Robot control and management system

Abstract

Robot control (20) which causes a robot (10) to follow a target (O) while a transmission device moves the target (O), using a detection result obtained from a motion amount detection device (2b, 50) which detects an amount by which the transmission device (2) moves the target (O), wherein the robot control (20) comprises: a storage unit (23) which stores an upper limit and a lower limit for a velocity and / or an acceleration and / or a jerky movement of the target (O) which are calculated on the basis of a detection result obtained by the motion magnitude detection device (2b, 50), wherein the robot controller (20) performs a predetermined message, stops the robot (10) or moves the robot (10) to a stand-by position when the speed and / or acceleration and / or jerky motion calculated on the basis of the detection result obtained from the motion magnitude detection device (2b, 50) exceeds an upper limit or a lower limit immediately after the speed and / or acceleration and / or jerky motion exceeds the other upper limit or the other lower limit.

Description

[0001] The present invention relates to a robot controller and a management system.

[0002] In a known robot system in the prior art, a robot follows an object transferred from a transfer device in a state where the object is transferred from the transfer device, and thereby the robot picks up the object (see, for example, JP 2000-6069 A).

[0003] In a known transmission device, a theoretical value and an actual measured value of the drive for the transmission are compared, and a warning is issued based on the comparison result (see, for example, JP 2007-112565 A). PATENT LITERATURE JP 2000-6069 A JP 2007-112565 A DE 10 2018 114 682 A1 DE 10 2018 111 371 A1 DE 41 21 531 C2 EP 3 453 492 A1 EP 2 159 657 B1 US 2010 / 0017033 A1

[0004] DE 10 2018 114 682 A1 and DE 10 2018 111 371 A1 each disclose a robot system.

[0005] In addition, DE 41 21 531 C2 describes a motion control device for controlling the machining of a workpiece moved on a conveyor synchronously with the movement of the conveyor.

[0006] Furthermore, EP 3 453 492 A1 discloses a robot system and a robot controller. According to the embodiment of Fig. 1 shows a robot system 1 comprising a conveyor belt 10, a camera 11, a robot 20 and a robot controller 30.

[0007] Furthermore, EP 2 159 657 B1 discloses a method for controlling a robot performing movements, wherein a speed of a conveyor for moving a work object for the robot that deviates from a target speed is determined. In response to the determination that the conveyor speed has deviated, a new waiting position is created.

[0008] In addition, US 2010 / 0017033 describes, among other things, robot systems and user-operable robot control terminals.

[0009] In the robot system described above, the robot is made to follow the object based on the amount by which the transmission device moves the object. At this time, the amount of movement of the object is detected using a movement amount detection device that includes a pulley in contact with a belt of the transmission device and an encoder for detecting the amount of rotation of the pulley. If the movement amount detection device is not properly attached, if the movement amount detection device malfunctions, or if there is a problem in the communication of information between the movement amount detection device and the robot controller, the movement amount detection device outputs an abnormal detection result.Even in such a state, the robot continues the following operation based on the detection result obtained by the movement amount detection device, thus causing the robot to perform an unnatural movement. At this time, it is difficult to detect an abnormality in the movement amount detection device because the robot actually moving attracts more attention.

[0010] An object of the invention is to provide a robot control and management system that can reliably identify the cause of an anomaly at an early stage.

[0011] According to one aspect of the present disclosure, there is provided a robot controller that causes a robot to follow a target while a transmission device moves the target, using a detection result obtained by a movement amount detection device that detects an amount by which the transmission device moves the target, the robot controller comprising: a storage unit that stores an upper limit and a lower limit for at least one of a speed, an acceleration, and a jerky movement of the target, which are calculated based on a detection result obtained by the movement amount detection device, the robot controller performing a predetermined notification, stopping the robot, or moving the robot when at least one of the speed, the acceleration, and the jerky movement,which are calculated on the basis of the detection result obtained by the movement amount detection device, exceed an upper limit value or a lower limit value immediately after the speed and / or the acceleration and / or the jerky movement exceeds the other upper limit value or the other lower limit value. Fig. 1 schematically shows the design of a robot system according to an embodiment. Fig. 2 is a plan view of the relevant part of the robot system according to this embodiment. Fig. 3 is a block diagram of a robot controller of the robot system according to this embodiment. Fig. 4 is a flowchart showing the operation of a controller of the robot system according to this embodiment. Fig. 5 is a diagram for explaining a coordinate system for sequential control in the robot system according to this embodiment. Fig. 6 shows an exemplary time chart of speed based on a detection result obtained by a movement amount detecting device according to this embodiment. Fig. 7 schematically shows the configuration of a first modification of the robot system according to this embodiment. Fig. 8 schematically shows the configuration of a second modification of the robot system according to this embodiment.

[0012] A robot system 1 according to an embodiment will be described below using the drawings.

[0013] As in the Fig. 1 and Fig. 2, the robot system 1 according to this embodiment includes: a transmission device 2 that transmits an object (target) O serving as a work target; a robot 10 that performs predetermined work on the object O transmitted from the transmission device 2; a robot controller 20 that controls the robot 10; and a detection device 40.

[0014] The detection device 40 receives data that can identify the position and orientation of the object O transmitted from the transmission device 2. Any device that has such a function can be used as the detection device 40. Examples of the detection device 40 include a two-dimensional camera, a three-dimensional camera, a three-dimensional distance sensor, and a sensor that measures the shape of a target object by irradiating a line of light thereon. The detection device 40 in this embodiment is a two-dimensional camera attached to the upper part of the transmission device 2. The detection device 40 transmits detected image data to the robot controller 20. The image data is data that can identify at least the position of each object O.The image data may be data that can be used to identify the position and orientation of the object O.

[0015] Although the object O is not limited to a specific type, the object O in this embodiment is, for example, a workpiece. The transfer device 2 transfers the object O by driving a motor 2a in a predetermined direction. In this embodiment, the transfer device 2 transfers the object O toward the right side in Fig. 1.

[0016] The robot system 1 includes a movement amount detection device 50 that detects the amount by which the transmission device 2 moves the object O. The movement amount detection device 50 includes a roller 51 in contact with the transmission device 2 and a rotation sensor 52 that detects the amount of rotation of the roller 51 using a known device, such as an encoder. In this case, the amount of rotation of the roller 51 is linked to the amount of movement of the transmission device 2.

[0017] The motor 2a may include an operating position detection device (movement amount detection device) 2b, and the operating position detection device 2b may sequentially detect the rotational position and the rotation amount of the output shaft of the motor 2a. In such a case, the rotation amount of the output shaft of the motor 2a is linked to the movement amount of the transmission device 2. The operating position detection device 2b is, for example, an encoder. A detection value obtained by the movement amount detection device 50 or the operating position detection device 2b is transmitted to the robot controller 20.

[0018] The object O is a target on which the robot 10 performs predetermined work. In this embodiment, the robot 10 performs, as the predetermined work, picking up the object O, moving the object O to a predetermined location, assembling the object O to a predetermined part, or the like.

[0019] The robot 10 performs the above-described work on the object O in a state in which the object O is moved by the transmission device 2.

[0020] When the robot 10 performs predetermined work such as machining, welding, measuring, or deburring on an object that is a frame or the like, a work section in the frame serves as the target.

[0021] Although the robot 10 is not limited to one of a specific type, the robot 10 according to this embodiment includes a plurality of servo motors 11 each driving a plurality of moving parts (see Fig. 3). Each servo motor 11 has an operating position detection device for detecting its operating position. An example of an operating position detection device is an encoder. The detection value obtained by the operating position detection device is transmitted to the robot controller 20.

[0022] A hand 30 is attached to the distal end of the robot 10. Although the hand 30 supports the object O by gripping the object O with a plurality of claws in this embodiment, it is also possible to use a hand that supports the object O using magnetic force, air suction, or the like.

[0023] The hand 30 comprises a servo motor 31 for driving the claws (see Fig. 3). The servo motor 31 has an operating position detection device for detecting its operating position. An example of an operating position detection device is an encoder. The detection value obtained by the operating position detection device is transmitted to the robot controller 20.

[0024] Various types of servo motors, such as a rotary motor or a linear motor, can be used as the servo motors 11 and 31.

[0025] As in Fig. 3, the robot controller 20 includes: a control unit 21 including a CPU, a RAM, and the like; a display unit 22; a storage unit 23 including a non-volatile memory, a ROM, and the like; a plurality of servo controllers 24 corresponding to the respective servo motors 11 of the robot 10; a servo controller 25 corresponding to the servo motor 31 of the hand 30; an input unit 26 connected to the robot controller 20; and a transmitting / receiving unit 27. In one example, the input unit 26 is an input device, such as a control panel or the like, that can be worn by an operator. The input unit 26 also includes a display unit 26a. The input unit 26 may be a touchscreen input device. The input unit 26 may perform wireless communication with the robot controller 20.

[0026] The storage unit 23 stores a system program 23a, and the system program 23a executes basic functions of the robot controller 20. The storage unit 23 also stores an operation program 23b. The storage unit 23 also stores a follow-up program 23c and a motion amount anomaly response program 23d.

[0027] The control unit 21 sends control commands to the servo controllers 24 and 25 to perform predetermined work on the object O according to these programs. Consequently, the robot 10 and the hand 30 perform the predetermined work on the object O. Exemplary processing executed by the control unit 21 at this time will be described with reference to the flowchart in Fig. 4. Note that the control described below may be performed by other processing.

[0028] First, according to the follow-up program 23c, the control unit 21 obtains image data including an image of the object O from the detection device 40 (step S1-1). If the detection device 40 includes a processing unit for detecting the position and orientation of the object O from the image data, the control unit 21 can obtain the position and orientation of the object O from the detection device 40 in step S1-1.

[0029] The control unit 21 sets a following coordinate system that moves together with the object O on the transmission device 2 by using a detection value obtained by the movement amount detection device 50 when the detection device 40 captures the image data and a current detection value obtained by the movement amount detection device 50 (step S1-2).

[0030] Fig. 5 shows an exemplary tracking coordinate system. TF represents the tracking coordinate system at the time at which the detection device 40 acquires the image data of the object O. For example, the tracking coordinate system TF includes information about the position and orientation of the object. TF' represents the current tracking coordinate system. As shown in Fig. As shown in Figure 5, the current follower coordinate system TF' also contains information about the position and orientation of the object O. In other words, the object O has the same position and orientation information in both follower coordinate systems TF and TF'.

[0031] As shown in the following expression (1), the sequence coordinate system TF' is obtained using a coordinate transformation matrix T. TF′=T⋅TF

[0032] The motion component can be obtained using, for example, the following expression (2). (e2−e1) / S

[0033] In particular, the difference between the position of the object O detected in the following coordinate system TF and the current position of the object O is calculated sequentially.

[0034] Here, in expression (2), e1 is the detection value obtained by the movement amount detecting means 50 when the detecting means 40 captures the image data, and e2 is the current detection value obtained by the movement amount detecting means 50.

[0035] Here, S is the ratio of the count obtained by the movement amount detection means 50 to the amount by which the transmission means 2 moves the object O. More specifically, when S is 1, the detection result obtained by the movement amount detection means 50 is the amount by which the transmission means 2 moves the object O.

[0036] Next, the control unit 21 begins sending control commands to the robot 10 and the hand 30 according to the operation program 23b (step S1-3). Consequently, the hand 30 picks up a part 110 in a state where follow-up control is being executed, causing the hand 30 of the robot 10 to follow the object O.

[0037] To execute the following control, in step S1-3, the control unit 21 uses the following coordinate system TF' set in step S1-2 as a reference coordinate system of the robot 10 operating according to the operation program 23b. Thus, the reference coordinate system of the robot 10 moves in the transfer direction of the transfer device 2, and the movement of the reference coordinate system coincides with the movement of the object O moved by the transfer device 2. In this situation, the object O stops within the reference coordinate system even though the object O is moved by the transfer device 2 from the perspective of the control unit 21. Thus, the control unit 21 can cause the distal end of the robot 10 to stably follow the object O.

[0038] While this sequence control is being executed, the control unit 21 determines, according to the movement amount anomaly response program 23d, whether the speed calculated based on the detection result obtained by the movement amount detection means 50 is within a predetermined reference 23e (step S1-4). It is also possible to determine whether the acceleration or the jerking movement, instead of the speed, is within the reference 23e. The speed, acceleration, and jerking movement are calculated using the rotation amount, rotation speed, diameter, and the like of the roller 51 of the movement amount detection means 50.

[0039] The reference 23e is different from an upper limit limiter 23f of the speed, acceleration, jerking, or the like of the robot 10. In other words, the upper limit limiter 23f and the reference 23e are stored in the storage unit 23 of the robot controller 20. When the robot 10 operates at a speed, acceleration, jerking, or the like that exceeds the upper limit limiter 23f, the robot controller 20 issues a predetermined warning, stops the operation of the robot 10, or does something else. In step S1-4, the robot controller 20 performs the above-described determination based on the upper limit limiter 23f in addition to the above-described processing.

[0040] In one example, the speed calculated based on the detection result obtained by the movement amount detection device 50 fluctuates due to poor contact between the roller 51 of the movement amount detection device 50 and the transmission device 2. For example, when the roller 51 is intermittently in contact with the transmission device 2, the speed fluctuates, and the acceleration and jerky movement also fluctuate. Moreover, the detection result obtained by the movement amount detection device 50 is intermittently transmitted to the robot controller 20 due to poor contact inside the movement amount detection device 50, poor contact between the movement amount detection device 50 and the robot controller 20, and the like.In this case, too, the speed calculated based on the detection result obtained by the movement amount detection device 50, as well as the acceleration and jerking motion, fluctuate. In the following description, the speed, acceleration, and jerking motion calculated based on the detection result obtained by the movement amount detection device 50 may be simply referred to as the speed, acceleration, and jerking motion.

[0041] In one example, the reference 23e may be an upper limit of the speed, a lower limit of the speed, an upper limit of the acceleration, a lower limit of the acceleration, an upper limit of the jerky movement, or a lower limit of the jerky movement. In another example, the reference 23e may be a fluctuation pattern of the speed, acceleration, or jerky movement. For example, an upper limit of the fluctuation amount of the speed, acceleration, or jerky movement may be used as the pattern. For example, as in Fig. 6, the fluctuation of the speed suddenly increases from a time point and deviates from the upper limit value or the lower limit value of the speed or the upper limit value of the fluctuation amount of the speed serving as the reference 23e.

[0042] When it is determined that the value or pattern of the speed and / or acceleration and / or jerky movement calculated according to the movement amount abnormality response program 23d in step S1-4 deviates from the reference 23e, the control unit 21 executes a predetermined notification (step S1-5). Examples of the predetermined notification include making an indication that there is an abnormality in the detection result obtained by the movement amount detection means 50 using the display unit 22 or the display unit 26a, and outputting something to the effect that there is an abnormality using a predetermined voice output means.Other examples of the predetermined notification include making an indication, using the display unit 22 or the display unit 26a, of a time chart of the speed, the acceleration, or the jerky movement calculated based on the detection result obtained by the movement amount detecting means 50, as shown in FIG. Fig. 6. Text, the screen color, a predetermined representation, or the like can be used as the indication using the display unit 22 or the display unit 26a.

[0043] Other examples of the predetermined notification include providing an indication using the display unit 22 or the display unit 26a of scattered data showing the previous speed, acceleration, or jerky movement and the current speed, acceleration, or jerky movement. For example, a bar chart, a line chart, or the like showing the amounts of fluctuation in speed at a plurality of points in the past and the current amount of fluctuation in speed can be used as the scattered data.

[0044] Note that in step S1-5, the control unit 21 may cause the robot 10 to perform a danger avoidance operation together with or instead of the predetermined notification. The danger avoidance operation may include, for example, stopping the robot 10, moving the robot 10 to a standby position, reducing the operating speed of the robot 10, or the like.

[0045] Normally, the robot controller 20 continues the sequential control of the robot 10 according to the detection result obtained by the movement amount detection device 50 when the speed, acceleration, or jerky movement is within the upper limit limiter 23f. Thus, the robot controller 20 continues the sequential control even when the roller 51 of the movement amount detection device 50 and the transmission device 2 are intermittently in contact with each other. In this case, the robot 10 moves at a speed according to the detection result obtained by the movement amount detection device 50, which may appear as if the robot 10 is performing an abnormal operation.

[0046] In this embodiment, when the value or pattern of the speed and / or acceleration and / or jerky movement of the object O calculated based on the detection result obtained by the movement amount detection means 50 deviates from the predetermined reference 23e, the robot controller 20 displays a predetermined indication on the display unit 22 or the display unit 26a. In other words, when there is an abnormality in the detection result obtained by the movement amount detection means 50 while the follow-up control of the robot 10 continues, the predetermined indication appears on the display unit 22 or the display unit 26a. This configuration is advantageous for reliably identifying the cause of the abnormality at an early stage.More specifically, this configuration is advantageous for reliably detecting at an early stage that there is no anomaly in the robot 10.

[0047] The reference 23e can either be set by a user using the input unit 26 or automatically set by the robot controller 20. For example, the robot controller 20 calculates the upper speed limit and the lower speed limit based on the variance or the mean of the transmission speeds of the transmission device 2 at a normal time and automatically sets the upper speed limit and the lower speed limit as the reference 23e. In another example, the robot controller 20 automatically sets the upper speed limit, which is the value obtained by adding a predetermined value to the current transmission speed of the transmission device 2, and the lower speed limit, which is the value obtained by subtracting a predetermined value from the current transmission speed, as the reference 23e.In another example, the robot controller 20 calculates the allowable value of the speed, acceleration, or jerking motion from the previous fluctuation amount of the speed, acceleration, or jerking motion and sets this allowable value as the reference 23e. When the reference 23e is thus automatically set, the determination in step S1-4 and the predetermined notification in step S1-5 are more appropriately executed.

[0048] Furthermore, in this embodiment, the robot controller 20 can store detection result-related data, such as the detection result obtained by the movement amount detection device 50, the value of the speed, acceleration, or jerky movement, the amounts of fluctuation thereof, and their time charts, in the storage unit 23. The robot controller 20 can display, in response to the input to the input unit 26 or the like, an indication on the display unit 22 or the display unit 26a based on the collected detection result-related data. For example, a button for requesting a time chart, a button for requesting scattering data, a button for specifying the time range to be displayed, etc., are displayed on the input unit 26, and the time chart, scattering data, or the like are displayed based on the input to the input unit 26.Providing the collected information in response to the user's request as here is advantageous in finding an anomaly, identifying the cause of the anomaly, or the like.

[0049] The amount of movement of a mark on the transfer device 2, the object O, or the like can be detected based on image data obtained by an image pickup device that captures an image of the upper surface of the transfer device 2. Detection of the amount of movement based on the image data can be performed by the control unit 21 of the robot controller 20. In this case, the image pickup device and the control unit 21 serve as the movement amount detection means.

[0050] Instead of the transmission device 2, another robot or an automated guided vehicle (AGV) may move the object O. Also in this case, the same advantageous effect as before is obtained if it is possible to obtain the detection result showing the amount of movement of the object O based on a control command for the operation of the other robot or the amount of rotation of the wheels of the automated guided vehicle.

[0051] In the above embodiment, the robot controller 20 may have a learning function. For example, the storage unit 23 may store a learning program (learning unit) 23g, and the control unit 21 may learn according to the learning program 23g.

[0052] For example, the control unit 21 generates a table or expression that links the type of the transmission device 2, the transmission speed, the type of the movement amount detection device 50, the type of the object O, the number of objects O, etc., to the reference 23e using learning information, and stores the thus-generated table or expression in the storage unit 23. This generation of the table or expression is accomplished by learning to enable reliable detection of an abnormality at an early stage.

[0053] The data in which the amount of fluctuation in speed, acceleration, or jerky movement calculated based on the detection result obtained by the movement amount detection device 50 is associated with the type of the transmission device 2 can be used as the learning information. The data in which the type of object O or the number of objects O is associated with the amount of fluctuation in speed, acceleration, or jerky movement can also be used as the learning information. The data in which the type of the movement amount detection device 50 is associated with the amount of fluctuation in speed, acceleration, or jerky movement can also be used as the learning information.The data in which the amount of fluctuation in speed, acceleration, or jerky movement is linked to the result of a visual inspection of the operation of the robot 10 can also be used as the learning information. The result of a visual inspection can be the score obtained by evaluating the state of the robot 10 operating with different amounts of fluctuation in speed, acceleration, or jerky movement at multiple levels.

[0054] As a result of the robot controller 20 performing the learning in this way, the robot controller 20 can set a more suitable reference 23e.

[0055] As in Fig. As shown in Figure 7, the robot controller 20 may be connected to another robot controller 20. In this case, the table or expression obtained through learning, as described above, may be transmitted to the other robot controller 20 along with required information from a wireless or wired transmitting / receiving unit 27 of the robot controller 20. The required information includes the specifications of the robot 10 and the transmission device 2, the specifications of the movement amount detection device 50, the specifications of the hand 30, and the information of the object O relevant to generating the table or expression. The other robot controller 20 also transmits the learning result to the robot controller 20.

[0056] The robot controller 20 and the other robot controller 20 can use the received table or expression for sequence control. The robot controller 20 and the other robot controller 20 can use the received table or expression as the learning information.

[0057] As in Fig. As shown in Figure 8, a plurality of robot controllers 20 may be connected to a host control system 100. Examples of the host control system 100 include a production management system, a delivery management system, a robot management system, and a department management system. A plurality of host control systems may be connected to a central management system 200 or the like, which is another host control system. The plurality of robot controllers 20 and the host control system constitute the management system.

[0058] The host control system 100 and the central management system 200 each include: a control unit including a processor and the like; a display unit; a storage unit including a non-volatile memory, a ROM, a RAM, and the like; and an input device such as a keyboard, a touch panel, or a control panel.

[0059] The table or expression obtained through learning can be sent from the robot controller 20 to the host control system 100 or the central management system 200 along with the required information. The required information includes the specifications of the robot 10 and the transmission device 2, the specifications of the movement amount detection device 50, the specifications of the hand 30, and the information about the object O relevant to the generation of the table or expression.

[0060] The host control system 100 or the central management system 200 may perform learning using a plurality of tables or expressions relevant to the specifications of the same or the same type of robots 10, the same type of movement amount detection devices 50, and the same type of transmission devices 2 to form a new table or expression.

[0061] The host control system 100 or the central management system 200 sends the generated table or expression to the robot controller 20.

[0062] The robot controller 20 can use the received table or expression for sequential control. The other robot controller 20 can use the received table or expression as the learning information when that robot controller 20 executes the learning.

[0063] The robot controller 20, the host control system 100, or the central management system 200 can send the generated table or expression to a robot controller that does not have a learning function. This facilitates identifying the cause of an abnormality or performing other operations during the sequential control performed by the robot controller that does not have a learning function and its robot hand. LIST OF REFERENCE SYMBOLS 1 robot system 2 transmission device 2a Engine 2b Operating position detection device (movement amount detection device) 10 robots 11 Servo motor 20 Robot control 21 Control unit 22 Display unit 23 Storage unit 23a System program 23b Operating program 23c follow-up program 23d Movement Amount Anomaly Response Program 24 Servo control 25 Servo control 26 Input unit 27 Transceiver unit 30 hands 31 Servo motor 40 Detection device 50 Movement amount detection device 51 roll 52 tachometers O Object (target)

Claims

[1] A robot controller (20) that causes a robot (10) to follow a target (O) while a transmission device moves the target (O) using a detection result obtained by a movement amount detection device (2b, 50) that detects an amount by which the transmission device (2) moves the target (O), the robot controller (20) comprising: a storage unit (23) storing an upper limit value and a lower limit value for a speed and / or an acceleration and / or a jerky movement of the target (O), which are calculated on the basis of a detection result obtained by the movement amount detection means (2b, 50), wherein the robot controller (20) performs a predetermined notification, stopping the robot (10), or moving the robot (10) to a standby position when at least one of the speed, acceleration, and / or jerky movement calculated on the basis of the detection result obtained by the movement amount detection means (2b, 50) exceeds an upper limit value or a lower limit value immediately after the speed, acceleration, and / or jerky movement exceeds the other upper limit value or the other lower limit value. [2] The robot controller (20) according to claim 1, wherein the storage unit (23) stores the detection result-related data which is either the detection result obtained by the movement amount detecting means (2b, 50) or the speed, acceleration, and / or jerky movement, wherein the robot controller (20) is configured to display a time chart of the speed, acceleration, and / or jerky movement based on the detection result-related data stored in the storage unit (23). [3] Administrative system comprising: the robot controller (20) according to claim 1 or 2 and a host controller that receives from the robot controller (20) the detection result-related data, which is either the detection result obtained by the movement amount detection means (2b, 50), or the speed and / or the acceleration and / or the jerky movement, wherein the host controller determines the predetermined reference using at least the received detection result-related data.

Images