Control method, computer program, and control device for controlling a robot arm

Abstract

To provide a technology capable of efficiently cooling a control device while suppressing increase in power consumption associated with overexcitation control of an electromagnetic brake.SOLUTION: A method includes the steps of: (a) performing overexcitation of an electromagnetic brake; (b) controlling a fan so that power consumption of the fan in cooling a control device is equal to a first power consumption in an overexcitation period during which overexcitation is performed; and (c) after the overexcitation period, controlling the fan so that the power consumption of the fan is equal to a second power consumption higher than the first power consumption.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control method, a computer program, and a control device for controlling a robot arm. [Background technology]

[0002] Patent Document 1 discloses a control device that includes a drive circuit that drives a robot's motor and a fan that cools the drive circuit. This control device is configured to cool the inside of the control device by driving a fan motor using electrical energy stored in a smoothing capacitor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-280076 Summary of the Invention [Problem to be solved by the invention]

[0004] Some robot arm motors are known to be equipped with overexcitation electromagnetic brakes, but when current is first applied to such motors, an overexcitation current is applied to the electromagnetic brake to release the brake, temporarily increasing the power consumption of the control device. However, in the past, there was a problem in that sufficient measures had not been taken to suppress the increase in power consumption associated with overexcitation of the electromagnetic brake while efficiently cooling the control device. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, there is provided a control method for a control device that controls a robot arm having a motor braked by an over-excitation type electromagnetic brake, the control method including: (a) over-exciting the electromagnetic brake; (b) controlling a fan that cools the control device so that the fan's power consumption becomes a first power consumption during an over-excitation period; and (c) controlling the fan so that the fan's power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period.

[0006] According to a second aspect of the present disclosure, there is provided a computer program for controlling a control device that controls a robot arm having a motor braked by an over-excitation type electromagnetic brake, the computer program causing a processor to execute the following processes: (a) performing over-excitation control of the electromagnetic brake; (b) controlling a fan that cools the control device so that its power consumption becomes a first power consumption during an over-excitation period; and (c) controlling the fan so that its power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period.

[0007] According to a third aspect of the present disclosure, there is provided a control device for controlling a robot arm having a motor braked by an over-excitation type electromagnetic brake. The control device includes a motor driver circuit that supplies power to the motor, a control power supply that supplies power to the electromagnetic brake, a fan that operates by receiving power from the control power supply and cools the control device, and a control unit that controls the motor driver circuit and the fan. The control unit executes the following processes: (a) a process for over-exciting the electromagnetic brake, (b) a process for controlling the fan so that its power consumption becomes a first power consumption during an over-excitation period, and (c) a process for controlling the fan so that its power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram showing a configuration of a robot system according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the internal configuration of a control device. [Figure 3] 4 is a timing chart showing a control operation in the embodiment. [Figure 4] 5A and 5B are explanatory diagrams showing state changes of a plurality of electromagnetic brakes in the embodiment. [Figure 5] 10 is a timing chart showing a control operation in a comparative example. [Figure 6] 10A and 10B are explanatory diagrams showing state changes of a plurality of electromagnetic brakes in another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 is an explanatory diagram showing an example of a robot system according to an embodiment. The robot system includes a robot 100, a control device 200 that controls the robot 100, and an information processing device 300. The information processing device 300 is, for example, a personal computer. A user can input instructions to operate the robot 100 using the information processing device 300. These instructions are supplied from the information processing device 300 to the control device 200, and the control device 200 controls the operation of the robot 100 in accordance with these instructions. The control device 200 may also receive instructions from an external device other than the information processing device 300.

[0010] The robot 100 includes a base 110 and a robot arm 120. An end effector 150 is attached to an arm end 122, which is the tip of the robot arm 120. The robot arm 120 is connected in sequence by six joints J1 to J6. Of these joints J1 to J6, three joints J2, J3, and J5 are bending joints, and the other three joints J1, J4, and J6 are torsion joints. Although a six-axis robot is exemplified in this embodiment, a robot having any robot arm mechanism having one or more joints can be used. Furthermore, although the robot 100 in this embodiment is a vertical multi-joint robot, a horizontal multi-joint robot may also be used.

[0011] FIG. 2 is a block diagram showing the internal configuration of the control device 200. In FIG. 2, communication lines are drawn with dotted lines and power lines are drawn with solid lines. Motors M1 to M6 and over-excitation type electromagnetic brakes B1 to B6 are provided at the multiple joints J1 to J6 of the robot arm 120, respectively. The over-excitation type is a method in which a large over-excitation current is applied when the power is turned on to switch from a brake-activated state to a brake-released state, and thereafter the brake-released state is maintained with a holding current that is smaller than the over-excitation current. When the power to the electromagnetic brake is stopped, the brake is activated.

[0012] The control device 200 includes a housing 210, a motor driver unit 220, a control power supply 230, a control unit 240 that controls other components within the control device 200, a cooling fan 250 that blows air toward the motor driver unit 220, and a ventilation fan 260 that exchanges air between the inside and outside of the housing 210. The motor driver unit 220 drives the motors M1 to M6 of the robot arm 120 by passing current through them. The motor driver unit 220 includes, for example, motor driver circuits 221 to 226 that are provided corresponding to each of the motors M1 to M6. Each of the motor driver circuits 221 to 226 includes a plurality of switching elements such as transistors or MOSFETs, and drives the motors M1 to M6 by controlling the current flowing through the motors M1 to M6 by switching the switching elements on and off. The control power supply 230 supplies power to the control unit 240, the cooling fan 250, and the ventilation fan 260, and also supplies power to the electromagnetic brakes B1 to B6 of the robot arm 120.

[0013] The housing 210 has a substantially rectangular parallelepiped shape and houses other components. The motor driver unit 220 includes a power semiconductor such as an IPM (Intelligent Power Module) and is a large heat source. The cooling fan 250 cools the motor driver unit 220 by blowing air onto the motor driver unit 220. The cooling fan 250 also functions as a circulator that circulates air within the housing 210. The ventilation fan 260 is attached to a wall of the housing 210 and cools the entire control device 200 by exchanging air between the inside and outside of the housing 210. In the example of FIG. 2, two ventilation fans 260 are provided, but three or more fans 260 may be provided, or only one fan may be provided. Both the cooling fan 250 and the ventilation fan 260 function as fans that cool the control device 200, and in particular, as fans that cool the motor driver unit 220. Note that one of the cooling fan 250 and the ventilation fan 260 may be omitted.

[0014] Electric power is supplied to the motors M1 to M6 of the robot arm 120 from the motor driver unit 220 via a first power line PL1. Electric power is supplied to the electromagnetic brakes B1 to B6 from the control power supply 230 via a second power line PL2. The second power line PL2 is connected to the electromagnetic brakes B1 to B6, for example, by a daisy chain connection. A bus connection may be used instead of a daisy chain connection. In either case, it is preferable that the multiple electromagnetic brakes B1 to B6 are connected by the second power line PL2, which is a common power supply line.

[0015] The electromagnetic brakes B1 to B6 are further connected to the control unit 240 via a communication line CL. The control unit 240 transmits operation commands to the electromagnetic brakes B1 to B6 via this communication line CL. Each of the electromagnetic brakes B1 to B6 may include a brake unit BM that brakes the joint and a brake driver circuit BD that drives the brake unit BM. The brake driver circuit BD controls the operation of the brake unit BM in accordance with the operation command provided by the control unit 240. Note that the brake driver circuit BD may be omitted, and the control unit 240 may directly control the brake unit BM.

[0016] The control unit 240 includes a processor 241 and a memory 242, and controls the other components in the control device 200 by executing a computer program stored in the memory. This computer program may be recorded on a non-transitory recording medium such as a hard disk or an optical disk. The functions of the control unit 240 may also be realized by a hardware circuit.

[0017] Fig. 3 is a timing chart showing the control operation in this embodiment. This control operation is executed by the control unit 240. Fig. 3 illustrates the following changes. Note that Fig. 3 illustrates the temperature Td for one of the motor driver circuits 221 to 226, but the temperature Td for each of the motor driver circuits would be plotted in a similar graph. (1) Excitation / de-excitation status of motors M1 to M6 (2) OFF / overexcitation / holding excitation status of electromagnetic brakes B1 to B6 (3) Cooling fan 250 ON / OFF status (4) ON / OFF status of ventilation fan 260 (5) Temperature Td of motor driver circuits 221 to 226 (6) Power consumption Wc of the control power supply 230

[0018] 3, the horizontal axis represents time, which is divided into the following five periods: The states of electromagnetic brakes B1 to B6, cooling fan 250, and ventilation fan 260 in each period are as follows: <Period P1> The period P1 is a period during which the motors M1 to M6 are in a non-excited state, that is, a state in which no power is supplied. The electromagnetic brakes B1 to B6 are in a de-energized braking state, that is, in a braking operation state. The cooling fan 250 is in the OFF state. The ventilation fan 260 is in the ON state. The ventilation fan 260 is turned on to prevent the control unit 240 from overheating. During this period P1, the control unit 240 monitors the state of the robot 100 and is on standby to receive external input. During period P1, the amount of heat generated within the control device 200 is less than during period P3 when the robot arm 120 is operating. Therefore, it is preferable to reduce the cooling capacity of the ventilation fan 260 to a level lower than during period P3 to reduce power consumption. Specifically, at least one of the multiple ventilation fans 260 may be turned on, or all ventilation fans 260 may be turned on with their rotation speeds lower than during period P3.

[0019] <Period P2> Period P2 is a period immediately after excitation of motors M1 to M6 is started, and is an overexcitation period during which electromagnetic brakes B1 to B6 are overexcited. The length of period P2 is, for example, about 0.4 seconds to about 1.2 seconds. After the electromagnetic brakes B1 to B6 are released from braking due to overexcitation, they are placed in a non-braking state where they are held excited, that is, in a brake-released state. The cooling fan 250 is maintained in the OFF state. The ventilation fan 260 is switched to the OFF state. The reason for turning off the cooling fan 250 and the ventilation fan 260 is to prevent an excessive increase in the power consumption of the control power supply 230 when a large over-excitation current is generated due to over-excitation of the electromagnetic brakes B1 to B6. During period P2, the cooling fan 250 and the ventilation fan 260 may all be turned off, or alternatively, their power consumption may be reduced compared to period P3. For example, only some of the cooling fan 250 and the ventilation fan 260 may be turned on, or their rotation speeds may be reduced. The power consumption of the cooling fan 250 and the ventilation fan 260 during period P2 is referred to as the "first power consumption." The first power consumption is preferably set to zero, but may also be a non-zero value.

[0020] At start timing t1 of period P2, when the control unit 240 receives an instruction from the information processing device 300 to operate the robot arm 120, the control unit 240 transmits, in response to this instruction, commands to excite the motors M1 to M6 to the motor driver circuits 221 to 226, and also transmits commands to over-excite the electromagnetic brakes B1 to B6, which are in a braking state. In the example of Fig. 3, the timings at which the electromagnetic brakes B1 to B6 are over-excited are offset from one another. This allows the power consumption due to over-excitation to be averaged out, thereby suppressing power peaks.

[0021] <Period P3> In period P3, the electromagnetic brakes B1 to B6 are in the brake release state, the motors M1 to M6 are excited, and the robot arm 120 is operable. All electromagnetic brakes B1 to B6 are in the released state. The cooling fan 250 is switched on. All ventilation fans 260 are switched on. As a method for issuing a command to start driving cooling fan 250 and ventilation fan 260 at start timing t2 of period P3, for example, the following two methods are conceivable. In the first method, control unit 240 measures time using a timer from start timing t1 of period P2, and when a predetermined time has elapsed, issues a drive command to cooling fan 250 and ventilation fan 260. In the second method, control unit 240 issues a drive command to cooling fan 250 and ventilation fan 260 almost simultaneously with sending a command to stop over-excitation to electromagnetic brake B1, which is over-excited last.

[0022] The power consumption of the cooling fan 250 and the ventilation fan 260 during the period P3 is referred to as the “second power consumption.” The second power consumption is greater than the first power consumption, which is the power consumption of the cooling fan 250 and the ventilation fan 260 during the period P2.

[0023] <Period P4> The period P4 is a period immediately after the motors M1 to M6 are switched to the non-excitation state at timing t3. The length of the period P4 is, for example, about 1 minute to about 5 minutes. All electromagnetic brakes B1 to B6 are switched to a de-energized brake operating state. The cooling fan 250 is maintained in an ON state. All ventilation fans 260 are kept ON. The reason why the cooling fan 250 and the ventilation fan 260 are maintained in the ON state is that the temperature Td of the motor driver circuits 221 to 226 is high immediately after the motors M1 to M6 are switched to the non-excitation state.

[0024] <Period P5> The period P5 is a period in which the motors M1 to M6 are in a non-excited state, that is, in which no power is supplied, and is the same state as the period P1 described above. The electromagnetic brakes B1 to B6 are in a de-energized braking state, that is, in a braking operation state. The cooling fan 250 is in the OFF state. The ventilation fan 260 is in the ON state. The start timing t4 of the period P5 is the time when the temperature Td of the motor driver circuits 221-226 has sufficiently dropped. This timing t4 may be determined by the control unit 240 using a temperature sensor to measure the temperature Td of the motor driver circuits 221-226, or may be determined by measuring the time from the start timing t3 of the period P4 using a timer. At the beginning of the period P5, the temperature Td of the motor driver circuits 221-226 rises slightly due to the cooling fan 250 being switched off, but the increase is small enough to not cause any problems.

[0025] The temperature Td of the motor driver circuits 221-226 reaches a maximum value during the period P3, but cooling is performed by the cooling fan 250 and the ventilation fan 260 to prevent the temperature Td from becoming excessively high. The power consumption Wc of the control power supply 230 reaches a maximum value Wc_max1 during the period P3, and is kept lower during the overexcitation period P2 than during the period P3. This point will be described in more detail below.

[0026] FIG. 4 is an explanatory diagram showing changes in the state of multiple electromagnetic brakes during period P2 in FIG. 3. As explained in FIG. 3, in this embodiment, the timings at which the electromagnetic brakes B1 to B6 are overexcited are staggered. More specifically, the individual overexcitation periods PP during which the individual electromagnetic brakes are overexcited are staggered so that they do not overlap. As a result, it is possible to prevent an increase in power consumption due to overlapping of the individual overexcitation periods PP of multiple electromagnetic brakes. Furthermore, in this example, the electromagnetic brakes are overexcited in order, starting with the electromagnetic brake B6 closest to the hand of the robot arm 120. That is, the electromagnetic brake B6 closest to the hand is overexcited first, and the electromagnetic brake B1 closest to the base 110 is overexcited last. This makes it possible to further equalize the power consumption due to overexcitation.

[0027] 5 is a timing chart showing the control operation in the comparative example. The only difference from the control operation in the embodiment shown in FIG. 3 is that cooling fan 250 and ventilation fan 260 are maintained in the on state throughout the entire period; the other operations are the same as those in FIG. 3. In this comparative example, cooling fan 250 and ventilation fan 260 are maintained in the on state even during overexcitation period P2, so that power consumption Wc of control power supply 230 is greater than during period P3, and power consumption Wc reaches a maximum value Wc_max2 during overexcitation period P2. This maximum value Wc_max2 is greater than the maximum value Wc_max1 in the embodiment shown in FIG. 3.

[0028] During the over-excitation period P2, the amount of heat generated by the motor driver circuits 221-226 is small, so even if the cooling fan 250 and the ventilation fan 260 are stopped, the thermal impact on the motor driver circuits 221-226 is small. Therefore, in the embodiment shown in Fig. 3, the cooling capacity of the cooling fan 250 and the ventilation fan 260 is reduced during the over-excitation period P2 compared to the period P3, thereby reducing power consumption. As a result, it is possible to achieve both a reduction in the power capacity of the control power supply 230 and cooling of the motor driver circuits 221-226.

[0029] As described above, in the above embodiment, during the overexcitation period P2, the power consumption of the fan that cools the control device 200 is set to the first power consumption, which is lower than the second power consumption during the period P3 after the overexcitation period P2, so that an excessive increase in power consumption during the overexcitation period P2 can be prevented. As a result, the control power supply 230 can be made smaller and less expensive.

[0030] In the above embodiment, the control device 200 controls the operation of multiple motors M1 to M6 and multiple electromagnetic brakes B1 to B6, but the number of motors and electromagnetic brakes to be controlled can be any number greater than or equal to one.

[0031] FIG. 6 is an explanatory diagram showing state changes of multiple electromagnetic brakes in another embodiment. The only difference from the embodiment shown in FIG. 4 is that the individual overexcitation periods PP of the electromagnetic brakes partially overlap. More specifically, like FIG. 4, the timings at which the electromagnetic brakes B1 to B6 are overexcited are shifted from one another. However, in FIG. 6, each individual overexcitation period PP is shifted by half from the adjacent individual overexcitation periods PP. This also prevents an increase in power consumption due to the overlap of all the individual overexcitation periods PP. Furthermore, in this example, the length of the total overexcitation period P2 is half the length of the overexcitation period P2 in FIG. 4, allowing the robot arm 120 to move more quickly.

[0032] In the various embodiments shown in Figures 4 and 6, the effect of suppressing the power consumption of the control power supply 230 during the overexcitation period P2 is achieved by both (i) a first feature in which the power consumption of the fan that cools the control device 200 is set to a first power consumption that is lower than a second power consumption in the period P3 after the overexcitation period P2, and (ii) a second feature in which the individual overexcitation periods PP are shifted relative to each other. Of these, the second feature may be omitted. In other words, the individual overexcitation periods PP for multiple electromagnetic brakes may be set to overlap. However, by employing both the first and second features, the effect of suppressing the power consumption of the control power supply 230 can be further enhanced.

[0033] Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0034] (1) According to a first aspect of the present disclosure, there is provided a control method for a control device that controls a robot arm having a motor braked by an over-excitation type electromagnetic brake, the control method including: (a) over-exciting the electromagnetic brake; (b) controlling a fan that cools the control device so that the fan's power consumption becomes a first power consumption during an over-excitation period; and (c) controlling the fan so that the fan's power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period. According to this control method, during the overexcitation period, the power consumption of the fan is set to the first power consumption that is lower than the second power consumption after the overexcitation period, thereby preventing the power consumption from increasing excessively during the overexcitation period.

[0035] (2) In the above control method, the robot arm may have a plurality of the electromagnetic brakes and a plurality of the motors, and the electromagnetic brakes may be overexcited at different times. According to this control method, power consumption due to overexcitation can be leveled out, thereby suppressing power peaks.

[0036] (3) In the above control method, the plurality of electromagnetic brakes may be connected by a common power supply line, and the plurality of electromagnetic brakes may be over-excited in order starting from the electromagnetic brake closest to the tip of the robot arm. According to this control method, power consumption due to overexcitation can be further leveled out, thereby suppressing power peaks.

[0037] (4) In the above control method, the fan may include a ventilation fan that exchanges air between the inside and outside of the control device, and the ventilation fan may start operating after the control device receives an instruction from the outside to operate the robot arm. This control method allows the ventilation fan to operate when ventilation is required, while suppressing power peaks.

[0038] (5) In the above control method, the control device may have a plurality of ventilation fans, and in the step (b), the control device may stop at least some of the plurality of ventilation fans. This control method can further reduce the power peak.

[0039] (6) In the above control method, in the step (b), all of the plurality of ventilation fans may be stopped. This control method can further reduce the power peak.

[0040] (7) In the above control method, the control device may have a motor driver circuit that supplies power to the motor, and the fan may include a cooling fan that blows air onto the motor driver circuit, and in step (b), the cooling fan may be stopped. According to this control method, even if the cooling fan is stopped during the overexcitation period, the temperature of the motor driver circuit does not rise excessively, so that the power peak can be suppressed.

[0041] (8) According to a second aspect of the present disclosure, there is provided a computer program for controlling a control device that controls a robot arm having a motor braked by an over-excitation type electromagnetic brake. The computer program causes a processor to execute the following processes: (a) switching from a brake-activated state to a brake-released state by over-exciting the electromagnetic brake; (b) controlling a fan that cools the control device so that its power consumption becomes a first power consumption during an over-excitation period; and (c) controlling the fan so that its power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period.

[0042] (9) According to a third aspect of the present disclosure, there is provided a control device for controlling a robot arm having a motor braked by an over-excitation type electromagnetic brake. The control device includes a motor driver circuit that supplies power to the motor, a control power supply that supplies power to the electromagnetic brake, a fan that operates by receiving power from the control power supply and cools the control device, and a control unit that controls the motor driver circuit and the fan. The control unit executes the following processes: (a) a process for over-exciting the electromagnetic brake, (b) a process for controlling the fan so that its power consumption becomes a first power consumption during an over-excitation period, and (c) a process for controlling the fan so that its power consumption becomes a second power consumption higher than the first power consumption after the over-excitation period.

[0043] The present disclosure may be realized in various forms other than those described above, such as a robot system including a robot and a control device, a computer program for implementing the functions of the control device, or a non-transitory storage medium on which the computer program is recorded. [Explanation of symbols]

[0044] 100... robot, 110... base, 120... robot arm, 122... arm end, 150... end effector, 200... control device, 210... housing, 220... motor driver unit, 221 to 226... motor driver circuit, 230... control power supply, 240... control unit, 241... processor, 242... memory, 250... cooling fan, 260... ventilation fan, 300... information processing device

Claims

1. Control a robot arm with a motor that is braked by an overexcitation type electromagnetic brake. and a control device including a motor driver circuit for supplying power to the motor.

1. A method comprising: (a) over-exciting the electromagnetic brake; (b) Power consumption of a fan that cools the control device during an overexcitation period in which the overexcitation is performed. controlling the fan so that the first power consumption is equal to the first power consumption; (c) after the overexcitation period, a second power consumption of the fan is higher than the first power consumption; controlling the fan so as to consume less power; A control method comprising:

2. 2. The control method according to claim 1, The robot arm has a plurality of the electromagnetic brakes and a plurality of the motors. 、 A control method in which the timing of over-exciting each electromagnetic brake is staggered.

3. 3. The control method according to claim 2, the plurality of electromagnetic brakes are connected by a common power line, The plurality of electromagnetic brakes are arranged in a range from the electromagnetic brake closest to the tip of the robot arm A control method in which the motor is over-excited in sequence.

4. The control method according to any one of claims 1 to 3, the fan includes a ventilation fan that exchanges air between the inside and outside of the control device, The ventilation fan is configured to operate the robot arm when the control device receives an instruction from the outside. and starting operation before receiving the overexcitation signal or after the overexcitation period.

5. 5. The control method according to claim 4, The control device has a plurality of the ventilation fans, In the step (b), at least some of the ventilation fans are stopped. Control method.

6. 6. The control method according to claim 5, In the step (b), all of the plurality of ventilation fans are stopped. 。

7. The control method according to any one of claims 1 to 6, the control device includes a motor driver circuit that supplies power to the motor; the fan includes a cooling fan that blows air onto the motor driver circuit; In the step (b), the cooling fan is stopped.

8. Control a robot arm with a motor that is braked by an overexcitation type electromagnetic brake. and a control device including a motor driver circuit for supplying power to the motor. A computer program for performing the following: (a) a process of over-exciting the electromagnetic brake; (b) Power consumption of a fan that cools the control device during an overexcitation period in which the overexcitation is performed. a process of controlling the fan so that the first power consumption is equal to the first power consumption; (c) after the overexcitation period, a second power consumption of the fan is higher than the first power consumption; a process of controlling the fan so as to consume less power; A computer program that causes a processor to execute the following:

9. Controlling a robot arm with a motor braked by an overexcitation type electromagnetic brake A control device comprising: a motor driver circuit that supplies power to the motor; a control power supply that supplies power to the electromagnetic brake; a fan that operates by receiving power from the control power supply and cools the control device; a control unit that controls the motor driver circuit and the fan; Equipped with The control unit (a) a process of over-exciting the electromagnetic brake; (b) during an overexcitation period in which the overexcitation is performed, the power consumption of the fan becomes a first power consumption; and controlling the fan so as to (c) after the overexcitation period, a second power consumption of the fan is higher than the first power consumption; a process of controlling the fan so as to consume less power; A control device that executes the above.

Images