阅读说明：本技术 测定零件的重量的重量测定系统以及方法 (Weight measuring system and method for measuring weight of part ) 是由 平雄二 于 2018-05-18 设计创作，主要内容包括：本发明提供能够把持多个零件并测定该多个零件各自的重量的重量测定系统。重量测定系统具备机器人臂部、安装于机器人臂部的重量测定器、安装于重量测定器的多个手部移动机构、通过多个手部移动机构各自的动作而分别移动的多个手部；以及控制部,其控制上述机器人臂部、上述重量测定器、上述多个手部移动机构、以及上述多个手部的动作,上述控制部执行第一重量测定动作、零件把持动作、合计重量测定动作、第二重量测定动作、判定动作、执行不合格品处理动作,在上述不合格品处理动作之后,在上述第一手部把持着上述第一零件的状态下,对下一个第二零件执行上述零件把持动作、上述合计重量测定动作、上述第二重量测定动作、以及上述判定动作。(The invention provides a weight measuring system capable of holding a plurality of parts and measuring the weight of each of the plurality of parts. The weight measuring system comprises a robot arm part, a weight measuring device mounted on the robot arm part, a plurality of hand moving mechanisms mounted on the weight measuring device, and a plurality of hands moved by the respective actions of the plurality of hand moving mechanisms; and a control unit that controls the robot arm, the weight measuring device, the plurality of hand moving mechanisms, and the plurality of hands, wherein the control unit executes a first weight measuring operation, a part gripping operation, a total weight measuring operation, a second weight measuring operation, a determination operation, and a defective product processing operation, and executes the part gripping operation, the total weight measuring operation, the second weight measuring operation, and the determination operation on a second component that is next to the first component in a state where the first component is gripped by the first hand after the defective product processing operation.)

1. A weight measurement system that grips a plurality of components and measures weights of the plurality of components, the weight measurement system comprising:

a robot arm portion;

a weight measuring device attached to the robot arm;

a plurality of hand moving mechanisms attached to the weight measuring instrument;

a plurality of hands which move by the respective operations of the plurality of hand moving mechanisms; and

a control unit for controlling the operation of the robot arm unit, the weight measuring unit, the plurality of hand moving mechanisms, and the plurality of hands,

the control unit performs a first weight measurement operation: the weight measuring device measures the weight of the first component held by the first hand grip by the operation of the first hand moving mechanism,

executing a part holding action: a second hand for holding a second component by operation of a second hand moving mechanism in a state where a first hand holds the first component,

performing a total weight measurement operation: the weight measuring device measures the total weight of the first component held by the first hand and the second component held by the second hand,

performing a second gravimetric determination action: measuring the weight of the second component by subtracting the weight of the first component measured by the first weight measuring operation from the total weight measured by the total weight measuring operation,

and executing a judging action: determining whether the weight of the second component measured by the second weight measuring operation is within a predetermined allowable range,

and executing unqualified product processing action: when it is determined by the determining operation that the weight of the second component is outside the allowable range, the robot arm is operated to move the second component held by the second hand to a predetermined position, the second component is released from the second hand, and the second component is stored in the predetermined position,

after the defective processing operation, the part holding operation, the total weight measuring operation, the second weight measuring operation, and the determining operation are performed on the next second part while the first part is held by the first hand.

2. The weight determination system of claim 1,

the control unit causes the weight measuring device to measure the weight of the first component after a predetermined time has elapsed from the end of the operation of the first hand moving mechanism in the first weight measuring operation.

3. The weight determination system according to claim 1 or 2,

the control unit executes the total weight measuring operation after a predetermined time has elapsed from the end of the component holding operation.

4. The weight measuring system according to any one of claims 1 to 3,

the first hand moving mechanism has a first cylinder, and the second hand moving mechanism has a second cylinder.

5. The weight measuring system according to any one of claims 1 to 4,

the first hand and the second hand each have an adsorption surface capable of adsorbing a component.

6. A method of measuring a weight of a component by using a weight measuring system including a robot arm, a weight measuring instrument attached to the robot arm, a plurality of hand moving mechanisms attached to the weight measuring instrument, and a plurality of hands moved by respective operations of the plurality of hand moving mechanisms, the method being characterized in that,

performing a first gravimetric act: the weight measuring device measures the weight of the first component held by the first hand grip by the operation of the first hand moving mechanism,

executing a part holding action: a second hand for holding a second component by operation of a second hand moving mechanism in a state where a first hand holds the first component,

performing a total weight measurement operation: the weight measuring device measures the total weight of the first component held by the first hand and the second component held by the second hand,

performing a second gravimetric determination action: measuring the weight of the second component by subtracting the weight of the first component measured by the first weight measuring operation from the total weight measured by the total weight measuring operation,

and executing a judging action: determining whether the weight of the second component measured by the second weight measuring operation is within a predetermined allowable range,

and executing unqualified product processing action: when it is determined by the determining operation that the weight of the second component is outside the allowable range, the robot arm is operated to move the second component held by the second hand to a predetermined position, the second component is released from the second hand, and the second component is stored in the predetermined position,

after the defective processing operation, the part holding operation, the total weight measuring operation, the second weight measuring operation, and the determining operation are performed on the next second part while the first part is held by the first hand.

Technical Field

The present invention relates to a weight measuring system and method for measuring the weight of a part.

Background

There is known a weight measurement system for gripping a component and measuring the weight of the component (for example, japanese patent laid-open nos. h 08-094424 and 2016-156707). Today, there is a need for the following technologies: a plurality of parts are gripped and the weights of the plurality of parts are measured.

Disclosure of Invention

In one aspect, the present invention provides a weight measurement system for gripping a plurality of components and measuring weights of the plurality of components, including: a robot arm portion; a weight measuring device attached to the robot arm; a plurality of hand moving mechanisms attached to the weight measuring instrument; a plurality of hands which move by the respective operations of the plurality of hand moving mechanisms; and a control unit that controls operations of the robot arm, the weight measuring device, the plurality of hand moving mechanisms, and the plurality of hands, wherein the control unit performs a first weight measuring operation: causing the weight measuring device to measure the weight of the first component held by the first hand grip by the operation of the first hand moving mechanism, and executing a component holding operation: and a second hand moving mechanism for moving the second hand to hold the second component in a state where the first hand holds the first component, and performing a total weight measuring operation of: causing the weight measuring device to measure a total weight of the first part held by the first hand and the second part held by the second hand, and to perform a second weight measuring operation: determining the weight of the second component by subtracting the weight of the first component measured by the first weight measuring operation from the total weight measured by the total weight measuring operation, and performing a determining operation: determining whether the weight of the second part measured by the second weight measuring operation is within a predetermined allowable range, and executing a defective product processing operation: when it is determined by the determining operation that the weight of the second component is outside the allowable range, the robot arm is operated to move the second component held by the second hand to a predetermined position, the second component is released from the second hand, and the second component is stored in the predetermined position,

after the defective processing operation, the part holding operation, the total weight measuring operation, the second weight measuring operation, and the determining operation are performed on the next second part in a state where the first hand holds the first part.

The method for measuring the mass of a part using the above-described weight measurement system is characterized by performing a first weight measurement operation: causing the weight measuring device to measure the weight of the first component held by the first hand grip by the operation of the first hand moving mechanism, and executing a component holding operation: and a second hand moving mechanism for moving the second hand to hold the second component in a state where the first hand holds the first component, and performing a total weight measuring operation of: causing the weight measuring device to measure a total weight of the first part held by the first hand and the second part held by the second hand, and to perform a second weight measuring operation: determining the weight of the second component by subtracting the weight of the first component measured by the first weight measuring operation from the total weight measured by the total weight measuring operation, and performing a determining operation: determining whether the weight of the second part measured by the second weight measuring operation is within a predetermined allowable range, and executing a defective product processing operation: when it is determined by the determining operation that the weight of the second component is outside the allowable range, the robot arm is operated to move the second component gripped by the second hand to a predetermined position, the second component is released from the second hand, the second component is stored in the predetermined position, and after the defective product handling operation, the component gripping operation, the total weight measuring operation, the second weight measuring operation, and the determining operation are performed on the next second component in a state where the first hand grips the first component.

According to one embodiment of the present disclosure, when the component sorting device is applied to an application for sorting components according to weight, the component sorting operation can be performed more quickly.

Drawings

The objects, features and advantages of the present invention will become further apparent from the following description of the embodiments with reference to the accompanying drawings.

Fig. 1 is a diagram of a weight measuring system according to an embodiment.

Fig. 2 is an enlarged perspective view of the weight measuring instrument and the end effector shown in fig. 1.

Fig. 3 shows a state in which the first hand holds the first component in the end effector shown in fig. 2.

Fig. 4 shows a state in which the first and second hand portions hold the first and second parts, respectively, in the end effector shown in fig. 2.

Fig. 5 is a diagram of a weight measuring system according to another embodiment.

Fig. 6 is a flowchart showing an example of the operation flow of the weight measuring system shown in fig. 5.

Fig. 7 is a flowchart showing an example of the flow of step S3 in fig. 6.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the various embodiments described below, the same elements are denoted by the same reference numerals, and redundant description is omitted. In the following description, for convenience of explanation, the left, right, upper, and lower directions in the drawings will be referred to as the left, right, upper, and lower directions, respectively.

A weight measurement system 10 according to an embodiment will be described with reference to fig. 1 to 4. The weight measuring system 10 is used for measuring the weight of a vehicleHolding part A described later₁And A₂(FIGS. 3 and 4) and the above-mentioned part A was measured₁And A₂The weight of (c).

As shown in fig. 1, the weight measurement system 10 includes a robot 12, a weight measuring device 14, and an end effector 16. In the present embodiment, the robot 12 is a parallel link robot. Specifically, the robot 12 includes a base portion 18 and a robot arm portion 19.

The robot arm 19 includes a movable portion 20, a first link mechanism 22, a second link mechanism 24, and a third link mechanism 26. The movable portion 20 is movably supported by the base portion 18 via a first link mechanism 22, a second link mechanism 24, and a third link mechanism 26. In the present embodiment, the movable portion 20 is a substantially truncated cone-shaped member having a central axis O.

The first linkage 22 has a first drive link 28 and a pair of follower links 30 and 32. The first drive link 28 is rotatably coupled to the base portion 18. The base end portions of the pair of driven links 30 and 32 are rotatably coupled to the tip end portion of the first drive link 28, and the tip end portions thereof are rotatably coupled to the movable portion 20.

The second link mechanism 24 has the same structure as the first link mechanism 22. Specifically, the second link mechanism 24 includes a second drive link 34 and a pair of follower links 36 and 38 that are rotatably coupled to the base portion 18. The base end portions of the pair of driven links 36 and 38 are rotatably coupled to the tip end portion of the second drive link 34, and the tip end portions thereof are rotatably coupled to the movable portion 20.

The third link mechanism 26 has the same structure as the first link mechanism 22. Specifically, the third link mechanism 26 includes a third drive link (not shown) rotatably coupled to the base portion 18 and a pair of follower links 40 and 42. The base end portions of the pair of driven links 40 and 42 are rotatably coupled to the tip end portion of the third drive link, and the tip end portions thereof are rotatably coupled to the movable portion 20.

The robot arm 19 further includes a first link driving unit (not shown) for rotating the first drive link 28, a second link driving unit (not shown) for rotating the second drive link 34, and a third link driving unit (not shown) for rotating the third drive link.

The first link driving unit, the second link driving unit, and the third link driving unit can move the movable unit 20 in three axial directions of the orthogonal coordinate system by rotating the first driving link 28, the second driving link 34, and the third driving link independently of each other.

The robot arm 19 further has an auxiliary drive unit 44 and an auxiliary shaft 46. In the present embodiment, the auxiliary driving portion 44 is disposed between the driven links 36 and 38. The auxiliary driving portion 44 has a base end portion coupled to the second driving link 34, and a lower end portion slidably coupled to the driven links 36 and 38 via a mounting member 48.

The auxiliary shaft 46 has a base end portion coupled to the auxiliary driving portion 44 and a tip end portion rotatably coupled to the movable portion 20, and extends between the auxiliary driving portion 44 and the movable portion 20 so as to be parallel to the driven links 36 and 38.

The auxiliary driving portion 44 advances and retracts the auxiliary shaft 46 in the extending direction of the driven links 36 and 38. The auxiliary driving unit 44 changes the posture of the movable unit 20 by advancing and retreating the auxiliary shaft 46.

The weight measuring instrument 14 is attached to the distal end portion 20a of the movable portion 20. As shown in fig. 2, the weight measuring device 14 includes a substantially cylindrical case 14a and a sensor element (not shown) incorporated in the case 14 a.

The base end portion 14b of the housing 14a is fixed to the tip end portion 20a of the movable portion 20. In the present embodiment, the weight measuring instrument 14 (specifically, the housing 14a) is disposed concentrically with the movable portion 20 so that the center axis thereof substantially coincides with the center axis O of the movable portion 20.

The sensor element is a strain gauge, a load cell, or the like, and is based on the end effector 16 and the part A held by the end effector 16₁、A₂The force acting on the weight measuring instrument 14 is detected by the weight (fig. 3 and 4). The weight measurement system 10 can measure the weight of the end effector 16 by removing the component generated by the weight of the end effector 16 from the detection value of the sensor elementHolding part A₁、A₂(fig. 3, fig. 4).

The end effector 16 includes a base 50, a first hand 52, a second hand 54, a first hand moving mechanism 56, and a second hand moving mechanism 58. In the present embodiment, the base 50 is fixed to the distal end portion 14c of the weight measuring instrument 14 (specifically, the housing 14 a).

In the present embodiment, the base 50 is a substantially rectangular parallelepiped member, and is disposed concentrically with the movable portion 20 and the weight measuring instrument 14 so that the central axis thereof substantially coincides with the central axis O of the movable portion 20 and the weight measuring instrument 14.

The first hand movement mechanism 56 is disposed between the weight measuring device 14 and the first hand 52, and is attached to the distal end portion 14c of the weight measuring device 14 via the base 50. In the present embodiment, the first hand movement mechanism 56 is an air cylinder, and includes a cylinder main body 56a and a cylinder shaft 56b (fig. 3).

The cylinder body 56a is hollow and fixed to the right side surface 50a of the base 50. The cylinder shaft 56b is housed in the cylinder main body 56a so as to be able to advance and retreat, and extends downward from the cylinder main body 56a along the axis O.

An air supply device (not shown) provided outside the weight measurement system 10 is connected to the cylinder body 56a, and the air supply device increases or decreases the pressure of the cylinder body 56 a. The cylinder shaft 56b advances and retracts along the axis O according to the pressure of the cylinder main body 56 a.

Specifically, when the pressure of the cylinder main body 56a is LOW (LOW), the cylinder shaft 56b is disposed at the retracted position shown in fig. 2, and thus the first hand 52 is also disposed at the retracted position.

When the pressure of the cylinder main body 56a is set High (High) by the air supply device from the state shown in fig. 2, the cylinder shaft 56b is pressed downward, and the cylinder shaft 56b is disposed at the advanced position shown in fig. 3. Thus, the first hand 52 is also disposed at the advanced position. Here, the advanced position is a position farther from the base 50 than the retracted position. Thus, the first hand moving mechanism 56 advances and retreats the first hand 52 along the axis O.

The second hand moving mechanism 58 is disposed between the weight measuring instrument 14 and the second hand 54, and is attached to the distal end portion 14c of the weight measuring instrument 14 via the base 50. The second hand movement mechanism 58 has the same configuration as the first hand movement mechanism 56, and is disposed symmetrically with respect to the first hand movement mechanism 56 with the axis O as a reference.

Specifically, the second hand moving mechanism 58 is an air cylinder, and includes a hollow cylinder main body 58a fixed to the left side surface 50b of the base 50, and a cylinder shaft 58b (fig. 4) accommodated in the cylinder main body 58a so as to be able to advance and retreat and extending along the axis O.

An air supply device (not shown) provided outside is connected to the cylinder main body 58a, and the air supply device increases or decreases the pressure of the cylinder main body 58 a. When the pressure of the cylinder main body 58a is low, the cylinder shaft 58b is disposed at the retracted position shown in fig. 2, and thereby the second hand 54 is also disposed at the retracted position.

When the pressure of the cylinder main body 58a is increased by the air supply device from the state shown in fig. 2, the cylinder shaft 58b is pressed downward, and the cylinder shaft 58b is disposed at the advanced position shown in fig. 4, whereby the second hand 54 is also disposed at the advanced position. Thus, the second hand moving mechanism 58 moves the second hand 54 forward and backward along the axis O.

The first hand 52 is fixed to a distal end portion of a cylinder shaft 56b of the first hand moving mechanism 56. The first hand 52 includes a bracket 60, a negative pressure generator 62, and a suction unit 64.

The bracket 60 is a flat plate-like member, and a left end portion 60a thereof is fixed to a front end portion of the cylinder shaft 56 b. The bracket 60 is disposed to extend and protrude rightward from the cylinder shaft 56 b.

The negative pressure generating device 62 is cylindrical and fixed to the right end portion 60b of the bracket 60 so as to protrude downward from the bracket 60. The suction portion 64 is annular and fixed to the distal end portion 62a of the negative pressure generating device 62.

In the present embodiment, the negative pressure generating device 62 and the suction portion 64 have center axes O that coincide with each other₁And are arranged concentrically with each other. Axis O₁Substantially parallel to the axis O and separated to the right from the axis O.

The interior of the suction portion 64 communicates with the interior of the negative pressure generating device 62. The suction portion 64 has a suction surface 64a at its tip. At least one vent hole (not shown) is formed in the suction surface 64 a.

An air supply device (not shown) provided outside is connected to the negative pressure generating device 62. When the air supply device sends air to the negative pressure generating device 62 and the pressure in the negative pressure generating device 62 is set to High (High), the negative pressure generating device 62 generates a negative pressure inside the suction portion 64.

This generates an air flow flowing into the suction portion 64 from the vent hole forming the suction surface 64a, and the first component a can be attached as shown in fig. 3₁Is adsorbed on the adsorption surface 64 a. Thus, the first hand 52 can hold the first component a₁。

The second hand 54 has the same configuration as the first hand 52, and is disposed symmetrically with respect to the first hand 52 with the axis O as a reference. Specifically, the second hand 54 is fixed to the distal end portion of the cylinder shaft 58b of the second hand moving mechanism 58, and includes a bracket 66, a negative pressure generating device 68, and an adsorbing portion 70.

The bracket 66 is a flat plate-like member, and a right end portion 66a thereof is fixed to a front end portion of the cylinder shaft 58 b. The bracket 66 is disposed to extend and protrude leftward from the cylinder shaft 58 b.

The negative pressure generating device 68 is cylindrical and fixed to the left end portion 66b of the bracket 66 so as to protrude downward from the bracket 66. The suction unit 70 is annular and fixed to the distal end portion 68a of the negative pressure generator 68.

In the present embodiment, the negative pressure generating device 68 and the suction portion 70 have center axes O that coincide with each other₂And are arranged concentrically with each other. Axis O₂Substantially parallel to the axis O and spaced leftward from the axis O.

The interior of the suction portion 70 communicates with the interior of the negative pressure generating device 68. The suction portion 70 has a suction surface 70a at its tip. At least one vent hole (not shown) is formed in the suction surface 70 a.

An air supply device (not shown) is connected to the negative pressure generating device 68. When the air supply device sends air to the negative pressure generating device 68 and the pressure in the negative pressure generating device 68 is set High (High), the negative pressure generating device 68 generates a negative pressure inside the suction portion 70.

Thereby, the vent hole formed in the suction surface 70a is generatedThe second component A can be attached to the air flow flowing into the suction part 70 as shown in FIG. 4₂Is adsorbed on the adsorption surface 70 a. Thus, the second hand 54 can hold the second component A₂. In addition, the first part A₁And a second part A₂Is a food (e.g., snack) or an IC chip.

The weight measuring device 14 measures the first part A₁Weight W of₁And a second part A₂Weight W of₂Wherein the first part A₁The second component A is held by the first hand 52 moved by the operation of the first hand moving mechanism 56₂The second hand 54 moved by the operation of the second hand moving mechanism 58 is gripped. The weight measurement system 10 is configured to measure the weight W separately₁And W₂。

For example, the weight measuring system 10 first holds the first part a with the first hand 52 as shown in fig. 3₁And the first part A is first measured by the weight measuring device 14₁Weight W of₁. Next, as shown in fig. 4, the weight measuring system 10 holds the first component a with the first hand 52₁In the state of (1), the second hand 54 holds the second component A₂And the first part A is measured by the weight measuring device 14₁Weight W of₁With the second part A₂Weight W of₂Total weight W of_S(＝W₁+W₂)。

The weight measuring system 10 measures the total weight W_SMinus the first part A₁Weight W of₁To calculate the second part A₂Weight W of₂. Thus, the weight measuring system 10 can measure the weight W separately₁And weight W₂。

As another example, first, as shown in fig. 4, the weight measuring system 10 grips the first component a by the first hand 52 and the second hand 54, respectively₁And a second part A₂And the first part A is measured by the weight measuring device 14₁Weight W of₁With the second part A₂Weight W of₂Total weight W of_S。

Next, the weight measuring system 10 releases the second part A from the second hand 54₂The first part A is measured by the weight measuring device 14₁Weight W of₁. The weight measuring system 10 measures the total weight W_SMinus the first part A₁Weight W of₁To calculate the second part A₂Weight W of₂. Thus, the weight measuring system 10 can measure the weight W separately₁And weight W₂。

As described above, according to the present embodiment, the plurality of hand portions 52 and 54 can hold the plurality of parts a₁And A₂And can measure the plurality of parts A₁And A₂Each weight W of₁And W₂。

According to this configuration, the weight measuring system 10 is applied to the basis weight W₁、W₂To select part A₁、A₂In such an application, the sorting operation of the parts can be performed more quickly.

In the present embodiment, a case where the end effector 16 includes the two hand units 52 and 54 in total and the two hand moving mechanisms 56 and 58 in total has been described. However, the end effector 16 is not limited to this, and may include a total of n (n is an integer of 3 or more) hands and a total of n hand moving mechanisms. The nth hand moving mechanism moves the nth hand for holding the nth component A_n。

For example, the end effector 16 shown in fig. 2 may further include: a third hand movement mechanism fixed to the front surface (surface on the paper surface side in fig. 2) of the base 50; a third hand moved by the operation of the third hand moving mechanism; a fourth hand moving mechanism fixed to the rear surface (the surface on the back side of the sheet of fig. 2) of the base 50; and a third hand moved by the operation of the fourth hand moving mechanism.

In this case, the third hand moving mechanism and the fourth hand moving mechanism may have the same configurations as the hand moving mechanisms 56 and 58 described above. The third hand and the fourth hand may have the same configurations as the hand 52 and 54 described above.

Next, a weight measurement system 100 according to another embodiment will be described with reference to fig. 5. The weight measurement system 100 is a system for gripping a part a conveyed by a conveyor 108 and measuring the weight of the part a.

The weight measurement system 100 includes a control unit 102, a vision sensor 104, a timer unit 106, the robot 12, a weight measuring device 14, and an end effector 16. The control unit 102 has a CPU and a memory (not shown), and directly or indirectly controls the vision sensor 104, the robot 12, the weight measuring instrument 14, and the end effector 16.

The vision sensor 104 is, for example, a three-dimensional vision sensor, and is disposed vertically above the conveyor 108. The vision sensor 104 captures an image of the part a conveyed by the conveyor 108, and transmits the captured image of the part a to the control unit 102.

The control unit 102 acquires the position and orientation of each component a on the conveyor 108 based on the image of the component a received from the vision sensor 104. The timer unit 106 counts an elapsed time t from a predetermined time point in response to an instruction from the control unit 102.

Next, the operation of the weight measuring system 100 will be described with reference to fig. 6. The flow shown in fig. 6 is started when the control unit 102 receives an operation start instruction from a user or a host controller.

For example, after the start of the operation of the conveyor 108, the user or the host controller transmits an operation start command to the control unit 102. After the operation of the conveyor 108 is started, the component a is continuously placed on the upstream end of the conveyor 108.

In step S1, the control unit 102 sets the number "n" specifying the nth hand movement mechanism and the nth hand to "1". In the present embodiment, n is 1, 2.

In step S2, the control unit 102 starts imaging of the part a by the vision sensor 104. Specifically, the control unit 102 transmits a shooting start instruction to the vision sensor 104. When the vision sensor 104 receives the photographing start command, the part a conveyed by the conveyor 108 is continuously (for example, at a cycle τ) photographed, and the photographed image of the part a is transmitted to the control unit 102. The control unit 102 acquires the position and orientation of each component a based on the image received from the vision sensor 104.

In step S3, the control unit 102 performs measurement of the nth component a_nThe step (2) is a step of (1). Step S3 is explained below with reference to fig. 7.

In step S11, the control unit 102 sets the position of the nth component a among the components a on the conveyor 108 to the component a on the nth position_nThe nth hand is positioned. Specifically, the control unit 102 bases the nth component a out of the components a on the conveyor 108 acquired in step S2_nThe robot 12 is controlled by the position and posture of the component A, and the suction part (64 or 70) of the nth hand (52 or 54) is placed on the nth component A_nFollows the nth component A at an upper position_nThe movable portion 20 is moved.

Assuming that the current time is set to n equal to 1, the control unit 102 bases the first component a on the conveyor 108₁The robot 12 is controlled by the position and posture of the first hand 52, and the suction part 64 of the first hand 52 follows the first component a₁The movable portion 20 is moved.

In step S12, the control unit 102 operates the nth hand movement mechanism (56 or 58) to move the nth hand (52 or 54) to the forward position. Specifically, the control unit 102 sends a command to the air supply device to change the pressure of the cylinder main body (56a or 58a) of the nth hand movement mechanism from low to high.

Thereby, the nth hand moving mechanism moves the nth hand from the backward position to the forward position. If the current time is set to "n" 1, the control unit 102 operates the first hand movement mechanism 56 to move the first hand 52 to the forward position.

After the step S12 is executed, the suction surface of the nth hand is gently brought into contact with the nth part a_nOr adjacently arranged on the n-th part A_nWith respect to the nth part A, the robot 12_nThe movable part 20 is positioned.

In step S13, the control unit 102 uses the nthThe nth component A is held by a hand_n. Specifically, the control unit 102 sends a command to the air supply device to send air to the negative pressure generating device (62 or 68) of the nth hand (52 or 54).

Thus, the negative pressure generating device generates negative pressure inside the suction part (64 or 70), and as a result, the nth component A_nIs adsorbed on the adsorption surface (64a or 70 a). Assuming that n is 1 at the current time, the control unit 102 operates the negative pressure generating device 62 of the first hand 52 to operate the first component a₁Is adsorbed by the adsorption part 64.

In step S14, the control unit 102 determines whether or not the nth hand has properly gripped the nth component a_n. For example, the control unit 102 monitors the pressure in the negative pressure generating devices (62, 68) of the nth hands (52, 54), and determines that the nth component a is a component that fluctuates beyond a predetermined threshold value_nIs appropriately adsorbed on the adsorption surfaces (64a, 70a) of the nth hands (52, 54) and is held.

As another example, the control unit 102 monitors the weight detected by the weight measuring instrument 14, and determines that the nth component a is an nth component when the weight increases beyond a predetermined threshold value_nIs appropriately adsorbed on the adsorption surfaces (64a, 70a) of the nth hands (52, 54) and is held.

The control unit 102 determines that the nth hand has properly gripped the nth component a_nIf yes, the process proceeds to step S15. On the other hand, the control unit 102 determines that the nth hand does not properly grip the nth component a_n(i.e., no), the loop goes to step S14.

In step S15, the control unit 102 operates the nth hand movement mechanism to move the nth hand to the backward position. Specifically, the control unit 102 sends a command to the air supply device to change the pressure of the cylinder main body (56a or 58a) of the nth hand movement mechanism (56 or 58) from high to low. Thus, the nth hand moving mechanism moves the nth hand (52 or 54) from the advanced position to the retracted position.

Assume that in the case where the current time is set to n-1, controlThe unit 102 moves the first hand moving mechanism 56 to move the first hand 52 to the backward position. As a result, the first hand 52 holds the first component a at a position separated upward from the conveyor 108₁。

On the other hand, if the current time is set to "n" 2 (that is, if step S3 is executed for the second time), the control unit 102 operates the second hand moving mechanism 58 to move the second hand 54 to the retracted position. As a result, the first component a is held by the first hand 52₁In the state (2), the second hand 54 holds the second component A at a position separated upward from the conveyor 108₂。

In step S16, control unit 102 starts counting elapsed time t by timer unit 106. Specifically, the control unit 102 sends a timing command to the timing unit 106. The timer unit 106 counts the elapsed time t from the time when the controller 102 receives the timing command.

For example, the control unit 102 determines whether or not the operation of the nth hand movement mechanism (56, 58) is finished in step S15, and transmits a timer command to the timer unit 106 when it is determined that the operation of the nth hand movement mechanism is finished.

In this case, the nth hand moving mechanism may include a non-contact sensor (not shown) provided at a base end (corresponding to the retreating position) of the movement stroke of the cylinder shafts (56b, 58b), and the non-contact sensor may detect that the cylinder shafts (56b, 58b) have moved to the retreating position. When the noncontact sensor detects that the cylinder shafts (56b, 58b) have moved to the retracted position, the control unit 102 determines that the operation of the nth hand movement mechanism has been completed, and sends a timer command to the timer unit 106.

As another example, controller 102 may transmit a timer command to timer unit 106 after a predetermined time has elapsed from the start time of step S15 (specifically, the time at which controller 102 transmits a command to the air supply device in step S15). The predetermined time is determined to be sufficient time for the operation of the nth hand movement mechanism to be completed in step S15.

In step S17, control unit 102 determinesWhether or not a predetermined time has elapsed from the start time of step S16. Specifically, the control unit 102 determines whether or not the elapsed time t measured by the time measuring unit 106 has reached a predetermined time t_R. The time t_RPredetermined by the user and stored in the memory of the control unit 102.

When determining that the elapsed time t measured by the time measuring unit 106 has reached the time t, the control unit 102_RIf yes, the process proceeds to step S18. On the other hand, the control unit 102 determines that the elapsed time t measured by the time measuring unit 106 has not reached the time t_R(i.e., no), the loop goes to step S17.

If yes is determined in step S17, the movement of the nth hand (52 or 54) is completely completed and the nth hand is in a stationary state. In other words, the above time t_RThe time period required for the nth hand to be stationary after step S15 is executed can be set as a sufficient time period.

In step S18, the control unit 102 measures the weight W of the part a held by the end effector 16. Specifically, the control unit 102 sends a command to the weight measuring device 14, and the weight measuring device 14 measures the weight W of the part a held by the end effector 16.

It is assumed that in the case where step S18 is performed when n is set to 1, since the end effector 16 holds only the first part a as shown in fig. 3₁Therefore, in step S18, the weight W measured by the weight measuring instrument 14 is the component A₁Weight W of₁。

On the other hand, when step S18 is executed when n is set to 2, the end effector 16 grips the component a as shown in fig. 4₁And A₂. Therefore, the weight W measured by the weight measuring device 14 in step S18 is the first part a₁Weight W of₁With the second part A₂Weight W of₂Total weight W of_S. Total weight W_SRepresented by the following formula 1.

In step S19, the control unit 102 determines whether the number "n" is set to "1". If it is determined that n is 1 (i.e., yes), the control unit 102 proceeds to step S20. On the other hand, when determining that the number "n" is not set to "1" (i.e., no), the control unit 102 proceeds to step S23.

In step S20, the control unit 102 measures the first part a₁Weight W of₁. Specifically, the control unit 102 acquires the weight W measured in the latest step S18 as the first component a₁Weight W of₁。

On the other hand, if it is determined no in step S19, the controller 102 measures the total weight W of the weights W of the parts a held by the end effector 16 in step S23_S. Specifically, the control unit 102 acquires the weight W measured in the last step S18 as the total weight W_S。

In step S24, the control unit 102 measures the nth component a_nWeight W of_n. Specifically, the control unit 102 passes the total weight W calculated in the last step S23_SSubtracting each part A obtained up to the present time₁～A_n－1Total weight W of_S－1To determine the nth part A_nWeight W of_n. Here, the total weight W_S－1Represented by the following formula.

Assuming that n is 2 at the current time, the control unit 102 passes the total weight W measured in step S23_S(＝W₁+W₂) Subtracting the first part A measured in step S20₁Weight W of₁To measure the second part A₂Weight W of₂. In this way, in the present embodiment, the control unit 102 sets the second component a₂Weight W of₂As the total weight W_SWith the first part A₁Weight W of₁Difference of (W)_S－W₁) And (4) carrying out measurement.

In step S21, control unit 102 determines weight W obtained in step S20 or S24_nWhether it is within a predetermined allowable range [ alpha, beta ]]And (4) the following steps. The allowable range [ alpha, beta ]]Predetermined by the user and stored in the memory of the control unit 102. The control part 102 is at weight W_nWithin the allowable range (i.e., α ≦ W_nβ), the determination is yes, and the routine proceeds to step S4 in fig. 6.

On the other hand, the control unit 102 is set at the weight W_nOutside of a predetermined allowable range (i.e., W)_n< alpha or beta < W_n) If no, the process proceeds to step S22. The allowable range [ alpha, beta ]]The weight of the component a is determined to be appropriate, and the component a having a weight outside the allowable range is sorted as a defective product (step S22 described later).

In step S22, control unit 102 sets forth nth component a determined as no in step S21_nAnd transporting the blank to a predetermined defective product storage place. The defective product storage location is a location for storing the component a of the defective product.

The control unit 102 operates the robot 12 to determine the nth component a determined as no in step S21_nAnd transporting the blank to the upper part of the unqualified product storage place. Then, a command is sent to the air supply device to release air from the negative pressure generating devices (62, 68) of the nth hands (52, 54). As a result, the negative pressure generated by the negative pressure generating devices (62, 68) is eliminated, and the nth component A_nIs released from the adsorption surfaces (64a, 70a) and is stored in a defective product storage place.

Referring again to fig. 6, in step S4, control unit 102 increments number "n" by 1 (i.e., n equals n + 1). Assuming that when the current time is set to "n" 1, the control unit 102 increases the number "n" from "1" to "2".

In step S5, the control unit 102 determines whether or not the number "n" is a value larger than γ. The value γ is set to be the same as the number of hands 52 and 54 (i.e., hand movement mechanisms 56 and 58). In the present embodiment, the number of the hands 52 and 54 (i.e., the hand moving mechanisms 56 and 58) is 2, and γ is set to 2.

If it is determined that n > γ (i.e., yes), the control unit 102 proceeds to step S6. On the other hand, when determining that n is not more than γ (i.e., no), the control unit 102 returns to step S3. In this way, the controller 102 loops through steps S3 to S5 until the determination of step S5 is yes.

In step S6, the control unit 102 sets the part a (i.e., the part a) held by the end effector 16₁And A₂) And transporting the product to a predetermined qualified product storage place. The non-defective product storage place is a place for storing the non-defective component a.

The control unit 102 operates the robot 12 to hold the part A held by the end effector 16₁And A₂And transporting the qualified product to the upper part of a qualified product storage place. Then, a command is sent to the air supply device to release air from the negative pressure generation devices 62 and 68 of all the hands 52 and 54. Thus, the negative pressure generated by the negative pressure generating devices 62 and 68 disappears, and the component a₁And A₂Are released from the suction surfaces 64a and 70a and stored in a non-defective product storage place.

In step S7, the control unit 102 determines whether or not an operation end command has been received from the user or the upper controller. If it is determined that the operation end command has been received (i.e., yes), control unit 102 ends the flow shown in fig. 6. On the other hand, if it is determined that the operation end command has not been received (i.e., no), the control unit 102 returns to step S1.

As described above, in the present embodiment, the control unit 102 grips the plurality of parts a by the end effector 16₁And A₂(step S13), these parts A can be measured₁And A₂Each weight W₁And W₂(steps S20, S24). With this configuration, the operation of determining the acceptability or non-acceptability of the component a based on the weight W can be efficiently performed in the production line.

In the present embodiment, the control unit 102 acquires the total weight W of the weights of the plurality of components a held by the end effector 16_s(step S23) by calculating the total weight W_sMinus the total weight W_sThe steps performed before the acquisitionPart A calculated in steps S20 and S24₁～A_n－1Total weight W of_S－1To calculate the nth part A_nWeight W of_n(step S24). With this configuration, the plurality of components a held by the end effector 16 can be measured quickly and accurately by a relatively simple algorithm₁～A_nEach weight W₁～W_n。

In the present embodiment, after the operation of the nth hand movement mechanism (56 or 58) is ended in step S15, a predetermined time t has elapsed_RIf yes at step S17, controller 102 measures the weight W of component a (step S18). With this configuration, the weight W of the component a can be measured when the nth hand is completely stationary after the execution of step S15, and thus the weight W can be measured with higher accuracy.

In the present embodiment, the first hand moving mechanism 56 and the second hand moving mechanism 58 are air cylinders, respectively. With this configuration, the first hand moving mechanism 56 and the second hand moving mechanism 58 can be made lightweight, and the inertia of the end effector 16 can be reduced.

In the present embodiment, the controller 102 conveys the component a having a weight outside the allowable range to the defective product storage location (step S22), and conveys the component a having a weight within the allowable range to the defective product storage location (step S6). With this configuration, the component a can be sorted into a good product and a bad product, and stored in different places.

Even when the end effector 16 includes a total of n (n is an integer of 3 or more) hands and a total of n hand movement mechanisms, the control unit 102 executes the flow shown in fig. 6 and 7 to sequentially grip the component a by the end effector 16₁～A_nIt is also possible to measure these parts A₁～A_nWeight W of₁～W_nThe respective weight of (c).

In the above-described embodiment, the case where the hands 52 and 54 have the negative pressure generating devices 62 and 68 has been described. However, the hand 52 or 54 may be provided with a hollow member instead of the negative pressure generating device 62 or 68.

In this case, an air suction device provided outside the weight measurement system 100 may be connected to the hollow member, and the air suction device may reduce the air pressure inside the hollow member to generate a negative pressure inside the suction portion 64 or 70.

The first hand 52 or 54 may have an electromagnet, a suction cup, an adhesive material, or the like instead of the negative pressure generating device 62 or 68 and the suction portion 64 or 70, and may grip the component a by these elements. Alternatively, the first hand 52 or 54 may have a plurality of openable and closable finger portions, and the component a may be gripped by the finger portions.

In the above-described embodiment, the case where the hand moving mechanisms 56 and 58 are air cylinders has been described. However, the hand moving mechanisms 56 and 58 are not limited to this, and may be, for example, servo motors, linear motors, or any other devices that can move the hands 52 and 54.

In the above-described embodiment, the case where the robot 12 is a parallel link robot is described. However, the robot 12 is not limited to this, and may be a vertical articulated robot, for example. In this case, the proximal end portion 14b of the weight measuring instrument 14 may be provided at the distal end portion of the wrist portion of the vertical articulated robot. Alternatively, the robot 12 may be a robot such as a loader.

The present disclosure has been described above by way of embodiments, but the embodiments described above do not limit the invention of the claims.