JP2012152843A - Sucking device and robot system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sucking device and a robot system that can detect wear of a suction pad.SOLUTION: The robot system 10 includes: a robot 20 having end effectors 48a and 48b on which the suction pad 76 for sucking an article G to be carried and pressure sensors 66a-66d for detecting suction pressure of the suction pad 76 are provided; and a control device 30 having a determination part 86 for determining the wear of the suction pad 76 based on transition data D of the suction pressure detected by the pressure sensors 66a-66d during a period since the suction pad 76 sucks the article G until the suction pressure of the suction pad 76 gets stable.

Description

  The present invention relates to a suction device and a robot system.

Patent Document 1 describes a transfer robot. The transfer robot includes at least a hand unit for placing a transported object, a second arm that rotatably supports the hand unit, and a first arm that rotatably supports the second arm. A horizontal arm mechanism in which the arm rotates to move in the direction, and an elevating mechanism for moving the horizontal arm mechanism up and down.
In some cases, the hand portion of the transfer robot is provided with a suction pad for air suction of the conveyed product.

Japanese Patent No. 4466785

Here, in general, the suction pad is worn according to the frequency of use. This suction pad wear is discovered only when the transported object sucked on the suction pad is displaced.
An object of this invention is to provide the adsorption | suction apparatus and robot system which can detect abrasion of an adsorption pad.

A robot system according to a first aspect of the present invention that meets the above-described object includes a robot having a suction pad that sucks a conveyed product and an end effector provided with a pressure sensor that detects a suction pressure of the suction pad;
The suction pad is based on transient data of the suction pressure detected by the pressure sensor from when the suction pad sucks the transported object until the transported object sucked by the suction pad starts moving. And a control device having a determination unit for determining the wear of the.

  In the robot system according to the first invention, the determination unit determines in advance the time necessary for the suction pressure of the suction pad to change from the first magnitude to the second magnitude based on the transient data. The first alarm can be output when it is determined that the first condition, which is that the predetermined time has been exceeded, is satisfied.

In the robot system according to the first invention, the first magnitude is a magnitude of the suction pressure when the suction pad sucks the conveyed object,
The second magnitude can be the magnitude of the suction pressure when the transported object sucked by the suction pad starts moving.

In the robot system according to the first aspect of the present invention, the determination unit is configured to wait until the suction pressure of the suction pad is stabilized after the suction pad sucks the conveyed object when the suction pad is not worn. The reference transient data corresponding to the transient data acquired from the pressure sensor and the degree of mismatch between the transient data are obtained,
A second alarm can be output when it is determined that the second condition that the degree of mismatch exceeds a predetermined size is satisfied.

In the robot system according to the first invention, the determination unit obtains a degree of inconsistency between the transient data and correlation data correlated with the transient data,
A third alarm can be output when it is determined that the third condition that the degree of inconsistency exceeds a predetermined size is satisfied.

  In the robot system according to the first invention, it is preferable that the correlation data is moving average data of the transient data.

  In the robot system according to the first invention, the determination unit counts the number of outputs each time one of the first to third alarms is output, and sets the number of outputs to a predetermined value. A fourth alarm can be output when it is determined that the fourth condition, which is exceeded, is satisfied.

In the robot system according to the first invention, the suction pad is provided for each pressure piping system for controlling the suction pressure of the suction pad,
The pressure sensor is preferably provided in each pressure piping system.

In the robot system according to the first invention, the end effector converts an analog signal output from each pressure sensor into a digital signal and outputs the digital signal;
A parallel / serial converter that converts the output of the A / D converter from a parallel signal into a serial signal and outputs the serial signal;
A transmitter for transmitting a serial signal output from the parallel / serial converter;
The control device preferably includes a receiver that receives the serial signal transmitted by the transmitter.

In the robot system according to the first invention, the end effector includes a frame and a fork member extending from the frame,
The A / D converter, the parallel / serial converter, and the transmitter are provided in the frame;
It is preferable that the suction pad is provided on the fork member.

A suction device according to a second invention that meets the above-described object is a suction pad that sucks an article;
A pressure sensor for detecting the suction pressure of the suction pad;
A determination unit that determines wear of the suction pad based on transient data of the suction pressure detected by the pressure sensor from when the suction pad sucks the article to when the suction pressure of the suction pad becomes stable. With.

  In the suction device and the robot system according to the present invention, it is possible to detect the wear of the suction pad.

It is a rear view of the robot which the robot system concerning one embodiment of the present invention has. It is a right view of the robot which the robot system has. It is a top view of the end effector of the robot which the robot system has. It is a Y direction arrow line view of FIG. It is a pressure piping system diagram of the suction pad provided in the end effector of the robot which the robot system has. It is explanatory drawing which shows the structure for transmitting the pressure signal of the suction pad of the robot which the robot system has. It is a functional block diagram of the robot system. It is a flowchart which shows the operation | movement in which the robot system detects wear of a suction pad. It is a graph which shows the transient data memorize | stored in the data storage part of the control apparatus which the robot system has. It is a graph which shows the standard transient data memorized by the standard data storage part of the control device which the robot system has. It is a graph which shows the data of the moving average of the transient data memorize | stored in the data storage part of the control apparatus which the robot system has.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In each drawing, portions not related to the description may be omitted.

As shown in FIG. 1, a robot system 10 according to an embodiment of the present invention includes a substrate transfer robot (an example of a robot) 20 and a control device 30 that controls the operation of the substrate transfer robot 20.
The substrate transfer robot 20 includes a traveling mechanism 42, an elevating mechanism 44, and first and second arm portions 46a and 46b, and is provided at first ends of the first and second arm portions 46a and 46b, respectively. The liquid crystal glass substrate G (an example of a conveyed product and an article) shown in FIG. 3 can be conveyed using the first and second end effectors 48a and 48b.
The traveling mechanism 42 can move the elevating mechanism 44 in the traveling direction (see the arrow shown in FIG. 1) that intersects the transport direction of the liquid crystal glass substrate G.
The elevating mechanism 44 can turn around an axis S <b> 1 that intersects the installation surface of the substrate transport robot 20. The elevating mechanism 44 rotates the plurality of left leg portions 52a ₁ , 52a ₂ , 52a ₃ and the right leg portions 52b ₁ , 52b ₂ , 52b ₃ around each joint axis J1 extending substantially in the horizontal direction, and elevates the support base 54. (See the arrow shown in FIG. 1).

The first and second arm portions 46a and 46b are provided on the support base 54, respectively. The first arm portion 46a is provided above the second arm portion 46b. The first arm portion 46a has a first arm 56a and a second arm 57a. The first and second arms 56a and 57a rotate around the joint axis J2 (see FIGS. 1 and 2) and the first arm portions 46a and 46b expand and contract by the substrate transfer robot 20. The first end effector 48a provided at the tip of the arm 56a can be moved in the transport direction.
The second arm portion 46b is configured in the same manner as the first arm portion 46a. Therefore, the substrate transfer robot 20 can move the second end effector 48b in the transfer direction.
As described above, the substrate transfer robot 20 can transfer the liquid crystal glass substrates G placed on the first and second end effectors 48a and 48b, respectively.

  As shown in FIG. 3, the first end effector 48a extends from the frame 60 attached to the distal end portion of the second arm 57a with a space in the direction intersecting the longitudinal direction of the frame 60, for example, It has four fork members 62a-62d. Since the second end effector 48b has the same configuration as the first end effector 48a, detailed description thereof will be omitted below.

As shown in FIG. 4, the frame 60 is provided with solenoid valves 64a to 64d, pressure sensors 66a to 66d, an A / D converter 68, a parallel / serial converter 72, and a transmitter 74.
For example, four suction pads 76 are provided on the surface of each of the fork members 62a to 62d on the side on which the liquid crystal glass substrate G is placed. The substrate transfer robot 20 can air-suck the liquid crystal glass substrate G with these suction pads 76 and hold and transfer the liquid crystal glass substrate G.

As shown in FIG. 5, the pressure piping system (hereinafter simply referred to as “system”) of the suction pad 76 is configured separately for each of the fork members 62a to 62d, for example. Specifically, the four suction pads 76 provided on the first fork member 62a are the system 1, and the four suction pads 76 provided on the second fork member 62b are the system 2, the third fork member. The four suction pads 76 provided on 62c are provided separately for the system 3, and the four suction pads 76 provided on the fourth fork member 62d are provided separately for the system 4.
The “robot main body” shown in FIG. 5 refers to the substrate transport robot 20 excluding the first and second end effectors 48a and 48b (the same applies hereinafter).

  Solenoid valves 64a to 64d provided in each system can control adsorption and non-adsorption of the adsorption pad 76. Accordingly, the adsorption and non-adsorption of the liquid crystal glass substrate G is controlled for each system.

Pressure sensors 66 a to 66 d provided in each system can detect the suction pressure of the suction pad 76. The pressure sensors 66a to 66d can output the detected adsorption pressure as an analog signal.
The analog signals output from the pressure sensors 66a to 66d are converted into digital signals and output by, for example, a 4-channel A / D converter 68 (see FIGS. 4 and 6). Each output of the A / D converter 68 is converted from a parallel signal to a serial signal by a parallel / serial converter 72 and output. The output of the parallel / serial converter 72 is transmitted by the transmitter 74. The signal transmission method may be a time division cyclic transmission method.

The serial signal transmitted by the transmitter 74 is transmitted to a receiver 82 provided inside the control device 30 via a signal cable (see FIGS. 6 and 7). The signal cable is wired from the first end effector 48a shown in FIG. 1 to the inside of the first arm portion 46a, the lifting mechanism 44, the traveling mechanism 42, and the control device 30.
As described above, since the adsorption pressure data is digitally converted and transmitted, the noise resistance performance of the signal is improved as compared with the case where the data is transmitted as an analog signal. Further, since the suction pressure signal is serially converted and transmitted, the number of signal cables wired to the substrate transport robot 20 is reduced.

As illustrated in FIG. 6, the control device 30 includes the above-described receiver 82, a data acquisition unit 84, and a determination unit 86. The data acquisition unit 84 and the determination unit 86 are realized by software executed by a CPU, for example.
As described above, the receiver 82 receives the serial signals transmitted from the transmitters 74 provided in the first and second end effectors 48a and 48b, respectively.

The data acquisition unit 84 can acquire adsorption pressure data (see FIG. 9) from the receiver 82 for each system of the first and second end effectors 48a and 48b. The data acquisition unit 84 can store the acquired data in a data storage unit 88 configured by, for example, a flash memory or a hard disk. The data of the suction pressure is from the time when the suction pad 76 sucks the liquid crystal glass substrate G to the time when the suction pressure of the suction pad 76 is stabilized and the glass substrate G sucked by the suction pad 76 starts moving. It includes adsorption pressure data (transient data D) detected by the pressure sensors 66a to 66d.
Here, it is difficult to strictly specify the moment when the suction pad 76 sucks the liquid crystal glass substrate G based on the suction pressure. The fact that the suction pad 76 has sucked the liquid crystal glass substrate G is determined by a sudden change in the suction pressure change rate as shown in part A of FIG. 9, for example, a change point where the rising suction pressure further increases. At C (time t1), it can be determined (defined) that the suction pad 76 has sucked the liquid crystal glass substrate G. Further, the fact that the adsorption pressure is stable (adsorption pressure 100%) is determined by the fluctuation of the adsorption pressure falling within a predetermined range.

  Based on the transient data D for each system stored in the data storage unit 88, the determination unit 86 determines whether the first to third conditions serving as a determination criterion for determining whether or not the suction pad 76 is worn out. Judge every time.

The first condition is that, based on the transient data D, the time necessary for the suction pressure of the suction pad 76 to change from the first magnitude to the second magnitude has exceeded a predetermined time. is there.
The first magnitude can be, for example, the magnitude of the suction pressure when the suction pad 76 contacts the liquid crystal glass substrate G. The second magnitude can be the magnitude of the suction pressure when the suction pressure of the suction pad 76 is stable and the glass substrate G sucked by the suction pad 76 starts moving. That is, the first condition can be, for example, that the time T1 from time t1 to time t2 (time when the adsorption pressure is stable) shown in FIG. 9 exceeds a predetermined time.
If the determination unit 86 determines that the first condition is satisfied, the determination unit 86 outputs a first alarm that the suction pad 76 is worn.

The second condition is a transient data D, is to exceeding the size mismatch degree predetermined the reference transient data D ₀ corresponding to the transient data D. Here, the reference transient data D ₀ is the pressure sensor 66a until the suction pads 76 when the suction pad 76 is not worn adsorption pressure in the suction pad 76 from the adsorbing liquid crystal glass substrate G is stabilized -66d is the data of the adsorption pressure detected. Reference transient data D ₀ is acquired in advance and stored in the reference data storage unit 90 (see FIG. 6). Predetermined magnitude of the second condition is, for example, ± 10% of the reference transient data _{D 0} may be (boundary RL1, RU1 shown in FIG. 10).
Determination unit 86 calculates the transient data D, and mismatch degree between the reference transient data D _0. If the determination unit 86 determines that the second condition is satisfied, the determination unit 86 outputs a second alarm that the suction pad 76 is worn.

The third condition is that the degree of inconsistency between the transient data D and the moving average data D1 of the transient data D (an example of correlation data) exceeds a predetermined size. The predetermined size can be, for example, ± 10% of the moving average data D1 (boundaries RL2 and RU2 shown in FIG. 11).
The determination unit 86 obtains the degree of inconsistency between the transient data D and the moving average data D1 of the transient data D. If the determination unit 86 determines that the third condition is satisfied, the determination unit 86 outputs a third alarm that the suction pad 76 is worn.

The fourth condition is that the number of output times of the first to third alarms exceeds a predetermined value.
The determination unit 86 accumulates and counts the number of outputs each time one of the first to third alarms is output. If the determination unit 86 determines that the fourth condition is satisfied, the determination unit 86 outputs a fourth alarm that the suction pad 76 is worn.

Next, the operation in which the robot system 10 detects wear of the suction pad 76 will be described with reference to FIG. This wear detection operation is executed every time the substrate transport robot 20 sucks the liquid crystal glass substrate G.
First, as advance preparation, and stores the reference transient data D ₀ in the aforementioned reference data storage unit 90.

(Step S1)
The substrate transfer robot 20 moves the first end effector 48a below the liquid crystal glass substrate G. Each solenoid valve 64a to 64d is opened to generate a suction pressure on the suction pad 76.

(Step S2)
The data acquisition unit 84 starts acquiring the adsorption pressure data. Data acquired by the data acquisition unit 84 is stored in the data storage unit 88. The substrate transfer robot 20 moves the first end effector 48a from below the liquid crystal glass substrate G to above.
Next, the suction pad 76 of the first end effector 48a contacts the liquid crystal glass substrate G. When the suction pad 76 sucks the liquid crystal glass substrate G, the data shown in the A part of FIG. 9 appears in the data acquired by the data acquisition unit 84. The substrate transfer robot 20 moves the first end effector 48a further upward.

(Step S3)
If the data on the base adsorption pressure is stable, the process proceeds to the next step S4. If the adsorption pressure data is not stable, the data acquisition unit 84 continues the data acquisition shown in step S2.

(Step S4)
The data acquisition unit 84 ends the data acquisition.

(Step S5)
The determination unit 86 determines whether or not the first to third conditions are satisfied. If the first to third conditions are satisfied, the next step S6 is executed. If the first to third conditions are not satisfied, the operation is terminated.

(Step S6)
The determination unit 86 outputs corresponding first to third alarms.

(Step S7)
The determination unit 86 increases the number of alarm outputs by one. In this step, for example, when the first and second alarms (a total of two alarms) are output, the number of alarm outputs is increased twice.

(Step S8)
The determination unit 86 further determines whether or not the fourth condition is satisfied. If the first to third alarm output counts are accumulated and the fourth condition is satisfied, the next step S9 is executed. If the fourth condition is not satisfied, the operation of detecting the wear of the suction pad 76 is terminated.

(Step S9)
The determination unit 86 outputs a fourth alarm.
Note that the determination unit 86 can output only the fourth alarm without outputting the first to third alarms to the outside. If there is a large variation in the flatness of the liquid crystal glass substrate G to be conveyed, depending on the liquid crystal glass substrate G, the suction may not be successful, and the wear of the suction pad 76 may be erroneously detected. By outputting only the fourth alarm, erroneous detection is suppressed even if the flatness of the liquid crystal glass substrate G varies greatly.

Thereafter, every time the liquid crystal glass substrate G is sucked, the robot system 10 repeats steps S1 to S9 described above to detect wear of the suction pad 76.
According to the present embodiment, wear of the suction pad 76 is detected in advance. In particular, since the suction pad 76 is provided separately for each system, the worn suction pad 76 is easily identified.

  From another point of view, the above-described embodiment includes 1) a suction pad that sucks an article, 2) a pressure sensor that detects the suction pressure of the suction pad, and 3) a suction pad after the suction pad sucks the article. The determination unit that determines the wear of the suction pad based on the transient data of the suction pressure detected by the pressure sensor until the suction pressure becomes stable can be regarded as a suction device that sucks the article. This suction device can be applied to devices other than the robot system, such as a picking device.

In addition, this invention is not limited to the above-mentioned embodiment, The change in the range which does not change the summary of this invention is possible. For example, a case where the invention is configured by combining some or all of the above-described embodiments and modifications is also included in the technical scope of the present invention.
The form of the robot may be arbitrary. For example, the number of axes of the arm may be arbitrary. Also, a single arm may be used instead of a double arm. Furthermore, the robot may be, for example, a 6-axis (or 7-axis) industrial robot having an end effector at the tip of the arm.
The system may not be divided for each fork member. For example, when transporting transported articles having different sizes, the systems can be divided according to the suction pads that come into contact with the transported objects.
The determination unit can output only some of the first to fourth alarms.
The correlation data is not limited to the moving average data D1. Another example of the correlation data is new data obtained by performing some processing on the transient data D.

10: Robot system, 20: Substrate transport robot, 30: Control device, 42: Traveling mechanism, 44: Lifting mechanism, 46a: First arm unit, 46b: Second arm unit, 48a: First end effector, 48b: second end effector, 52a ₁ , 52a ₂ , 52a ₃ : left leg, 52b ₁ , 52b ₂ , 52b ₃ : right leg, 54: support base, 56a: first arm, 57a: second 60: frame, 62a, 62b, 62c, 62d: fork member, 64a, 64b, 64c, 64d: solenoid valve, 66a, 66b, 66c, 66d: pressure sensor, 68: A / D converter, 72: Parallel / serial converter, 74: transmitter, 76: suction pad, 82: receiver, 84: data acquisition unit, 86: determination unit, 88: data storage unit, 90 Reference data storage unit, G: LCD panel

Claims (11)

A robot having an end effector provided with a suction pad for sucking a conveyed product and a pressure sensor for detecting a suction pressure of the suction pad;
The suction pad is based on transient data of the suction pressure detected by the pressure sensor from when the suction pad sucks the transported object until the transported object sucked by the suction pad starts moving. And a control system having a determination unit for determining wear of the robot.   The robot system according to claim 1, wherein the determination unit determines in advance a time required for the suction pressure of the suction pad to change from a first magnitude to a second magnitude based on the transient data. A robot system that outputs a first alarm when it is determined that a first condition, that is, a predetermined time has been exceeded. The robot system according to claim 2, wherein the first magnitude is a magnitude of the suction pressure when the suction pad sucks the transported object.
The robot system according to claim 2, wherein the second magnitude is a magnitude of the suction pressure when the transported object sucked by the suction pad starts moving. 4. The robot system according to claim 2, wherein, when the suction pad is not worn, the determination unit waits until the suction pressure of the suction pad is stabilized after the suction pad sucks the conveyed object. The reference transient data corresponding to the transient data obtained from the pressure sensor and the degree of inconsistency between the transient data and
A robot system that outputs a second alarm when it is determined that the second condition that the degree of mismatch exceeds a predetermined size is satisfied. The robot system according to claim 4, wherein the determination unit obtains a degree of inconsistency between the transient data and correlation data correlated with the transient data,
A robot system that outputs a third alarm when it is determined that a third condition that the degree of inconsistency exceeds a predetermined size is satisfied.   6. The robot system according to claim 5, wherein the correlation data is moving average data of the transient data.   6. The robot system according to claim 5, wherein the determination unit counts the number of times of output each time one of the first to third alarms is output, and the number of times of output exceeds a predetermined value. A robot system that outputs a fourth alarm when it is determined that the fourth condition is satisfied. The robot system according to claim 7, wherein the suction pad is provided for each pressure piping system that controls the suction pressure of the suction pad,
The pressure sensor is a robot system provided in each pressure piping system. 9. The robot system according to claim 8, wherein the end effector converts an analog signal output from each pressure sensor into a digital signal and outputs the digital signal.
A parallel / serial converter that converts the output of the A / D converter from a parallel signal into a serial signal and outputs the serial signal;
A transmitter for transmitting a serial signal output from the parallel / serial converter;
The said control apparatus is a robot system which has a receiver which receives the said serial signal which the said transmitter transmitted. The robot system according to claim 9, wherein the end effector includes a frame and a fork member extending from the frame,
The A / D converter, the parallel / serial converter, and the transmitter are provided in the frame;
A robot system in which the suction pad is provided on the fork member. A suction pad for adsorbing articles;
A pressure sensor for detecting the suction pressure of the suction pad;
A determination unit that determines wear of the suction pad based on transient data of the suction pressure detected by the pressure sensor from when the suction pad sucks the article to when the suction pressure of the suction pad becomes stable. And a suction device.

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