robot systems

Abstract

It has a function to suppress inrush current and is compatible with both DC and AC power sources. [Solution] The controller 10 of the robot system 1 includes a rectifier circuit 21 located between the input terminal 11 and the output terminal 12, a reactor L1 and a switching element 3 arranged in series with the power line 13 connecting the rectifier circuit 21 and the output terminal 12, a capacitor C1 arranged between the positive line 13a and the negative line 13b of the power line 13, and a control circuit 4 that outputs a control signal to intermittently turn the switching element 3 on and off when power is supplied to the input terminal 11.

Description

Technical Field

[0001] The technology disclosed herein relates to a controller for a robot system.

Background Art

[0002] Patent Document 1 describes a conventional robot system. The conventional robot system includes a robot arm and a robot controller. The robot arm is a mobile robot arm that is movable rather than a stationary type. The robot controller can be selectively connected to a commercial power supply which is an AC power supply and a battery which is a DC power supply. More specifically, the conventional robot system includes a power supply device for commercial power having an AC / DC converter and being connectable to the commercial power supply, and a rechargeable power supply device having a rechargeable battery and a voltage regulator. A power supply device for commercial power or a rechargeable power supply device is connected to a connector of the robot controller.

[0003] Patent Document 2 shows a mobile robot having a function of controlling so as to suppress an inrush current flowing through a capacitor when switching the power supply of a load from a commercial AC power supply to a battery. In Patent Document 2, a triac is provided in the front stage of a rectifier circuit, and the triac is turned on and off when switching between the commercial power supply and the battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The application of robotic systems is expanding into various fields. As the scope of application of robotic systems broadens, there is a growing need for versatility in robotic systems that can utilize various types of power sources.

[0006] The configuration in Patent Document 2 assumes that an AC power supply is connected to the power receiving coupler corresponding to the input terminal, and therefore cannot accommodate cases where a DC power supply is connected to the input terminal. [Means for solving the problem]

[0007] The technology disclosed herein relates to a controller for a robot system. The controller for a robot system is An input terminal connected to the power supply, Output terminals connected to a load including the robot's drive elements, A rectifier circuit located between the input terminal and the output terminal, A reactor and a switching element are arranged in series in the power line connecting the rectifier circuit and the output terminal, A capacitor is placed between the positive and negative terminal lines of the power supply line, The system includes a control circuit that outputs a control signal to intermittently turn the switching element on and off when power is supplied to the input terminal. [Effects of the Invention]

[0008] The controller of the aforementioned robot system has a function to suppress inrush current and can handle both DC and AC power supplies. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a circuit diagram of the robot system. [Figure 2] Figure 2 shows a robot system connected to an AC power supply and a robot system connected to a DC power supply. [Figure 3] Figure 3 shows a robot system including an articulated robot. [Figure 4] Figure 4 shows an example of a robot system. [Figure 5] Figure 5 is a flowchart related to the control of the robot system. [Figure 6] Figure 6 shows an example of current and voltage waveforms during soft-start operation. [Figure 7] Figure 7 is a circuit diagram of a modified robot system. [Modes for carrying out the invention]

[0010] The following describes embodiments of the robot system controller with reference to the drawings. The robot system and robot system controller described herein are illustrative examples. In the circuit diagrams shown below, the components relevant to this disclosure are simplified in their illustration. Therefore, components that are shown as directly connected may, in the actual circuit configuration, be indirectly connected by other components placed between them. In this disclosure, the term "connection" is used as a broad concept encompassing electrical connection. In other words, in this disclosure, the term "connection" includes not only direct connections between elements but also indirect and electrical connections via passive elements, etc.

[0011] Figure 1 shows the circuit diagram of robot system 1. Robot system 1 includes a controller 10. Controller 10 controls robot R1. Note that robot R1 is not an essential element of robot system 1. Controller 10 is not limited to being connected to robot R1 and controlling robot R1, but may also be connected to robot R1 and its peripheral equipment and control or supply power to robot R1 and its peripheral equipment.

[0012] FIG. 4 illustrates a specific configuration of the robot system 1 including peripheral devices. The controlled objects of the robot system 1 are industrial robots R1-1, R1-2 and a conveyor G. The robots R1-1, R1-2 perform operations on the workpiece Wk. The conveyor G conveys the workpiece Wk to the robots R1-1, R1-2. The conveyor G is an example of the peripheral devices of the robots R1-1, R1-2.

[0013] The controller 10-1 is connected to the robot R1-1 and controls the robot R1-1. The controller 10-2 is connected to the robot R1-2 and controls the robot R,1-2. The controller 10-3 is connected to the conveyor G and controls the electric motor G1 of the conveyor G. The controllers 10-1, 10-2 and 10-3 have, for example, the same structure as the controller 10 illustrated in FIG. 1.

[0014] Note that the peripheral device is a device that performs operations in cooperation with the robot R1. In addition to the conveyor G, the peripheral devices include a moving device that moves the robot R1, a turntable that turns the robot R1, or a device that executes processing on the workpiece Wk conveyed by the robot R1, for example, an aligner that aligns a substrate as the workpiece. The peripheral devices include a robot. The robot as the peripheral device is, for example, a robot that conveys a workpiece to the robot.

[0015] In addition, the controlled objects of the controllers 10-1, 10-2 are not limited to the industrial robots R1-1, R1-2, and may be, for example, social robots.

[0016] Robot R1 has a load R2 including a driving element. The driving element of robot R1 includes an electric motor R21. Robot R1 may be an articulated robot. In the example of FIG. 3, robot R1 has a plurality of electric motors R21-1, …, R21-n. For example, when the articulated robot has 6 axes, robot R1 has six electric motors R21-1, …, R21-6. Note that the number of axes is not limited to 6 axes. The electric motors R21-1, …, R21-n drive, for example, the joints of robot R1. The electric motors R21-1, …, R21-n are AC motors. The electric motor is, for example, a three-phase AC motor. Note that the number of phases of the electric motors R21-1, …, R21-n may be single-phase. The electric motors R21-1, …, R21-n may be stepping motors. The electric motor R21 is an example of the load R2. Note that robot R1 is not limited to an articulated robot. Also, the electric motor R21 is not limited to moving a joint.

[0017] Controller 10 includes an input terminal 11 and an output terminal 12. The input terminal 11 is connected to a power supply P. An AC power supply P1 and a DC power supply P2 are selectively connected to the input terminal 11 as the power supply P. The AC power supply P1 may be, for example, a commercial AC power supply. The AC power supply P1 can be exemplified by, for example, a three-phase AC 400V power supply, a three-phase AC 200V power supply, or a three-phase AC 600V power supply. The AC power supply P1 may be a single-phase AC power supply. The DC power supply P2 is exemplified by a rechargeable battery power supply. The DC power supply P2 may be a DC bus of a DC microgrid. The input terminal 11 has three power receiving terminals. A three-phase AC power supply can be connected to the input terminal 11. The output terminal 12 is connected to a load R2 including a driving element of the robot. In the present disclosure, the term “terminal” is used in the concept of an entrance and exit of current provided for connection of an electric circuit. For example, it is not intended to be limited to a specific physical configuration such as a semiconductor lead, a terminal block, or a connector, and wires for connecting circuits or elements or wirings on a printed circuit board may correspond to the terminal.

[0018] The controller 10 comprises a power supply circuit 2, a switching element 3, a reactor L1, a diode D1, a capacitor C1, and a control circuit 4. The power supply circuit 2 comprises a converter 20, a bypass element 22, and a switching circuit 23. The converter 20 is located between the input terminal 11 and the output terminal 12. When an AC power supply P1 is connected to the input terminal 11, the converter 20 converts the AC current supplied from the AC power supply P1 into a DC current and outputs it to the power line 13.

[0019] The converter 20 is, for example, a rectifier circuit 21. The rectifier circuit 21 is located between the input terminal 11 and the output terminal 12. When an AC power supply P1 is connected to the input terminal 11, the rectifier circuit 21 converts the AC current supplied from the AC power supply P1 into a DC current and outputs it to the power line 13. The rectifier circuit 21 is, for example, a full-wave rectifier circuit composed of multiple diodes. The power line 13 connects the output of the rectifier circuit 21 to the output terminal 12. Note that the converter 20 is not limited to a rectifier circuit 21. For example, a PWM converter may be used as the converter 20 instead of the rectifier circuit 21.

[0020] As shown in Figure 2, when a DC power supply P2 is connected to the input terminal 11 and a DC power supply is supplied, the bypass element 22 bypasses the connection between the input and output of the rectifier circuit 21, allowing conduction. On the other hand, when an AC power supply P1 is connected to the input terminal 11 and an AC power supply is supplied, the bypass element 22 disconnects the connection between the input and output of the rectifier circuit 21. Specifically, the bypass element 22 includes, for example, a connecting wire that connects the input and output of the rectifier circuit 21 and a switch 25 located on the connecting wire. The switch 25 switches between conducting and disconnecting the bypass element 22. The configuration of the switch 25 is not particularly limited, and for example, a semiconductor switch, a relay, or other mechanical switch can be used. The switch 25 is a control switch that switches between conducting (on) and disconnecting (off) in response to a control signal from the switching circuit 23. The switching circuit 23 detects the type of power supply connected to the input terminal 11 by detecting the current or voltage on the primary side of the rectifier circuit 21. As shown in the upper part of Figure 2, the switching circuit 23 outputs a control signal to turn off the switch 25 when an AC power supply P1 is connected to the input terminal 11. As previously mentioned, the rectifier circuit 21 converts the input AC current into DC current and outputs it to the power line 13. As shown in the lower part of Figure 2, the switching circuit 23 outputs a control signal to turn on the switch 25 when a DC power supply P2 is connected to the input terminal 11. When the switch 25 is turned on, the rectifier circuit 21 does not perform rectification.

[0021] The switching element 3 and the reactor L1 are placed on the power line 13 connecting the output of the rectifier circuit 21 to the output terminal 12. More specifically, the switching element 3 and the reactor L1 are placed in series with the positive terminal line 13a of the power line 13. The switching element 3 only needs to be able to switch between conducting and disconnecting based on a control signal, and the specific device is not particularly limited. The switching element 3 is, for example, a transistor such as a MOSFET or IGBT using a semiconductor with a standard bandgap. A diode may be connected in parallel to the transistor. In the above example, the diode may be a separate element from the transistor, or it may be built into the transistor.

[0022] The switching element 3 is, for example, a transistor using a wide-bandgap semiconductor. A diode may be connected in parallel to the transistor. The diode is, for example, a diode using a wide-bandgap semiconductor.

[0023] Wide-bandgap semiconductors refer to materials with a bandgap wider than, for example, silicon (Si). Examples of wide-bandgap semiconductors include SiC (silicon carbide), GaN (gallium nitride), and GaAs (gallium arsenide). The same applies to other wide-bandgap semiconductors described later. In switching element 3, the diode may be a separate element from the transistor, or it may be built into the transistor. Furthermore, wide-bandgap semiconductors may be used for both the transistor and the diode, or a wide-bandgap semiconductor may be used for either the transistor or the diode.

[0024] Capacitor C1 is located between the positive terminal line 13a and the negative terminal line 13b of the power line 13. The voltage across capacitor C1 is measured by a voltage sensor 16. The control board 28 acquires the voltage across capacitor C1 measured by the voltage sensor 16. The control board 28 controls the drive elements of the robot R1. The aforementioned switching circuit 23 may be an independent circuit or may be mounted on the control board 28. The power supply unit 29 supplies power to the control board 28. The power supply unit 29 is connected to the power line 13 and supplies power from the power line 13 to the control board 28. The power supply unit 29 and the control board 21 are examples of loads in the robot system 1. The voltage sensor 16, the control board 28, and the power supply unit 29 are not essential components of the controller 10 according to this disclosure.

[0025] In the example shown in Figure 3, the controller 10 has one or more drive inverters 5. The drive inverter 5 is located between the power line 13 and the drive elements of the robot R1. The drive inverter 5 converts the DC power output from the rectifier circuit 21 to the power line 13, or bypasses the rectifier circuit 21, into AC power and outputs it from the output terminal 12 of the controller 10. The output terminal 12 of the controller 10 is connected to the drive elements of the robot R1 (e.g., electric motor R2). The drive inverter 5 has a bridge circuit including multiple switching elements. As shown in Figure 3, the drive inverter 5 may have multiple inverters 5-1, ..., 5-n. Inverters 5-1, ..., 5-n correspond to the electric motors R21-1, ..., R21-n of the robot R1, respectively. Inverters 5-1, ..., 5-n are connected in parallel to the power line 13. Each inverter 5-1, ..., 5-n converts the DC current from the power line 13 into AC current, and outputs the AC current as a drive signal to the electric motors R21-1, ..., R21-n.

[0026] Inverters 5-1, ..., 5-n are, for example, three-phase inverters in which three legs 30 are bridged. In other words, inverters 5-1, ..., 5-n each have three legs 30. Each leg 30 includes two switching elements 31 connected in series. For example, each switching element 31 includes a transistor 32 and a diode 33 connected in parallel with each other. For example, wide-bandgap semiconductors are used as the transistor 32 and diode 33.

[0027] Note that the diode 33 may be a separate element from the transistor 32, or it may be built into the transistor 32. Wide-bandgap semiconductors may be used for both the transistor 32 and the diode 33, or a wide-bandgap semiconductor may be used for either one. For example, a wide-bandgap semiconductor may be used for the transistor 32, and silicon may be used for the diode 33. For example, a wide-bandgap semiconductor may be used for the diode 33, and silicon may be used for the transistor 32.

[0028] The control circuit 4 outputs a control signal that intermittently turns the switching element 3 on and off when power is supplied to the input terminal 11. The control circuit 4 is mounted, for example, on the control board 28. The control circuit 4 outputs the above control signal so that the switching element 3 is repeatedly turned on and off for a predetermined period of time after power is supplied to the input terminal. This realizes a soft-start mode that suppresses inrush current. Figure 6 shows an example of the current waveform of the current sensor 17 and the DC bus voltage of the power line 13 in soft-start mode. As shown in Figure 6, the control circuit 4, using the above control signal, repeatedly turns off the switching element 3 when the current value of the current sensor 17, in other words, the current value flowing through the reactor L1, exceeds a predetermined third threshold Th3, and turns on the switching element 3 when it falls below a predetermined fourth threshold Th4. As a result, the waveform of the current sensor 17, i.e., the reactor current, fluctuates between the third threshold Th3 and the fourth threshold Th4. The DC bus voltage of the power line 13 gradually increases toward the target voltage. Note that the third threshold Th3 is greater than the fourth threshold Th4. For example, the third threshold Th3 is 20[A] and the fourth threshold Th4 is 15[A].

[0029] The duration of the soft start mode may be measured by a timer or other means in the control circuit 4, or it may be set based on the voltage rise speed measured by the voltage sensor 16.

[0030] Note that the current sensor 17 is not a required component. The voltage sensor 16 is not a required component. For example, the on and off duty cycle of the switching element 3 may be set as follows: For example, it may be fixed to a constant duty cycle. For example, the on duty cycle may be increased over time. For example, the on duty cycle may be gradually increased over time from the time the power is turned on, until the on duty cycle is increased to 100%. In other words, the switching element 3 may be turned on after a predetermined time has elapsed. For example, the on duty cycle may be increased stepwise or discretely. For example, the initial value of the on duty cycle may be set to 0%, and the on duty cycle may be gradually increased starting from 0%.

[0031] When the soft-start mode ends, the control circuit 4 transitions to normal mode. In normal mode, the control circuit 4 makes the switching element conductive. In normal mode, if the current value measured by the current sensor 17 exceeds a predetermined first threshold, the control circuit 4 may turn off the switching element 3. Furthermore, when the switching element 3 is in the off state, if the current value measured by the current sensor 17 falls below the above second threshold, the control circuit 4 may return the switching element 3 to a conductive state. The second threshold is lower than the first threshold. For example, the first threshold is 200[A] and the second threshold is 180[A]. This enables operation in a protection mode that protects against instantaneous voltage drops and automatically recovers from the off state, as well as in an automatic recovery mode.

[0032] The functions of the control circuit 4 described above can be implemented, for example, by a microcomputer. A microcomputer is a computer configured or programmed to perform the disclosed functions. The functions of the elements disclosed herein, for example, the functions of the control circuit 4, can be performed using a circuit or processing circuit, including a general-purpose processor, a dedicated processor, an integrated circuit, an ASIC (Application Specific Integrated Circuit), a conventional circuit, and / or a combination thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor. The operation of the control circuit 4 may be implemented using a circuit such as the one shown in Figure 1. Specifically, the control circuit 4 includes a comparator 41. The negative terminal of the comparator 41 is connected to the positive line 13a, and the positive terminal is connected to the constant voltage source 42. The output of the comparator 41 is supplied as a control signal to the gate of the switching element 3.

[0033] Diode D1 has its anode connected to the negative line 13b of the power supply line 13 and its cathode connected to the positive line 13a of the power supply line 13. Diode D1 functions as a freewheeling diode for the step-down chopper.

[0034] Figure 5 is a flowchart of the control of the robot system 1. In step S31 after the start, the switching circuit 23 detects the current or voltage of the power supply supplied to the input terminal 11. In the following step S32, the switching circuit 23 determines whether the power supplied to the input terminal 11 is DC or AC. If it is determined that DC power is supplied to the input terminal 11, the flow proceeds to step S33, and the switching circuit 23 outputs a control signal to switch 25 to turn it ON. If it is determined that AC power is supplied to the input terminal 11, the flow proceeds to step S34, and the switching circuit 23 outputs a control signal to switch 25 to turn it OFF. In step S35, the controller 10 operates in soft-start mode. Specifically, the control circuit 4 intermittently turns the switching element 3 on and off for a predetermined period after power is supplied to the input terminal 11. A specific example of operation for the soft-start mode is as described above. In step S36, the controller 10 operates in normal mode. Specifically, the control circuit 4 makes the switching element 3 conductive after a predetermined period of time has elapsed since power was supplied to the input terminal 11. The controller 10 may also operate in the protection operation mode and automatic recovery mode described above in normal mode.

[0035] (Effects and Benefits) As described above, by configuring the controller 10 of the robot system 1 according to this embodiment, a function to suppress inrush current is realized, and it is possible to support both DC and AC power inputs.

[0036] Furthermore, by using a wide-bandgap semiconductor as the switching element 3, operation at high frequencies becomes possible. This allows for a reduction in the size of the reactor L1, and thus enables a smaller and lighter controller 10. In addition, using a wide-bandgap semiconductor reduces the on-resistance compared to using a semiconductor with a standard bandgap, thereby suppressing heat generation.

[0037] (Variation 1) Figure 7 is a circuit diagram of the robot system 1 according to this modified example. As shown in Figure 7, a switching element 18 may be used instead of the diode D1. For example, a transistor such as a MOSFET or IGBT can be used as the switching element 18. When the diode D1 is replaced with the switching element 18, the switching element 18 operates complementary to the switching element 3. Specifically, when the switching element 3 is turned on, the switching element 18 is turned off, and when the switching element 3 is turned off, the switching element 18 is turned on. This provides the same effect as when using the diode D1. Furthermore, by using a transistor as the switching element 18, conduction losses are reduced, so heat generation can be suppressed. The switching element 18 is an example of a second switching element.

[0038] (Modification 2) In the bypass element 22, the switching between conduction and interruption is not limited to the switch 25. For example, a jumper may be used instead of the switch 25. The jumper constitutes the intermediate portion of the connecting wire that connects the input and output of the rectifier circuit 21. The jumper may be a jumper switch or a jumper wire.

[0039] When the operator of robot system 1 connects AC power supply P1 to controller 10, they switch the jumper to the off state, disconnecting the connection between the input and output of rectifier circuit 21. On the other hand, when the operator of robot system 1 connects DC power supply P2 to controller 10, they switch the jumper to the on state, connecting the input and output of rectifier circuit 21 to a conductive state. The installation and removal of the jumper of power supply circuit 2 may be performed automatically or manually by the operator. Furthermore, a device having a function equivalent to a switch 25 may be used as the switching method for the bypass element 22.

[0040] (Aspect) The embodiments described above are specific examples of the following embodiments.

[0041] (Aspect 1) The input terminal (11) is connected to the power supply (P), An output terminal (12) connected to a load (R2) including the drive elements of the robot (R1), A converter (20) is located between the input terminal (11) and the output terminal (12), A reactor (L1) and a switching element (3) are arranged in series in the power line (13) connecting the converter (20) and the output terminal (12), A capacitor (C1) is placed between the positive electrode line (13a) and the negative electrode line (13b) of the power supply line (13), The system includes a control circuit (4) that outputs a control signal to intermittently turn the switching element (3) on and off when power is supplied to the input terminal (11), Controller (10) of the robot system (1).

[0042] According to the above embodiment, since the switching element is located on the DC power line (13) connecting the converter (20) and the output terminal (12), it is possible to handle both DC and AC power inputs. Furthermore, since the switching element (3) is intermittently switched on and off, a soft-start function is realized. A function to suppress inrush current is realized. A resistor element for inrush prevention suppression can be omitted, enabling miniaturization.

[0043] (Aspect 2) A wide-bandgap semiconductor is used as the switching element (3). A controller (10) of the robot system (1) described in Embodiment 1.

[0044] By using a wide-bandgap semiconductor as the switching element (3), the controller (10) can be miniaturized.

[0045] (Aspect 3) The converter (20) is provided with a bypass element (22) that connects the input and output of the converter (20) when a DC power supply (P2) is supplied to the input terminal (11), while disconnecting the connection between the input and output of the converter (20) when an AC power supply (P1) is supplied to the input terminal (11). A controller (10) of the robot system (1) according to embodiment 1 or embodiment 2.

[0046] According to this embodiment, the controller (10) can be connected to both a DC power supply (P2) and an AC power supply (P1). As described above, the technology of this disclosure has the feature that a soft-start function can be realized regardless of whether a DC power supply (P2) or an AC power supply (P1) is connected.

[0047] (Aspect 4) The power supply line (13) is equipped with a current sensor (17) for measuring the current, The control circuit (4) intermittently turns the switching element (3) on and off based on the current value measured by the current sensor (17). A controller (10) of the robot system (1) described in any one of embodiments 1 to 3.

[0048] Since the switching element (3) is controlled on and off based on the measured current value, control that reflects the actual operating state can be achieved.

[0049] (Appendix 5) The power supply line (13) is equipped with a current sensor (17) for measuring the current, The control circuit (4) is, For a predetermined period after power is applied to the input terminal (11), the switching element (3) operates in a soft-start mode, intermittently switching on and off. After the predetermined period has elapsed, the switching element (3) operates in a normal mode in which it is in a conductive state. A controller (10) for the robot system (1) described in any one of embodiments 1 to 4.

[0050] By controlling the system in this manner, inrush current during power-on can be effectively prevented. Furthermore, during normal operation, the switching element (3) does not affect the operation.

[0051] (Aspect 6) The control circuit (4) is, In the normal mode described above, if the current value of the current sensor (17) exceeds a predetermined first threshold, the switching element (3) is shut off. In the aforementioned disconnected state, if the current value of the current sensor (17) falls below a second threshold lower than the first threshold, the switching element (3) is returned to a conductive state. Controller (10) of the robot system (1) described in Embodiment 5.

[0052] In this embodiment, a protection operation mode is implemented in normal operation mode to protect against instantaneous voltage drops. After the current value of the current sensor (17) exceeds a predetermined first threshold and the system enters a tripped state, an automatic recovery mode is implemented that automatically recovers from the tripped state.

[0053] (Aspect 7) The capacitor (C1) is equipped with a voltage sensor (16) for measuring the voltage of the capacitor. The control circuit (4) intermittently turns the switching element (3) on and off based on the voltage value measured by the voltage sensor (16). A controller (10) for the robot system (1) described in any one of embodiments 1 to 6.

[0054] Since the switching element (3) is controlled on and off based on the measured voltage value, control that reflects the actual operating state can be achieved.

[0055] (Pattern 8) The control circuit (4) has a comparator (41) that compares the voltage of the power line (13) with a predetermined voltage, and outputs the output of the comparator (41) as the control signal to the switching element. A controller (10) for the robot system (1) described in any one of embodiments 1 to 7.

[0056] Since the switching element (3) is controlled on and off based on the voltage state of the power line (13), control that reflects the actual operating state can be achieved.

[0057] (Aspect 9) The diode (D1) is provided with its anode connected to the negative terminal line (13b) of the power supply line (13) and its cathode connected to the positive terminal line (13a) of the power supply line (13). A controller (10) for the robot system (1) described in any one of embodiments 1 to 8.

[0058] Diode (D1) functions as a freewheeling diode for the step-down chopper.

[0059] (Aspect 10) The power supply line (13) includes a second switching element (18) positioned between the positive electrode line (13a) and the negative electrode line (13b). A controller (10) for the robot system (1) described in any one of embodiments 1 to 8.

[0060] The second switching element (18) functions as a freewheeling element for the step-down chopper. For example, by using a transistor as the switching element (18), conduction losses are reduced, and thus heat generation can be suppressed.

[0061] (Aspect 11) The load is an electric motor that drives the robot (R1). A controller (10) for a robot system (1) according to any one of embodiments 1 to 10.

[0062] (Aspect 12) The input terminal (11) is connected to the power supply (P), An output terminal (12) connected to a load (R2) including the drive elements of the robot (R1), A converter (20) is located between the input terminal (11) and the power line (13), A drive inverter (5) is located between the power line (13) and the output terminal (12) and converts DC power to AC power, A reactor (L1) and a switching element (3) using a wide-bandgap semiconductor are arranged in series on the power line (13), The system includes a control circuit (4) that outputs a control signal to intermittently turn the switching element (3) on and off when power is supplied to the input terminal (11), Controller (10) of the robot system (1).

[0063] According to the above embodiment, since the switching element is located on the DC power line (13) connecting the converter (20) and the drive inverter (5), it is possible to handle both DC and AC power inputs. Furthermore, since the switching element (3) is intermittently switched on and off, a soft-start function is realized. A function to suppress inrush current is realized. A resistor element for inrush prevention suppression can be omitted, enabling miniaturization.

[0064] (Aspect 13) The converter is a rectifier circuit composed of a diode bridge. A controller for a robot system according to any one of embodiments 1 to 12.

[0065] (Aspect 14) The aforementioned converter is a PWM converter. A controller for a robot system according to any one of embodiments 1 to 12.

[0066] (Aspect 15) The control circuit increases the on-duty cycle of the switching element as time elapses from the time since power was supplied to the input terminal, and turns the switching element on after a predetermined time has elapsed. A controller for a robot system according to any one of embodiments 1 to 14.

[0067] By increasing the on-duty cycle over time, inrush current can be suppressed while shortening the startup time of the robot and robot system. [Explanation of Symbols]

[0068] 1. Robot System 10 Controllers 11 input terminals 12 output terminals 13 Power lines 13a Positive electrode line 13b Negative electrode line 17 Current Sensor 18 Switching element (second switching element) 20 Converters 21 Rectifier circuit 22 Bypass elements 3 Switching elements 4. Control circuits 41 Comparator C1 Capacitor D1 diode L1 Reactor P power supply P1 AC power supply P2 DC power supply R1 Robot R2 load

Claims

1. A robot having multiple drive elements, The robot is equipped with a controller for controlling the robot, The aforementioned controller, An input terminal connected to the power supply, Multiple output terminals connected to the aforementioned multiple drive elements, A converter located between the input terminal and the power line, A plurality of drive inverters are positioned between the power line and the plurality of output terminals, each converting the DC power of the power line into AC power and outputting it to the corresponding output terminal. A reactor and a switching element using a wide-bandgap semiconductor connected in series on the power line, A capacitor located between the positive and negative terminal lines of the power supply line, A control circuit that outputs a control signal to intermittently turn the switching element on and off when power is supplied to the input terminal, The converter includes a connecting wire that connects the input and output of the converter, and a switch located on the connecting wire, and a bypass element that connects and conducts the input and output of the converter when a DC power supply is supplied to the input terminal, while disconnecting the connection between the input and output of the converter when an AC power supply is supplied to the input terminal, The system includes a current sensor for measuring the current in the power line, The control circuit operates in a soft-start mode for a predetermined time after power is applied to the input terminal, in which the switching element is turned off when the current value measured by the current sensor exceeds a predetermined first threshold, and turned on when it falls below a predetermined second threshold that is less than the first threshold, and then operates in a normal mode after the predetermined time has elapsed, in which the switching element is made conductive. Robot system.

2. In the robot system according to claim 1, In the normal mode, the control circuit turns off the switching element when the current value measured by the current sensor exceeds a predetermined third threshold, and when the current value measured by the current sensor falls below a predetermined fourth threshold that is smaller than the third threshold, the control circuit returns the switching element to a conductive state. Robot system.

3. In the robot system according to claim 2, The fourth threshold is greater than the first threshold. Robot system.

4. In the robot system according to any one of claims 1 to 3, The robot is a multi-joint robot having multiple joints, Each of the aforementioned multiple drive elements drives the corresponding joint. Robot system.

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