JP7645378B2 - Power Supply - Google Patents

Description

The present disclosure relates to a power supply device that provides power to a motor that operates a robot arm.

Patent document 1 describes a power supply control device that can suppress the occurrence of inrush current when the power switch is turned on in a bypass capacitor connected in parallel to a load to which a DC voltage is supplied from a DC power supply via a power switch.

Patent No. 6467902

However, there are times when instantaneous movements are required in robots such as articulated robots and SCARA robots that are equipped with amplifier boards that variably control the voltage applied to the motors that operate the robot arms. To achieve such instantaneous movements, it may be desirable to increase the capacitance by connecting a large-capacity electrolytic capacitor in parallel to the power supply line, but due to size restrictions on the amplifier board or height restrictions on the installation location, it may not be possible to install electrolytic capacitors that are large enough to obtain the required capacitance.

However, since Patent Document 1 does not mention increasing capacitance, the above problem cannot be solved even if the power supply control device described in Patent Document 1 is used.

The present disclosure aims to provide a power supply device that makes it possible to easily increase the capacitance of a power line when it is desired to increase the capacitance.

In order to achieve the above-mentioned object, the power supply device disclosed herein includes a power supply board that supplies power to a motor that operates a robot arm, one or more expanded capacitance boards that are connected in parallel to the power line of the power supply board and increase the capacitance of the power line, a capacitor that is provided on the expanded capacitance board and increases the capacitance of the power line, an inrush current suppression mechanism that is provided on the expanded capacitance board and suppresses excessive inrush current from flowing into the capacitor from the power line when the expanded capacitance board is connected to the power line, and a first switching mechanism that switches on the connection of the expanded capacitance board to the power line when the voltage of the power line rises to or above a first predetermined value, and the expanded capacitance board further includes a second switching mechanism that switches off the inrush current suppression mechanism's suppression of inrush current when the voltage of the power line rises to or above a second predetermined value after the first switching mechanism switches on the connection of the expanded capacitance board to the power line .

According to the present disclosure, it is possible to easily increase the capacitance of a power line when desired.

FIG. 2 is a perspective view showing an outline of the configuration of a component mounter. FIG. 2 is a block diagram showing electrical connections of a control device. FIG. 2 is an electric circuit diagram showing a circuit configuration of a power supply device. FIG. 1 is an electrical circuit diagram used to simulate the operation of an inrush current prevention resistor. FIG. 5 is a diagram showing a simulation result of the electric circuit of FIG. 4. FIG. 5 is an electric circuit diagram in which an expansion capacitance is added to the electric circuit of FIG. 4. FIG. 7 is a diagram showing a simulation result using the electric circuit of FIG. 6. FIG. 13 is a diagram showing a connection manner for connecting an expansion capacity to a power supply line.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. Fig. 1 shows an outline of the configuration of the component mounter 10, and Fig. 2 shows the electrical connection relationship of the control device 60. Note that the up-down direction in Fig. 1 is the Z-axis direction.

The component mounting machine 10 of this embodiment comprises a vertical articulated robot 40, a Z-axis direction moving device 50, a nozzle 53, and a control device 60 (see Figure 2).

The vertical articulated robot 40 has four robot movable parts (shoulder 42, lower arm 43, upper arm 44, and wrist 45). The four robot movable parts are connected to the top of a cylindrical base part 41. Specifically, the shoulder 42 is connected to the upper surface of the base part 41 via a first joint 41j so as to be rotatable around the vertical axis 41a. The lower end of the lower arm 43 is connected to the shoulder 42 via a second joint 42j so as to be rotatable around the horizontal axis 42a. The base end of the upper arm 44 is connected to the upper end of the lower arm 43 via a third joint 43j so as to be rotatable around the horizontal axis 43a. The wrist 45 is connected to the tip of the upper arm 44 via a fourth joint 44j so as to be rotatable around an axis 44a extending in a direction perpendicular to the longitudinal direction of the upper arm 44. The Z-axis direction moving device 50 is connected to the wrist 45 so as to be rotatable around the axis 44a together with the wrist 45. The first joint 41j incorporates a first motor 41m that rotationally drives the shoulder 41, and the second joint 42j incorporates a second motor 42m that rotationally drives the lower arm 43. The third joint 43j incorporates a third motor 43m that rotationally drives the upper arm 44, and the fourth joint 44j incorporates a fourth motor 44m that rotationally drives the wrist 45. The first to fourth motors 41m to 44m are equipped with first to fourth encoders 41e to 44e (see FIG. 2), respectively. In this embodiment, servo motors are used as the motors, and rotary encoders are used as the encoders.

The Z-axis direction moving device 50 comprises a device body 51 and a Z-axis slider 52. The device body 51 is an approximately rectangular parallelepiped member here, and is fixed to the wrist 45. Therefore, the device body 51 can rotate around the axis 44a. The Z-axis slider 52 is attached to the front surface of the device body 51 so as to be able to slide along the longitudinal direction of the device body 51. This Z-axis slider 52 is driven by a Z-axis drive device 54 (e.g., a linear motor or a ball screw mechanism) attached to the device body 51.

The nozzle 53 is provided on the underside of the suction head 55. The nozzle 53 picks up and releases components by adjusting the pressure at the tip of the nozzle. The nozzle 53 is attached to the suction head 55 so that it can be detached and rotated about its axis. The suction head 55 is fixed to the Z-axis slider 52. Therefore, the nozzle 53 slides together with the suction head 55 and the Z-axis slider 52.

The control device 60 is a device that controls the operation of the vertical articulated robot 40 and the operation of the Z-axis direction moving device 50. As shown in FIG. 2, the control device 60 includes a CPU 61, a ROM 62, a HDD 63, and a RAM 64. The first to fourth drive circuits 41d to 44d, the first to fourth position detection circuits 41p to 44p, the Z-axis drive circuit 54d, the Z-axis position detection circuit 54p, the input device 70, and the output device 72 are connected to the CPU 61. The first to fourth drive circuits 41d to 44d and the Z-axis drive circuit 54d are provided corresponding to the first to fourth motors 41m to 44m and the Z-axis drive device 54, respectively. The first to fourth drive circuits 41d to 44d and the Z-axis drive circuit 54d output electric signals based on command signals from the CPU 61 to the corresponding first to fourth motors 41m to 44m and the Z-axis drive device 54, respectively. The first to fourth position detection circuits 41p to 44p are provided to detect the positions of the robot movable parts and correspond to the first to fourth encoders 41e to 44e, respectively. The Z-axis position detection circuit 54p is provided to detect the Z-axis position of the nozzle 53 and corresponds to the Z-axis encoder 54e. The first to fourth position detection circuits 41p to 44p detect the angular positions of the first to fourth motors 41m to 44m based on the detection signals input from the corresponding first to fourth encoders 41e to 44e and output the detected angular positions to the CPU 61. The Z-axis position detection circuit 54p detects the Z-axis position of the nozzle 53 based on the detection signal input from the Z-axis encoder 54e and outputs the detected angular positions to the CPU 61. The input device 70 is a keyboard and a mouse through which the operator performs input operations. The output device 72 is a display that displays various data as visual information such as images.

Figure 3 shows an outline of the electrical circuit of the power supply control device 100. The power supply control device 100 is mainly composed of an AC power supply (sometimes abbreviated as "power supply") V, a power supply board 110, and an expansion capacitance board 120. The power supply board 110 supplies a power supply DCLINK to the motor drive circuit 112 etc. based on the power supply V. The expansion capacitance board 120 expands the capacitance of the power supply line DCLINK of the power supply board 110.

The power supply board 110 is provided with a switch S1 that functions as a safety breaker that turns on/off the supply of the power supply V to the power supply board 110 via the full-wave rectifier circuit 111. The input terminal of the full-wave rectifier circuit 111 is connected to the output terminal of the switch S1. The full-wave rectifier circuit 111 converts the AC voltage of the power supply V into a DC voltage. One end of the inrush current suppression resistor R1 is connected to the output terminal of the full-wave rectifier circuit 111, and the other end of the inrush current suppression resistor R1 is connected to one end of the positive electrode side of each of the electrolytic capacitors C1 and C2. The other end of the negative electrode side of each of the electrolytic capacitors C1 and C2 is grounded. In addition, a switch S2 is connected in parallel with the inrush current suppression resistor R1. Furthermore, the input terminal of the motor drive circuit 112 is connected to one end of the positive electrode side of each of the electrolytic capacitors C1 and C2. The motor drive circuit 112 includes the first to fourth drive circuits 41d to 44d and the Z-axis drive circuit 54d. A motor 200 is connected to the output terminal of the motor drive circuit 112. The motor 200 includes the first to fourth motors 41m to 44m and the Z-axis drive device 54. In this manner, the power supply board 110 has electronic components mounted thereon from the switch S1 to the motor drive circuit 112.

The switch S2 switches between OFF and ON to supply the DC current (sometimes abbreviated as "current") supplied from the power source V through the full-wave rectifier circuit 111 via the inrush current suppression resistor R1 to the electrolytic capacitors C1 and C2, or to bypass the inrush current suppression resistor R1 and directly to the electrolytic capacitors C1 and C2, by turning the switch S1 ON and OFF. The switch S2 is configured, for example, as a relay that automatically switches from OFF to ON when the voltage value of the power source line DCLINK rises above a predetermined voltage value (<output voltage value from the full-wave rectifier circuit 111). The predetermined voltage value, that is, the switching threshold value, can be set to any value by setting. When the switch S1 is switched from OFF to ON and the supply of current from the power source V to the power supply board 110 via the full-wave rectifier circuit 111 begins, no charge is stored in the electrolytic capacitors C1 and C2, so the switch S2 is in the OFF state. After that, electric charges are accumulated in the electrolytic capacitors C1 and C2 as time passes, and when the voltage value of the power supply line DCLINK becomes equal to or higher than the switching threshold value, the switch S2 automatically switches from off to on. As a result, the current supplied from the full-wave rectifier circuit 111 bypasses the inrush current suppression resistor R1 and flows directly into the electrolytic capacitors C1 and C2 via the switch S2. After that, the electrolytic capacitors C1 and C2 are fully charged, and the voltage value of the power supply line DCLINK rises to the output voltage value from the full-wave rectifier circuit 111.

In this way, in the initial stage when no charge has accumulated in the electrolytic capacitors C1 and C2, the current from the full-wave rectifier circuit 111 is passed through the inrush current suppression resistor R1 to the electrolytic capacitors C1 and C2 in order to limit the current that flows suddenly through the electrolytic capacitors C1 and C2, i.e., the excessive inrush current, by the inrush current suppression resistor R1. If an excessive inrush current occurs, there is a risk that the copper foil pattern of the board will burn out or electronic components will be damaged, so the inrush current suppression resistor R1 suppresses the occurrence of an excessive inrush current. However, if the current from the full-wave rectifier circuit 111 is constantly passed through the inrush current suppression resistor R1, a voltage drop and unnecessary heat generation will occur in the power supply line DCLINK, so when there is no risk of an excessive inrush current occurring, that is, when the voltage value of the power supply line DCLINK rises above a predetermined voltage value, the switch S2 is switched from off to on to bypass the inrush current suppression resistor R1. In addition, the specified voltage value cannot be determined universally because it varies depending on the output voltage value from the full-wave rectifier circuit 111 and the electronic components used, etc., but a voltage value lower than the output voltage value from the full-wave rectifier circuit 111 is determined each time through experience or experiment.

In addition, the expansion capacitance board 120 is connected in parallel to the power supply line DCLINK of the power supply board 110 via a connection line 130. The expansion capacitance board 120 includes switches S3 and S4, an inrush current suppression resistor R2, and electrolytic capacitors C3 to C5. Note that the connection relationship of the electronic components S4, R2, and C3 to C5 provided on the expansion capacitance board 120 is substantially the same as the connection relationship of the electronic components S2, R1, C1, and C2 provided on the power supply board 110, and therefore a description thereof will be omitted.

The electrolytic capacitors C3 to C5 are capacitors for increasing the capacitance of the power supply line DCLINK. The switch S3 (an example of a "first switching mechanism") switches the actual connection of the expansion capacity board 120 to the power supply board 110 on and off. Like the switch S2, the switch S3 is also configured by, for example, a relay that automatically switches from off to on when the voltage value of the power supply line DCLINK rises above a predetermined voltage value (<the output voltage value from the full-wave rectifier circuit 111). However, the switch S3 differs from the switch S2 in that the predetermined voltage value, that is, the switching threshold value, may not be the same. The switching threshold value of the switch S3 is hereinafter referred to as the "first predetermined value". The inrush current suppression resistor R2 (an example of a "inrush current suppression mechanism"), like the inrush current suppression resistor R1, is intended to suppress excessive inrush current, that is, excessive inrush current generated when the current from the power supply line DCLINK flows into the electrolytic capacitors C3 to C5 that do not have accumulated charge. The switch S4 (an example of a "second switching mechanism") switches between supplying the current supplied from the power supply line DCLINK via the inrush current suppression resistor R2 to the electrolytic capacitors C3 to C5 or bypassing the inrush current suppression resistor R2 and directly supplying the current to the electrolytic capacitors C3 to C5, similarly to the switch S2. The switch S4, like the switch S2, is also configured by, for example, a relay that automatically switches from off to on when the voltage value of the power supply line DCLINK rises above a predetermined voltage value (<the output voltage value from the full-wave rectifier circuit 111). However, the switch S4 differs from the switches S2 and S3 in that the predetermined voltage value, that is, the switching threshold value, may not be the same. The switching threshold value of the switch S4 is hereinafter referred to as the "second predetermined value".

Figure 4 is an electrical circuit diagram used in a simulation to show the effect of the inrush current suppression resistor R1 on the power supply board 110. In Figure 4, the same electronic components as those in Figure 3 are given the same reference numerals. However, the power supply V1 indicates a DC power supply, and in Figure 3, it corresponds to a combination of the AC power supply V and the full-wave rectifier circuit 111. As can be seen by comparing the electrical circuit diagram in Figure 4 with the electrical circuit diagram in Figure 3, a resistor R11 has been added to the electronic components on the power supply board 110 in Figure 4. The resistor R11 is used for convenience to stabilize the output waveform obtained by the simulation, and can be ignored in practice. The values displayed near each electronic component indicate the specifications of the electronic component.

Figure 5 shows the results of a simulation using the electric circuit of Figure 4. In the simulation results of Figure 5, 0.5 seconds later, switch S1 is switched from off to on, and when the voltage value of the power supply line DCLINK reaches 250V, switch S2 is switched from off to on. The point in time when this switching occurs is approximately 1 second, approximately 0.5 seconds having passed since switch S1 was switched from off to on.

Figure 5(a) shows the change in voltage value G1 of the power supply line DCLINK. In Figure 5(b), the solid line G2 shows the change in the current value flowing through the inrush current suppression resistor R1, and the dashed line G3 shows the change in the current value flowing through the electrolytic capacitor C1. In Figure 5(c), the solid line G4 shows the change in the power consumed by the inrush current suppression resistor R1, and the dashed line G5 shows the change in the power supplied to the electrolytic capacitor C1.

From 0.5 seconds to approximately 1 second, the current from the power source V1 is supplied to the electrolytic capacitor C1 via the inrush current suppression resistor R1, so that, as shown by the solid line G2 in FIG. 5(b), the peak value of the current flowing through the inrush current suppression resistor R1 is approximately 3.0 A, and the peak value of the current supplied to the electrolytic capacitor C1 is also approximately 1.5 A. The reason why the peak value of the current supplied to the electrolytic capacitor C1 is 1/2 of the peak value of the current flowing through the inrush current suppression resistor R1 is because the current flowing through the inrush current suppression resistor R1 is equally divided between the electrolytic capacitors C1 and C2. If the current from the power source V1 is supplied directly to the electrolytic capacitor C1 without passing through the inrush current suppression resistor R1, an excessive inrush current of approximately 1400 A will instantaneously flow through the electrolytic capacitor C1. This will cause the risk of damage to the electronic components on the power supply board 110 described above and the burning of the copper foil pattern. By passing the current through the inrush current suppression resistor R1 in this way, the occurrence of an excessive inrush current is suppressed. Meanwhile, from 0.5 seconds to approximately 1 second, the inrush current suppression resistor R1 consumes power as shown by the solid line G4 in Fig. 5(c). This power consumption causes the inrush current suppression resistor R1 to heat up, so it is necessary to be careful about the durability of the current suppression resistor R1 due to this heat generation.

Figure 6 is an electrical circuit diagram used in a simulation to compare the effect of the inrush current suppression resistor R1 in the power supply board 110 with the effect of the inrush current suppression resistor R2 in the power supply control device 100 in which the expansion capacitance board 120 is connected to the power supply board 110. In Figure 6, the same electronic components as those in Figure 3 are given the same reference numerals. However, the electronic components on the power supply board 110 in Figure 6 are given reference numerals with the addition of "b" to the reference numerals given to the electronic components on the power supply board 110 in Figure 4. This is done simply to distinguish whether the electronic components on the power supply board 110 are electronic components on the power supply board 110 to which the expansion capacitance board 120 is connected or electronic components on the power supply board 110 to which the expansion capacitance board 120 is not connected.

Figure 7 shows the results of a simulation using the electric circuit of Figure 6. In the simulation results of Figure 7, as in the simulation results of Figure 5, after 0.5 seconds, switches S1 and S1b are switched from off to on, and when the voltage value of the power supply lines DCLINK and DCLINKB reaches 250V, switches S2 and S2b are switched from off to on. The switching occurs at a point of approximately 1 second, approximately 0.5 seconds after switches S1 and S1b are switched from off to on. In addition, switch S3 is switched from off to on when the voltage value of the power supply line DCLINK reaches 250V. Note that graphs in Figure 7 that correspond to those in Figure 5 are given the same reference numerals.

In FIG. 7(a), the solid line G1 indicates the change in the voltage value of the power supply line DCLINK, and the dashed line G11 indicates the change in the voltage value of the power supply line exDCLINK. In FIG. 7(b), the solid line G2 indicates the change in the current value flowing through the inrush current suppression resistor R1b, and the dashed line G3 indicates the change in the current value flowing through the electrolytic capacitor C1b. In FIG. 7(c), the solid line G21 indicates the change in the current value flowing through the inrush current suppression resistor R2, and the dashed line G31 indicates the change in the current value flowing through the electrolytic capacitor C3. In FIG. 7(d), the solid line G4 indicates the change in the power consumed by the inrush current suppression resistor R1b, and the dashed line G41 indicates the change in the power consumed by the inrush current suppression resistor R2. In FIG. 7(e), the solid line G5 indicates the change in the power supplied to the electrolytic capacitor C1b, and the dashed line G51 indicates the change in the power supplied to the electrolytic capacitor C3.

From about 1 second to about 2.8 seconds, the current from the power supply line DCLINK is supplied to the electrolytic capacitor C3 via the inrush current suppression resistor R2, so that excessive inrush current is suppressed, as shown by the solid line G21 in FIG. 7(c). Also, from about 1 second to about 2.8 seconds, the peak value of the power consumed by the inrush current suppression resistor R2 is lower than the peak value of the power consumed by the inrush current suppression resistor R1 from 0.5 seconds to about 1 second. This is because the value of the inrush current suppression resistor R2 is larger than the value of the inrush current suppression resistor R1, so the current passing through the inrush current suppression resistor R2 is more limited. Therefore, the temperature rise due to heat generation of the inrush current suppression resistor R2 is lower than the temperature rise due to heat generation of the inrush current suppression resistor R1. As a result, when the current suppression resistors R1 and R2 have the same configuration, the durability due to heat generation of the inrush current suppression resistor R2 is improved compared to that of the current suppression resistor R1. By further restricting the current passing through the inrush current suppression resistor R2 in this way, the inrush current supplied to the electrolytic capacitors C3 to C5 is further restricted, so that the amount of charge supplied per unit time to the electrolytic capacitors C3 to C5 is reduced, and as a result, as shown by the dashed line G11 in Fig. 7(a), the voltage value of the power supply line exDCLINK rises more slowly. In other words, the time it takes for the power supply control device 100 to enter standby after the switch S1 is switched from off to on is delayed. For this reason, it is desirable to determine the resistance value of the inrush current suppression resistor R2 by taking into consideration the durability of the inrush current suppression resistor R2, the time it takes for the power supply control device 100 to enter standby, and the like.

The second predetermined value of switch S4 is the voltage value of the power supply line exDCLINK when it rises to a value at which there is no risk of excessive inrush current flowing into electrolytic capacitors C3 to C5. This second predetermined value, like the switching threshold of switch S2, cannot be determined universally. In other words, while the voltage value of the power supply line exDCLINK is below the second predetermined value, the current from the power supply line DCLINK is supplied to electrolytic capacitors C3 to C5 via inrush current suppression resistor R2, and the inrush current is limited by the inrush current suppression resistor R2. However, when the voltage value of the power supply line exDCLINK becomes equal to or greater than the second predetermined value, the current from the power supply line DCLINK is supplied directly to electrolytic capacitors C3 to C5, bypassing the inrush current suppression resistor R2. At this time, the current value of the inrush current is determined according to the magnitude of the potential difference between the power supply line DCLINK and the power supply line exDCLINK, and whether or not the current value becomes excessive is determined according to the specifications of the electronic components subsequent to the electrolytic capacitors C3 to C5.

As described above, in the power supply control device 100 of this embodiment, the capacitance of the power supply line DCLINK can be increased while suppressing inrush current simply by connecting the expansion capacitance board 120 to the power supply board 110. In addition, the expansion capacitance board 120 monitors the voltage value of the power supply line DCLINK by itself and automatically switches the connection to the power supply board 110 on and off, so there is no need to send a switching signal from the outside, which reduces the manufacturing cost of the entire power supply board 110. In addition, when the capacitance is increased, the regenerative energy generated on the power supply line DCLINK when the robot 40 slows down or suddenly stops during operation can be recovered as recyclable capacitance instead of being consumed as heat energy, making it an environmentally friendly device.

Figure 8 shows a connection manner for connecting an expansion capacity to a power supply line. Figure 8(a) shows a manner in which the expansion capacity board 120 is connected when multiple motors are controlled by one power supply board 110. Figure 8(b) shows an example of a manner in which the expansion capacity board 120 is connected when multiple motors are controlled by multiple power supply boards 110a to 110c. The connection manner in Figure 8(a) is the same as the connection manner shown in Figure 3, so further explanation is omitted.

When the power supply boards 110a to 110c shown in FIG. 8(b) are assembled inside the joints 41j to 43j of the vertical articulated robot 40, for example, the power supply boards 110a to 110c are connected in a daisy chain, but the further the control axis is from the main body base, the more likely it is that the power supply will be delayed or the power supply line DCLINK will shake. If only the hand is operated suddenly, or if it is desired to install an electrolytic capacitor to stabilize the power supply line DCLINK using the components of the power supply boards 110a to 110c but it is not possible to do so, as shown in FIG. 8(b), the power supply boards 110a to 110c can be relayed in a manner that connects the expansion capacity board 120 between the power supply boards 110a to 110c, thereby increasing the capacitance of the power supply line DCLINK and stabilizing the power supply line DCLINK. The inside of the joints 41j to 43j is often filled with the power supply boards 110a to 110c and there is no free space, so if the expansion capacity board 120 is installed in the hollow part of the robot arm, the space can be used efficiently.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. In the above embodiment, an example in which one expansion capacitance board 120 is connected to the power supply board 110 is described, but this is not limited thereto, and multiple expansion capacitance boards 120 may be connected to the power supply board 110.

40...vertical articulated robot, 41m to 44m...motors, 60...control device, 100...power supply control device, 110...power supply board, 111...full-wave rectifier circuit, 112...motor drive circuit, 120...expansion capacity board, 130...connection line, 200...motor, V...AC power supply, DCLINK...motor power line, S1 to S4...switches, R1, R2...inrush current suppression resistors, C1 to C5...electrolytic capacitors.

Claims (3)

a power supply board that supplies power to a motor that operates the robot arm;
one or more expansion capacitance boards connected in parallel to the power lines of the power supply board to increase the capacitance of the power lines;
a capacitor provided on the expansion capacitance substrate for increasing a capacitance of the power supply line;
an inrush current suppression mechanism provided on the expansion capacitance substrate, the inrush current suppression mechanism suppressing an excessive inrush current from flowing into the capacitor from the power supply line when the expansion capacitance substrate is connected to the power supply line;
a first switching mechanism that switches on a connection of the expansion capacitance substrate to the power supply line when a voltage of the power supply line rises to or exceeds a first predetermined value;
Equipped with
The expansion capacitance substrate further comprises:
a second switching mechanism that switches off the inrush current suppression mechanism's suppression of the inrush current when a voltage of the power supply line rises to a second predetermined value or higher after the first switching mechanism switches on the connection of the expansion capacitance board to the power supply line.
A power supply device comprising : When the robot arm includes a plurality of robot arms, the plurality of robot arms are operated by a plurality of motors, and power is supplied to the plurality of motors by a plurality of power supply boards,
The expansion capacitance board is connected between the plurality of power supply boards.
2. The power supply device according to claim 1 . The expansion capacitance substrate is installed in a hollow portion of any one of the plurality of robot arms.
3. The power supply device according to claim 2 .

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