Assistance device for assisting robot hand in holding workpiece, robot system, and method for holding workpiece in robot system

Abstract

An assistance device (5) comprises: an inclined part (51, 52) which supports a bottom part of a workpiece (9) and which inclines the workpiece in the vertical direction, thereby bringing a side part of the workpiece into contact with a suction part (26) of a robot hand (2) using the weight of the workpiece; and a slit (53) which positions a support part (22) of the robot hand below the workpiece that is supported by the inclined part and which allows the support part to move upward such that the workpiece can be reloaded onto the support part from the inclined part.

Description

Auxiliary device for assisting robot hand in holding a workpiece, robot system, and method for holding a workpiece in a robot system

[0001] The technology disclosed herein relates to an assisting device that assists a robot hand in holding a workpiece, a robot system, and a method for holding a workpiece in a robot system.

[0002] Patent Document 1 describes a conventional holding device. The holding device is moved by a drive device. The holding device transports a workpiece. The holding device has a support part and an adsorption part. The support part supports the weight of the workpiece in the vertical direction. The workpiece is a cardboard box in which items are packed. The support part also moves in the front-to-rear direction. The adsorption part is located above the support part and adsorbs the side of the workpiece. With the adsorption part adsorbing the side of the workpiece, the holding device moves the support part forward, positioning the support part below the workpiece. With the support part positioned below the workpiece, the driving device raises the holding device. The support part supports the bottom surface of the workpiece and the adsorption part adsorbs the side of the workpiece, thereby holding the workpiece.

[0003] Patent No. 7448372

[0004] When holding a workpiece, the conventional holding device sandwiches the workpiece between a stopper adjacent to the roller conveyor and the suction part, and presses the suction part against the workpiece. The action of pressing the suction part against the workpiece reduces the efficiency of the workpiece transport operation. However, because the suction part is oriented horizontally, the suction part cannot stably adsorb the workpiece unless it is pressed against the side of the workpiece.

[0005] The technology disclosed herein relates to an auxiliary device that assists a robot hand in holding a workpiece. The auxiliary device includes an inclined portion that supports the bottom of the workpiece and tilts the workpiece vertically so that the side of the workpiece abuts against a suction portion of the robot hand due to the workpiece's own weight, and a slit that positions a support portion of the robot hand below the workpiece supported on the inclined portion and allows the support portion to move upward so that the workpiece can be transferred from the inclined portion to the support portion.

[0006] The tilting section of the auxiliary device tilts the workpiece, causing the workpiece's own weight to abut the side of the workpiece against the suction section of the robot hand, allowing the suction section to stably pick up the side of the workpiece, allowing the robot hand to quickly and stably hold the workpiece.

[0007] FIG. 1 shows a robot system. FIG. 2 shows a robot hand. FIG. 3 shows a clamping portion and a second suction portion. FIG. 4 shows a manner in which a workpiece is held by the robot hand. FIG. 5 shows an auxiliary device. FIG. 6 shows a state in which a workpiece is supported by the auxiliary device. FIG. 7 shows the operation of the positioning mechanism of the auxiliary device. FIG. 8 shows a portion of the operation in which the robot hand holds a workpiece from the auxiliary device. FIG. 9 shows a portion of the operation in which the robot hand holds a workpiece from the auxiliary device. FIG. 10 illustrates an example of a workpiece held by the robot hand. FIG. 11 shows an auxiliary device according to a modified example.

[0008] Hereinafter, embodiments of an auxiliary device that assists a robot hand in holding a workpiece, a robot system, and a method for holding a workpiece in a robot system will be described with reference to the drawings. The auxiliary device, robot system, and method for holding a workpiece in a robot system described here are examples.

[0009] (Robot System) Fig. 1 shows a robot system 1 equipped with a robot hand. The robot system 1 is constructed in, for example, a logistics center. The logistics center is a collection and delivery base where incoming products are sorted. However, the application of the robot system 1 is not limited to logistics centers.

[0010] The robot system 1 includes a robot 11. The robot 11 transports a product, which is a workpiece 9. More specifically, the robot 11 lifts the workpiece 9 from a conveyor 14 and loads it onto a cart 16. The robot 11 is, for example, an articulated robot. The illustrated robot 11 is a six-axis vertical articulated robot. Note that the number of axes of the manipulator is not limited to a specific number. The robot 11 has a base 12. The base 12 is fixed to, for example, the floor. The robot 11 has an arm 13. A first end of the arm 13 is supported by the base 12. A robot hand 2 serving as an end effector is connected to a second end of the arm 13. Note that the robot 11 may be mounted on a vehicle to move within a logistics center. The vehicle may be, for example, an automated guided vehicle (AGV) or an autonomous mobile robot (AMR).

[0011] The robot system 1 includes a robot controller 15. The robot controller 15 is electrically connected to the robot 11. The robot controller 15 controls the operation of the robot 11.

[0012] The robot controller 15 is communicatively connected to a WMS (Warehouse Management System) 17. The WMS 17 provides the robot system 1 with information about the workpieces 9 being sequentially transported by the conveyor 14. The information about the workpieces 9 includes at least information about the shape of the workpieces 9, information about the destination of the workpieces 9, and the type of workpiece 9 (e.g., information about the products in a cardboard box). Based on the information from the WMS 17, the robot controller 15 controls the robot hand 2 in accordance with the shape of the workpiece 9 to be lifted next. The robot controller 15 also controls the robot 11 so that the workpieces 9 are loaded onto a specified cart 16.

[0013] The conveyor 14 is, for example, a roller conveyor. A roller conveyor has a number of rollers lined up. The workpiece 9 is transported by the rotation of the number of rollers. The robot 11 lifts the workpiece 9 from the end of the conveyor 14. Note that in the robot system 1, the means for transporting the workpiece 9 to the vicinity of the robot 11 is not limited to the conveyor 14.

[0014] The robot system 1 includes an auxiliary device 5. The auxiliary device 5 is located at the end of the conveyor 14. The auxiliary device 5 assists the robot hand 2 in holding the workpiece 9. The structure of the auxiliary device 5 will be described later.

[0015] 1, the workpiece 9 is depicted as a square box, but the shape of the workpiece 9 is not limited to a box. For example, as shown in FIG. 10, the workpiece 9 may be a product in which a plurality of bottles 91 are shrink-wrapped. The top surface or side surface of the workpiece 9 is not necessarily flat.

[0016] 2 shows the robot hand 2. The robot hand 2 holds a workpiece 9. The robot hand 2 has a connection portion 21. The connection portion 21 is connected to the second end of the arm 13 of the robot 11.

[0017] In the following description, the directions of the robot hand 2 are defined as follows: The front-to-rear direction of the robot hand 2 corresponds to the direction in which the robot hand 2 approaches or moves away from the workpiece 9. The left-to-right direction of the robot hand 2 is a horizontal direction perpendicular to the front-to-rear direction. The left-to-right direction of the robot hand 2 can also be referred to as the width direction. The up-to-down direction of the robot hand 2 is a direction perpendicular to the front-to-rear direction and the left-to-right direction. Note that these front-to-rear direction, left-to-right direction, and up-to-down direction are used only in the description of the robot hand 2 or the auxiliary device 5 described below, and are not used to limit the structure or shape of the robot hand 2 or the structure or shape of the auxiliary device 5.

[0018] The robot hand 2 has a support portion 22. The support portion 22 supports the workpiece 9 from below. The support portion 22 of the robot hand 2 shown in FIG. 2 has a first placement portion 221, a second placement portion 222, a third placement portion 223, and a fourth placement portion 224. The first placement portion 221, the second placement portion 222, the third placement portion 223, and the fourth placement portion 224 each extend in the front-to-rear direction. The workpiece 9 is placed on the upper surface of the first placement portion 221, the second placement portion 222, the third placement portion 223, and the fourth placement portion 224. The support portion 22 has a placement surface for the workpiece 9. The first placement portion 221, the second placement portion 222, the third placement portion 223, and the fourth placement portion 224 are arranged at intervals in the left-to-right direction. The support portion 22 has a fork shape extending from the rear to the front. The number of mounting portions that the support portion 22 has is not limited to a specific number.

[0019] Here, the support portion 22 has a relatively narrow width. The width of the support portion 22 is, for example, 100 mm to 250 mm. However, the width of the support portion 22 of the robot hand 2 disclosed herein is not limited to the above numerical range. The width of the support portion 22 of the robot hand 2 may be wider than the above numerical range. Note that the width of the workpiece 9 that can be held by the robot hand 2 is not limited to a specific width. The robot hand 2 can hold a workpiece 9 having a width of, for example, 100 mm to 500 mm.

[0020] The support unit 22 is supported by the main body 20 of the robot hand 2 so as to be movable in the front-rear direction (see the solid arrow in the upper diagram of FIG. 2 ). More specifically, the support unit 22 moves in the front-rear direction between a support position and a retracted position. As shown in the upper diagram of FIG. 2 , the support position is a position where the first mounting unit 221, the second mounting unit 222, the third mounting unit 223, and the fourth mounting unit 224 are located below the clamping unit 23, which will be described later. As shown in the lower diagram of FIG. 2 , the retracted position is a position where the first mounting unit 221, the second mounting unit 222, the third mounting unit 223, and the fourth mounting unit 224 are separated from below the clamping unit 23. The robot hand 2 has a movement mechanism that moves the support unit 22. The movement mechanism includes, for example, an electric motor 225 as a drive source and a mechanism that converts the driving force of the electric motor into front-rear movement of the support unit 22. The robot controller 15 adjusts the position of the support part 22 in the front-rear direction by outputting a control signal to the electric motor 225 .

[0021] The robot hand 2 has a first suction portion 26. The first suction portion 26 sucks the side surface of the workpiece 9 (see FIG. 4 ). The first suction portion 26 is located near the lower end of a second actuator 25 (described later). The first suction portion 26 is located between the first to fourth placement portions 221, 222, 223, and 224 of the support portion 22 and the clamping portion 23 in the up-down direction. The first suction portion 26 is also located near the front ends of the first to fourth placement portions 221, 222, 223, and 224 of the support portion 22 when the support portion 22 is in the retracted position, as shown in the lower view of FIG. 2 . The position of the first suction portion 26 in the up-down direction is also near the rear ends of the first to fourth placement portions 221, 222, 223, and 224 of the support portion 22 when the support portion 22 is in the support position, as shown in the upper view of FIG. 2 .

[0022] The first suction unit 26 has a plurality of suction cups 261. The plurality of suction cups 261 are arranged in the vertical and horizontal directions. The number of suction cups 261 is not limited to a specific number.

[0023] The suction cup 261 is a bellows-shaped cup with an opening. The opening of the suction cup 261 faces forward. The first suction portion 26 faces horizontally. The opening abuts the side of the workpiece 9. The suction cup 261 has a suction hole at its bottom. As shown in the upper diagram of FIG. 2 , the suction hole is connected to the negative pressure supply device 31 via a tube. When the opening of the suction cup 261 abuts the side of the workpiece 9, negative pressure is supplied to the suction cup 261, allowing the first suction portion 26 to adsorb the side of the workpiece 9. Because the bellows-shaped suction cup 261 is elastically deformable, the workpiece 9 is allowed to slightly displace while the first suction portion 26 maintains its state of adsorbing the side of the workpiece 9.

[0024] The negative pressure supply device 31 may be a known device having, for example, a compressor and an ejector, or may be a device using a vacuum pump.

[0025] The robot hand 2 has a clamping portion 23. The clamping portion 23 clamps the workpiece 9 between itself and the support portion 22 in the vertical direction. Fig. 3 shows the clamping portion 23. The left diagram of Fig. 3 is a bottom view of the clamping portion 23, and the right diagram is a cross-sectional view taken along line A-A of the left diagram.

[0026] The clamping portion 23 has a flat plate shape that extends horizontally. The clamping portion 23 has a second suction portion 231. The second suction portion 231 is attached to the lower surface of the clamping portion 23. The second suction portion 231 has a contact surface 232 that contacts the upper part of the workpiece 9. The second suction portion 231 is made of a synthetic resin or rubber sponge. The contact surface 232 is flexible. When the clamping portion 23 contacts the upper part of the workpiece 9, the contact surface 232 deforms to follow the shape of the upper part, thereby adhering closely to the upper part. Note that the second suction portion 231 is not limited to a sponge, as long as it is elastically deformable and the contact surface 232 has flexibility to follow the shape of the upper part of the workpiece 9.

[0027] The second suction portion 231 has a plurality of suction holes 233. The suction holes 233 open to the abutment surface 232. The suction holes 233 penetrate the second suction portion 231 in the vertical direction (i.e., in the thickness direction of the second suction portion 231) and communicate with the hollow portion 230 of the clamping portion 23. As shown in the upper diagram of FIG. 2 , the hollow portion 230 is connected to the negative pressure supply device 31 via a tube. When negative pressure is supplied from the negative pressure supply device 31 to the second suction portion 231 with the abutment surface 232 abutting against the top of the workpiece 9, the second suction portion 231 can adsorb the workpiece 9.

[0028] The robot controller 15 switches between supplying and stopping the supply of negative pressure from the negative pressure supply device 31 to the first suction unit 26, and switches between supplying and stopping the supply of negative pressure from the negative pressure supply device 31 to the second suction unit 231. The robot controller 15 controls a valve 310. The valve 310 is interposed between the negative pressure supply device 31 and the first suction unit 26 or the second suction unit 231. The valve 310 switches between supplying and stopping the supply of negative pressure to the first suction unit 26, and switches between supplying and stopping the supply of negative pressure to the second suction unit 231. The robot hand 2 switches between (1) a state in which negative pressure is supplied to the first suction unit 26, (2) a state in which negative pressure is supplied to the second suction unit 231, and (3) a state in which negative pressure is supplied to both the first suction unit 26 and the second suction unit 231.

[0029] In addition, instead of one negative pressure supply device 31 supplying negative pressure to each of the first suction portion 26 and the second suction portion 231, the robot system 1 may be equipped with a negative pressure supply device that supplies negative pressure to the first suction portion 26 and a negative pressure supply device that supplies negative pressure to the second suction portion 231.

[0030] The robot hand 2 has a first actuator 24. The first actuator 24 moves the clamping portion 23 downward or upward. The first actuator 24 includes an air cylinder. The air cylinder is arranged so that its axis faces the vertical direction. A rod 241 of the air cylinder is connected to the clamping portion 23. As shown in the lower diagram of FIG. 2 , when compressed air is supplied or discharged from the air supply device 32, the rod 241 of the first actuator 24 extends downward to displace the clamping portion 23 downward, and also contracts upward to displace the clamping portion 23 upward.

[0031] The air supply device 32 includes, for example, a compressor. The compressor of the air supply device 32 and the compressor of the negative pressure supply device 31 may be the same. The robot controller 15 outputs an open / close signal to a valve 242 between the air supply device 32 and the first actuator 24. By controlling the valve 242, the holding portion 23 is displaced in the vertical direction.

[0032] The robot hand 2 has a second actuator 25. The second actuator 25 reciprocates the first actuator 24 in the vertical direction (see the dotted arrow in the upper diagram of Figure 2). The second actuator 25 moves the gripping unit 23 in the vertical direction via the first actuator 24. The second actuator 25 is supported by the main body 20. The second actuator 25 extends in the vertical direction. The first actuator 24 reciprocates in the vertical direction along the second actuator 25. The second actuator 25 is an electric actuator. The electric actuator can position the first actuator 24 at any position between the uppermost position and the lowermost position. The electric actuator has an electric motor 251 as a drive source and a mechanism that converts the drive force of the electric motor into vertical movement of the gripping unit 23. The robot controller 15 adjusts the vertical position of the first actuator 24 through control of the electric motor 251.

[0033] Figure 4 shows how the robot hand 2 holds a workpiece 9. The robot hand 2 has three types of holding configurations. The upper diagram in Figure 4 shows a first configuration in which the workpiece 9 is held by the support portion 22 and the clamping portion 23. The support portion 22 supports the workpiece 9 from below. The clamping portion 23 clamps the workpiece 9 between the support portion 22 and the clamping portion 23 in the vertical direction. The second suction portion 231 sucks the workpiece 9 from above. In the first configuration, the robot hand 2 can stably hold the workpiece 9. In particular, in a robot hand 2 in which the width of the support portion 22 is relatively narrow, clamping the workpiece 9 in the vertical direction enables the workpiece 9 to be held stably.

[0034] The clamping portion 23 can move in the vertical direction and clamp the workpiece 9 in accordance with the size of the workpiece 9.

[0035] The robot hand 2 includes two actuators, a first actuator 24 and a second actuator 25. The two actuators increase the amount of displacement of the clamping portion 23. The robot hand 2 can stably hold workpieces 9 of various sizes.

[0036] The second actuator 25 is an electric actuator that can position and maintain the position of the first actuator 24 at any position between the uppermost position and the lowermost position. As shown by the two-dot chain line in the upper view of Figure 4, while the robot hand 2 is approaching the workpiece 9, the second actuator 25 can position the clamping unit 23 in advance at a standby position. The standby position is a position where the clamping unit 23 is near the top of the workpiece 9.

[0037] Furthermore, because the first actuator 24 includes an air cylinder, the gripping unit 23 can be quickly moved from the standby position to the position where it contacts the upper part of the workpiece 9. The combination of the first actuator 24 and the second actuator 25 shortens the standby time of the robot system 1 for holding the workpiece 9, thereby improving the work efficiency of the robot system 1.

[0038] The middle diagram in Fig. 4 shows a second configuration in which the workpiece 9 is held by the support portion 22 and the first suction portion 26. The support portion 22 supports the workpiece 9 from below. The first suction portion 26 sucks the side of the workpiece 9. In the second configuration, the robot hand 2 can stably hold the workpiece 9.

[0039] The bottom diagram in Figure 4 shows a third configuration in which the workpiece 9 is held by the support portion 22, the clamping portion 23, and the first suction portion 26. The support portion 22 supports the workpiece 9 from below. The clamping portion 23 clamps the workpiece 9 between the support portion 22 and the clamping portion 23 in the vertical direction. The second suction portion 231 adsorbs the workpiece 9 from above. The first suction portion 26 adsorbs the side of the workpiece 9. In the third configuration, the robot hand 2 can hold the workpiece 9 even more stably. Note that in the third configuration, adsorption by the second suction portion 231 may be omitted.

[0040] By stably holding the workpiece 9, the robot 11 can increase the acceleration of the movement of the robot hand 2. This improves the work efficiency of the robot system 1.

[0041] (Structure of the Auxiliary Device) As described above, the robot system 1 includes the auxiliary device 5. FIG.

[0042] The auxiliary device 5 has a first inclined portion 51 and a second inclined portion 52. The first inclined portion 51 and the second inclined portion 52 support the bottom of the workpiece 9. The first inclined portion 51 and the second inclined portion 52 are fixed to the base 50. The first inclined portion 51 and the second inclined portion 52 are inclined in the up-down direction. More specifically, the first inclined portion 51 and the second inclined portion 52 are inclined so that the front portion is upward and the rear portion is downward. The front portion is the portion of the auxiliary device 5 closer to the conveyor 14, and the rear portion is the portion of the auxiliary device 5 farther from the conveyor 14. The first inclined portion 51 and the second inclined portion 52 incline the workpiece 9 in the up-down direction.

[0043] The first inclined portion 51 and the second inclined portion 52 are aligned in the left-right direction. The first inclined portion 51 and the second inclined portion 52 are spaced apart in the left-right direction. The auxiliary device 5 has a slit 53 between the first inclined portion 51 and the second inclined portion 52. The slit 53 extends in the front-rear direction. The slit 53 opens rearward. The left-right width of the slit 53 is wider than the width of the support portion 22. As shown by the two-dot chain line in FIG. 5 , the support portion 22 of the robot hand 2 can be inserted into the slit 53 from the rear of the auxiliary device 5. As described below, when the first inclined portion 51 and the second inclined portion 52 support the workpiece 9, the support portion 22 can be positioned within the slit 53. The support portion 22 within the slit 53 is positioned below the workpiece 9. The slit 53 also opens upward. As the robot hand 2 moves upward, the support portion 22 within the slit 53 can move upward through the upward opening and out of the slit 53. When the support section 22 moves upward, the workpieces 9 are transferred from the first inclined section 51 and the second inclined section 52 to the support section 22 .

[0044] The auxiliary device 5 has a first stopper 54 and a second stopper 55. The first stopper 54 and the second stopper 55 abut against the sides of the workpiece 9 supported by the first inclined portion 51 and the second inclined portion 52. The first stopper 54 is integrated with the rear portion of the first inclined portion 51. The first stopper 54 protrudes upward from the rear portion of the first inclined portion 51. The second stopper 55 is integrated with the rear portion of the second inclined portion 52. The second stopper 55 protrudes upward from the rear portion of the second inclined portion 52.

[0045] The workpiece 9 transported by the conveyor 14 is handed over to the auxiliary device 5 from the end of the conveyor 14. Figure 6 shows the auxiliary device 5 supporting the workpiece 9. The left view of Figure 6 is a side view of the auxiliary device 5, and the right view is a rear view of the auxiliary device 5. The bottom of the workpiece 9 is supported by the first inclined portion 51 and the second inclined portion 52. The workpiece 9 is supported by the auxiliary device 5 in an attitude inclined relative to the up-down direction. Furthermore, the leading side of the conveyor 14 in the transport direction, i.e., the side of the workpiece 9 corresponding to the rear of the auxiliary device 5, abuts the first stopper 54 and the second stopper 55. In the auxiliary device 5, the workpiece 9 is positioned at a fixed position in the front-to-rear direction.

[0046] On the other hand, the workpiece 9 is not always positioned at the same position in the left-right direction in the auxiliary device 5. This is because the position of the workpiece 9 on the conveyor 14 varies in the width direction of the conveyor 14. If the position of the workpiece 9 in the auxiliary device 5 varies, the robot 11 adjusts the position of the robot hand 2 according to the position of the workpiece 9 in the auxiliary device 5 and holds the workpiece 9. If the position of the workpiece 9 varies, the robot controller 15 determines the position of the workpiece 9 using, for example, a camera, and adjusts the position of the robot hand 2 through control of the arm 13 of the robot 11. However, adjusting the position of the robot hand 2 takes time, which reduces the work efficiency of the robot system 1.

[0047] The auxiliary device 5 has a positioning mechanism 6. The positioning mechanism 6 has a first pusher 61 and a second pusher 62. The first pusher 61 and the second pusher 62 are located on both the left and right sides of the auxiliary device 5. The first pusher 61 and the second pusher 62 face each other with the workpiece 9 in between. The first pusher 61 and the second pusher 62 can move toward each other as shown by the arrows in FIG. 7 . When the first pusher 61 and the second pusher 62 move toward each other, the contact surface of the first pusher 61 abuts against a first side surface of the workpiece 9, and the contact surface of the second pusher 62 abuts against a second side surface of the workpiece 9. The second side surface is the surface of the workpiece 9 opposite the first side surface. The workpiece 9 is pushed by each of the first pusher 61 and the second pusher 62. The workpiece 9 is positioned at a predetermined position, in this case, the center position in the left-right direction of the auxiliary device 5. The central position of the auxiliary device 5 corresponds to the position of the slit 53 .

[0048] The contact surfaces of the first pusher 61 and the second pusher 62 are also parallel to each other and have a predetermined length in the conveying direction of the workpiece 9. When the first pusher 61 and the second pusher 62 push the workpiece 9, the orientation of the workpiece 9 is corrected to be along the conveying direction of the conveyor 14.

[0049] In this way, the positioning mechanism 6 can position the workpiece 9 at a predetermined position in the auxiliary device 5.

[0050] Next, we will explain how the workpiece 9 is held in the robot system 1. First, as shown in Figure 6, when the workpiece 9 is handed over from the conveyor 14 to the auxiliary device 5, the sensor 143 of the conveyor 14 detects that the workpiece 9 has reached the auxiliary device 5. When the sensor 143 detects the workpiece 9, the conveyor 14 stops transporting.

[0051] When the workpiece 9 reaches the auxiliary device 5, the first pusher 61 and the second pusher 62 move in directions approaching each other, as shown in Fig. 7, in response to a control signal output from the robot controller 15 to the auxiliary device 5, for example. The workpiece 9 is sandwiched between the first pusher 61 and the second pusher 62, and is positioned in a predetermined orientation at a position corresponding to the slit 53. The operation of the positioning mechanism 6 is synchronized with the operation of the robot 11. The positioning of the workpiece 9 by the positioning mechanism 6 is performed while the robot 11 is performing an operation related to the transport of another workpiece 9. The standby time of the robot 11 is reduced.

[0052] After the positioning mechanism 6 has positioned the workpiece 9, the support portion 22 of the robot hand 2 is inserted into the slit 53 from rear to front, as shown in the upper diagram of Fig. 8. The support portion 22 is inserted into the slit 53 at an angle corresponding to the inclination of the first inclined portion 51 and the second inclined portion 52. Since the workpiece 9 is positioned in a position corresponding to the slit 53 in a predetermined orientation, the support portion 22 is located below the workpiece 9.

[0053] At this time, the side of the tilted workpiece 9 comes into contact with the first suction portion 26 of the robot hand 2 due to the weight of the workpiece 9. The first suction portion 26 can adsorb the side of the workpiece 9. The robot 11 can adsorb the side of the workpiece 9 simply by inserting the support portion 22 of the robot hand 2 into the slit 53.

[0054] At the timing when the support part 22 is inserted into the slit 53, the clamping part 23 is positioned at the standby position. After the support part 22 is inserted into the slit 53, the clamping part 23 moves downward and comes into contact with the upper part of the workpiece 9, as shown in the lower diagram of FIG. 8 . The second suction part 231 adsorbs the upper part of the workpiece 9. The workpiece 9 is clamped between the clamping part 23 and the support part 22, and is also adsorbed by the first suction part 26 and the second suction part 231.

[0055] 9, as the robot hand 2 moves upward, the support portion 22 moves upward through the slit 53. The workpiece 9 is transferred from the auxiliary device 5 to the robot hand 2, and the robot hand 2 stably holds the workpiece 9.

[0056] (Effects) The auxiliary device 5 can support the workpiece 9 at an inclination in the vertical direction using the first inclined portion 51 and the second inclined portion 52. The side of the workpiece 9 supported by the first inclined portion 51 and the second inclined portion 52 abuts against the first suction portion 26 of the robot hand 2 due to its own weight. The robot 11 can omit the operation of pressing the first suction portion 26 against the side of the workpiece 9. Installing the auxiliary device 5 at the end of the conveyor 14 improves the work efficiency of the robot system 1 including the conveyor 14 and the robot 11.

[0057] The auxiliary device 5 also has a first stopper 54 and a second stopper 55, which position the workpiece 9 at a predetermined position in the conveying direction in the auxiliary device 5. Since the workpieces 9 conveyed one after another by the conveyor 14 are positioned at a fixed position, the robot controller 15 does not need to check the position of the workpiece 9. The auxiliary device 5 reduces the time required to hold the workpiece 9. The robot hand 2 can hold the workpiece 9 efficiently.

[0058] Furthermore, the positioning mechanism 6 of the auxiliary device 5 positions the workpiece 9 at a predetermined position in the direction perpendicular to the conveying direction of the auxiliary device 5. The workpieces 9 conveyed one after another by the conveyor 14 are positioned at a fixed position by the positioning mechanism 6. The robot controller 15 can omit checking the position of the workpiece 9. The robot system 1 can improve work efficiency. The positioning mechanism 6 positions the workpiece 9 while the robot 11 is in the middle of an operation related to the conveyance of another workpiece 9, thereby significantly improving the conveyance efficiency of the robot system 1.

[0059] Furthermore, the clamping portion 23 and the support portion 22 of the robot hand 2 clamp the workpiece 9 in the vertical direction, so that the robot hand 2 can stably hold the workpiece 9. Furthermore, the robot hand 2 has two types of suction portions, the first suction portion 26 and the second suction portion 231, so that the robot hand 2 can hold the workpiece 9 even more stably.

[0060] The first suction portion 26 has a plurality of suction cups 261, and therefore can stably suck the side of the workpiece 9.

[0061] Because the second suction portion 231 has the contact surface 232, the clamping portion 23 can stably clamp the workpiece 9 between itself and the support portion 22. In addition, because the contact surface 232 has flexibility that allows it to deform according to the shape of the upper portion of the workpiece 9, the suction force of the second suction portion 231 is high. A high suction force is advantageous for stably holding the workpiece 9.

[0062] 11 schematically shows an auxiliary device 56 according to a modified example. The auxiliary device 56 has a changeable angle of an inclined portion 57. The inclined portion 57 supports the bottom of the workpiece 9, similar to the first inclined portion 51 and the second inclined portion 52 described above. A stopper 58 is integrated into the rear of the inclined portion 57.

[0063] The angle of the inclined portion 57 can be changed by vertically changing the position of the rear end of the inclined portion 57 with the front end serving as a fulcrum. The front end of the inclined portion 57 is located near the end of the conveyor 14.

[0064] A drive source changes the angle of the inclined portion 57. The drive source in Fig. 11 is an extendable cylinder 59. The cylinder 59 may be a fluid pressure cylinder. The cylinder 59 may be an electric cylinder. The cylinder 59 extends and retracts in response to a control signal from the robot controller 15, for example.

[0065] The tip of the rod 591 of the cylinder 59 is connected, for example, to the vicinity of the rear end of the inclined portion 57. As the rod 591 extends and contracts, the support surface 571 of the inclined portion 57 for the workpiece 9 changes between a horizontal state as shown in the lower diagram of Fig. 11 and a state in which the support surface 571 is inclined downward from the transport surface of the conveyor 14 as shown in the upper diagram of Fig. 11. When the support surface 571 is inclined, the inclined portion 57 can support the workpiece 9 at an inclination in the vertical direction, so that the side of the workpiece 9 can be brought into contact with the first suction portion 26 of the robot hand 2 by its own weight.

[0066] The robot controller 15 may tilt the inclined portion 57 during the workpiece 9 transport operation, and not tilt the inclined portion 57 at other times.

[0067] The robot controller 15 may also tilt or horizontalize the inclined portion 57 depending on the type, shape, or weight of the workpiece 9 transported to the auxiliary device 5 .

[0068] The drive source of the tilting portion 57 is not limited to the telescopic cylinder, but may be a rotating electric machine.

[0069] The robot hand that can be combined with the auxiliary device 5 is not limited to the robot hand 2 having the structure described above. For example, the robot hand 2 is not limited to one having a narrow support portion 22. Furthermore, the support portion 22 of the robot hand 2 is not limited to a fork shape including multiple placement portions 221, 222, 223, and 224. The support portion 22 of the robot hand 2 does not have to be able to move in the forward and backward directions. The second suction portion 231 of the robot hand 2 can be omitted. Furthermore, the clamping portion 23 of the robot hand 2 can be omitted.

[0070] The positioning mechanism 6 can be omitted from the auxiliary device 5. The orientation of the auxiliary device 5 installed at the end of the conveyor 14 is not limited to the orientation in which the first inclined portion 51 and the second inclined portion 52 are inclined with respect to the conveying direction of the conveyor 14 as shown in Fig. 1. The orientation of the auxiliary device 5 may be changed by 90° from the orientation shown in Fig. 1. In other words, the first inclined portion 51 and the second inclined portion 52 of the auxiliary device 5 may be inclined in a direction perpendicular to the conveying direction of the conveyor 14.

[0071] The auxiliary device 5 is not limited to having two stoppers, and may have one stopper.

[0072] Furthermore, when the robot hand 2 holds the workpiece 9 from the auxiliary device 5, the clamping portion 23 may not clamp the workpiece 9, but may hold the workpiece 9 using the support portion 22 and the first suction portion 26.

[0073] (Aspects) The above-described embodiments are specific examples of the following aspects.

[0074] (Aspect 1) An auxiliary device (5) that assists a robot hand (2) in holding a workpiece (9), comprising: inclined portions (51, 52) that support the bottom of the workpiece (9) and tilt the workpiece (9) in the vertical direction, thereby causing the side of the workpiece (9) to abut against a suction portion (26) of the robot hand (2) by the weight of the workpiece (9); and a slit (53) that positions a support portion (22) of the robot hand (2) below the workpiece (9) supported by the inclined portions (51, 52) and allows the support portion (22) to move upward so that the workpiece (9) can be transferred from the inclined portions (51, 52) to the support portion (22).

[0075] The weight of the workpiece (9) causes the side of the workpiece (9) to come into contact with the suction portion (26), which allows the suction portion (26) to adsorb the side of the workpiece (9), and therefore the robot hand (2) can quickly hold the workpiece (9) supported by the auxiliary device (5).

[0076] (Aspect 2) The auxiliary device (5) according to aspect 1, wherein the inclined portions (51, 52) are located at the ends of the conveyor (14) and support the workpiece (9) transported by the conveyor (14).

[0077] The auxiliary device (5) assists the robot hand (2) in quickly holding the workpiece (9) being transported by the conveyor (14).

[0078] (Aspect 3) The auxiliary device (5) according to Aspect 2, further comprising a positioning mechanism (6) that positions the workpiece (9) supported on the inclined portions (51, 52) at a position where the workpiece (9) is held by the robot hand (2) in a horizontal direction perpendicular to the conveying direction of the conveyor (14) and the up-down direction.

[0079] Since the positioning mechanism (6) positions the workpiece (9) at a predetermined position in the auxiliary device (5), position adjustment of the robot hand (2) is omitted, and the robot hand (2) can quickly hold the workpiece (9).

[0080] (Aspect 4) The auxiliary device (5) according to Aspect 3, wherein the positioning mechanism (6) has a first pusher (61) and a second pusher (62) positioned on both sides of the workpiece (9) in the horizontal direction, and the first pusher (61) and the second pusher (62) push the workpiece (9) from both sides in the horizontal direction toward the center.

[0081] The two pushers (61, 62) can position the workpiece (9) at a fixed position.

[0082] (Aspect 5) The auxiliary device (5) according to any one of Aspects 2 to 4, further comprising stoppers (54, 55) that come into contact with the side portions of the workpiece (9) supported by the inclined portions (51, 52).

[0083] The stoppers (54, 55) position the work (9) at a predetermined position in the auxiliary device (5).

[0084] (Aspect 6) The auxiliary device (5) according to aspect 5, wherein the stoppers (54, 55) abut against the side portions of the workpieces (9) in the conveying direction of the conveyor (14).

[0085] The stoppers (54, 55) can position the work (9) at a predetermined position in the conveying direction.

[0086] (Aspect 7) The auxiliary device (56) according to any one of Aspects 1 to 6, wherein the inclined portion (57) has a variable inclination angle.

[0087] (Aspect 8) A robot system (1) comprising: a robot hand (2) having a support portion (22) that supports a workpiece (9) from below; and an adsorption portion (26) that adsorbs to a side of the workpiece (9) supported by the support portion (22) and holds the workpiece (9) together with the support portion (22); and an auxiliary device (5) having inclined portions (51, 52) that support the bottom of the workpiece (9) and tilt the workpiece (9) in the vertical direction so that the side of the workpiece (9) abuts against the adsorption portion (26) due to the weight of the workpiece (9), and a slit (53) that positions the support portion (22) below the workpiece (9) supported by the inclined portions (51, 52) and allows the support portion (22) to move upward so that the workpiece (9) can be transferred from the inclined portions (51, 52) to the support portion (22).

[0088] The use of an auxiliary device (5) can assist the robot hand (2) in holding the workpiece (9).

[0089] (Aspect 9) The robot system (1) according to Aspect 8, wherein the robot hand (2) further includes a clamping portion (23) that vertically clamps the workpiece (9) between the robot hand (2) and the support portion (22).

[0090] Since the workpiece (9) is held in the vertical direction, the robot hand (2) can stably hold the workpiece (9).

[0091] (Aspect 10) The robot system (1) according to aspect 9, wherein the holding unit (23) has a second suction unit (231) that suctions the workpiece (9) from above.

[0092] If the second suction portion (231) suctions the workpiece (9) from above while the workpiece (9) is held in the vertical direction, the workpiece (9) can be held even more stably.

[0093] (Aspect 11) The robot system (1) according to Aspect 10, wherein the suction portion (26) has a plurality of suction cups (261) including openings that contact the side portions of the workpiece (9) and are connected to a negative pressure supply device (31), and the second suction portion (231) has an abutment surface (232) that extends horizontally and contacts the upper portion of the workpiece (9), and a suction hole (233) that opens into the abutment surface (232) and is connected to the negative pressure supply device (31).

[0094] The suction portion (26) having a plurality of suction cups (261) can stably suck the side of the workpiece (9).

[0095] The second suction portion (231) having the contact surface (232) can stably suck the upper part of the work (9) held between it and the support portion (22).

[0096] (Aspect 12) A method for holding a workpiece (9) in a robot system (1), comprising: inclined portions (51, 52) of an auxiliary device (5) support the bottom of the workpiece (9) and tilt the workpiece (9) in the vertical direction; a robot (11) moves a support portion (22) of a robot hand (2) into a slit (53) of the auxiliary device (5) so that the support portion (22) is positioned below the workpiece (9); a side portion of the workpiece (9) abuts against a suction portion (26) of the robot hand (2) due to the weight of the workpiece (9), and the suction portion (26) adsorbs the workpiece (9); and a method for holding a workpiece (9) in a robot system (1), comprising: a robot (11) moving the support portion (22) upward, whereby the workpiece (9) is transferred from the inclined portions (51, 52) to the support portion (22), and the support portion (22) and the suction portion (26) hold the workpiece (9).

[0097] The combination of the auxiliary device (5) and the robot hand (2) having the suction part (26) increases the efficiency of work involved in transporting the workpiece (9).

[0098] (Aspect 13) The method for holding a workpiece (9) in a robot system (1) according to Aspect 12, wherein a clamping portion (23) of the robot hand (2) clamps the workpiece (9) in the vertical direction between the clamping portion (23) and the support portion (22).

[0099] By vertically clamping the workpiece (9), the robot hand (2) can stably hold the workpiece (9).

[0100] REFERENCE SIGNS LIST 1 Robot system 14 Conveyor 2 Robot hand 22 Support portion 23 Grip portion 231 Second suction portion 232 Contact surface 233 Suction hole 26 First suction portion (suction portion) 261 Suction cup 31 Negative pressure supply device 5 Auxiliary device 51 First inclined portion 52 Second inclined portion 53 Slit 54 First stopper (stopper) 55 Second stopper (stopper) 6 Positioning mechanism 61 First pusher 62 Second pusher 9 Work

Claims

1. An auxiliary device that assists a robot hand in holding a workpiece, comprising: an inclined portion that supports the bottom of the workpiece and tilts the workpiece vertically, causing the side of the workpiece to abut against the suction portion of the robot hand due to the workpiece's own weight; and a slit that positions the support portion of the robot hand below the workpiece supported on the inclined portion and allows the support portion to move upward so that the workpiece can be transferred from the inclined portion to the support portion.

2. An auxiliary device according to claim 1, wherein the inclined portion is located at the end of the conveyor and supports the workpiece transported by the conveyor.

3. An auxiliary device according to claim 2, further comprising a positioning mechanism for positioning the work supported on the inclined section in a horizontal direction perpendicular to the conveying direction of the conveyor and the vertical direction, at a position where the work can be held by the robot hand.

4. An auxiliary device according to claim 3, wherein the positioning mechanism has a first pusher and a second pusher positioned on either side of the workpiece in the horizontal direction, and the first pusher and the second pusher push the workpiece toward the center from either side of the horizontal direction.

5. An auxiliary device according to any one of claims 2 to 4, further comprising a stopper that comes into contact with the side of the work supported on the inclined portion.

6. An auxiliary device according to claim 5, wherein the stopper abuts against the side of the workpiece in the conveying direction of the conveyor.

7. An assisting device according to any one of claims 1 to 6, wherein the inclined portion has a variable inclination angle.

8. A robot system comprising: a robot hand having a support part that supports a workpiece from below, and a suction part that adsorbs to the side of the workpiece supported by the support part and holds the workpiece together with the support part; an auxiliary device having an inclined part that supports the bottom of the workpiece and tilts the workpiece in the vertical direction, causing the side of the workpiece to abut against the suction part by the workpiece's own weight, and a slit that positions the support part below the workpiece supported on the inclined part and allows the support part to move upward so that the workpiece can be transferred from the inclined part to the support part.

9. A robot system according to claim 8, wherein the robot hand further comprises a clamping portion that clamps the workpiece between the robot hand and the support portion in the vertical direction.

10. A robot system according to claim 9, wherein the clamping portion has a second suction portion that sucks the workpiece from above.

11. A robot system according to claim 10, wherein the suction part has a plurality of suction cups including openings that contact the side of the workpiece and are connected to a negative pressure supply device, and the second suction part has a contact surface that extends horizontally and contacts the top of the workpiece, and a suction hole that opens into the contact surface and is connected to a negative pressure supply device.

12. A method of holding a workpiece in a robot system, in which an inclined portion of an auxiliary device supports the bottom of the workpiece and tilts the workpiece in the vertical direction; the robot moves the support portion of the robot hand into the slit of the auxiliary device, so that the support portion is positioned below the workpiece; the side of the workpiece comes into contact with the suction portion of the robot hand due to the weight of the workpiece, and the suction portion adsorbs the workpiece; the robot moves the support portion upward, so that the workpiece is transferred from the inclined portion to the support portion, and the support portion and the suction portion hold the workpiece.

13. A method for holding a workpiece in a robot system according to claim 12, wherein the clamping portion of the robot hand clamps the workpiece between itself and the support portion in the vertical direction.

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