaft 30 is the magnetic bearings 11 and 12, and the rotary shaft 30 is the casing 10.
It is configured to support by magnetic force without contacting the support part of
When vibration is generated on the rotating shaft 30, the vibration is generated on the rotating shaft 30.
Four vibration sensors 3 and 4 arranged on the X and Y axes around both ends
Detect with. In the vibration sensors 3 and 4, as will be described later,
When a gap change due to the vibration between the rotary shaft 30 and the sensor is detected and input to the control device, and the control device reduces the gap, the current at the positions of the coils 1 and 2 corresponding to return the gap to the original gap. Is controlled so that the vibration is absorbed.

Although the coils 1 and 2 are not shown,
For example, four independent windings for each coil
It is arranged so that the magnetic force acts in the four directions of the axis and the Y-axis, and the displacement of the coil is large in accordance with the displacement due to the inclination of the rotating shaft 30, and the coil at the position where the gap between the coil and the coil varies the most is excited. The repulsive force with respect to the rotating shaft 30 or the suction force is adjusted to absorb the displacement due to vibration.

FIG. 6 is a system diagram of control of the rotating device described above. The vibration sensors 3a, 3b, 3c and 3d are arranged around the upper end of the rotary shaft 30 and the vibration sensors 4a and 4 at the lower end.
The detection signals from b, 4c and 4d are input to the control device 14. The controller 14 drives the motor 13 and monitors the displacement of each of the vibration sensors 3 and 4 due to the vibration of the rotary shaft end in the X and Y axis directions, and the gap between the sensor and the rotary shaft becomes smaller or larger. Then, the exciting currents of the windings of the coils 1 and 2 at the corresponding positions on the X and Y axes are controlled, and the repulsive force or the attractive force between the rotating shaft 30 and the coil between them is strengthened to return the gap to its original position. Let

Reference numeral 15 denotes a storage device in which a required value pattern of amplitude or acceleration with respect to the vibration frequency is stored in advance as data.
When monitoring the vibration of the rotating shaft 30 from 4, the rotating shaft is displaced and the vibration becomes large compared with this required value, and if the vibration exceeds the required value, the exciting current of the coil is controlled. The vibration is absorbed and the vibration of the rotating shaft 30 is constantly controlled so as to be equal to or less than the required value. The storage device 15 can be replaced with a memory. Further, the bearing control device is not connected to the storage device 15, and can control the vibration of the bearing by data based on the displacement and acceleration of the bearing.

In the rotating device described above, both ends of the rotating shaft 30 are supported by the magnetic bearings 11 and 12 to suppress the vibration generated due to the imbalance of the mass of the experimental boxes 20 to 23. It has become possible to significantly reduce the vibration transmitted to the rotating device. However, even in the vibration suppression using such a magnetic bearing, there is a limit in performing complete vibration suppression in all vibration modes, and the vibration of the rotating shaft 30 is transmitted to the casing 10 to the external space environment. It had an impact.

Therefore, according to the present invention, both ends of the rotary shaft are supported by magnetic bearings, and the displacement of the rotary body composed of the rotary shaft and the experiment box is also detected, so that both active vibration suppression by the magnetic bearing and attitude control of the rotary body are performed. It is an object of the present invention to provide an attitude control system for a rotating device that can effectively suppress the vibration of the rotating device by controlling the above.

[0015]

The present invention provides the following means for solving the above-mentioned problems.

(1) A rotary shaft, which is driven by a motor in a casing and has a plurality of boxes for accommodating a plurality of objects for applying gravity to the surroundings, is attached to the casing by being fixed to the casing. Magnetic bearings that support both ends, vibration sensors that are fixed to the casings near the magnetic bearings at both ends and that detect gaps between the rotating shafts, and a plurality of vibration sensors are arranged around the bottom surface of the casing. , A displacement sensor for detecting a distance between the box and the bottom surface of the box, and a signal from the displacement sensor is taken to obtain a displacement from a reference value of the detected distance, and an attitude signal of a rotating body including the box is obtained from the displacement. The controller that calculates and outputs the posture signal of the rotating body from the controller and the signal of the gap from the vibration sensor are also taken in respectively, and either of these signals exceeds the reference value. Attitude control system of the rotary apparatus characterized by comprising comprises a an active control system the control current of the exciting coil of the magnetic bearing to control the vibration of the rotary shaft and the corresponding are.

(2) The attitude control system for a rotating device according to (1), wherein the displacement sensor for detecting the distance to the bottom surface of the box is a displacement sensor using laser light.

(3) The posture of the rotating device according to (1), wherein the displacement sensor for detecting the distance to the bottom surface of the box is a displacement sensor using a photodiode, CdS, or a phototransistor. Control system.

(4) The attitude control system for a rotating device according to (1), wherein the displacement sensor for detecting the distance to the bottom surface of the box is a displacement sensor using a position detector composed of a potentiometer. .

The present invention (1) is based on the above system.
Vibration during rotation caused by unbalance of the weight of the experimental object in the box is detected by the vibration sensor, and the active controller controls the current of the exciting coil of the magnetic bearing to absorb the vibration transmitted to the rotating shaft. Further, the distance from the bottom surface of the box is detected by the displacement sensor and input to the control device, and the control device takes the difference between this distance and the reference value and outputs it as an attitude signal to the active control device. In the active control device, this attitude signal is compared with a previously accepted reference value, and if the attitude signal is larger than the reference value, it is determined that the bottom surface of the box is inclined from the bottom surface of the casing and the rotation axis is also inclined. The active control of the magnetic bearing is performed, and the current of the exciting coil of the magnetic bearing corresponding to the location where the displacement of the vibration sensor is large is controlled to suppress the rotation shaft.

Therefore, the active control device controls the magnetic field when the displacement from the vibration sensor is larger than the reference value or when the displacement from the displacement sensor is large and the posture signal of the rotating body is larger than the reference value. Since the bearing is actively controlled, the vibration of the rotating shaft is effectively suppressed.

In (2) of the present invention, since the displacement sensor uses a laser beam, (3) uses a photodiode, CdS or a phototransistor, and (4) uses a potentiometer, its application range is expanded.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is an internal cross-sectional view of an attitude control system for a rotating device according to a first embodiment of the present invention. In the drawing, spaces 10a and 10b are formed inside the casing 10, a cylindrical upper fixing member 31 is attached to the space 10a, and a radial direction of the rotary shaft 30 is provided around a circle of the upper fixing member 31. As in the example of FIG. 5, four magnetic bearings 11 supporting the above and vibration sensors 3 are attached respectively. Further, a thrust magnetic bearing 33 for supporting the rotating shaft 30 in the thrust direction is also attached.

A lower fixing member 32 is mounted in the space 10b, and four vibration sensors 4 or displacement sensors, each of which is arranged in the right angle direction, are arranged around the inside of the lower fixing member 32 in the radial direction of the rotary shaft 30. Magnetic bearings 12 are attached respectively. Also, on the bottom surface of the space 10b, the rotating shaft 30
A motor 34 for rotating and driving is attached. In addition,
The motor 34 may be attached not to the inside of the rotating device but to the outside. In this case, there is an advantage that the motor 34 can be easily maintained and inspected.

Further, as will be described later with reference to FIGS. 2 and 3, four displacement sensors 35 are circumferentially arranged at equal intervals on the bottom surface inside the casing 10. The displacement sensor 35 emits a laser beam, a light beam, an electromagnetic wave, an ultrasonic wave, or the like, receives a reflected wave from the bottom surface of the experiment box, measures the displacement from the casing 10 on the bottom surface, and rotates the rotary shaft 30 and the arm 2.
4 to 27 and the experiment boxes 20 to 23 are used to measure the tilt of the rotating body. The tilt is calculated by sending the measurement result to a controller (not shown). The control device is attached to the outside of the casing 10. In addition to the above, a photodiode, CdS, phototransistor, or the like may be used as the displacement sensor, and a potentiometer or the like may be used as the detector.

Both ends of the rotary shaft 30 are supported by the magnetic bearings 11 and 12 as described above, and the magnetic bearing 33 for thrust is used.
The position in the thrust direction is regulated by, and the gaps at both ends are detected by the vibration sensors 3 and 4, respectively. As described with reference to FIG. It is controlled by the control device 14 so as to absorb the vibration. Further, as described above, the posture of the rotating body is also measured based on the signal from the displacement sensor 35 and reflected in the active control of the magnetic bearing.

FIG. 2 is a sectional view taken along line AA in FIG.
Four displacement sensors 35a, 3a are provided on the bottom surface of the casing 10.
5b, 35c, and 35d are arranged at 90-degree intervals, respectively, and are arranged so as to emit a beam to the bottom surface of the experimental box that passes by rotating the top surface and receive the reflected wave. It should be noted that there are four experimental boxes in FIG.
In the above example, eight examples are shown, but the number may be any number, and any number of rotating devices may be used.
The number of displacement sensors 35 need not be four, and may be increased or decreased as necessary.

FIG. 3 is a system diagram of control according to the embodiment of the present invention. The magnetic bearings 11 and 12, vibration sensors 3a and 3b, and
3c, 3d, 4a, 4b, 4c, 4d, control device 14,
The configuration of the storage device 15 and the contents of active control of the magnetic bearings 11 and 12 by the control device 14 based on the detection signals of the vibration sensors 3 and 4 are the same as those described in FIG. In the present invention, in addition to this active control, the displacement sensor 35a,
35b, 35c, 35d and the posture control of the rotating body by the control device 36 are added to improve the vibration damping performance.

That is, the displacement sensors 35a to 35d receive beam reflected waves from the bottom surface of the experiment box passing therethrough at four locations arranged on orthogonal axes, and from the round trip time, the bottom surface of the casing 10 and the bottom surface of the experiment box are detected. The distance to and is measured and output to the control device 36. This distance is compared with the reference distance in the horizontal arrangement by the controller 36,
The displacement is measured. With respect to the displacement signals measured at the four locations, the controller 36 determines the inclination of the rotor from the displacements at the four locations. The inclination of this rotating body is the casing 1 when the bottom surfaces of a plurality of experimental boxes are made into one plane.
0 is the inclination from the bottom surface, and is also the inclination of the rotation axis 30 when the rotation axis 30 is orthogonal to the bottom surface of the experiment box.

The signal of the inclination of the rotating body obtained by the control device 36, that is, the attitude signal is sent to the control device 14 which controls the rotating shaft 30, and when the control device 14 actively controls the magnetic bearings 11 and 12. Vibration sensors 3a-3d, 4a-4d
In addition to the control of the magnetic bearings 11 and 12, the magnetic bearings 11 and 12 are also controlled in consideration of the inclination of the posture control of the rotating body based on the signals of the displacement sensors 35a to 35d.

FIG. 4 is a flow chart of control in the embodiment of the present invention. In the figure, control on the right side [Y]
Is the active control by the control device 14 of the magnetic bearings 11 and 12, and the left control [X] is the attitude control by the control device 36 by the displacement sensors 35a to 35d.

In the figure, in the control [Y], after the start, in step S1, the control device 14 takes in the signals of the vibration sensors 3a to 3d, 4a to 4d, and at the ends of the rotary shaft 30, at the position of each sensor. Find the deviation of the rotation axis. Next, in S2, a deviation α between the gap at the normal position and the signal of the gap including the measured deviation is obtained in each sensor position, and in S3, it can be selected whether or not the deviation α is larger than a preset reference value. .

Next, in S4, when the deviation α is large, the current of the exciting coil of the magnetic bearing at the position corresponding to the vibration sensor is adjusted, and the rotating shaft 30 is controlled to be restored to the central position. If the deviation α is smaller than the reference value in S3, the vibration suppression control is not necessary, and therefore the process returns to S1 again to continue the control. The control of S1, S2 and S3 is 4
The same operation is performed in all the vibration sensors 3a to 3d and 4a to 4d, and when the control at the positions of all the vibration sensors is completed, the process proceeds to the next S6.

In S5, it is checked whether or not the rotary shaft 30 has been restored to the center position. If it has not been restored to the center position, the process returns to S4 to control and restore the current of the exciting coil of the corresponding magnetic bearing. If so, if the operation is continuing in S6, the process returns to S1 and the control is repeated. If the operation is completed, the process ends in S7. Such a magnetic bearing 1
Even if the rotary shaft 30 is vibrated by the active control of 1 and 12 and the rotary shaft is displaced, the rotary shaft 30 can be returned to the center position.

In the present invention, control [X] is further added. That is, in S8, the control device 36 obtains the distance between the bottom surface of the experiment box and the bottom surface of the casing 10 by the displacement sensors 35a to 35d arranged at four orthogonal positions. Find the slope of. The deviation β from the preset reference value of the inclination of the rotating body calculated in S9 is calculated, and this value is sent to the control device 14.

The control unit 14 selects whether or not this deviation β is larger than a reference value which is allowed in advance. When this deviation is large, the process proceeds to S4, and the exciting coil of the magnetic bearing in which the deviation has occurred is vibrated correspondingly. In accordance with the signal from the sensor, the exciting current is adjusted in the same manner as the above-described control during active vibration damping to return the position of the rotary shaft 30 to the normal center position. Also, S
In 10, when the deviation β is small, the process returns to S8 and the control is repeated again.

In the embodiment of the present invention, the active vibration damping control of the rotary shaft 30 is performed by the control device 14 of the control [Y] by the signal from the vibration sensor, and the control [X] is performed separately from this control. In the controller 36, the inclination of the posture of the rotating body is detected by the signals from the displacement sensors 35 to 35d, and the magnetic bearing 1 is also detected based on the result of the posture control.
Since the active control of the magnetic bearings 1 and 12 is performed, the magnetic bearings 11 and 1
The vibration damping control of No. 2 is performed by any one of the control [X] and the control [Y], and the vibration damping performance is improved.

[0038]

EFFECTS OF THE INVENTION The attitude control system for a rotating device according to the present invention comprises (1) a rotary shaft mounted with a plurality of boxes which are driven to rotate by a motor in a casing and contain a plurality of objects for applying gravity to the surroundings. A magnetic sensor having a magnetic bearing fixed to the casing and supporting both ends of the rotary shaft, and a vibration sensor fixed to the casing near the magnetic bearings at the both ends and detecting a gap between the rotary shaft and the magnetic bearing. A plurality of displacement sensors arranged around the bottom surface of the casing to detect the distance between the bottom surface of the box and the displacement sensor, and a signal from the displacement sensor is acquired to obtain the displacement from the reference value of the detected distance. A controller that calculates and outputs a posture signal of the rotating body including the box from the same displacement, and a posture signal of the rotating body from the controller and a gap signal from the vibration sensor, respectively. However, when any one of these signals exceeds a reference value, an active control device for controlling the current of the corresponding exciting coil of the magnetic bearing to control the vibration of the rotating shaft is provided. .

According to (1) of the present invention, due to the above-mentioned structure, the vibration during rotation generated by the imbalance of the weight of the experimental object in the box is detected by the vibration sensor, and the active control device causes the exciting coil of the magnetic bearing to move. The current is controlled to absorb the vibration transmitted to the rotating shaft. Further, the distance from the bottom surface of the box is detected by the displacement sensor and input to the control device, and the control device takes the difference between this distance and the reference value and outputs it as an attitude signal to the active control device. In an active controller,
If this attitude signal is compared with a reference value that is allowed in advance, and if the attitude signal is larger than the reference value, it is determined that the bottom surface of the box is tilted from the bottom surface of the casing, and the rotating shaft is also tilted, and the magnetic bearing active Control is performed to control the current of the exciting coil of the magnetic bearing corresponding to a location where the displacement of the vibration sensor is large, and the rotation axis is damped.

Therefore, the active control device controls the magnetic field when the displacement from the vibration sensor is larger than the reference value or when the displacement from the displacement sensor is large and the posture signal of the rotating body is larger than the reference value. Since the bearing is actively controlled, the vibration of the rotating shaft is effectively suppressed.

In (2) of the present invention, the displacement sensor uses a laser beam, in (3) a photodiode, CdS or a phototransistor, and in (4) a potentiometer, so the range of application is expanded.

[Brief description of drawings]

FIG. 1 is an internal cross-sectional view of a rotating device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a system diagram of control according to an embodiment of the present invention.

FIG. 4 is a flowchart of control of the control device according to the embodiment of the present invention.

FIG. 5 shows a rotating device according to the prior art of the present invention,
(A) is a side view of the inside, (b) is BB in (a)
FIG. 6C is a sectional view taken along the line C-C in FIG.

FIG. 6 is a control system diagram of the rotating device shown in FIG.

FIG. 7 is a plan view of a rotary experiment device in space.

[Explanation of symbols] 3,4 Vibration sensor 10 casing 11, 12, 33 Magnetic bearing 14,36 Control device 15 Memory device 20-23 experiment box 24-27 arms 30 rotation axis 31 Upper fixing material 32 Lower fixing material 34 motor 35 Displacement sensor

Claims (4)

[Claims] 1. A rotary shaft, which is driven by a motor in a casing and has a plurality of boxes for accommodating a plurality of objects for applying gravity to the surroundings, the rotary shaft being fixed to the casing and both ends of the rotary shaft. A magnetic bearing that supports the portion, a displacement sensor or a vibration sensor that is fixed to the casing in the vicinity of the magnetic bearings at both ends and that detects a gap between the rotary shaft, and a plurality of sensors around the bottom surface inside the casing. A displacement sensor that is arranged to detect the distance between the box and the bottom surface of the box, and a signal from the displacement sensor is acquired to obtain a displacement from a reference value of the detected distance, and the posture of the rotating body including the box from the displacement. A control device that calculates and outputs a signal, a posture signal of the rotating body from the control device, and a gap signal from the vibration sensor are respectively taken in, and either of these signals is used as a reference. An attitude control system for a rotating device, comprising: an active control device that controls a current of an exciting coil of the magnetic bearing corresponding to a value exceeding the value to control vibration of the rotating shaft. 2. The attitude control system for a rotating device according to claim 1, wherein the displacement sensor that detects the distance to the bottom surface of the box is a displacement sensor that uses laser light. 3. The attitude control of a rotating device according to claim 1, wherein the displacement sensor that detects the distance to the bottom surface of the box is a displacement sensor that uses a photodiode, CdS, or a phototransistor. system. 4. The displacement sensor for detecting the distance from the bottom surface of the box is a displacement sensor using a position detector composed of a potentiometer.
Attitude control system for the rotating device described.