Robot system

Abstract

A robot system (10) comprises: a first controller (201) connected to a DC power supply (290) via a first terminal (27), the first controller (201) having a motor drive circuit (20) to which a DC current of the DC power supply is input and which outputs a drive signal to electric motors (31-1,..., 31-n) of a first robot (31); and a second controller (202) connected to the DC power supply in parallel with the first controller via a second terminal (27), the second controller (202) having a motor drive circuit (20) to which a DC current of the DC power supply is input and which outputs a drive signal to electric motors (32-1,..., 32-n, 51) of a second robot (32) or peripheral equipment (50).

Description

Robot system

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

[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 that has an AC / DC converter and can be connected to the commercial power supply, and a rechargeable power supply device that has a rechargeable battery and a voltage regulator. The connector of the robot controller is connected to either the power supply device for commercial power or the rechargeable power supply device.

[0003] Japanese Patent No. 6892080

[0004] DC microgrids have attracted attention from the perspectives of carbon neutrality and efficient use of energy. The robot system is required to be connected to a DC power supply.

[0005] The technology disclosed herein relates to a robot system. The robot system includes a first controller that is a controller connected to a DC power supply via a first terminal, and has a motor drive circuit into which the DC current of the DC power supply is input and that outputs a drive signal to an electric motor of a first robot, and a second controller that is a controller connected to the DC power supply via a second terminal in parallel with the first controller, and has a motor drive circuit into which the DC current of the DC power supply is input and that outputs a drive signal to an electric motor of a second robot or a peripheral device of the first robot.

[0006] The motor drive circuits of the first and second controllers can receive the DC current from the DC power supply and drive the electric motor of the first robot and the electric motor of the second robot or the peripheral device. The robot system can be connected to the DC power supply.

[0007] Figure 1 shows a robot system. Figure 2 shows a robot system connected to an AC power supply and a robot system connected to a DC power supply. Figure 3 is a flowchart related to the control of the robot system. Figure 4 shows a robot system in which multiple controllers are connected to the DC bus of a DC microgrid. Figure 5 shows a modified robot system. Figure 6 shows a modified robot system. Figure 7 shows the correspondence between the type of power supply connected to the controller and the switching of the switch. Figure 8 shows a modified robot system. Figure 9 shows an example of a robot system.

[0008] The following describes an embodiment of the robot system with reference to the drawings. The robot system described here is illustrative.

[0009] (Basic Configuration of the Robot System) Figure 1 shows the basic structure of the robot system 1. The robot system 1 includes a controller 2. The controller 2 controls the robot 3. The controller 2 is a unit having a single housing 4. Note that the robot 3 is not an essential element of the robot system 1.

[0010] Robot 3 has electric motors as driving elements. Robot 3 has a plurality of electric motors 3-1, ..., 3-n from the first to the nth. Electric motors 3-1, ..., 3-n drive, for example, the joints of robot 3. Robot 3 is, for example, an articulated robot. Note that electric motors 3-1, ..., 3-n are not limited to moving joints. Also, robot 3 is not limited to an articulated robot. Electric motors 3-1, ..., 3-n are AC motors. Electric motors 3-1, ..., 3-n are, for example, three-phase AC motors as shown in Figure 1. Note that the number of phases of electric motors 3-1, ..., 3-n may be single-phase. Electric motors 3-1, ..., 3-n may also be stepping motors. Electric motors 3-1, ..., 3-n are an example of loads for robot system 1.

[0011] The controller 2 has a motor drive circuit 20. The motor drive circuit 20 drives the electric motors 3-1, ..., 3-n of the robot 3. The motor drive circuit 20 has inverters. The motor drive circuit 20 has a plurality of inverters 2-1, ..., 2-n from the first to the nth. Each of the inverters 2-1, ..., 2-n corresponds to each of the electric motors 3-1, ..., 3-n of the robot 3 and is connected in parallel to the DC link 26, which will be described later. Each of the inverters 2-1, ..., 2-n converts the DC current of the DC link 26 into AC current and outputs the AC current as a drive signal to the electric motors 3-1, ..., 3-n. Each of the inverters 2-1, ..., 2-n in Figure 1 is a three-phase inverter and has a bridge circuit including a plurality of switching elements. Note that the inverters 2-1, ..., 2-n of the motor drive circuit 20 are not limited to the configuration example in Figure 1. The symbol Cs represents a smoothing capacitor Cs connected between the positive and negative terminal wires of the DC link 26.

[0012] The controller 2 has a power supply circuit 22. The power supply circuit 22 has the function of converting alternating current to direct current. The power supply circuit 22 is located between the power receiving terminal 27 (described later) and the motor drive circuit 20.

[0013] The power supply circuit 22 includes a rectifier circuit 23. The rectifier circuit 23 is a converter that converts alternating current to direct current. The rectifier circuit 23 is, for example, a full-wave rectifier circuit including a diode. However, the rectifier circuit 23 is not limited to a full-wave rectifier circuit, nor is it limited to a rectifier circuit including a diode. The rectifier circuit 23 may be, for example, a PWM (Pulse Width Modulation) converter. The primary side of the rectifier circuit 23 is connected to the power receiving terminal 27. The secondary side of the rectifier circuit 23 is connected to the DC link 26. In this disclosure, the term "terminal" is used to refer to an inlet or outlet for current provided for the connection of an electrical circuit. For example, it is not intended to be limited to specific physical configurations such as semiconductor leads, terminal blocks, or connectors, and wires connecting circuits or elements, or wiring on a printed circuit board may also correspond to terminals.

[0014] A power supply 28 or a DC power supply 29 is selectively connected to the power receiving terminal 27. The AC power supply 28 may be, for example, a commercial AC power supply. Examples of the AC power supply 28 include a three-phase AC 400V power supply, a three-phase AC 200V power supply, or a three-phase AC 600V power supply. The DC power supply 29 may be, for example, a DC bus of a DC microgrid. The DC power supply 29 may also be a rechargeable battery power supply. The power receiving terminal 27 has three terminals: a first, a second, and a third. A three-phase AC power supply can be connected to the power receiving terminal 27.

[0015] The power supply circuit 22 includes a bypass circuit 24. The bypass circuit 24 connects the primary and secondary sides of the rectifier circuit 23 outside of the rectifier circuit 23. The power supply circuit 22 also includes a switch 25. The switch 25 switches the bypass circuit 24 between conducting and deconducting. As will be described later, the switch 25 is a control switch that switches between on and off in response to a control signal from the control board 21. The switch 25 is an example of a switching element.

[0016] Figure 2 shows the robot system 1 when an AC power supply 28 is connected to the power receiving terminal 27, and when a DC power supply 29 is connected to the power receiving terminal 27. When the AC power supply 28 is connected to the power receiving terminal 27, as shown in the upper part of Figure 2, the switch 25 deactivates the bypass circuit 24. The rectifier circuit 23 converts the input AC current into DC current and outputs it to the DC link 26. When the DC power supply 29 is connected to the power receiving terminal 27, as shown in the lower part of Figure 2, the switch 25 activates the bypass circuit 24. The DC current from the DC power supply 29 bypasses the rectifier circuit 23 and flows to the DC link 26. The rectifier circuit 23 does not convert AC current to DC current.

[0017] Controller 2 has a control board 21. The control board 21 controls the robot 3 through the control of the motor drive circuit 20. The control board 21 is an example of a control circuit. The isolated power supply unit 210 supplies power to the control board 21. The isolated power supply unit 210 is connected to the DC link 26 and supplies power from the DC link 26 to the control board 21. The control board 21 is an example of a load of the robot system 1.

[0018] The control board 21 also controls the power supply circuit 22. The control board 21 detects the type of power supply connected to the power receiving terminal 27 by detecting the current and voltage on the primary side of the rectifier circuit 23. The control board 21 is an example of a detection circuit. When an AC power supply 28 is connected to the power receiving terminal 27, the control board 21 outputs a control signal to turn off the switch 25. As mentioned above, the rectifier circuit 23 converts the input AC current to DC current and outputs it to the DC link 26. When a DC power supply 29 is connected to the power receiving terminal 27, the control board 21 outputs a control signal to turn on the switch 25. As mentioned above, the rectifier circuit 23 does not convert AC current to DC current.

[0019] The controller 2 of the robot system 1 can be connected to a DC power supply 29. The controller 2 can also be connected to an AC power supply 28.

[0020] Figure 3 is a flowchart relating to the control of the robot system 1. In step S31 after the start, the control board 21 detects the current and voltage on the primary side of the rectifier circuit 23. In the following step S32, the control board 21 determines whether a DC power supply 29 is connected to the power receiving terminal 27. If a DC power supply 29 is connected, the control board 21 outputs a control signal to the switch 25 in step S33 to turn the switch 25 on. If an AC power supply 28 is connected, the control board 21 outputs a control signal to the switch 25 in step S34 to turn the switch 25 off.

[0021] Controller 2 can control robot 3 whether it is connected to AC power supply 28 or DC power supply 29. Because controller 2 can be connected to various power sources, its versatility is enhanced.

[0022] (Application of robot system to DC microgrid) Figure 4 shows a robot system 10 applied to a DC microgrid. The robot system 10 comprises a first controller 201 and a second controller 202.

[0023] The first controller 201 is connected to and controls the first robot 31. The second controller 202 is connected to and controls the second robot 32. The first robot 31 and the second robot 32 are separate robots independent of each other. The first robot 31 has a plurality of electric motors 31-1, ..., 31-n. The second robot 32 has a plurality of electric motors 32-1, ..., 32-n. The first robot 31 and the second robot 32 may be robots of the same structure or robots of different structures. The number of robots is not limited to two, but may be three or more. In other words, the number of controllers provided in the robot system 10 is not limited to two, but may be three or more.

[0024] As described above, the first controller 201 is a unit having a housing 4. The second controller 202 is also a unit having a housing 4. The first controller 201 and the second controller 202 are independent of each other. However, in the robot system 10, it is not ruled out that the first controller 201 and the second controller 202 communicate directly or indirectly.

[0025] The first controller 201 and the second controller 202 have the same structure as each other. The first controller 201 and the second controller 202 have substantially the same structure as the controller 2 described above.

[0026] Both the first controller 201 and the second controller 202 have a control board 21, a power supply circuit 22, a power receiving terminal 27, and an isolated power supply unit 210. The power supply circuit 22 has a rectifier circuit 23, a bypass circuit 24, and a switch 25.

[0027] The power receiving terminal 27 of the first controller 201 is connected to the DC bus 290 of the DC microgrid, which serves as a DC power source, and the power receiving terminal 27 of the second controller 202 is also connected to the DC bus 290 of the DC microgrid. The power receiving terminal 27 of the first controller 201 is an example of a first terminal, and the power receiving terminal 27 of the second controller 202 is an example of a second terminal. The first controller 201 and the second controller 202 are in parallel with respect to the DC bus 290. The switch 25 of the first controller 201 is on, and the rectifier circuit 23 is not functioning. The switch 25 of the second controller 201 is also on, and the rectifier circuit 23 is not functioning.

[0028] The first controller 201 and the second controller 202 each have a motor drive circuit 20. The motor drive circuit 20 of the first controller 201 has a plurality of inverters 201-1, ..., 201-n. The motor drive circuit 20 of the second controller 202 has a plurality of inverters 202-1, ..., 202-n. Inverter 201-1 is an example of a first inverter, and inverter 201-n is an example of a third inverter. Inverter 202-1 is an example of a second inverter.

[0029] Here, the motor drive circuit 20 of the first controller 201, including the inverter, drives the electric motors 31-1, ..., 31-n of the first robot 31, and outputs a regenerative DC current to the DC link 26 when the electric motors 31-1, ..., 31-n are decelerated. Similarly, the motor drive circuit 20 of the second controller 202 drives the electric motors 32-1, ..., 32-n of the second robot 32, and outputs a regenerative DC current to the DC link 26 when the electric motors 32-1, ..., 32-n are decelerated.

[0030] The first controller 201 and the second controller 202 have a regenerative discharge resistor 211. The regenerative discharge resistor 211 is connected to the DC link 26. The regenerative discharge resistor 211 has the function of dissipating the regenerative DC current of the electric motors 31-1, ..., 31-n or 32-1, ..., 32-n of the first robot 31 or the second robot 32. The regenerative discharge resistor 211 is an example of a resistor circuit. The regenerative discharge resistor 211 dissipates the regenerative DC current when the first controller 201 or the second controller 202 is connected to the AC power supply 28. The regenerative discharge resistor 211 does not dissipate the regenerative DC current when the first controller 201 or the second controller 202 is connected to the DC power supply 29. In the first controller 201, the regenerative DC current is sent from the DC link 26 to the DC bus 290 through the bypass circuit 24, as shown by the dotted arrow in Figure 4. In the second controller 202, the regenerative DC current is sent from the DC link 26 to the DC bus 290 via the bypass circuit 24, as shown by the dotted arrow in Figure 4.

[0031] (Effects) The first controller 201 and the second controller 202 can be connected to a DC power supply. The robot system 10 is configured by connecting the first controller 201 and the second controller 202 to the DC bus of a DC microgrid. The robot system 10 is a system that can be connected to a DC power supply.

[0032] When the first controller 201 is connected to the DC power supplies 29 and 290, the bypass circuit 24 is activated and the conversion by the rectifier circuit 23 is skipped. With respect to the first controller 201, losses in the power supply circuit 22 are reduced. The first controller 201, which has the bypass circuit 24, is advantageous for improving efficiency when using the DC power supplies 29 and 290. The same applies to the second controller 202.

[0033] The motor drive circuit 20 of the first controller 201 is capable of driving the electric motors 31-1, ..., 31-n of the first robot 31 and outputting regenerative DC current during deceleration of the electric motors 31-1, ..., 31-n. The regenerative DC current from the first controller 201 is sent to the DC bus 290 via the bypass circuit 24. The regenerative DC current from the first controller 201 can be used by the second controller 202.

[0034] Similarly, the motor drive circuit 20 of the second controller 202 is capable of driving the electric motors 32-1, ..., 32-n of the second robot 32 and outputting regenerative DC current during deceleration of the electric motors 32-1, ..., 32-n. The regenerative DC current from the second controller 202 is sent to the DC bus 290 via the bypass circuit 24. The regenerative DC current from the second controller 202 can be used by the first controller 201.

[0035] The robot system 10 has excellent energy-saving performance because it can share regenerative DC current among multiple controllers 201 and 202.

[0036] Furthermore, the controller 2 of the robot system 1 includes a power receiving terminal 27 to which an AC power supply 28 or a DC power supply 29 is selectively connected, a power supply circuit 22 that converts AC current to DC current, and a switch 25 as a switching element.

[0037] As shown in the upper diagram of Figure 2, when the AC power supply 28 is connected to the power receiving terminal 27, the switch 25 is turned off, the bypass circuit 24 is deactivated, and the rectifier circuit 23 converts the AC current to DC current. DC current is supplied to the motor drive circuit 20 through the DC link 26. The motor drive circuit 20 converts the DC current back to AC current to drive the electric motors 3-1, ..., 3-n of the robot 3.

[0038] As shown in the lower diagram of Figure 2, when the DC power supply 29 is connected to the power receiving terminal 27, the switch 25 turns on and the bypass circuit 24 conducts, and the rectifier circuit 23 does not convert AC current to DC current. DC current from the DC power supply 29 is supplied to the motor drive circuit 20 through the DC link 26, and the motor drive circuit 20 can drive the electric motors 3-1, ..., 3-n of the robot 3 in the same manner as described above.

[0039] Controller 2 can control robot 3 whether it is connected to AC power supply 28 or DC power supply 29. Because controller 2 can be connected to various power sources, its versatility is enhanced.

[0040] Furthermore, for example, in the case of a robot system 1 installed in a factory, if the factory's power supply equipment is changed from commercial AC power to a DC microgrid, the controller 2 can control the robot 3 whether it is connected to AC power 28 or DC power 29. The robot system 1 can continue to be used without replacing the controller 2 and robot 3 even if the power supply equipment is changed.

[0041] Furthermore, when the controller 2 is connected to the DC power supply 29, the conversion by the rectifier circuit 23 is skipped, thus reducing losses in the power supply circuit 22. The controller 2 is advantageous for improving efficiency when using the DC power supply 29.

[0042] Furthermore, the control board 21 of the controller 2 determines the type of power supply connected to the power receiving terminal 27 and outputs a control signal to the switch 25 according to the determination result. The controller 2 can automatically switch the power supply circuit 22 according to the type of power supply connected to the controller 2.

[0043] (Modification 1) Note that the switches 25 of controllers 2, 201, and 202 are not limited to control switches, but may also be switches that can be manually switched on or off. When an AC power supply 28 is connected to controller 2, the operator manually switches switch 25 to off, and when a DC power supply 29 or 290 is connected to controller 2, the operator manually switches switch 25 to on.

[0044] (Modification Example 2) The switching element of the controllers 2, 201, and 202 is not limited to the switch 25. FIG. 5 shows a modification example related to the switching element. The controller 2 has a jumper 251 instead of the switch 25 as the switching element. The jumper 251 is located in the middle of the bypass circuit 24. The jumper 251 may be a jumper switch or a jumper wire.

[0045] When the operator of the robot system 1 connects the AC power supply 28 to the controller 2, the operator turns off the jumper 251. On the other hand, when the operator of the robot system 1 connects the DC power supply 29 to the controller 2, the operator turns on the jumper 251. The switching of the power supply circuit 22 may be performed manually.

[0046] Further, the switching element may be configured using a device having a function equivalent to that of the switch 25. The switching element may be configured using, for example, a relay or a semiconductor switching element.

[0047] (Modification Example 3) FIG. 6 shows a circuit diagram of the robot system 1 according to the modification example. The controller 200 according to the modification example is a modification example related to the structure of the power supply circuit 220. The power supply circuit 220 has a function of boosting the voltage of the AC power supply connected to the power receiving terminal 27 and outputting it.

[0048] The power supply circuit 220 includes a rectifier circuit 23, a bypass circuit 24, and a switch 25. The rectifier circuit 23, the bypass circuit 24, and the switch 25 are the same as the power supply circuit 22 described above. The power supply circuit 220 also includes a voltage doubler circuit 221. The voltage doubler circuit 221 has a capacitor and a switch 222. The capacitor is connected to the DC link 26 on the secondary side of the rectifier circuit 23. The switch 222 switches between conduction and disconnection of the primary side of the rectifier circuit 23 and the capacitor. In a state where the switch 222 is turned on and the voltage doubler circuit 221 is conducting, the power supply circuit 220 converts the input AC current into a DC current with double the voltage and outputs it by combining the voltage doubler circuit 221 and the rectifier circuit 23. When the switch 222 is turned off and the voltage doubler circuit 221 is cut off, the voltage doubler circuit 221 does not function and only the rectifier circuit 23 functions, so the power supply circuit 220 converts the input AC current into a DC current without boosting and outputs it. The voltage doubler circuit 221 is an example of a boost circuit.

[0049] A high-voltage AC power supply 28 or a low-voltage AC power supply 28 is connected to the power receiving terminal 27. The high-voltage AC power supply 28 may be, for example, a single-phase AC 200V power supply. The low-voltage AC power supply 28 may be, for example, a single-phase AC 100V power supply.

[0050] The control board 21 detects the type of power supply connected to the power receiving terminal 27 by detecting the current and voltage on the primary side of the rectifier circuit 23. When a high-voltage AC power supply 28 is connected to the power receiving terminal 27, the control board 21 turns off the switch 25 and outputs a control signal to turn off the switch 222. The rectifier circuit 23 converts the input AC current into a DC current, and since the voltage doubler circuit 221 does not function, a high-voltage DC current is output to the DC link 26. On the other hand, when a low-voltage AC power supply 28 is connected to the power receiving terminal 27, the control board 21 turns off the switch 25 and outputs a control signal to turn on the switch 222. The rectifier circuit 23 converts the input AC current into a DC current, and due to the function of the voltage doubler circuit 221, a DC current boosted (e.g., to 200V) is output to the DC link 26.

[0051] The controller 200 can control the robot 3 whether it is connected to a high-voltage AC power supply 28 or a low-voltage AC power supply 28.

[0052] Furthermore, since the controller 200 has a bypass circuit 24 and a switch 25, it can control the robot 3 whether it is connected to an AC power supply 28 or a DC power supply 29. Figure 7 shows the correspondence between the type of power supply connected to the controller 200 and the switching of switches 25 and 222. When a high-voltage AC power supply 28 is connected to the power receiving terminal 27, switch 25 is off and switch 222 is off. When a low-voltage AC power supply 28 is connected to the power receiving terminal 27, switch 25 is off and switch 222 is on. When a DC power supply 29 is connected to the power receiving terminal 27, switch 25 is on and switch 222 is off. The types of power supplies connected to the controller 200 are not limited to two types; there may be three or more types. The robot system 1 has versatility to be connected to various types of power supplies.

[0053] (Modification 4) Figure 8 shows a modified robot system 1. The controller 2000 of the robot system 1 has a notification unit 212. The notification unit 212 notifies the operator by sound (including voice) or display. As illustrated in Figure 8, the control board 21 determines the polarity of the DC power supply 29 connected to the power receiving terminal 27 by detecting the current and voltage on the primary side of the rectifier circuit 23. If the polarity of the DC power supply 29 is connected to the power receiving terminal 27 is reversed, the control board 21 notifies the operator through the notification unit 212 to check the connection of the power supply to the power receiving terminal 27. Upon receiving the notification, the operator can reconnect the DC power supply 29 to the power receiving terminal 27.

[0054] (Other variations) The control board 21 may control the switch 25 of the power supply circuit 22 based on parameters other than the primary current and voltage. Specifically, the control board 21 may switch the switch 25 in response to (a) the load on the secondary side, (b) the remaining battery power connected to the power supply circuit 22, or (c) a command from a higher-level terminal of the controllers 2, 201, 202, for example, via communication.

[0055] In the robot system 10 connected to the DC bus 290, the first controller 201 and the second controller 202 can omit the rectifier circuit 23, the bypass circuit 24, and the switch 25.

[0056] Even when the first controller 201 or the second controller 202 is connected to the AC power supply 28, it may be configured to send the regenerative current to the AC power supply 28. For example, if the rectifier circuit 23 is a PWM converter, the PWM converter may convert the regenerative DC current to AC current and send it to the AC power supply 28. Alternatively, even if the rectifier circuit 23 is a rectifier circuit including a diode, a regenerative power conversion circuit may be added to the first controller 201 or the second controller 202 so that the regenerative power conversion circuit converts the regenerative DC current to AC current and sends it to the AC power supply 28.

[0057] Controllers 2, 201, and 202 are not limited to being connected to robots 3, 31, and 32 to control them, but may also be connected to robots 3, 31, and 32 and their peripheral devices to control or power robots 3, 31, and 32 and their peripheral devices.

[0058] Figure 9 illustrates a specific configuration of the robot system 100, including peripheral equipment. The robot system 100 controls industrial robots 31 and 32 and a conveyor 50. The industrial robots 31 and 32 perform operations on the workpiece 5. The conveyor 50 transports the workpiece 5 to the robots 31 and 32. The conveyor 50 is an example of peripheral equipment for the robots 31 and 32.

[0059] The first controller 201 is connected to and controls the first robot 31. The second controller 202 is connected to and controls the second robot 32. The third controller 203 is connected to the conveyor 50 and controls the electric motor 51 of the conveyor 50. The first controller 201, the second controller 202, and the third controller 203 are connected to a DC bus 290. The first controller 201, the second controller 202, and the third controller 203 may also be connected to an AC power supply. The third controller 203 has the same structure as the first controller 201 and the second controller 202 (see Figure 4).

[0060] Peripheral equipment refers to devices that work in cooperation with robot 3. In addition to the conveyor 50, peripheral equipment may include a moving device for moving robot 3, a turntable for rotating robot 3, or a device that performs processing on the workpiece 5 transported by robot 3, such as an aligner for aligning a circuit board as a workpiece. Peripheral equipment also includes robots. A robot as peripheral equipment is, for example, a robot that transports workpieces to the robot.

[0061] Furthermore, the objects controlled by controllers 2, 201, 202, and 203 are not limited to the industrial robot 3, but may be, for example, social robots.

[0062] The functionality of the elements disclosed herein may be implemented using one or more circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), and / or conventional circuits. The functionality of the elements disclosed herein may be implemented using one or more circuits or processing circuits, including combinations of general-purpose processors, special-purpose processors, integrated circuits, ASICs, FPGAs, and conventional circuits. One or more circuits or processing circuits may be programmed using one or more programs stored together or individually in one or more memories, or otherwise configured to perform the disclosed functionality. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. A processor may be a programmed processor that executes programs stored in memory. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functionality alone or in combination with each other, or hardware programmed to perform the enumerated functionality alone or in combination with each other. The hardware may be any hardware disclosed herein that is programmed or configured to perform the listed functions.

[0063] A computer program, including computer instructions, is stored in memory. The computer instructions provide logic and routines that enable hardware to perform the methods disclosed herein. The hardware includes, for example, processing circuits or circuits. The computer program may be implemented in known formats on computer-readable storage media, computer program products, memory devices, recording media such as CD-ROMs or DVDs, and / or in the memory of FPGAs or ASICs.

[0064] (Embodiment) The embodiments described above are specific examples of the following embodiments.

[0065] (Aspect 1) A robot system (10, 100) comprising: a first controller (201) connected to a DC power supply (290) via a first terminal (27), the first controller (201) having a motor drive circuit (20) to which the DC current of the DC power supply (290) is input and which outputs drive signals to the electric motors (31-1, ..., 31-n) of a first robot (31); and second controllers (202, 203) connected in parallel with the first controller (201) to the DC power supply (290) via a second terminal (27), the second controllers (202, 203) having a motor drive circuit (20) to which the DC current of the DC power supply (290) is input and which outputs drive signals to the electric motors (32-1, ..., 32-n, 51) of a second robot (32) or peripheral equipment (50) of the first robot (31).

[0066] The motor drive circuits (20) of the first and second controllers (201, 202, 203) receive a DC current from a DC power supply (290) and can drive the electric motors (31-1, ..., 31-n, 32-1, ..., 32-n) of the first and second robots (31, 32) or the electric motor (51) of the peripheral equipment (50). The robot system (10) can be connected to the DC power supply (290).

[0067] (Aspect 2) The robot system (10, 100) according to Aspect 1, wherein the motor drive circuit (20) of the first controller (201) has a first inverter (201-1) whose secondary side is connected to the first AC motor (31-1) of the first robot (31) and drives the first AC motor (31-1), and outputs a regenerative DC current to the primary side when the first AC motor (31-1) is decelerated, and the motor drive circuit (20) of the second controller (202) has a second inverter (202-1) whose secondary side is connected to the second AC motor (32-1, 51) of the second robot (32) or the peripheral equipment (50) and drives the second AC motor (32-1, 51), and outputs a regenerative DC current to the primary side when the second AC motor (32-1, 51) is decelerated.

[0068] The motor drive circuit (20) of the first controller (201) can drive the first AC motor (31-1) of the first robot (31) by receiving DC power from a DC power supply (290) via the first inverter (201-1). The motor drive circuit (20) of the second controller (202) can drive the second AC motors (32-1, 51) of the second robot (32) or peripheral equipment (50) by receiving DC power from a DC power supply (290) via the second inverter (202-1).

[0069] (Aspect 3) The robot system (10, 100) according to aspect 2, wherein the motor drive circuit (20) of the first controller (201) has a third inverter (201-n) whose secondary side is connected to the third AC motor (31-n) of the first robot (31) and drives the third AC motor (31-n), and outputs a regenerative DC current to the primary side when the third AC motor (31-n) is decelerated.

[0070] The first controller (201) can control the first robot (31) using multiple inverters (201-1, 201-n) corresponding to multiple AC motors (31-1, 31-n).

[0071] (Aspect 4) The robot system (10, 100) according to aspect 2 or 3, wherein the first controller (201) and the second controller (202) are each connected to the DC bus (290) of a DC microgrid, which serves as the DC power supply.

[0072] A robotic system (10) connected to the DC bus (290) of a DC microgrid can achieve high energy efficiency.

[0073] (Aspect 5) The robot system (10, 100) according to aspect 4, wherein the regenerative DC current of the first controller (201) is sent to the DC bus (290), and the regenerative DC current of the second controller (202) is sent to the DC bus (290).

[0074] The second controller (202) can utilize the regenerative DC current of the first controller (201) via the DC bus (290), and the first controller (201) can utilize the regenerative DC current of the second controller (202) via the DC bus (290), so the robot system (10) has excellent energy-saving performance.

[0075] (Aspect 6) The first terminal (27) is selectively connected to either the DC power supply (29, 290) or the AC power supply (28), the first controller (2, 201, 202) further has a power supply circuit (22) that converts AC current to DC current between the first terminal (27) and the motor drive circuit (20), the power supply circuit (22) performs the conversion when the AC power supply (28) is connected to the first terminal (27), and does not perform the conversion when the DC power supply (29, 290) is connected to the first terminal (27), the robot system (1, 10, 100) according to any one of aspects 1 to 5.

[0076] When an AC power supply (28) is connected to the first terminal (27), the power supply circuit (22) converts the AC current to a DC current. When a DC power supply (29, 290) is connected to the first terminal (27), the power supply circuit (22) does not convert the AC current to a DC current. The first controllers (2, 201, 202) can control the first robot (31) whether they are connected to an AC power supply (28) or a DC power supply (29, 290).

[0077] (Aspect 7) The power supply circuit (22) includes a rectifier circuit (23) that converts the alternating current to the direct current, and a bypass circuit (24) that bypasses the rectifier circuit (23), wherein the bypass circuit (24) is de-conducted when the alternating current power supply (28) is connected to the first terminal (27), and conducts when the direct current power supply (29, 290) is connected to the first terminal (27), the robot system (1, 10, 100) according to aspect 6.

[0078] When the bypass circuit (24) is de-energized, alternating current from the AC power supply (28) is input to the rectifier circuit (23), and the rectifier circuit (23) converts the alternating current to direct current. When the bypass circuit (24) is energized, direct current from the DC power supplies (29, 290) flows through the bypass circuit (24) and bypasses the rectifier circuit (23). The rectifier circuit (23) does not perform the conversion from alternating current to direct current. Since losses in the power supply circuit (22) are reduced, the efficiency of the controllers (2, 201, 202) is improved when using DC power supplies (29, 290).

[0079] (Aspect 8) The robot system (10, 100) according to aspect 6 or 7, wherein the first controller (201, 202) is connected to the secondary side of the power supply circuit (22) and further has a resistor circuit (211) that eliminates the regenerative current of the electric motors (31-1, ..., 31-n) of the first robot (31), and the resistor circuit (211) eliminates the regenerative current of the electric motors (31-1, ..., 31-n) when the AC power supply (28) is connected to the first terminal (27), and does not eliminate the regenerative current when the DC power supply (29, 290) is connected to the first terminal (27).

[0080] If the first controllers (201, 202) are connected to the DC power supply (29, 290), the resistor circuit (211) does not cause the regenerative current to disappear. The robot system (10) has excellent energy-saving performance because the regenerative DC current can be shared among multiple controllers (201, 202).

[0081] If the first controllers (201, 202) are connected to an AC power supply (28) and regenerative current is to be utilized, the regenerative current must be synchronized with the AC power supply (28). This complicates the structure of the first controllers (201, 202). The resistor circuit (211) eliminates the regenerative current, so the structure of the first controllers (201, 202) is simple.

[0082] (Aspect 9) A controller (2, 200, 2000) for a robot system (1), comprising: a power receiving terminal (27); power supply circuits (22, 220) that perform conversion of at least one of current and voltage between a load including at least the drive elements (3-1, ..., 3-n) of the robot (3) and the power receiving terminal (27); and switching elements (25, 222, 251) that switch the power supply circuits (22, 220) to perform the conversion when a first power supply (28) is connected to the power receiving terminal (27), and not perform the conversion when a second power supply (28, 29) of a different type from the first power supply (28) is connected to the power receiving terminal (27).

[0083] When the first power supply (28) is connected to the power receiving terminal (27), the power supply circuits (22, 220) perform conversion of at least one of the current and voltage. When the second power supply (28, 29) is connected to the power receiving terminal (27), the power supply circuits (22, 220) do not perform conversion of at least one of the current and voltage. The controllers (2, 200, 2000) can control the robot (3) whether they are connected to the first power supply (28) or the second power supply (28, 29).

[0084] (Aspect 10) The controller (2, 200, 2000) of the robot system (1) according to aspect 9, wherein the first power supply is an AC power supply (28), the second power supply is a DC power supply (29), and the power supply circuit (22) includes a rectifier circuit (23) that converts the input AC current to a DC current.

[0085] When the controllers (2, 200, 2000) are connected to an AC power supply (28), the rectifier circuit (23) converts the AC current to a DC current, and the DC current is supplied to the load. When connected to a DC power supply (29), the rectifier circuit (23) does not perform the conversion, and the DC current is supplied to the load. The controllers (2, 200, 2000) can control the robot (3) whether they are connected to an AC power supply (28) or a DC power supply (29).

[0086] (Aspect 11) Controller (2, 200, 2000) of the robot system (1) according to aspect 10, wherein the power supply circuit (22) includes a bypass circuit (24) that bypasses the rectifier circuit (23), and the switching element (25, 251) deactivates the bypass circuit (24) when the AC power supply (28) is connected to the power receiving terminal (27), and activates the bypass circuit (24) when the DC power supply (29) is connected to the power receiving terminal (27).

[0087] When the bypass circuit (24) is de-energized, alternating current from the AC power supply (28) is input to the rectifier circuit (23), and the rectifier circuit (23) converts the alternating current to direct current. When the bypass circuit (24) is energized, direct current from the DC power supply (29) flows through the bypass circuit (24) and bypasses the rectifier circuit (23). The rectifier circuit (23) does not perform the conversion from alternating current to direct current. Since the losses in the power supply circuit (22) are reduced, the efficiency of the controller (2, 200, 2000) when using the DC power supply (29) is improved.

[0088] (Aspect 12) A controller (2, 200, 2000) of the robot system (1) according to aspect 11, further comprising a control circuit (21) that detects the type of power supply (28, 29) connected to the power receiving terminal (27), and when the AC power supply (28) is connected to the power receiving terminal (27), it deactivates the bypass circuit (24) through the switching element (25), and when the DC power supply (29) is connected to the power receiving terminal (27), it activates the bypass circuit (24) through the switching element (25).

[0089] The control circuit (21) switches the conduction and deconduction of the bypass circuit (24) via the switching element (25) according to the type of power supply (28, 29) connected to the power receiving terminal (27). The control circuit (21) can automatically switch the power supply circuit (22).

[0090] (Aspect 13) A controller (200) for a robot system (1) according to any one of aspects 9 to 12, wherein the first power supply is a high-voltage AC power supply (28), the second power supply is a lower-voltage AC power supply (28), and the power supply circuit (220) includes a boost circuit (221) for boosting the input AC voltage.

[0091] When a high-voltage AC power supply (28) is connected to the controller (200), the boost circuit (221) does not boost the power supply voltage. When a low-voltage AC power supply (28) is connected, the boost circuit (221) does boost the power supply voltage. The controller (200) can control the robot (3) whether a high-voltage AC power supply (28) or a low-voltage AC power supply (28) is connected.

[0092] (Aspect 14) The power supply circuit (220) includes a rectifier circuit (23) that converts alternating current to direct current, and a voltage multiplier circuit (221) combined with the rectifier circuit (23), which outputs a direct current with a higher voltage than the input alternating current, and the switching element (222) shuts off the voltage multiplier circuit (221) when the high-voltage first power supply (28) is connected to the power receiving terminal (27), and conducts the voltage multiplier circuit (221) when the low-voltage second power supply (28) is connected to the power receiving terminal (27), the controller (200) of the robot system (1) according to aspect 13.

[0093] When the voltage multiplier circuit (221) is interrupted, the alternating current from the high-voltage first power supply, i.e., the high-voltage AC power supply (28), is converted to a direct current by the rectifier circuit (23). When the voltage multiplier circuit (221) is turned on, the alternating current from the low-voltage second power supply (28), i.e., the low-voltage AC power supply (28), is converted to a direct current and boosted by the rectifier circuit (23) and the voltage multiplier circuit (221).

[0094] (Aspect 15) A controller (200) of the robot system (1) according to aspect 14, further comprising a control circuit (21) that detects the type of power supply (28) connected to the power receiving terminal (27), and when the high-voltage first power supply (28) is connected to the power receiving terminal (27), shuts off the voltage multiplier circuit (221) through the switching element (222), and when the low-voltage second power supply (28) is connected to the power receiving terminal (27), conducts the voltage multiplier circuit (221) through the switching element (222).

[0095] The control circuit (21) switches between conducting and disconnecting the voltage multiplier circuit (221) via a switching element (222) depending on the type of power supply (28) connected to the power receiving terminal (27). The control circuit (21) can automatically switch the power supply circuit (220).

[0096] (Aspect 16) A controller (2000) for a robot system (1) according to any one of aspects 9 to 15, further comprising a notification unit (212) that detects the polarity of the voltage applied to the power receiving terminal (27) and, if the polarity of the voltage is incorrect, provides notification prompting confirmation of the power supply connection to the power receiving terminal (27).

[0097] The polarity of the DC power supply (29) connected to the controller (2000) is determined, and if the DC power supply (29) is connected to the controller (2000) in the wrong direction, the notification unit (212) issues a notification. The operator of the robot system (1) can then reconnect the DC power supply (29) to the controller (2000) in the correct direction.

[0098] (Aspect 17) A controller (2, 200, 2000) for a robot system (1) according to any one of aspects 9 to 16, further comprising a motor drive circuit (20) connected to the secondary side of the power supply circuit (22, 220), to which a DC current from the power supply circuit (22, 220) is input and which outputs drive signals for electric motors (3-1, ..., 3-n) as drive elements of the robot (3).

[0099] The power supply circuits (22, 220) of the controllers (2, 200, 2000) are switched according to the first power supply (28) and the second power supply (28, 29), so that the motor drive circuit (20) can be common to the first power supply (28) and the second power supply (28, 29).

[0100] (Aspect 18) A method for controlling power supply circuits (22, 220) in a controller (2, 200, 2000) of a robot system (1), wherein a detection circuit (21) detects the type of power supply (28, 29) connected to the power receiving terminal (27) of the controller (2, 200, 2000) of the robot system (1), and if the detected power supply is a first power supply (28), the power supply circuits (22, 220) receive a control signal from the control circuit (21) and perform a conversion of at least one of current and voltage between the power receiving terminal (27) and a load including at least the drive elements (3-1, ..., 3-n) of the robot (3), and if the detected power supply is a second power supply (28, 29), the power supply circuits (22, 220) receive a control signal from the control circuit (21) and do not perform the conversion.

[0101] The power supply circuits (22, 220) are switched depending on the type of power supply (28, 29) connected to the power receiving terminal (27). The controllers (2, 200, 2000) can control the robot (3) whether they are connected to the first power supply (28) or the second power supply (28, 29).

[0102] (Aspect 19) A method for controlling a power supply circuit (22) in a controller (2, 200, 2000) of a robot system (1) according to aspect 18. The first power supply is an AC power supply (28), the second power supply is a DC power supply (29), the power supply circuit (22) includes a rectifier circuit (23) that converts AC current to DC current, and a bypass circuit (24) that bypasses the rectifier circuit (23), and when the detected power supply is an AC power supply (28), the bypass circuit (24) is deactivated and the rectifier circuit (23) converts AC current to DC current upon receiving a control signal from the control circuit (21), and when the detected power supply is a DC power supply (29), the bypass circuit (24) is activated and the rectifier circuit (23) does not perform the conversion.

[0103] The controllers (2, 200, 2000) can control the robot (3) whether they are connected to an AC power supply (28) or a DC power supply (29).

[0104] (Aspect 20) The first power supply is a high-voltage AC power supply (28), and the second power supply is a lower-voltage AC power supply (28) than the first power supply, and the power supply circuit (220) includes a rectifier circuit (23) that converts AC current to DC current, and a voltage multiplier circuit (221) combined with the rectifier circuit (23) that outputs a DC current of a higher voltage than the input AC voltage, and when the detected power supply is the high-voltage first power supply (28), the voltage multiplier circuit (221) is shut off by receiving a control signal from the control circuit (21), and the rectifier circuit (23) converts AC current to DC current, and when the detected power supply is the low-voltage second power supply (28), the voltage multiplier circuit is shut off, the voltage multiplier circuit (221) conducts, and the rectifier circuit (23) and the voltage multiplier circuit (221) output a high-voltage DC current. A method for controlling the power supply circuit (220) in the controller (200) of the robot system (1) described in embodiment 18.

[0105] The controller (200) can control the robot (3) whether it is connected to a high-voltage AC power supply (28) or a low-voltage AC power supply (28).

[0106] 1 Robot System 10 Robot System 2 Controllers 2-1, ..., 2-n Inverters 20 Motor Drive Circuits 201 First Controller 201-1, ..., 201-n Inverters 202 Second Controller 202-1, ..., 202-n Inverters 211 Regenerative Discharge Resistor (Resistor Circuit) 22 Power Supply Circuit 23 Rectifier Circuit 24 Bypass Circuit 27 Power Receiving Terminals (First Terminal, Second Terminal) 28 AC Power Supply 29 DC Power Supply 290 DC Bus (DC Power Supply) 3 Robots 3-1, ..., 3-n Electric Motors 31 First Robot 32 Second Robot 31-1, ..., 31-n Electric Motors 32-1, ..., 32-n Electric Motors

Claims

1. A robot system comprising: a first controller connected to a DC power supply via a first terminal, which has a motor drive circuit that receives the DC current of the DC power supply and outputs a drive signal to the electric motor of a first robot; and a second controller connected in parallel with the first controller to the DC power supply via a second terminal, which has a motor drive circuit that receives the DC current of the DC power supply and outputs a drive signal to the electric motor of a second robot or peripheral equipment of the first robot.

2. A robot system according to claim 1, wherein the motor drive circuit of the first controller has a first inverter whose secondary side is connected to the first AC motor of the first robot and drives the first AC motor, and outputs a regenerative DC current to the primary side when the first AC motor is decelerated, and the motor drive circuit of the second controller has a second inverter whose secondary side is connected to the second AC motor of the second robot or the peripheral equipment and drives the second AC motor, and outputs a regenerative DC current to the primary side when the second AC motor is decelerated.

3. A robot system according to claim 2, wherein the motor drive circuit of the first controller has a third inverter whose secondary side is connected to the third AC motor of the first robot and drives the third AC motor, and which outputs a regenerative DC current to the primary side when the third AC motor is decelerated.

4. A robot system according to claim 2 or 3, wherein the first controller and the second controller are each connected to a DC bus of a DC microgrid, which serves as the DC power supply.

5. A robot system according to claim 4, wherein the regenerative DC current of the first controller is sent to the DC bus, and the regenerative DC current of the second controller is sent to the DC bus.

6. A robot system according to any one of claims 1 to 5, wherein the first terminal is selectively connected to either a DC power supply or an AC power supply, the first controller further includes a power supply circuit between the first terminal and the motor drive circuit that converts AC current to DC current, the power supply circuit performs the conversion when the AC power supply is connected to the first terminal, and does not perform the conversion when the DC power supply is connected to the first terminal.

7. A robot system according to claim 6, wherein the power supply circuit comprises a rectifier circuit for converting the alternating current to the direct current, and a bypass circuit for bypassing the rectifier circuit, wherein the bypass circuit deactivates when the alternating current is connected to the first terminal, and activates when the direct current is connected to the first terminal.

8. A robot system according to claim 6 or 7, wherein the first controller is connected to the secondary side of the power supply circuit and further comprises a resistor circuit that eliminates the regenerative current of the electric motor of the first robot, the resistor circuit eliminates the regenerative current of the electric motor when the AC power supply is connected to the first terminal, and does not eliminate the regenerative current when the DC power supply is connected to the first terminal.

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