KR101401642B1 - Microgripper for gripping the object using change of frictional force and method for controlling thereof - Google Patents

Abstract

The present invention relates to a micro gripper for gripping an object using a change in friction force and a control method thereof. A micro gripper apparatus for gripping an object related to an example of the present invention, the apparatus comprising: an arm for supporting the object; and a control unit for controlling the grip of the object by changing the friction between the object and the arm And a frictional force control unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro gripper for gripping an object using a friction force change,

The present invention relates to a micro gripper for gripping an object using a change in friction force and a control method thereof.

2. Description of the Related Art As electronic parts have become smaller and lighter in weight, development of microstructures, micro sensors, and actuators using a semiconductor process has been progressing.

In addition, new research is underway to manipulate bio cells by amplifying interest in the human body.

In the past, there was a problem that there was no equipment for moving, fixing, and combining materials such as microstructures or biocells.

In response to this, research on a micro gripper capable of precisely moving a substance such as a micro-structure and an actuator, etc., such as a micro-electronic component and a biocell for a living body, for fixing, moving, It is actively proceeding.

The micro gripper is a mechanism for picking up an object having a small shape or dropping it on a desired place for micro component assembly and ultra precise position control. The micro gripper is classified into a thermal, electrostatic, , Pneumatic (pneumatic), and hybrid (hybrid) driving method.

The heat-driven micro gripper is gripped by using the thermal expansion of the material due to the joule heat generated by the applied voltage, and thus has a disadvantage in that it is difficult to apply to a large driving voltage and energy consumption and to a biotechnology field .

The electrostatic type micro gripper has a disadvantage in that a driving displacement and a gripping force for a voltage are small in a manner of gripping an object by using an electrostatic force between two charged electric charges. Stiction due to electric power may prevent proper placement of objects.

In addition, although the piezoelectric driving micro gripper has the advantage of high precision driving control and gripping force, there is a problem that the inherent hysteresis shape of the piezoelectric material must be minimized.

Since the pneumatic micro gripper uses a pneumatic pressure, it does not require a special energy source such as a voltage, and can be applied to various applications such as bio.

In addition, since it can be manufactured in the same shape as a human finger joint, it has an advantage that the object can be gripped well during gripping.

Meanwhile, the micro-gripping technique applied to the micro gripper currently controls the gripping operation only through the displacement control or the force control.

However, in order to accomplish the object of the micro gripper described above, a surface roughness control of a micro-gripper tip is additionally required for a finer work, and a solution thereof is required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a micro gripper that grips an object using a change in frictional force.

Specifically, the present invention changes the friction coefficient between the object and the arm or the gripper by using a change in the contact area between the object and the arm or the gripper, and changes the frictional force between the object and the arm or gripper using the change in the friction coefficient, The object is to provide a micro gripper that grips an object.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

A micro gripper apparatus for gripping an object related to an example of the present invention for realizing the above-mentioned object, comprising: an arm supporting the object; And a friction control unit for controlling the grip to grip the object.

The frictional force control unit may change a frictional coefficient between the object and the arm using a change in the contact area, and control the frictional force between the object and the cancer to change using the change in the frictional coefficient.

In addition, the frictional force control unit may control at least one of a distance between the object and the arm, and a force that the arm presses the object.

Further, the coefficient of friction may be changed according to the true contact area determined according to the equation. In the above equation,? Is the friction coefficient,? Is the true contact area,? Is the shear stress, and? Is the weight of the object.

The frictional force control unit may include a dielectric elastomer, a conductive polymer, a ferroelectric polymer, an electrostrictive polymer, an ionic polymer / metal composite (IPMC) A piezoelectric ceramic, a piezoelectric polymer, a thermally activated shape memory alloy, a ferromagnetic shape memory alloy, and the like. A memory alloy, a shape memory polymer, a magnetostrictive material, and an electromagnetic voice coil.

The frictional force control unit is an electroactive polymer. When a voltage is applied to the frictional force control unit, a compressive force is generated and the area is enlarged.

Further, when a voltage is applied to the frictional force control unit, the contact area between the object and the arm may be increased by enlarging the area of the frictional force control unit.

Also, when the contact area is increased, the friction coefficient between the object and the arm is increased, and the frictional force between the object and the arm may be increased due to the increase of the friction coefficient.

According to another aspect of the present invention, there is provided a method of controlling a micro gripper device including an arm and a frictional force control unit, the method comprising: And changing the frictional force between the object and the cancer to grip the object.

The step of gripping the object may further include changing a contact area between the object and the arm, changing a friction coefficient between the object and the arm using the change in the contact area, And changing the friction force between the object and the arm.

In addition, the object may be gripped using at least one of a distance between the object and the arm and a force of the arm pressing the object.

Further, the coefficient of friction may be changed according to the true contact area determined according to the equation. In the above equation,? Is the friction coefficient,? Is the true contact area,? Is the shear stress, and? Is the weight of the object.

The frictional force control unit may include a dielectric elastomer, a conductive polymer, a ferroelectric polymer, an electrostrictive polymer, an ionic polymer / metal composite (IPMC) A piezoelectric ceramic, a piezoelectric polymer, a thermally activated shape memory alloy, a ferromagnetic shape memory alloy, and the like. A memory alloy, a shape memory polymer, a magnetostrictive material, and an electromagnetic voice coil.

The frictional force control unit is an electroactive polymer. When a voltage is applied to the frictional force control unit, a compressive force is generated and the area is enlarged.

The step of gripping the object further includes the steps of applying a voltage to the friction force control unit, increasing a contact area between the object and the arm by enlarging the area of the friction force control unit, And increasing the frictional force between the object and the arm due to the increase of the frictional coefficient.

Meanwhile, a micro gripper device including an arm and a frictional force controller related to an example of the present invention for realizing the above-mentioned problems is provided with a digital processing device to perform a method of gripping an object A method of gripping an object, the method comprising the steps of: supporting the object with the arm; and transmitting the object and arm Wherein the step of gripping the object comprises: changing a contact area between the object and the cancer; calculating a friction coefficient between the object and the cancer using the change in the contact area; Changing the frictional force between the object and the cancer using the change in the friction coefficient It can hamhal.

In addition, the object may be gripped using at least one of a distance between the object and the arm and a force of the arm pressing the object.

Further, the coefficient of friction may be changed according to the true contact area determined according to the equation. In the above equation,? Is the friction coefficient,? Is the true contact area,? Is the shear stress, and? Is the weight of the object.

The present invention can provide a user with a micro gripper that grips an object using a change in friction force.

Specifically, the present invention changes the friction coefficient between the object and the arm or the gripper by using a change in the contact area between the object and the arm or the gripper, and changes the frictional force between the object and the arm or gripper using the change in the friction coefficient, You can provide the user with a micro gripper that grips the object.

It should be understood, however, that the effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present invention belongs It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be construed as limited.
Figure 1 shows a schematic perspective view of a micro gripper according to the prior art.
2A and 2B are schematic cross-sectional views illustrating a method of driving a micro gripper according to the related art.
3 shows an example of a micro gripper that grips an object using a change in friction force, in the context of the present invention.
4 is a flowchart for explaining a specific process in which the micro gripper of the present invention grips an object.
5 is a schematic perspective view illustrating the operation of an electroactive polymer applicable to a gripper in the context of the present invention.
6 is a flow chart for explaining a specific method of manufacturing an electroactive polymer that can be applied to a gripper, in the context of the present invention.
Figures 7A-7E illustrate one example of specific steps for making an electroactive polymer that can be applied to a gripper, in conjunction with the present invention.
8 shows a specific example of a micro gripper to which an electroactive polymer is applied, in the context of the present invention.
Fig. 9 shows a specific example in which a micro gripper to which an electroactive polymer is applied grips an object, in the context of the present invention.
10A to 10C show specific examples of a micro gripper to which an electroactive polymer is applied.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. In addition, the embodiment described below does not unduly limit the content of the present invention described in the claims, and the entire structure described in this embodiment is not necessarily essential as the solution means of the present invention.

Figure 1 shows a schematic perspective view of a micro gripper according to the prior art.

Referring to FIG. 1, the micro gripper 10 comprises a pair of micro gripper structures 11, 12 facing each other.

The micro gripper 10 has an advantage of performing a gripping operation by an actuator to precisely manipulate the micro parts and the bio cell.

In FIG. 1, the actuator is mainly driven by piezoelectric, but the present invention is not limited thereto.

2A and 2B are schematic cross-sectional views illustrating a method of driving the micro gripper according to the related art.

2A, structures of the pair of micro gripper structures 11 and 12 are narrowed by the driving of the actuator, so that the object 20 can be caught.

Thereafter, the gap between the structures (11, 12) of the pair of micro gripper jaws is widened to release the force of holding the object (20).

2B, an electrostatic force is generated between the object 20 and the structures 11 and 12 of the gripper jaw when an object of 100 μm or less is caught by the micro gripper The stiction phenomenon that the object 20 sticks to the structures 11 and 12 of the gripper trough may occur.

Meanwhile, the micro-gripping technique applied to the micro gripper currently controls the gripping operation only through the displacement control or the force control.

However, in order to accomplish the object of the micro gripper described above, a surface roughness control of a micro-gripper tip is additionally required for a finer work, and a solution thereof is required.

Meanwhile, the micro-gripping technique applied to the conventional micro gripper described above controls the gripping operation only through the displacement control or the force control.

However, in order to finer work, additional control of the surface roughness of the micro-gripper tip is required, and a solution thereof is required.

Accordingly, the present invention provides a micro gripper that grips an object using a change in friction force and a control method thereof.

That is, the present invention aims to provide the micro control function of the micro gripper to the user by changing the friction force between the gripper part and the object gripping the object.

3 shows an example of a micro gripper that grips an object using a change in friction force, in the context of the present invention.

3, by varying the frictional force between the object and the portions 31 and 32 connected to the ends of the respective structures 11 and 12 of the pair of micro gripper jaws, Fine gridding can be enabled.

In an embodiment of the present invention, the ends 31 and 32 of each of the pair of micro gripper structures 11 and 12 may be formed of an electroactive polymer.

Electroactive polymer is a polymer which generates compressive force when a voltage is applied and has a wider area, and a detailed description thereof will be given later.

In order to clearly distinguish between the structures 11 and 12 of the pair of micro gripper jaws and the parts 31 and 32 connected to the object, a pair of micro gripper jaws The structures 11 and 12 are referred to as arms 11 and 12 and the ends 31 and 32 are referred to as frictional force control sections 31 and 32, respectively.

Hereinafter, the present invention will be described on the assumption that the present invention includes arms 11 and 12 supporting an object, and frictional force control units 31 and 32 for changing the frictional force between the object and the arm to grip the object. The present invention is not limited thereto, and it is obvious that various methods capable of changing the frictional force between the object and the cancer can be applied.

The frictional force between the object and the arm can be changed according to the following equations (1) and (2).

는 마찰력이고

는 마찰계수이고

는 진실접촉면적이며

는 전단응력이고

는 상기 객체의 무게이다.In equations (1) and (2)

Is the frictional force

Is the coefficient of friction

Is the true contact area

Is the shear stress

Is the weight of the object.

Equation (1) is a formula for expressing the frictional force.

를 구하기 위한 수식을 유도한 것이 수학식 2이다.In Equation 1, the coefficient of friction

(2) " (2) "

는 진실접촉면적

및 전단응력

에 비례하고, 객체의 무게

에 반비례한다는 사실을 확인할 수 있다.Referring to Equation 2, the coefficient of friction

The true contact area

And shear stress

, The weight of the object

And the inverse of the inequality.

및 전단응력

에 따라 변화될 수 있고, 이러한 마찰계수의 변화는 마찰력의 변화를 유도한다.The coefficient of friction is therefore the true contact area

And shear stress

And this change in friction coefficient leads to a change in frictional force.

도 증가되고, 마찰계수가 감소하면, 마찰력

도 함께 감소된다.That is, as shown in Equation (1), when the coefficient of friction increases,

Is increased, and the friction coefficient is decreased, the frictional force

.

및 전단응력

이 변화될 수 있고, 이러한 변화에 대응하여 마찰계수

도 함께 변화되며, 마찰계수

의 변화에 대응하여, 마찰력

를 변화시킴으로써, 객체를 그립하는 방법에 대한 미세 조정이 가능해질 수 있다.Thus, by varying the contact area between the object and the cancer,

And shear stress

Can be changed, and the friction coefficient

And the coefficient of friction

Corresponding to the change of the frictional force

It is possible to fine-tune the method of gripping the object.

Therefore, the micro gripper proposed by the present invention can control the fine gripping operation by changing the frictional force between the object and the arm.

Furthermore, the existing method, that is, the distance between the object and the cancer, and the force of the arm pressing the object, can be additionally used.

By using at least one of a change in the friction between the object and the cancer, a change in the distance between the object and the cancer, and a change in the force pressing the object against the cancer, finer grapping operations are possible.

FIG. 4 is a flowchart for explaining a specific process of gripping an object by the micro gripper of the present invention described above with reference to FIG. 3. FIG.

First, the arms 11 and 12 can support the object 20 (S410).

Thereafter, the contact area between the object 20 and the arms 11 and 12 may be changed (S420).

When the contact area between the object 20 and the arms 11 and 12 changes, the friction coefficient between the object and the arm can be changed using the change in the contact area as described above with reference to Equation 2 (S430) .

Further, the friction force between the object and the cancer is changed as described above with reference to Equation (1) using the change of the friction coefficient (S440).

Accordingly, the friction force between the object and the cancer is changed finally so that the object can be finely gripped (S440).

The frictional force control units 31 and 32 that can be applied to the present invention may be any of a variety of materials such as a dielectric elastomer, a conductive polymer, a ferroelectric polymer, an electrostrictive polymer, an ionic polymer metal polymer Polymer / metal Composites, IPMC, Liquid Crystal Elastomers, Piezoelectric Ceramics, Piezoelectric Single Crystals, Piezoelectric Polymers, Thermally Activated Shape Memory Alloys, , A ferromagnetic shape memory alloy, a shape memory polymer, a magnetostrictive material, and an electromagnetic voice coil.

However, the specific forms of the friction force control sections 31 and 32 are merely one example to which the present invention can be applied, and the present invention is not limited thereto.

Meanwhile, according to another embodiment of the present invention, the friction force control units 31 and 32 may be an electroactive polymer.

When a voltage is applied to an electroactive polymer, a compressive force is generated and the area is widened.

5 is a schematic perspective view illustrating the operation of an electroactive polymer applicable to a gripper in the context of the present invention.

The electroactive polymer shown on the left side of FIG. 5 shows a general form.

5, when a high voltage is applied to the flexible electrodes coated on the upper and lower sides of the general electroactive polymer shown on the left side, as shown in the right side of FIG. 5, the electroactive polymer The compressive force is generated and the area is widened.

Therefore, by applying such a characteristic to the present invention, a finer gripping operation may be performed.

Prior to a specific description of the present invention to which an electroactive polymer is applied, a method for producing an electroactive polymer will be described in detail.

6 is a flow chart for explaining a specific method of manufacturing an electroactive polymer that can be applied to a gripper, in the context of the present invention.

7A to 7E illustrate an example of specific steps for manufacturing an electroactive polymer that can be applied to a gripper in connection with the present invention.

Referring to FIG. 6, a multilayer electroactive polymer may be prepared by observing a polymer dielectric and a flexible electrode (S610).

With respect to step S610, as shown in FIG. 7A, the height of each layer applied to the PDMS in the unilastomer and spin coating of step S610 can be as follows. In step S610, a drying process and a CNT electrodeposition process at a high temperature are performed.

Thereby, as shown in FIG. 7B, a multilayered electroactive polymer (EAP) can be produced.

Next, the electro-active polymer is heated and a metal housing step S620 is performed.

That is, as shown in FIG. 7C, after heating a multilayered electroactive polymer (EAP), a pair of metal housings, which can be housed in a half-wave form, are used to form a circularly twisted electroactive polymer EAP).

Thereafter, the metal-housed electroactive polymer is stretched and attached to the flexible PCB (S630).

That is, as shown in FIG. 7D, the electroactive polymer that has been round-twisted and reduced in step S620 may be stretched and then attached to the flexible PCB.

In addition, a voltage (step S640) may be performed so that the electroactive polymer is returned to its original shape.

That is, as shown in FIG. 7E, when a voltage is applied to an electroactive polymer, a compressive force is generated, and the area in contact with the object is widened.

8 shows a specific example of a micro gripper to which an electroactive polymer is applied, in the context of the present invention.

In FIG. 8, the friction force control units 31 and 32 are composed of the electroactive polymer described above with reference to FIG. 6 and FIGS. 7A to 7E.

9 shows a specific example in which a micro gripper to which an electroactive polymer is applied grips an object, in the context of the present invention.

9, the friction force control units 31 and 32 to which the electroactive polymer is applied and the object 20 are in contact with each other.

At this time, a voltage may be applied to the frictional force control units 31 and 32 in the upper diagram.

Corresponding to this, the area of the frictional force control section in the lower drawing becomes wider on the basis of the material characteristic, and the contact area between the object and the arm is increased.

Also, when the contact area is increased, the friction coefficient between the object and the arm is increased, and the frictional force between the object and the cancer is ultimately increased due to the increase of the friction coefficient.

Therefore, the frictional force change can be further derived based on the material characteristics of the frictional force control units 31 and 32, so that the fine adjustment function of the present invention can be further reinforced.

Meanwhile, according to another embodiment of the present invention, the electroactive polymer described above with reference to FIG. 6 and FIGS. 7A to 7E is flexible and can be mounted on a round surface, have.

10A to 10C show specific examples of the friction force control units 31 and 32 to which the electroactive polymer is applied.

10A to 10C, there is shown a specific example of the friction force control units 31 and 32 to which the electroactive polymer mounted on the upper end of the rounded arm 12 is applied.

10A to 10C, only one arm 12 is shown, but it is obvious that the frictional force control portions 31 and 32 may be included in the other arm 11 constituting a pair.

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission over the Internet) . In addition, the computer-readable recording medium may be distributed over network-connected computer systems so that computer readable codes can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers of the technical field to which the present invention belongs.

It should be noted that the above-described apparatus and method are not limited to the configurations and methods of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments are selectively combined .

Claims (18)

1. A micro gripper device for gripping an object,
An arm supporting the object; And
And a friction control unit for controlling the grip of the object by changing a friction force between the object and the arm,
Wherein the frictional force control unit changes the frictional coefficient between the object and the arm using a change in the contact area and controls the frictional force between the object and the cancer to change using the change in the frictional coefficient,
Wherein the coefficient of friction is changed according to a true contact area determined according to the following equation: < EMI ID = 1.0 >
Equation

In the above equation

Is the coefficient of friction

Is the true contact area

Is the shear stress

Is the weight of the object. delete The method according to claim 1,
Wherein the frictional force control unit controls at least one of a distance between the object and the arm and a force of the arm pressing the object. delete The method according to claim 1,
The frictional force control unit may be formed of a polymer material such as a dielectric elastomer, a conductive polymer, a ferroelectric polymer, an electrostrictive polymer, an ionic polymer / metal composite (IPMC) A piezoelectric ceramic, a piezoelectric polymer, a thermally activated shape memory alloy, a ferromagnetic shape memory alloy (hereinafter, referred to as " ferromagnetic shape memory alloy "), a dielectric ceramic, Wherein the micro gripper device is configured by a combination of at least one of an electromagnetic coil, an alloy, a shape memory polymer, a magnetostrictive material, and an electromagnetic voice coil. The method according to claim 1,
The frictional force control unit is an electroactive polymer,
Wherein when a voltage is applied to the frictional force control unit, a compressive force is generated and the area is widened. The method according to claim 6,
When a voltage is applied to the frictional force control unit,
Wherein the contact area between the object and the arm is increased by enlarging the area of the frictional force control unit. 8. The method of claim 7,
When the contact area is increased, the friction coefficient between the object and the arm is increased,
Wherein the frictional force between the object and the arm is increased due to the increase of the coefficient of friction. A method of controlling a micro gripper device including an arm and a frictional force control part,
Supporting the arm with the object; And
And changing the friction force between the object and the arm to grip the object,
Wherein the step of gripping the object comprises:
Changing a contact area between the object and the cancer;
Changing a coefficient of friction between the object and the arm using the change in the contact area; And
And changing the frictional force between the object and the cancer using the change in the friction coefficient,
Wherein the coefficient of friction is changed according to a true contact area determined according to the following equation.
Equation

In the above equation

Is the coefficient of friction

Is the true contact area

Is the shear stress

Is the weight of the object. delete 10. The method of claim 9,
Wherein the object is gripped using at least one of a distance between the object and the arm and a force of the arm pressing the object. delete 10. The method of claim 9,
The frictional force control unit may be formed of a polymer material such as a dielectric elastomer, a conductive polymer, a ferroelectric polymer, an electrostrictive polymer, an ionic polymer / metal composite (IPMC) A piezoelectric ceramic, a piezoelectric polymer, a thermally activated shape memory alloy, a ferromagnetic shape memory alloy (hereinafter, referred to as " ferromagnetic shape memory alloy "), a dielectric ceramic, Wherein the micro gripper device comprises a combination of at least one of Alloy, Shape Memory Polymer, Magnetostrictive material and Electromagnetic voice coil. 10. The method of claim 9,
The frictional force control unit is an electroactive polymer,
Wherein when a voltage is applied to the frictional force control unit, a compressive force is generated and the area is widened. 15. The method of claim 14,
Wherein the step of gripping the object comprises:
Applying a voltage to the frictional force control unit;
Increasing a contact area between the object and the arm by enlarging the area of the frictional force control unit;
Increasing the friction coefficient between the object and the arm due to the increase in the contact area; And
Further comprising increasing the frictional force between the object and the arm due to an increase in the coefficient of friction. A program of instructions executable by a digital processing device is tangibly embodied to perform a method of gripping an object by a micro gripper device including an arm and a frictional force control, A recording medium readable by a processing apparatus,
A method for gripping an object,
Supporting the object by the arm; And
And changing the friction force between the object and the arm to grip the object,
Wherein the step of gripping the object comprises:
Changing a contact area between the object and the cancer;
Changing a coefficient of friction between the object and the arm using the change in the contact area; And
And changing a frictional force between the object and the cancer using the change in the friction coefficient,
Wherein the friction coefficient is changed according to a true contact area determined according to the following equation.
Equation

In the above equation

Is the coefficient of friction

Is the true contact area

Is the shear stress

Is the weight of the object. 17. The method of claim 16,
Wherein the object is gripped using at least one of a distance between the object and the arm and a force of the arm pressing the object. delete

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