Suction unit, and device for generating and storing data usable for controlling the same, and teaching method for teaching control of suction unit

Abstract

To provide a suction unit that can stably detect a state such as whether a workpiece having a different shape or center of gravity is about to fall or not.SOLUTION: A suction unit 10 having a suction pad 12 which sucks a workpiece W with a negative pressure created in an inner space part 11, includes a force sensor 21 for measuring the magnitude of a force that is dependent on an effective suction force equal to a force for the suction pad 12 to suck the workpiece W minus a force for the workpiece W to detach from the suction pad 12. The force sensor 21 is preferably disposed in the inside space part 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a suction unit that suctions a workpiece by negative pressure, a data generating and storing device for data that can be used to control the suction unit, and a teaching method for teaching the control of the suction unit. [Background technology]

[0002] Conventionally, many end effectors use suction units that use negative pressure to hold workpieces. These suction units use a generous amount of suction force to hold workpieces of various weights and shapes. This consumes excessive electrical energy and can damage or deform some workpieces.

[0003] In this regard, Patent Document 1 describes a device that focuses on the fact that the suction pad (suction unit) that suctions a workpiece deforms when the workpiece is suctioned, and detects the deformation of the suction pad and determines whether the workpiece is about to fall based on the degree of deformation. The device detects the deformation of the suction pad based on the measurement value of a strain sensor placed on the suction pad, and increases the suction force when the amount of deformation of the suction pad while suctioning a workpiece falls below a predetermined value. Therefore, it is possible to control the suction force to suction the workpiece with an appropriate amount of force. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-185636 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since the amount of deformation at each point on the suction pad varies depending on the shape and center of gravity of the workpiece, there is a problem in that it is not possible to reliably detect whether a workpiece whose shape and center of gravity is unknown is about to fall or not based on the amount of deformation at a specific point on the suction pad. The present invention has been made in consideration of the above circumstances, and aims to provide an adsorption unit that can detect whether or not a workpiece having a different shape or center of gravity is likely to fall stably, a data generation and storage device for data that can be used to control the adsorption unit, and a teaching method for teaching how to control the adsorption unit. [Means for solving the problem]

[0006] A suction unit according to a first aspect of the present invention that meets the above-mentioned objective is a suction unit having a suction pad that suctions a workpiece when a negative pressure is created in the internal space, and is equipped with a force sensor that measures the magnitude of a force corresponding to the magnitude of an effective suction force, which is the force with which the suction pad suctions the workpiece minus the force with which the workpiece tries to detach from the suction pad.

[0007] A data generating and storing device according to a second invention that meets the above-mentioned objective is a data generating and storing device that is equipped with an suction unit having a suction pad that suctions a workpiece when its internal space becomes negative pressure, and a force sensor that measures the magnitude of a force corresponding to the magnitude of the effective suction force, which is the force with which the suction pad suctions the workpiece minus the force with which the workpiece tries to separate from the suction pad, and that creates and stores data that can be used to control the movement and suction process of the suction unit for a unit control device that controls the movement and suction process of the suction unit, and that is equipped with a motion detection means that detects the inertial motion of the suction unit when it is not attached to the unit control device, a pressure adjustment means that adjusts the pressure in the internal space, and a memory means that stores time-series data for the measurement values ​​of the force sensor, the detection values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means.

[0008] A teaching method according to a third invention that meets the above-mentioned object is a teaching method for teaching a unit control device that controls the movement and suction process of a suction unit, which is equipped with a suction pad that suctions a workpiece by creating a negative pressure in an inner space and suctioning the workpiece, how to suction and move the workpiece with the suction unit, the teaching method comprising the steps of: holding the suction unit without being attached to the unit control device; operating pressure adjustment means that adjusts the pressure in the inner space to create a negative pressure in the inner space; suctioning the workpiece to the suction pad; and storing in memory means time-series data of the measurement values ​​of the force sensor, the detection values ​​of the inertial motion of the suction unit by the motion detection means, and the pressure adjustment by the pressure adjustment means, when the suction unit is moved; and providing to the unit control device the time-series data of the measurement values ​​of the force sensor, the detection values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means, which have been stored in the memory means. [Effects of the Invention]

[0009] The suction unit according to the first aspect of the present invention is equipped with a force sensor that measures the magnitude of the force corresponding to the effective suction force, which is the force with which the suction pad suctions the workpiece minus the force with which the workpiece tries to detach from the suction pad. Therefore, it is possible to detect whether or not a workpiece is likely to fall stably, even if the workpiece has a different shape or center of gravity.

[0010] The data generating and storing device of the second invention corresponds to the suction unit of the first invention, as it comprises a motion detection means for detecting the inertial motion of the suction unit when it is not attached to the unit control device, a pressure adjustment means for adjusting the pressure in the internal space, and a memory means for storing time series data of the measurement values ​​of the force sensor, the detection values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means.

[0011] A teaching method according to a third aspect of the invention comprises the steps of holding the suction unit in a human hand when not attached to the unit control device, manually operating the pressure adjustment means that adjusts the pressure in the inner space to create a negative pressure in the inner space, suctioning a workpiece to the suction pad, and moving the suction unit, and storing in memory means time-series data of the measurement values ​​of the force sensor, the detection values ​​of the inertial motion of the suction unit by the motion detection means, and the pressure adjustment by the pressure adjustment means; and providing to the unit control device the time-series data of the measurement values ​​of the force sensor, the detection values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means that have been recorded by the memory means, and therefore corresponds to the suction unit according to the first aspect of the invention. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are a longitudinal sectional view and an explanatory diagram of a suction pad of a suction unit according to an embodiment of the present invention, respectively. [Figure 2] 1A and 1B are block diagrams showing the connection of the control means and the data generating and storing device, respectively. [Figure 3] FIG. 10 is an explanatory diagram of forces acting on a workpiece that is being attracted. [Figure 4] 10A and 10B are explanatory diagrams of forces and moments acting on a workpiece that is being adsorbed; [Figure 5] 10A and 10B are explanatory diagrams of forces and moments acting on a workpiece that is being adsorbed; [Figure 6] 10 is a graph showing changes in the measurement value of the force sensor when a workpiece is sucked by a suction pad. [Figure 7] 10 is a graph showing changes in the measurement value of the force sensor when a workpiece sucked by a suction pad is lifted. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, embodiments of the present invention will be described with reference to the accompanying drawings to facilitate understanding of the present invention. 1(A) and 1(B), a suction unit 10 according to an embodiment of the present invention is a unit having suction pads 12 that create a negative pressure in an inner space 11 and suction the workpiece W, and is attached to a robot body (an example of a unit control device) 13 and used to suction the workpiece W. A detailed description will be given below.

[0014] As shown in Fig. 1(A), the suction unit 10 includes a metal base member 14 that is fixed to the robot body 13 by a fixture or the like. The base member 14 is disk-shaped, and has a through-hole 16 formed therein that communicates with a suction tube 15 of the robot body 13. An annular elastic body 17 is fixed to the base member 14, and an annular elastic body 18 is disposed on the opposite side of the base member 14 relative to the annular elastic body 17. In this embodiment, the suction pad 12 is composed of the base member 14 and the annular elastic bodies 17, 18, etc.

[0015] The annular elastic bodies 17, 18 are both made of resin, the base member 14 and the annular elastic bodies 17, 18 have approximately the same diameter, and the axes of the base member 14 and the annular elastic bodies 17, 18 are aligned in plan view. The inner space 11 is formed by the inner space of the annular elastic body 17 and the inner space of the annular elastic body 18, etc., and the through hole 16 formed in the base member 14 communicates with the inner space of the annular elastic body 17 (i.e., the inner space 11).

[0016] The suction pad 12 adsorbs the workpiece W with the annular elastic body 18 in contact with the workpiece W. The workpiece W is a product, part, or the like that is adsorbed by the suction pad 12, and the shape, size, and material of the workpiece W are not particularly limited. A force application member 19 formed of a disk-shaped (an example of a plate-shaped) rigid material is disposed between the annular elastic bodies 17, 18. The diameter of the force application member 19 is approximately the same as those of the base member 14 and the annular elastic bodies 17, 18, and the force application member 19 has its outer edge fixed to the annular elastic bodies 17, 18 with an adhesive over its entire periphery (attached to the suction pad 12). Thus, the force application member 19 is supported by the suction pad 12.

[0017] The inner region of the outer edge of the force applying member 19 (hereinafter also simply referred to as the "inner region") is disposed in the inner space 11, and divides the inner space 11 into the inner space of the annular elastic body 17 and the inner space of the annular elastic body 18. A plurality of through holes 20 are formed in the inner region of the force applying member 19, each allowing air to flow through. The inner spaces of the annular elastic body 17 and the annular elastic body 18 communicate with each other via the plurality of through holes 20.

[0018] Furthermore, a force sensor 21 that measures the magnitude of the force acting (given) is provided in the inner space (inner space portion 11) of the annular elastic body 17. One side of the force sensor 21 is fixed to the base member 14, and the other side is in contact with the force application member 19. As the force sensor 21, a six-axis force sensor that measures the magnitude of the force in each of the x-axis, y-axis, and z-axis directions, as well as the magnitude of the moment around each of the x-axis, y-axis, and z-axis, a three-axis force sensor that measures the magnitude of the force in each of the x-axis, y-axis, and z-axis directions, a one-axis force sensor that measures only the magnitude of the force in the z-axis direction, or the like can be used.

[0019] The type of sensor to be selected is determined based on the movement path of the workpiece W to be sucked by the suction unit 10, the shape of the workpiece W, and the like. In this embodiment, the suction unit 10 is configured to include a suction pad 12, a force application member 19, and a force sensor 21.

[0020] The robot body 13 has exhaust means 22 shown in Fig. 2(A) connected to the suction tube 15, and when the exhaust means 22 is activated, the air in the internal space 11 is exhausted to the outside via the suction tube 15. The exhaust means 22 can be configured by a vacuum pump, an electromagnetic valve, etc. As shown in FIG. 2(A), the robot body 13 is also equipped with a unit moving means 23 for moving the suction unit 10 attached to the robot body 13 and changing the orientation of the suction unit 10, and a control means 24 for controlling the exhaust means 22 and the unit moving means 23.

[0021] The unit moving means 23 can be composed of a plurality of motors etc. that move the joints of the robot body 13, and the control means 24 can be composed of a CPU, memory etc. Hereinafter, unless otherwise specified, it is assumed that the suction unit 10 is attached to the robot body 13. In the robot body 13, the exhaust means 22 is activated to create a negative pressure state in the internal space 11, so that the workpiece W in contact with the annular elastic body 18 is sucked onto the suction pad 12 (suction unit 10).

[0022] When the suction pad 12 suctions the workpiece W, a force is applied from the workpiece W suctioned to the suction pad 12 to the annular elastic body 18, and this force is transmitted directly from the annular elastic body 18 to the force application member 19. The force is transmitted to the force application member 19, which presses the force sensor 21 from the workpiece W side toward the base member 14. The force sensor 21 measures the force with which the force application member 19 presses the force sensor 21.

[0023] The greater the force applied to the annular elastic body 18 from the workpiece W, the greater the magnitude of the force measured by the force sensor 21. Therefore, the force application member 19 applies to the force sensor 21 a force of a magnitude corresponding to the magnitude of the force applied to the suction pad 12 from the workpiece W adsorbed to the suction pad 12.

[0024] Here, the effective suction force is the force with which the suction pad 12 suctions the workpiece W minus the force with which the workpiece W tries to separate from the suction pad 12 (for example, gravity acting on the workpiece W), and the magnitude of the force measured by the force sensor 21 is a force corresponding to the magnitude of the effective suction force (for example, X% of the effective suction force, where X is a positive number less than or equal to 100). In other words, the force sensor 21 measures a larger value as the effective suction force increases.

[0025] Therefore, by employing the suction unit 10, it is possible to detect the suction state of the workpiece W by the suction pad 12 without using a strain sensor or a proximity sensor. Therefore, for example, it is possible to detect whether the workpiece W being suctioned by the suction pad 12 is about to fall, and adjust the magnitude of the suction force, thereby reducing the consumption of electrical energy. Furthermore, if the workpiece W is soft, such as a strawberry, it is possible to suction the workpiece W with a suction force that does not damage the workpiece W.

[0026] In this embodiment, the force application member 19 is in contact only with the annular elastic bodies 17, 18 (suction pad 12) and the force sensor 21, and the force sensor 21 is in contact only with the base member 14 (suction pad 12) and the force application member 19. Therefore, the force applied from the workpiece W to the suction pad 12 is efficiently applied to the force sensor 21, and as a result, the force sensor 21 can stably measure a force of a magnitude corresponding to the magnitude of the force applied from the workpiece W to the suction pad 12 (that is, a force of a magnitude corresponding to the magnitude of the effective suction force).

[0027] From the viewpoint of enabling the force sensor 21 to stably measure a force of a magnitude corresponding to the magnitude of the force applied from the workpiece W to the suction pad 12, one example of a suitable configuration is one in which the force application member 19 is in contact only with the suction pad 12 and the force sensor 21, and the force sensor 21 is in contact only with the suction pad 12 and the force application member 19, but the configuration is not limited to this. For example, the force application member 19 may also be in contact with the workpiece W adsorbed to the suction pad 12, and in this case too, the force sensor 21 can stably measure a force of a magnitude corresponding to the magnitude of the force applied from the workpiece W to the suction pad 12.

[0028] Furthermore, the higher the rigidity of the force application member 19 and the base member 14, the more accurately the force sensor 21 can measure the force applied from the workpiece W to the suction pad 12 without delay. Therefore, in this embodiment, a metal base member 14 and a metal force application member 19 are employed.

[0029] The control means 24 is connected to the force sensor 21 and can acquire the measurement value of the force sensor 21 from the force sensor 21. The control means 24 detects the suction state of the workpiece W by the suction pad 12 based on the measurement value of the force sensor 21, and controls the exhaust means 22 and the unit moving means 23 to suck the workpiece W at an appropriate negative pressure within a range in which the sucked workpiece W does not come off the suction pad 12, and move the workpiece W to a predetermined position. Here, the control of the exhaust means 22 means adjusting the degree of exhaust from the internal space 11, etc., and the control of the unit moving means 23 means adjusting the moving speed and direction of the suction unit 10, etc.

[0030] Next, the relationship between the measurement value of the force sensor 21 and the suction of the workpiece W by the suction pad 12 will be described. As shown in FIGS. 1A and 1B, when the surface where the contact portion between the suction pad 12 and the workpiece W exists (hereinafter also referred to as the "suction surface") is defined as the xy plane, the axis perpendicular to the xy plane is defined as the z axis, the diameter of the circle in the suction surface where negative pressure acts on the workpiece W is defined as d, and the pressure in the internal space 11 is defined as P in gauge pressure, the workpiece W to be sucked has the following: F s =Pπd 2 A force of / 4 is applied. s is called the "total adsorption force."

[0031] Even if a force is applied to separate the workpiece W from the suction pad 12, the total suction force will not change unless P changes due to air leakage or the like. On the other hand, the force that the workpiece W actually presses on the suction pad 12 during suction (the force applied from the workpiece W to the suction pad 12) F z is reduced by the generation of a force that tries to separate the workpiece W from the suction pad 12. z is called the "effective adsorption force."

[0032] <For 1-axis force sensor> First, consider the case where the force sensor 21 is a one-axis force sensor that measures only the magnitude of the force in the z-axis direction. As shown in Figure 3, the external force acting on the workpiece W (here, gravity acting on the workpiece W is taken as the external force) is expressed as Fe Let it be so. In FIG. 3 (the same applies to FIGS. 4 and 5 described later), the cylindrical object is the suction pad 12, and the object located below the cylindrical object is the work W. The total suction force F acting on the work W s is, F e is in the opposite direction to, and when the work W is adsorbed on the suction pad 12, |F e |<|F s |. In addition to the forces of F s and F e , a force (denoted as F r ) by which the suction pad 12 presses the work W acts on the work W. Therefore, these three forces balance each other, and the work W is in a stationary state with respect to the suction pad 12.

[0033] The force F z by which the work W actually presses the suction pad 12 during adsorption is the force received by the suction pad 12 as a reaction to F r , and F z =-F r . If |F e | increases, |F r | decreases accordingly, and |F z | also decreases. When |F e |>|F s |, the work W detaches from the suction pad 12 and falls. This can be interpreted as "the work W fell because an external force greater than the total suction force was applied." On the other hand, when |F e |>|F s |, |F z | = 0. Based on F z , it can be interpreted that "the work W fell because the effective suction force became zero."

[0034] <In the case of a force sensor capable of measuring moments around the x and y axes> Next, consider the case where the force sensor 21 is a sensor capable of measuring moments around the x and y axes. Here, as shown in FIG. 4, F s and F eThe lines of action of the two do not coincide, and the two lines of action are parallel. This corresponds to the case where the workpiece W is adsorbed in the opposite direction to gravity, but the center of gravity of the workpiece W does not coincide with the center of the adsorption surface when viewed from above. In order to express the stationary state of the workpiece W at this time, F s and F e Consider the balance of forces and moments on the plane containing the line of action of the force, i.e., the Z-ξ plane.

[0035] The contact surface between the workpiece W and the suction pad 12 (hereinafter simply referred to as the "contact surface") is represented by two points on the ξ axis in the Z-ξ plane, and F r1 Force and F r2 Assume that the suction pad 12 presses the workpiece W with a force of . If the workpiece W is stationary at this time, the following equations (1) and (2) hold true.

[0036]

number

[0037] Equations (1) and (2) are r1 and F r2 Solving this with the force of (3) and (4) gives the following equations (3) and (4).

[0038]

number

[0039] However, r=d / 2. From equations (3) and (4), unless l is 0, F r1 and F r2 are different. In this case, F r1 and F r2 is the force F in the Z-ξ plane r and moment M r Using the above, it can be rewritten as the following equations (5) and (6).

[0040]

number

[0041] The force with which the sucked workpiece W presses the suction pad 12 is a reaction force to the force with which the suction pad 12 presses the workpiece W, and what is measured by the force sensor 21 is F r reaction force and M r The reaction moment is F z , M x , M y , F r and M r The relationship is expressed by the following equations (7) and (8).

[0042]

number

[0043] where M r The left screw is the positive, but the M x , M y Please note that the sign is implicitly reversed because a right-handed screw is positive. On the contact surface represented by two points on the ξ axis, the force with which the workpiece W pushes the suction pad 12 is F z1 = -F r1 , F z2 = -F r2 is. The work W is min(|F z1 |,|F z2 |) = 0. Therefore, in this case, min(|F z1 |,|F z2 If we treat |) as the effective adhesive force, we can interpret this as "the effective adhesive force became zero, so workpiece W fell," just like in the example shown in Figure 3.

[0044] <For 6-axis force sensors> The forces and moments acting on a rigid body can be expressed exactly using the corresponding forces and moments for the x, y, and z axes. Therefore, a single force sensor 21 can, in principle, detect any state of the adsorbed workpiece W by measuring up to six of these values. Figure 5 shows the forces on the x and y axes and the moment about the z axis, which were not included in the examples shown in Figures 3 and 4. The forces on the x and y axes and the moment about the z axis act within the adsorption surface, and therefore do not affect the direction in which the workpiece W peels off from the adsorption pad 12.

[0045] On the other hand, the forces on the x and y axes and the moment about the z axis have a significant effect on the shear deformation of the annular elastic body 18 (suction pad 12). Since the shear deformation of the annular elastic body 18 causes the suction state to be released, the workpiece W can actually be released from the suction pad 12 only by the forces on the x and y axes and the moment about the z axis. Therefore, for example, threshold values ​​can be set for the values ​​of the forces on the x and y axes and the moment about the z axis, and when the corresponding threshold values ​​are reached, it can be detected that the workpiece W has been released from the suction pad 12.

[0046] Furthermore, as shown in Figure 2 (B), by using a motion detection means 31 that can detect the inertial motion (changes in posture and movement) of the suction unit 10, a pressure adjustment means 32 that can adjust the pressure in the internal space 11 by human operation, and a memory means 33 that stores time series data on the measurement values ​​of the force sensor 21, the detection values ​​of the motion detection means 31, and the pressure adjustment by the pressure adjustment means 32 together with the suction unit 10, it is possible to teach the robot main body 13, to which the suction unit 10 is attached and which controls the movement and suction process of the suction unit 10, how to suction and move the workpiece W with the suction unit 10 (i.e., the robot main body 13 can be taught).

[0047] The teaching method for the robot body 13 is as follows. First, a person holds the suction unit 10 by hand when it is not attached to the robot body 13. Next, the person operates the pressure adjustment means 32 to create a negative pressure in the internal space 11 and adsorb the workpiece W onto the suction pad 12. Thereafter, while moving the suction unit 10 adsorbing the workpiece W, the measurement values ​​of the force sensor 21, the detection values ​​of the inertial motion of the suction unit 10 by the motion detection means 31, and the pressure adjustment by the pressure adjustment means 32 are continuously or intermittently acquired and stored in the memory means 33.

[0048] In other words, the suction unit 10 not attached to the robot body 13 is held by hand, and the pressure adjustment means 32 for adjusting the pressure in the internal space 11 is operated to create a negative pressure in the internal space 11, the workpiece W is adsorbed onto the suction pad 12, and the suction unit 10 is moved.The measurement value of the force sensor 21, the detection value of the inertial motion of the suction unit 10 by the motion detection means 31, and the time series data of the pressure adjustment by the pressure adjustment means 32 are stored in the memory means 33.

[0049] Next, the time series data of the measured values ​​of the force sensor 21, the detected values ​​of the motion detection means 31, and the pressure adjustment by the pressure adjustment means 32, which are recorded in the storage means 33, are given to the robot body 13 by data transfer or the like. The robot body 13 can reproduce the processing of the workpiece W that a human has performed on the suction unit 10 by controlling the suction unit 10 attached to the robot body 13 in accordance with time series data such as measurement values ​​and detection values ​​stored in the memory means 33.

[0050] An inertial measurement unit (IMU), a positioning system (UWB), or the like can be used as the motion detection means 31. The pressure adjustment means 32 can be configured by, for example, a valve or the like that can adjust the amount of exhaust from the internal space 11. 2(B), a data generating and saving device 30 including a movement detecting means 31, a pressure adjusting means 32, and a memory means 33 can be used for the teaching method of the robot body 13. The movement detecting means 31 can create and save data for the robot body 13 that can be used by the robot body 13 to control the movement of the suction unit 10 and the suction process. [Example]

[0051] Next, an experiment conducted to confirm the effects of the present invention will be described. When a suction unit having the same structure as the embodiment described above is used to pick up a workpiece on a table and when the suctioned workpiece is lifted, the force sensor measurement value (F z ) was investigated. A 6-axis force sensor was used. The workpiece was a rectangular metal plate with a long side of 142 mm and a short side of 125 mm, and a mass of 50 g.

[0052] Fig. 6 shows the measurement results when the suction unit is not holding a workpiece, and then the suction unit picks up a workpiece on the table, and the suction state of the workpiece is maintained for several seconds without lifting it from the table. In the measurement results shown in FIG. 6, the timing when the measurement value (vertical axis) dropped around 1.3 seconds was the time when the suction unit started to suction the workpiece.

[0053] The measurement results when the workpiece picked up by the suction unit was lifted from the table at the same time as the suction unit was lifted are shown in Fig. 7. In the measurement results shown in Fig. 7, the timing when the measurement value started to rise around 1.5 seconds was when the workpiece started to be lifted.

[0054] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions that do not depart from the gist of the present invention are within the scope of application of the present invention. For example, the force applied from the workpiece to the suction pad may be transmitted to the force applying member via a member other than the suction pad. Also, the force applying member does not have to be plate-shaped.

[0055] The force sensor does not have to be in contact with either or both of the suction pad and the force applying member, and the force applying member does not have to be in contact with the force sensor when the suction pad is not sucking a workpiece. Furthermore, the force applied from the workpiece to the suction pad may be transmitted to the force sensor via a member other than the force applying member attached to the suction pad (a member not attached to the suction pad). [Explanation of symbols]

[0056] 10: suction unit, 11: inner space, 12: suction pad, 13: robot body, 14: base member, 15: suction tube, 16: through-hole, 17: annular elastic body, 18: annular elastic body, 19: force application member, 20: through-hole, 21: force sensor, 22: exhaust means, 23: unit movement means, 24: control means, 30: data generation and storage device, 31: motion detection means, 32: pressure adjustment means, 33: memory means, W: work

Claims

1. A suction unit having a suction pad that suctions a workpiece by creating a negative pressure in the inner space, A suction unit characterized by comprising a force sensor that measures the magnitude of a force corresponding to the magnitude of an effective suction force, which is the force with which the suction pad suctions the workpiece minus the force with which the workpiece tries to separate from the suction pad.

2. 2. The suction unit according to claim 1, wherein the force sensor is provided in the inner space.

3. 3. The suction unit according to claim 1, wherein a force applying member is attached to the suction pad, and the force applying member transmits a force applied to the suction pad from the workpiece sucked onto the suction pad to the force sensor.

4. 4. The suction unit according to claim 3, wherein the force-applying member is a plate-like member whose outer edge is supported by the suction pad along its entire periphery, and wherein an inner region of the outer edge disposed in the inner space portion is formed with a through-hole through which air can pass.

5. 3. The suction unit according to claim 1, wherein the force sensor is a six-axis force sensor.

6. a data generating and storing device equipped with a suction unit having a suction pad that suctions a workpiece when a negative pressure is created in an inner space thereof, and a force sensor that measures a magnitude of force corresponding to a magnitude of an effective suction force obtained by subtracting a force with which the workpiece tries to separate from the suction pad from a force with which the suction pad suctions the workpiece, and the device generates and stores data that can be used to control the movement and suction process of the suction unit for a unit control device that controls the movement and suction process of the suction unit, a motion detection means for detecting an inertial motion of the suction unit when the suction unit is not attached to the unit control device; a pressure adjusting means for adjusting the pressure of the internal space; a storage means for storing time-series data of the measured values ​​of the force sensor, the detected values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means;

7. A teaching method is provided in which a suction unit is attached, the suction unit having a suction pad that suctions a workpiece when a negative pressure is created in an inner space thereof, and a force sensor that measures a magnitude of force corresponding to a magnitude of an effective suction force obtained by subtracting a force with which the workpiece tries to separate from the suction pad from a force with which the suction pad suctions the workpiece, and the teaching method instructs a unit control device that controls the movement and suction process of the suction unit how to suction and move the workpiece using the suction unit, a step of holding the suction unit in a state where it is not attached to the unit control device by hand, operating a pressure adjustment means that adjusts the pressure in the internal space to create a negative pressure in the internal space, suctioning the workpiece onto the suction pad, and storing in a storage means time-series data of the measurement values ​​of the force sensor, the detection values ​​of the inertial motion of the suction unit by the motion detection means, and the pressure adjustment by the pressure adjustment means when the suction unit is moved; and providing the unit control device with time series data of the measurement values ​​of the force sensor, the detection values ​​of the motion detection means, and the pressure adjustment by the pressure adjustment means, which are stored in the memory means.

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