Control devices and robot systems

Abstract

This invention provides a control device and robot system that effectively and flexibly utilizes regenerated electricity with a simple configuration. The control device is characterized by comprising: a drive circuit section that receives regenerated electricity from a motor from multiple input / output terminals; a discharge resistor section connected in parallel with the drive circuit section, receiving regenerated electricity from the drive circuit section and consuming electricity when the voltage value of the regenerated electricity exceeds a threshold; a second converter circuit section connected in parallel with a first converter circuit section, converting alternating current input from the terminals into direct current and outputting it; a first step-down circuit section that steps down the voltage of the current output from the second converter circuit section and outputs it; a power-on control circuit section that operates using the direct current output from the first step-down circuit section and controls the drive circuit section; and a regenerated electricity supply section having a regenerated diode connected to the discharge resistor section, outputting the direct current of the regenerated electricity to the first step-down circuit section.

Description

Technical Field

[0001] This invention relates to control devices and robot systems. Background Technology

[0002] In recent years, due to soaring labor costs and a shortage of skilled workers, factories have increasingly adopted robots with robotic arms for manufacturing, processing, and assembly operations, accelerating the automation of tasks previously performed manually. Furthermore, robots are required to operate in energy-efficient ways.

[0003] For example, the robot control device of the robot described in Patent Document 1 has a smoothing capacitor for storing regenerative power generated by a motor driving a robotic arm. The regenerative power is stored in the smoothing capacitor for driving, for example, a DC fan.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2006-280076

[0005] However, in the robot control device described in Patent Document 1, since the regenerated electricity is supplied intermittently to the power-consuming DC fan, it is necessary to discharge the power according to the timing of power consumption, making the control and structure complex. Thus, it is difficult to effectively and flexibly utilize regenerated electricity with a simple structure. Summary of the Invention

[0006] The control device of the present invention is characterized in that it controls the drive of a motor of a robotic arm and comprises: a terminal for supplying power from an AC power source; a plurality of input / output terminals for inputting and outputting power to the motor; a first converter circuit section for converting AC current input from the terminal into DC current and outputting it; a drive circuit section for converting DC current output from the first converter circuit section into AC current and outputting it to the plurality of input / output terminals, and receiving regenerative power from the motor from the plurality of input / output terminals; and a discharge resistor section connected in parallel with the drive circuit section and receiving the regenerative power from the drive circuit section, wherein the regenerative power is discharged from the motor. When the voltage value of the force exceeds a threshold, the discharge resistor consumes power; the second converter circuit, connected in parallel with the first converter circuit, converts the AC current input from the terminal into DC current and outputs it; the first buck circuit reduces the voltage of the current output from the second converter circuit and outputs it; the power-on control circuit operates using the DC current output from the first buck circuit and controls the drive circuit; and the regenerative power supply unit has a regenerative diode connected to the discharge resistor and outputs the DC current of the regenerative power to the first buck circuit.

[0007] The robot system of the present invention is characterized by comprising: a robot having a robotic arm; and a control device of the present invention for controlling the drive of the robotic arm. Attached Figure Description

[0008] Figure 1 This is a diagram showing the overall configuration of a robot system equipped with the control device of the present invention.

[0009] Figure 2 yes Figure 1 The diagram shows a block diagram of the robot system.

[0010] Figure 3A yes Figure 1 The circuit diagram of the control device is shown.

[0011] Figure 3B yes Figure 3A The circuit diagram of the comparator is shown.

[0012] Figure 4 It indicates that it comes from Figure 1 The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section.

[0013] Figure 5 It indicates that it comes from Figure 1 The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section.

[0014] Figure 6 It indicates that it comes from Figure 1 The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section.

[0015] Figure 7 yes Figure 1 A variation of the circuit diagram of the control device shown.

[0016] Explanation of reference numerals in the attached figures

[0017] 1…Robot, 3…Control device, 4…Teaching device, 10…Robotic arm, 10A…Power control circuit, 11…Base, 12…First arm, 13…Second arm, 14…Third arm, 15…Fourth arm, 16…Fifth arm, 17…Sixth arm, 20…End effector, 31…Control unit, 32…Storage unit, 33…Communication unit, 40…Display, 41…Control unit, 42…Storage unit, 43…Communication unit, 60A…Noise reduction capacitor, 60B…Surge protection resistor, 61…AC power supply, 62…First converter circuit, 62A…Input terminal, 62B…Input / output terminal, 63…Regenerative capacitor, 64…Drive circuit, 65…Discharge resistor, 66…Potential detection unit, 67…Switch, 68…Comparator, 681…Comparator body, 69…Terminal, 70…Terminal, 71…Second converter circuit, 72…Power factor improvement circuit 73…First step-down circuit section, 74…Power-on control circuit section, 75…Second step-down circuit section, 76…Regenerative power supply section, 100…Robot system, 171…Joint, 172…Joint, 173…Joint, 174…Joint, 175…Joint, 176…Joint, 721…Output voltage setting resistor, 761…Regenerative diode, A3…Central value, B3…Central value, D1…Motor driver, D2…Motor driver, D3…Motor driver, D4…Motor driver, D5…Motor driver, D6…Motor driver, E1…Encoder, E2…Encoder, E3…Encoder, E4…Encoder, E5…Encoder, E6…Encoder, M1…Motor, M2…Motor, M3…Motor, M4…Motor, M5…Motor, M6…Motor, TCP…Tool center point, R1…Resistor, R2…Resistor, R3…Resistor, R4…Resistor. Detailed Implementation

[0018] Hereinafter, the control device of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0019] Implementation

[0020] Figure 1 This is a diagram showing the overall configuration of a robot system equipped with the control device of the present invention. Figure 2 yes Figure 1 The diagram shows a block diagram of the robot system. Figure 3A yes Figure 1 The circuit diagram of the control device is shown. Figure 3B yes Figure 3A The circuit diagram of the comparator is shown. Figure 4 It indicates that it comes from Figure 1 The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section. Figure 5 It indicates that it comes from Figure 1The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section. Figure 6 It indicates that it comes from Figure 1 The figure shows an example of the relationship between the threshold voltage of the regenerated power of the motor and the voltage value of the power input to the first step-down circuit section. Figure 7 yes Figure 1 A variation of the circuit diagram of the control device shown.

[0021] It should be noted that, for ease of explanation, the following will also refer to robotic arm 10. Figure 1 The side of the base 11 is called the "base end", and its opposite side, namely the end effector 20, is called the "front end".

[0022] like Figure 1 As shown, the robot system 100 of the present invention includes a robot 1, a control device 3 for controlling the robot 1, and a teaching device 4.

[0023] First, let's explain robot 1.

[0024] In this embodiment, Figure 1 The robot 1 shown is a single-arm, 6-axis vertical articulated robot with a base 11 and a robotic arm 10. Additionally, an end effector 20 can be mounted on the front end of the robotic arm 10. It should be noted that the end effector 20 can be a component of the robot 1, or it can be a component independent of the robot 1, i.e., not a component of the robot 1.

[0025] It should be noted that robot 1 is not limited to the configuration shown in the figure; for example, it could also be a dual-armed multi-joint robot. Additionally, robot 1 could also be a horizontal multi-joint robot.

[0026] The base 11 is a support body that supports the robotic arm 10 in a driveable manner at its base end, for example, fixed to the floor in a factory. The base 11 of the robot 1 is electrically connected to the control device 3 via a relay cable. It should be noted that the connection between the robot 1 and the control device 3 is not limited to, for example,... Figure 1 The connection can be made via wired connection as shown, but it can also be made wirelessly. Alternatively, robot 1 and control device 3 can be connected via a network such as the Internet.

[0027] In this embodiment, the robotic arm 10 has a first arm 12, a second arm 13, a third arm 14, a fourth arm 15, a fifth arm 16, and a sixth arm 17, which are connected in the above order from the base 11 side. It should be noted that the number of arms in the robotic arm 10 is not limited to six; for example, it can have one, two, three, four, five, or more than seven arms. Furthermore, the overall length and size of each arm are not particularly limited and can be appropriately set.

[0028] The base 11 and the first arm 12 are connected via a joint 171. Thus, the first arm 12 can rotate relative to the base 11 about a first rotation axis extending parallel to the vertical direction. The first rotation axis coincides with the normal to the floor surface of the floor that fixes the base 11.

[0029] The first arm 12 and the second arm 13 are connected via a joint 172. Thus, the second arm 13 can rotate relative to the first arm 12 about a second axis of rotation extending horizontally. This second axis of rotation is parallel to an axis orthogonal to the first axis of rotation.

[0030] The second arm 13 and the third arm 14 are connected via a joint 173. Thus, the third arm 14 can rotate relative to the second arm 13 about a third axis of rotation extending horizontally. This third axis of rotation is parallel to the second axis of rotation.

[0031] The third arm 14 and the fourth arm 15 are connected via joint 174. Thus, the fourth arm 15 can rotate relative to the third arm 14 about a fourth rotation axis parallel to the central axis of the third arm 14. The fourth rotation axis is orthogonal to the third rotation axis.

[0032] The fourth arm 15 and the fifth arm 16 are connected via joint 175. Thus, the fifth arm 16 can rotate relative to the fourth arm 15 about the fifth rotation axis. The fifth rotation axis is orthogonal to the fourth rotation axis.

[0033] The fifth arm 16 and the sixth arm 17 are connected by a joint 176. Thus, the sixth arm 17 can rotate relative to the fifth arm 16 about a sixth rotation axis. The sixth rotation axis is orthogonal to the fifth rotation axis.

[0034] Additionally, the sixth arm 17 is the foremost arm in the robotic arm 10. This sixth arm 17 can be displaced together with the end effector 20 under the drive of the robotic arm 10.

[0035] Figure 1 The end effector 20 shown has a gripping part capable of holding a workpiece or tool. When the end effector 20 is mounted on the sixth arm 17, the front end of the end effector 20 becomes the tool center point TCP.

[0036] Robot 1 includes motors M1, M2, M3, M4, M5, and M6 as drive units, and encoders E1, E2, E3, E4, E5, and E6. Motor M1 is integrated into joint 171, causing the first arm 12 to rotate relative to the base 11 about a first rotation axis. Motor M2 is integrated into joint 172, causing the first arm 12 and the second arm 13 to rotate relative to each other about a second rotation axis. Motor M3 is integrated into joint 173, causing the second arm 13 and the third arm 14 to rotate relative to each other about a third rotation axis. Motor M4 is integrated into joint 174, causing the third arm 14 and the fourth arm 15 to rotate relative to each other about a fourth rotation axis. Motor M5 is integrated into joint 175, causing the fourth arm 15 and the fifth arm 16 to rotate relative to each other about a fifth rotation axis. Motor M6 is integrated into joint 176, causing the fifth arm 16 and the sixth arm 17 to rotate relative to each other about a sixth rotation axis. Each motor M1 to M6 is a three-phase motor driven by three-phase AC.

[0037] Additionally, encoder E1 is integrated into joint 171 to detect the position of motor M1. Encoder E2 is integrated into joint 172 to detect the position of motor M2. Encoder E3 is integrated into joint 173 to detect the position of motor M3. Encoder E4 is integrated into joint 174 to detect the position of motor M4. Encoder E5 is integrated into the fifth arm 16 to detect the position of motor M5. Encoder E6 is integrated into the sixth arm 17 to detect the position of motor M6. It should be noted that "detecting position" here refers to detecting the rotation angle of the motor, including the amount of rotation in both directions and the angular velocity; this detected information is called "position information."

[0038] like Figure 2 As shown, motor drivers D1 to D6 are connected to the corresponding motors M1 to M6 respectively, controlling the drive of the motor. Motor drivers D1 to D6 are respectively built into joints 171, 172, 173, 174, the fifth arm 16, and the sixth arm 17.

[0039] Encoders E1 to E6, motors M1 to M6, and motor drivers D1 to D6 are electrically connected to control device 3. The position information (rotation amount, etc.) of motors M1 to M6 detected by encoders E1 to E6 is sent to control device 3 as electrical signals. Then, based on this position information, the power control circuit 74 in the power control circuit 10A of control device 3... Figure 2 The motor drivers D1 to D6 shown output control signals to control the energization of motors M1 to M6, driving motors M1 to M6 as desired. That is, controlling the robotic arm 10 means controlling the drive of motors M1 to M6 to control the movements of the first arm 12 to the sixth arm 17 belonging to the robotic arm 10.

[0040] An end effector 20 can be detachably mounted at the front end of the robotic arm 10. In this embodiment, the end effector 20 is composed of a gripper having a pair of claws that can approach or separate from each other, thereby gripping and releasing a workpiece or tool. It should be noted that the end effector 20 is not limited to the configuration shown in the figure; for example, it may also have a suction part that grips the workpiece or tool by suction. In addition, the end effector 20 may also be, for example, a grinding machine, a cutting machine, a spray gun, a laser irradiator, a screwdriver, a wrench, or other tools.

[0041] Next, the control device 3 and the teaching device 4 will be explained.

[0042] like Figure 1 As shown, in this embodiment, the control device 3 is located separately from the robot 1. However, this configuration is not limited; the control device 3 may also be integrated into the base 11. Furthermore, the control device 3 has the function of controlling the drive of the robot 1 and is electrically connected to the aforementioned motors M1 to M6, the AC power supply 61, and other parts of the robot. The control device 3 includes a control unit 31, a storage unit 32, and a communication unit 33. These parts are connected to each other, for example, via a bus, in a manner that allows for communication.

[0043] The control unit 31, for example, is composed of a CPU (Central Processing Unit), which reads and executes various programs, such as motion programs, stored in the storage unit 32. Signals generated by the control unit 31 are sent to various parts of the robot 1 via the communication unit 33, and signals from various parts of the robot 1 are received by the control unit 31 via the communication unit 33. Thus, the robotic arm 10 can perform specified tasks under specified conditions.

[0044] Storage unit 32 stores various programs executed by control unit 31. Examples of storage units 32 include those configured with volatile memory such as RAM (Random Access Memory), non-volatile memory such as ROM (Read Only Memory), and removable external storage devices.

[0045] The communication unit 33 uses an external interface such as a wired LAN (Local Area Network) or a wireless LAN to transmit and receive signals with the control device 3. In this case, communication can be conducted via a server (not shown), or via a network such as the Internet.

[0046] like Figure 1 and Figure 2As shown, the teaching pendant 4 is a command device for teaching operations and includes a display 40 as a display unit. This display 40 also serves as the operation unit for teaching the robotic arm 10's motion programs. That is, it has the function of creating and inputting motion programs. The display 40 is composed of a touch panel, allowing operators to input various operations and information related to teaching by using their fingers or a stylus. The display 40 is composed of, for example, liquid crystal or organic EL, and can display various images in color or black and white. Furthermore, the touch panel in the display 40 can be either pressure-sensitive or capacitive.

[0047] The teaching device 4 has a control unit 41, a storage unit 42, and a communication unit 43.

[0048] The control unit 41 is composed of at least one processor, such as a CPU (Central Processing Unit), and reads and executes various programs, such as teaching programs, stored in the storage unit 42. Furthermore, the control unit 41 has the function of controlling the operation of the display 40. Specifically, the control unit 41 displays a rectangular operation screen on the display 40 and generates a motion program for the robot 1 based on information input from the operation screen through touch or other means at a desired location. The motion program generated by the control unit 41 is stored in the storage unit 42 and transmitted to the control device 3 via the communication unit 43. Thus, the control device 3 can specify a program to cause the robotic arm 10 to perform a predetermined task under predetermined conditions.

[0049] Storage unit 42 stores various programs that can be executed by control unit 41. Examples of storage units 42 include those configured with volatile memory such as RAM (Random Access Memory), non-volatile memory such as ROM (Read Only Memory), and removable external storage devices. Furthermore, the storage unit 42 stores the operation programs created by control unit 41.

[0050] The communication unit 43 communicates with the control device 3 via an external interface such as a wired LAN (Local Area Network) or a wireless LAN. In this case, communication can be conducted via a server (not shown) or a network such as the Internet. The communication unit 43 sends information related to the operation program stored in the storage unit 42 to the control device 3. Furthermore, the communication unit 43 can also receive information stored in the storage unit 32 and store it in the storage unit 42.

[0051] Next, refer to Figure 3AThe control device 3 of the robot system 100 will be described in detail. The control device 3 includes a control unit 31, which has a power control circuit 10A. The power control circuit 10A includes an input terminal (terminal) 62A, a noise reduction capacitor 60A, a surge protection resistor 60B, a first converter circuit 62, a regenerative capacitor 63 electrically connected to the output side of the first converter circuit 62, a drive circuit 64, an input / output terminal 62B, a discharge resistor 65, a potential detection unit 66, a switch 67, a comparator 68, a second converter circuit 71, a power factor improvement circuit 72, a first buck converter circuit 73, a power-on control circuit 74, a second buck converter circuit 75, and a regenerative power supply unit 76. It should be noted that the term "connection" includes not only direct connection between terminals but also connections between terminals via wires or the like.

[0052] The AC power supply 61 is, for example, a 200V AC power supply. The power output from the AC power supply 61, i.e., electrical energy, is input to the first converter circuit section 62 via input terminal 62A, noise reduction capacitor 60A, and surge protection resistor 60B. Input terminal 62A is the terminal where power is supplied from the AC power supply 61, and AC current is input. Figure 3A As shown, the two input terminals 62A are respectively connected to the first converter circuit section 62 (described later) via wires. The wire connecting the lower input terminal 62A to the first converter circuit section 62 is a low-potential wire, and the wire connecting the upper input terminal 62A to the first converter circuit section 62 is a high-potential wire, with the high-potential wire having a higher potential than the low-potential wire. Additionally, the two input terminals 62A are respectively connected to the second converter circuit section 71 (described later) via wires. The wire connecting the lower input terminal 62A to the second converter circuit section 71 is a low-potential wire, and the wire connecting the upper input terminal 62A to the second converter circuit section 71 is a high-potential wire with a higher potential than the low-potential wire. In this embodiment, the low-potential wires are connected to ground.

[0053] In the noise reduction capacitor 60A, two capacitors are connected in series, and a ground wire is connected between these capacitors. By passing through the noise reduction capacitor 60A, noise in the power output from the AC power supply 61 is removed, and a stable power supply can be provided.

[0054] A surge protector 60B is installed on the high-potential wire and includes a resistor and a switch that bypasses the resistor to prevent inrush current from flowing through. When the control device 3 is started, an excessive current, known as inrush current, is generated in order to store electricity in the regenerative capacitor 63, etc. Therefore, when the control device 3 is started, the switch is open, current flows through the resistor, consuming power, thereby preventing inrush current from flowing into the first converter circuit section 62, etc. This improves safety. On the other hand, after the control device 3 is started, power is stored in the capacitor, etc., and no inrush current is generated. Therefore, when the switch is closed, current does not flow through the resistor, suppressing power consumption by the resistor.

[0055] The first converter circuit section 62 is a bridge rectifier circuit using diodes, which converts the AC current input from the AC power supply 61 through the noise reduction capacitor 60A and the surge protection resistor section 60B into DC current and outputs it.

[0056] A regenerative capacitor 63 is connected to the output side of the first converter circuit section 62. The regenerative capacitor 63 stores the regenerated power generated by motors M1 to M6. In addition, the regenerative capacitor 63 also functions as a smoothing capacitor to smooth the voltage output from the first converter circuit section 62.

[0057] Additionally, the drive circuit section 64 includes motor drivers D1 to D6. Each of the motor drivers D1 to D6 has an inverter circuit containing six switching elements. The motor drivers D1 to D6 are each subjected to PWM control, converting the DC current output from the first converter circuit section 62 into AC current. In this embodiment, this is converted into three-phase AC and selectively supplied to each of the corresponding motors M1 to M6 via the input / output terminal 62B. Furthermore, motors M1 to M6 generate regenerative power, which is input to the motor drivers D1 to D6 via the input / output terminal 62B. It should be noted that the magnitude and timing of the power output from the drive circuit section 64 to each of the motors M1 to M6 are set by the power-on control circuit section 74. Figure 3A As shown, the two terminals of the drive circuit section 64 are respectively connected to the first converter circuit section 62 via wires. The wire connecting the lower terminal of the drive circuit section 64 to the first converter circuit section 62 is a low-potential wire, and the wire connecting the upper terminal of the drive circuit section 64 to the first converter circuit section 62 is a high-potential wire with a higher potential than the low-potential wire. In this embodiment, the ground wire is connected to the low-potential wire.

[0058] Furthermore, the terminals for outputting power from the drive circuit section 64 to motors M1 to M6 are input / output terminals 62B. Power is input and output between motor drivers D1 to D6 and motors M1 to M6 via the input / output terminals 62B. Since each motor M1 to M6 is a three-phase motor, three input / output terminals 62B are provided for each motor.

[0059] The robotic arm 10 is driven and displaced by drive motors M1 to M6. However, when the power supply to motors M1 to M6 is stopped and the displacement of the robotic arm 10 is to be rapidly decelerated or stopped, the robotic arm 10 will not stop instantly due to its inertial force during the displacement. Back electromotive force, i.e., regenerated power, is generated by motors M1 to M6.

[0060] Motors M1 through M6 each generate regenerative power independently. The term "regenerative power" as used below refers to the total regenerative power generated by motors M1 through M6.

[0061] The discharge resistor section 65 is connected in parallel with the drive circuit section 64. When the power supply to the motors M1 to M6 is stopped to decelerate, i.e., when regeneration of the motors M1 to M6 is performed, the regenerated electricity generated by the motors M1 to M6 as regeneration energy is converted into heat and consumed. Regeneration refers to making the drive source work by generating back electromotive force when the drive source such as the motors M1 to M6 decelerates rapidly, that is, making the drive source work as a generator.

[0062] When driving motors M1 to M6, the power supply control circuit 74 operates using power from the AC power supply 61 to control the drive circuit 64, supplying AC, particularly three-phase AC, power to motors M1 to M6 at a predetermined timing, frequency, and voltage. Conversely, when stopping the driving of motors M1 to M6, the power supply control circuit 74 controls the drive circuit 64 to stop supplying power to motors M1 to M6. At this time, as described above, a back electromotive force is generated in motors M1 to M6, and its power is stored in the regenerative capacitor 63. Then, if the capacity of the regenerative capacitor 63 is exceeded, the remaining power is converted into heat by the discharge resistor 65, which dissipates heat.

[0063] In addition, switch 67 is connected in series with discharge resistor 65. When switch 67 is in the ON state, it supplies power to discharge resistor 65; when switch 67 is in the OFF state, it does not supply power to discharge resistor 65.

[0064] The potential detection unit 66 detects the potential of the regenerator 63. The signal corresponding to the detected value by the potential detection unit 66 is input to terminal 69 of the comparator 68.

[0065] Comparator 68 generates a signal to turn on switch 67 when the voltage value of the regenerated power from motors M1 to M6 exceeds a threshold. That is, comparator 68 compares the voltage value of the regenerated power detected by potential detection unit 66 with a set threshold and outputs a signal corresponding to the comparison result to switch 67. When the voltage value of the regenerated power is greater than the threshold, comparator 68 outputs a signal to turn on switch 67. Conversely, when the voltage value of the regenerated power is less than the threshold, comparator 68 outputs a signal to turn off switch 67. It should be noted that this threshold will also be referred to as "threshold B" below. Furthermore, as... Figure 3B As shown, comparator 68 includes: a comparator body 681, which compares and outputs a signal corresponding to the comparison result; a terminal 69, which is connected to a potential detection unit 66; a terminal 70, which is connected to a second step-down circuit unit 75 described later; a resistor R1, which is disposed on the wire connecting the comparator body 681 and the terminal 70; a resistor R2, which is disposed on the wire connecting the comparator body 681 and the resistor R1 and the output side of the comparator body 681, and is hysteretic by bypassing the comparator body 681; a resistor R3, which is disposed at a position closer to the terminal 70 than the resistor R1; and a resistor R4, which is disposed on the wire connecting the resistor R1 and the resistor R3 and the ground wire.

[0066] The parts of the power control circuit 10A, excluding comparator 68, described above are the "high voltage side" circuits where a higher voltage is applied. Next, the "low voltage side" circuits of the power control circuit 10A, where a lower voltage is applied, will be described.

[0067] The second converter circuit section 71 is connected in parallel with the first converter circuit section 62. It converts the AC current input from the AC power supply 61 through the input terminal 62A, the noise reduction capacitor 60A, and the surge protection resistor section 60B into DC current and outputs it to the power factor improvement circuit section 72. The second converter circuit section 71 is a bridge rectifier circuit using diodes.

[0068] The power factor improvement circuit 72 is a circuit used to bring the power factor of the AC power supply 61 close to 1. Furthermore, the power factor improvement circuit 72 has the function of suppressing the high-frequency current generated by the AC power supply 61 to below a predetermined value to protect the CPU and other components described later. The power factor improvement circuit 72 has an output voltage setting resistor 721 for adjusting the output voltage. By appropriately setting the resistance value of the output voltage setting resistor 721, the voltage output from the power factor improvement circuit 72 to the first buck circuit 73, i.e., the voltage of the current input to the first buck circuit 73, can be set. Hereinafter, the voltage of the current input to the first buck circuit 73 will also be referred to as "voltage value A".

[0069] Thus, the control device 3 includes a power factor improvement circuit 72, which improves the power factor of the power supplied from the regenerated power supply 76 and outputs it to the first step-down circuit 73. As a result, the power factor can be improved to effectively and flexibly utilize the power from the AC power source 61, and the voltage of the current output to the first step-down circuit 73 can be easily set.

[0070] The first step-down circuit section 73 is a linear or switching DC / DC converter that steps down the input voltage and outputs it to the power-on control circuit section 74 and the second step-down circuit section 75. It should be noted that the voltage supplied to the power-on control circuit section 74 and the second step-down circuit section 75 is, for example, stepped down to approximately 24V.

[0071] The power-on control circuit section 74 and the second step-down circuit section 75 are connected in parallel. The power-on control circuit section 74 is a circuit that constitutes part of the aforementioned control section 31. It operates using the DC current output from the first step-down circuit section 73 to control the drive circuit section 64. That is, the power-on control circuit section 74 generates a drive signal and outputs it to the drive circuit section 64.

[0072] The second step-down circuit 75 has the same structure and function as the first step-down circuit 73, except for the different degree of voltage transformation. It further steps down the voltage reduced by the first step-down circuit 73 and supplies it as the power supply voltage for the comparator to terminal 70 of the comparator 68. Thus, the comparator 68 can operate. It should be noted that the comparator power supply voltage supplied to terminal 70 of the comparator 68 is stepped down to, for example, approximately 5V by the second step-down circuit 75. The comparator 68 compares the input value from terminal 69 with the input value from terminal 70 to control the opening and closing of the switch 67. Figure 3A As shown, the two terminals of the power-on control circuit section 74 and the second step-down circuit section 75 are respectively connected to the second converter circuit section 71 via wires. The wire connecting the lower terminals of the power-on control circuit section 74 and the second step-down circuit section 75 to the second converter circuit section 71 is a low-potential wire, and the wire connecting the upper terminals of the power-on control circuit section 74 and the second step-down circuit section 75 to the second converter circuit section 71 is a high-potential wire with a higher potential than the low-potential wire. In this embodiment, the ground wire is connected to the low-potential wire.

[0073] The regenerative power supply unit 76 includes a regenerative diode 761, which outputs the DC current of the regenerative power generated on the high-voltage side to the first step-down circuit unit 73. It should be noted that the regenerative power supplied by the regenerative power supply unit 76 to the first step-down circuit unit 73 includes direct regenerative power generated by motors M1 to M6 and regenerative power discharged by the regenerative capacitor 63. The input terminal of the regenerative diode 761 in the regenerative power supply unit 76, i.e., the anode, is connected to the high-potential wire between the output terminal of the first converter circuit unit 62 and the discharge resistor unit 65. The output terminal of the regenerative diode 761, i.e., the cathode, is connected to the input terminal of the high-potential wire of the first step-down circuit unit 73. The regenerative diode 761 allows only one direction for the regenerative power, i.e., as... Figure 3A As indicated by arrow A, current flows from the motors M1 to M6 towards the first step-down circuit section 73, while current in the opposite direction is blocked. In other words, the regenerative power supply section 76 supplies regenerative power from the high-voltage side to the low-voltage side. The regenerative power supplied by the regenerative power supply section 76 is input to the first step-down circuit section 73. Furthermore, the regenerative power supply section 76 has a wire connecting the low-potential wire of the first converter circuit section 62 and the low-potential wire of the second converter circuit section 71. This allows the two low-potential wires to be at the same potential, and as described later, this further increases the frequency of supplying regenerative power to the power-on control circuit section 74, enabling more efficient and flexible utilization of regenerative power.

[0074] Previously, due to the lack of a supply unit equivalent to the regenerated power supply unit 76, and the absence of a configuration that supplied regenerated power from the high-voltage side to the low-voltage side, it was impossible to effectively and flexibly utilize regenerated power. However, in this invention, regenerated power is supplied from the high-voltage side to the low-voltage side, and after being stepped down, it is flexibly utilized as power to drive the power-on control circuit unit 74. In addition, regenerated power is also supplied to the second step-down circuit unit 75 to power the comparator 68. As a result, regenerated power exceeding the capacity of the regenerated capacitor 63 can be effectively and flexibly utilized. In particular, the power-on control circuit unit 74 is a circuit that continuously consumes power during the operation of the robot 1. Therefore, by adopting a configuration that flexibly utilizes regenerated power as power for driving the power-on control circuit unit 74, the circuitry for discharge control that matches the timing of power consumption can be omitted, and regenerated power can be effectively and flexibly utilized with a simple configuration.

[0075] Thus, the control device 3 controls the drive of motors M1 to M6 of the robotic arm 10, and includes: an input terminal 62A for supplying power from an AC power source 61; multiple input / output terminals 62B for inputting and outputting power to and from motors M1 to M6; a first converter circuit 62 for converting the AC current input from the input terminal 62A into DC current and outputting it; a drive circuit 64 for converting the DC current output from the first converter circuit 62 into AC current and outputting it to the multiple input / output terminals 62B, and receiving regenerative power from motors M1 to M6 from the multiple input / output terminals 62B; and a discharge resistor 65 connected in parallel with the drive circuit 64 and receiving regenerative power from the drive circuit 64. The system generates electricity. When the voltage of the regenerated electricity exceeds a threshold B, the discharge resistor 65 consumes power. The second converter circuit 71, connected in parallel with the first converter circuit 62, converts the AC current input from the input terminal 62A into DC current and outputs it. The first step-down circuit 73 steps down the voltage of the current output from the second converter circuit 71 and outputs it. The power-on control circuit 74 operates using the DC current output from the first step-down circuit 73 to control the drive circuit 64. The regenerated power supply unit 76 has a regenerated diode 761, which is connected to the discharge resistor 65 and outputs the DC current of the regenerated electricity to the first step-down circuit 73. Thus, the regenerated electricity can be flexibly utilized as power for driving the power-on control circuit 74. Therefore, when the regenerated electricity is used again, it can be effectively and flexibly utilized with a simple structure while eliminating the complex circuits and controls of the past. As a result, the control device 3 can be driven with low power consumption.

[0076] Furthermore, the robot system 100 includes a robot 1 with a robotic arm 10 and a control device 3 for controlling the drive of the robotic arm 10. This allows regenerated power to be flexibly utilized as power for the drive of the power control circuit 74. Therefore, while omitting the circuitry for discharge control that matches the timing of power consumption, regenerated power can be effectively and flexibly utilized with a simple configuration. As a result, the control device 3 can be driven with low power consumption, achieving energy savings from the perspective of the robot system 100 as a whole.

[0077] Furthermore, the input terminal of the regenerative diode 761 in the regenerative power supply unit 76 is connected between the first converter circuit unit 62 and the discharge resistor unit 65, and the output terminal of the regenerative diode 761 is connected to the input terminal of the first step-down circuit unit 73. This allows the regenerative power generated by motors M1 to M6 to be supplied to the first step-down circuit unit 73 simultaneously. It should be noted that the input side of the regenerative diode 761 can also be connected to the drive circuit unit 64 or its input side. In this case, it is preferable to provide a regenerative diode 761 corresponding to each of motors M1 to M6.

[0078] Next, the relationship between the voltage value A of the current input to the first step-down circuit section 73 and the threshold value B of the voltage value of the regenerated power of motors M1 to M6 will be explained.

[0079] The voltage value A of the current input to the first step-down circuit section 73 is preferably less than the threshold value B. This allows for a lower frequency of voltage application to the discharge resistor section 65, and an increase in the frequency of regenerated power supply to the power-on control circuit section 74. Therefore, regenerated power can be utilized more effectively and flexibly.

[0080] In addition, due to individual differences in components, the voltage value A has an amplitude, i.e., a specified range.

[0081] The central value of voltage value A is A3, with A3 as the center, the minimum value is A1, and the maximum value is A2. It should be noted that the setting value set by the output voltage setting resistor 721 of the power factor improvement circuit section 72 is the central value A3. For example, A1 is set to 370V or higher and approximately 380V. A2 is set to 385V or higher and approximately 395V.

[0082] In addition, due to individual differences in components, the threshold B also has a range, i.e., a defined range.

[0083] The central value of threshold B is B3, with B3 as the center, a minimum value of B1, and a maximum value of B2. It should be noted that the setpoint for the comparator power supply voltage of comparator 68 is the central value B3. Therefore, the accuracy of the comparator power supply voltage is preferably less than 5%. Furthermore, due to the resistance error of resistors R1 to R4 in comparator 68, threshold B deviates from the central value B3. By increasing the resistance accuracy of resistors R1 to R4, the minimum value B1 can be increased, and the maximum value B2 can be decreased. Therefore, the resistance accuracy of resistors R1 to R4 is preferably less than 1%. For example, B1 is set to 390V or higher and approximately 400V. B2 is set to 415V or higher and approximately 425V.

[0084] By ensuring that these voltage values ​​satisfy the following relationship, the following effects can be obtained respectively.

[0085] 1. The relationship that satisfies A1 < B1 < A3 < A2 < B2 is (refer to...) Figure 4 ).

[0086] Therefore, a region can be formed where the range of voltage value A and the range of threshold B do not overlap. Consequently, the frequency of supplying regenerated power to the power-on control circuit section 74 can be increased, enabling more efficient and flexible utilization of regenerated power.

[0087] 2. Satisfying the relationship A1 < A3 < B1 < A2 < B2 (refer to...) Figure 5 ).

[0088] This allows for a further expansion of the non-overlapping range of voltage value A and threshold B. Consequently, it enables a further increase in the frequency at which regenerated power is supplied to the power-on control circuit 74, allowing for more efficient and flexible utilization of regenerated power.

[0089] It should be noted that when the range of voltage value A and the range of threshold B overlap, components such as the resistor of the discharge resistor section 65 and the regenerative capacitor 63 can use low-cost components.

[0090] 3. The relationship that satisfies A2≤B1 (refer to...) Figure 6 ).

[0091] Therefore, the region where the range of voltage value A and the range of threshold B do not overlap can be expanded as much as possible. Consequently, the frequency of supplying regenerated power to the power-on control circuit 74 can be further increased, allowing for more efficient and flexible utilization of regenerated power. In this case, it is preferable that the difference between A2 and B1 be as small as possible.

[0092] In this way, the voltage value A and the threshold B have a defined range. When the maximum value of voltage value A is set as A2, the central value which is the center of the defined range of voltage value A is set as A3, and the minimum value of threshold B is set as B1, it is preferable to satisfy the relationship A3 < B1 < A2. This further expands the area where the ranges of voltage value A and threshold B do not overlap. Therefore, the frequency of supplying regenerated power to the power-on control circuit section 74 can be further increased, and regenerated power can be utilized more effectively and flexibly.

[0093] Furthermore, the voltage value A and the threshold B have a defined range. When the maximum value of voltage value A is set as A2 and the minimum value of threshold B is set as B1, it is preferable to satisfy the relationship A2 ≤ B1. This maximizes the area where the ranges of voltage value A and threshold B do not overlap. Therefore, the frequency of supplying regenerated power to the power-on control circuit 74 can be further increased, enabling more efficient and flexible utilization of regenerated power.

[0094] Furthermore, the power factor improvement circuit section 72 includes an output voltage setting resistor 721 for setting the voltage output to the first buck circuit section 73, and the resistance accuracy of the output voltage setting resistor 721 is preferably 1% or less. This allows for easy setting, and particularly, reduction, of A2, which is the maximum value of the voltage value A. Therefore, it helps the voltage value satisfy the relationships 1, 2, and 3 above, and the aforementioned effects can be easily obtained.

[0095] Furthermore, the control device 3 includes a comparator 68 that selects whether to supply power to the discharge resistor section 65 based on a threshold B, and the resistance accuracy of the comparator 68 is 1% or less. Therefore, it is easy to set, and in particular to increase, the minimum value of the threshold B. This helps to satisfy the relationships 1, 2, and 3 above, and the aforementioned effects can be easily obtained.

[0096] It should be noted that in this embodiment, the control circuit 10A has a power factor improvement circuit section 72, but as a variation, it may also be as follows: Figure 7 The configuration shown does not include a power factor correction circuit 72. In this case, the first buck converter 73 is connected to the second converter circuit 71. Furthermore, the output terminal of the regenerative diode 761 of the regenerative power supply unit 76 is connected between the second converter circuit 71 and the first buck converter 73. The first buck converter 73 is a DC / DC converter with a flyback mechanism or similar. In this configuration, the regenerative power can also be flexibly utilized as driving power for the power control circuit 74.

[0097] The control device and robot system of the present invention have been described above with reference to the illustrated embodiments, but the present invention is not limited thereto. Furthermore, the various parts of the control device and robot system can be replaced with any structure that performs the same function. Additionally, any arbitrary structure may be added.

Claims

1. A control device characterized by comprising: A control device that controls driving of a motor of a robot arm includes: a terminal that is supplied with electric power from an alternating-current power supply; a plurality of input and output terminals that input and output electric power to and from the motor; a first converter circuit section that converts alternating-current current input from the terminal into direct-current current and outputs the direct-current current; a drive circuit section that converts the direct-current current output from the first converter circuit section into alternating-current current and outputs the alternating-current current to the plurality of input and output terminals and that is input with regenerative electric power from the motor from the plurality of input and output terminals; a discharge resistor section that is connected in parallel to the drive circuit section and that is input with the regenerative electric power from the drive circuit section and that consumes electric power in a case where a voltage value of the regenerative electric power exceeds a threshold value; a second converter circuit section that is connected in parallel to the first converter circuit section and that converts alternating-current current input from the terminal into direct-current current and outputs the direct-current current; a first voltage reduction circuit section that reduces and outputs a voltage of current output from the second converter circuit section; a current supply control circuit section that operates using direct-current current output from the first voltage reduction circuit section and that controls the drive circuit section; and a regenerative electric power supply section that has a regenerative diode that is connected to the discharge resistor section and that outputs direct-current current of the regenerative electric power to the first voltage reduction circuit section, a voltage of current input to the first voltage reduction circuit section is less than the threshold value, the voltage and the threshold value have a prescribed range, in a case where a maximum value of the voltage is set to A2, a central value that is a center of the prescribed range of the voltage is set to A3, and a minimum value of the threshold value is set to B1, a relationship of A3 A control device that controls driving of a motor of a robot arm includes:

2. A control device characterized by comprising: a terminal that is supplied with electric power from an alternating-current power supply; a plurality of input and output terminals that input and output electric power to and from the motor; a first converter circuit section that converts alternating-current current input from the terminal into direct-current current and outputs the direct-current current; a drive circuit section that converts the direct-current current output from the first converter circuit section into alternating-current current and outputs the alternating-current current to the plurality of input and output terminals and that is input with regenerative electric power from the motor from the plurality of input and output terminals; a discharge resistor section that is connected in parallel to the drive circuit section and that is input with the regenerative electric power from the drive circuit section and that consumes electric power in a case where a voltage value of the regenerative electric power exceeds a threshold value; a second converter circuit section that is connected in parallel to the first converter circuit section and that converts alternating-current current input from the terminal into direct-current current and outputs the direct-current current; a first voltage reduction circuit section that reduces and outputs a voltage of current output from the second converter circuit section; a current supply control circuit section that operates using direct-current current output from the first voltage reduction circuit section and that controls the drive circuit section; and a regenerative electric power supply section that has a regenerative diode that is connected to the discharge resistor section and that outputs direct-current current of the regenerative electric power to the first voltage reduction circuit section, a voltage of current input to the first voltage reduction circuit section is less than the threshold value, the voltage and the threshold value have a prescribed range, in a case where a maximum value of the voltage is set to A2, a central value that is a center of the prescribed range of the voltage is set to A3, and a minimum value of the threshold value is set to B1, a relationship of A3 ​ When the maximum value of the voltage is set as A2 and the minimum value of the threshold value is set as B1, a relationship of A2≤B1 is satisfied.

3. The control device according to claim 1 or 2, characterized in that The terminal of the input side of the regenerative diode of the regenerative power supply section is connected between the first converter circuit section and the discharge resistance section, and the terminal of the output side of the regenerative diode is connected to the input side terminal of the first step-down circuit section.

4. The control device according to claim 1 or 2, characterized in that The control device is provided with a power factor improvement circuit section that improves the power factor of the power supplied from the regenerative power supply section and outputs to the first step-down circuit section.

5. The control device according to claim 4, characterized in that The power factor improvement circuit section has an output voltage setting resistance that sets the voltage output to the first step-down circuit section, The resistance accuracy of the output voltage setting resistance is 1% or less.

6. The control device according to claim 1 or 2, characterized in that The control device is provided with a comparator that selects whether or not to supply power to the discharge resistance section based on the threshold value, The resistance accuracy of the resistance of the comparator is 1% or less.

7. A robot system, characterized by provided with: a robot having a robot arm; and the control device according to any one of claims 1 to 6, which controls driving of the robot arm.

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