KR101585193B1 - End of Arm Tool for determination of Screw Clamping force and Clamping task fail-success of Electric Driver - Google Patents

Abstract

A work tool device for an electric driver robot is provided. The apparatus includes a grip base to receive a gripping force from a driving unit, a gripper jaw coupled to the coarse base and gripping the electric driver according to a gripping force transmitted from the driving unit through the coarse base, And a sensor disposed between the jaw base and the gripper jaw and sensing a reaction force torque transmitted to the gripper jaw when the screw is engaged with the electric screwdriver.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a work tool device for an electric motor driver robot capable of confirming a screw tightening force and a screw tightening error,

Field of the Invention [0002] The present invention relates to an end-effector for a robot, and more particularly, to a work tool device for an electric driver robot that uses an electric screwdriver to fasten a screw.

Industrial robots are widely used to replace workers in production lines that require repetitive tasks.

Such an industrial robot is composed of a manipulator constituting an arm and an end-effector mounted on the end of the manipulator and performing various tasks for describing a human hand motion.

The end-effector can be used for tasks that require extreme environments such as welding, repetitive tasks such as pick and place, and precision-requiring tasks such as bolting.

Currently, end-effector technologies include robot hand (DLR Hand, Robonaut Hand, and Shadow Hand) that reproduce human hand shape and motion, and dedicated gripper (Barret, RobotiQ, and Schunk Gripper).

In particular, the robot hand has various versatility and versatility to perform various tasks such as human hands and adapt to various work environments, but it is expensive and difficult to implement in terms of mechanism structure and control.

On the other hand, a bolting operation using such a dedicated work tool is a method of gripping a push-start type electric screwdriver and fastening a dedicated screwdriver by pressing a screw for a predetermined time. At this time, it is necessary to confirm whether the screw is tightened properly, and in the past, it was confirmed that the screw was tightened with the naked eye of the operator during the bolting operation. However, it is not accurate to confirm the success of screw tightening with the naked eye.

Therefore, it is an object of the present invention to provide a work tool for an electric driver robot capable of confirming the success of a fastening operation in the course of fastening a screw using an electric screwdriver, without any expensive equipment, .

According to an aspect of the present invention, there is provided a working tool device for an electric motor driver robot, including a first base (122) and a second base (124) A jaw base for receiving a gripping force decomposed in a direction; A first gripper jaw 132 integrally formed with the first jaw base 122 and a second gripper jaw 134 movably coupled with the second jaw base 124 in the y axis direction, Axis direction and the y-axis direction in accordance with a gripping force transmitted from the driving unit through the first base 122 and the second base 124 Gripper jaw; And a second gripper boss (134) disposed between the second base base (124) and the second gripper boss (134), wherein the yaw axis And a sensor for sensing a force component formed in the direction of the arrow.

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According to the present invention, a gripper applied to a work tool for an electric screwdriver robot that is easy to check for screw tightening during a bolting operation without the assistance of an operator is implemented, so that a general low- Unlike the conventional method of confirming the screw tightness in the cell and confirming the screw tightness in the existing bolting operation using the robot and judging the success or failure of the operation with the naked eye of the operator, the screw tightening torque is measured, As well as confirmation errors.

FIG. 1 is a view showing a work tool device for an electric motor driver robot according to an embodiment of the present invention, wherein (A) is a side view of the work tool device viewed from the side, and (B) Fig.
FIG. 2 is a view for explaining a force component acting on a gripper tank due to reaction force torque when a screw is fastened according to an embodiment of the present invention.
3 is a view illustrating a decoupled structure between a gripper bar and a bar base according to an embodiment of the present invention.
Fig. 4 is a diagram showing a state in which alignment between an electric screwdriver and a screw is not performed before screwing.
FIG. 5 is a view showing a state in which the screws are fastened in the wrong direction after screw fastening; FIG.

These and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. And is intended to provide a person with a complete disclosure of the scope of the invention, and the invention is defined by the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that " comprises, " or "comprising," as used herein, means the presence or absence of one or more other components, steps, operations, and / Do not exclude the addition.

According to the present invention, a work tool device for an electric motor driver robot is provided which can confirm screw tightening without the help of an operator.

The work tool device for this electric driver robot measures the reaction force torque immediately before screw tightening and confirms whether the screw is tightened. In particular, the present invention is characterized in that the reaction force torque is measured using a load cell mounted according to the mechanical structure proposed in the present invention, without using an expensive F / T (Force / Torque) sensor in the measurement method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a work tool device for an electric motor driver robot according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a side view of a work tool device for an electric driver robot according to an embodiment of the present invention. FIG. 1 (A) is a side view of the work tool device, and FIG. 1 (B) (Top view) as viewed from above.

1, a work tool device for an electric motor driver robot according to an embodiment of the present invention includes a driving unit 110, a jaw base 120, a gripper jaw 130, and a sensor 125 ).

The driving unit 110 generates a gripping force for gripping the body 20 of the electric screwdriver 10.

The jaw base 120 receives the gripping force from the driving unit 110 and transmits the gripping force to the gripper jaw 130. The coarse base 120 according to one embodiment includes a first coarse base 122 and a second coarse base 124. The first and second base bases 122 and 124 move in directions facing each other (hereinafter referred to as a gripping force direction) according to the holding force. Hereinafter, it is assumed that the gripping force direction is the X-axis direction.

The gripper 130 is mechanically decoupled from the coarse base 120 so that the gripper 130 can be moved to the body of the electric screwdriver 10 according to the gripping force transmitted from the driving unit 110 through the coarse base 120 20). To this end, the gripper jaw 130 includes a first gripper jaw 132 and a second gripper jaw 134. The first and second gripper tanks 132 and 134 receive the gripping force in the X axis direction through the first and second coarse bases 122 and 124 to grip the body 20 of the electric drier 10 . In particular, the second gripper jaw 134 according to one embodiment is configured to be movable in the Y axis direction perpendicular to the X axis direction, which is the gripping force direction, according to the mechanical coupling structure proposed in the present invention.

The sensor 125 is disposed between the second base base 124 and the second gripper base 134 in accordance with the mechanical coupling structure so that the screw 30 is fixed to the work object 40 The reaction force torque transmitted to the gripper jaw is sensed. In one example, the sensor 125 may be a load cell.

 Here, the reaction force torque transmitted to the gripper jaw may be divided in the Y axis direction which is a direction perpendicular to the X axis direction, which is the gripping force direction.

Therefore, the sensor 125 has a mechanical coupling structure disposed between the second group base 124 and the second gripper group 134 to measure the force in the Y-axis direction.

The fact that the reaction force torque can be sensed through the arrangement structure of the sensor 125 can be understood by analyzing the force component acting on the gripper tank 130.

2 is a view showing a force component acting on the gripper due to the reaction torque generated in the screwing operation by the electric screwdriver according to the embodiment of the present invention.

2, a reaction force acts on the electric screwdriver 10 due to the resistance of the screw surface when screwing the screw, and as the gripper 130 grips the body 20 of the electric screwdriver 10, The reaction forces f ₁ and f ₂ act on the gripper jaw 130 by the diameter of the body 20 of the driver 10.

The reaction forces f ₁ and f ₂ can be decomposed into Y, which is perpendicular to the gripping force direction X, as shown in FIG.

Therefore, the measurement position of the sensor 125 such as the load cell is designed in the Y-axis direction, which is the vertical direction of the gripping force, in order to avoid overlapping with the gripping force and cancel each other out. At this time, in order to measure the force in the Y direction using the load cell in the rigid base base 124, a mechanically decoupled structure is required.

3 is a diagram showing a mechanically decoupled structure between a gripper bar and a bar base according to an embodiment of the present invention.

3, in order to measure the force in the Y-axis direction perpendicular to the gripping force of the gripper jaw 130, the gripper jaw 134 is fixed to the jaw base 124 in such a manner that the gripper jaw 134 can linearly move in the vertical direction of the gripping force. Decoupled from each other.

To this end, two guide grooves 134-1 and 134-2 are formed in the second gripper jaw 134 in the vertical direction of the gripping force, that is, in the Y-axis direction. The guide grooves 134-1 and 134- 2 are provided with guide rails 134-1A and 134-2B, respectively.

Guide rails 134-1A and 134-2 formed on the inner side walls of the two guide grooves 134-1 and 134-2 are formed in the second base base 124 that mechanically engages with the second gripper base 134. [ Two guide protrusions 124-1 and 124-2 are formed to be coupled to the first guide protrusions 2B.

Therefore, when a reaction force acts on the electric screwdriver 10 due to the resistance of the screw surface at the time of screw tightening, a reaction force acts on the second gripper jaw 134 gripping the body 20 of the electric screwdriver 10 .

By this reaction force, the second gripper jaw 134 linearly moves along the extension direction of the two guide projections 124-1 and 124-2, that is, the Y-axis direction. At this time, the load cell 125 disposed between the second gripper group and the second group base (or between the two guide protrusions 124-1 and 124-2) moves in the Y-axis direction in the second gripper group Measure the force in the Y-axis direction.

That is, in the principle of being measured, the force component in the X-axis direction among the reaction torque components transmitted to the second gripper member 134 is transmitted through the guide protrusions 124-1 and 124-2, The force in the X axis direction is not detected by the load cell 125 due to the mechanical coupling structure between the pair of bases 124 and the second gripper tanks 134. [

On the other hand, since the second gripper trough 134 can move freely on the guide protrusions 124-1 and 124-2 of the second trough base 124, the reaction force torque component transmitted to the second gripper trough 134 The force component in the middle Y-axis direction can be detected by the load cell 125. [

The detected force component in the Y-axis direction can be confirmed not only in screw fastening force but also in screw fastening success, by comparing with the setting reference value (or set torque) that determines whether or not the screw fastening force is successful.

Here, for the initial contact point of the load cell 125 and the backlash of the second gripper tank 134, a stroke is formed between the second gripper tank 134 and the second tank base 124. For example, the stroke may be limited to 1 mm.

As described above, according to the mechanical coupling structure between the gripper jaw and the jaw base proposed in the present invention, from the reaction force torque transmitted to the gripper jaw 134 through the arrangement structure of the load cells 125 arranged, Or not.

In addition, as shown in FIG. 4, when the screw is not aligned between the electric screwdriver and the screw before the screw tightening operation and when the screw is screwed in the wrong direction after the screw tightening operation as shown in FIG. 5, The gap between the bits causes the electric screwdriver to idle. In this case, a torque smaller than the reference value (or set torque) is detected by the load cell, so that it is possible to judge the failure of the screw tightening operation. This makes it possible for the operator to avoid the trouble of confirming the fastening operation during the assembling work and to utilize it in the industrial field due to immediate error response.

As described above, the present invention applies a mechanically decoupled structure to an electric screwdriver dedicated gripper, thereby realizing an easy gripper for confirming the fastening of the screw in the bolting operation. In addition, the present invention realizes a gripper capable of confirming the screw tightening even in a general low-cost load cell without using an expensive F / T sensor in confirmation of the fastening.

As a result, unlike the prior art in which the confirmation of the screw tightening and the success or failure of the operation are judged by the naked eye of the operator in the conventional bolting operation using the robot, the screw tightening torque is measured in the screw tightening operation, You can check for errors.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Various modifications may be made by those skilled in the art. For example, the linear movement of the gripper bar relative to the coarse base is not limited to the structure shown in FIG. 3, but can be replaced by using various motion mechanisms such as an LM guide, a slide pack, and a linear bush.

In this embodiment, the load cell is exemplified in order to measure the reaction force acting on the gripper trough. However, if the installation position of the sensor proposed in the present invention is applied, the reaction force acting on the gripper tank The ability to measure torque can be appreciated by those skilled in the art. Accordingly, these modifications should not be understood individually from the technical idea or viewpoint of the present invention.

Claims (10)

1. A work tool for an electric screwdriver robot for fastening a screw using an electric screwdriver,
A jaw base including a first set base 122 and a second set base 124 and receiving a grasping force decomposed in the x and y axis directions from the driving unit;
A first gripper jaw 132 integrally formed with the first jaw base 122 and a second gripper jaw 134 movably coupled with the second jaw base 124 in the y axis direction, Axis direction and the y-axis direction in accordance with a gripping force transmitted from the driving unit through the first base 122 and the second base 124 Gripper jaw; And
And a second gripper 134 which is disposed between the second grip base 124 and the second gripper 134 so as to move in the y-axis direction in response to a reaction force torque transmitted to the second gripper 134 at the time of screw- A sensor for sensing a force component
And a work tool for an electric motor driver robot.
delete 2. The gripper according to claim 1,
Two guide grooves formed in the y-axis direction,
And guide rails formed on inner side walls of the two guide grooves, respectively.
4. The apparatus of claim 3,
And two guide protrusions respectively inserted into the two guide grooves,
The second gripper bar
And the guide protrusion moves linearly in the y-axis direction according to the gripping force.
5. The sensor according to claim 4,
And the guide projections are disposed between the two guide projections.
2. The gripper according to claim 1,
Wherein the base is coupled to the base by any one of a guide, a slide pack, and a linear bush so as to linearly move in a direction perpendicular to the gripping force, Work tools for. delete delete delete delete

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