JP4996577B2 - Electric power supply system with output limiting function for simple installation type robot and simple installation type robot equipped with the system - Google Patents

Description

  The present invention relates to an electric power having a plurality of operation modes having different motor output levels as an output limiting function for a movable simple installation type robot having a work arm and a carriage and capable of coexisting with a human. It relates to the supply system.

  Conventionally, when a direct current (DC) power source is used as a motor driving power source in an industrial robot having a multi-axis motor (hereinafter referred to as a robot), for example, AC-DC conversion from a commercial alternating current (AC) power source in a factory. A DC power source is obtained through a power supply device having a circuit.

  Industrial robots that frequently perform stop, acceleration, and deceleration operations have motor peak current values that are considerably larger than current values during normal operation. Further, if the tact time is to be shortened, the robot is accelerated and decelerated in a faster cycle, and therefore a larger motor peak current is required.

  At this time, the power conversion circuit alone cannot sufficiently supply the motor peak current necessary for producing a speed larger than the safe limit speed of the robot. On the other hand, although the battery has a current capacity sufficient to supply the motor peak current, it cannot be expected to supply power for a long time by itself.

  Furthermore, a robot capable of coexisting with humans is required to have safety that does not damage humans. In particular, when the output of the motor of each axis of the robot exceeds 80 W, it is necessary to take measures such as providing a safety fence so as to prevent a person from approaching the robot based on safety standards defined by laws and regulations. For this reason, it is necessary to prevent the robot from having a large output power, or to provide a control system for keeping the output power small so as not to damage humans even if it has a large output power. Become.

  Therefore, the present invention is a power supply system having a plurality of operation modes with different motor output levels, which can be used as a power source for a robot that can cooperate and coexist with humans, while realizing a large motor peak current. On the other hand, by adjusting the power that can be output according to the required degree of safety (operation mode), the robot power supply system can be compatible without compromising the safety and usefulness of the robot. The purpose is to obtain.

In order to solve this problem, a power supply system for a robot according to the present invention is provided in the vicinity of a simple installation type multi-axis robot, and detects the presence of an obstacle including a human around the multi-axis robot. In order to control the output power of the motor that drives each axis of the multi-axis robot based on the presence or absence of the obstacle, a plurality of operation modes with different motor output levels are switched. A power supply system for a robot, wherein two power conversion circuits for obtaining DC power as drive power of the motor from a commercial AC power source, a battery that can be charged from the power conversion circuit, and the detection signal in the normal operation mode that did not receive, the maximum output obtained by adding the output from the battery to the output from the two power conversion circuit, receiving said detection signal For output limit mode took, the output from only the two power conversion circuit, have a switching means for switching so as to supply to the motor, in the case of the normal operation mode, the multi-axis robot In operation at a speed less than the safety limit speed, which is a speed that does not require a larger current, the battery is not consumed and the outputs from the two power conversion circuits are used, and the battery is in a floating charge state. To .
Preferably, the robot power supply system of the present invention includes a protection stop switch that outputs a protection stop command signal, and the normal operation mode is a case where the detection signal and the protection stop command signal are not received, In the protection stop mode in which the protection stop command signal is received, the switching means switches so that the output from only one of the two power conversion circuits is supplied to the motor.

  In this way, a commercial AC power supply is used as the basic power supply, and in an operation mode with a large output level, a special power supply is specially provided by supplementarily supplying the output from the battery charged during the operation mode with a low output level. Without providing, a large motor peak current can be supplied by a simple method in an environment where an existing simple installation robot is promoted.

  As the operation mode, for example, a normal operation mode, an output restriction mode, and a protection stop mode are provided. For example, when there are no humans around the robot and the robot can be operated at the maximum output, the normal operation mode is selected, and there are obstacles such as humans around the robot. In the state where the limit is required, the output limit mode is used. When the most safety is required, the control circuit is operated and the motor is stopped. Operate according to the required safety level.

Preferably, the robot power supply system of the present invention, a control circuit for operating the two relay circuit is a switching means, the control circuit of two power conversion circuit and the battery by the two relay circuit A plurality of operation modes are realized by parallelly connecting and disconnecting the outputs.

  With this configuration, a plurality of operation modes can be controlled by a simple method without complicating the control circuit.

Here, the control circuit, by a configuration that uses a signal received from a sensor for detecting an obstacle existing around the multi-axis robot with the switching of the operation mode, for example, sense the human and other obstacles Therefore, the operation mode can be switched according to the situation without requiring artificial switching.

  Preferably, the control circuit has a manual changeover switch. With this configuration, when the robot is transported and moved, or for some other reason, for example, when it is necessary to artificially switch to the protection stop mode, the configuration can be easily operated from the outside.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a robot power supply system according to an embodiment of the present invention. FIG. 2 is a perspective view showing a double-arm robot as a simple installation type robot having the system of this embodiment. FIG. 3 is a circuit diagram of the power supply system shown in FIG. FIG. 4 is a flowchart of the power supply system shown in FIG.

  The robot power supply system of the embodiment shown in FIG. 1 includes a control circuit 7 provided in the double-arm robot 1 shown in FIG. 2 and a separate sensor 8 provided in the vicinity of the robot. This sensor 8 is provided at an arbitrary location near the work area of the double-arm robot 1, and is a sensor that detects a human or other obstacle around the double-arm robot 1, such as a curtain sensor, a mat sensor, or an infrared sensor. And When the sensor 8 detects an obstacle, it sends a signal to the control circuit of the dual-arm robot 1 by wire or wirelessly to notify that there is a human or other obstacle approaching the vicinity of the dual-arm robot 1.

  The double-arm robot 1 includes a torso 2, a head 3 provided at the upper end of the torso 2, two arms 4 positioned on the left and right sides of the torso 2 as viewed from the robot itself, A sandwich-type hand 5 as an example of an end effector provided at the tip, and a carriage 6 that supports the lower portion 2a of the body 2 instead of legs. Further, the double-arm robot 1 includes a neck pitch axis and a neck yaw axis that support the head 3, a waist yaw axis between the lower part and the upper part of the torso, a shoulder yaw axis and a shoulder that rotate the entire arm 4 with respect to the torso 2 There are a total of six movable axes including a pitch axis, a wrist pitch axis for tilting the hand 5 with respect to the lower arm 4b, and a wrist roll axis. As is well known, each of these movable shafts is constituted by a rotation mechanism in which a motor 9 such as a servo motor is combined with a speed reducer such as a brand name harmonic drive.

  Further, the double-arm robot 1 includes a control box 16 mounted on the lower portion of the carriage 6 and having a control circuit 7 having a normal computer.

  FIG. 3 is a block diagram of the robot power supply system of this embodiment. As can be seen from the above, the control circuit 7 includes a robot control arithmetic unit 17 including a central processing unit (CPU) for controlling the operation of each of the movable axis drive circuits of the double-arm robot 1, and this also includes a CPU. And an arithmetic unit 18 for controlling a relay circuit. Further, the control box 16 includes a first power conversion circuit (AC-DC converter) 19 and a second power conversion circuit 20 for obtaining DC power as drive power for the motors of the respective axes from a commercial AC power source, for example, a lead battery. , A charging circuit 22 for charging the battery 21, two power conversion circuits 19 and 20, and a first relay circuit 25 and a second relay circuit 26 that control ON / OFF of the current from the battery 21. And are provided. At this time, the first relay circuit 25 connects and disconnects the DC power output obtained from the first power conversion circuit 19 and the DC power output obtained from the second power conversion circuit 20 in parallel. On the other hand, the second relay circuit 26 connects and disconnects the DC power output obtained from both power conversion circuits 19 and 20 and the DC power output obtained from the battery 21 in parallel.

  The carriage 6 is provided with a handle 23 at the rear thereof so that it can be pushed and pulled by hand, and a switch box 24 is detachably attached to the handle 23. 1 emergency stop switch 27 and protective stop switch 28 are provided. Each of these switches 27 and 28 is connected to the control circuit 7 in the control box 16.

  FIG. 4 is a flowchart showing how the power supply system of the present invention switches the operation mode. At this time, when the relay circuit control arithmetic unit 18 receives no signal from either the protection stop switch 28 or the sensor 8, the system enters the normal operation mode (S7), and the stop command from the protection stop switch 28 When the signal is received (S1), the protection stop mode is entered (S2). When the signal from the sensor 8 is received (S4), the mode is switched to the output restriction mode (S5).

[Normal operation mode]
In the normal operation mode, the relay circuit control arithmetic unit 18 turns on both the relay circuits 25 and 26 (S8a). At this time, the battery output path and the output paths from both power conversion circuits are all connected, and the maximum power can be supplied to the double-arm robot 1. Therefore, the robot control arithmetic unit 17 can give a trajectory command that can use the maximum output of the robot (S8b).

  However, even in the same mode, when operating at a speed at which the double-arm robot 1 does not require a larger current (in this embodiment, a speed lower than the safe limit speed), the battery is consumed due to the difference in voltage. Instead, the outputs from both power conversion circuits 19 and 20 are used (S10). At this time, the battery 21 is in a floating charge state.

  When the double-arm robot 1 operates at a high speed, a larger current is required, so that the output voltages from both the power conversion circuits 19 and 20 temporarily drop. When this voltage becomes lower than the battery voltage, current flows out from the battery, and corresponds to a large current value instantaneously at the peak (S11). When the peak state is passed and no large current is required, the voltage drop state returns to the original output voltage, and the outputs from both power conversion circuits 19 and 20 are used again. In this way, since electric power is supplied to the double-arm robot 1 without interruption, it does not hinder its operation.

[Output restriction mode]
When the relay circuit control arithmetic unit 18 receives a signal indicating that a human is present around the robot from the sensor 8 or the like (S4), the relay circuit control unit 18 switches the relay circuits 25 and 26 to the output restriction mode (S5). In the relay circuit, by turning off the battery side path, only the power generated by the power conversion circuits 19 and 20 is supplied to the robot (S6a). At the same time, the robot control processing unit 17 also gives a gentle robot trajectory command for the output restriction mode to the double-arm robot 1 (S6b). At this time, even if a malfunction occurs in the arithmetic unit for controlling the relay circuit and a command exceeding the safe limit speed of the robot is output, the output of the power is limited, so that the robot cannot output a speed higher than the safe speed. And safety can be maintained.

[Protection stop mode]
When the relay circuit control arithmetic unit 18 detects a protection stop command from a protection stop switch or the like (S1), the relay circuits 25 and 26 are switched to the protection stop mode (S2), and the motor 9 is stopped while operating the control system. . In the relay circuits 25 and 26, both the relay circuits are turned off to turn off the second power conversion circuit 29 and the path on the battery 21 side, and the first power conversion circuit 19 generates the two-arm robot 1. Only the remaining power is supplied (S3a). At the same time, the robot control processing unit 17 also gives a robot stop command for protection stop mode to the double-arm robot (S3b). Even if a malfunction occurs in the arithmetic unit for controlling the relay circuit and an operation command is output to the robot, the robot can only output the minimum speed due to the power output limit, minimizing the danger. .

  For consumption of the battery 21, the battery is charged from the power conversion circuit side regardless of the mode.

  The examples described above with the drawings are merely examples of the embodiments of the present invention, and those skilled in the art will be able to consider various modifications within the scope of the claims of the present invention. For example, the protection stop switch 28 may be disposed at a position where it is easy to operate from an employee, for example, in the workplace, or not at the switch box of the robot. In this case, signals are transmitted by wired or wireless communication.

  Thus, according to the robot power supply system of the present invention, a commercial AC power supply is used as a basic power supply, and in an operation mode with a high output level, power is supplementarily supplied from a battery charged during the operation mode with a low output level. Thus, a large motor peak current can be supplied by a simple method in an environment where an existing simple installation robot is promoted without providing a special power supply.

It is a figure which shows the structure of the electric power supply system for robots which is one Example of this invention. It is a perspective view which shows the double arm robot as a simple installation type robot which provides the electric power supply system for robots of the Example shown in FIG. It is a circuit diagram of the electric power supply system shown in FIG. It is a flowchart of the electric power supply system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Two-arm robot 2 Body 2a Lower part 3 Head 4 Arm 4b Lower arm 5 Hand 6 Cart 7 Control circuit 8 Sensor 9 Motor 16 Control box 17 Arithmetic device 18 for robot control 18 Arithmetic device 19 for relay circuit control First power conversion circuit 20 2 Power conversion circuit 21 Battery 22 Charging circuit 23 Handle 24 Switch box 25 First relay circuit 26 Second relay circuit 27 Emergency stop switch 28 Protection stop switch

Claims (5)

Based on the presence or absence of the obstacle, the sensor is provided in the vicinity of a simple installation type multi-axis robot, detects the presence of an obstacle including a human around the multi-axis robot, and outputs a detection signal. A power supply system for a robot that switches a plurality of operation modes having different motor output levels in order to control output power of a motor that drives each axis of the multi-axis robot,
Two power conversion circuits for obtaining DC power as drive power of the motor from a commercial AC power source;
A battery that can be charged from the power conversion circuit;
In the normal operation mode in which the detection signal has not been received, the maximum output obtained by adding the output from the battery to the output from the two power conversion circuits, and in the output restriction mode in which the detection signal has been received, the output from only two of the power conversion circuit, have a switching means for switching so as to supply to the motor,
Even in the normal operation mode, in the operation at a speed equal to or lower than the safety limit speed, which is a speed at which the multi-axis robot does not require a larger current, the two power conversions are performed without consuming the battery. A power supply system for a robot that uses an output from a circuit to place the battery in a floating charge state . The robot power supply system according to claim 1,
A protective stop switch is provided to output a protective stop command signal.
The normal operation mode is a case where the detection signal and the protection stop command signal are not received,
The switching means is
For protection stop mode having received the protective stop command signal, the two of power conversion circuit robot power supply system and switches to provide an output from one only to the motor of the . The robot power supply system according to claim 1 or 2,
Comprising a control circuit for operating the two relay circuit is before Symbol switching means,
The control circuit realizes the plurality of operation modes by connecting and disconnecting the outputs from the two power conversion circuits and the battery in parallel by the two relay circuits. system. In the robot power supply system according to claim 3,
The robot power supply system, wherein the control circuit has a manual changeover switch.   A movable simple installation type robot comprising the power supply system for a robot according to any one of claims 1 to 4.

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