KR20220059261A - Actuator of stimulating tactile sensation and kinesthesia using porous magnetorheological elastomer - Google Patents

Abstract

The present invention relates to an actuator for stimulating tactile sensation and kinesthesia based on porous magnetorheological elastomer. An actuator according to the present invention comprises: a magnetic field generation unit installed within a housing; porous magnetorheological elastomer installed at the upper part of the magnetic generation unit; and a cover disposed at the upper part of the porous magnetorheological elastomer. The present invention can provide various kinds of kinesthesia as well as tactile sensation to a user by properly adjusting strength of a magnetic field to change robustness and volume of the porous magnetorheological elastomer. In addition, the present invention can generate various vibrations due to contraction and recovery of the porous magnetorheological elastomer by turning on/off the magnetic field with proper frequency and therethrough provide vibration based tactile sensation to the user. In addition, the actuator according to the present invention can be easily applied to a portable device or a small game device because of providing the tactile sensation and the kinesthesia to the user with a simple configuration.

Description

Actuator of stimulating tactile sensation and kinesthesia using porous magnetorheological elastomer

The present invention relates to a haptic actuator capable of stimulating a user's tactile and kinesthetic senses, and more particularly, to an actuator that provides various stimuli to a user using a porous magnetorheological elastomer.

Recently, most portable electronic devices, virtual reality (VR) devices, game machines, simulation devices, etc. have installed haptic actuators to provide various and vivid haptic feedback to users.

There are many different types of haptic actuators, such as Eccentric Rotating Mass (ERM), Linear Resonant Actuator (LRA), piezo element actuator, Electroactive polymer (EAP) actuator, etc. This is widely known.

Meanwhile, haptic feedback can be divided into tactile feedback felt when the user's skin touches an object and kinesthetic feedback felt when joint and muscle movements are disturbed.

However, since most conventional actuators provide a sense of vibration or texture to the user by vibrating the housing or surface, it is difficult to provide the user with a kinesthetic sense (reverse sense).

Although kinesthesia generators are widely used in aviation simulation equipment and medical/industrial manipulators, they cannot be applied to small devices such as portable electronic devices and game machines because most of these devices use motors. There are limits.

Therefore, there is a need to develop a haptic actuator capable of providing a kinesthetic sense to the user in addition to touch while having a simpler configuration.

Publication No. 10-2020-0093103 (published on Aug. 5, 2020)

The present invention was devised against this background, and an object of the present invention is to provide an actuator using a magnetorheological elastomer so that a user can feel various kinesthetic sensations (reverse sense) as well as tactile sensation.

In order to achieve this object, an aspect of the present invention, a magnetic field generator installed inside the housing; A porous magnetorheological elastomer installed on the upper portion of the magnetic field generator; It provides a skin sensory and kinesthetic stimulation actuator comprising a cover disposed on an upper portion of a porous magnetorheological elastomer.

In the actuator according to an aspect of the present invention, the porous magnetorheological elastomer may contain a silicone rubber material, silicone oil, and carbonyl iron in a weight ratio of 1: (0.6 to 0.8): (6 to 8), respectively.

Also, in the actuator according to an aspect of the present invention, a porous magnetorheological elastomer without pores may be installed between the cover and the porous magnetorheological elastomer.

In addition, in the actuator according to an aspect of the present invention, at least one of the porous magnetorheological elastomer and the porous magnetorheological elastomer may have an uneven surface formed thereon.

In addition, in the actuator according to an aspect of the present invention, a low-density porous magnetorheological elastomer having a smaller content of pores compared to the porous magneto-rheoelastic body may be installed between the cover and the porous magneto-rheological elastomer.

In addition, the actuator according to an aspect of the present invention includes a pressure sensor for detecting a force pressed by a user, and when the measured value of the pressure sensor falls within a first set range, a first current is supplied to the magnetic field generator and a second current greater than the first current may be supplied to the magnetic field generator when the measured value of the pressure sensor falls within a second set range greater than the first set range.

In addition, the actuator according to an aspect of the present invention includes a pressure sensor for detecting a force that a user presses, and when the measured value of the pressure sensor falls within a first set range, the first current is applied to the magnetic field generator A second current smaller than the first current may be supplied to the magnetic field generator when the measured value of the pressure sensor falls within a second set range greater than the first set range.

In addition, the actuator according to an aspect of the present invention includes a pressure sensor for detecting a force that a user presses, and when the measured value of the pressure sensor falls within a first set range, the magnetic field generator is turned on/off at a first frequency. is turned off, and when the measured value of the pressure sensor falls within a second set range greater than the first set range, the magnetic field generator may be turned on/off at a second frequency different from the first frequency.

In addition, in the actuator according to an aspect of the present invention, a guide groove into which the upper end of the side wall of the housing is inserted is formed on the edge of the bottom surface of the cover, and a blocking protrusion having a width greater than the entrance of the guide groove is formed on the side wall of the housing. can

According to the present invention, by appropriately adjusting the strength of the magnetic field to change the stiffness and volume of the porous magnetorheological elastomer, it is possible to provide various kinesthetic sensations as well as tactile sensations to the user. In addition, by turning the magnetic field on/off at an appropriate frequency, various vibrations can be generated by the contraction and restoration of the magnetorheological elastomer, and through this, a vibration-based tactile sensation can be provided to the user.

In addition, the actuator according to the present invention has an advantage that it can be easily applied to a portable device or a small game machine because it can provide a user with a tactile sense and a kinesthetic sense with a simple configuration.

1 is a perspective view of an actuator according to a first embodiment of the present invention;
2 is an exploded perspective view of an actuator according to a first embodiment of the present invention;
3 is an exploded cross-sectional view of an actuator according to a first embodiment of the present invention;
4 is a view illustrating a coupling structure of a housing and a cover;
5 is a diagram for preparing the displacement of the porous magnetorheological elastomer according to the presence or absence of a magnetic field;
6 is a view showing the vibration principle of the actuator according to the first embodiment of the present invention;
7 is a flowchart showing a method of manufacturing a porous magnetorheological elastomer;
8 is a diagram showing the difference in porosity according to the ethanol content
9 is a view showing the difference in pressure resistance according to the degree of porosity;
10 is a cross-sectional view of an actuator according to a second embodiment of the present invention;
11 is a cross-sectional view showing a modified example of the actuator according to the second embodiment of the present invention;
12 is a cross-sectional view of an actuator according to a third embodiment of the present invention;
13 is a cross-sectional view of an actuator according to a fourth embodiment of the present invention;
14 to 16 are cross-sectional views showing various modifications of the actuator according to the embodiment of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

For reference, in the drawings attached to the present specification, there are parts indicated with dimensions or ratios different from those of actuality, but this is for convenience of explanation and understanding. In addition, in the present specification, when one element is connected, coupled or electrically connected to another element, it is not only directly connected, combined, or electrically connected to another element, but also when another element is interposed in between. and indirectly connected, coupled, or electrically connected to each other. In addition, when one element is directly connected or combined with another element, it means that it is connected or combined without another element in the middle. In addition, the inclusion of a certain component in a certain part means that other components may be further included, rather than excluding other components, unless otherwise specifically stated. Also, in the present specification, expressions such as before, after, left, right, up, and below are relative concepts that may vary depending on the viewing position, and thus the scope of the present invention should not be necessarily limited to the corresponding expressions.

<First embodiment>

As shown in the perspective view of FIG. 1 , the exploded perspective view of FIG. 2 and the cross-sectional view of FIG. 3 , the actuator 100 according to the first embodiment of the present invention includes a housing 110 surrounding an internal space, installed inside the housing. The magnetic field generating unit 120 , the porous magnetorheological elastomer 130 disposed on the magnetic field generating unit 120 , and the edge are coupled to the upper end of the housing 110 in a state in which the bottom surface is in contact with the porous magnetorheological elastomer 130 . It includes a cover 140 that is.

The housing 110 preferably serves to block external magnetic fields or noise while protecting internal components. For this, it is preferable to use the housing 110 made of a magnetic material.

When the housing 110 made of a magnetic material is used, the magnetic field lines generated by the magnetic field generating unit 120 inside are guided along the bottom and sidewalls of the housing 110, so that the loss of the magnetic field can be minimized and the influence of external magnetic fields or noise can be minimized. can

However, when a separate magnetic material surrounding the porous magnetorheological elastomer 130 is installed inside the housing 110 , the housing 110 may be manufactured using a non-magnetic material such as plastic.

The cover 140 serves as a medium that directly or indirectly transmits the deformation or vibration of the porous magnetorheological elastomer 130 positioned below to the user. Like the housing 110 , the cover 140 is preferably made of a magnetic material capable of inducing magnetic force lines.

The bottom surface of the cover 140 is preferably in contact with the upper surface of the porous magnetorheological elastomer 130 , and in some cases, may be adhered to the upper surface of the porous magnetorheological elastomer 130 using an adhesive or the like.

The cover 140 has to move up and down with respect to the housing 110 when the porous magnetorheological elastomer 130 deforms or vibrates. A guide groove 142 may be formed.

In this case, in order to prevent the upper end of the side wall of the housing 110 from falling out while being inserted into the guide groove 142 of the cover 140 , as shown in FIG. 4 , the side wall of the housing 110 has one or both sides protruding. A locking protrusion 112 may be formed, and a locking protrusion 144 may be formed on the inner wall of the entrance of the guide groove 142 to prevent the inserted locking projection 112 from falling out.

In order to couple the cover 140 to the upper end of the housing 110 , in a state where the guide groove 142 of the cover 140 is positioned on the upper side of the side wall of the housing 110 , the locking protrusion 112 passes through the narrow entrance and the locking jaw (144) can be combined by applying strong pressure to the press fit type so that it can reach the upper part.

Meanwhile, the cover 140 may be disposed on the surface of a controller held by the user, or may be disposed under the surface.

The magnetic field generator 120 includes a core 124 and a coil 122 wound around the core 124 , and the coil 122 is connected to a power source (such as a battery) through a switching means. When a current is applied to the coil 122, a magnetic field passing through the core 124, the cover 140, and the housing 110 is generated as shown in FIG. stiffness will change.

In particular, since the rigidity of the porous magnetorheological elastomer 130 varies according to the strength of the magnetic field, when the current supply to the coil 122 is appropriately turned on/off through a controller (not shown in the drawing), the porous magnetorheological elastomer 130 . As the stiffness and volume of the body are repeatedly changed, the user can feel various tactile and kinesthetic sensations.

The porous magnetorheological elastomer (MRE) 130 is a polymer elastomer such as natural rubber and silicone rubber containing magnetic particles and forming a number of pores. It has the characteristic of changing elasticity and stiffness.

In addition, the porous magnetorheological elastomer 130 has much softer properties than a normal magnetorheological elastomer without pores due to a large number of pores formed therein, and due to these characteristics, it can provide a much softer touch and kinesthetic sensation to the user. there is an advantage

5, if a displacement of d1 occurs when the user applies pressure to the cover 140 in a state where no magnetic field is applied as shown in (a), in the state where a magnetic field is applied as shown in (b), the cover ( 140), displacement by d2 smaller than d1 occurs even when the same pressure is applied.

This is because, when a magnetic field is applied, even if pressure is applied from the outside, the magnetic particles receiving the force in the direction of the magnetic force line exert resistance to deformation. In addition, since the magnitude of the resistance is proportional to the strength of the magnetic field, the elasticity and strength of the porous magnetorheological elastomer 130 can be controlled by adjusting the strength of the magnetic field.

Therefore, by using these characteristics, it is possible to variously adjust the resistance felt when the user presses the cover 140 , and through this, various kinesthetic sensations can be provided to the user.

On the other hand, the porous magnetorheological elastomer 130 has a characteristic that the volume is slightly reduced when a magnetic field is applied. This is because, when a magnetic field is applied, the magnetic particles inside are oriented along the direction of the magnetic force and an attractive force is generated between them.

Using these characteristics, as shown in FIG. 6 , the porous magnetorheological elastomer 130 can be vibrated by periodically turning on/off the magnetic field. In this case, the user may feel the vibrating touch directly through the cover 140 or indirectly through the housing of the electronic device.

Hereinafter, a method of manufacturing the porous magnetorheological elastomer 130 will be described with reference to the flowchart of FIG. 7 .

First, a silicone rubber material, silicone oil and carbonyl iron (Carbonyl) powder are mixed. At this time, the weight ratio of the silicone rubber material, silicone oil, and carbonyl iron is preferably 1: (0.6 to 0.8): (6 to 8). (ST11)

Then, after adding ethanol to the above mixture, stirring is performed using a stirrer. At this time, the weight ratio of the silicone rubber material to the ethanol is preferably 1: (0.5 to 3.0). (ST12)

After performing the stirring operation, dispersion and homogenization using an ultrasonic homogenizer are performed for about 1 hour. (ST13)

After homogenization, the mixture is poured into a mold and cured. At this time, it is preferable to perform the curing operation while heating to a temperature of about 70 to 90 ° C. In this way, as the ethanol evaporates during the curing process, a number of pores are formed therein, thereby making the porous magnetorheological elastomer 130 .

On the other hand, if necessary, a magnetic field can be applied to the mixture during the curing operation. In this way, since the magnetic particles (carbonyl iron) are hardened in a state oriented along the direction of the magnetic field, the resistance to the external magnetic field will be different when compared to the magnetorheological elastomer in which the magnetic particles are uniformly dispersed.

Therefore, if the direction or strength of the magnetic field applied during curing is appropriately adjusted, the properties of the porous magnetorheological elastomer can be variously selected. (ST14, ST15)

8 is a scanning electron microscope (FESEM) photograph of the magnetorheological elastomer, (a) is a general magnetorheological elastomer, (b) to (d) is a porous magnetorheological elastomer 130 in which different amounts of ethanol are used. ) is shown.

Through this, it can be seen that there are few pores in the interior of the general magnetorheological elastomer, and in the case of the porous magnetorheological elastomer 130, as the amount of added ethanol increases, the amount of pores increases.

In addition, FIG. 9 is a graph showing the compression test results of the general magnetorheological elastomer and the porous magnetorheological elastomer 130. Through this, the general magnetorheological elastomer has a greater resistance than the porous magnetorheological elastomer 130, and the porous magnetorheological elastomer ( 130), it can be seen that as the amount of pores increases, the resistance decreases.

<Second embodiment>

10 is a cross-sectional view of an actuator 100a according to a second embodiment of the present invention, in which a porous magnetorheological elastomer 150 is additionally installed between the cover 140 and the porous magnetorheological elastomer 130. There is a difference from the first embodiment.

When the porous magnetorheological elastomer 130 and the general magnetorheological elastomer 150 are stacked up and down in this way, when no magnetic field is applied, the initial rigidity can be lowered compared to the case of using only the general magnetorheological elastomer 150, and the magnetic field is When applied, the rigidity can be increased compared to the case of using only the porous magnetorheological elastomer 130 .

Therefore, according to the second embodiment of the present invention, there is an advantage that the range of stiffness change can be further expanded compared to the first embodiment.

In addition, the magnetorheological elastomer 150 positioned on the upper portion may serve to reduce magnetic leakage occurring in the porous magneto-rheoelastic material 130 . To this end, it is preferable that the magneto-rheoelastic material 150 positioned at the upper portion contains more magnetic particles than the porous magneto-rheoelastic material 130 at the lower portion.

Meanwhile, as in the actuator 100b shown in FIG. 11 , a low-density porous magnetorheological elastomer 160 may be stacked on top of the porous magnetorheological elastomer 130 instead of the general magnetorheological elastomer 150 . Although the low-density porous magnetorheological elastomer 160 contains pores, the low-density porous magnetorheological elastomer 160 includes pores having a much smaller density than that of the porous magnetorheological elastomer 130 .

More precisely, the low-density porous magnetorheological elastomer 160 has a much smaller total volume of pores contained therein than that of the porous magnetorheological elastomer 130, and thus has a higher rigidity than that of the porous magnetorheological elastomer 130. have Therefore, from the user's point of view, it is possible to obtain a firm feeling compared to the case where only the porous magnetorheological elastic body 130 is installed.

Meanwhile, the laminated magnetorheological elastomers 130 , 150 , 160 may be adhered to each other with an adhesive or the like, but is not limited thereto.

In addition, the magnetorheological elastomers 150 and 160 positioned above may be adhered to the bottom surface of the cover 140 , but is not limited thereto.

<Third embodiment>

12 is a cross-sectional view of the actuator 100c according to the third embodiment of the present invention, wherein the concave-convex magnetorheological elastic body 170 is installed between the cover 140 and the porous magnetorheological elastic body 130. The second embodiment There is a difference with the example.

The concave-convex magnetorheological elastomer 170 has a wavy concavo-convex structure formed on the bottom and upper surfaces, and may be a porous magnetorheological elastomer without pores as shown in the drawing or a low-density porous magnetorheological elastomer as described above.

When the concave-convex magnetorheological elastomer 170 is used, a predetermined space is formed between the cover 140 and the concave-convex magnetorheological elastomer 170, and the concave-convex magnetorheological elastomer 170 and the porous magnetorheological elastomer 130 are formed. Since a predetermined space is also formed between the two, the deformation width is increased when contracted or restored by a magnetic field, and the strength of vibration is increased when contracting and restoring at high speed.

On the other hand, although it is shown in the drawings that the concave-convex structure is formed on both surfaces of the concave-convex magnetorheological elastic body 170, the concave-convex structure may be formed only on one surface.

Also, in the drawings, the concave-convex structure of the concave-convex magnetorheological elastic body 170 is shown to have a wavy shape based on a cross section, but is not limited thereto. Therefore, it may have various types of concavo-convex structures such as a pyramid shape, an arch shape, etc. based on a cross-section.

In addition, although it is shown in the drawings that the porous magnetorheological elastomer 130 positioned at the bottom does not have a concave-convex structure, it is not limited thereto. Therefore, the concave-convex structure described above may also be formed on the upper surface or the lower surface of the porous magnetorheological elastomer 130 .

In addition, as shown in FIG. 3 , even when only the porous magnetorheological elastomer 130 is installed between the cover 140 and the magnetic field generating unit 120 , the concave-convex structure described above on the upper surface or the lower surface of the porous magnetorheological elastomer 130 can be formed. may be

<Fourth embodiment>

13 is a cross-sectional view of an actuator 100d according to a fourth embodiment of the present invention, and is different from other embodiments in that the pressure sensor 180 is installed under the cover 140 .

Since the pressure sensor 180 is to detect a user's pressing force, it is preferable to be installed under the cover 140, but the installation location is not limited thereto.

In this way, when the pressure sensor 180 is installed to detect the user's pressing force, there is an advantage in that the operation of the actuator 100d can be controlled according to the degree of the user's pressing force.

As an example, when the actuator 100d is in the standby mode, current is not supplied to the magnetic field generator 120 , and it is confirmed that the measured value of the pressure sensor 180 falls within the first setting range due to the user's manipulation. The controller of the actuator 100d or the CPU of the electronic device controls the first current to be supplied to the magnetic field generator 120, and the measured value of the pressure sensor 180 is greater than the first set range. If it is confirmed that it belongs to the magnetic field generator 120, it is possible to control the supply of a second current greater than the first current.

In this way, as the user's pressing force increases, the rigidity of the magnetorheological elastomers 130 and 150 increases and the effect of exhibiting greater resistance can be obtained.

As another example, when the actuator 100d is in standby mode or pressure is not detected by the pressure sensor 180, a strong first current is applied to the magnetic field generator 120 to provide a hard feeling to the user, and the pressure sensor When it is confirmed that the measured value of 180 is within the first setting range, control is performed so that a second current smaller than the first current is supplied to the magnetic field generator 120 , and the measured value of the pressure sensor 180 is set to the first setting If it is confirmed that the range is within the second set range larger than the range, the magnetic field generator 120 may be controlled to supply a third current smaller than the second current.

In this way, the user initially feels hard, and as the pressing force increases, the rigidity of the magnetorheological elastomers 130 and 150 is gradually reduced, thereby providing an effect of providing a more flexible feeling.

As another example, when it is confirmed that the measured value of the pressure sensor 180 falls within the first setting range, the current supply to the magnetic field generator 120 is turned on/off at the first frequency, and the pressure sensor 180 is turned on/off. When it is confirmed that the measured value of is within the second set range larger than the first set range, the current supply to the magnetic field generator 120 may be controlled to turn on/off at a second frequency different from the first frequency.

In this way, when the user presses strongly, a high frequency vibration feedback is provided, and when the user presses lightly, a low frequency vibration feedback is provided, thereby providing feedback of a frequency differentiated according to the degree of the user's pressing force. However, since the feedback method is not necessarily limited thereto, it is also possible to provide low-frequency vibration feedback when the user presses strongly, and provides high-frequency vibration feedback when the user presses lightly.

That is, when the pressure sensor 180 is installed in this way, it is possible to provide various tactile and kinesthetic sensations in response to the user's intention or motion.

In the above, preferred embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and may be modified or modified in various forms during a specific application process and implemented.

As an example, like the actuator 100e shown in the cross-sectional view of FIG. 14 , the porous magnetorheological elastomer 130 and the general magnetorheological elastomer 150 are not continuously stacked up and down, but in the upper and lower portions of the magnetic field generator 120 . Each may be placed separately.

Even in this case, the pressure sensor 180 may be additionally installed on the bottom surface of the cover 140, and at least one of the porous magnetorheological elastomer 130 and the porous magnetorheological elastomer 150 has a concave-convex structure on the surface. You may. In addition, a low-density porous magnetorheological elastomer 160 may be used in place of the porous magnetorheological elastomer 150 without pores.

As another example, as shown in FIGS. 15 and 16 , the cover 140a may not be coupled to the upper end of the side wall of the housing 110 , but may be directly coupled only to the upper portion of the magnetorheological elastomers 130 and 150 with an adhesive or the like.

As such, the present invention is not limited to the above-described embodiments, and may be modified or modified in various forms and implemented, and the modified or modified embodiments are also entitled to the right of the present invention if they include the technical spirit of the present invention disclosed in the claims to be described later. It would be natural to fall within the scope.

100: actuator 110: housing 112: locking projection
120: magnetic field generator 122: coil 124: magnetic core
130: porous magnetorheological elastomer 132: elastic substrate 134: pores
140: cover 142: guide groove 144: jamming jaw
150: magnetorheological elastomer 160: low-density porous magnetorheological elastomer
170: concave-convex magnetorheological elastomer 180: pressure sensor

Claims (9)

a magnetic field generator installed inside the housing;
A porous magnetorheological elastomer installed on the upper portion of the magnetic field generator;
Cover disposed on top of porous magnetorheological elastomer
Skin sensory and kinesthetic stimulation actuator comprising According to claim 1,
The porous magnetorheological elastomer includes a silicone rubber material, silicone oil, and carbonyl iron in a weight ratio of 1: (0.6 to 0.8): (6 to 8), respectively. Skin sensory and kinesthetic stimulation actuator According to claim 1,
Skin sensory and kinesthetic stimulation actuator, characterized in that a magnetorheological elastic body without pores is installed between the cover and the porous magnetorheological elastic body According to claim 1,
At least one of the porous magnetorheological elastomer and the porous magnetorheological elastomer has a skin sensory and kinesthetic stimulation actuator, characterized in that an uneven portion is formed on the surface. According to claim 1,
Skin sensory and kinesthetic stimulation actuator, characterized in that a low-density porous magnetorheological elastomer having a smaller pore content than that of the porous magnetorheological elastomer is installed between the cover and the porous magnetorheological elastomer. According to claim 1,
It includes a pressure sensor that detects the user's pressing force,
When the measured value of the pressure sensor falls within a first set range, a first current is supplied to the magnetic field generator, and when the measured value of the pressure sensor falls within a second set range that is larger than the first set range, the Skin sensory and kinesthetic stimulation actuator, characterized in that a second current greater than the first current is supplied to the magnetic field generator According to claim 1,
It includes a pressure sensor that detects the user's pressing force,
When the measured value of the pressure sensor falls within a first set range, the first current is supplied to the magnetic field generator, and the measured value of the pressure sensor falls within a second set range that is larger than the first set range Skin sensory and kinesthetic stimulation actuator, characterized in that a second current smaller than the first current is supplied to the magnetic field generator According to claim 1,
It includes a pressure sensor that detects the user's pressing force,
When the measured value of the pressure sensor falls within a first set range, the magnetic field generator is turned on/off at a first frequency, and the measured value of the pressure sensor falls within a second set range that is larger than the first set range Skin sensory and kinesthetic stimulation actuator, characterized in that the magnetic field generator turns on/off at a second frequency different from the first frequency According to claim 1,
A guide groove into which the upper end of the side wall of the housing is inserted is formed on the edge of the bottom surface of the cover, and a blocking protrusion having a width greater than the entrance of the guide groove is formed on the side wall of the housing.

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