Robot control device and robot system

Abstract

The invention provides a robot control device which can grasp at least one of the width, the depth and the height of a conveyed object by using at least two values of holding force. A robot control device that controls the operation of a robot that is provided with at least two sensors for measuring holding forces on a robot hand, holds an object placed on a first point using the robot hand, and places the object on a second point, the robot control device being provided with: at least one processor; and at least one storage device capable of storing a program to be executed, the at least one processor using the values of the at least two holding forces measured by the at least two sensors on the basis of the program to determine at least one of the width, depth, and height of the object.

Description

Technical Field

[0001] The present disclosure relates to a robot control device and a robot system, and in particular to a robot control device that controls the motion of a robot that holds and transports an object, and a robot system including the robot control device and the robot. Background Art

[0002] Patent Documents 1 and 2 describe a technology for causing a robot to stably hold and transport an object.

[0003] Patent Document 1 describes a conveying device and a conveying program that can convey cargo while stably holding the cargo.

[0004] Specifically, the conveying device described in Patent Document 1 includes a holding unit, a driving unit, a force sensor, a first acquisition unit, a determination unit, and a control unit. The holding unit holds the goods, the driving unit moves the holding unit, and the force sensor detects the force applied between the holding unit and the driving unit. The first acquisition unit acquires holding information indicating the holding state of the holding unit holding the goods. The determination unit determines whether to convey the goods based on the holding information indicating the holding state of the holding unit acquired by the first acquisition unit and the detection result of the force sensor. If the determination unit determines that the goods are to be conveyed, the control unit causes the driving unit to convey the goods.

[0005] Patent Document 2 describes a food holding device that can reliably hold food in a limited work space and improve the efficiency of the food loading operation.

[0006] Specifically, Patent Document 2 describes a food holding device for containing food in a bag. The holding device comprises multiple pairs of holding members configured to sandwich and hold the top portions of a plurality of food bags stacked at predetermined positions and in a predetermined direction. Two pairs of holding members adjacent to each other in the predetermined direction are located at different positions in a direction orthogonal to the predetermined direction.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-58175

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2019-922 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] When a robot transports objects such as cargo to a predetermined location for loading, if the loading condition is poor, such as if the previously loaded objects are misaligned or if objects of varying shapes are loaded, attempting to load the objects could cause the robot to collapse. Furthermore, if loading is difficult, the robot may idle without performing suction.

[0013] Therefore, a robot control device and a robot system are desired, which can place the object to be loaded at the optimal position when loading an object with a different shape of at least one of width, depth, and height on an already loaded object.

[0014] Means for solving problems

[0015] A first representative embodiment of the present disclosure is a robot control device that controls the operation of a robot, wherein the robot includes at least two sensors in a manipulator that respectively measure a holding force, and uses the manipulator to hold an object placed at a first location, lift the object, and place the object at a second location. The robot control device includes:

[0016] at least one processor;

[0017] at least one storage device capable of storing a program to be executed by the at least one processor,

[0018] The at least one processor calculates at least one of the width, depth, and height of the object using the at least two holding force values ​​measured by the at least two sensors in accordance with the program.

[0019] A representative second aspect of the present disclosure is a robot system including:

[0020] The robot control device of the first aspect; and a robot controlled by the robot control device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a configuration diagram showing a configuration example of a robot system according to one embodiment of the present invention.

[0022] Figure 2 This is a bottom view of the suction hand as viewed from the side where multiple suction pads are arranged.

[0023] Figure 3 It is a diagram explaining the transportation of goods between pallets by the suction hand.

[0024] Figure 4 This figure shows the transport path of goods using the suction hand.

[0025] Figure 5 This is a diagram showing a situation in which the suction hand is tilted relative to the cargo during the suction operation.

[0026] Figure 6 This diagram shows a situation in which the suction hand deviates from the object during the suction operation.

[0027] Figure 7 This is a diagram showing a method for suppressing cargo from leaving the adsorption pad.

[0028] Figure 8 This is a diagram showing another method of suppressing the cargo from leaving the adsorption pad.

[0029] Figure 9 This is a bottom view of the suction arm with the cargo sucked in, viewed from the side where multiple suction pads are arranged.

[0030] Figure 10 (A) to (C) are partially enlarged views of the area centered on the negative pressure sensor 1022A in the states where cargoes of different sizes are adsorbed.

[0031] Figure 11 This is a bottom view of the suction hand with the cargo sucked in, viewed from the side where the multiple suction pads are arranged, in a state where the center of the suction hand does not coincide with the center of the cargo.

[0032] Figure 12 This is a diagram explaining the operation of loading cargo to the optimal position on the pallet using the suction hand.

[0033] Figure 13 This is a flowchart showing the control operation of the robot control device.

[0034] Figure 14 This is a block diagram showing a configuration example in which a robot control device is configured by a computer. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present disclosure will be described in detail using the accompanying drawings.

[0036] Figure 1 This is a configuration diagram showing a configuration example of a robot system according to one embodiment of the present invention.

[0037] like Figure 1 As shown, the robot system 10 includes a robot 100 that transports an object and a robot control device 200 that controls the operation of the robot 100. The robot 100 and the robot control device 200 are connected via a cable.

[0038] The robot 100 includes a robot mechanism 101 and a suction hand 102 attached to the front end of the robot mechanism 101. The suction hand 102 serves as a manipulator.

[0039] The robot mechanism 101 has multiple joint axes, each of which is equipped with a motor. Each motor is controlled by an operation command from the robot control device 200. By controlling each motor, the robot mechanism 101 can move the suction hand 102 in the vertical and horizontal directions.

[0040] The suction hand 102 includes a vacuum generator, a regulator that generates negative pressure (a pressure difference in the negative direction relative to atmospheric pressure), and multiple negative pressure sensors that measure the negative pressure. The negative pressure sensors serve as sensors for measuring holding force. The suction hand 102 includes multiple suction pads (also called vacuum pads) 1021, which are internally negatively pressured by the vacuum generator and regulator. By creating negative pressure within the multiple suction pads 1021, the multiple suction pads 1021 attract the surface of the cargo, thereby conveying the cargo.

[0041] Although the suction hand 102 includes a regulator to control the negative pressure, the negative pressure may fluctuate depending on the shape of the object being conveyed, the gripping state of the suction hand 102, and the surrounding conditions. When the negative pressure fluctuates, the force with which the suction hand 102 grips the object 300 (hereinafter referred to as the gripping force) also fluctuates. The negative pressure represents the gripping force, and this gripping force serves as the gripping force.

[0042] Figure 2 This is a bottom view of the suction hand as viewed from the side where multiple suction pads are arranged.

[0043] Figure 2 The suction hand 102 shown in the figure has 56 suction pads 1021 arranged in 8 columns and 7 rows, and five negative pressure sensors 1022A through 1022E for measuring negative pressure. Negative pressure sensors 1022A, 1022B, 1022D, and 1022E each measure the negative pressure on four suction pads. Negative pressure sensor 1022C also measures the negative pressure on approximately four suction pads.

[0044] Although an example in which the number of negative pressure sensors is five is shown here, the number of negative pressure sensors may be two or more, and negative pressure sensors may be provided for each of the plurality of adsorption pads 1021 .

[0045] A regulating valve is provided in each of the plurality of adsorption pads 1021. The regulating valve closes when the pressure becomes high, suppressing leakage between the adsorption pad and the cargo. Even in the case of an adsorption pad not facing the cargo, the negative pressure can still be prevented from decreasing, and the cargo can be transported.

[0046] Below, use Figure 3 and Figure 4, explaining the conveying action of goods by the suction hand.

[0047] Figure 3 It is a diagram explaining the transportation of goods between pallets by the suction hand. Figure 4 This is a diagram showing the transport path of goods by the suction hand. Figure 3 In FIG, positions A1, A2, B2, and B1 indicate the positions where the suction pad 1021 located at the center of the suction hand 102 contacts the cargo 300. Positions A1, A2, B2, and B1 change when the cargo being transported changes, and the cargo transport path also changes.

[0048] The robot control device 200 controls the conveying operation of the suction hand 102 and the suction and detachment operations of the suction hand 102 performed by the robot mechanism 101 .

[0049] like Figure 4 As shown, the suction hand 102 conveys the package 300 placed on the pallet 400A to the pallet 400B along the conveying path of the package 300 in the order of positions A1, A2, B2, and B1.

[0050] At position A1 , the robot control device 200 causes the suction hand 102 to suck the object 300 , and between positions A1 and A2 , the suction hand 102 conveys (lifts) the object 300 in the vertical direction.

[0051] The robot controller 200 then causes the suction hand 102 to horizontally transport the cargo 300 between positions A2 and B2, and to vertically transport (lower) the cargo 300 between positions B2 and B1. The robot controller 200 also causes the suction hand 102 to place, detach, and then load the cargo 300 at position B1. In this embodiment, the first position is, for example, position A1 on the pallet 400A. The second position is, for example, position B1 on the pallet 400B.

[0052] exist Figure 3 and Figure 4 , although the initial action of the suction hand 102 placing the cargo 300 is shown in a state where no cargo is placed on the pallet 400B, in the second and subsequent actions of the suction hand 102 placing the cargo 300, the pallet 400B is placed with cargo.

[0053] The robot control device 200 performs the following operations in the conveyance path of the cargo 300 at the positions A1, A2, B2, and B1 in this order.

[0054] (1) At position A1 where the suction operation is performed, the robot control device 200 measures the negative pressure using the negative pressure sensors 1022A-1022E of the suction hand 102. The robot control device 200 determines that the suction hand 102 is separated from the object 300 at a location where the negative pressure is low, and changes the posture of the suction hand 102 to press the suction hand 102 toward the location where the negative pressure is low.

[0055] Thereafter, between positions A1 and A2 where the operation of conveying the package in the vertical direction is performed, the robot control device 200 raises the suction hand 102 that has sucked the package 300 .

[0056] (2) Between positions A2-B2 where the action of transporting goods in the horizontal direction is performed, if there is a smaller negative pressure value among the five negative pressure values ​​measured by the negative pressure sensors 1022A-1022E, the robot control device 200 causes the robot 100 to move so that the smaller negative pressure value is increased.

[0057] (3) Between positions B2 and B1 where the vertical conveying (lowering) operation is being performed, or at position B1 where the cargo 300 is placed, the robot control device 200 measures the negative pressure values ​​of the negative pressure sensors 1022A to 1022E to thereby determine the width and depth of the cargo 300. "Width" and "depth" are sometimes also referred to as "length" and "width," respectively. The width and depth of the cargo 300 can also be determined at position A1 or between positions A2 and B2.

[0058] When the cargo 300 is placed at the position B1 , the negative pressure value of each negative pressure sensor increases, and thus the robot control device 200 can grasp the height of the cargo 300 .

[0059] (4) After determining the width, depth, and height of the cargo 300, the robot control device 200 determines the weight of the cargo 300 based on the torque of the joint axis motor, as described below. The robot control device 200 calculates the optimal loading position taking into account the four parameters of the cargo 300: width, depth, height, and weight, and then loads the cargo 300.

[0060] The following further describes in detail the suction operation at position A1, the horizontal conveying operation between positions A2 and B2, and the vertical conveying operation between positions B2 and B1, or the loading (placement) operation at position B2.

[0061] (Adsorption action)

[0062] At position A1, the robot controller 200 measures the negative pressure values ​​of the negative pressure sensors 1022A to 1022E of the suction hand 102 while it is holding the object 300, and calculates the difference in the negative pressure values ​​measured by the negative pressure sensors 1022A to 1022E. The robot controller 200 then adjusts the posture or position of the suction hand 102 relative to the object 300 to eliminate the difference in negative pressure values, and then causes the suction hand 102 to hold the object 300.

[0063] For example, Figure 5 As shown, when the suction hand 102 is tilted relative to the cargo 300, a difference in negative pressure values ​​occurs between the negative pressure sensors 1022A and 1022B, and between the negative pressure sensors 1022C and 1022D. In this case, the robot control device 200 determines that the cargo 300 is being loaded at an angle and controls the robot mechanism 101 to eliminate the difference in negative pressure values ​​between the negative pressure sensors 1022A and 1022B, and between the negative pressure sensors 1022C and 1022D. As a result, the suction hand 102 changes its position to become parallel to the cargo 300.

[0064] When the suction hand 102 suctions the cargo 300, even if the negative pressure values ​​of the negative pressure sensors 1022A to 1022E (values ​​that become the holding force) are respectively greater than the predetermined value (the predetermined holding force value), if the suction surface of the cargo 300 (the holding surface) is smaller than the predetermined value (the predetermined holding surface value), it is preferred to reposition the suction hand 102 so that the negative pressure values ​​of the negative pressure sensors 1022A to 1022E are respectively greater than the predetermined value (the predetermined holding force value) and the suction surface of the cargo is greater than the predetermined value (the predetermined suction surface value).

[0065] For example, Figure 6 As shown, when the cargo 300 is offset from the bottom surface of the suction hand 102 equipped with 56 suction pads, and the surface of the cargo 300 being sucked (the suction surface) is reduced, the regulating valves of the suction pads that are offset from the suction surface are closed, thereby suppressing leakage from the suction pads. Therefore, even if the suction surface of the cargo 300 is small, the negative pressure values ​​(holding force values) of all the negative pressure sensors 1022A-1022E are still greater than the predetermined value (the predetermined holding force value). Figure 6 In the diagram, the adsorption pad with the closed regulating valve is represented by a circle with an inner slash.

[0066] However, when the suction surface of the cargo 300 is smaller than the predetermined value (predetermined value of the holding surface), Figure 6In the case shown, since only 24 of the 56 adsorption pads contribute to adsorption, the repositioning of the adsorption hand 102 is performed as described later. Figure 9 The configuration shown is configured so that the negative pressure values ​​of negative pressure sensors 1022A-1022E each exceed a predetermined value (predetermined holding force value), and the cargo suction surface exceeds a predetermined value (predetermined suction surface value). Whether the suction surface of cargo 300 is smaller than the predetermined holding surface value can be determined based on the negative pressure values ​​of negative pressure sensors 1022A-1022E. If there is little leakage from the suction pads closed by the control valves, the negative pressure increases as the number of suction pads closed by the control valves increases. Therefore, the number of suction pads closed by the control valves can be determined by measuring the negative pressure values, and the size of the suction surface of cargo 300 can be determined by evaluating the size of the un-suctioned surface.

[0067] For example, if you compare Figure 6 The adsorption state is similar to that described later. Figure 9 The adsorption state of Figure 6 In the adsorption state, since the adjustment valves of the four adsorption pads corresponding to the negative pressure sensors 1022A and 1022B are all closed, the negative pressure of the negative pressure sensors 1022A and 1022B is Figure 6 The adsorption state ratio Figure 9 The adsorption state is higher. In addition, Figure 6 In the adsorption state, the number of closed adjustment valves among the adjustment valves of the four adsorption pads corresponding to the negative pressure sensors 1022D and 1022E is Figure 6 The adsorption state ratio Figure 9 The adsorption state is less than 1, so the negative pressure of negative pressure sensors 1022D and 1022E is Figure 6 The adsorption state ratio Figure 9 In addition, the adsorption state is smaller. Figure 6 In the adsorption state, since the adjustment valves of the four adsorption pads corresponding to the negative pressure sensor 1022C include the closed adjustment valve, the negative pressure of the negative pressure sensors 1022D and 1022E is Figure 6 The adsorption state ratio Figure 9 The adsorption state is higher.

[0068] Therefore, by measuring the negative pressure values ​​of negative pressure sensors 1022A, 1022B, 1022D, and 1022E, the number of adsorption pads closed by the regulating valve can be almost known, and the size of the adsorption surface of the cargo 300 can be evaluated by calculating the number of remaining adsorption pads.

[0069] (Horizontal conveying action)

[0070] After the suction hand 102 is raised from position A1 to position A2, the robot control device 200 measures the negative pressure values ​​of the negative pressure sensors 1022A to 1022E of the suction hand 102 during the horizontal transport (movement) interval between positions A2 and B2, thereby determining the difference in the negative pressure values ​​measured by the negative pressure sensors 1022A to 1022E. If the difference in the negative pressure values ​​exceeds a certain value or increases, the robot control device 200 determines that the cargo 300 has begun to leave the suction pad 1021, and controls the robot mechanism 101 to prevent the cargo 300 from leaving the suction pad 1021.

[0071] For example, similar to the suction operation at position A1, suppose that a difference in negative pressure values ​​occurs between negative pressure sensor 1022A and negative pressure sensor 1022B, and between negative pressure sensor 1022C and negative pressure sensor 1022D, during the horizontal transport (movement) section between positions A2 and B2. In this case, the robot control device 200 determines that the cargo 300 has begun to leave the suction pad 1021 and controls the robot mechanism 101 so that the difference in negative pressure values ​​between negative pressure sensor 1022A and negative pressure sensor 1022B, and between negative pressure sensor 1022C and negative pressure sensor 1022D, disappears or decreases.

[0072] The method by which the robot control device 200 controls the robot mechanism 101 so that the cargo 300 does not leave the suction pad 1021 is not particularly limited, but there are the following two methods, for example.

[0073] (1) Figure 7 As shown, the robot mechanism 101 rotates and tilts the suction hand 102 holding the cargo 300 counterclockwise and accelerates in the conveying direction. Thus, the force pressing the cargo 300 against the suction hand 102 acts to prevent the cargo 300 from leaving the suction pad 1021.

[0074] (2) Figure 8 As shown, the robot mechanism 101 rotates the suction hand 102 holding the object 300 by 180 degrees. This causes the object 300 to be pressed against the suction hand 102 by gravity, preventing the object 300 from leaving the suction pad 1021. When the suction hand 102 reaches position B2, the robot mechanism 101 rotates the suction hand 102 holding the object 300 by 180 degrees, returns it to its original position, and then moves it vertically (descends).

[0075] (Vertical conveying or loading action)

[0076] The robot controller 200 determines the width, depth, and height of the cargo 300 based on the values ​​measured by the negative pressure sensors 1022A-1022E, between positions B2 and B1 for vertical conveyance or at position B1 for loading (placement). Furthermore, the robot controller 200 determines the weight of the cargo 300 at position B1.

[0077] First, the operation of grasping the width and depth of the cargo 300 will be described.

[0078] Figure 9 This is a bottom view of the suction arm with the cargo sucked in, viewed from the side where multiple suction pads are arranged. Figure 10 (A) to (C) are partial enlarged views of the area centered on the negative pressure sensor 1022A in the states where cargoes of different sizes are adsorbed.

[0079] like Figure 9 As shown, when the area of ​​the cargo 300 is smaller than the area of ​​the bottom surface of the suction hand 102 on which 56 suction pads 1021 are arranged, the 26 suction pads arranged on the four sides closest to the bottom surface of the suction hand 102 cannot absorb the cargo 300, and the regulating valves provided for each suction pad 1021 are closed, thereby suppressing leakage from the suction pad 1021. Figure 9 In FIG. 1 , the adsorption pad 1021 with the regulating valve closed is represented by a circle with an inner slant line.

[0080] like Figure 9 As shown, when the cargo 300 has been sucked by the suction hand 102, for example, when focusing on the negative pressure sensor 1022A, as shown in FIG. Figure 10 As shown in (A) in FIG. 3 , three of the four adsorption pads 1021 are closed by the regulating valves, and leakage occurs between one adsorption pad 1021 and the cargo 300. The negative pressure measured by the negative pressure sensor 1022A at this time is referred to as P1.

[0081] On the other hand, when the area of ​​the bottom surface of the suction hand 102 is almost equal to the area of ​​the object 300 to be sucked, and the bottom surface of the suction hand 102 overlaps with the surface of the object 300, for example, when focusing on the negative pressure sensor 1022A, as shown in FIG. Figure 10 As shown in (B), the leakage occurs between the four adsorption pads and the cargo. The negative pressure measured by the negative pressure sensor 1022A at this time is referred to as P2.

[0082] The area ratio of the adsorbed goods 300 to the bottom surface of the adsorption hand 102 is Figure 9 When the area shown is smaller, for example, when focusing on the negative pressure sensor 1022A, as shown in FIG. Figure 10As shown in (C), the four adsorption pads are closed by the regulating valves, and no leakage occurs between the adsorption pads and the cargo. The negative pressure measured by the negative pressure sensor 1022A at this time is referred to as P3.

[0083] If there is almost no leakage from the adsorption pad 1021 closed by the regulating valve, Figure 10 The negative pressure value P1 measured in the state (A) is Figure 10 The negative pressure value P2 measured in the state (B) is Figure 10 The negative pressure value P3 measured in the state (C) has the relationship of P3>P1>P2.

[0084] If the negative pressures measured by the negative pressure sensors 1022A, 1022B, 1022D, and 1022E are all P1, Figure 9 As shown, it can be inferred that the depth D of the cargo is the arrangement length of 5 adsorption pads 1021, and the width W of the cargo is inferred to be the arrangement length of 6 adsorption pads 1021.

[0085] If the negative pressures measured by the negative pressure sensors 1022A, 1022B, 1022D, and 1022E are all P2, it can be inferred that the depth D of the cargo is the arrangement length of the seven adsorption pads 1021, and the width W of the cargo is the arrangement length of the eight adsorption pads 1021.

[0086] If the negative pressures measured by negative pressure sensors 1022A, 1022B, 1022D and 1022E are all P3, and the negative pressure measured by negative pressure sensor 1022A is P3, then the depth D of the cargo is estimated to be the arrangement length of 3 adsorption pads 1021, and the width W of the cargo is estimated to be the arrangement length of 4 adsorption pads 1021.

[0087] Figure 9 The example shown is an example of a case where the center of the suction hand is aligned with the center of the goods, but if Figure 11 As shown, even when the center of the suction hand 102 does not coincide with the center of the cargo 300 , the depth D and width W of the cargo can still be estimated. Figure 11 The goods 300 shown are Figure 9 The cargo 300 shown is a smaller cargo.

[0088] exist Figure 11 In the configuration of the suction arm 102 and the cargo 300 shown, if the negative pressure measured by the negative pressure sensors 1022A and 1022B is P1, the negative pressure measured by the negative pressure sensors 1022D and 1022E is P3, and the negative pressure measured by the negative pressure sensor 1022A is P2, then it can be inferred that the depth D of the cargo is the arrangement length of the four suction pads 1021, and the width W of the cargo is inferred to be the arrangement length of the six suction pads 1021.

[0089] While the example described above uses five negative pressure sensors, the depth and width of the cargo can be estimated with two or more negative pressure sensors. For example, if two negative pressure sensors, 1022A and 1022D, are installed, rotating the suction hand 102 90 degrees allows estimation of the depth and width of the cargo.

[0090] To more accurately determine the depth D and width W of the cargo, a negative pressure sensor can be installed on each suction pad. In this case, instead of installing a negative pressure sensor on all suction pads, a negative pressure sensor can be installed on a portion of the suction pads.

[0091] Furthermore, when the depth D and width W of the cargo 300 are desired to be known, they can be known during the vertical conveying operation between the positions B2 and B1. Alternatively, the depth D and width W of the cargo 300 can be known after the cargo is loaded once at the loading location.

[0092] In the above description, both the depth D and width W of the cargo are grasped, but only one of them may be grasped. In addition, instead of grasping both the depth D and width W of the cargo, only the height of the cargo described below may be grasped.

[0093] Next, the operation of grasping the height of the cargo will be described.

[0094] When the cargo 300 is placed on the pallet at position B1, the weight of the cargo 300 is no longer applied to the suction hand 102. Therefore, the suction hand 102 comes into close contact with the cargo 300, and the measured negative pressure value increases. At this point, the height h of the suction pad tip of the suction hand 102 is the sum of the pallet height h1 (or the pallet plus the height of the load) and the cargo height h2. Therefore, the cargo height h2 can be calculated by subtracting h from h1.

[0095] Next, the operation of grasping the weight of the cargo will be described.

[0096] Between positions B2 and B1, the robot controller 200 controls the motor of the joint axis to move (lower) the cargo 300. When the cargo 300 is stopped and placed on the pallet, no acceleration or deceleration forces are applied, and the motor torque depends on the weight of the cargo 300. Since the motor torque can be calculated by multiplying the torque constant by the current value, the robot controller 200 can determine the motor torque by detecting the current flowing through the motor, thereby determining the cargo weight.

[0097] A device for determining the torque of a motor to grasp the weight of a load is described in, for example, Japanese Patent Application Laid-Open No. 2020-151812.

[0098] The above description has been given of the operation of the robot control device 200 in the position between B2 and B1 or at position B1 to ascertain the width, depth, height, and weight of the cargo based on the measurement values ​​of the negative pressure sensor.

[0099] Next, a method of calculating an optimal loading position based on the width, depth, height, and weight of the cargo and loading the transported cargo at the calculated position will be described.

[0100] The robot control device 200 stores the width and depth of the cargo 300 on the pallet 400B, the height and weight of the load, and the position (disposition) of the cargo 300 on the load as a loading condition in the storage unit. Figure 14 The memory 221 is shown.

[0101] like Figure 2 and Figure 3 As shown, the robot control device 200 calculates the width and depth of the upper portion of the load on the pallet 400 and the height and weight of the load based on the width, depth, height, and weight of the already conveyed load 300 each time the load 300 is sequentially stacked on the pallet 400B. The robot control device 200 also continuously updates the loading status along with the position (disposition) of the load on the load. The width and depth of the upper portion of the load on the pallet 400 and the position (disposition) of the load on the load constitute information representing the shape of the load.

[0102] The height of the load is the height from the surface of the pallet 400B or the surface on which the pallet 400B is installed (the ground, floor, etc.) to the surface of the cargo 300 located above the load. The weight of the load is the weight of the cargo 300 located from the surface of the pallet 400B to the top of the load, and the distribution of the load weight as viewed from above is stored.

[0103] The robot controller 200 determines the width, depth, height, and weight of the cargo delivered from position P1, either between positions B2 and B1 or at position B1. The robot controller 200 then reads the loading status of the cargo on the pallet from a storage unit and calculates the optimal loading position (loading location) based on the loading status and the width, depth, height, and weight of the delivered cargo. The robot controller 200 then loads the delivered cargo at the calculated loading position.

[0104] For example, Figure 12As shown in the left figure, the robot controller 200, between positions B2 and B1 or at position B1, determines the width, depth, height, and weight of the cargo 300A delivered from position P1. The robot controller 200 reads the loading status of the cargo already loaded on the pallet 400B from the storage unit, determines whether there is space next to the cargo 300B on the pallet 400B, and determines whether the cargo 300A can be placed next to the cargo 300B based on the width, depth, and height of the cargo 300A. Furthermore, the robot controller 200 determines whether the cargo 300A can be placed next to the cargo 300B based on the weight of the cargo 300A. If the robot controller 200 determines that the cargo 300A can be placed next to the cargo 300B on the pallet 400B, it updates the loading status stored in the storage unit to include the already loaded cargo 300A.

[0105] Next, the robot controller 200 determines the width, depth, height, and weight of the cargo 300C conveyed from position P1, either between positions B2 and B1 or at position B1 (the surface of cargo 300A). The robot controller 200 then reads the loading status of cargo 300A and cargo 300B already loaded on pallet 400B from the storage unit.

[0106] The robot controller 200 determines whether to place the load on either load 300A or load 300B based on the width, depth, height, and weight of load 300C. Since it is desirable to minimize the gaps between loads on pallet 400B, the robot controller 200 considers the width and depth of load 300C when determining placement. Furthermore, the robot controller 200 considers the height of load 300C to minimize variations in the load's height from pallet 400B. Furthermore, the robot controller 200 considers the weight of load 300C to minimize any weight imbalance on pallet 400B.

[0107] exist Figure 12 The figure on the right side of FIG. 1 shows an example in which the robot control device 200 loads the cargo 300C on the cargo 300B based on the width, depth, height, and weight of the cargo 300C.

[0108] Next, the control operation of the robot control device will be described.

[0109] Figure 13 This is a flow chart showing the control actions of the robot control device. Figure 4 As shown, the robot control device 200 controls the suction hand 102 to transport the article 300 along the transport path in the order of positions A1, A2, B2, and B1.

[0110] In step S10, the robot control device 200 measures the negative pressure values ​​of the negative pressure sensors 1022A~1022E of the suction hand 102, and after adjusting the configuration (posture) of the suction hand 102 relative to the cargo 300 in a manner that eliminates the difference in the negative pressure values, causes the suction hand 102 to suction the cargo 300.

[0111] In step S11, the robot control device 200 raises the suction hand 102 from position A1 to position A2. In the horizontal conveying section between positions A2 and B2, the robot control device 200 controls the suction hand 102 so that the cargo 300 does not leave the suction hand while moving it horizontally (horizontally conveying it). The robot control device 200 controls the suction hand 102 so that the cargo 300 does not leave the suction hand 102, for example, as follows.

[0112] The robot control device 200 measures the negative pressure values ​​of the negative pressure sensors 1022A to 1022E of the suction hand 102 and determines the difference between the measured negative pressure values. If the difference in the negative pressure values ​​exceeds a fixed value or if the difference in the negative pressure values ​​fluctuates, the robot control device 200 determines that the cargo 300 has begun to leave the suction pad 1021 and controls the robot mechanism 101 to prevent the cargo 300 from leaving the suction pad 1021.

[0113] In step S12 , the robot control device 200 ascertains the width, depth, height, and weight of the cargo during the vertical conveyance (descent) of the suction hand 102 or at the placement position.

[0114] As already described, the width and depth of the cargo are calculated based on the negative pressure values ​​of the negative pressure sensors 1022A to 1022E of the suction hand 102. As already described, the height of the cargo is calculated based on the changes in the negative pressure values ​​of the negative pressure sensors 1022A to 1022E of the suction hand 102. As already described, the weight of the cargo is calculated based on the torque of the motors of the robot's joint axes.

[0115] In step S13, the robot control device 200 reads the loading status of the cargo from the storage unit, calculates the optimal loading position based on the width, depth, height and weight of the conveyed cargo obtained in step S12, and loads the conveyed cargo to the calculated position.

[0116] In step S14 , the robot control device 200 updates the loading status stored in the storage unit to the loading status including the loaded cargo.

[0117] In step S15 , the robot control device 200 detaches the suction hand 102 from the cargo 300 .

[0118] In step S16, the robot controller 200 determines whether to load the next item. If so, the process returns to step S10. If not, the process ends. Steps S10 through S16 are repeated, and the loading status of the items stored in the storage unit is continuously updated as items are stacked on the pallet.

[0119] Through the operations of the above steps S10 to S16 , the cargo 300 is transferred from the pallet 400A to the pallet 400B.

[0120] The components included in the robot control device of the embodiment described above can be implemented by hardware, software, or a combination thereof. Here, implementation by software means that the computer reads a program and executes it.

[0121] In order to realize the structural parts included in the robot control device through software or a combination thereof, the robot control device has a processor such as a CPU (Central Processing Unit). The processor functions as an execution unit. The robot control device can also have multiple processors that operate in parallel. In addition, the robot control device also has an auxiliary storage device such as an HDD (Hard Disk Drive) that stores various programs such as application software or OS (Operating System), and a processor using Figures 5 to 13 The described method for storing data for executing functions of the robot control device and Figure 8 A main storage device such as a RAM (Random Access Memory) stores programs required for operation and data temporarily required by the programs. The robot control device may also have multiple main storage devices. For example, the stored data includes information about the transport path from position A1, which is the first location, to position B1, which is the second location. This information includes the coordinates of positions A1, A2, B2, and B1. Positions A1, A2, B2, and B1 change when the transported goods change, and the transport path of the goods also changes.

[0122] The robot control device then uses a processor to read application software or an operating system from the auxiliary storage device, expand the read application software or OS onto the main storage device, and perform calculations based on the application software or OS. Furthermore, the various hardware components of the robot control device are controlled based on the results of these calculations. This is how the functional blocks of this embodiment are implemented.

[0123] Figure 14 This is a block diagram showing a configuration example in which a robot control device is configured by a computer.

[0124] like Figure 14 As shown, the computer serving as the robot control device includes a memory 221 serving as a main storage device, a CPU 222 serving as a processor, an I / O unit 223 for connecting to the robot 100 via a cable, a magnetic disk device 224 such as an HDD serving as an auxiliary storage device, and a display unit 225. The display unit 225 displays information such as the number of times cargo has been transported and the loading status.

[0125] The components included in the robot control device can be implemented using hardware including electronic circuits. When the robot control device is implemented using hardware, some or all of the functions of the components included in the robot control device can be implemented using integrated circuits (ICs), such as ASICs (Application Specific Integrated Circuits), gate arrays, FPGAs (Field Programmable Gate Arrays), and CPLDs (Complex Programmable Logic Devices).

[0126] The program can be stored and provided to the computer using various types of non-transitory computer-readable media (non-transitory computerreadable medium). Non-transitory computer-readable media include various types of tangible recording media (tangible storage medium). Examples of non-transitory computer-readable media include magnetic recording media (such as hard disks), optical magnetic recording media (such as magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, semiconductor memories (such as mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory)). In addition, the program can also be supplied to the computer via various types of transitory computer-readable media (transitory computerreadable medium).

[0127] In the present embodiment described above, the following effects can be obtained.

[0128] (1) During the adsorption operation, since the goods are adsorbed to the adsorption hand after adjusting the configuration (posture) of the adsorption hand relative to the goods, the falling of the goods 300 mainly due to the unstable adsorption state can be reduced, thereby preventing the generation of defective or defective products caused by the falling.

[0129] (2) During horizontal transport, when it is determined that the cargo begins to leave the suction pad, the robot mechanism is controlled so that the cargo does not leave the suction pad. This prevents the cargo from falling during transport.

[0130] (3) By understanding the width, depth, height, and weight of the cargo, cargo of various shapes and weights can be placed in the optimal position. Even when there are multiple cargoes with different weights, the load can be balanced between the light and heavy items.

[0131] (4) Since the loading status of the cargo can be monitored, even in the case of poor loading conditions such as cargo being misaligned or cargo of various shapes being loaded, the slope of the loading area can be monitored to prevent the cargo from collapsing. In addition, when loading of cargo is difficult, the robot can be prevented from idling when not adsorbing, thereby improving the conveying capacity.

[0132] In the above-described embodiment, instead of grasping all of the width, depth, and height of the cargo, one or more of the width, depth, and height of the cargo may be grasped as needed.

[0133] (Variation)

[0134] In the embodiment described above, a suction hand is used as a manipulator to transport goods. However, the manipulator is not limited to a suction hand. Other manipulators may include gripping hands used in prize-grabbing games, gripping hands that use negative pressure, vacuum, or pressure to grasp objects, and the like. Furthermore, a magnetic hand that uses magnetic force for suction may also be used as a manipulator.

[0135] Since grippers used in prize-grabbing game devices, where prizes are grabbed and obtained, or grippers that utilize negative pressure, vacuum, or pressure to grasp objects, can use pressure sensors to determine the degree to which the grip releases the object, the width and depth of the object can be measured. The method for measuring the width and depth of an object using a gripper will be described later using a specific example.

[0136] Furthermore, since the weight of an object is calculated by the control device, it can be determined regardless of the shape of the hand. The height of an object within the placement area can be determined by pressing the tip of the gripping hand with the hand closed. The point where the reaction force increases is the object's height.

[0137] Since magnetic grippers can detect the magnetically bonded surfaces using magnetic sensors, they can detect the width and depth of objects smaller than those in magnetic grippers during suction and transport. Similarly, the height of objects can be detected by pressing during loading.

[0138] A specific example of a gripping hand is described, for example, in Japanese Patent Application Laid-Open No. 2021-16925. This publication describes a robotic hand that has a pair of fingers that can open and close in a first direction, and another pair of fingers that can open and close in a second direction that is perpendicular to the first direction. These fingers are arranged circumferentially around the central axis of a base. The pair of fingers and the other pair of fingers are hollow and can be opened and closed by deforming according to the air pressure within each finger, thereby enabling the hand to grip an object.

[0139] The following describes a method for measuring the width and depth of an object using a gripping hand as described in Japanese Patent Application Laid-Open No. 2021-16925.

[0140] The gripping hand control unit controls the air supply to the opposing pair of fingers. After setting the finger opening angle (opening amount) to its maximum, the angle is continuously reduced. When the fingers grasp an object, the gripping force (called holding force) is detected by pressure sensors attached to the fingers. Because the finger opening angle (opening amount) depends on the air supply, the width or depth of the object can be determined by calculating the air supply when the gripping force is detected by the pressure sensors. The same operation can be performed on the other pair of fingers to determine the depth or width of the object.

[0141] The robot control device and robot system of the embodiment and its variations described above can utilize at least two holding force values ​​measured by at least two sensors to determine at least one of the width, depth, and height of a conveyed object. Consequently, even when loading objects of varying shapes, widths, depths, heights, and weights onto already loaded objects, the desired object can be placed in the optimal position.

[0142] While the present disclosure has been described above, the present disclosure is not limited to the aforementioned embodiments and modifications. These embodiments and modifications may be subject to various additions, substitutions, changes, and partial deletions without departing from the scope of the present disclosure, or without departing from the scope of the present disclosure as derived from the contents described in the claims and their equivalents.

[0143] In addition, these embodiments and modifications may be implemented in combination. For example, in the above-described embodiments, the order of each action or the order of each process is shown as an example and is not limited to this order.

[0144] The following supplementary notes are further disclosed regarding the above-mentioned embodiment and modifications.

[0145] (Note 1)

[0146] A robot control device (200) controls the movement of a robot (100), wherein the robot is provided with at least two sensors (1022A to 1022E) on a manipulator (102) for respectively measuring holding forces, and uses the manipulator to hold an object (300) placed at a first location, lift the object, and place the object at a second location, wherein the robot control device comprises:

[0147] at least one processor (222);

[0148] at least one storage device (221) capable of storing a program to be executed by the at least one processor,

[0149] The at least one processor calculates at least one of the width, depth, and height of the object using the at least two holding force values ​​measured by the at least two sensors in accordance with the program.

[0150] (Note 2)

[0151] The robot control device according to Supplement 1, wherein the at least one processor (222) calculates the height of the object (300) when the object (300) is placed at the second location.

[0152] (Note 3)

[0153] The robot control device according to Supplementary Note 1, wherein the at least one storage device (221) stores a loading condition of the object (300) before loading, including at least one of a height and a shape of the loaded object,

[0154] When loading the object at the second location, the at least one processor (222) calculates at least one of the width, depth and height of the object, and calculates the optimal loading location of the object based on at least one of the calculated width, depth and height of the object and the stored loading conditions.

[0155] (Note 4)

[0156] The robot control device according to Supplement 3, wherein the at least one processor (222) calculates the weight of the object based on the torque of the motor that moves the manipulator (102) when the object (300) is stopped and placed.

[0157] The loading condition includes information about the weight of the load,

[0158] The at least one processor determines an optimal placement location for the object based on at least one of the determined width, depth, and height of the object, the determined weight of the object, and the loading condition.

[0159] (Note 5)

[0160] A robot control device according to Note 3, wherein the at least one processor (222) calculates at least one of the width, depth and height of the object (300) when loading the object at the second location, and uses at least one of the calculated width, depth and height of the object to update the loading status stored in the at least one storage device (221).

[0161] (Note 6)

[0162] According to the robot control device described in Note 1, wherein, at the first location, when the manipulator (102) holds the object (300), the at least one processor (222) changes the posture of the manipulator so that the values ​​of the at least two holding forces are respectively greater than the predetermined holding force values.

[0163] (Note 7)

[0164] According to the robot control device described in Note 1, when the manipulator (102) holds the object (300), even if the values ​​of the at least two holding forces are respectively greater than the predetermined holding force values ​​and the holding surface of the object is smaller than the predetermined holding surface value, the at least one processor (222) still executes the repositioning of the manipulator so that the values ​​of the at least two holding forces are respectively greater than the predetermined holding force values ​​and the holding surface of the object is greater than the predetermined holding surface value.

[0165] (Note 8)

[0166] The robot control device according to claim 1, wherein, when the object is moved in the horizontal direction, when the difference in the holding force of the at least two sensors (1022A~1022E) becomes greater than a fixed value or when the difference in the negative pressure value becomes larger, the at least one processor (222) changes the conveying posture of the robot so that the difference in the holding force value disappears or decreases.

[0167] (Note 9)

[0168] The robot controller according to any one of Supplementary Notes 8, wherein the holding force changes over time.

[0169] (Note 10)

[0170] A robot system (10), comprising:

[0171] A robot control device (200) according to any one of Supplementary Notes 1 to 9; and a robot (100) controlled by the robot control device.

[0172] (Note 11)

[0173] The robot system according to Supplementary Note 10, wherein the manipulator is a suction hand that holds the object by suction.

[0174] Description of Reference Numerals

[0175] 10 Robotic System

[0176] 100 robots

[0177] 101 Robot Mechanism Department

[0178] 102 Suction Hand

[0179] 200 Robot Control Device

[0180] 221 Memory (storage device)

[0181] 222 CPU (processor)

[0182] 223 I / O Department

[0183] 224 Disk Device

[0184] 225 Display

[0185] 1021 Absorption Pad

[0186] 1022A~1022E: Negative pressure sensor

[0187] 300 goods.

Claims

1. A robot control device for controlling the movement of a robot, wherein the robot includes at least two sensors on a manipulator for respectively measuring a holding force, and uses the manipulator to hold an object placed at a first location, lift the object, and place the object at a second location, characterized in that: The robot control device comprises: at least one processor; at least one storage device capable of storing a program to be executed by the at least one processor, The at least one processor calculates at least one of the width, depth, and height of the object using the at least two holding force values ​​measured by the at least two sensors in accordance with the program.

2. The robot control device according to claim 1, characterized in that: The at least one processor calculates the height of the object when placing the object at the second location.

3. The robot control device according to claim 1, wherein: The at least one storage device stores the loading status of the object before loading, including at least one of the height and shape of the loaded object. When loading the object at the second location, the at least one processor calculates at least one of the width, depth and height of the object, and calculates the optimal loading location of the object based on at least one of the calculated width, depth and height of the object and the stored loading conditions.

4. The robot control device according to claim 3, characterized in that: The at least one processor calculates the weight of the object based on the torque of the motor that moves the robot when the object is stopped and placed. The loading condition includes information about the weight of the load, The at least one processor determines an optimal placement location for the object based on at least one of the determined width, depth, and height of the object, the determined weight of the object, and the loading condition.

5. The robot control device according to claim 3, characterized in that: When loading the object at the second location, the at least one processor calculates at least one of the width, depth, and height of the object, and uses the calculated at least one of the width, depth, and height of the object to update the loading status stored in the at least one storage device.

6. The robot control device according to claim 1, characterized in that: When the robot arm holds the object at the first location, the at least one processor changes the posture of the robot arm so that the values ​​of the at least two holding forces are equal to or greater than a predetermined holding force value.

7. The robot control device according to claim 1, characterized in that: When the manipulator holds the object, even if the values ​​of the at least two holding forces are respectively greater than the predetermined holding force values ​​and the holding surface of the object is smaller than the predetermined holding surface value, the at least one processor still executes the repositioning of the manipulator so that the values ​​of the at least two holding forces are respectively greater than the predetermined holding force values ​​and the holding surface of the object is greater than the predetermined holding surface value.

8. The robot control device according to claim 1, wherein: When the object is moved in the horizontal direction, when the difference in the holding force of the at least two sensors becomes greater than a fixed value or when the difference in the negative pressure value becomes larger, the at least one processor changes the conveying posture of the robot so that the difference in the holding force value disappears or decreases.

9. The robot control device according to any one of claims 1 to 8, characterized in that: The holding force varies over time.

10. A robot system, characterized in that: have: The robot control device according to any one of claims 1 to 9; and A robot is controlled by the robot control device.

11. The robot system according to claim 10, wherein: The robot arm is a suction arm that holds the object by suction.

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