JP2001287190A - Robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sufficient safety in an overload on the wrist part of a robot arm while minimizing a reduction in working efficiency. SOLUTION: An overload protection unit 19 for holding a hand 15 of a robot arm by means of supplied air pressure is disposed between a wrist part 14a and the hand 15 of the robot arm. An air supply mechanism 20 for supplying the air pressure comprises a low-pressure regulator 27, a high-pressure regulator 28 and a selector valve 29, and has a setting value (overload point) switchable between a low pressure (10 kg) and a high pressure (20 kg). A pressure switch 30 is connected to air supply piping 23. A robot controller controls the selector valve 29 in accordance with a working program, or switches it to the low- pressure side when safety is necessary and to the high-pressure side when no risk of a person's being in a hemmed position is present, and triggers an emergency stop when the pressure switch 30 is operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot body having a hand tool attached to a wrist of a robot arm.
The present invention relates to a robot that performs a predetermined operation by controlling operation according to an operation program.

[0002]

For example, in a production line of automobile parts, a so-called setup change is performed by a mobile robot having a robot body (for example, a 6-axis robot arm) mounted on an automatic guided vehicle (AGV). And the like.
In such a system, it is necessary to ensure safety when a worker (person) and a mobile robot coexist and perform work or the like.

In this case, a robot having a motor output of a robot arm of 80 W or less is treated as being out of the scope of the robot standard, so that a large-scale safety measure is not required. However, at a point where a sharp projection or a person may be caught, the load acting on the robot arm (hand) is set to, for example, 15 kg or less (in-house safety standard), or a gap that may be caught is eliminated. If countermeasures are necessary, if they cannot be done, the entire work area of the robot will be covered with a safety cover, similar to the robot standard,
Extensive measures such as providing a safety mat around the work area are required, which is not preferable in terms of space and work efficiency.

[0004] Therefore, in a robot having a motor output of 80 W or less, an overload prevention unit using air pressure is provided between the wrist of the robot arm and the hand tool (for example, Takano Bearing Co., Ltd.). "OLP80" etc.). The overload prevention unit includes a main body attached to a wrist of a robot arm and a tool plate to which a hand tool is attached. An air supply source (compressor) is provided in the main body.
The air is supplied so as to be supplied with a predetermined pressure.

Accordingly, the tool plate (hand tool) is held by the air pressure supplied into the main body of the overload prevention unit, and the hand tool is overloaded (for example, a load exceeding 10 kg) exceeding its holding force. Is activated, the holding state of the tool plate is released, and the limit switch outputs an overload detection signal. Then, based on the signal of the limit switch, the robot controller makes an emergency stop of the robot body.

However, a relatively low value is set as an overload point at which the above-mentioned overload prevention unit operates, with an emphasis on safety (for example, the holding force due to air pressure is set to 1).
In the case of 0 kg, for example, a frictional force when the workpiece is displaced or moved or the robot arm is rotated at a high speed, for example, easily exceeds the overload point. For this reason, an emergency stop (a so-called choke stop) is performed relatively frequently, which causes a problem that the working efficiency is reduced. On the other hand, if the overload point is set to a large value, the security will be inferior this time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to minimize the decrease in work efficiency,
An object of the present invention is to provide a robot capable of ensuring sufficient safety when an overload is applied to a wrist of a robot arm.

[0008]

According to the present invention, there is provided a robot comprising: an overload detecting means for detecting whether a load acting on a wrist of a robot arm exceeds a set value; Emergency stop means for stopping the operation of the robot body when a detected load is detected, and wherein the set value is configured to be switchable on a work program (the invention of claim 1). .

According to this, if the load applied to the wrist of the robot arm exceeds a set value when the hand tool pinches a person or collides with a peripheral device, the operation of the robot main body is performed by the emergency stop means. Is stopped, it is possible to improve the safety when the worker (person) and the mobile robot coexist and perform work or the like. in this case,
Since the set value determined to be overloaded can be switched on the work program, the set value (overload point) is set at a work place or work process where a person may be pinched, for example.
By setting to a low value, high security can be ensured.

In a work place or a work process where there is no risk of a person being pinched, setting the set value (overload point) to a relatively high value enables the robot arm to move at a high speed, for example. Exceeding the overload point can be suppressed, and efficient work can be performed. Therefore, according to the first aspect of the invention, there is obtained an excellent effect that it is possible to secure sufficient safety when an overload is applied to the wrist of the robot arm while minimizing a decrease in work efficiency. Is what you can do.

More specifically, the overload detecting means includes:
An intervening device that is interposed between the wrist of the robot arm and the hand tool, holds the hand tool by the supplied air pressure, and releases the holding when an overload exceeding the air pressure acts on the hand tool. A configuration including a load prevention unit can be used, and the set value can be switched by switching the air pressure (the invention of claim 2).
According to this configuration, by changing the air pressure supplied to the overload prevention unit, it is possible to easily switch the set value (overload point). together,
The impact when the hand tool collides with the peripheral device can be released, and the hand tool and the peripheral device can be protected.

In this case, in this type of overload prevention unit, it is detected by a limit switch (or proximity switch) that the internal air has been released due to the overload (the holding of the hand tool has been released). Although the configuration is general, the response using the limit switch tends to be slightly poor. Therefore, a pressure switch for detecting a pressure change in the air supply pipe with respect to the overload prevention unit may be provided, and the overload may be detected by the pressure switch (the invention of claim 3). Can detect an overload.

[0013] Alternatively, the overload detecting means may include a force sensor interposed between the wrist of the robot arm and the hand tool and detecting a force acting on the hand tool. 4 invention). According to this, switching of the set value can be easily performed by, for example, a software configuration of a controller, and the force sensor can be used for force sense control of the wrist.

The set value can be determined according to the size of the gap between the working hand tool and peripheral equipment such as equipment (the invention of claim 5). As a result, at the operation point where the gap between the hand tool and the peripheral device may pinch a finger or the like of a person, the set value is reduced, and when the gap is zero or small, the set value is increased. Switching control becomes possible, and a set value suitable for the purpose can be determined.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a case where a so-called setup change operation is performed by a mobile robot on a production line of an airbag module for an automobile (claims 1, 2, 3, and 3). 5))
This will be described with reference to FIGS. The mobile robot in this embodiment has a motor output of 80 W or less.

First, FIG. 6 schematically shows a layout configuration of a production line 1 for an airbag module. Although not described in detail, the production line 1 has a passage 2 extending in the front-rear direction at the center and through which a worker can work, and a plurality of assembling facilities 3 along left and right portions of the passage 2.
have. Among them, a conveyor device 4 is provided which conveys a workpiece from the back side to the front side in the figure along the assembling equipment 3 on the left side in the figure. In addition, a pallet setup position 5 is provided at the inner left side of the assembling equipment 3.
At the pallet setting position 5, a pallet 6 (see FIG. 5 only) for holding an airbag module (not shown) is arranged.

For example, in this production line 1, a plurality of types of airbag modules are produced for each type of vehicle, and in this case, five types of different pallets 6 are used according to the type. I have. The mobile robot according to the present embodiment, which will be described later, is configured to automatically execute a supply / exchange operation (setup change operation) of the pallet 6 prepared and arranged at the pallet setup position 5.

At this time, the production line 1 is provided on the left side of the assembling equipment 3 with five pallet storage tables 7 arranged side by side, and each of them has a pallet 6 of a different type. It is to be accommodated. And, extending in the front-back direction along the pallet storage table 7,
A traveling path 8 for the mobile robot is provided. The traveling path 8 is provided so as to extend to the standby position at the back and to branch right at the back side and extend rightward toward the setup change work position near the pallet setup position 5. Further, a temporary pallet table 9 is provided in the vicinity of the setup change operation position. A guide line 10 made of, for example, a magnetic tape is laid on the traveling path 8.

FIG. 5 shows an external configuration of a mobile robot 11 as a robot according to the present embodiment. The mobile robot 11 is mounted on an automatic guided vehicle (AGV) 12 which is formed in a substantially rectangular box shape slightly longer in the front-rear direction (left and right in the figure) as a whole.
The robot body 13 is mounted. In this case, the robot body 13 is configured to include a robot arm 14 composed of, for example, a six-axis arm attached to the rear end side of the automatic guided vehicle 12. As will be described later, a hand 15 as a hand tool for gripping the pallet 6 and performing transfer and the like is attached to the wrist portion 14a at the tip of the robot arm 14.

Although not shown in detail, the automatic guided vehicle 1
2 has a plurality of wheels 16 on the bottom and a traveling mechanism for driving the driving wheels among them. Also,
In the automatic guided vehicle 12, a robot controller 17 (see FIG. 2) mainly composed of a microcomputer, a battery serving as a power supply, and the like are also provided. A pallet storage shelf 18 on which a large number of pallets 6 are stacked so as to be stacked in multiple stages is provided on the upper surface of the automatic guided vehicle 12 (in front of the mounting position of the robot arm 14).

Although not shown, a pair of front and rear guide sensors for detecting the guide line 10 laid along the traveling path 8 are provided at the bottom of the automatic guided vehicle 12, A stop marker sensor and the like for detecting a stop marker provided at the setup change operation position are also provided. In addition, an obstacle sensor and the like for detecting an obstacle are provided on the peripheral wall of the automatic guided vehicle 12.

In this embodiment, as shown in FIG.
The hand 15 is attached to the wrist 14 a of the robot arm 14 via an overload prevention unit 19. The robot body 13 includes the overload prevention unit 1.
9 is provided with an air supply mechanism 20 for supplying a predetermined air pressure. In this embodiment, the overload prevention unit 19 and the air supply mechanism 20 constitute overload detection means for detecting whether the load acting on the wrist 14a (hand 15) of the robot arm 14 exceeds a set value. It has become so.

As shown in FIG. 3, the overload prevention unit 19 is, for example, a commercially available “OL” manufactured by Takano Bearing Co., Ltd.
As is well known, the main body 21 includes a cylindrical main body 21 having a hollow inside, and a tool plate 22 provided in the main body 21. A wrist 14a of the robot arm 14 is connected to the upper surface of the main body 21, and a through hole 21a is formed in the center of the bottom wall of the main body 21. Further, the input port of the main body 21 is connected to the tip of the air supply pipe 23 of the air supply mechanism 20.

On the other hand, the tool plate 22
A disk-shaped mounting plate 22a positioned below the main body 21 to which the hand 15 is mounted;
1 and a shaft portion 22c which penetrates through the through hole 21a and connects them.
And are integrally formed. Further, a convex portion 22d is formed on the lower surface side of the press-contact plate 22b, and an O-ring 22e is provided on the outer peripheral portion, and an inner bottom surface of the main body portion 21 corresponds to the convex portion 22d. A recessed portion 21b is provided.

As a result, when the pressure in the main body 21 becomes high,
The press-contact plate 22b is pressed against the inner bottom surface of the main body 21 in an air-tight manner to hold the mounting plate 22a and thus the hand 15 fixedly, and to apply the air pressure in the main body 21 to the hand 15 and thus the mounting plate 22a. When an excessive load is applied, the pressure contact of the pressure contact plate 22b is released, and the holding of the hand 15 is released.

On the other hand, the air supply mechanism 20 is configured as follows. That is, the pipe from the compressor 24 serving as a pressure source branches into a low-pressure pipe 25 and a high-pressure pipe 26, and a low-pressure regulator 27 is provided at an intermediate part of the low-pressure pipe 25, A high pressure regulator 28 is provided in the section. The distal ends of the low-pressure side pipe 25 and the high-pressure side pipe 26 are connected to the input ports of the switching valve 29, respectively. The output port of the switching valve 29 is connected to the base end of an air supply pipe 23 made of a flexible tube.
Further, a pressure switch 30 for detecting a pressure change in the air supply pipe 23 is provided at an intermediate portion of the air supply pipe 23.

When the switching valve 29 is located on the low pressure side as shown in FIG. 1, a low air pressure is supplied into the main body 21 of the overload prevention unit 19, and the switching valve 29 is turned off. Is switched to the high pressure side, a high air pressure is supplied into the main body 21. And the pressure switch 30
Is the set value (overload point) when the main body 21 is opened to the atmosphere, that is, when the tool plate 22 (hand 15) is opened.
It operates when a load exceeding is applied.

In this case, in the present embodiment, the low-pressure regulator 27 adjusts the supply air pressure to 0.2, for example.
The pressure is adjusted to MPa, and the overload point in the overload prevention unit 19 is set to 10 kg. On the other hand, the high-pressure regulator 28 adjusts the supply air pressure to 0.4 MPa, for example, and the overload point in the overload prevention unit 19 is set to 20 kg. Thus, the overload prevention unit 19, the air supply mechanism 20, and the pressure switch 30 constitute an overload detection unit. By switching the switching valve 29, an overload point (set value) in the overload prevention unit 19 is set. Can be switched in two stages.

Each mechanism described above is controlled by the robot controller 17 as shown in FIG. The robot controller 17 is preliminarily input with a work program and necessary data by an operator using a teaching pendant 31 (or a personal computer or the like). The robot arm 14 (motor of each axis), the hand 15, the compressor 24, the switching valve 29, and a traveling mechanism (not shown) are controlled to execute a setup change operation of the pallet 6.

At this time, the robot controller 17
In this case, a signal from the pressure switch 30 is input, and an on / off control of an emergency stop relay 32 in an operation preparation circuit (emergency stop circuit) (not shown). As described later in the description of the operation, the robot controller 17 has a software configuration that causes a load exceeding a set value (overload point) to be applied to the hand 15 when an ON signal is input from the pressure switch 30, that is, the hand 15. At this time, the emergency stop relay 32 is turned on, the power supply for power is cut off, and the operation of the robot body 13 is stopped. Therefore, the robot controller 17 and the emergency stop relay 32 constitute an emergency stop means.

In the present embodiment, the set value (overload point) is set on the low pressure side (load 10 k
g) and the high pressure side (load 20 kg). The robot controller 17
Is designed to switch the switching valve 29 between a low-pressure side and a high-pressure side during a work in accordance with a set value on the work program.

In this case, the set value (overload point at which the overload prevention unit 19 is opened) depends on the size of the gap between the hand 15 in operation and peripheral devices such as the assembly equipment 3. Is to be determined. That is, as schematically shown in FIG. 4, when the gap is zero (FIG.
In (a)), the set value is set to P1, and in the case of A1 where the gap is small enough to prevent a human finger or the like from entering (FIG. 4 (b)), the set value is set to P2 and the gap is set to a human finger or the like. In the case of A2 (FIG. 4 (c)) in which there is a possibility that "." At this time, it is sufficient to set P1 ≧ P2> P3,
In this embodiment, P1 = P2 = 20 kg, P3 = 10 kg
That is.

Next, the operation of the above configuration will be described. In the production line 1 of the airbag module, the mobile robot 11 takes out a required number of pallets 6 newly required from, for example, one of the pallet storage tables 7 according to the work program, and moves to a setup change work position. At the pallet setup position 5, replacement with an old pallet 6 is performed, and a setup change operation such as moving again and returning the old pallet 6 to the original pallet storage table 7 is automatically executed. During this work, the overload prevention unit 19
A predetermined air pressure is supplied from the air supply mechanism 20 into the main body 21 of the robot arm 14, and the wrist 14 a of the robot arm 14 is
The hand 15 is fixedly held.

During this operation, if the hand 15 pinches the worker's hand or the like between the peripheral equipment and the robot 15 collides with a peripheral device due to a malfunction of the robot arm 14, etc. When the load acting on (the wrist portion 14a of the robot arm 14) exceeds the set value, the tool plate 22 of the overload prevention unit 19 is displaced with respect to the main body portion 21, and the holding of the hand 15 is released, and the main body portion 21 is released. The inside of the air supply pipe 23 is at atmospheric pressure. Then, the pressure switch 30 operates,
The robot controller 17 turns on the emergency stop relay 32 to stop the robot body 13 in an emergency.

Thus, safety when the person and the mobile robot 11 coexist and work is achieved. At the same time, the overload prevention unit 19 releases the impact when the hand 15 collides with the peripheral device, thereby protecting the hand 15 and the peripheral device. When the robot body 13 is emergency stopped, a buzzer or a lamp informs the user of the emergency stop. When returning the robot body 13 from the emergency stop, the operator manually operates the robot arm 1.
4 is moved to a predetermined original position, and the hand 15 (tool plate 22) is returned to the original position with respect to the main body 21, and thereafter, the power of the operation preparation circuit is turned on.

If the above set value is fixed at a relatively low value, the safety is increased, but the frictional force when, for example, the pallet 6 is displaced or the robot arm 14 is turned at a high speed, for example. Just by operating, the set value (overload point) is easily exceeded, and an emergency stop (so-called choke stop) is relatively frequently applied. On the other hand, if the set value (overload point) is fixed to a relatively large value, the security will be inferior.

However, in the present embodiment, the set value determined to be overload is set to 10 kg and 20 kg on the work program according to the size of the gap between the hand 15 and the peripheral device.
kg and two stages. In other words, in a work place or a work process where the gap is large as A2, that is, when a person is likely to be caught, the set value (overload point) is set as low as 10 kg. As a result, when a small load is applied, an emergency stop is applied, whereby high safety can be ensured.

On the other hand, in a work place or a work process where the gap is as small as zero or A1, that is, there is no possibility that a person is pinched, the set value (overload point) is 20 kg.
Is set relatively high, for example, the robot arm 1
Even if the 4 is moved at high speed, a so-called choke stop does not occur, and efficient work can be performed.

As described above, according to the present embodiment, the overload prevention unit 19 is provided so that when the load acting on the hand 15 is overloaded, an emergency stop is applied and the overload prevention unit 19 is provided. Air pressure supplied to
The air supply mechanism 20 that can be switched between the stages is provided, and the overload point is switched between the two stages on the work program, so that the wrist portion 14a of the robot arm 14 is overloaded while minimizing the reduction in work efficiency. It is possible to obtain an excellent effect that sufficient safety can be ensured when it works.

Further, in this embodiment, in particular, since the overload prevention unit 19 which holds the hand 15 by air pressure is employed as the overload detecting means, it is possible to release an impact when the hand 15 collides with a peripheral device. Yes, hand 15
And protection of peripheral devices. Further, since the overload is detected by the pressure switch 30, it is possible to obtain an advantage that the overload can be detected with higher responsiveness as compared with a case where a limit switch or the like is employed.

FIG. 7 shows another embodiment (corresponding to claim 4) of the present invention. This embodiment differs from the above embodiment in that a well-known force sensor 41 is used instead of the overload prevention unit 19 as a component of the overload detection means. As the force sensor 41, for example, a force / torque sensor manufactured by LB Autotech Co., Ltd. or the like can be adopted, which is also attached between the wrist portion 14a of the robot arm 14 and the hand 15, The load acting on the hand 15 is detected.

The detection signal of the force sensor 41 is input to and processed by the load controller 42. The load controller 42 determines that the force acting on the hand 15 exceeds the set value. When it is done, it is configured to apply an emergency stop, and functions as an emergency stop means. Also in this case, the set value (overload point) can be switched in a plurality of stages on the work program. The robot controller 17 performs force sense control of the robot arm 14 based on the force / torque data output from the load controller 42.

According to such a configuration, as in the above-described embodiment, a sufficient safety when an overload is applied to the wrist portion 14a of the robot arm 14 is ensured while minimizing a decrease in work efficiency. The excellent effect that can be obtained can be obtained. In the present embodiment, the set value can be easily and arbitrarily switched by the software configuration in the load controller 42, and fine control can be performed. Further, there is an advantage that the force sensor 41 can be used for force sense control.

In the above embodiment, the set value is switched in two stages. However, the set value may be switched in three or more stages, and the set value (overload point) may be set linearly. It is also possible. Various changes can be made to the configuration of the robot arm and the hand tool. In addition, the present invention can be applied not only to mobile robots but also to fixedly installed robots, and can be applied not only to production lines of automobile parts but also to robots used for various purposes. For example, it can be carried out with appropriate changes within the scope not departing from the gist, for example.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and schematically shows a structure for detecting an overload.

FIG. 2 is a block diagram schematically showing an electric configuration of the robot.

FIG. 3 is a longitudinal sectional view of an overload prevention unit.

FIG. 4 is a diagram showing a state of a gap between a hand tool and peripheral equipment.

FIG. 5 is a side view of a mobile robot.

FIG. 6 is a plan view schematically showing a layout of a production line of an airbag module.

FIG. 7 is a view corresponding to FIG. 1, showing another embodiment of the present invention.

[Explanation of symbols]

In the drawings, 11 is a mobile robot (robot), 13 is a robot body, 14 is a robot arm, 14a is a wrist, 1
5 is a hand (hand tool), 17 is a robot controller (emergency stop means), 19 is an overload prevention unit (overload detection means), 20 is an air supply mechanism, 23 is an air supply pipe, 29 is a switching valve, 30 is Pressure switch, 32 is an emergency stop relay, 41 is a force sensor (overload detection means), 42 is a load controller (emergency stop means)
Is shown.

Claims (5)

[Claims] An operation control of a robot main body having a hand tool attached to a wrist of a robot arm in accordance with a work program sets a load acting on a wrist of the robot arm in a robot performing a predetermined work. An overload detecting means for detecting whether the value exceeds a value, and an emergency stop means for stopping the operation of the robot body when a load exceeding a set value is detected by the overload detecting means. A robot characterized in that a set value is switchable on a work program. 2. The overload detecting means is interposed between a wrist of the robot arm and a hand tool, holds the hand tool by supplied air pressure, and causes the hand tool to exceed the air pressure. The robot according to claim 1, further comprising an overload prevention unit that releases holding when an overload is applied, and wherein the set value is switched by switching the air pressure. 3. The robot according to claim 2, wherein the overload detection means includes a pressure switch for detecting a pressure change in the air supply pipe with respect to the overload prevention unit. 4. The overload detecting means is interposed between a wrist of the robot arm and a hand tool, and includes a force sensor for detecting a force acting on the hand tool. The robot according to claim 1, wherein 5. The apparatus according to claim 1, wherein the set value is determined according to a size of a gap between the hand tool in operation and a peripheral device such as equipment. Robot.