KR20160072428A - Dual-mode active gear-shifting twisted string actuator and robot finger having the same - Google Patents

Abstract

The present invention relates to a dual-mode active gear-shifting twisted string actuator capable of supplementing weakness for the dual-mode active gear-shifting twisted string actuator, and having an improved structure to accurately control a position and change of speed. According to an embodiment of the present invention, the dual-mode active gear-shifting twisted string actuator comprises: a first driving unit including a rotating output shaft; a first coupler including a shaft mounted on the outlet shaft of the first driving unit, rotating in accordance with a rotation of the output shaft; a second coupler including a shaft accommodating unit connected such that the shaft performs idle rotation, and at least two string accommodating units; a second driving unit limiting the rotation of the second coupler at a predetermined range, and applying additional rotating force to the second coupler to rotate out of the predetermined range; a power transfer unit transferring power between the second coupler and the second driving unit; and at least two string members having one end fixated to the first coupler and an other end fixated to a mover side, arranged to pass through the string accommodating unit of the second coupler.

Description

[0001] The present invention relates to a dual mode active shift line twist actuator and a robot finger having the dual mode active gear-shifting twisted string actuator and robot finger having the same.

More particularly, the present invention relates to an actuator using a twisted-pair drive principle, and more particularly, by adding a small clutch motor to a main actuator, it is possible to perform autonomous mode switching with a simple structure, And more particularly, to a dual mode active speed line twist actuator and a robot finger having the dual mode active speed line twist actuator.

 Generally, robots are widely used in various applications such as industrial, surgical, and military applications. Actuator is an essential element for realizing the motion of the robot, and among the various actuators, the motor is most used for the robot. The motor is used mainly as a power source for rotating a wheel of a mobile robot moving by rotating the wheel, or when moving a joint of a manipulator or the like. At this time, if the method of driving by the motor and the gear is implemented without special mechanism, since the motor torque and the speed are fixed, it is difficult to obtain the performance of the robot desired by most developers and users. Therefore, if the performance of the actuator itself can not solve this problem, a special mechanism is required to satisfy the required performance depending on the application field and the intended use of the robot.

 A special mechanism such as that described above is a twisted-pair drive mechanism (Thomas W. urtz, Chris May, Benedikt Holz, C. Natale, G. Palli and C. Melchiorri, "The Twisted String Actuation System: Modeling and Control, "2010 IEEE / ASME International Conference on Advanced Intelligent Mechatronics, pp. 121-5-1220). In addition, a patent for the development of an actuator using a twisted-pair driving mechanism (Murata et al, Actuator, Pub. No. US2008 / 0066574 A1) and a patent for precise position control through a twisted- actuator, Pub. No. US2008 / 0077258 A1).

However, the above-mentioned line twisting drive mechanisms have an advantage that a large linear driving force can be obtained even with a small output motor, but there is a disadvantage that the linear driving speed for driving the robot etc. is slow.

Robots in various fields currently being developed require both large driving force and fast driving speed. However, due to the limitations of the performance of the actuator, robots are developed in a way that the drive force and the drive speed are traded off by the designer depending on the purpose or use of the robot, and as a result, satisfactory performance There is a problem that the robot can not be developed.

 To solve this problem, a dual-mode line-twist actuator using a twisted twist and a two-speed transmission mechanism (Kim Kyung Su, Kim Soo Hyun, Shin Young Joon, Dual Mode Line Twist Actuator, Application No. 2011-0030664) , It is possible to generate a high speed or to generate a large driving force.

However, the dual-mode twisted-pair actuator also has a serious disadvantage to the transmission mechanism, which is difficult to use in practice.

Korean Patent No. 10-1261986 (2013.05.02.) U.S. Published Patent Application US2008 / 0077258A1 (Mar. 27, 2008) US Published Patent US2008 / 0066574A1 (Mar. 20, 2008)

SUMMARY OF THE INVENTION The present invention provides a dual mode active speed line twist actuator with improved structure to compensate for the disadvantages of dual mode line twist actuators and to enable shifting and accurate position control.

The dual mode active speed line twist actuator according to the present embodiment includes a first driving unit including a rotating output shaft; A first coupler mounted on an output shaft of the first driving unit and rotating according to rotation of the output shaft and including a shaft; A shaft receiving portion connected to rotate the shaft idle, and a second coupler including at least two row receiving portions; A second driver for restricting rotation of the second coupler within a predetermined range and adding an additional rotational force to the second coupler so as to rotate the second coupler outside the predetermined range; A power transmission unit for transmitting power between the second coupler and the second drive unit; And at least two string members fixed at one end to the first coupler and at the other end to the mover, and arranged to penetrate the string receiving portion of the second coupler.

The power transmission portion includes a first gear portion formed on an outer circumferential surface of the second coupler; And a second gear portion disposed on an output shaft of the second driving portion.

The second drive may be either a clutch or an additional power transmission mechanism.

The second driving unit imparts a torque to the second coupler and induces a difference in rotational speed between the first coupler and the second coupler under the control of the second driving unit to control the speed mode and the force mode Drive switching may be possible.

The second driving unit may further include a rotation sensor unit that senses the rotation speed. The rotation speed of the second coupler may be measured when the first and second couplers are operated in the speed mode and the force mode in conjunction with the rotation speed of the second coupler .

The power consumption of the second driver may be smaller than that of the first driver.

When the second driving unit is constituted of an electric motor, a minimum torque and a no load speed of the second driving unit capable of operating the speed mode and the force mode when the force of the T is applied to the mover ) Can satisfy the following equation.

In the speed mode, M _m2 is the continuous torque of the second driving unit, n _m1 is the no-load rotational speed of the first driving unit, n _m2 is the no-load rotational speed of the second driving unit, applied to the mover attached to the force, α _I is the angle of the cold chamber to the shaft, α _ⅱ the line angle between the twisted yarn, K _l1 is the gear ratio, K _l2 coupled between the first coupler and the first drive unit And a gear ratio between the second coupler and the second driving unit.

A robot finger according to the present embodiment includes an actuator, a first link; A robot finger rotatably connected to the first link by at least one joint and controlled by the actuator, the robot finger comprising: a first driver including a rotating output shaft; A first coupler mounted on an output shaft of the first driving unit and rotating according to rotation of the output shaft and including a shaft; A shaft receiving portion connected to rotate the shaft idle, and a second coupler including at least two row receiving portions; A second driver for restricting rotation of the second coupler within a predetermined range and adding an additional rotational force to the second coupler so as to rotate the second coupler outside the predetermined range; A power transmission unit for transmitting power between the second coupler and the second drive unit; And at least two string members fixed at one end to the first coupler and at the other end to the mover and disposed to penetrate the line receiving portion of the second coupler, And may include at least two ropes attached to receive the rotational force of the second coupler and extending beyond the line receiving portion of the second coupler and the other end fixed to the controlled link.

According to the present embodiment as described above, it is possible to improve the disadvantage of the conventional dual-mode twist-angle actuator, which is inconsistent at the time of shifting, can not perform shifting at a desired point and requires a complicated releasing process, It is possible to actively shift between the speed mode and the force mode and simplify the looping process. Thus, it is possible to solve the disadvantages while maintaining the advantages of the conventional dual mode twisted-pair actuator.

In addition, since the power consumption of the clutch motor for shifting requires a very small amount of power compared with the main driver, the use of a small clutch motor can be effectively applied to a very small mechanical device such as a robot hand.

Also, the conventional modeling method has a large error of about 62% when compared with the displacement of the actual mover, but the modeling method according to the present embodiment has a small error of about 5.07%. Therefore, accurate open loop control without sensor is possible, and optimized specification of main driver and clutch motor can be determined through simulation in motor selection process to obtain desired output.

1 is a schematic diagram of a dual mode active speed line twist actuator according to this embodiment,
Fig. 2 schematically shows the twisted shape of the speed mode, Fig.
Fig. 3 schematically shows the line twisted shape of the force mode, Fig.
FIG. 4 is a graph showing a comparison between a conventional modeling and a mover displacement according to the present embodiment,
5 and 6 schematically illustrate the active shifting process of the speed mode and the force mode,
7 is a diagram showing a lane-releasing process of the dual-mode active transmission mechanism,
8 is a graph showing an implementation process of a speed mode and a force mode,
FIG. 9 is a view showing a free object in the force mode, and FIG.
10 and 11 are views showing a robot finger to which the dual mode active transmission actuator according to the present embodiment is applied.

Hereinafter, a dual mode active speed line twist actuator according to the present embodiment will be described with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

In addition, the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. For convenience of explanation, the size and shape of each constituent member shown may be exaggerated or reduced have.

On the other hand, terms including an ordinal number such as a first or a second may be used to describe various elements, but the constituent elements are not limited by the terms, and the terms may refer to a constituent element from another constituent element It is used only for the purpose of discrimination.

FIG. 1 is a schematic diagram of a dual mode active speed line twist actuator according to the present embodiment, FIG. 2 is a view schematically showing a line twisted shape of a speed mode, and FIG. 3 is a view schematically showing a line twisted shape of a force mode 5 and 6 are views schematically showing an active shifting process of a speed mode and a force mode, FIG. 7 is a diagram showing a dual mode active FIG. 8 is a graph showing an implementation process of a speed mode and a force mode, FIG. 9 is a view showing a free body diagram in the force mode, and FIGS. 10 and 11 are views 1 is a view showing a robot finger to which a dual mode active transmission actuator according to an embodiment is applied.

1, the dual mode active speed line twist actuator includes a first driving unit 2, a first coupler 10, a second coupler 20, and a second driving unit 23 can do.

The first driving unit 2 may be a motor, and the first coupler 10 may be connected to the output shaft 1. The first driving unit 2 can rotate the first coupler 10 forward or reverse using the rotational power.

The first coupler 10 may be provided in a disc shape and may be installed to be rotatable in the forward or reverse direction in conjunction with the output shaft 1. The first coupler 10 may be provided in a substantially disc shape, and a first string member 110 may be connected to one end of the first coupler 10. The first jig member 110 may be fixed to the surface of the first coupler 10 and one end thereof may be inserted and fixed in the first coupler 10. A shaft 15 may be connected to the center of the first coupler 10. The shaft 15 may be disposed coaxially with the first coupler 10 and may be formed in a cylindrical shape having a diameter smaller than that of the first coupler 10. At this time, the shaft 15 rotates in conjunction with the first coupler 10, and the first string member 110 can be wound on the outer peripheral surface of the shaft 15 by the rotation of the first coupler 10.

At this time, the first string members 110 may be arranged in pairs so that they are symmetrical with respect to the center of the first coupler 10. That is, the first string member 110 is disposed on an imaginary line passing through the center of the first coupler 10, and a pair of first string members 110 are arranged such that the distance from the center is the same . Accordingly, as shown in FIG. 1, when the shaft 15 and the first coupler 10 rotate together, the first string member 110 can be wound around the outer circumferential surface of the shaft 15.

The second coupler 20 can be coupled to the shaft 15 according to the present embodiment, and the second coupler 20 and the shaft 15 can be idly coupled. To this end, the second coupler 20 may be provided with a shaft receiving portion in a shape corresponding to the shaft 15. Accordingly, the second coupler 20 does not rotate in conjunction with the rotation of the shaft 15, but can be rotated separately from the shaft 15 by receiving the power of the second driving unit 23, which will be described later. The shaft receiving portion may be configured in various ways. That is, the shaft 15 and the second coupler 20 may be configured so as not to be rotatably interlocked with each other through a bearing or the like not shown, and a lubricating gel or the like may be applied to the shaft 15, (Not shown).

The second coupler 20 may be provided with at least one line accommodating portion 20a. At this time, the line accommodating portion 20a may be formed in a circular shape, So that it can be connected to the second string member 120 side. That is, when the first and second string members 110 and 120 are integrally formed, the string member may be passed through the string receiving portion 20a and the end portion may be connected to the mover 30.

The second driving unit 23 may limit the rotation of the second coupler 20 within a predetermined range and may apply additional rotational force to the second coupler 20 so that the second coupler 20 can rotate outside the predetermined range. The second drive unit 23 may be configured in various ways, and may be a conventional motor, or an additional power transmission mechanism including a clutch.

Meanwhile, the power of the second drive unit 23 may be transmitted to the second coupler 20 through the power transmission unit. According to the present embodiment, the power transmitting portion may be constituted by the first and second gear portions 21 and 22.

The first gear portion 21 may be formed on the outer circumferential surface of the second coupler and the second gear portion 22 may be formed to mate with the first gear portion 21, Can be connected to the output shaft. At this time, the first and second gear portions 21 and 22 may be formed to have a predetermined gear ratio, which may vary according to the required power magnitude.

The second drive unit 23 can apply torque to the second coupler 20 and adjust the rotation of the second coupler 20 by controlling the rotation of the second drive unit 23 have. The rotation speed difference between the first coupler and the second coupler causes the first jig member to be wound on the shaft 15 to cause a speed mode of the mover 30 to be fast, The second string member is caused to be twisted by itself to induce a strong force mode, so that the drive between the modes can be switched.

Although not shown, the second drive unit 23 further includes a rotation sensor unit that senses the rotation speed. The second drive unit 23 may include a rotation sensor unit for detecting the rotation speed of the first and second couplers 20, The number of revolutions of the second coupler 20 can be measured.

Further, the power consumption of the second driving unit 23 may be smaller than that of the first driving unit 2.

When the second driving unit 23 is constructed of an electric motor, a continuous torque of the second driving unit 23 capable of operating the speed mode and the force mode when the force of T is applied to the mover 30, And no load speed can satisfy the following equation.

Here, M _m2 is the continuous torque of the second drive unit 23, n _m1 is the no-load rotation speed of the first drive unit 2, n _m2 is the no-load rotation of the second drive unit 23, T is the force applied to the mover 30 connected to the strand member in the speed mode, the angle of the first strand member 110 wound on the shaft 15,? _II is the angle between the second strand members 120 angle of the twisted line, K _m1 is the gear ratio is connected between the first coupler 10 and the first driving unit (2) gear ratio is connected between the K _m2 is the second coupler 20 and the second driving unit 23 .

Hereinafter, the operation of the dual mode active speed line twist actuator according to the present embodiment will be described with reference to the drawings.

The basic operation of the dual mode active speed line twist actuator according to the present embodiment is similar to the operation of the dual mode line twist actuator of the prior art. That is, when the first coupler 10 rotates, the pair of first string members 110 are wound on the shaft 15. At this time, when an external tension is applied to the first string member 110, the torque applied to the second coupler 20 increases, and the generated torque restricts the rotation of the second coupler 20 When the frictional force of the first and second gears 21 and 22 is exceeded, the second coupler 20 rotates and the yarn between the second coupler 20 and the mover 30 is twisted, As described above, a large force can be generated. Since only the shifting condition using the friction force such as the brake shoe is used for the second coupler 20 in the past, the shifting condition is inconsistent and the shifting can not be performed at a desired time point. In addition, since the second coupler 20 receives the frictional force during the unlocking process due to the brake shoe, the unlocking process is complicated, the control is complicated, and the response time is slow.

However, according to the present embodiment, the second drive unit 23 may be provided as a clutch motor to solve all of the above problems. That is, as described above, the first gear portion 21 is formed on the outer circumferential surface of the second coupler 20, the second gear portion 22 is provided on the output shaft side of the second drive portion 23, The output of the clutch motor constituting the first drive section 23 can be set smaller than the output of the motor of the first drive section 2. [

At this time, the first coupler 10 and the shaft 15 may be integrally formed so as to rotate together. Depending on the magnitude of the torque applied to the second coupler 20, And can be controlled to operate in a speed mode or a force mode.

The driving principle of the dual-mode active transmission mechanism thus constructed is as follows. First, the first coupler 10 is rotated by the power of the first driving unit 2. [ At this time, if the second coupler 20 is kept stationary by the first driving unit 2 provided with the clutch motor, the two strands are wound on the shaft 15, and the mover 30, The speed mode that operates at high speed is activated. Here, when a large force is required to the mover 30, the speed of the second coupler 20 is made equal to the speed of the first coupler 10 through the speed control of the first drive unit 2 provided by the clutch motor , The two strands can be twisted together, and the force mode is activated through this control.

Also, the moving distance of the mover 30 due to the rotation of the first coupler 10 and the second coupler 20 is induced through the geometric shape in which the threads are twisted in the speed mode and the force mode. That is, the yarn twist in the speed mode can be divided immediately before and after the yarn comes into contact with the shaft as shown in the first figure of Fig. 2, and the distance of the yarn mover caused by the twist before the yarn touches the shaft 15 The following equation can be satisfied.

The ΔL _I is the displacement of the mover 30 by the yarn twist of the speed mode, R is a shaft (15) center axis and the first line member 110, the distance to the center, r is the shaft 15, the radial length, θ _l refers to the length of the first coupler (10) angle of rotation, θ _L is the second coupler 20, the rotational angle, x is the x-axis length when the unpacked twisted yarn in a plane, l is the shaft 15 of the .

The distance of the mover after the twist occurs can be derived by the following equations as shown in the second figure of FIG.

That is, the yarn twist in the force mode can be derived by the following equation in consideration of the geometry of the dual mode as shown in FIG.

Where ΔL _II is the displacement of the mover due to thread twist in force mode, l _o is the measured value of l _{w in} the initial state, and r _s is the radius of the thread. Therefore, the displacement of the total mover by the speed mode and the force mode,

. ≪ / RTI >

10 and 11 are views showing a robot finger to which a dual mode active transmission mechanism is applied. A dual mode drive mechanism is applied to the zero link 1001 and the first to third links 1100, 1200 and 1300 are connected to the rotatable link member, The motion of the robot finger can be realized. However, since the dual-mode active transmission mechanism is only capable of unidirectional motion, in order to realize the unloading operation of the robot finger, the spring 1002 is connected to the chamber 1005 connected to the opposite side of the third link 1300, , And maintain a constant tension.

According to the present embodiment as described above, when performing a fast hand movement through an active shift process according to a situation, the robot operates in the speed mode described above. When the robot is strongly held in the force mode, You can develop hands.

Particularly, it is possible to solve the problem that a disadvantage of the conventional dual-mode twist-angle actuator is inconsistent at the time of shifting, a shift can not be performed at a desired time, and a complicated unwinding process is required. In other words, active shifting between speed mode and force mode is possible through the control of clutch motor, and it is possible to simplify the line-up process, which is a disadvantage of maintaining the advantages of the existing dual-mode line-twisting actuator Can be solved.

In addition, since the power consumption of the clutch motor for shifting requires a very small amount of power compared with the main driver, the use of a small clutch motor can be effectively applied to a very small mechanical device such as a robot hand.

Also, the conventional modeling method has a large error of about 62% when compared with the displacement of the actual mover, but the modeling method according to the present embodiment has a small error of about 5.07%. Therefore, accurate open loop control without sensor is possible, and optimized specification of main driver and clutch motor can be determined through simulation in motor selection process to obtain desired output.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the following claims.

One; Output shaft 2; The first driving unit
10; A first coupler 15; shaft
20; A second coupler 20a; The line accommodating portion
21; A first gear portion 22; The second gear portion
23; A second driving unit 30; Mover

Claims (8)

A first driving unit including a rotating output shaft;
A first coupler mounted on an output shaft of the first driving unit and rotating according to rotation of the output shaft and including a shaft;
A shaft receiving portion connected to rotate the shaft idle, and a second coupler including at least two row receiving portions;
A second driver for restricting rotation of the second coupler within a predetermined range and adding an additional rotational force to the second coupler so as to rotate the second coupler outside the predetermined range;
A power transmission unit for transmitting power between the second coupler and the second drive unit; And
And at least two string members, one end of which is fixed to the first coupler and the other end is fixed to the mover, and which is arranged to penetrate the line receiving portion of the second coupler. The power transmission unit according to claim 1,
A first gear portion formed on an outer circumferential surface of the second coupler; And
And a second gear portion disposed on an output shaft of the second driving portion. 3. The method according to any one of claims 1 to 3,
Wherein the second drive is one of a clutch and an additional power transmission mechanism. 3. The apparatus of claim 2, wherein the second driver comprises:
And a second gear coupled to the first gear and the second gear, the second gear coupled to the first gear and the second gear to rotate the second gear, Mode Active Transmission Rope Twist Actuator. 3. The apparatus of claim 2, wherein the second driver comprises:
A dual mode active speed line twist actuator for measuring the number of revolutions of the second coupler when operating in a speed mode and a force mode in conjunction with the rotational speed of the second coupler, . The method according to claim 1,
Wherein a power consumption of the second driving unit is smaller than that of the first driving unit. The method according to claim 1,
The displacement of the mover according to the rotation of the first and second couplers is calculated by using the slope change due to the contact of the stem member of the shaft, the distance between the section passing through the second coupler and the center, Lt; RTI ID = 0.0 > a < / RTI > dual-mode active speed line twist actuator.
The ΔL _I displacement of the mover 30 by twisted twist in the speed mode

In the range of

Lt; / RTI >

Within the phosphorus range,

The ΔL _I is displaced, R is the distance to the shaft 15 the center axis of the first bar member 110, the center, r is the shaft 15, the radial length, θ _I of the mover 30 by the yarn twist of the speed mode, Axis represents the rotation angle of the first coupler 10,? _II represents the rotation angle of the second coupler 20, x represents the x-axis length when the twisted yarn is unwound on the plane, and 1 represents the length of the shaft 15 .
In the force mode, displacement of the mover by the line twist ΔL _II

l _o is the measured value of l _{w in} the initial state, and r _s is the radius of the seal.
At this time, the displacement DELTA L of the total mover 30

An actuator;
A first link,
The robot finger comprising at least one controlled link rotatably connected to the first link by at least one joint and controlled by the actuator,
The actuator includes:
A first driving unit including a rotating output shaft;
A first coupler mounted on an output shaft of the first driving unit and rotating according to rotation of the output shaft and including a shaft;
A shaft receiving portion connected to rotate the shaft idle, and a second coupler including at least two row receiving portions;
A second driver for restricting rotation of the second coupler within a predetermined range and adding an additional rotational force to the second coupler so as to rotate the second coupler outside the predetermined range;
A power transmission unit for transmitting power between the second coupler and the second drive unit; And
And at least two string members fixed at one end to the first coupler and at the other end to the mover and disposed so as to penetrate the line receiving portion of the second coupler,
Wherein the robot finger comprises:
A dual mode active speed line kink control comprising at least two strings attached at one end to receive the rotational force of the first coupler and extending beyond the line receiving portion of the second coupler to secure the other end to the controlled link Robot finger.

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