JPH07118845B2 - Attitude control mechanism for magnetic levitation movement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) [0001] The present invention relates to a magnetic levitation transfer attitude control mechanism for levitating and transporting an object to be transported.

(Prior Art) The development of a train using magnetic levitation is well known. Since the transfer using the magnetic levitation is non-contact, dust is not generated and it is attracting attention for automatic transfer of objects in an ultra-clean room, for example, automatic transfer of semiconductor wafers.

In such magnetic levitation transportation, it is extremely important to control the posture of the moving body.

The magnetic levitation transport device generally has three axes depending on how many degrees of freedom other than one degree of freedom in the moving direction among the six degrees of freedom in the three-dimensional space of the moving body moving in a three-dimensional space are controlled. It is classified into a control type and a 5-axis control type.

The 3-axis control type is a type that controls vertical, roll (tilt left and right), and pitch (tilt front and back) by a servo.
In addition to the 3-axis control type, the axis control type is a type that servo-controls left and right and yaw (in-plane rotation).

The three-axis control type moves by the horizontal component of the attraction force of the magnetic circuit system (levitation electromagnet) used for levitation so that it does not come off the magnetic guide rails that indicate the movement path. The displacement is large because it is not controlled by the left and right or yaw position detection results, and its settling is slow because it depends on the loss of the magnetic circuit. On the other hand, in the 5-axis control type, since all the degrees of freedom except the movement direction are controlled by the servo, it is possible to move while keeping its posture always stable.

FIG. 5 shows a cross-sectional view of a conventional 5-axis control type magnetic levitation transport device perpendicular to the moving direction. Reference numeral 11 is a magnetic guide rail, 12 is a moving body, 13 is a levitation electromagnet, and 14 and 15 are left and right control electromagnets. On the moving body 12, at least another set of electromagnets having the same shape as those of the above-described 13, 14, 15 and having the same function are arranged at intervals in the moving direction, ie, two or more sets in total. Further, on the moving body 12, there is a position detector and a control circuit having five degrees of freedom (not shown), which controls the flying height.

Here, 14 and 15 are for directly attracting the magnetic guide rails, so that 14 is the moving body in the left direction and 15 is the moving body in the right direction.
Generates the force to move 12. Therefore, considering the efficiency of the magnetic circuit of the electromagnet, the gap between the magnetic body guide rail 11 and the left and right control electromagnets 14 and 15 cannot be made large.

(Problems to be solved by the invention) Conventionally, a left / right control electromagnet for controlling left / right and yaw is arranged so that a magnetic guide rail is sandwiched from the left and right sides of the rail, and an attractive force generated from this is used. Also, the lateral position detector also measures the gap between the magnetic guide rail and the electromagnet from the lateral direction by using an eddy current sensor or the like. Therefore, considering the efficiency of the left and right control electromagnets and the detection capability of the left and right position detectors, it is difficult to make a large gap between the magnetic guide rail and the left and right control electromagnets and the left and right position detectors. There was no, but it was difficult to turn in a small radius.

The present invention has been made in view of the above circumstances, and is premised on a magnetic levitation moving device that magnetically levitates a moving body with respect to a guide rail and travels along the guide rail in a non-contact manner. Due to the appropriate arrangement with the position control electromagnet, of the six degrees of freedom of the tertiary space of the mobile body, the five degrees of freedom except the traveling direction along the guide rail are properly restrained, and the guide rail of the mobile body is restrained. It is an object of the present invention to provide an attitude control mechanism for magnetic levitation movement that enables efficient and stable linear traveling movement along the same, and that allows the moving body to travel along a guide rail portion having a small radius. .

[Structure of Invention]

(Means for Solving the Problem) In the magnetic movement attitude control mechanism of the present invention, the moving body is magnetically levitated with respect to the guide rail by the magnetic levitation electromagnet and guided in the left and right direction by the left and right position control electromagnets. In a magnetic levitation moving device that travels along the guide rails in a non-contact manner, the magnetic levitation electromagnet and the position control electromagnet are provided at upper and lower portions facing each other across the guide rails at left and right portions of the moving body, The magnetic gap between the left and right position control electromagnets and the guide rails in the magnetic circuit is formed in the vertical direction, and the magnetic path cross-sectional area of the magnetic gap changes according to the lateral displacement of the moving body. The left and right position control electromagnets are vertically oriented on the left and right guide edges of the guide rail.

(Operation) In the attitude control device for magnetic levitation movement having the above-mentioned configuration, the air levitation electromagnet and the position control electromagnet are arranged at the upper and lower portions of the moving body, which are opposed to each other with the guide rails interposed therebetween. A magnetic circuit is formed between the guide rail and the moving body so that the moving body itself is magnetically levitated / guided with respect to the guide rail to travel without contact. As a result, no dust is generated due to the traveling movement of the moving body, which is very suitable for automatic transfer of objects in an ultra-clean room, such as for automatic transfer of semiconductor wafers.

Further, when controlling the magnetic levitation of the moving body, the electromagnet for lateral position control acts against the magnetic levitation electromagnet to positively pull down the moving body in addition to gravity.
The levitation amount of the moving body can be freely controlled by simply controlling the currents of the magnetic levitation electromagnets and the left and right position control electromagnets that face each other with the guide rail sandwiched between them, and the guide rail installation direction Has many degrees of freedom as well as the horizontal direction orthogonal to gravity (vertical direction),
When the position control of the moving body in the left-right direction is performed, it does not change in the up-down direction, the efficiency of the magnetic field is improved, and the moving body can travel along a guide rail portion having a small radius.

Further, in the case of the present application, the width of the left and right guide edge portions of the guide rail drawn into the magnetic path is changed by changing the current balance given to the left and right position control electromagnets, and the horizontal position of the moving body is changed. It is possible to decide arbitrarily.

(Example) Next, the Example of the attitude | position control mechanism of this invention is described with reference to drawings.

A guide rail 21 made of a magnetic material having a T-shaped cross section is fixedly laid on the floor surface 22 with a desired length. The moving body 24 travels along the guide of the guide portion 23 of the guide rail 21. This mobile
The configuration of 24 is such that the cross section is in the shape of a letter having a notch on the bottom so as to surround the guide portion 23, and the bottom 25 has an opening 26 in the laying direction of the rail 21.

Such a moving body 24 moves by the following magnetic circuit. That is, magnetic field generating means for magnetic levitation, for example, magnetic levitation electromagnet rows 27 and 28 are moved in two rows at predetermined intervals on both inner wall surfaces of the bottom surface 25 of the moving body 24 facing the lower surface of the guide portion 23. Is laid in the direction. Further, the position control is as follows in the direction perpendicular to the moving direction of the moving body 24 which is the position-controlled body. In this embodiment, position control in the left-right direction is performed by the following configuration. A magnetic gap is formed in a direction 30 perpendicular to the position control direction 29 of the position-controlled body.

For example, the position control electromagnets 31 and 32 are fixed to the inner wall surface of the moving body 24 at symmetrical positions on the upper surface side of the guide portion 23. The electromagnets 31 and 32 and the guide portion 23 are constructed as shown in FIGS. 2 (A) and 2 (B). That is, the yoke 3
3, 34 are formed in a U-shaped cross section, and one end is formed wide especially. Electromagnetic coils 35, 36, 3 on each core piece
The electromagnets 31 and 32 are formed by winding 7 and 38, respectively. The magnetic fields generated from the electromagnetic coils 35, 36, 37, 38 pass through the respective cores 33, 34 and the magnetic gaps 39, 40 to form closed magnetic paths 41, 42 with the guide portion 23, respectively.

The relationship between the electromagnets 31 and 32 and the guide portion 23 is
The edge portion 43 of 23 is set at a position where it opposes at a substantially intermediate position 44 of the wide-side yoke portions of the electromagnetic coils 31 and 32.

Therefore, the magnetic gaps 39, 40 are formed between the end surfaces of the yokes 33, 34 and the facing surfaces of the guide portion 23. This magnetic gap 3
The cross-sectional areas of the magnetic paths of 9 and 40 change depending on the position change of the moving body in the left-right direction. On the other hand, the electromagnet, by its nature, always generates a force in the direction of reducing the magnetic resistance of the magnetic path. That is,
A force is generated in the direction in which the cross-sectional area of the magnetic path increases. Therefore, the left / right position can be controlled by changing the balance of the currents applied to the electromagnets 31, 32 according to the input from the left / right position detector. 2A and 2B show a state in which the moving body 24 has moved to the left and right with respect to the paper surface, respectively. The left and right position control electromagnets 27 may be provided not only at the upper side but also at the lower side, or may be provided at both the upper and lower sides.

Further, the relationship between the guide rail 21 and the moving body 24 need not be described, but the moving body 24 is configured as a guide rail and the guide rail 21 is configured as a moving body in a relative relationship as shown in FIG. It is needless to say that can be realized if the relative magnetic field relationship is established.

The point of using at least two sets of these electromagnets is as described in the conventional example.

In FIG. 1, what is different from FIG. 5 is the shape and arrangement of the left and right position control electromagnets.

In FIG. 5, the lateral displacement of the moving body 12 causes the distance between the direct magnetic body guide rail 11 and the yokes of the left and right position control electromagnets 14 and 15 to be displaced, whereas in FIG. The lateral displacement of the moving body 2 changes the amount of overlap between the magnetic body guide rail 21 and the yokes of the lateral direction control electromagnets 31 and 32. That is, the magnetic resistance continuously changes from the state in which the magnetic resistance shown in FIG. 2a is small to the state in which the magnetic resistance shown in FIG. 2b is large. In other words, the cross-sectional area of the magnetic path in the magnetic gap changes. Since the electromagnet generates a force in the direction of reducing the magnetic resistance of its magnetic circuit, the electromagnet 31,
32 is an electromagnet for left and right position control. Further, since the two left and right position control electromagnets 31 and 32 are respectively arranged symmetrically with respect to the magnetic guide rail 21, it is possible to generate forces in directions opposite to each other. Also, the left and right control electromagnets simultaneously generate a force in the direction of shortening the gap (vertical direction), but this is canceled by the levitation electromagnets that face the left and right control electromagnets with the magnetic guide rails facing each other. It is possible. Left / right position control electromagnet 3
Reference numerals 1 and 32 have a configuration in which electromagnetic coils are wound around U-shaped cores each having a wide core on the outside. Further, in the magnetic levitation guide, a permanent magnet is also used as a part of the yoke of the levitation electromagnet, and the electromagnet is used for absorbing the disturbance to change the levitation amount and control so that the force of the permanent magnet is used for balancing. There is a method called the zero power control method,
Also in this method, the attitude control mechanism using the left and right control electromagnets can be used in this embodiment.

FIG. 3 shows an example of a left and right position detector for enhancing the effect of the present invention.

A light emitting element array 51 and a light receiving element array 52 are arranged in the guide portion 23 of the magnetic guide rail 21 so as to face the upper and lower surfaces thereof, and both are attached to a moving body (not shown). A part of the light emitted from the light emitting element array 51 is generated by the magnetic guide rail 51.
It is arranged to be partially blocked by.

Therefore, by comparing the output of the light-receiving element array 43 with a preset set value, the left-right position of the moving body can be known. The amount of current supplied to the electromagnetic coils 35, 36, 37, 38 is controlled so as to compensate for the amount of deviation due to this position detection. In addition, by arranging two left and right position detectors at intervals in the moving direction in correspondence with the aforementioned electromagnet group,
It is possible to detect yaw.

FIG. 4 shows another embodiment of the magnetic circuit for left / right position control shown in FIG. 2, which is an example in which a magnetic gap G is formed between the upper and lower surfaces of the guide rail 21. That is, an electromagnetic coil 53 is provided on the side of the guide rail 21, and the magnetic field generated by the electromagnetic coil 53 is guided by the annular core 54 so as to pass through the upper and lower surfaces of the guide portion 23 of the guide rail 21. is there.

In the above embodiment, an example in which the moving body 24 having a U-shaped cross section is arranged outside has been described.
It goes without saying that the structure may be arranged inside. Further, in the above-mentioned embodiment, an example of magnetically levitating against the gravity of the moving body has been described, but as long as it is a means for levitating movement by magnetic force, it is not always the case shown in FIGS.
It goes without saying that the same effect can be obtained not only by the configuration as shown in the drawing but also by the configuration obtained by rotating the configuration of FIGS. 1 and 4 by 90 degrees.

In short, the magnetic gap provided in the magnetic circuit for position control in the direction perpendicular to the moving direction of the magnetically levitated moving body is such that the cross-sectional area of the magnetic path in the magnetic gap changes due to the position control direction displacement of the position-controlled body. It may be formed in a direction perpendicular to the position control direction, and the current flowing through the electromagnets of this magnetic circuit may be controlled according to the input from the left and right position detectors.

(Effect of the Invention) As described above, according to the present invention, it is possible to configure a magnetic levitation movement path that bends at a small radius.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of the attitude control mechanism of the present invention, FIG. 2 is an explanatory view for explaining the magnetic resistance value of FIG. 1, and FIG.
FIG. 4 is an explanatory view for explaining the left and right position detector, FIG. 4 is an explanatory view of the left and right control electromagnets of FIG. 1 and other embodiments, and FIG. 5 is a sectional view of a conventional attitude control mechanism. 21 …… Magnetic guide rails, 24 …… Mobile units, 27,28 ……
Levitation electromagnet, 31, 32 ... Left and right control electromagnet

Claims (1)

[Claims] 1. A magnetic levitation moving device in which a moving body is magnetically levitated with respect to a guide rail by a magnetic levitation electromagnet and is guided in the left-right direction by a position control electromagnet in the left-right direction while traveling along the guide rail in a non-contact manner. In the above, the magnetic levitation electromagnet and the position control electromagnet are provided at the upper and lower portions facing each other across the guide rails at the left and right portions of the moving body, and the guide rails in the magnetic circuit of the left and right position control electromagnets are provided. The left and right position control electromagnets are formed on the left and right guide edges of the guide rail so that a magnetic gap between them is formed in the vertical direction and the magnetic path cross-sectional area of the magnetic gap changes depending on the lateral displacement of the moving body. An attitude control device for magnetic levitation movement, which is vertically oriented.