Tool and robot system

Abstract

This robot system (1) comprises: a conveyance device (2) that conveys a workpiece (W) to a prescribed work region; a robot (3) that executes work on the workpiece (W) disposed in a work region (X); a control device (4) that controls the robot (3); a position detection sensor (5) that detects the arrival of the workpiece (W) on the upstream side of the work region (X) in a conveyance direction; and a tool (10) provided with a tool base part fixed to the robot (3) and a wall part that is fixed to the tool base part and blocks the workpiece (W) by contacting a part, of the workpiece (W) being conveyed, on the downstream side in the conveyance direction. The tool (10) is provided independently of the conveyance device (2) and is disposed at a standby position in the work region (X) before the workpiece (W).

Description

Tool and Robot System

[0001] The present disclosure relates to a tool and a robot system.

[0002] A handling system is known that picks up one by one a plurality of objects conveyed by a conveyor by means of a manipulator unit disposed on the downstream side of the conveyor (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-252886

[0004] In the handling system as described above, in order to reliably pick up an object moving to the manipulator unit, an encoder for accurately detecting the moving speed of the conveyor must be mounted. However, not all conveyors necessarily have an encoder mounted thereon. Therefore, even when a workpiece is conveyed by a conveyor without an encoder, it is desired that a predetermined operation can be accurately performed on the workpiece.

[0005] One aspect of the present disclosure is a tool used in a conveying system for performing a predetermined operation on a workpiece conveyed by a conveying device, the tool including a tool base that is detachably fixed to an attachment target, and a wall portion that is fixed to the tool base and that blocks the workpiece by contacting a part on the downstream side in the conveying direction of the workpiece during conveyance.

[0006] Schematic diagram showing the configuration of a robot system according to an embodiment of the present disclosure. Perspective view showing the configuration of a tool according to an embodiment of the present disclosure. Flowchart for explaining the operation of the robot system shown in FIG. 1 Schematic diagram for explaining the operation of the robot system shown in FIG. 1 Schematic diagram for explaining the operation of the robot system shown in FIG. 1 Perspective view showing a modified example of the tool shown in FIG. 2

[0007] The configuration of a robot system 1 and a tool 10 according to one embodiment of this disclosure will be described below with reference to the drawings. The robot system 1 includes, for example, a conveyor (transporting device) 2 that transports a plurality of workpieces W in one direction, as shown in Figure 1, and a robot 3 that performs predetermined work on the workpieces W transported by the conveyor 2. The robot system 1 also includes a control device 4 that controls the conveyor 2 and the robot 3, and a camera (position detection sensor) 5 that photographs the workpieces W transported by the conveyor 2.

[0008] In this embodiment, the workpiece W is a roughly rectangular box-shaped object. The predetermined operation in this embodiment is the operation of attaching a label C, printed by a labeling device (not shown), to the upper surface of the workpiece W.

[0009] The conveyor 2 comprises, for example, a plurality of rollers arranged parallel to each other at equal intervals, and a pair of frame members 2d that support both sides of each roller, as shown in Figure 2.

[0010] The roller described above is composed of multiple drive rollers 2a and multiple driven rollers 2b, 2c. Specifically, the drive rollers 2a are arranged every two rollers, with one driven roller 2b, 2c placed between them. A belt (not shown) is stretched between each drive roller 2a and the adjacent pair of driven rollers 2b, 2c, so that the rotation of the drive roller 2a causes the pair of driven rollers 2b, 2c to rotate. Inside the frame member 2d, multiple motors (not shown) are arranged to rotate each drive roller 2a. In other words, these motors operate based on control commands from the control device 4, which will be described later, so that all rollers 2a, 2b, 2c rotate at the same speed and transport the workpiece W placed on each roller 2a to 2c in one direction.

[0011] Robot 3 is, for example, a 6-axis articulated robot positioned near conveyor 2. Furthermore, a flange 3a is provided at the tip of robot 3 to which a robot hand or a specialized tool corresponding to various tasks performed by robot 3 can be attached. In this embodiment, the flange 3a is fitted with the tool 10 according to this embodiment, which is a specialized tool for attaching a label C to the upper surface of the workpiece W.

[0012] Tool 10, for example as shown in Figure 2, comprises a frame 20, a plurality of suction pads 30 for adsorbing labels C printed by a labeling device (not shown), and a laser sensor (sensor) 40.

[0013] The frame 20 is formed in a shape that is substantially L-shaped in side view by multiple metal members made of metal such as aluminum alloy. The frame 20 includes a tool base 22 having a mounting portion 21 that can be detachably attached to the flange 3a, and a wall portion 23 that extends from one end of the tool base 22 in a direction perpendicular to the tool base 22. In this case, the tool base 22 is made up of a substantially rectangular plate 22a to which the mounting portion 21 is attached, and a plate 22b of about the same size as plate 22a, which are arranged parallel to each other with a gap in the thickness direction. In the following, the case in which the tool 10 is in the basic position, that is, the position in which the tool base 22 extends horizontally and the wall portion 23 extends vertically downward as shown in Figure 2, will be described as an example.

[0014] Each suction pad 30 is fixed to the plate 22b with a gap between them. In the example shown in Figure 2, four suction pads 30 are provided, and each suction pad 30 is positioned to correspond to the four corners of the label C. Furthermore, the suction surface of each suction pad 30 is positioned along the surface of the plate 22b that is offset downwards from the lower surface. That is, as shown in Figure 2, the suction pads 30 can hold the label C in a horizontal position between the tool base 22 and the wall 23.

[0015] The laser sensor 40 is a sensor that detects the distance to an object irradiated by a laser 41, for example, by irradiating it with a laser 41 and based on the time it takes for the laser 41 to reflect. In Figure 2, the laser sensor 40 is attached to the corner between the plate 22a and the wall portion 23, and the laser 41 is irradiated downward along the inner surface of the wall portion 23. In other words, the laser sensor 40 can be used to detect whether or not a workpiece W is present at a position in contact with the inner surface of the wall portion 23. The information regarding the presence or absence of the detected workpiece W is transmitted to the control device 4.

[0016] The control device 4 includes at least one memory (not shown), such as ROM and RAM, and at least one processor (not shown), such as a CPU. In this embodiment, the control device 4 combines a control device for controlling the conveyor 2 and a control device for controlling the robot 3 and tool 10 into a single control device. In other words, the memory of the control device 4 stores a transport program for driving the conveyor 2 and an operation program for operating the robot 3 and tool 10 to perform predetermined tasks. The memory of the control device 4 also stores the field of view of the camera 5, i.e., the shooting area Y, and the distance L between the work area X where the robot 3, set on the conveyor 2, performs predetermined tasks.

[0017] The processor of the control device 4 executes a transport program stored in memory, outputting control signals to the conveyor 2 to operate multiple motors that rotate each drive roller 2a. As a result, each roller 2a to 2c of the conveyor 2 rotates at a constant speed, and the conveyor 2 becomes ready to transport the workpiece W. The processor of the control device 4 also sends a shooting command to the camera 5, causing the camera 5 to take pictures at a predetermined sampling period. Furthermore, the processor of the control device 4 executes an operation program stored in memory, operating the robot 3 to move the tool 10 to the work area X, and then causing the workpiece W entering the work area X to perform a predetermined operation.

[0018] Camera 5 is a two-dimensional camera positioned above the conveyor 2, upstream of the work area X, as shown in Figure 1. In this case, the height of camera 5 is such that the entire upper surface of the workpiece W and the entire width of the conveyor 2 are contained within the shooting area Y, and the camera 5 then photographs the target object, including the workpiece W, within the shooting area Y, in accordance with the shooting command sent from the control device 4, and transmits the captured image to the control device 4.

[0019] The operation of the robot system 1 and tool 10 configured in this embodiment will be described below. In the following description, we will explain using the flowchart shown in Figure 3 as an example, in which the robot 3 is made to affix one label C at a time to the upper surface of multiple workpieces W that are sequentially transported by the conveyor 2 shown in Figure 1.

[0020] First, the workpiece W to be worked on is transported from the upstream of the conveyor 2 and enters the shooting area Y. At this point, the entire workpiece W is photographed from above by the camera 5. The two-dimensional image (photographed image) acquired by the camera 5 and the time of the photograph are then transmitted to the control device 4. As a result, the control device 4 acquires the arrival time of the workpiece W to be worked on when it entered the shooting area Y, and the photographed image of the workpiece W (step S1).

[0021] Next, the control device 4 calculates the estimated time when the workpiece W will reach the work area X based on the arrival time received from the camera 5, the conveying speed of the conveyor 2, and the distance L (step S2). In this case, the conveying speed can be calculated based on the motor rotation speed command information included in the conveying program stored in the memory of the control device 4, i.e., the operation command for the conveyor 2. In other words, the control device 4 can determine the theoretical value of the conveying speed of the conveyor 2 from the operation command it sends to the conveyor 2.

[0022] Furthermore, the control device 4 extracts the workpiece W from the captured image by processing the image of the workpiece W received from the camera 5. As a result, the control device 4 detects the shape of the top surface of the workpiece W, in particular the angle (orientation) of the surface located furthest downstream (hereinafter also referred to as the leading surface) with respect to the transport direction, and its position in the width direction of the conveyor 2 (step S3).

[0023] Subsequently, the control device 4 operates the robot 3 to direct the tool 10 toward the labeling device, causing the label C printed by the labeling device to adhere to the suction pad 30. Then, as shown in Figure 4, the control device 4 moves the tool 10, holding the label C, into the work area X before the calculated time when the workpiece W is scheduled to arrive in the work area X. The control device 4 also positions the wall portion 23 of the tool 10 at a position (standby position) corresponding to the orientation of the leading surface of the detected workpiece W and its position in the width direction of the conveyor 2. In other words, the control device 4 keeps the tool 10 in standby position so that when the workpiece W arrives in the work area X, the leading surface of the workpiece W will be in surface contact with the wall portion 23 (step S4).

[0024] As a result, as shown in Figure 5, the leading surface of the workpiece W can be brought into contact with the wall portion 23 of the tool 10, which is waiting in the work area X, thereby blocking the workpiece W (step S5). At this time, the laser sensor 40 detects that the leading surface of the workpiece W has come into contact with the wall portion 23 and transmits this information to the control device 4. The control device 4 then operates the robot 3 in accordance with the timing of receiving the information from the laser sensor 40, causing it to attach the label C to the upper surface of the workpiece W (step S6). That is, the robot 3 moves the tool 10 only in the direction in which the wall portion 23 extends, i.e., downward, thereby maintaining the blocked state of the workpiece W and pressing the label C held by the suction pad 30 against the upper surface of the workpiece W.

[0025] Subsequently, the control device 4 operates the robot 3 and moves the tool 10 upwards, thereby separating the front surface of the workpiece W from the wall 23. This releases the workpiece W from being blocked, and the workpiece W with the label C attached is transported downstream (step S7). By repeating this series of controls, one label C can be attached to the top surface of each of the multiple workpieces W being sequentially transported by the conveyor 2.

[0026] As described above, the robot system 1 and tool 10 according to this embodiment allow the tool 10 to be kept in standby mode based on the position and orientation of the workpiece W acquired by the upstream camera 5. This ensures that the tool 10 can reliably make contact with the workpiece W within the work area X, even if the timing of the workpiece W entering the work area X cannot be accurately determined. By blocking the workpiece W with the tool 10, a predetermined operation can be performed on the workpiece W with high precision. In other words, even if the conveyor 2 transporting the workpiece W is not equipped with an encoder, or if the friction between the conveyor 2 and the workpiece W is small and slippage occurs, the predetermined operation can be reliably performed.

[0027] Furthermore, in this embodiment, the orientation and position of the tool 10 can be adjusted according to the orientation of the leading surface of the workpiece W being transported and its position in the width direction of the conveyor 2. Therefore, even if the orientations of multiple workpieces W being transported sequentially are not uniform, each workpiece W can be reliably stopped. This allows each workpiece W to be stopped more stably when applying the label C, thereby improving the accuracy of the label application work.

[0028] Furthermore, according to this embodiment, the size of the front surface of the workpiece W can be detected based on the image captured by the camera 5. Therefore, the wall portion 23 can be brought into contact with the center position in the width direction of the front surface of each workpiece W. This also has the advantage of making the position where the label C is attached more stable.

[0029] Furthermore, in this embodiment, the laser sensor 40 attached to the tool 10 can accurately detect the timing when the workpiece W comes into contact with the wall portion 23. That is, the label application work can be performed in accordance with the timing when the workpiece W comes into contact with the wall portion 23. This minimizes the time the workpiece W is held in place and improves the work efficiency of the label application work.

[0030] In this embodiment, the tool 10 may be provided with a guide function that guides the workpiece W toward the inner surface of the wall portion 23. For example, as shown in Figure 6, the tool 10 may be provided with a pair of guide portions 24 that extend diagonally forward and outward on both sides of the lower end of the wall portion 23.

[0031] In this case, the transported workpiece W contacts one of the pair of guides 24 before contacting the wall 23, and is moved along the guide 24 toward the inner surface of the wall 23. Therefore, the label C can be applied accurately without having to precisely match the position and orientation of the leading surface of the transported workpiece W to the position and orientation of the tool 10 waiting in the work area X.

[0032] In other words, if the opening width of the guide section 24 is approximately the same as the width dimension of the conveyor 2, the detection of the orientation and position of the workpiece W by the camera 5 can be omitted. Therefore, in such cases, instead of the camera 5, a photoelectric sensor or the like may be used to detect the arrival of the workpiece W by irradiating a laser along the width direction of the conveyor 2 and detecting the interruption of the laser. This makes it possible to reduce the cost required for the robot system by replacing the camera 5 with a sensor at a lower cost.

[0033] Furthermore, in this embodiment, the tool 10 was equipped with a laser sensor 40 that detects contact between the workpiece W and the wall portion 23, but the laser sensor 40 may be replaced with another sensor.

[0034] For example, if the workpiece W is relatively heavy and the impact when the workpiece W hits the wall 23 is transmitted to the wrist side of the robot 3, the force sensor provided on the wrist of the robot 3 may be used instead of the laser sensor 40. In this case, the laser sensor 40 is omitted and the force sensor originally attached to the robot 3 is used, thus reducing the cost of the robot system 1 by the amount of the laser sensor 40.

[0035] Furthermore, in this embodiment, the conveyor 2 was kept running without stopping when the workpiece W was blocked by the tool 10 and the label C was applied. Alternatively, the control device 4 may stop the operation of the conveyor 2 at the same time that the workpiece W hits the wall portion 23 of the tool 10. In other words, the conveyor 2 may be controlled to operate intermittently. In this case, the workpiece W can be made more stable when the label C is applied, and the accuracy of the work can be improved.

[0036] Furthermore, if the conveyor 2 operates intermittently, the robot 3 may perform predetermined tasks on multiple workpieces W at once. For example, if the robot 3 is to attach labels C to two workpieces W at once, the camera 5 will capture images of both workpieces W in a single image. The control device 4 will then detect the position and orientation of the leading surfaces of both workpieces W from the captured image.

[0037] As a result, the control device 4 first positions the tool 10 (wall portion 23) at a location corresponding to the leading surface of the workpiece W that is further forward of the two workpieces W. Then, as soon as the leading workpiece W is blocked by the tool 10, the conveyor 2 is stopped and the label C is attached to the leading workpiece W. After that, the tool 10 is directed towards the position of the leading surface of the other workpiece W that has been detected, and once the label C is attached to the other workpiece W as well, the tool 10 is retracted and the conveyor 2 resumes transport. In this way, even when performing a predetermined operation on two workpieces W at once, the same control as described above can be performed.

[0038] Furthermore, in this embodiment, the camera 5 and the control device 4 detect the orientation (shape) of the workpiece W and its position in the width direction of the conveyor 2. Alternatively, for example, the camera 5 could be made a three-dimensional camera to detect the height dimension of the workpiece W. In this case, the range in which the workpiece W exists within the work area X can be grasped more accurately, and the workpiece W can be stopped more reliably.

[0039] In this embodiment, the tool 10 is attached to the robot 3, and both are controlled by the control device 4. Alternatively, the tool 10 may be attached to a mechanism independent of the conveyor 2 and the robot 3. In other words, the mechanism to which the tool 10 is attached in this case is, for example, a dedicated device for detecting the position and orientation of the front surface of the workpiece W based on images acquired from the camera 5, and for moving the tool 10 to the corresponding position and orientation. Then, by connecting this dedicated device with the control devices that control the conveyor 2, the robot 3, and the tool 10 via wired or wireless means, and enabling the transmission and reception of information, the same control as described above can be performed.

[0040] Furthermore, in this embodiment, the leading surface of the workpiece W is abutted against the wall portion 23 of the tool 10, but the portion that abuts against the wall portion 23 can be arbitrarily changed according to the shape of the workpiece W.

[0041] Furthermore, in this embodiment, tool 10 is a dedicated tool for attaching label C to the upper surface of workpiece W, but tool 10 may be other tools such as a robot hand. Also, in this embodiment, conveyor 2 is exemplified as a roller conveyor that transports workpiece W by the rotation of multiple rollers, but conveyor 2 may be other types of transport devices such as a belt conveyor.

[0042] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of the invention or from the spirit and intent of the invention derived from the claims and their equivalents. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto.

[0043] The following further notes are disclosed regarding the above embodiments and modifications: (Note 1) A tool for use in a transport system that performs a predetermined operation on a workpiece transported by a transport device, comprising a tool base that is detachably fixed to an object to be attached, and a wall that is fixed to the tool base and blocks the workpiece by contacting a part of the downstream side of the workpiece in the transport direction during transport. (Note 2) The tool according to Note 1, further comprising a sensor that detects when the workpiece has come into contact with the wall. (Note 3) The tool according to Note 1 or Note 2, further comprising a guide that adjusts the posture of the workpiece by utilizing the force acting on the workpiece from the transport device before the workpiece comes into contact with the wall. (Note 4) A robot system comprising: a transport device for transporting the workpiece to a predetermined work area; a robot for performing work on the workpiece placed in the work area; a control device for controlling the robot; a position detection sensor for detecting the arrival of the workpiece upstream of the work area in the transport direction; and a tool as described in any of Notes 1 to 3, wherein the tool is provided independently of the transport device and is positioned in a waiting position within the work area before the workpiece. (Note 5) The robot system as described in Note 4, wherein the mounting target is the robot. (Note 6) The robot system as described in Note 4 or Note 5, wherein the position detection sensor detects the orientation of the workpiece, and the wall portion of the tool in the waiting position is positioned facing the direction corresponding to the orientation of the workpiece. (Note 7) The robot system as described in any of Notes 4 to 6, wherein the position detection sensor detects the position of the workpiece in the width direction of the transport device, and the wall portion of the tool in the waiting position is positioned in the waiting position corresponding to the position. (Note 8) The robot system according to any one of Notes 4 to 7, wherein the position detection sensor detects the height dimension of the workpiece, and the wall portion of the tool in the standby position is positioned at a height corresponding to the height dimension.

[0044] 1 Robot system 3 Robot 4 Control device 5 Camera (position detection sensor) 10 Tool 22 Tool base 23 Wall section 24 Guide section 40 Laser sensor (sensor) W Work

Claims

1. A tool for use in a conveying system that performs a predetermined operation on a workpiece conveyed by a conveying device, comprising: a tool base that is detachably fixed to the object to be attached; and a wall that is fixed to the tool base and blocks the workpiece by contacting a part of the downstream side of the workpiece in the conveying direction during conveyance.

2. The tool according to claim 1, further comprising a sensor for detecting when the workpiece comes into contact with the wall.

3. The tool according to claim 1 or 2, further comprising a guide section that adjusts the orientation of the workpiece by utilizing the force acting on the workpiece from the conveying device before the workpiece comes into contact with the wall.

4. A robot system comprising: a transport device for transporting the workpiece to a predetermined work area; a robot for performing work on the workpiece placed within the work area; a control device for controlling the robot; a position detection sensor for detecting the arrival of the workpiece upstream of the work area in the transport direction; and a tool according to any one of claims 1 to 3, wherein the tool is provided independently of the transport device and is positioned in a waiting position within the work area before the workpiece.

5. The robot system according to claim 4, wherein the mounting target is the robot.

6. The robot system according to claim 4 or 5, wherein the position detection sensor detects the orientation of the workpiece, and the wall portion of the tool in the standby position is positioned facing a direction corresponding to the orientation of the workpiece.

7. The robot system according to any one of claims 4 to 6, wherein the position detection sensor detects the position of the workpiece in the width direction of the transport device, and the wall portion of the tool in the standby position is positioned in the standby position corresponding to the position.

8. The robot system according to any one of claims 4 to 7, wherein the position detection sensor detects the height dimension of the workpiece, and the wall portion of the tool in the standby position is positioned at a height corresponding to the height dimension.

Images