Control device

Abstract

A control device (40) controls a permanent electromagnet (10) having a plurality of first permanent magnets (10a) and a plurality of second permanent magnets (10b) and a coil (10c). The electromagnet (10) can switch, by applying a voltage to the coil, between an adsorption state in which a magnetic material (W) can be attracted and a release state in which the adsorption state is released. The control device (40) includes a grouping unit (70) that divides the plurality of second permanent magnets into a plurality of magnet groups (G), and an energization control unit (72) that sequentially performs energization control for each magnet group by applying a voltage to the coil to change a magnetization direction of the second permanent magnets to a direction corresponding to the adsorption state.

Description

Control device

[0001] The present disclosure relates to a control device.

[0002] Japanese Patent Application Laid-Open No. 2017-213650 discloses a permanent electromagnetic adsorption device. In the permanent electromagnetic adsorption device, a magnetic pole unit having alnico magnets and rare earth magnets typified by neodymium magnets is provided in a matrix arrangement. A coil is disposed outside the alnico magnet. In the alnico magnet, magnetization and demagnetization are repeated by the coil. By appropriately changing the energization state of the coil, the magnetic poles of the magnetic pole unit can be switched.

[0003] In an adsorption state in which a permanent magnet having a plurality of first permanent magnets and a plurality of second permanent magnets whose magnetization directions can be reversed has an adsorption force capable of adsorbing a magnetic material, the adsorption force may be too large.

[0004] An object of the present disclosure is to solve the above-described problems.

[0005] An aspect of the present disclosure includes a plurality of first permanent magnets and a plurality of second permanent magnets, and coils wound around the outer peripheries of the plurality of second permanent magnets. When a voltage is applied to the coils, the magnetization direction of the second permanent magnet around which the coil is wound is reversed according to the direction of the current flowing, so that an adsorption state in which a magnetic material can be adsorbed and a release state in which the adsorption state is released can be switched. A control device for controlling a permanent magnet, comprising: a grouping unit that groups the plurality of second permanent magnets into a plurality of magnet groups such that each magnet group includes at least one of the second permanent magnets; and a power supply that applies the applied voltage to the coils wound around the outer peripheries of at least one of the second permanent magnets. An energization control unit that sequentially performs energization control to set the magnetization direction of at least one of the second permanent magnets in a direction corresponding to the adsorption state for each of the magnet groups.

[0006] According to the present disclosure, the adsorption force of the permanent magnet is suppressed.

[0007] Figures 1A, 1B, and 1C illustrate an example in which a magnetic material is attracted to a permanent electromagnet and supplied to industrial equipment. Figure 2 schematically shows the configuration of a permanent electromagnet capable of attracting a magnetic material and the configuration of a control device that controls the permanent electromagnet. Figure 3 shows the state in which the permanent electromagnet has attracted a magnetic material. Figure 4 illustrates multiple magnet groups. Figure 5 illustrates the change in the attractive force of the permanent electromagnet accompanying the energization control and energization deactivation control for each magnet group. Figure 6 is a flowchart illustrating the processing procedure during energization control and energization deactivation control for each magnet group. Figures 7A and 7B illustrate the change in magnetic flux in response to the energization control of the first magnet group when the magnet group includes two second permanent magnets adjacent to each other. Figures 8A and 8B illustrate the change in magnetic flux in response to the energization control of the first magnet group when the magnet group includes two second permanent magnets that are spaced apart and not adjacent to each other. Figure 9 illustrates multiple magnet groups and second permanent magnets in a first and second part. Figure 10A shows the state in which energization control and de-energization control are performed for each magnet group of the second permanent magnet in the first part. Figure 10B shows the state in which energization control and de-energization control are performed for each magnet group of the second permanent magnet in the second part. Figure 11 is a diagram illustrating the change in the attractive force of the permanent electromagnets due to the energization control and de-energization control for each magnet group. Figure 12A shows the state in which the magnetization direction of the second permanent magnet in the first part is oriented in the direction corresponding to the attractive state. Figure 12B shows the state in which the magnetization direction of the second permanent magnet in the second part is oriented in the direction corresponding to the attractive state. Figure 13 is a diagram illustrating the change in the attractive force of the permanent electromagnets due to the energization control and de-energization control for each magnet group. Figure 14 is a diagram schematically showing the configuration of a permanent electromagnet capable of attracting magnetic materials and the configuration of a control device that controls the permanent electromagnet. Figure 15 is a diagram illustrating the change in the current flowing through the coil of the permanent electromagnet according to time. Figure 16 is a flowchart illustrating the processing procedures for energizing and de-energizing each magnet group. Figure 17 is a diagram illustrating the configuration of a permanent electromagnet. Figure 18 is a diagram illustrating the sequential energizing control for each magnet group performed on the second permanent magnets arranged in a grid.

[0008] Robots sometimes supply workpieces to industrial equipment. For example, a robot supplies a steel plate to be pressed to a press machine. When the workpiece supplied to the industrial equipment, such as a press machine, is a magnetic material like a steel plate, a permanent electromagnet may be used as the robot's end effector. The magnetic force based on the magnetic force of the permanent electromagnet causes the magnetic workpiece to be attracted to the permanent electromagnet. Figures 1A, 1B, and 1C show an example in which a magnetic material W is attracted to a permanent electromagnet 10 and supplied to industrial equipment 20.

[0009] Figure 1A shows a state in which a permanent electromagnet 10 attached to a robot 30 has attracted one magnetic material W. When the magnetic materials W are processed one by one by the industrial equipment 20, the robot 30 cannot supply two or more magnetic materials W to the industrial equipment 20 at one time. Therefore, the permanent electromagnet 10 needs to attract only one magnetic material W, and not two or more magnetic materials W. It is preferable that the attractive force of the permanent electromagnet 10 is suppressed so that only one magnetic material W is attracted to the permanent electromagnet 10, even if the magnetic material W is thin and light.

[0010] Figure 1B shows the robot 30 moving toward the industrial equipment 20 on a rail (not shown). The robot 30 moves toward the industrial equipment 20 to transport the magnetic material W. The magnetic material W moves with the robot 30 while being held in place by the permanent electromagnet 10. It is preferable to reduce the possibility of the magnetic material W detaching from the permanent electromagnet 10 due to the action of inertial force generated by the movement of the robot 30.

[0011] Figure 1C shows the state in which the robot 30 is supplying a single magnetic material W to the industrial equipment 20. When the robot 30 places the magnetic material W in a predetermined area within the industrial equipment 20, the permanent electromagnet 10 returns to a released state, meaning it is no longer in an attracted state capable of attracting the magnetic material W. As the permanent electromagnet 10 returns to the released state, the magnetic material W detaches from the permanent electromagnet 10.

[0012] Figure 2 is a schematic diagram showing the configuration of a permanent electromagnet 10 capable of attracting a magnetic material W, and the configuration of a control device 40 that controls the permanent electromagnet 10. The permanent electromagnet 10 shown in Figure 2 is in a released state, where the attraction state has been released. When the permanent electromagnet 10 has an attractive force, it can attract a magnetic material W. The permanent electromagnet 10 has a plurality of first permanent magnets 10a, a plurality of second permanent magnets 10b, a plurality of coils 10c, and a top yoke 10t.

[0013] The first permanent magnet 10a is a neodymium magnet containing, for example, neodymium in addition to iron. The second permanent magnet 10b is an alnico magnet containing, for example, aluminum, nickel, and cobalt in addition to iron. The top yoke 10t is made of ferromagnetic steel and passes through a magnetic flux B corresponding to the magnetic force generated by the permanent electromagnet 10. Of the two ends of the second permanent magnet 10b that extend along the magnetization direction of the second permanent magnet 10b, the top yoke 10t covers the end that is closer to the magnetic material W that can be attracted by the permanent electromagnet 10 when the permanent electromagnet 10 has an attractive force.

[0014] In this embodiment, a plurality of second permanent magnets 10b and a plurality of top yokes 10t, each covering a plurality of second permanent magnets 10b, are arranged in a row in one direction. In the example shown in Figure 2, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged from left to right. The magnetization directions of adjacent second permanent magnets 10b are opposite to each other. Each of the six second permanent magnets 10b is covered by each of the plurality of top yokes 10t.

[0015] Each of the multiple first permanent magnets 10a is positioned between two adjacent top yokes 10t. In this embodiment, the magnetization direction of the first permanent magnet 10a is intersecting the magnetization direction of the second permanent magnet 10b. The first permanent magnets 10a may also be positioned to surround the outer circumference of the second permanent magnet 10b. In that case, the magnetization direction of the first permanent magnet 10a is parallel to the magnetization direction of the second permanent magnet 10b.

[0016] As described above, in the six second permanent magnets 10b arranged from left to right, the magnetization directions of adjacent second permanent magnets 10b are opposite to each other. For example, the magnetic pole at the end of the second permanent magnet 10b #1 covered by the top yoke 10t is the north pole, and the magnetic pole at the opposite end of the second permanent magnet 10b #1 is the south pole. The magnetic pole at one end of the first permanent magnet 10a that abuts against the right side surface of the top yoke 10t covering the end of the second permanent magnet 10b #1 is the south pole, and the magnetic pole at the other end of the first permanent magnet 10a is the north pole.

[0017] The magnetic pole of the end of the second permanent magnet 10b#2, which is covered by the top yoke 10t that abuts the other end of the first permanent magnet 10a, is the south pole, and the magnetic pole of the opposite end of the second permanent magnet 10b#2 is the north pole. The south-magnetized end of the second permanent magnet 10b#1 and the north-magnetized end of the second permanent magnet 10b#2 are covered by a bottom yoke (not shown). The bottom yoke, like the top yoke 10t, is made of ferromagnetic steel and allows a magnetic flux B corresponding to the magnetic force generated by the permanent electromagnet 10 to pass through it.

[0018] Therefore, the magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#1 passes through the top yoke 10t covering the second permanent magnet 10b#1 and enters the south pole of the first permanent magnet 10a. The magnetic flux B entering from the south pole and exiting from the north pole of the first permanent magnet 10a passes through the top yoke 10t covering the second permanent magnet 10b#2 and enters the south pole of the second permanent magnet 10b#2. The magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#2 passes through the bottom yoke and enters the south pole of the second permanent magnet 10b#1.

[0019] In other words, the magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2 and the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#1 and 10b#2 respectively is confined within the permanent electromagnet 10.

[0020] As described above, the magnetic pole at the end of the second permanent magnet 10b#2 covered by the top yoke 10t is the south pole, and the magnetic pole at the opposite end of the second permanent magnet 10b#2 is the north pole. The magnetic pole at one end of the first permanent magnet 10a, which is in contact with the right side surface of the top yoke 10t covering the end of the second permanent magnet 10b#2, is the north pole, and the magnetic pole at the other end of the first permanent magnet 10a is the south pole.

[0021] The magnetic pole of the end of the second permanent magnet 10b#3, which is covered by the top yoke 10t that abuts the other end of the first permanent magnet 10a, is the north pole, and the magnetic pole of the opposite end of the second permanent magnet 10b#3 is the south pole. The south-pole magnetized end of the second permanent magnet 10b#3 is covered by a bottom yoke (not shown), similar to the north-pole magnetized end of the second permanent magnet 10b#2.

[0022] Therefore, the magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#3 passes through the top yoke 10t covering the second permanent magnet 10b#3 and enters the south pole of the first permanent magnet 10a. The magnetic flux B entering from the south pole and exiting from the north pole of the first permanent magnet 10a passes through the top yoke 10t covering the second permanent magnet 10b#2 and enters the south pole of the second permanent magnet 10b#2. The magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#2 passes through the bottom yoke and enters the south pole of the second permanent magnet 10b#3.

[0023] In other words, the magnetic flux B passing through the first permanent magnet 10a between the second permanent magnets 10b#2 and 10b#3 and the top yoke 10t covering them is confined within the permanent electromagnet 10.

[0024] Similarly, the magnetic flux B passing through the first permanent magnet 10a between the second permanent magnets 10b#3 and 10b#4 and the top yoke 10t covering them is confined within the permanent electromagnet 10. The magnetic flux B passing through the first permanent magnet 10a between the second permanent magnets 10b#4 and 10b#5 and the top yoke 10t covering them is confined within the permanent electromagnet 10. The magnetic flux B passing through the first permanent magnet 10a between the second permanent magnets 10b#5 and 10b#6 and the top yoke 10t covering them is confined within the permanent electromagnet 10.

[0025] In other words, all of the magnetic flux B shown in Figure 2 is confined within the permanent electromagnet 10. In this case, none of the magnetic flux B passes through the magnetic material W. Thus, when the magnetic circuits formed by the magnetic flux B are all closed and formed between the first permanent magnet 10a and the second permanent magnet 10b, the permanent electromagnet 10 does not possess any attractive force. Therefore, the permanent electromagnet 10 shown in Figure 2 is in the released state as described above. The permanent electromagnet 10 does not attract or hold the magnetic material W.

[0026] The coil 10c is wound around the outer circumference of each of the multiple second permanent magnets 10b. The coil 10c is electrically connected to the power supply 42 via a voltage application circuit 44. The power supply 42 is a DC power supply that applies a voltage to the coil 10c. The control device 40 controls the permanent electromagnet 10 by operating the voltage application circuit 44.

[0027] The control device 40 operates the voltage application circuit 44, applying a voltage from the power supply 42 to the coil 10c, causing current to flow through the coil 10c. Depending on the direction of the current flowing through the coil 10c, the magnetization direction of the second permanent magnet 10b can be reversed. A permanent electromagnet 10 in which the magnetization directions of the six second permanent magnets 10b shown in Figure 2 are reversed will be described later with reference to Figure 3.

[0028] The control device 40 includes an arithmetic unit 60 and a storage unit 62. The arithmetic unit 60 includes a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In other words, the arithmetic unit 60 includes processing circuitry.

[0029] The memory unit 62 includes volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory) or flash memory. The volatile memory is used as the processor's working memory. The non-volatile memory stores programs executed by the processor and other necessary data.

[0030] The arithmetic unit 60 includes a grouping unit 70 and a power supply control unit 72. The grouping unit 70 and the power supply control unit 72 are realized when the arithmetic unit 60 executes a program stored in the storage unit 62. At least a portion of the grouping unit 70 and the power supply control unit 72 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or by an electronic circuit including discrete devices.

[0031] The grouping unit 70 divides the multiple second permanent magnets 10b into multiple magnet groups G. The grouping is performed such that each magnet group G includes at least one second permanent magnet 10b. In this embodiment, each magnet group G includes one second permanent magnet 10b. An example of multiple magnet groups G in this embodiment will be described later with reference to Figure 4.

[0032] The current control unit 72 applies a voltage from the power supply 42 to the coil 10c wound around the outer circumference of each second permanent magnet 10b included in each magnet group G. This applied voltage is, for example, a positive voltage. When a positive voltage is applied to the coil 10c, current flows through the coil 10c in a first direction. The current control unit 72 sequentially performs this current control for each magnet group G, setting the magnetization direction of the second permanent magnet 10b to the direction corresponding to the attracted state.

[0033] The energization control unit 72 performs energization control sequentially for each magnet group G, and also performs energization stop control to stop the application of the applied voltage. That is, the energization control unit 72 performs energization control and energization stop control after energization control for each magnet group G. Due to the energization stop control, no current flows through the coil 10c. As a result, the power consumption of the permanent electromagnet 10 is reduced. Even after the energization stop control, the magnetization direction of the second permanent magnet 10b is maintained in the direction corresponding to the attracted state.

[0034] The power supply control unit 72 applies a negative voltage from the power supply 42 to the coil 10c. When a negative voltage is applied to the coil 10c, current flows through the coil 10c in a second direction, which is opposite to the first direction. The power supply control unit 72 performs power supply control to set the magnetization direction of the second permanent magnet 10b to the direction corresponding to the release state. When performing power supply control, the power supply control unit 72 also performs power supply stop control to stop the application of the applied voltage. No current flows through the coil 10c. Even after the power supply stop control, the magnetization direction of the second permanent magnet 10b is maintained in the direction corresponding to the release state.

[0035] In the released state of the permanent electromagnet 10 shown in Figure 2, the energizing control unit 72 sequentially performs energizing control for each magnet group G to change the magnetization direction of the second permanent magnet 10b to the direction corresponding to the adsorption state. As a result, the magnetization direction of each of the six second permanent magnets 10b is reversed. This switches the permanent electromagnet 10 from the released state to the adsorption state. In this case, the permanent electromagnet 10 possesses an adsorption force and can attract the magnetic material W. Figure 3 shows the state in which the permanent electromagnet 10 has attracted the magnetic material W.

[0036] The magnetization direction of the second permanent magnet 10b shown in Figure 3 is opposite to that of the second permanent magnet 10b shown in Figure 2. Therefore, in the six second permanent magnets 10b arranged from left to right, the magnetization directions of adjacent second permanent magnets 10b are opposite to each other. For example, the magnetic pole at the end of the second permanent magnet 10b #1 covered by the top yoke 10t is the south pole, and the magnetic pole at the opposite end of the second permanent magnet 10b #1 is the north pole. As described above, the magnetic pole at one end of the first permanent magnet 10a that abuts against the right side surface of the top yoke 10t covering the end of the second permanent magnet 10b #1 is the south pole, and the magnetic pole at the other end of the first permanent magnet 10a is the north pole.

[0037] The magnetic pole of the end of the second permanent magnet 10b#2 covered by the top yoke 10t that abuts the other end of the first permanent magnet 10a is the north pole, and the magnetic pole of the opposite end of the second permanent magnet 10b#2 is the south pole. As described above, the north-magnetized end of the second permanent magnet 10b#1 and the south-magnetized end of the second permanent magnet 10b#2 are covered by a bottom yoke (not shown).

[0038] Let's explain an example of magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2. Magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#2 passes through the top yoke 10t covering the second permanent magnet 10b#2 and enters the magnetic material W. Magnetic flux B passing through the magnetic material W and exiting from the magnetic material W passes through the top yoke 10t covering the second permanent magnet 10b#1 and enters the south pole of the second permanent magnet 10b#1. Magnetic flux B entering from the south pole and exiting from the north pole of the second permanent magnet 10b#1 passes through the bottom yoke and enters the south pole of the second permanent magnet 10b#2.

[0039] Let's explain an example of magnetic flux B passing through the first permanent magnet 10a between two top yokes 10t that cover the second permanent magnets 10b#1 and 10b#2, respectively. The magnetic flux B that enters from the south pole and exits from the north pole of the first permanent magnet 10a, which is in contact with the right side surface of the top yoke 10t that covers the end of the second permanent magnet 10b#1, passes through the top yoke 10t that covers the second permanent magnet 10b#2 and enters the magnetic material W. The magnetic flux B that passes through the magnetic material W and exits the magnetic material W passes through the top yoke 10t that covers the second permanent magnet 10b#1 and enters the south pole of the first permanent magnet 10a.

[0040] The magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2, and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#1 and 10b#2 respectively, both pass through the magnetic material W.

[0041] As described above, the magnetic pole at the end of the second permanent magnet 10b#2 covered by the top yoke 10t is the north pole, and the magnetic pole at the opposite end of the second permanent magnet 10b#2 is the south pole. The magnetic pole at one end of the first permanent magnet 10a, which is in contact with the right side surface of the top yoke 10t covering the end of the second permanent magnet 10b#2, is the north pole, and the magnetic pole at the other end of the first permanent magnet 10a is the south pole.

[0042] The magnetic pole at the end of the second permanent magnet 10b#3, which is covered by the top yoke 10t that abuts the other end of the first permanent magnet 10a, is the south pole, and the magnetic pole at the opposite end of the second permanent magnet 10b#3 is the north pole. As described above, the north-magnetic end of the second permanent magnet 10b#3 is covered by a bottom yoke (not shown), similar to the south-magnetic end of the second permanent magnet 10b#2.

[0043] An example of the magnetic flux B passing through the second permanent magnets 10b#2 and 10b#3 will be described. The magnetic flux B that enters from the S pole of the second permanent magnet 10b#2 and exits from the N pole enters the magnetic body W through the top yoke 10t covering the second permanent magnet 10b#2. The magnetic flux B that passes through the magnetic body W and exits from the magnetic body W enters the S pole of the second permanent magnet 10b#3 through the top yoke 10t covering the second permanent magnet 10b#3. The magnetic flux B that enters from the S pole of the second permanent magnet 10b#3 and exits from the N pole enters the S pole of the second permanent magnet 10b#2 through the bottom yoke.

[0044] An example of the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t respectively covering the second permanent magnets 10b#2 and 10b#3 will be described. The magnetic flux B that enters from the S pole of the first permanent magnet 10a where the left side surface of the top yoke 10t covering the end of the second permanent magnet 10b#3 abuts and exits from the N pole enters the magnetic body W through the top yoke 10t covering the second permanent magnet 10b#2. The magnetic flux B that passes through the magnetic body W and exits from the magnetic body W enters the S pole of the first permanent magnet 10a through the top yoke 10t covering the second permanent magnet 10b#3.

[0045] Both the magnetic flux B passing through the second permanent magnets 10b#2 and 10b#3 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t respectively covering the second permanent magnets 10b#2 and 10b#3 pass through the magnetic body W.

[0046] Similarly, both the magnetic flux B passing through the second permanent magnets 10b#3 and 10b#4 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t respectively covering the second permanent magnets 10b#3 and 10b#4 pass through the magnetic body W. Both the magnetic flux B passing through the second permanent magnets 10b#4 and 10b#5 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t respectively covering the second permanent magnets 10b#4 and 10b#5 pass through the magnetic body W.

[0047] The magnetic flux B passing through the second permanent magnets 10b#5 and 10b#6 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t covering the second permanent magnets 10b#5 and 10b#6 respectively both pass through the magnetic body W. That is, all the magnetic fluxes B shown in FIG. 3 pass through the magnetic body W. Thus, when at least a part of the magnetic circuit formed by the magnetic flux B is formed including the magnetic body W, the permanent electromagnetic magnet 10 has adsorption force. Therefore, the permanent electromagnetic magnet 10 shown in FIG. 3 is in the adsorption state as described above. The permanent electromagnetic magnet 10 can adsorb and hold the magnetic body W on the adsorption surface As formed by all of the plurality of top yokes 10t.

[0048] As described above, the energization control in which the energization control unit 72 makes the magnetization direction of the second permanent magnet 10b in the direction corresponding to the adsorption state is sequentially performed for each magnet group G. FIG. 4 is a diagram illustrating a plurality of magnet groups G. The permanent electromagnetic magnet 10 shown in FIG. 4 is the permanent electromagnetic magnet 10 in the release state similar to that in FIG. 2. Similar to FIG. 2, in the permanent electromagnetic magnet 10 shown in FIG. 4, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged side by side from left to right.

[0049] The grouping unit 70 of the control device 40 groups the six second permanent magnets 10b into six magnet groups G. As described above, in the present embodiment, the grouping is performed such that each magnet group G includes one second permanent magnet 10b. The magnet group G#1 includes the second permanent magnet 10b#1 arranged at the leftmost position. The magnet group G#2 includes the second permanent magnet 10b#2 arranged second from the left and fifth from the right. The magnet group G#3 includes the second permanent magnet 10b#3 arranged third from the left and fourth from the right.

[0050] Magnet group G#4 includes a second permanent magnet 10b#4 positioned fourth from the left and third from the right. Magnet group G#5 includes a second permanent magnet 10b#5 positioned fifth from the left and second from the right. Magnet group G#6 includes a second permanent magnet 10b#6 positioned furthest to the right. The energization control unit 72 of the control device 40 sequentially performs energization control to set the magnetization direction of the second permanent magnet 10b to the direction corresponding to the attracted state, and then performs energization stop control after the energization control, for each magnet group G.

[0051] Figure 5 illustrates the changes in the attractive forces Fa and Fs of the permanent electromagnet 10 associated with energization control and de-energization control for each magnet group G. In the permanent electromagnet 10 illustrated in Figure 4, energization control and de-energization control are performed sequentially for each of the six magnet groups G to set the magnetization direction of the second permanent magnet 10b contained in each of the six magnet groups G to the direction corresponding to the attractive state. Once the energization control and de-energization control for the six magnet groups G has been completed once, another round of energization control and de-energization control for the six magnet groups G is performed. Figure 5 shows the changes in the attractive forces Fa and Fs of the permanent electromagnet 10 associated with the energization control and de-energization control in the first round and the subsequent second round.

[0052] Figure 5 shows the change in the attractive force Fa of the permanent electromagnet 10 with energization control and the change in the attractive force Fs of the permanent electromagnet 10 with energization deactivation control. When energized, a magnetic force is generated by the coil 10c, so the attractive force Fa is greater than the attractive force Fs.

[0053] In the deactivated permanent electromagnet 10, at the beginning of the first cycle, energization control is performed to set the magnetization direction of the second permanent magnet 10b included in magnet group G#1 to the direction corresponding to the attracted state. Subsequently, energization deactivation control is performed in magnet group G#1. Next, energization control is performed to set the magnetization direction of the second permanent magnet 10b included in magnet group G#2 to the direction corresponding to the attracted state. Subsequently, energization deactivation control is performed in magnet group G#2.

[0054] The magnet group G#1, which has undergone energization control, and the magnet group G#2, which will be subjected to energization control next, are adjacent to each other. This arrangement allows for a more efficient increase in the magnetic flux B passing through the magnetic material W through energization control compared to the case where the magnet group G#1 and the magnet group G#2 are spaced apart. Consequently, the attractive force Fs of the permanent electromagnet 10 in the attracted state is increased.

[0055] Similarly, the first cycle of energization control and de-energy control is performed sequentially for magnet groups G#3, G#4, G#5, and G#6. At this time, the magnet group G that has been energized and the magnet group G that will be energized next are adjacent to each other. In this way, as the energization control and de-energy control are performed sequentially for each magnet group G, the attractive force Fa of the permanent electromagnet 10 due to energization control and the attractive force Fs of the permanent electromagnet 10 due to de-energy control both increase. When the first cycle of energization control and de-energy control for magnet group G#6 is completed, the attractive force Fa is at a value of Fa1 and the attractive force Fs is at a value of Fs1.

[0056] Figure 5 shows the attractive force Fas of the permanent electromagnet 10 under energization control and the attractive force Fss of the permanent electromagnet 10 under energization deactivation control in the comparative example. In the comparative example, simultaneous energization control and simultaneous deactivation control are performed to collectively change the magnetization direction of the six second permanent magnets 10b included in the permanent electromagnet 10 exemplified in Figure 4 to the direction corresponding to the attractive state. When simultaneous energization control is performed, current flows simultaneously through the six coils 10c that wind each of the six second permanent magnets 10b. As a result, a magnetic force is generated by all six coils 10c.

[0057] Therefore, the attractive force Fas of the permanent electromagnet 10 is large when the energization control is performed. In that case, in the example shown in Figure 1A, the permanent electromagnet 10 may attract two or more magnetic materials W. In contrast, when the energization control is performed sequentially for each magnet group G as in this embodiment, the attractive force Fa of the permanent electromagnet 10 is suppressed to a value Fa1 or Fa2, which is lower than the attractive force Fas described above. The attractive force Fa at the end of the first cycle of energization control is value Fa1, and the attractive force Fa at the end of the second cycle of energization control is value Fa2.

[0058] Furthermore, in the comparative example, the attractive force Fss of the permanent electromagnet 10 following the simultaneous de-energization control after simultaneous energization control is higher than the attractive force Fs1 value at the stage when the first round of energization control and de-energization control is completed in this embodiment. In the process in which energization control and de-energization control are performed sequentially for each magnet group G as in this embodiment, there are second permanent magnets 10b whose magnetization direction has not yet been reversed because energization control has not yet been performed. Due to the influence of these second permanent magnets 10b whose magnetization direction has not been reversed, the attractive force Fs associated with the energization control and de-energization control in each magnet group G is suppressed.

[0059] In other words, when the energization control and de-energization control are performed sequentially for each magnet group G as in this embodiment, the attractive forces Fa and Fs of the permanent electromagnet 10 are suppressed. However, it is conceivable that the value of the attractive force Fs Fs1 at the end of the first round of energization control and de-energization control may be too large, potentially causing the permanent electromagnet 10 to attract two or more magnetic materials W. In that case, the energization control and de-energization control may be performed on only some of the six second permanent magnets 10b, rather than all of them. The attractive force Fs can be adjusted by adjusting the number of magnet groups G on which the energization control and de-energization control are performed.

[0060] After the first cycle of energization control and de-energy control is completed, the second cycle of energization control and de-energy control is performed, allowing the attractive force Fs to approach the attractive force Fss of the permanent electromagnet 10 that occurs after the simultaneous energization control and subsequent simultaneous de-energy control. In the example shown in Figure 5, in the permanent electromagnet 10 in the attractive state, the first step of the second cycle is to energize the second permanent magnet 10b included in magnet group G#1 so that its magnetization direction corresponds to the attractive state. Subsequently, de-energy control is performed in magnet group G#1. Similarly, the second cycle of energization control and de-energy control is performed sequentially in magnet groups G#2, G#3, G#4, G#5, and G#6.

[0061] In this way, as the energization control and de-energy control are performed sequentially for each magnet group G, the attractive force Fa of the permanent electromagnet 10 associated with the energization control and the attractive force Fs of the permanent electromagnet 10 associated with the de-energy control both increase. When the second round of energization control and de-energy control for magnet group G#6 is completed, the attractive force Fa shows a value of Fa2, and the attractive force Fs shows a value of Fs2. The value Fs2 of the attractive force Fs at the completion of the second round of energization control and de-energy control can approach the attractive force Fss of the permanent electromagnet 10 associated with the simultaneous de-energy control after the simultaneous energization control. In the example shown in Figure 5, the value Fs2 matches the attractive force Fss.

[0062] In that case, the third cycle of energization control and de-energy control is unnecessary. However, if the value Fs2 is smaller than the adsorption force Fss, further energization control and de-energy control may be performed from the third cycle onward. This will bring the value Fs2 closer to the adsorption force Fss.

[0063] Furthermore, it is conceivable that the permanent electromagnet 10 may attract two or more magnetic materials W if the value of the attractive force Fs Fs2 at the end of the second cycle of energization control and de-energization control is too large. In that case, in the second cycle, energization control and de-energization control of the second permanent magnets 10b may be performed on only some of the six second permanent magnets 10b, rather than all of them.

[0064] In other words, the energization control unit 72 of the control device 40 performs the first round of energization control and de-energy control for all of the multiple magnet groups G. Subsequently, the energization control unit 72 sequentially performs the second round of energization control and de-energy control for at least some of the multiple magnet groups G, for each magnet group G. The attraction force Fs can be adjusted by adjusting the number of magnet groups G on which the second round of energization control and de-energy control is performed.

[0065] In this embodiment, the order of the magnet groups G when the energization control and de-energy control are performed sequentially for each magnet group G from the second round onward is the same as that of the first round of energization control and de-energy control, but it may be different.

[0066] Figure 6 is a flowchart illustrating the processing procedure for energizing and de-energizing each magnet group G. This processing procedure is performed by the calculation unit 60 of the control device 40 executing a program stored in the storage unit 62. When this processing procedure is started, in step S1, the grouping unit 70 divides the multiple second permanent magnets 10b into multiple magnet groups G. In step S2, the energizing control unit 72 determines which magnet group G will be subjected to energizing control.

[0067] In step S3, the energization control unit 72 controls the energization of the coil 10c wound around the outer circumference of the second permanent magnet 10b, which is included in the magnet group G determined in step S2. In step S4, the energization control unit 72 controls the energization to stop the energization control performed in step S3. In step S5, the energization control unit 72 determines whether the energization control and the energization to stop control have been completed. If the result in step S5 is YES, this process procedure ends. If the result in step S5 is NO, this process procedure returns to step S2.

[0068] The embodiments described above may be modified as follows. In the following modifications, explanations that overlap with those in the embodiments will be omitted. Also, in the figures used in the following modifications, components identical to those described in the embodiments will be denoted by the same reference numerals.

[0069] (Modification 1) In the embodiment described above, each magnet group G includes one second permanent magnet 10b. However, each magnet group G may include at least two second permanent magnets 10b whose magnetization directions are opposite to each other and which are adjacent to each other. Figures 7A and 7B illustrate the change in magnetic flux B in response to the energization control of the first magnet group G when the magnet group G includes two adjacent second permanent magnets 10b.

[0070] The permanent electromagnet 10 shown in Figure 7A is the same disengaged permanent electromagnet 10 as in Figure 2. Similar to Figure 2, in the permanent electromagnet 10 shown in Figure 7A, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged from left to right. Magnet group G#1 includes the second permanent magnet 10b#1, which is the leftmost, and the second permanent magnet 10b#2, which is the second from the left and the fifth from the right. The second permanent magnets 10b#1 and 10b#2 included in magnet group G#1 have opposite magnetization directions and are adjacent to each other.

[0071] The permanent electromagnet 10 shown in Figure 7B represents the state after energization control and de-energization control have been performed on the permanent electromagnet 10 shown in Figure 7A, which directs the magnetization direction of the two second permanent magnets 10b included in magnet group G#1 to the direction corresponding to the attracted state. The magnetization directions of the second permanent magnets 10b#1 and 10b#2 are reversed in Figure 7B compared to Figure 7A. As a result, the magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t covering the second permanent magnets 10b#1 and 10b#2, respectively, both pass through the magnetic material W.

[0072] Figures 8A and 8B illustrate the change in magnetic flux B in response to the energization control of the first magnet group G when the magnet group G includes two second permanent magnets 10b that are spaced apart and not adjacent to each other. The permanent electromagnet 10 shown in Figure 8A is the same disengaged permanent electromagnet 10 as in Figure 2. Similar to Figure 2, in the permanent electromagnet 10 shown in Figure 8A, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged from left to right.

[0073] Magnet group G#1 includes a second permanent magnet 10b#1 positioned furthest to the left and a second permanent magnet 10b#5 positioned fifth from the left and second from the right. The second permanent magnets 10b#1 and 10b#5 included in magnet group G#1 have the same magnetization direction and are spaced apart from each other but not adjacent. The permanent electromagnet 10 shown in Figure 8B shows the state after energization control and energization deactivation control have been performed on the permanent electromagnet 10 shown in Figure 8A to change the magnetization direction of the two second permanent magnets 10b included in magnet group G#1 to the direction corresponding to the attracted state.

[0074] The magnetic flux B passing through the second permanent magnet 10b#1 is relatively weak because it passes outside the permanent electromagnet 10 after passing through the magnetic material W. The magnetic flux B passing through the second permanent magnet 10b#5 is also relatively weak because it passes outside the permanent electromagnet 10 after passing through the magnetic material W. Therefore, the permanent electromagnet 10 can appropriately and stably possess an attractive force when the magnet group G includes a plurality of adjacent second permanent magnets 10b whose magnetization directions are opposite to each other, as shown in Figures 7A and 7B, compared to when it includes a plurality of different second permanent magnets 10b whose magnetization directions are opposite to each other and are adjacent to each other, as shown in Figures 8A and 8B.

[0075] (Modification 2) In the embodiment described above, the energization control is performed on all second permanent magnets 10b, but is not limited to this. Figure 9 is a diagram illustrating a plurality of magnet groups G and the second permanent magnets 10b of the first part P1 and the second part P2. The permanent electromagnet 10 shown in Figure 9 is a permanent electromagnet 10 in the same deactivated state as in Figure 2. Similar to Figure 2, in the permanent electromagnet 10 shown in Figure 9, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged from left to right.

[0076] In this modified example 2, the multiple second permanent magnets 10b of the permanent electromagnet 10 include the second permanent magnets 10b of the first portion P1 and the second permanent magnets 10b of the second portion P2 which are different from the first portion P1. The second permanent magnets 10b of the first portion P1 and the second permanent magnets 10b of the second portion P2 are set in advance by the user or the like.

[0077] In the example shown in Figure 9, the second permanent magnet 10b of the first part P1 includes the second permanent magnet 10b#1 located on the far left, the second permanent magnet 10b#2 located second from the left and fifth from the right, the second permanent magnet 10b#5 located fifth from the left and second from the right, and the second permanent magnet 10b#6 located on the far right. The second permanent magnet 10b of the second part P2 includes the second permanent magnet 10b#3 located third from the left and fourth from the right, and the second permanent magnet 10b#4 located fourth from the left and third from the right.

[0078] The grouping unit 70 of the control device 40 divides the six second permanent magnets 10b into three magnet groups G. Each magnet group G includes two second permanent magnets 10b whose magnetization directions are opposite to each other and which are adjacent to each other.

[0079] In the example shown in Figure 9, magnet group G#1 includes the second permanent magnet 10b#1 located furthest to the left and the second permanent magnet 10b#2 located second from the left and fifth from the right. Magnet group G#2 includes the second permanent magnet 10b#5 located fifth from the left and second from the right and the second permanent magnet 10b#6 located furthest to the right. Magnet group G#3 includes the second permanent magnet 10b#3 located third from the left and fourth from the right and the second permanent magnet 10b#4 located fourth from the left and third from the right.

[0080] The energization control unit 72 of the control device 40 sequentially performs energization control and energization deactivation control for each magnet group G of the second permanent magnet 10b of the first part P1. As a result, the energization control unit 72 causes the permanent electromagnet 10 to attract the magnetic material W with a first attractive force F1. Since the first attractive force F1 is not a strong attractive force, in the example shown in Figure 1A, the possibility of the permanent electromagnet 10 attracting two or more magnetic materials W can be reduced. Figure 10A shows the state in which energization control and energization deactivation control have been performed for each magnet group G of the second permanent magnet 10b of the first part P1.

[0081] In the permanent electromagnet 10 shown in Figure 9, energization control and de-energy control are performed to change the magnetization direction of the second permanent magnets 10b#1, 10b#2, 10b#5, and 10b#6 of the first part P1 to the direction corresponding to the attracted state. That is, the energization control and de-energy control are performed for magnet group G#1, and then the energization control and de-energy control are performed for magnet group G#2.

[0082] Because the energization control and energization deactivation control were performed on magnet group G#1, the magnetization directions of the second permanent magnets 10b#1, 10b#2, 10b#5, and 10b#6 of the first part P1 are reversed in Figure 10A compared to Figure 9.

[0083] As a result, the magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2, and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#1 and 10b#2 respectively, both pass through the magnetic material W. The magnetic flux B passing through the second permanent magnets 10b#1 and 10b#3, and the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#2 and 10b#3 respectively, also passes through the magnetic material W.

[0084] The magnetic flux B passing through the second permanent magnets 10b#5 and 10b#6, and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#5 and 10b#6 respectively, both pass through the magnetic material W. The magnetic flux B passing through the second permanent magnets 10b#4 and 10b#6, and the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#4 and 10b#5 respectively, also passes through the magnetic material W. The permanent electromagnet 10 attracts the magnetic material W with a first attracting force F1 at the adsorption surface As.

[0085] The power supply control unit 72 of the control device 40 further sequentially performs power supply control and power supply de-power supply control for each magnet group G of the second permanent magnet 10b of the second part P2. As a result, the power supply control unit 72 causes the permanent electromagnet 10 to attract the magnetic material W with a second attractive force F2 which is stronger than the first attractive force F1. When the permanent electromagnet 10 has attracted the magnetic material W with the first attractive force F1, the robot 30 pulls the permanent electromagnet 10 away from the remaining magnetic material W that has been placed on it. In this case, the possibility of two or more magnetic materials W being attracted by the second attractive force F2 is suppressed.

[0086] In the example shown in Figure 1B, inertial force may be generated by the movement of the robot 30 transporting the magnetic material W. When the permanent electromagnet 10 is holding the magnetic material W with a first attraction force F1, the magnetic material W may detach from the permanent electromagnet 10 due to the inertial force. However, in this modified example 2, the permanent electromagnet 10 holds the magnetic material W with a stronger second attraction force F2, so the possibility of the magnetic material W detaching from the permanent electromagnet 10 during transport is suppressed. In other words, the stability of the attraction and transport of the magnetic material W can be improved.

[0087] Figure 10B shows the state in which energization control and energization deactivation control are performed for each magnet group G on the second permanent magnet 10b of the second part P2. Figure 10B shows the result of further energization control and energization deactivation control being performed on the permanent electromagnet 10 shown in Figure 10A, so that the magnetization direction of the second permanent magnets 10b#3 and 10b#4 of the second part P2 is in the direction corresponding to the attracted state. That is, the energization control and energization deactivation control are performed on magnet group G#3.

[0088] Because the energization control and de-energization control were performed on magnet group G#3, the magnetization direction of the second permanent magnets 10b#3 and 10b#4 of the second part P2 is reversed in Figure 10B compared to Figure 10A. As a result, the magnetic flux B passing through the second permanent magnets 10b#3 and 10b#4 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#3 and 10b#4 respectively pass through the magnetic material W.

[0089] In other words, the magnetization direction of all the second permanent magnets 10b shown in Figure 10B is oriented in the direction corresponding to the adsorption state, and all the magnetic flux B passes through the magnetic material W. Therefore, the second adsorption force F2 of the magnetic material W by the permanent electromagnet 10 is greater than the first adsorption force F1 of the magnetic material W by the permanent electromagnet 10 shown in Figure 10A. The permanent electromagnet 10 attracts the magnetic material W with the second adsorption force F2 at the adsorption surface As.

[0090] Figure 11 illustrates the change in the attractive force of the permanent electromagnet 10 in accordance with the energization control and de-energization control for each magnet group G. As described above, the energization control and de-energization control are sequentially performed for each magnet group G on the second permanent magnet 10b of the first part P1. That is, first the energization control and de-energization control are performed on magnet group G#1. Next, the energization control and de-energization control are performed on magnet group G#2.

[0091] At this stage, the permanent electromagnet 10 possesses a first attractive force F1. The permanent electromagnet 10 attracts one of the multiple magnetic materials W placed on top of it with the first attractive force F1. With one magnetic material W attracted by the first attractive force F1, the permanent electromagnet 10 is pulled away from the remaining magnetic materials W placed on it.

[0092] Next, for the second permanent magnet 10b of the second part P2, energization control and energization deactivation control are sequentially performed for each magnet group G. That is, the energization control and energization deactivation control are performed for magnet group G#3. At this stage, the permanent electromagnet 10 has a second attractive force F2 that is greater than the first attractive force F1. The magnetic material W is transported while being attracted by the permanent electromagnet 10 with the second attractive force F2.

[0093] (Modification 3) In the above-described embodiment, the permanent electromagnet 10 in the released state is illustrated in Figure 2. All of the magnetic flux B shown in Figure 2 is confined within the permanent electromagnet 10. In this case, none of the magnetic flux B passes through the magnetic material W. In contrast, if the magnetization direction of some of the second permanent magnets 10b is oriented in the direction corresponding to the adsorption state, some of the magnetic flux B passes through the adsorption surface As, which can generate a slight adsorption force on the permanent electromagnet 10. Even in this case, the adsorption force is not strong enough to attract the magnetic material W. That is, the permanent electromagnet 10 does not attract the magnetic material W.

[0094] Therefore, instead of being in a released state, the permanent electromagnet 10 that does not attract the magnetic material W may have some of its second permanent magnets 10b fixed in a direction corresponding to the attracting state. Figure 12A shows the state in which the magnetization direction of the second permanent magnets 10b of the first part Q1 is oriented in a direction corresponding to the attracting state. In the permanent electromagnet 10 shown in Figure 12A, six second permanent magnets 10b#1, 10b#2, 10b#3, 10b#4, 10b#5, and 10b#6 are arranged from left to right.

[0095] In this modified example 3, the multiple second permanent magnets 10b of the permanent electromagnet 10 include the second permanent magnets 10b of the first part Q1 and the second permanent magnets 10b of the second part Q2 which are different from the first part Q1. The second permanent magnets 10b of the first part Q1 and the second permanent magnets 10b of the second part Q2 are set in advance by the user or the like.

[0096] In the example shown in Figure 12A, the second permanent magnet 10b of the first part Q1 includes the second permanent magnet 10b#3 positioned third from the left and fourth from the right, and the second permanent magnet 10b#4 positioned fourth from the left and third from the right. The second permanent magnet 10b of the second part Q2 includes the second permanent magnet 10b#1 positioned furthest to the left, the second permanent magnet 10b#2 positioned second from the left and fifth from the right, the second permanent magnet 10b#5 positioned fifth from the left and second from the right, and the second permanent magnet 10b#6 positioned furthest to the right.

[0097] The magnetization directions of the second permanent magnets 10b#3 and 10b#4 in the first part Q1 are reversed in Figure 12A compared to Figure 2. The magnetization directions of the second permanent magnets 10b#3 and 10b#4 in the first part Q1 are always fixed in the direction corresponding to the attracted state, as shown in Figure 12A. The magnetization directions of the second permanent magnets 10b#1, 10b#2, 10b#5 and 10b#6 in the second part Q2 are in the direction corresponding to the released state in the example shown in Figure 12A.

[0098] As a result, the magnetic flux B passing through the second permanent magnets 10b#3 and 10b#4, and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#3 and 10b#4 respectively, both pass through the adsorption surface As. The magnetic flux B passing through the second permanent magnets 10b#2 and 10b#5, the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#2 and 10b#3 respectively, and the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#4 and 10b#5 respectively, also passes through the adsorption surface As.

[0099] Therefore, a slight attraction force is generated in the permanent electromagnet 10. However, the permanent electromagnet 10 as a whole does not generate an attraction force sufficient to attract the magnetic material W. This state of the permanent electromagnet 10 that does not attract the magnetic material W, as shown in Figure 12A, is called the non-attractive state.

[0100] The grouping unit 70 of the control device 40 groups the remaining four second permanent magnets 10b, excluding the second permanent magnets 10b#3 and 10b#4 of the first portion Q1 whose magnetization direction is fixed, into two magnet groups G. That is, the four second permanent magnets 10b#1, 10b#2, 10b#5, and 10b#6 are grouped into magnet group G#1, which includes the two second permanent magnets 10b#1 and 10b#2, and magnet group G#2, which includes the two second permanent magnets 10b#5 and 10b#6. Each magnet group G includes two second permanent magnets 10b whose magnetization directions are opposite to each other and which are adjacent to each other.

[0101] The energization control unit 72 of the control device 40 sequentially performs energization control and energization deactivation control for each magnet group G of the second permanent magnet 10b of the second part Q2. This energization control reverses the magnetization direction of the second permanent magnet 10b of the second part Q2 to the direction corresponding to the adsorption state. As a result, the energization control unit 72 causes the magnetic material W to be attracted to the permanent electromagnet 10. Figure 12B shows the state in which the magnetization direction of the second permanent magnet 10b of the second part Q2 is facing the direction corresponding to the adsorption state.

[0102] Figure 12B shows the results of energization control and de-energization control performed for each magnet group G in the permanent electromagnet 10 shown in Figure 12A, to change the magnetization direction of the second permanent magnets 10b#1, 10b#2, 10b#5, and 10b#6 of the second part Q2 to the direction corresponding to the attracted state. Specifically, the energization control and de-energization control are performed sequentially for magnet groups G#1 and G#2.

[0103] Because the energization control and de-energization control were performed sequentially for magnet groups G#1 and G#2, the magnetization directions of the second permanent magnets 10b#1, 10b#2, 10b#5, and 10b#6 in the second part Q2 are reversed in Figure 12B compared to Figure 12A. As a result, the magnetic flux B passing through the second permanent magnets 10b#1 and 10b#2 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t covering the second permanent magnets 10b#1 and 10b#2 respectively pass through the magnetic material W.

[0104] The magnetic flux B passing through the second permanent magnets 10b#2 and 10b#3 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#2 and 10b#3 both pass through the magnetic material W. The magnetic flux B passing through the second permanent magnets 10b#4 and 10b#5 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#4 and 10b#5 both pass through the magnetic material W. The magnetic flux B passing through the second permanent magnets 10b#5 and 10b#6 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#5 and 10b#6 both pass through the magnetic material W.

[0105] Furthermore, as described above, the magnetization directions of the second permanent magnets 10b#3 and 10b#4 in the first part Q1 are always fixed in the direction corresponding to the attracted state. Therefore, the magnetic flux B passing through the second permanent magnets 10b#3 and 10b#4 and the magnetic flux B passing through the first permanent magnet 10a between the two top yokes 10t that cover the second permanent magnets 10b#3 and 10b#4 respectively both pass through the magnetic material W.

[0106] In other words, the magnetization direction of all the second permanent magnets 10b shown in Figure 12B is oriented in the direction corresponding to the adsorption state, and all the magnetic flux B passes through the magnetic material W. Therefore, the permanent electromagnet 10 enters the adsorption state and attracts the magnetic material W at the adsorption surface As. In this modified example 3, when changing the permanent electromagnet 10 from a non-adsorbing state to an adsorbing state, it is only necessary to perform energization control to change the magnetization direction of the second permanent magnets 10b of the second part Q2 to the direction corresponding to the adsorption state. It is not necessary to perform this energization control for all the second permanent magnets 10b. Therefore, the power consumption required to change the permanent electromagnet 10 from a non-adsorbing state to an adsorbing state can be reduced.

[0107] The same applies when changing the permanent electromagnet 10 from the attracted state shown in Figure 12B to the non-attracted state shown in Figure 12A. In the example shown in Figure 12B, the magnetization directions of the second permanent magnets 10b#3 and 10b#4 in the first part Q1 and the magnetization directions of the second permanent magnets 10b#1, 10b#2, 10b#5 and 10b#6 in the second part Q2 are all directions corresponding to the attracted state.

[0108] The energization control unit 72 of the control device 40 sequentially performs energization control and energization deactivation control on the second permanent magnet 10b of the second part Q2. This energization control reverses the magnetization direction of the second permanent magnet 10b of the second part Q2 to the direction corresponding to the deactivation state. As a result, the energization control unit 72 detaches the magnetic material W from the permanent electromagnet 10. The permanent electromagnet 10 then enters the non-adherent state shown in Figure 12A.

[0109] In this modified example 3, when changing the permanent electromagnet 10 from an attracted state to a non-attracted state, it is only necessary to perform energization control on the second permanent magnet 10b of the second part Q2 to change its magnetization direction to the direction corresponding to the released state. It is not necessary to perform this energization control on all of the second permanent magnets 10b. Therefore, the power consumption required to change the permanent electromagnet 10 from an attracted state to a non-attracted state can be reduced.

[0110] Figure 13 illustrates the change in the attractive force of the permanent electromagnet 10 in accordance with the energization control and energization deactivation control for each magnet group G. When the permanent electromagnet 10 is in the non-adherent state shown in Figure 12A, the permanent electromagnet 10 has an attractive force Fn. When energization control and energization deactivation control are performed on magnet group G#1 among the second permanent magnets 10b of the second part Q2, the permanent electromagnet 10 has an attractive force Fm1. This energization control reverses the magnetization direction of the second permanent magnet 10b to the direction corresponding to the attractive state.

[0111] When energization control and de-energization control are performed on the magnet group G#2 of the second permanent magnet 10b in the second part Q2, the permanent electromagnet 10 acquires an attractive force Fm2. When the permanent electromagnet 10 acquires an attractive force of F0 or more, the permanent electromagnet 10 is assumed to be in an attractive state capable of attracting the magnetic material W. In the example shown in Figure 13, since the attractive force Fm2 is greater than or equal to the predetermined value F0, the permanent electromagnet 10 is in an attractive state. Therefore, the permanent electromagnet 10 attracts the magnetic material W.

[0112] When the permanent electromagnet 10 is in the adsorption state shown in Figure 12B, the permanent electromagnet 10 has an adsorption force Fm2. When the energization control and de-energization control are performed on the second permanent magnet 10b of the second part Q2, the adsorption force decreases from Fm2 to Fn. This energization control reverses the magnetization direction of the second permanent magnet 10b to the direction corresponding to the release state. The permanent electromagnet 10 is in a non-adsorbent state. Therefore, the magnetic material W detaches from the permanent electromagnet 10.

[0113] (Modification 4) In the embodiment described above, the permanent electromagnet 10 attracts the magnetic material W with the adsorption surface As formed by all of the multiple top yokes 10t. However, if the magnetic material W is small, the adsorption surface As may be formed by only a portion of the top yokes 10t. In that case, the energization control may be performed only on the second permanent magnet 10b covered by the portion of the top yokes 10t.

[0114] Figure 14 is a schematic diagram showing the configuration of a permanent electromagnet 10 capable of attracting a magnetic material W, and the configuration of a control device 40 that controls the permanent electromagnet 10. The permanent electromagnet 10 shown in Figure 14 is the same as the permanent electromagnet 10 in the released state as in Figure 2. Figure 14 differs from Figure 2 in that the magnetic material W is small and the calculation unit 60 of the control device 40 further has a specific unit 74. In the example shown in Figure 14, because the magnetic material W is small, the attraction surface As is formed by a part of the top yoke 10t.

[0115] In other words, the adsorption surface As is formed not by all six top yokes 10t that cover each of the six second permanent magnets 10b, but by two top yokes 10t that cover two of the second permanent magnets 10b#3 and 10b#4, respectively.

[0116] Furthermore, the identification unit 74 can be realized by the calculation unit 60 executing a program stored in the storage unit 62. The identification unit 74 identifies the second permanent magnet 10b corresponding to the position of the magnetic material W when the permanent electromagnet 10 is released. The adsorption surface As is formed by the top yoke 10t that covers the second permanent magnet 10b corresponding to the position of the magnetic material W. In the example shown in Figure 14, the second permanent magnet 10b corresponding to the position of the magnetic material W are two second permanent magnets 10b#3 and 10b#4. The two second permanent magnets 10b#3 and 10b#4 are identified by the identification unit 74.

[0117] The identification of the second permanent magnet 10b corresponding to the position of the magnetic material W by the identification unit 74 may be performed in any way. For example, the second permanent magnet 10b corresponding to the position of the magnetic material W may be identified using Figure 15. Figure 15 is a diagram illustrating the change in the current flowing through the coil 10c of the permanent electromagnet 10 over time.

[0118] The specific unit 74 applies a specific voltage from the power supply 42 to each coil 10c that winds each second permanent magnet 10b of the permanent electromagnet 10, which is in the released state. The magnitude of the specific voltage is smaller than the magnitude of the applied voltage described above. Therefore, even if current flows through the coil 10c due to the application of the specific voltage to the coil 10c, the magnetization direction of the second permanent magnet 10b does not change.

[0119] Figure 15 shows graph Im when there is a magnetic material W near the top yoke 10t covering the second permanent magnet 10b, and graph In when there is no magnetic material W near the top yoke 10t. When a specific voltage is applied to the coil 10c at time Tsr, the current flowing through the coil 10c gradually increases in both graph Im and graph In, and reaches a constant value Ip corresponding to the specific voltage.

[0120] When the current flowing through coil 10c increases, the rate of increase is greater in graph In (when there is no magnetic material W) than in graph Im (when there is magnetic material W). In the example shown in Figure 15, at time Twr, after a predetermined time Tp has elapsed since a specific voltage was applied to coil 10c at time Tsr, the difference in current values ​​between graph In and graph Im is large. The predetermined time Tp is determined in advance according to a time constant τ obtained, for example, based on the inductance and resistance values ​​of coil 10c.

[0121] As shown in graph In, the current flowing through coil 10c at time Twr is value Inr when there is no magnetic material W. As shown in graph Im, the current flowing through coil 10c at time Twr is value Imr when there is a magnetic material W. The values ​​Inr and Imr are obtained by measurement. Using the values ​​Inr and Imr, a threshold value used by the identification unit 74 to identify the second permanent magnet 10b corresponding to the position of the magnetic material W is predetermined. The threshold value thus determined is stored in the storage unit 62.

[0122] The special unit 74 applies a special voltage from the power supply 42 to each coil 10c that winds each second permanent magnet 10b of the permanent electromagnet 10, which is in the released state. After a predetermined time Tp has elapsed since the application of the special voltage began, the special unit 74 obtains a measured value of the current flowing through each coil 10c from, for example, an ammeter (not shown).

[0123] If the measured value of the current flowing through each coil 10c is less than a threshold stored in the storage unit 62, the identification unit 74 determines that there is a magnetic material W near the top yoke 10t that covers the second permanent magnet 10b around which the coil 10c is wound. If the measured value of the current flowing through each coil 10c is equal to or greater than the threshold stored in the storage unit 62, the identification unit 74 determines that there is no magnetic material W near the top yoke 10t that covers the second permanent magnet 10b around which the coil 10c is wound.

[0124] As a result, the identification unit 74 can identify the second permanent magnet 10b corresponding to the position of the magnetic material W when the permanent electromagnet 10 is released. In the example shown in Figure 14, two second permanent magnets 10b#3 and 10b#4 are identified by the identification unit 74 as the second permanent magnet 10b corresponding to the position of the magnetic material W.

[0125] When the permanent electromagnet 10 is released, the energization control unit 72 of the control device 40 sequentially performs energization control and energization deactivation control for each magnet group G of the second permanent magnets 10b identified by the identification unit 74. This energization control reverses the magnetization direction of the second permanent magnets 10b identified by the identification unit 74 to the direction corresponding to the attracted state. In the example shown in Figure 14, energization control is performed on the two second permanent magnets 10b#3 and 10b#4, and the magnetization directions of the two second permanent magnets 10b#3 and 10b#4 are reversed. As a result, the energization control unit 72 causes the magnetic material W to be attracted to the permanent electromagnet 10.

[0126] In the state of attraction of the permanent electromagnet 10, the energization control unit 72 performs energization control and energization deactivation control on the second permanent magnet 10b identified by the identification unit 74. This energization control reverses the magnetization direction of the second permanent magnet 10b identified by the identification unit 74 to the direction corresponding to the release state. In the example shown in Figure 14, energization control is performed on the two second permanent magnets 10b#3 and 10b#4, and the magnetization directions of the two second permanent magnets 10b#3 and 10b#4 are reversed. As a result, the energization control unit 72 detaches the magnetic material W from the permanent electromagnet 10.

[0127] Figure 16 is a flowchart illustrating the processing procedure for energizing and de-energizing each magnet group G. This processing procedure is performed by the arithmetic unit 60 of the control device 40 executing a program stored in the storage unit 62. Using Figure 6, steps similar to those described above are denoted by the same reference numerals, and explanations are omitted as appropriate.

[0128] When this processing procedure is initiated, in step S21, the identification unit 74 identifies the second permanent magnet 10b corresponding to the position of the magnetic material W, while the permanent electromagnet 10 is in the released state. Once the processing in step S21 is completed, this processing procedure proceeds to step S1. The processing from steps S1 to S6 until the completion of this processing procedure is described above with reference to Figure 6 and is therefore omitted here.

[0129] In this modified example 4, the current is controlled only for the second permanent magnet 10b corresponding to the position of the magnetic material W. Therefore, the power consumption required to change the permanent electromagnet 10 from an attracted state to a non-attracted state, and the power consumption required to change the permanent electromagnet 10 from a non-attracted state to an attracted state can be reduced.

[0130] (Modification 5) In the embodiment described above, a plurality of second permanent magnets 10b and a plurality of top yokes 10t covering each of the plurality of second permanent magnets 10b are arranged in a row in one direction. However, the plurality of second permanent magnets 10b and the plurality of top yokes 10t covering each of the plurality of second permanent magnets 10b may be arranged in a grid on a plane. A grid arrangement of the second permanent magnets 10b means that a plurality of second permanent magnets 10b are arranged in a row in two directions that intersect each other on the plane. In this modification 5, a total of 16 second permanent magnets 10b are arranged in a grid of 4 rows x 4 columns in the X and Y directions.

[0131] Figure 17 illustrates the configuration of the permanent electromagnet 10. As will be described later using Figure 18, the multiple second permanent magnets 10b are arranged in a grid pattern on a plane extending in the X and Y directions, which intersect each other. The magnetization direction of each of the multiple second permanent magnets 10b is along the Z direction. The Z direction intersects both the X and Y directions. Figure 17 shows the configuration of the permanent electromagnet 10 as seen from the Y direction. That is, the configuration of the permanent electromagnet 10 in the X and Z directions is illustrated.

[0132] Figure 17 shows an example of the configuration of the permanent electromagnet 10 in the deactivated state. The magnetization directions of adjacent second permanent magnets 10b in the X and Y directions are opposite to each other. In the example shown in Figure 17, four second permanent magnets 10b are arranged from left to right along the X direction. The magnetization directions of adjacent second permanent magnets 10b are parallel to the Z direction and opposite to each other. Each of the four second permanent magnets 10b is covered by each of the multiple top yokes 10t. Therefore, the multiple top yokes 10t are arranged in a grid pattern together with the multiple second permanent magnets 10b on a plane extending in the X and Y directions that intersect each other.

[0133] Each of the multiple first permanent magnets 10a is positioned between two top yokes 10t adjacent to each other in the X and Y directions. In this embodiment, the magnetization direction of the first permanent magnet 10a positioned between two top yokes 10t adjacent to each other in the X direction is the X direction. The magnetization direction of the first permanent magnet 10a positioned between two top yokes 10t adjacent to each other in the Y direction is the Y direction. The first permanent magnets 10a may also be positioned to surround the outer circumference of the second permanent magnet 10b. In that case, the magnetization direction of the first permanent magnet 10a is the Z direction, which is parallel to the magnetization direction of the second permanent magnet 10b.

[0134] In the released state of the permanent electromagnet 10 shown in Figure 17, the magnetization direction of all the second permanent magnets 10b is oriented in the direction corresponding to the released state, similar to Figure 2. Therefore, all the magnetic flux B shown in Figure 17 is confined within the permanent electromagnet 10.

[0135] Figure 18 is a diagram illustrating the sequential energization control performed for each magnet group G on the second permanent magnets 10b arranged in a grid. When the permanent electromagnet 10 shown in Figure 17 is viewed from the Z direction, the permanent electromagnet 10 shown in Figure 18 is obtained. In the permanent electromagnet 10 shown in Figure 18, a total of 16 second permanent magnets 10b are arranged in a 4x4 grid in the X and Y directions.

[0136] Note that in Figure 18, the second permanent magnet 10b should not be visible because it is covered by the top yoke 10t. However, for the sake of explanation, Figure 18 shows the magnetic poles formed at the ends of the second permanent magnet 10b that are covered by the top yoke 10t when the permanent electromagnet 10 is released. As mentioned above, the magnetization directions of adjacent second permanent magnets 10b are opposite to each other. The multiple first permanent magnets 10a and the magnetic poles formed at both ends of each first permanent magnet 10a are also shown in Figure 18.

[0137] For the sake of explanation, Figure 18 shows the coordinates indicating the position of each second permanent magnet 10b in the X and Y directions. The position of each second permanent magnet 10b is represented by the coordinate values ​​(X, Y). Since a total of 16 second permanent magnets 10b are arranged in a 4x4 grid, both the X and Y coordinates take coordinate values ​​from 1 to 4.

[0138] In the permanent electromagnet 10 shown in Figure 18, four second permanent magnets 10b are positioned in the center of a 4x4 grid arrangement. The positions of the four second permanent magnets 10b positioned in the center of the grid arrangement are represented by the coordinate values ​​(2,3), (3,3), (3,2), and (2,2), respectively. Twelve second permanent magnets 10b are positioned at the edges of the 4x4 grid arrangement. The positions of the twelve second permanent magnets 10b positioned at the edges of the grid arrangement are represented by the coordinate values ​​(1,2), (1,3), (1,4), (2,4), (3,4), (4,4), (4,3), (4,2), (4,1), (3,1), (2,1), and (1,1), respectively.

[0139] The grouping unit 70 of the control device 40 divides the multiple second permanent magnets 10b into multiple magnet groups G. In this modified example 5, as in the embodiment described above, each magnet group G includes one second permanent magnet 10b. The energization control unit 72 of the control device 40 performs energization control by applying a voltage from the power supply 42 to the coil 10c wound around the outer circumference of each second permanent magnet 10b included in each magnet group G. The energization control unit 72 sequentially performs energization control for each magnet group G to set the magnetization direction of the second permanent magnet 10b to the direction corresponding to the attracted state.

[0140] The energization control unit 72 performs energization control sequentially for each magnet group G, and also performs energization stop control to stop the application of the applied voltage. In other words, the energization control unit 72 performs energization control and energization stop control after energization control for each magnet group G. As a result, the magnetization direction of each second permanent magnet 10b is reversed.

[0141] During the sequential energization control for each magnet group G, the magnet group G that has been energized and the next magnet group G to be energized are adjacent to each other. As described above, each magnet group G contains one second permanent magnet 10b. Therefore, the energization control is performed by successively moving through adjacent second permanent magnets 10b, and the magnetization direction of the adjacent second permanent magnets 10b is reversed in sequence.

[0142] The paths through which this energization control is performed by following the adjacent second permanent magnet 10b are, for example, paths Do and Di shown in Figure 18. Path Do is a path for sequentially performing energization control for each magnet group G, moving from the center to the edge of the grid-like arrangement of the second permanent magnets 10b described above. Path Di is a path for sequentially performing energization control for each magnet group G, moving from the edge to the center of the grid-like arrangement of the second permanent magnets 10b described above. In other words, paths Do and Di are paths moving in opposite directions.

[0143] Both paths Do and Di are paths that follow adjacent second permanent magnets 10b. Compared to paths that follow non-adjacent, spaced-out second permanent magnets 10b, using paths that follow adjacent second permanent magnets 10b to perform energization control can efficiently increase the magnetic flux B passing through the magnetic material W. Therefore, by performing energization control using paths that follow adjacent second permanent magnets 10b, such as paths Do and Di, the attractive force of the permanent electromagnet 10 in an attracted state is increased.

[0144] Furthermore, it is possible that the energization control of some of the second permanent magnets 10b of the permanent electromagnet 10 is not performed, but rather some of the second permanent magnets 10b are energized. For example, when the magnetic material W is small or light, the energization control of some of the second permanent magnets 10b may allow the permanent electromagnet 10 to have sufficient attractive force. Therefore, an example in which the energization control of four of the sixteen second permanent magnets 10b is performed will be described.

[0145] As described above, of the 16 second permanent magnets 10b arranged in a grid, 4 second permanent magnets 10b are placed in the center of the grid, and 12 second permanent magnets 10b are placed at the edges of the grid. As shown in Figure 18, there are 4 first permanent magnets 10a surrounding each second permanent magnet 10b placed in the center of the grid. There are 2 or 3 first permanent magnets 10a surrounding each second permanent magnet 10b placed at the edges of the grid. In other words, the number of first permanent magnets 10a surrounding each second permanent magnet 10b placed in the center of the grid is greater than the number of first permanent magnets 10a surrounding each second permanent magnet 10b placed at the edges of the grid.

[0146] As examples of controlling the energization of the four second permanent magnets 10b, a first control example is conceivable in which the energization of the four second permanent magnets 10b located in the center of the grid arrangement is controlled, and a second control example is conceivable in which the energization of the four second permanent magnets 10b located at the edges of the grid arrangement is controlled. The attractive force possessed by the permanent electromagnet 10 in the first control example is greater than the attractive force possessed by the permanent electromagnet 10 in the second control example. The reason for this is the difference in the number of first permanent magnets 10a surrounding each of the second permanent magnets 10b as described above.

[0147] As described above, in the permanent electromagnet 10 in the adsorbed state, the magnetic flux B passing through the magnetic material W includes both the magnetic flux B passing through the first permanent magnet 10a and the magnetic flux B passing through the second permanent magnet 10b. The magnetic flux B is greater for the second permanent magnet 10b, which is located in the center of the grid arrangement, than for the second permanent magnet 10b, which is located at the edge of the grid arrangement, because there are more first permanent magnets 10a surrounding the second permanent magnet 10b. Therefore, the adsorbent force of the permanent electromagnet 10 in the first control example is greater than the adsorbent force of the permanent electromagnet 10 in the second control example. In other words, paths Do and Di may be used interchangeably depending on the required adsorbent force.

[0148] With regard to the embodiments described above, the following additional information is disclosed.

[0149] (Note 1) The control device (40) of the present disclosure is a control device for controlling a permanent electromagnet (10) which has a plurality of first permanent magnets (10a) and a plurality of second permanent magnets (10b) and a coil (10c) wound around the outer circumference of each of the plurality of second permanent magnets, wherein the magnetization direction of the second permanent magnets around which the coils are wound is reversed according to the direction of the current that flows when a voltage is applied to the coils, thereby enabling switching between an adsorption state in which a magnetic material (W) can be attracted and a release state in which the adsorption state is released, and comprises a grouping unit (70) which divides the plurality of second permanent magnets into a plurality of magnet groups such that each magnet group (G) includes at least one of the second permanent magnets, and an energization control unit (72) which sequentially performs energization control for each magnet group by applying the applied voltage to the coil wound around the outer circumference of at least one of the second permanent magnets to change the magnetization direction of at least one of the second permanent magnets to the direction corresponding to the adsorption state. With this configuration, the attractive force of the permanent electromagnet is suppressed.

[0150] (Note 2) In the control device described in Note 1, the energization control unit may perform energization stop control to stop the application of the applied voltage after the energization control. With such a configuration, the power consumption of the permanent electromagnet can be reduced.

[0151] (Note 3) In the control device described in Note 2, the energizing control unit may, after performing the energizing control and energizing deactivation control for all of the plurality of magnet groups, sequentially perform the energizing control and energizing deactivation control again for at least some of the plurality of magnet groups, for each magnet group. With such a configuration, the attractive force of the permanent electromagnet can be adjusted.

[0152] (Note 4) The control device described in Note 2, wherein the plurality of second permanent magnets include the second permanent magnets of a first portion (P1) and the second permanent magnets of a second portion (P2) different from the first portion, and the energizing control unit sequentially performs the energizing control and the energizing deactivation control for each magnet group of the second permanent magnets of the first portion to cause the magnetic material to be attracted to the permanent electromagnet with a first attractive force (F1), and the energizing control unit further sequentially performs the energizing control and the energizing deactivation control for each magnet group of the second permanent magnets of the second portion to cause the magnetic material to be attracted to the permanent electromagnet with a second attractive force (F2) stronger than the first attractive force. With such a configuration, the stability of the attraction and transport of the magnetic material can be improved.

[0153] (Note 5) In the control device described in Note 2, the plurality of second permanent magnets include the second permanent magnet of a first part (Q1) and the second permanent magnet of a second part (Q2) different from the first part, and when the magnetization direction of the second permanent magnet of the first part is in the direction corresponding to the adsorption state and the magnetization direction of the second permanent magnet of the second part is in the direction corresponding to the release state, the energizing control unit may sequentially perform the energizing control and the energizing deactivation control for each magnet group with respect to the second permanent magnet of the second part to cause the magnetic material to be attracted to the permanent electromagnet, and when the magnetization direction of the second permanent magnet of the first part and the magnetization direction of the second permanent magnet of the second part are both in the direction corresponding to the adsorption state, the energizing control unit may detach the magnetic material from the permanent electromagnet by performing energizing control on the second permanent magnet of the second part to change the magnetization direction of the second permanent magnet to the direction corresponding to the release state. This configuration reduces the power consumption required to change the permanent electromagnet from an attracted state to a non-attracted state to the other.

[0154] (Note 6) A control device according to any one of Notes 1 to 5, wherein the magnet group may include at least two of the second permanent magnets whose magnetization directions are opposite to each other and adjacent to each other. With such a configuration, the permanent electromagnet can have an appropriate and stable attractive force.

[0155] (Note 7) In the control device described in any of Notes 1 to 6, the magnet group on which the energization control has been performed and the next magnet group on which the energization control will be performed may be adjacent to each other. With such a configuration, the attractive force of the permanent electromagnet in the attracted state is increased.

[0156] (Note 8) A control device according to any one of Notes 1 to 7, further comprising a identifying unit (74) that identifies the second permanent magnet corresponding to the position of the magnetic material in the released state of the permanent electromagnet, wherein the energizing control unit sequentially performs the energizing control for each magnet group with respect to the second permanent magnet identified by the identifying unit, thereby causing the magnetic material to be attracted to the permanent electromagnet. With such a configuration, the power consumption required to change the permanent electromagnet from an attracted state and a non-attracted state to the other can be reduced.

[0157] (Note 9) In the control device described in Note 1 or 2, if a plurality of the second permanent magnets are arranged in a grid pattern in the permanent electromagnet, the energizing control unit may sequentially perform the energizing control for each group of magnets, from the center and one edge of the grid pattern toward the other. With such a configuration, the attractive force of the permanent electromagnet when it is in an attractive state is increased.

[0158] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

Claims

1. A control device (40) for controlling a permanent electromagnet (10) having a plurality of first permanent magnets (10a) and a plurality of second permanent magnets (10b), and a coil (10c) wound around the outer circumference of each of the plurality of second permanent magnets, wherein the magnetization direction of the second permanent magnets around which the coils are wound is reversed according to the direction of the current flowing when a voltage is applied to the coils, thereby enabling switching between an adsorption state in which a magnetic material (W) can be attracted and a release state in which the adsorption state is released, comprising: a grouping unit (70) that groups the plurality of second permanent magnets into a plurality of magnet groups such that each magnet group (G) includes at least one of the second permanent magnets; and an energization control unit (72) that sequentially performs energization control for each magnet group by applying the applied voltage to the coil wound around the outer circumference of at least one of the second permanent magnets to change the magnetization direction of at least one of the second permanent magnets to the direction corresponding to the adsorption state.

2. A control device according to claim 1, wherein the energization control unit performs energization stop control to stop the application of the applied voltage after the energization control.

3. A control device according to claim 2, wherein the energizing control unit performs the energizing control and the energizing deactivation control for all of the plurality of magnet groups, and then sequentially performs the energizing control and the energizing deactivation control again for at least some of the plurality of magnet groups, for each magnet group.

4. A control device according to claim 2, wherein the plurality of second permanent magnets include a second permanent magnet of a first portion (P1) and a second permanent magnet of a second portion (P2) different from the first portion, the energizing control unit sequentially performs the energizing control and the energizing deactivation control on the second permanent magnet of the first portion for each magnet group, thereby causing the magnetic material to be attracted to the permanent electromagnet with a first attractive force (F1), and the energizing control unit further sequentially performs the energizing control and the energizing deactivation control on the second permanent magnet of the second portion for each magnet group, thereby causing the magnetic material to be attracted to the permanent electromagnet with a second attractive force (F2) stronger than the first attractive force.

5. A control device according to claim 2, wherein the plurality of second permanent magnets include a second permanent magnet of a first portion (Q1) and a second permanent magnet of a second portion (Q2) different from the first portion, and when the magnetization direction of the second permanent magnet of the first portion is in the direction corresponding to the adsorption state and the magnetization direction of the second permanent magnet of the second portion is in the direction corresponding to the release state, the energizing control unit sequentially performs the energizing control and the energizing deactivation control for each magnet group with respect to the second permanent magnet of the second portion, thereby causing the magnetic material to be attracted to the permanent electromagnet; when the magnetization direction of the second permanent magnet of the first portion and the magnetization direction of the second permanent magnet of the second portion are both in the direction corresponding to the adsorption state, the energizing control unit performs energizing control on the second permanent magnet of the second portion to change the magnetization direction of the second permanent magnet to the direction corresponding to the release state, thereby causing the magnetic material to be detached from the permanent electromagnet.

6. The control device according to claim 1, wherein the magnet group includes at least two second permanent magnets whose magnetization directions are opposite to each other and adjacent to each other.

7. A control device according to claim 1, wherein the magnet group on which the energization control has been performed and the next magnet group on which the energization control will be performed are adjacent to each other.

8. A control device according to claim 1, further comprising a identifying unit (74) for identifying the second permanent magnet corresponding to the position of the magnetic material in the released state of the permanent electromagnet, wherein the energizing control unit sequentially performs the energizing control for each magnet group with respect to the second permanent magnet identified by the identifying unit, thereby causing the magnetic material to be attracted to the permanent electromagnet.

9. A control device according to claim 1 or 2, wherein, in the permanent electromagnet, a plurality of the second permanent magnets are arranged in a grid pattern, the energizing control unit sequentially performs the energizing control for each group of magnets, from the center and one edge of the grid pattern toward the other.

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