Robot control device

Abstract

This reduces the possibility of power circuit malfunctions occurring during robot operation. [Solution] The robot control device 4 comprises a servo amplifier 11 that controls each motor of the robot 1, a power supply circuit 14 that supplies power to the servo amplifier 11, etc., a measuring unit 15 that measures the power supplied to the power supply circuit 14, and a control unit 16 that controls the servo amplifier 11 based on an operation program to operate the robot 1. In test mode, the control unit 16 operates the robot 1 at multiple speeds of 100% or less based on the operation program, and uses the power measured according to the operation to calculate the power consumption rate, which is the ratio of power consumption to rated power. If the power consumption rate corresponding to 100% speed exceeds a threshold, the control unit 16 determines the speed ratio when operating the robot 1 in actual operation mode so that the power consumption rate becomes below the threshold.

Description

Technical Field

[0001] The present invention relates to a robot control device that controls a robot having a plurality of arms connected by joints.

Background Art

[0002] Conventionally, in order to perform analysis for suppressing the power consumption of industrial robots, recording and outputting the power consumption of robots has been carried out (for example, refer to Patent Document 1).

Prior Art Literature

Patent Document

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by Invention

[0004] In recent years, collaborative robots, which are industrial robots that perform work together with humans in the same space, have come into use. This collaborative robot may, for example, operate with a single-phase 100V household AC power supply. For household AC power supplies, the rated power of the power supply is usually set to a low value such as 1500W. In addition, for collaborative robots that are assumed to be portable, there is also a demand for downsizing the power supply circuit. In response to such circumstances, low-capacity components may be used as the power supply circuit and breaker of the robot control device that supplies power to the robot. Depending on the operation of the robot, an overload abnormality or temperature rise abnormality of the power supply circuit, tripping of the breaker, and the like may occur. Since these abnormalities usually occur after a lapse of time from the start of the robot's operation, it takes time to correct the operation program after the abnormality occurs, and defective workpieces may also be generated in some cases.

[0005] Generally speaking, there was a demand to operate the robot in a way that would prevent conditions from occurring that would stop the robot, such as a malfunction in the power circuit of the robot control system or a tripped circuit breaker, during robot operation.

[0006] The present invention has been made in response to the above circumstances, and aims to provide a robot control device that can reduce the possibility of conditions occurring that would stop the robot, such as power circuit malfunctions or circuit breaker tripping, during robot operation. [Means for solving the problem]

[0007] To achieve the above objective, a robot control device according to one aspect of the present invention comprises a servo amplifier for controlling each motor in a robot having a plurality of arms connected by joints driven by motors, a storage unit for storing a robot operation program, a control unit for operating the robot by controlling the servo amplifier based on the operation program, a power supply circuit for supplying power to the servo amplifier and the control unit, and a measurement unit for measuring the power supplied to the power supply circuit. In test mode, the control unit operates the robot at a rate of 100% or less based on the operation program, calculates a power consumption utilization rate which is the ratio of power consumption to rated power using the power measured by the measurement unit according to the robot's operation, and performs a predetermined process if the power consumption utilization rate when the robot is operated at 100% exceeds a first threshold. [Effects of the Invention]

[0008] According to one aspect of the present invention, a robot control device can reduce the possibility of conditions occurring that would stop the robot during its operation, such as a power supply circuit malfunction or a circuit breaker tripping. [Brief explanation of the drawing]

[0009] [Figure 1] Block diagram showing the configuration of a robot control system according to an embodiment of the present invention. [Figure 2]Flowchart showing the operation of the robot control device according to this embodiment. [Modes for carrying out the invention]

[0010] The robot control device according to the present invention will be described below using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent and may not be described again. The robot control device according to this embodiment operates the robot at multiple speeds of 100% or less based on an operation program in test mode, calculates the power consumption rate, which is the ratio of power consumption to rated power, using the power measured according to the operation of the robot, and performs predetermined processing to prevent the power consumption rate in actual operation mode from exceeding the first threshold when the power consumption rate when the robot is operated at 100% speed exceeds a first threshold.

[0011] Figure 1 is a block diagram showing the configuration of the robot control system 100 according to this embodiment. The robot control system 100 comprises a robot 1, an AC power supply 2, a teaching pendant (TP) 3, and a robot control device 4. If other equipment, such as a positioner or a travel axis, is also controlled by the robot control device 4 along with the robot 1, the robot control system 100 may further include those devices.

[0012] Robot 1 may be a robot having multiple arms connected by motor-driven joints. Robot 1 may be an industrial robot such as a transport robot, welding robot, assembly robot, or painting robot. Robot 1 may also be a collaborative robot, for example. Robot 1 may also be a vertical articulated robot, a horizontal articulated robot, or any other type of robot. Robot 1 may have end effectors at the ends of its multiple arms, depending on the application of Robot 1. For example, if Robot 1 is a welding robot, the end effector may be a welding torch. As another example, if Robot 1 is a transport robot or assembly robot, the end effector may have a gripping part for gripping the object to be transported or assembled. If Robot 1 is a welding robot, the robot control system 100 may further include equipment necessary for welding, such as a welding power supply that supplies high voltage to the welding torch and workpiece, and a wire feeding device that feeds welding wire.

[0013] AC power supply 2 supplies power to the robot control device 4. AC power supply 2 may be, for example, a commercial power supply. AC power supply 2 may be, for example, a three-phase AC power supply or a single-phase AC power supply. For example, when the robot control device 4 controls robot 1, which is a collaborative robot, AC power supply 2 may be a single-phase 100V household outlet or a single-phase 200V AC power supply. As another example, AC power supply 2 may be a three-phase 200V distribution board. In this embodiment, as an example, the case in which power is supplied to the robot control device 4 from AC power supply 2 will be mainly described, but power may be supplied to the robot control device 4 from other power sources.

[0014] The teaching pendant 3 is used, for example, to input, modify, and register the motion program for robot 1, to input instructions such as starting playback operations related to robot 1, and to output information related to robot 1. However, if the input of the robot 1's motion program and other processing are performed by a device other than the teaching pendant 3, such as a computer or tablet terminal, the robot control system 100 does not need to be equipped with the teaching pendant 3.

[0015] The robot control device 4 controls the robot 1 and includes a servo amplifier 11, a memory unit 12, a circuit breaker 13, a power supply circuit 14, a measurement unit 15, and a control unit 16.

[0016] The servo amplifier 11 controls each motor in the robot 1. Therefore, the angle of each joint of the robot 1 is controlled by the servo amplifier 11. This control may be performed, for example, by feedback control using control instructions from the control unit 16 and feedback signals such as current values ​​from each motor.

[0017] The memory unit 12 stores the operation program for the robot 1. The operation program may be, for example, teaching data generated by teaching the robot 1. The operation program may have multiple steps, for example. Each step of the operation program may be an action in the robot 1, such as moving the end effector from one position to another. The operation program may be stored in the memory unit 12 by, for example, the control unit 16, or it may be stored in the memory unit 12 via another recording medium or a communication line.

[0018] Furthermore, the storage unit 12 may store, for example, the power consumption and power consumption utilization rate for each percentage of the robot 1's speed. The storage unit 12 may also store, for example, the power consumption and power consumption utilization rate for each step of the operation program, or the power consumption and power consumption utilization rate for the entire operation program. This information may be stored in the storage unit 12 by, for example, the control unit 16. The storage unit 12 may also store the first and second thresholds described later, as well as other information. The storage unit 12 is preferably implemented using a non-volatile recording medium, but may also be implemented using a volatile recording medium. The recording medium may be, for example, a semiconductor memory or a magnetic disk.

[0019] The circuit breaker 13 is a circuit breaker that opens the circuit and cuts off the power supply when an abnormal overcurrent flows to the secondary side due to factors such as overload. The circuit breaker 13 may be, for example, a no-fuse circuit breaker. The circuit breaker 13 is usually installed between the AC power source 2 and the power supply circuit 14 to protect the power supply circuit 14, etc.

[0020] The power supply circuit 14 supplies power to the servo amplifier 11 and the control unit 16. Since the robot 1 is operated by the servo amplifier 11, the power supply circuit 14 is supplying power to the robot 1. Furthermore, if other equipment such as positioners and travel axes are also controlled by the robot control device 4, the power supply circuit 14 may also supply power to those equipment. The power supply circuit 14 may convert the AC power supplied from the AC power supply 2 into a predetermined DC power and supply it to the servo amplifier 11 and the control unit 16. For example, the servo amplifier 11 may be supplied with DC 280V DC power. Also, for example, the control unit 16 may be supplied with DC 24V DC power. Needless to say, the servo amplifier 11 and the control unit 16 may also be supplied with DC power of a different voltage.

[0021] The measurement unit 15 measures the power supplied to the power supply circuit 14. As shown in Figure 1, the measurement unit 15 may, for example, measure the current and voltage flowing through the power line between the breaker 13 and the power supply circuit 14, and calculate the power using the measured current and voltage.

[0022] The control unit 16 operates the robot 1 by controlling the servo amplifier 11 based on the operation program stored in the storage unit 12. The control unit 16 may operate the robot 1, for example, by performing playback control using the operation program. When the robot control system 100 includes other devices such as a positioner and a traveling axis, the control unit 16 may also control those devices. That is, the operation of the robot 1 by the control unit 16 may mean that the control unit 16 also operates other devices such as a positioner and a traveling axis attached to the robot 1. Note that a mode in which the robot 1 performs a target operation (for example, operations such as conveyance, welding, and assembly) on a workpiece or the like based on the operation program is referred to as a "actual operation mode". On the other hand, a mode in which the power consumption usage rate corresponding to the operation program is checked and predetermined processing is performed to prevent the power consumption usage rate from exceeding the first threshold value is referred to as a "test mode". Hereinafter, this test mode will be described.

[0023] In a test mode, the control unit 16 causes the robot 1 to operate at a plurality of speeds each at a ratio of 100% or less based on the operation program stored in the storage unit 12. In the test mode, measurement of power consumption during operation of the robot 1, check of whether the power consumption usage rate exceeds a first threshold value, and the like are performed. When operating the robot 1 in the test mode, since it is only required that each joint of the robot 1 is operated, actual processing on a workpiece may or may not be performed. For example, when the robot 1 is a welding robot, welding does not have to be performed in the test mode. On the other hand, for example, when the robot 1 is a transfer robot and the weight of a transfer target object is large, the power consumption of the robot 1 may differ depending on whether the robot 1 transfers the transfer target object, so actual transfer may be performed even in the test mode. Note that the robot control system 100 also includes other devices such as a positioner and a travel axis, and in a case where power is supplied to these devices from the power supply circuit 14, it is preferable that these devices are also operated in accordance with the operation program in the test mode. The control unit 16 may, for example, cause the robot 1 to operate at a plurality of predetermined speed ratios. This operation may be referred to as "test operation". As an example, the control unit 16 may cause the robot 1 to operate at each of the speed ratios of 10%, 30%, 50%, 70%, and 100%. The speed ratio may be a ratio of a speed to the maximum speed. Therefore, for example, when the speed ratio is 100%, the robot 1 operates at the maximum speed. It goes without saying that the control unit 16 may cause the robot 1 to operate at speed ratios other than these in the test mode. As another example, the control unit 16 may cause the robot 1 to operate at each of the speed ratios of 20%, 40%, 60%, 80%, and 100%. Further, for a step in which the moving speed of the end effector is preset in the operation program, the control unit 16 does not need to change the speed ratio, for example. The step in which the moving speed of the end effector is preset may be, for example, a step of performing welding.

[0024] Furthermore, the control unit 16 calculates the power consumption rate, which is the ratio of power consumption to rated power, using the power measured by the measurement unit 15 according to the movement of the robot 1. The power consumption rate is calculated for each speed ratio. The control unit 16 may, for example, calculate the power consumption rate for each step if the operation program includes multiple steps. Regardless of whether the power consumption rate is calculated for each step, the control unit 16 may calculate the power consumption rate corresponding to the entire operation program.

[0025] The power consumption rate may be calculated, for example, by the following formula. In the following formula, the measured power consumption is the power consumption measured by the measurement unit 15. Also, the rated power consumption of the power supply circuit 14 in the following formula may be stored in the memory unit 12, for example. For example, the rated power consumption may be determined as 1350W. Power consumption rate = (Measured power consumption) / (Rated power consumption of power supply circuit 14)

[0026] The measured power consumption may be, for example, the average value of the measured power consumption. For example, when calculating the power utilization rate for the entire operating program or for a particular step of the operating program, the control unit 16 may calculate the power utilization rate for the entire operating program or for a particular step of the operating program by dividing the average power consumption for the entire operating program or the average power consumption for a particular step of the operating program by the rated power consumption. Alternatively, the average power consumption may be calculated by, for example, dividing the amount of power consumed for the entire operating program or for a particular step by the time taken for the operation of the entire operating program or that step. Information used to calculate the power utilization rate, such as measured power consumption or amount of power consumed, may be temporarily stored in the storage unit 12.

[0027] Furthermore, the control unit 16 performs a predetermined process if the power consumption rate when the robot 1 is operated at 100% speed exceeds a first threshold. Note that if the power consumption rate when the robot 1 is operated at 100% speed does not exceed the first threshold, the control unit 16 may operate the robot 1 at 100% speed in the actual operating mode. Here, the power consumption rate compared with the first threshold may be, for example, the total power consumption rate of the operation program. This predetermined process may be, for example, a process to ensure that the total power consumption rate of the operation program does not exceed the first threshold in the actual operating mode. In this embodiment, the case in which this predetermined process is a process to determine the speed ratio when operating the robot 1 based on the operation program in order to ensure that the total power consumption rate of the operation program is less than or equal to the first threshold will be mainly described, and other cases will be described later. In the actual operating mode, the control unit 16 operates the robot 1 at the speed ratio determined in this way. As a result, in the actual operating mode, the robot 1 can be operated so that the total power consumption rate of the operation program is less than or equal to the first threshold.

[0028] Preferably, the first threshold is set so that when the robot 1 is operated in such a way that the power consumption utilization rate is below the first threshold, no overload abnormalities or temperature rise abnormalities occur in the power supply circuit 14, and the circuit breaker 13 does not trip. In other words, the first threshold may be set according to experience, for example, to prevent abnormalities in the power supply circuit 14 or tripping of the circuit breaker 13. Alternatively, the first threshold may be set so that, for example, when the robot 1 is operated in such a way that the power consumption utilization rate is below the first threshold, the rated power of the AC power supply 2 does not exceed the rated power. As an example, the first threshold may be a value such as 90%.

[0029] Here, for example, if the power consumption rate has already exceeded the first threshold when robot 1 is operating at a speed less than 100% (for example, 50% or 70%), it is obvious that the power consumption rate will exceed the first threshold when robot 1 is operated at 100% speed. Therefore, it is possible to determine that the power consumption rate when robot 1 is operated at 100% speed exceeds the first threshold without actually operating robot 1 at 100% speed. Accordingly, the control unit 16 may, for example, in test mode, operate robot 1 in order from the smallest speed percentage, and if the power consumption rate corresponding to the entire operation program exceeds 100%, it may not need to operate robot 1 for subsequent speed percentages. Specifically, in test mode, when operating robot 1 at speed percentages of 10%, 30%, 50%, 70%, and 100%, if the power consumption rate corresponding to the entire operation program exceeds 100% when operating at a speed percentage of 50%, then robot 1 does not need to be operated at speed percentages of 70% and 100%. By doing so, the possibility of malfunctions in the power supply circuit 14 or tripping of the breaker 13 in test mode can be reduced.

[0030] The process of determining the speed ratio when operating the robot 1 based on the operation program in order to keep the power consumption usage below a first threshold may be, for example, (1) a process of determining the speed ratio of the operation program to the whole when operating the robot 1 in order to keep the power consumption usage below a first threshold, or (2) a process of determining the speed ratio for each of the multiple steps in the operation program when operating the robot 1 in order to keep the power consumption usage below a first threshold. The following describes each of (1) and (2) in more detail. The control unit 16 may, for example, store the determined speed ratio in the storage unit 12, or set it in the operation program stored in the storage unit 12.

[0031] (1) When determining the ratio of the speed to the overall operating program In this case, the control unit 16 may determine the overall speed ratio of the operation program to be the largest speed ratio among the speed ratios corresponding to power consumption usage rates below a first threshold obtained in the test operation. For example, if test operations are performed for speed ratios of 10%, 30%, 50%, 70%, and 100%, and the power consumption usage rates corresponding to each of the speed ratios of 10%, 30%, 50%, and 70% are below the first threshold, the control unit 16 may determine the overall speed ratio of the operation program used to operate the robot 1 in actual operation mode to be 70%, which is the largest speed ratio among those speed ratios. In this case, in actual operation mode, the entire operation program, for example, all steps in the operation program, will be operated at a speed ratio of 70%. In this case as well, for steps in the operation program where the movement speed of the end effector is predetermined, the control unit 16 may, for example, move the end effector at the predetermined speed in actual operation mode. When a percentage of the overall speed of an operating program is determined, that percentage is usually less than 100%.

[0032] (2) When determining the rate of each step of the operating program In this case, the control unit 16 may, for example, determine for each step of the operation program that the largest speed ratio among the speed ratios corresponding to a power consumption utilization rate below a first threshold obtained in the test operation is the speed ratio for that step of the operation program. For example, for the first step of the operation program, test operations are performed for speed ratios of 10%, 30%, 50%, 70%, and 100%, and if the power consumption utilization rates corresponding to each of the speed ratios of 10%, 30%, 50%, and 70% are below the first threshold, the control unit 16 may determine the speed ratio for the first step of the operation program used to operate the robot 1 in actual operation mode to be 70%, which is the largest speed ratio among those speed ratios. The control unit 16 may similarly determine the speed ratio for the second step and subsequent steps. It is self-evident that by determining the speed ratio for each step in such a way that the power consumption utilization rate is below the first threshold, the overall power consumption utilization rate of the operation program will also be below the first threshold. In this case, in the actual operating mode, each step of the operating program will be executed at the rate determined in this manner.

[0033] Furthermore, as another example, the control unit 16 may determine the speed ratio for each of the multiple steps in the operation program so that the overall power consumption utilization of the operation program is below a first threshold, and the total time from the start to the end of the operation of the robot 1 corresponding to the entire operation program is minimized. By determining the speed ratio in this way, the overall power consumption utilization of the operation program can be kept below the first threshold, and the time from the start to the end of the operation of the robot 1 in actual operating mode can be shortened. In this case, for example, the operation time of the robot 1 for each step may be measured during a test operation and stored in the storage unit 12. The speed ratio for each of the multiple steps may then be determined using these operation times as well.

[0034] Furthermore, the control unit 16 may determine the speed ratio for each step of the operation program by a method other than those described above. Even in this case, the speed ratio for each step shall be determined so that the overall power consumption rate of the operation program is less than or equal to the first threshold. When the speed ratio for each step of the operation program is determined, the determined speed ratio for each step shall be 100% or less, and usually, the speed ratio for at least one step shall be less than 100%. When the speed ratio for each step of the operation program is determined, the speed ratio for each step may differ in the operation program used for the operation of robot 1 in actual operation mode. Also, in the operation program, for steps in which the movement speed of the end effector is predetermined, the control unit 16 does not need to determine the speed ratio. That is, in the operation program, for steps in which the movement speed of the end effector is predetermined, the control unit 16 may move the end effector at the predetermined speed in actual operation mode.

[0035] Furthermore, the control unit 16 may, for example, output an indication when the power measured by the measurement unit 15 exceeds a second threshold while the robot 1 is operating in actual operation mode. This output can notify the operator, for example, that there is a high possibility of an abnormality occurring in the power supply circuit 14 or a high probability of the circuit breaker 13 tripping. The second threshold may be set according to experience to a value such that when the measured power exceeds the second threshold, the possibility of an abnormality in the power supply circuit 14 or a circuit breaker 13 tripping becomes significantly higher. For example, the second threshold may be the rated power, or it may be a value such as 90% of the rated power. The fact that the measured power has exceeded the second threshold may be output to, for example, the teaching pendant 3, the robot 1, or other devices. If the fact that the measured power has exceeded the second threshold is output to the teaching pendant 3, the teaching pendant 3 may output to the operator, for example, that the measured power has exceeded the second threshold. This output may be provided, for example, by displaying it on a monitor, outputting sound, or illuminating a warning light. If the robot 1 is notified that the measured power has exceeded the second threshold, the robot 1 may output to the operator that the measured power has exceeded the second threshold. This output may be provided, for example, by outputting sound or illuminating a warning light.

[0036] Next, the operation of the robot control device 4 will be explained using the flowchart in Figure 2. (Step S101) The control unit 16 determines whether to operate robot 1 in test mode. If it decides to operate robot 1 in test mode, it proceeds to step S102; otherwise, it proceeds to step S109. The control unit 16 may also decide to operate robot 1 in test mode if it receives an instruction from the teaching pendant 3 to operate robot 1 in test mode.

[0037] (Step S102) The control unit 16 operates the robot 1 at a predetermined rate by controlling the servo amplifier 11 based on the operation program stored in the memory unit 12. This predetermined rate does not need to be changed until a series of processes from the beginning to the end of one operation program is completed. If the operation program includes multiple steps, the operation of the robot 1 may correspond to, for example, one step.

[0038] (Step S103) The measurement unit 15 measures the power supplied to the power supply circuit 14. Although the flowchart in Figure 2 shows the case where the power is measured after the operation of the robot 1 in step S102 for the sake of explanation, the measurement unit 15 may also measure this power in parallel with the operation of the robot 1, for example in test mode. It is preferable for the measurement unit 15 to continuously measure the power in chronological order while a series of operations of the operation program are being performed by the robot 1.

[0039] (Step S104) The control unit 16 determines whether to terminate the operation of robot 1 according to the operation program. This determination may be, for example, whether to terminate a single test operation. If the operation of robot 1 is to be terminated, the process proceeds to step S105; otherwise, it returns to step S102 and continues the process of operating robot 1. The control unit 16 may also determine to terminate the operation of robot 1 when, for example, the operation of robot 1 according to the last step of a single operation program is completed.

[0040] (Step S105) The control unit 16 uses the power measurement results to calculate the power consumption utilization rate when the robot 1 is operated at a predetermined rate. The control unit 16 may also calculate the power consumption utilization rate for each step of the operation program, in addition to the overall power consumption utilization rate of the operation program. The calculated power consumption utilization rates may be stored in the storage unit 12, for example.

[0041] (Step S106) The control unit 16 determines whether all test operations have been completed. If all test operations have been completed, the process proceeds to step S107; otherwise, it returns to step S102. If the process returns to step S102, the control unit 16 may operate the robot 1 at a predetermined rate different from the previous operation, based on the operation program. In other words, if the process returns to step S102, another test operation may be performed. For example, the control unit 16 may determine that all test operations have been completed if the robot 1 has been operated at all predetermined rate percentages, and that all test operations have not been completed if there are still rate percentages at which the robot 1 has not been operated. As another example, the control unit 16 may determine that all test operations have been completed even if the robot 1 has not been operated at all predetermined rate percentages, if the overall power consumption usage rate of the operation program calculated in step S105 exceeds a first threshold.

[0042] (Step S107) The control unit 16 determines whether the power consumption rate corresponding to the entire operation program when the robot 1 is operated at 100% speed exceeds a first threshold. If the power consumption rate corresponding to the entire operation program when the robot 1 is operated at 100% speed exceeds the first threshold, the process proceeds to step S108; otherwise, it returns to step S101. For example, even if the power consumption rate corresponding to the entire operation program when the robot 1 is operated at a speed of less than 100% exceeds the first threshold, it may still be determined that the power consumption rate corresponding to the entire operation program when the robot 1 is operated at 100% speed exceeds the first threshold.

[0043] (Step S108) The control unit 16 determines the speed ratio when operating the robot 1 based on the operation program in actual operating mode, so that the power consumption utilization rate of the operation program as a whole is below a first threshold. This determined speed ratio may be stored, for example, in the memory unit 12. Then, the process returns to step S101.

[0044] (Step S109) The control unit 16 determines whether to operate the robot 1 in actual operation mode. If it decides to operate the robot 1 in actual operation mode, it proceeds to step S110; otherwise, it returns to step S101. The control unit 16 may also decide to operate the robot 1 in actual operation mode if it receives an instruction from the teaching pendant 3 to operate the robot 1 in actual operation mode.

[0045] (Step S110) The control unit 16 controls the servo amplifier 11 based on the operation program stored in the memory unit 12, thereby operating the robot 1 at the rate of speed determined in step S108. If the operation program includes multiple steps, the operation of the robot 1 may correspond to, for example, one step.

[0046] (Step S111) The measurement unit 15 measures the power supplied to the power supply circuit 14. The measurement unit 15 may continue to measure this power, for example, in the actual operating mode. This power measurement may be performed in the same manner as the power measurement in step S103.

[0047] (Step S112) The control unit 16 determines whether the power measured by the measuring unit 15 exceeds the second threshold. If the measured power exceeds the second threshold, the process proceeds to step S113; otherwise, the process proceeds to step S114.

[0048] (Step S113) The control unit 16 outputs to the teaching pendant 3 or robot 1, etc., that the measured power has exceeded the second threshold. The teaching pendant 3, etc., may then display this information to the operator, etc.

[0049] (Step S114) The control unit 16 determines whether to terminate the operation of robot 1 according to the operation program. If it decides to terminate the operation of robot 1, it returns to step S101; otherwise, it returns to step S110 and continues the process of operating robot 1. The control unit 16 may also decide to terminate the operation of robot 1 when, for example, the operation of robot 1 according to the last step of one operation program is completed.

[0050] Note that the flowchart in Figure 2 does not include the processes performed during the teaching of robot 1. Also, the order of processes in the flowchart in Figure 2 is just one example, and the order of each step may be changed if the same results can be obtained. Furthermore, in the flowchart in Figure 2, the process may be terminated by power off or processing completion interrupt.

[0051] Next, the operation of the robot control device 4 according to this embodiment will be explained using a specific example. In this example, in test mode, the robot 1 is assumed to be operated at speeds of 10%, 30%, 50%, 70%, and 100%.

[0052] First, the operator performs the teaching of robot 1 by operating the teaching pendant 3, and the following action program is stored in the memory unit 12 accordingly.

[0053] (Operating program) 0 [START] 1 100% JOINT 2 100% JOINT 3 100% JOINT 4 600cm / m LINE 5 100% JOINT 6 100% JOINT 7 END

[0054] Each step in the above-described operation program is identified by the number on the left. Hereafter, the step identified by the number "1" will be referred to as Step 1. The same applies to the other steps. In this specific example, for simplicity, we show the case where Steps 1 to 6 are steps related to the movement of the end effector. JOINT indicates that joint interpolation is performed, and LINE indicates that linear interpolation is performed. Although not explicitly stated in the above operation program, each step may also include teaching points that indicate the position of the end effector of robot 1. "100%" in Step 1, etc., of the operation program is a speed override setting and indicates a percentage of the speed. When the speed override setting is "100%", robot 1 will operate at the maximum speed. In Step 4, the movement speed of the end effector of robot 1 is specified, such as "600 cm / m". Therefore, for Step 4, the percentage of the speed will not be changed in either test mode or actual operation mode.

[0055] Next, suppose the operator inputs an instruction to operate robot 1 in test mode by operating the teaching pendant 3. This instruction is then input from the teaching pendant 3 to the robot control device 4 and received by the control unit 16. In response to receiving this instruction, the control unit 16 starts test mode (step S101). In test mode, the control unit 16 first reads the above-described operation program from the storage unit 12, sets the speed ratio of steps 1 to 3, 5, and 6 to 10%, and operates robot 1 by controlling the servo amplifier 11 according to each step in order from step 1, and receives the power measured during operation from the measurement unit 15 and stores it in the storage unit 12 (steps S102 to S104). Note that in step 4 of the operation program, the movement speed of the end effector is specified, so this movement speed is not changed even in test mode. Also, in the operation of robot 1 in test mode, for example, even if robot 1 is a welding robot, welding to the workpiece does not have to be performed. When the robot 1 completes a series of operations corresponding to a speed ratio of 10%, the control unit 16 uses the power stored in the memory unit 12 to calculate the power consumption rate for the entire operation program and for each step, and stores this calculation in the memory unit 12 (step S105).

[0056] Subsequently, the control unit 16 operates the robot 1 with a speed ratio of 30% for steps 1-3, 5, and 6, and uses the power measured by the measurement unit 15 during this operation to calculate the power consumption usage rate for the entire operation program and for each step, and stores them in the storage unit 12 (steps S106, S102-S105). The control unit 16 also performs the same process for speed ratios of 50%, 70%, and 100% (steps S106, S102-S105). Once the calculation of power consumption usage rate for each speed ratio of 10%, 30%, 50%, 70%, and 100% is complete, the control unit 16 determines whether the power consumption usage rate corresponding to the entire operation program corresponding to a speed ratio of 100% exceeds a first threshold (steps S106, S107). In this case, it is determined that the power consumption usage rate exceeded the first threshold. Then, the control unit 16 determines the speed ratio in the actual operating mode by method (1) or (2) above, and sets that speed ratio in the operation program stored in the storage unit 12 (step S108). In this specific example, let's assume that the overall speed ratio of the operation program is determined to be 70%. Then, the speed override setting for the operation program will be as follows. Note that when determining the speed ratio by method (1) above, it is not necessary to calculate the power consumption usage rate for each step of the operation program.

[0057] (Operating program) 0 [START] 1 70% JOINT 2 70% JOINT 3 70% JOINT 4 600cm / m LINE 5 70% JOINT 6 70% JOINT 7 END

[0058] Furthermore, if the power consumption rate corresponding to the entire operation program that corresponds to a speed ratio of 100% does not exceed the first threshold, the speed ratio in the actual operating mode does not need to be determined. In this case, the speed override setting of the operation program may be used as is for the operation of robot 1 in the actual operating mode without being changed. That is, in the actual operating mode, robot 1 may operate at the maximum speed.

[0059] Next, suppose the operator inputs an instruction to operate robot 1 in actual operation mode by operating the teaching pendant 3. This instruction is then input from the teaching pendant 3 to the robot control device 4 and received by the control unit 16. In response to receiving this instruction, the control unit 16 starts the actual operation mode (step S109). In actual operation mode, the control unit 16 reads the operation program after the speed override setting has been changed from the storage unit 12, operates robot 1 by controlling the servo amplifier 11 according to each step in order from step 1, receives the power measured during operation from the measurement unit 15 and determines whether the measured power exceeds a second threshold (steps S110 to S112). If the measured power exceeds the second threshold, the control unit 16 outputs a message to that effect to the teaching pendant 3 (step S113). In the operation of robot 1 in actual operation mode, for example, if robot 1 is a welding robot, welding will be performed on the workpiece. When the operation of robot 1 according to all steps of the operation program is completed, the actual operation mode ends (step S114).

[0060] As described above, according to the robot control device 4 of this embodiment, in test mode, the robot 1 is operated at multiple speeds of 100% or less, the power consumption corresponding to the operation is measured in advance, the power consumption utilization rate is calculated based on the measured power consumption, and if the power consumption utilization rate corresponding to 100% speed exceeds a first threshold, the speed ratio related to the operation program is determined, and in actual operation mode, the robot 1 is operated at the determined speed ratio, thereby reducing the possibility of malfunctions in the power supply circuit 14 or tripping of the breaker 13 during the operation of the robot 1 in actual operation mode. For example, in a robot control device 4 that operates on a single-phase 100V household AC power supply, even if the rated power of the power supply circuit 14 is set to a low value such as 1350W, and a small capacity breaker 13 is used accordingly, the possibility of malfunctions in the power supply circuit 14 or tripping of the breaker 13 during actual operation mode can be reduced. Furthermore, if the power consumption utilization rate corresponding to 100% speed exceeds the first threshold, the control unit 16 automatically determines the speed ratio in the actual operating mode, eliminating the need for operators to change the speed ratio and thus reducing the burden on operators.

[0061] Furthermore, if the speed ratio in the actual operating mode is determined to be the same value for the entire operation program, for example, by method (1) described above, the speed ratio can be determined by a simpler process. On the other hand, if the speed ratio in the actual operating mode is determined for each step of the operation program, for example, by method (2) described above, the speed of each step in the operation program can be set to a more suitable value. For example, it is possible to minimize the time during which the robot 1 operates according to the operation program while ensuring that the power consumption rate corresponding to the entire operation program is below a first threshold.

[0062] Furthermore, for steps where the movement speed of the end effector is predetermined, not changing the speed ratio allows the robot to appropriately perform the intended tasks on the workpiece in actual operation mode. For example, if the movement speed of the welding torch is determined for a welding location, not changing the movement speed of the welding torch allows the power consumption rate corresponding to the entire operation program to be kept below a first threshold, while ensuring that the robot 1 achieves welding of the desired quality.

[0063] Furthermore, when the robot 1 is operating in actual operating mode, if the measured power exceeds a second threshold, an output indicating this will be generated. This will allow operators to be notified, for example, if the robot 1 is subjected to an unexpected load, causing its power consumption to be higher than expected. Possible causes of an unexpected load on the robot 1 include, for example, the welding torch contacting the workpiece and increasing the load, or the object being transported being heavier than expected and thus increasing the load.

[0064] In this embodiment, the predetermined processing performed by the control unit 16 when the power consumption rate when the robot 1 is operated at 100% speed in test mode exceeds a first threshold is mainly described as a process that determines the speed ratio when the robot 1 is operated based on the operation program in actual operation mode so that the power consumption rate is below the first threshold, but this is not required. As another example, the predetermined processing performed by the control unit 16 when the power consumption rate when the robot 1 is operated at 100% speed in test mode exceeds a first threshold may include a process that outputs the power consumption rate for multiple speed ratios, and a process that receives an instruction to change the operation program according to the output and changes the operation program according to the instruction.

[0065] In this case, when the power consumption rate when the robot 1 is operated at 100% speed in test mode exceeds a first threshold, the control unit 16 may output the power consumption rate for each of several speed percentages to the teaching pendant 3. For example, the power consumption rate corresponding to the entire operation program for each speed percentage of 10%, 30%, 50%, 70%, and 100% may be output. Another example is that the power consumption rate for each step of the operation program corresponding to each speed percentage of 10%, 30%, 50%, 70%, and 100% may also be output. The power consumption rate output from the control unit 16 may be displayed to the operator or others on the teaching pendant 3. In this output, for example, the power consumption rate for the entire operation program or for each step may be output as a numerical value or graph.

[0066] Furthermore, the control unit 16 may receive instructions from the teaching pendant 3 to modify the operation program in accordance with its output, and modify the operation program accordingly. Instructions to modify the operation program may include, for example, instructions to change the speed ratio, or instructions to modify the operation program itself (for example, instructions to change the teaching points). For example, an operator may refer to the power consumption usage rate output by the teaching pendant 3 and input instructions to the teaching pendant 3 to change the speed ratio (speed override setting) of the entire operation program or for each step, and the control unit 16 may receive these instructions and change the speed ratio of the operation program stored in the storage unit 12 accordingly. As another example, instead of the teaching pendant 3, the control unit 16 may output the power consumption usage rate to a device such as a computer or tablet terminal connected to the robot control device 4, and receive instructions to modify the operation program from that device. In this way, by manually modifying the operation program, it is possible to change the speed ratio considering the content of the robot 1's movements, or to change the teaching points, etc. Furthermore, if the operating program is modified manually, the control unit 16 may, for example, perform the test mode processing again for the modified operating program.

[0067] Furthermore, although this embodiment mainly describes the case where the robot control device 4 is equipped with a circuit breaker 13, the robot control device 4 does not necessarily have to be equipped with a circuit breaker 13. In this case, as an example, power may be supplied to the robot control device 4 via a circuit breaker located outside the robot control device 4.

[0068] Furthermore, in the above embodiment, each process or function may be implemented by centralized processing by a single device or a single system, or by distributed processing by multiple devices or multiple systems.

[0069] Furthermore, in the above embodiment, each component may be configured with dedicated hardware, or, if it is a component that can be implemented by software, it may be implemented by executing a program. For example, each component can be implemented by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory. During execution, the program execution unit may execute the program while accessing the storage unit or recording medium. The program may also be executed by being downloaded from a server or the like, or by being executed by reading a program recorded on a predetermined recording medium (e.g., an optical disk, magnetic disk, semiconductor memory, etc.). Furthermore, this program may be used as a program that constitutes a program product. Furthermore, the computer executing the program may be one or multiple computers. That is, centralized processing may be performed, or distributed processing may be performed.

[0070] Furthermore, the embodiments described above are illustrative examples for specifically carrying out the present invention and do not limit the technical scope of the present invention. The technical scope of the present invention is indicated by the claims rather than by the description of the embodiments, and modifications within the literal scope and equivalent meaning of the claims are intended. [Explanation of Symbols]

[0071] 1 robot, 4 robot control unit, 11 servo amplifier, 12 memory unit, 13 circuit breaker, 14 power supply circuit, 15 measurement unit, 16 control unit

Claims

1. A servo amplifier that controls each motor in a robot having multiple arms connected by motor-driven joints, A storage unit in which the robot's operation program is stored, A control unit that operates the robot by controlling the servo amplifier based on the aforementioned operation program, A power supply circuit that supplies power to the servo amplifier and the control unit, It comprises a measuring unit for measuring the power supplied to the power supply circuit, The control unit, in test mode, operates the robot at multiple speeds of 100% or less based on the operation program, calculates the power consumption rate, which is the ratio of power consumption to rated power, using the power measured by the measuring unit according to the operation of the robot, and performs predetermined processing when the power consumption rate when the robot is operated at 100% speed exceeds a first threshold.

2. The predetermined process is a process that determines the ratio of the speed at which the robot is operated based on the operation program in order to ensure that the power consumption rate is below the first threshold, The robot control device according to claim 1, wherein the control unit operates the robot at the rate of the determined speed in the actual operating mode.

3. The robot control device according to claim 2, wherein the predetermined process is a process that determines the ratio of the speed of the operation program to the whole when operating the robot, in order to ensure that the power consumption rate is less than or equal to the first threshold.

4. The aforementioned operating program has multiple steps, The robot control device according to claim 2, wherein the predetermined process is a process that determines the ratio of speed for each of a plurality of steps in the operation program when operating the robot, in order to ensure that the power consumption rate is less than or equal to the first threshold.

5. The robot control device according to claim 1, wherein the predetermined processing includes a process of outputting power consumption rates for each of several percentages of speed, and a process of receiving an instruction to change the operation program in accordance with the output and changing the operation program in accordance with the instruction.

6. The robot control device according to any one of claims 1 to 5, wherein the control unit outputs an output indicating that the power measured by the measuring unit exceeds a second threshold when the robot is being operated in actual operating mode.

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