JP3373694B2 - Magnetic levitation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic levitation apparatus which conveys an object to be conveyed, which is made of a magnetic material such as a steel plate, by a magnetic levitation in a non-contact manner.

[0002]

2. Description of the Related Art For example, in the cold rolling process of a steel mill, when transporting steel sheets between steel sheet processing apparatuses,
A method of using a roller orbit in which a large number of rollers are arranged in the conveying direction to counteract each other is adopted. Further, in a steel plate pressing process in an automobile factory or the like, a method of transporting a steel plate to be generally pressed to a press working device by using a carriage or a crane is adopted.

However, in the method using the roller track, when the roller hits the dust, the surface of the steel plate moving on the track is apt to be scratched, and the commercial value may be significantly reduced. Therefore, the roller must be constantly maintained so that dust or the like does not adhere to the roller, which requires a great deal of labor and cost. In addition, the method using a trolley or a crane has a problem that not only scratches are likely to occur during loading and unloading of steel plates, but also much time is spent for transfer.

Therefore, various devices have recently been developed in order to solve these problems. For example, a large number of electromagnets are arranged on the orbit, and the electromagnets are excited one after another when the end of the steel plate moving along the orbit below the electromagnet is about to reach the electromagnet, and the attraction force of the electromagnet is supported by the weight of the steel plate. And to apply thrust to the steel sheet, it prevents the steel sheet from being adsorbed to the electromagnet by ejecting air from the compressed air passage provided between the electromagnet and the steel sheet to the steel sheet side, and A contact support device has been developed (Nikkei Mechanical 1989.6.12).

[0005] In addition, research on supporting a thin steel plate with four electromagnets (Proceedings of the National Conference of the Institute of Electrical Engineers of Japan, Industrial Application Division,
July 1989, p. 915) and a device for guiding a steel sheet in a non-contact manner by using a specially shaped electromagnet have been developed (Japanese Patent Laid-Open No. 2-270739).

However, these techniques are expected to be very difficult to convey a wide variety of steel plates over a long distance because of the complicated equipment and the narrow size and weight range of the steel plates that can be conveyed. To be done.

[0007]

As described above, in the case of transporting a steel sheet without damaging it, a means using mechanical contact requires a great deal of labor and time for maintenance and shock prevention measures during transport. Become. Further, in the non-contact transfer means according to the conventional technique, there are problems that the size and weight of the steel plate that can be transferred are limited, and that the device is complicated and it is difficult to carry the long distance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic levitation device that can convey a wide variety of objects to be conveyed formed of a magnetic material over a long distance in a non-contact manner and can easily construct a conveyance line. I am trying.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a magnet unit provided with an electromagnet, a mount for mounting the magnet unit, and an object to be conveyed, at least a part of which is made of a magnetic material, are supported in a non-contact manner. A magnetic support control means for controlling the attraction force of the electromagnet, an inclination means for inclining the gantry to change the inclination angle of the transported object in the transport direction, and an inclination angle control means for controlling the inclination angle. It is characterized by having. Further, according to the present invention, in order to support a magnet unit including an electromagnet, a pedestal for mounting the magnet unit, and a transported object, at least a part of which is formed of a magnetic body, in a non-contact manner, the attraction force of the electromagnet is used. Magnetic support control means for controlling the tilting angle, tilting means for changing the tilting angle of the transported object in the carrying direction, and tilting angle control means for controlling the tilting angle, the magnet unit via the tilting means. The magnet unit is vertically moved by the tilting means.

[0010]

According to the present invention, the guiding force acts on the transported body by tilting the floating transported body and the resultant force of gravity and the attraction force of the magnet unit. The guide force can be adjusted by detecting the amount or speed of movement of the transported object in the guiding direction and controlling the tilt angle of the transported object, so there is no need to install a new electromagnet for guiding, and the support mechanism is simple. Be converted.

Further, since the guided force is obtained by inclining the transported body, it is possible to obtain a guiding force having a magnitude corresponding to the mass of the transported body, and further, the width of the transported body is the magnet unit interval in the guiding direction. Even if it is wider, the guided object can be guided. Therefore, a wide variety of steel plates can be supported over a long distance in a non-contact manner, and a transport line can be easily constructed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a steel plate conveying device using a magnetic levitation device according to an embodiment of the present invention.

The steel plate transport device 12 is a transport vehicle having a track 14 laid along a predetermined path and a magnetic levitation device 10 according to the present invention.
It consists of 16. The track 14 has L-shaped track support columns 18 fixed on the upper surface of a base plate 20 and has track support parts 22 installed on the left and right sides of the conveyance path, and each track support part 22 has an L-shaped cross section. It is formed by fixing the rail 24. The track support column 18 is formed of an insulating member, and the guide rails 24 are formed of a conductive member. The left and right guide rails 24 are connected to a power source (not shown) by a predetermined method.

The transport vehicle 16 is constructed by attaching drive units 26 to the upper four corners of the magnetic levitation device 10, and is arranged so that it can travel along the track 14. The drive unit 26 includes a wheel 28, a motor 30 that drives the wheel 28, and a travel control device 32 that controls the motor 30 in accordance with a wireless command from the outside to cause the transport vehicle 16 to travel, stop, and reverse.

The wheel 28 is a conductive member, and by contacting the left and right guide rails 24, the magnetic levitation device 10 and the drive unit.
It supplies the necessary power to 26. The magnetic levitation device 10 is a square base 34, a tilting means 36 attached to the front and rear flat plate-shaped members of the base 34, and a flat mount 38 joined to the tilting means 36 via a universal joint 37, Magnet units 40 are arranged on the bottom surface of the gantry 38, three in each of the left and right rows, for a total of six
A gap sensor 44 arranged on both sides of each magnet unit 40 for measuring the gap length between the magnet unit 40 and the steel plate 42 as the transported object in a non-contact manner. The feed monitor 46 for measuring the amount of movement of the facing portions in the left-right direction in a non-contact manner, and the amount of movement of the facing portions of the steel plate 42 in the front-back direction located in the center of the left and right ends of the lower surface of the frame 38 is measured in a non-contact manner. Feed monitor 48, eight steel bars 42, eight guide bars 50 arranged so as to sandwich the four corners of the gantry 38 in order to prevent the steel plate 42 from falling out of the non-contact supportable range created by the magnet unit 40, and the attraction force of the magnet unit 40 is controlled. Support means for supporting the steel plate 42 in a non-contact manner
52, a tilt angle control means 54 for guiding the steel plate 42 by controlling the tilt angle of the mount 38 by the tilt means 36 in order to prevent the steel plate 42 from deviating from the non-contact supportable range created by the magnet unit 40. There is.

Here, the traveling control device 32, the magnetic support control means 52, and the inclination angle control means 54 are provided with a base 34 as shown in the drawing.
It is fixed on the left and right members. Further, the universal joint 37 has a structure having appropriate flexibility so as to absorb a mechanical dimensional error.

The feed monitor 46 and the feed monitor
When the steel plate 42 is apart from the predetermined position, the reference numeral 48 outputs zero. Magnet unit
As shown in FIG. 2, the 40 is configured by sandwiching a permanent magnet 56 between two electromagnets 62 composed of a coil 58 and an iron core 60. The two coils 58 have their magnetic fluxes mutually generated by the same exciting current. They are connected in series to strengthen each other.

As shown in FIG. 3, the traveling control device 32 introduces electric power from a power source (not shown) from the guide rails 24 via the left and right wheels 28 to generate a predetermined constant voltage three-phase alternating current. Constant voltage source 64 for driving, constant voltage from running constant voltage source 64 is introduced, and frequency command value ω from excitation frequency calculator 66
Four inverters 68 that excite each motor 30 based on
Four speed detectors 70 for calculating the traveling speed of the transport vehicle 16 from the number of rotations of each wheel 28 and the transport vehicle by wireless from the outside.
Four frequency commands to excite each motor 30 from the speed command value generator 72 that outputs the 16 target travel speeds, the speed detector 70, and the speed command value generator 72 so that the transport vehicle 16 travels at the target travel speed. A traveling control unit 74 including an excitation frequency calculator 66 for calculating the value ω, and guide rails via the left and right wheels 28.
The power supply voltage is introduced from 24, and a predetermined constant voltage is applied to the travel control unit 74.
It is composed of a constant voltage source for control 76 which is generated and supplied to.

In the control block diagrams shown in FIG. 3 and subsequent figures, the bar lines indicate the power path and the arrows indicate the signal path. Inclination means
The reference numeral 36 designates four vertically expandable actuators 78 which are attached to the front and rear flat plate-shaped members of the U-shaped base 34 at predetermined intervals and are attached to the left and right sides of each actuator 78 at predetermined intervals. Eight linear guides 80 that are arranged and attached through the front and rear plate-shaped members of the base 34, and eight rods 82 that pass through each linear guide 80 and are movable only in the vertical direction
Each actuator 78 and each bar 82
Is connected to a flat frame 38 via a universal joint 37. Further, the amount of expansion and contraction of the actuator 78 is controlled by the inclination angle control means 54, which allows the inclination means 36
Can support the gantry 38 at a predetermined inclination and a predetermined height. Here, each linear guide 80 also serves as a moving distance measuring device for the rod 82.

Next, referring to FIG. 4, the magnetic support control means 52
Will be explained. The magnetic support control means 52 controls each magnet unit 40.
12 gap sensors that are close to the left and right of the robot and measure the levitation gap length between each magnet unit 40 and the steel plate 42.
44 (gap sensor 44a-1, 44a-2, 44b-1, 44b-2, ..., 44f-
1,44f-2), a levitation sensor section 86, and a levitation sensor section 86 composed of current detectors 84a, 84b, 84c, 84d, 84e, 84f for measuring the exciting current flowing in each coil of the electromagnet 62. Output signals za-1, za-2,…, zf-1, zf-2, ia, ib,…, if are input, and the excitation voltage ea, eb for each magnet unit 40 required to levitate the steel plate 42. , ..., ef for calculating the levitation unit 88, and the left and right wheels 28 to introduce electric power from a power source (not shown) from the guide rail 24 to generate a predetermined constant voltage levitation constant voltage source 9
0, power amplifiers 92a, 92b, ..., 92f, which are connected to the levitation constant voltage source 90 and excite the coil 58 of each magnet unit 40 based on the outputs ea, eb, ..., Ef of the levitation calculator 88, not shown Power is supplied from the power supply via the guide rail 24 and wheels 28,
Gap sensor 44 and levitation calculator with a predetermined constant voltage
It is composed of a control constant voltage source 93 that supplies power to 88.

The levitation calculator 88 is, for example, a levitation gap length setter 94, a current setter 96, and a gap sensor located on the left and right of each magnet unit 40, which outputs a predetermined set value set by the main computer wirelessly. The average flying height of the steel plate 42 and the magnet unit 40 is za, z
The average value calculation circuit 98 that outputs b, ..., Zf, and the flying gap length set value are output values za, zb, respectively of the average value calculation circuit 98.
…, Subtractors 100a, 100b,…, 100f for subtracting from zf,
Subtractors 102a, 102b, ..., 102f for subtracting the set current value from the current detectors 84a, 84b, ..., 84f, output values za-1, za-2, ..., zf-1, zf of the gap sensor 44 -2 to all magnet units 40
A steel plate detection circuit 104 for determining whether or not the steel plate 42 exists within a range in which the magnet unit 40 can float at a lower position and starts this determination based on a transfer start command from a main computer (not shown), a subtracter 100a, 100
From the output value of b, ..., 100f, the deviation Δz of the barycentric coordinates of the steel plate 42 from the predetermined position, the pitch angle Δξ of the steel plate 42, the roll angle Δθ of the steel plate 42, and the twist of the steel plate 42 below the four corners of the frame 38,
Floating gap length deviation coordinate conversion circuit for obtaining three torsional mode deviations related to the torsion of the steel plate 42 at the front and rear ends of the gantry 38 and the center position of the gantry 38 and the deflection of the steel plate 42 at the front and rear ends of the gantry 38 and the center position of the gantry 38 106, coil exciting current Δiz contributing to vertical movement of the center of gravity of the steel plate 42, coil exciting current Δiξ, Δ contributing to pitching and rolling of the steel plate 42
iθ contributes to the twist of the steel plate 42 below the four corners of the gantry 38, the twist of the steel plate 42 at the front and rear ends of the gantry 38 and the center of the gantry 38, and the bending of the steel plate 42 at the front and rear ends of the gantry 38 and below the center of the gantry 38 3 Contributes to the vertical movement of the center of gravity of the steel plate 42 by using the outputs Δz and Δiz of the exciting current deviation coordinate conversion circuit 108, the levitation gap length deviation coordinate conversion circuit 106 and the exciting current deviation coordinate conversion circuit 108 for obtaining the two torsion mode exciting currents. Vertical movement mode control voltage calculation circuit 110 and floating gap length deviation coordinate conversion circuit 106 for calculating coil excitation voltage ez
And the outputs of the exciting current deviation coordinate conversion circuit 108 Δξ, Δi
Pitch mode control voltage calculation circuit 11 for calculating the coil excitation voltage e ξ that contributes to the pitching of the steel plate 42 by inputting ξ
2 and the roll gap control voltage calculation circuit 114 that calculates the coil excitation voltage eθ that contributes to the rolling of the steel plate 42 by using the outputs Δθ and Δiθ of the floating gap length deviation coordinate conversion circuit 106 and the excitation current deviation coordinate conversion circuit 18 as inputs. The output ez of the control voltage calculation circuit 118 and the control voltage calculation circuit 118, which are composed of a twist mode control voltage calculation circuit 116 that calculates three excitation voltages related to each twist mode by inputting one twist mode deviation and the twist mode excitation current , Eξ, eθ and the respective excitation voltages for the three twist modes and the detection signal TF of the steel plate detection circuit 104 as input, the excitation voltage for exciting the respective magnet units 40 when the steel plate 42 exists below the gantry 38.
It is composed of a control voltage coordinate reverse conversion circuit 120 for calculating ea, eb, ..., Ef.

In the control voltage coordinate reverse conversion circuit 120,
When the steel plate detection signal TF changes from none to yes, the six zero outputs are switched to ea, eb, ..., Ef after a predetermined time t1. Next, the tilt angle control means 54 will be described with reference to FIG.

The inclination angle control means 54 includes four linear guides 80a, 80b, 80c and 80d for outputting the moving distances zbsa to zbsd of the respective linear guides 80, which are height information of the gantry 38, and right and left portions of the steel plate 42. Feed monitors 48a and 48b that output the front-rear movement amounts xbsa and xbsb, and the left-right movement amount yb of the front and rear portions of the steel plate 42.
A guiding sensor section 122 including a feed monitor 46a, 46b for outputting sa, ybsb, a presence / absence detection signal TF of the steel plate 42 output from the magnetic support control means 52, a floating gap length deviation Δz of the center of gravity of the steel plate 42, and for guiding Output signals zbsa to zbsd, xbsa, xbsb, ybsa, ybsb of the sensor unit 122.
Is introduced to control the expansion and contraction of the four actuators 78 to guide the steel plate 42 in the front-back, left-right direction.
To idd, a guidance computing unit 124, a guidance constant voltage source 125 that generates a predetermined constant voltage, and a guidance constant voltage source 125. Each actuator is based on the outputs ida to idd of the guidance computing unit 124. Current drivers 126a to 126d for driving the motor of 78 and expanding and contracting the actuator 78, power is supplied from a power source (not shown) via the guide rail 24 and the wheels 28, and a predetermined constant voltage is supplied to the guiding sensor unit 122 and the guiding calculation. It is composed of a control constant voltage source 127 that supplies power to the unit 124.

The guide calculator 124 selectively selects a plurality of set values relating to the height of the center of gravity of the gantry 38 wirelessly set by a main computer (not shown) based on the steel plate detection signal TF from the magnetic support control means 52. The platform height setting device 128 that outputs the set position, the front and rear position setting device 130 that outputs the set value related to the front and rear position of the steel plate 42 wirelessly set by a main computer (not shown), and the left and right that outputs the set value related to the left and right position of the steel plate 42. Position setter 132, gantry height setter 12
The output value of 8 is the output value of each linear guide 80 zbsa to zbsd
13 for subtracting the output values of the front and rear position setter 130 from the output values xbsa, xbsb of each feed monitor 48, and the output value of the left and right position setter 132 for each feed monitor 46. Of the subtractors 138 and 134 for subtracting from the output values ybsa and ybsb of
A frame height coordinate calculation circuit 140 for calculating a deviation Δzbs from the set value of the height of the center of gravity of the frame 38, a pitch angle Δξbs and a roll angle Δθbs of the frame 38 by inputting Δzbsd.
The outputs Δxbsa and Δxbsb of the subtractor 136 are used as inputs, and the front-back inclination angle calculation circuit 142 for calculating the pitch angle Δξbc of the pedestal 38 for guiding the steel plate 42 in the front-rear direction based on these values, and the output of the subtracter 138. With the input of Δybsa and Δybsb, the horizontal inclination angle calculation circuit 144 for calculating the roll angle −Δθbc of the gantry 38 for guiding the steel plate 42 in the horizontal direction based on these values, and the steel plate detection signal TF When the output is 0, 0 and TF changes from none to yes, a predetermined time t
2 Guidance control circuit 14 that outputs Δξbc and -Δθbc later
6, using the deviation Δz from the magnetic support control means 52 and the steel plate detection signal TF as input, the steel plate is placed below all the magnet units 40.
The output Δ of the switch 148, which outputs Δz when 42 is floating, and 0 when it is not floating, and the platform height coordinate calculation circuit 140
zbs and adder 150 for adding the output of switch 148, Δ
A subtracter 152 for subtracting the output Δξbc of the guidance control circuit 146 from ξbs, and an output of the guidance control circuit 146 from Δθbs.
Average height mode excitation current calculation circuit for calculating the motor drive current izbs of the actuator 78 related to the height of the center of gravity of the steel plate 42 from the outputs of the subtracter 154 and the adder 150 for subtracting Δθbc
156, a forward / backward tilt mode excitation current calculation circuit 158 for calculating a motor drive current i ξbs of the actuator 78 for pitching the pedestal 38 from the output of the subtractor 152, and a subtractor 154
From the output of
A right / left tilt mode exciting current calculating circuit 160 for calculating the motor drive current iθbs of
The pedestal height control current coordinate reverse conversion circuit 164 outputs the control current values ida to idd for controlling the expansion and contraction of the four actuators 78 by using the outputs izbs, iξbs and iθbs of the exciting current calculation circuit 162 as inputs.

In the gantry height setting device 128, when the steel plate detection signal TF changes from none to yes, a set value is selected after a predetermined time t2, and the switching device 148 changes the steel plate detection signal TF from none to yes. Changes to 0 after a predetermined time t3
Is switched to.

Next, the operation of the magnetic levitation apparatus according to this embodiment having the above-mentioned structure will be described. First, a case in which the steel plates 42 placed at a predetermined point on the track 14 by the plurality of transport vehicles 16 are transported to another predetermined point will be described with reference to FIG.

In FIG. 6, reference numeral 166 is a pedestal on which the steel plate 42 is placed. First, the process leading to FIG. 6A will be described. When the traveling speed is commanded by the main computer, the transport vehicle
In 16, in the traveling control device 32, the command speed is set in the speed command value generator 72, the actual vehicle speed of the speed detector 70 and the speed command value are compared, and the excitation frequency for rotating the motor 30 so that they match each other. ω is output from the excitation frequency calculator 66, and the transport vehicle 16 quickly travels at the command speed.

At this time, since the transport vehicle 16 is not transporting the steel plate 42, the transport start command is not issued from the main computer. Therefore, in the magnetic support control means 52, the steel plate detection circuit 104 in which the outputs of all the gap sensors 44 are introduced.
At, a TF signal indicating that there is no steel plate is output, and this detection signal TF is transmitted to the control voltage coordinate reverse conversion circuit 120, and the control voltage coordinate reverse conversion circuit 120 outputs zero. Therefore, the coil 58 is not excited.

Further, the detection signal TF is also transmitted to the tilt angle control means 54, and in the gantry height setting device 128, a predetermined height h1 at which the magnet unit 40 does not attract the steel plate 42 due to the attractive force of the permanent magnet 56. In addition to being output, the guidance control circuit 146 outputs 0, 0 instead of Δξbc, −Δθbc, and guidance control is not performed.

Further, in the feed monitors 46a, 46b and the feed monitors 48a, 48b, since the steel plate 42 does not exist, the front and rear and left and right movement amounts xbsa, xbsb, ybsa, ybsb become zero.

On the other hand, when the outputs zbsa to zbsd of the linear guides 80a, 80b, 80c and 80d are different from the output value h1 of the gantry height setter 128, the outputs Δzbsa to Δzbsd of the subtractor 134.
Based on the above, the pedestal height coordinate calculation circuit 140 calculates Δzbs, Δξb
s, Δθbs are calculated, and three zero outputs from the switch 148 and the guide control circuit 146 are added to the adder 150,
Δzbs, Δξbs, Δθ in the subtracters 152 and 154
It is added to or subtracted from bs and introduced into the control voltage calculation circuit 118.

In the control voltage calculation circuit 118, the deviation Δzbs
A mode related to the height of the center of gravity of the gantry 38 that converges to zero,
Excitation currents iz in the mode relating to the tilt in the front-rear direction that converges the deviation Δξbs to zero and in the mode relating to the tilt in the left-right direction that converges the deviation Δθbs to zero
bs, iξbs and iθbs are calculated. Outputs izbs, iξbs and iθbs of the control voltage calculation circuit 118
Are converted into motor drive current values ida to idd in the gantry height control current coordinate reverse conversion circuit 164, and the current driver
Each actuator 78 is driven via 126.

In this way, the expansion and contraction of the actuator 78 is controlled, and the gantry 38 is maintained horizontally at the height of the gantry height set value h1. When the transport vehicle 16 eventually reaches above the pedestal 166, the traveling speed command value is set to zero, and
16 will stop immediately. At this time, as shown in FIG. 6A, the steel plate 42 is placed on the pedestal 166.

When the transport vehicle 16 is in the state shown in FIG. 6 (a), a transport start command is transmitted from a main computer (not shown) to the steel plate detection circuit 104 to determine the presence / absence of a steel plate, and the steel plate detection circuit 104 detects the steel plate. When the predetermined height h2 that is detected to be present is output to the gantry height setter 128, the above-described control operation occurs in the tilt angle control means 54,
The actuator 78 extends and the gantry 38 reaches a predetermined set height h2 as shown in FIG. 6 (b). Then, in the magnetic support control means 52, since the output values of all the gap sensors 44 are smaller than the predetermined position, the steel plate detection circuit 104 detects that there is a steel plate. And the height of the gantry 38 is equal to the magnet unit 40.
The fact that the steel plate 42 has reached the levitable range is transmitted to the control voltage coordinate reverse conversion circuit 120 by the detection signal TF, and after t1 hours from this time, that is, after the height control of the gantry 38 is finished, Such ascent control is started.

That is, the gap sensors 44a-1, 44a-2,
..., 44f-1, 44f-2 output values za-1, za-2, ..., zf-1, zf-2 are average values of those positioned at both ends of each magnet unit 40 by the average value calculation circuit 98. It is output as za ~ zf.

Za to zf are subtracted from the output of the levitation gap length setter 94 by the subtracters 100a to 100f, and the subtraction result is introduced to the levitation gap length deviation coordinate conversion circuit 106 to determine the barycentric coordinates of the steel plate 42 from a predetermined position. Deviation Δz, pitch angle deviation Δξ,
Regarding the roll angle Δθ, the twist of the steel plate 42 below the four corners of the gantry 38, the twist of the steel plate 42 at the front and rear ends of the gantry 38 and the central position of the gantry 38, and the bending of the steel plate 42 at the front and rear ends of the gantry 38 and the central position of the gantry 38 3 The two torsion mode deviations are calculated, and the excitation current measurement values ia to if of the electromagnet 62 detected by the current detectors 84a to 84f are subtracted from the zero output of the current setter 96 by the subtractors 102a to 102f, and the subtraction result is excited. A coil exciting current Δiz that is introduced into the current deviation coordinate conversion circuit 108 and contributes to the vertical movement of the center of gravity of the steel plate 42, a coil exciting current Δiξ that contributes to pitching, a coil exciting current Δiθ that contributes to rolling, and a steel plate below the four corners of the gantry 38. 3 which contribute to the twist of 42, the twist of the steel plate 42 at the front and rear ends of the gantry 38 and the central position of the gantry 38, and the bending of the steel plate 42 at the front and rear ends of the gantry 38 and the central position of the gantry 38 Torsional mode excitation current is calculated.

Of the outputs of the floating gap length deviation coordinate conversion circuit 106 and the exciting current deviation coordinate conversion circuit 108, Δz,
Δiz, Δξ, Δiξ and Δθ, Δiθ are introduced into the vertical movement mode control voltage calculation circuit 110, the pitch mode control voltage calculation circuit 112 and the roll mode control voltage calculation circuit 114, respectively, and contribute to the vertical movement of the center of gravity of the steel plate 42. The coil exciting voltage ez, the coil exciting voltage e ξ contributing to the pitching, and the coil exciting voltage e θ contributing to the rolling are calculated. When calculating ez, eξ and eθ, Δiz and Δiξ are calculated in the steady floating state of the steel plate 42.
Zero power control is performed so that and Δiθ converge to zero.

At this time, the corresponding pairs of the three torsion mode deviations and the three torsion mode exciting currents are introduced into the three torsion mode control voltage arithmetic circuits 116, and
38 Twisting of the steel plate 42 below the four corners
38 Contributes to the twist of the steel plate 42 below the central position and the bending of the steel plate 42 at the front and rear ends of the gantry 38 and the gantry 38 central position 3
The two torsion mode excitation voltages are calculated.

Also in these calculations, zero power control is performed in which the three torsion mode exciting currents converge to zero when the steel plate 42 is in a normal floating state. By this levitation control, so-called zero power control (detailed in Japanese Patent Application No. 4-351167) in which ia to if converge to zero in the steady floating state of the steel plate 42 is achieved as a whole, and the steel plate 42 is Stable surface. At this time, the flying gap length deviation Δz converges to a value according to the weight of the steel plate 42.

On the other hand, the fact that the height of the gantry 38 has reached the range in which the magnet unit 40 can float the steel plate 42 indicates that the detection signal TF
Is also transmitted to the tilt angle control means 54. In the tilt angle control means 54, the detection signal TF is introduced to the gantry height setting device 128, the guide control circuit 146 and the switching device 148.

The gantry height setter 128 selects a predetermined set value h3 when the steel plate 42 floats, that is, when the steel plate 42 is supported in a non-contact manner after t2 time when the detection signal TF changes from nothing to present. Then, the gantry 38 rises. When the ascending of the gantry 38 is completed, that is, after t3 time when the detection signal TF changes from nothing to yes, Δz is selected in the switch 148,
The flying gap length deviation when the steel plate 42 is in a steady floating state is introduced into the adder 150.

Therefore, in the tilt angle control means 54,
The height of the pedestal 38 is controlled so as to cancel the steady deviation Δz, and the steel plate 42 always floats at a predetermined height as shown in FIG. 6C regardless of its weight.

Further, when the detection signal TF changes from none to yes
After 2 hours, guidance control is started. That is, FIG.
When the gantry 38 descends from the state of (a), the steel plates 42 are removed from the feed monitors 46a and 46b and the feed monitors 48a and 48b.
Since the distance to is within a predetermined range, the amounts of movement xbsa, xbsb, ybsa, ybsb of the front and rear and right and left of the steel plate 42 are output, and the output of the guide control circuit 146 after t2 time when the detection signal TF changes from none to yes. From 0,0 to Δξbc, −Δθ
Switch to bc. At this point, xbsa, xbsb, yb
The sa and ybsb are compared with the zero outputs of the front and rear position setter 130 and the left and right position setter 132 in the subtractor 136 and the subtractor 138, and the outputs Δxbs of the subtractor 136 and the subtractor 138 are compared.
a, .DELTA.xbsb, .DELTA.ybsa, .DELTA.ybsb are introduced into the front-rear tilt angle calculation circuit 142 and the left-right tilt angle calculation circuit 144.

In the longitudinal inclination angle calculation circuit 142, (Δ
xbsa + Δxbsb) / 2 for canceling pitch angle Δξ
In addition to the calculation of bc, the horizontal tilt angle calculation circuit 144 calculates the roll angle −Δθbc for canceling (Δybsa + Δybsb) / 2. The pitch angle Δξbc is the output Δ of the gantry height coordinate calculation circuit 140 in the subtractor 152.
It is subtracted from ξbs, and the subtraction result is introduced to the front-back inclination mode exciting current operation circuit 158. Also, the roll angle −Δθb
In the subtractor 154, c is subtracted from the output Δθbs of the gantry height coordinate calculation circuit 140, and the subtraction result is introduced to the horizontal tilt mode excitation current calculation circuit 160.

In the forward / backward tilt mode excitation current calculation circuit 158, since the excitation current iξbs for which (Δξbs-Δξbc) should be zero is calculated, the expansion / contraction of the actuator 78 is controlled so that the gantry 38 moves in the forward / backward direction of the steel plate 42. Tilt to cancel the gap.

Similarly, in the left / right tilt angle calculation circuit 144, the exciting current i for which (Δθbs + Δθbc) should be zero.
Since θbs is calculated, the expansion and contraction of the actuator 78 is controlled, and the gantry 38 tilts so as to cancel the lateral displacement of the steel plate 42.

By this guide control, the steel plate 42 is always mounted on the mount 38.
Be maintained in a state of facing. When the guided vehicle 16 is in the state shown in FIG. 6 (c), when the commanded traveling speed is gradually increased by the main computer, the guided vehicle 16 accelerates. At the time of acceleration, the steel plate 42 moves to the rear of the gantry 38, but the guide control described above causes the gantry 38 to incline and the steel plate 42 to follow the gantry 38 as shown in FIG. 6 (d). When the transport vehicle 16 is traveling at a constant command speed at a constant speed, as shown in FIG.
Is almost horizontal.

When the transport vehicle 16 approaches the destination point and the instruction traveling speed is gradually reduced, the transport vehicle 16 decelerates. At the time of deceleration, the steel plate 42 moves to the front of the gantry 38, but by the guide control described above, the gantry 38 is inclined and the steel plate 42 follows the gantry 38 as shown in FIG. 6 (f).

In this way, when the vehicle arrives at the destination and the commanded speed becomes zero, the carrier vehicle 16 stops as shown in FIG. 6 (g). During this time, a lateral external force is applied to the floating steel plate 42, and in the case of Fig. 7 (a) in which the steel plate 42 is biased to the left, as shown in Fig. 7 (b), it is biased to the right in Fig. 7 (d). In this case, as shown in FIG. 7 (d), the pedestal 38 is inclined so that the guide control for returning the steel plate 42 to its original position is performed, and the state where the steel plate 42 and the pedestal 38 face each other is maintained.

The transport vehicle 166 stops, and the steel plate is guided by the guide control.
When the main computer causes the gantry height setter 128 to output a predetermined gantry height h4 when 42 is stationary,
38 descends and the steel plate 42 lands on the pedestal 166. At this time, when the transport end signal is transmitted from the main computer, the steel plate detection circuit 104 outputs a TF signal indicating that the steel plate 42 does not exist. Then, the control voltage coordinate reverse conversion circuit 120 and the guide control circuit 146 output zero, the levitation control and the guide control are stopped, and the gantry height setter 128 outputs a predetermined gantry height h1. As shown in h), the pedestal 38 rises with the steel plate 42 left on the pedestal 166, the pedestal height reaches h1, and the conveyance is completed in the state of FIG. 6 (i).

In the present embodiment, the gap sensors 44 are arranged at both ends of the magnet unit 40, which allows the floating gap between the magnet unit 40 and the steel plate 42 to be bent even if the steel plate to be conveyed has a deflection. It becomes possible to detect the length more accurately.

In the levitation control, the motion of the steel plate 42 is decomposed into motion coordinate systems and the levitation control is performed for each mode. Therefore, the levitation control system can be designed for each mode. Robust levitation control can be performed against changes in the weight, material, and thickness of the steel sheet.

Further, although the zero power control is used for the levitation control, if the steel plate 42 is supported in a non-contact manner by such zero power control, the levitation gap length of the magnet unit 40 whose load is increased due to the deviation of the steel plate 42 decreases. With respect to the positional deviation of the steel plate 42 in the front-rear direction and the left-right direction, the steel plate is inclined in the direction in which it is returned to the original position, and the effect of the guide control is further provided. That is, the magnetic support control means also serves as the tilt angle control means.

In the above embodiment, the magnetic levitation device is used.
Although 10 is incorporated in the transport vehicle 16, this does not limit the presence or absence of the transport means for the steel plate and the inclination means. For example, as shown in FIG.
Joint mechanism that allows bending of 2 degrees of freedom at the lower end of the hand 170
The 172 may be attached and used as the tilting means of the magnetic levitation device 10. The SCARA robot 168 has a degree of freedom about the axis shown in FIG. 8 and is configured such that the actuator 174 moves the hand portion 170 up and down.

With this structure, the inclination of the pedestal 38 is controlled by the bending motion of the joint mechanism 170 and the vertical movement of the actuator 174 according to the movement of the hand portion 170, so that the steel plate 42 is always supported by the pedestal 38. Are supported in a non-contact manner in a state of facing each other.

Of course, it goes without saying that the present invention can be widely used for carrying and carrying purposes other than the above-mentioned SCARA robot. Further, in the above-described embodiment, the magnet unit is attached to the flat plate-shaped mount 38, and the steel plate is tilted by tilting the mount 38 to achieve the guide control, but this is the method of mounting the magnetic support unit. Is not intended to be limited in any way.

For example, as shown in FIG. 9, in the magnetic levitation device 10 of FIG.
A strip member 176 is fixed to the lower end of a bar member 82 that penetrates the linear guides 80 at the left and right ends thereof, and the magnet unit 40 and the gap sensor 44 are arranged on the lower surface of the strip member 176 to provide a magnetic levitation device.
178 may be configured. In this case, the base 34 can be regarded as a mount for attaching the magnet unit 40. Further, the feed monitors 46 and 48 attached to the lower surface of the strip-shaped member 180 are fixed to the base 34 via a pedestal 182.

In such a structure, the height of each magnet unit is changed to incline the steel sheet for guiding control, and magnetically levitated of the transported object such as the steel sheet 42 'having a large distortion. Becomes

Further, in the above-mentioned embodiment, the steel plate is supported by six magnet units in a non-contact manner, but this does not limit the number of magnet units. For example, as shown in FIG. 10, 12 magnet units may be used without any problem. By using a large number of magnet units in this way, it is possible to cope with an increase in the weight of the transported object, and it is possible to reduce the supporting weight and the magnetic flux per magnet unit.
Even if the transported object is a thin steel plate, saturation of magnetic flux can be avoided,
Stable non-contact support becomes possible.

In addition, in this embodiment, the U-shaped magnet unit is provided with a permanent magnet, but this does not limit the shape or configuration of the magnet unit. For example, E
There is no problem even if the magnet unit is configured by electromagnets having various shapes such as a letter shape or a cylindrical shape.

In the present embodiment, the transported object is a flat steel plate, but this does not limit the material or shape of the transported object. Any shape may be used as long as the transported body is made of a magnetic material or a ferromagnetic material.

Further, in the above-mentioned embodiment, the control device and its operation are expressed in an analog manner, but the control system is not limited to such a control system, and a digital system may be adopted. As described above, it goes without saying that the present invention can be variously modified and implemented without departing from the scope of the invention.

[0063]

As described above, according to the magnetic levitation device of the present invention, the guiding force is exerted on the transported object by the resultant force of gravity and the attractive force of the magnet unit by tilting the suspended transported object. To work. The guide force can be adjusted by detecting the amount or speed of movement of the conveyed object in the guiding direction and controlling the inclination angle of the conveyed object.Therefore, it is not necessary to install a new electromagnet for guiding, and the support mechanism is simplified. To be done.

Further, since the guided force is tilted to obtain the guiding force, it is possible to obtain a guiding force having a magnitude corresponding to the mass of the transported object, and further, the width of the transported object is the magnet unit interval in the guiding direction. Even if it is wider, the guided object can be guided. For this reason, a wide variety of magnetic bodies can be supported over a long distance in a non-contact manner, and a transport line can be easily constructed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a magnetic levitation transport device of the present invention.

FIG. 2 is a perspective view showing a carrier vehicle used in the carrier device.

FIG. 3 is a block configuration diagram of a travel control device used in the conveyance device.

FIG. 4 is a block configuration diagram of a magnetic support control device used in the transport device.

FIG. 5 is a block configuration diagram of a tilt angle control device used in the conveyance device.

FIG. 6 is an operation explanatory view for explaining a carrying operation by the carrying device.

FIG. 7 is an operation explanatory view for explaining another carrying operation by the carrying device.

FIG. 8 is a perspective view showing a SCARA robot to which the magnetic levitation device of the present invention is applied.

FIG. 9 is a perspective view showing another embodiment of the magnetic levitation device of the present invention.

FIG. 10 is a perspective view showing another embodiment of the magnetic levitation device of the present invention.

[Explanation of symbols]

10, 178 ... Magnetic levitation device 12 ... Steel plate transport device 14 ... Track 16 ... Transport vehicle 24 ... Guide rail 26 ... Drive part 28 ... Wheel 30 ... Motor 32 ... Travel control device 34 ... Base 36 ... Inclination means 37 ... Universal joint 38 ... Frame 40, 40a, 40b, 40c, 40d, 40e, 40f ... Magnet unit 42, 42 '... Steel plate 44, 44a-1, 44a-2, 44b-1, 44b-2, 44c-1, 44c-2, 44d -1,44d-2,44e-1,44e-2,44f-1,44f-2 ... Gap sensor 46, 46a, 46b, 48, 48a, 48b ... Feed monitor 52 ... Magnetic support control means 54 ... Tilt angle control Means 56 ... Permanent magnet 58 ... Coil 60 ... Iron core 62 ... Electromagnet 66 ... Excitation frequency calculator 68 ... Inverter 70 ... Speed detector 74 ... Travel controller 78 ... Actuator 80 ... Linear guide 82 ... Bar 84 ... Current detector 86 ... Levitation sensor section 88 ... Levitation calculation section 92 ... Power amplifier 122 ... Guidance sensor section 124 ... Guidance computation section 126 ... Current driver 146 ... Guidance control circuit 162 ... Excitation current computation circuit 164 ... Frame height control current Coordinate reverse transformation circuit

Claims (4)

(57) [Claims] 1. A magnet unit provided with an electromagnet, a mount for mounting the magnet unit, and a non-contact support for an object to be transported, at least a part of which is made of a magnetic material, for attracting force of the electromagnet. A magnetic support control means for controlling, an inclining means for inclining the gantry in order to change an inclining angle of the transferred object in the conveying direction, and an inclining angle controlling means for controlling the inclining angle are provided. Levitation device. 2. A magnet unit provided with an electromagnet, a mount for mounting the magnet unit, and a non-contact support for an object to be transported, at least a part of which is made of a magnetic material, for attracting force of the electromagnet. The magnetic unit includes a magnetic support control unit for controlling, a tilting unit for changing a tilt angle of the transported object in a transport direction, and a tilt angle control unit for controlling the tilt angle, and the magnet unit is provided via the tilting unit. A magnetic levitation device mounted on the gantry, wherein the magnet unit is moved in the vertical direction by the tilting means. 3. The magnet unit has a permanent magnet, and shares a magnetic path formed by the electromagnet and a magnetic path formed by the permanent magnet in an air gap between the electromagnet and the transported object. The magnetic levitation device according to claim 1, wherein the magnetic levitation device is a magnetic levitation device. 4. The magnetic support control means has a zero power control function of converging the exciting current of the electromagnet to zero when the transported body is stably floating regardless of the weight of the transported body. The magnetic levitation device according to claim 3, characterized in that it has.