Lower limb force sensation presentation device and lower limb force sensation presentation method using the device.

Abstract

To provide a lower limb force sense presentation device capable of presenting a user with a force sense applied to each lower limb when the lower limb falls while enabling the user to move over a wide area by walking, and to provide a lower limb force sense presentation method using this device.SOLUTION: A lower limb force sense presentation device 10 that is used together with a video display device 11 that provides visual information and presents a force sense to each lower limb of a user 90. The lower limb force sense presentation device 10 includes a pair of plantar force sense presentation units 12 configured to be attachable to left and right feet 92 of the user 90, and a control unit 18 configured to control operations of the plantar force sense presentation units 12. Each plantar force sense presentation unit 12 includes a bottom portion 20, a foot placement portion 22 to be attached to the foot 92 when the foot is placed thereon, and a lifting mechanism 30 for raising and lowering the foot placement portion 22 with respect to the bottom portion 20. The control unit 18 controls the lifting mechanism 30 so as to lower the foot placement portion 22 at a predetermined acceleration in synchronization with a timing when a falling video is provided by the video display device 11.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lower limb force sensation presentation device and a force sensation presentation method, and more particularly to a lower limb force sensation presentation device that presents lower limb force sensation together with visual information and a lower limb force sensation presentation method using the lower limb force sensation presentation device.

Background Art

[0002] Conventionally, in a game machine or the like, a virtual reality experience device has been developed in which a user wears a head-mounted display (HMD) on the head and views a stereoscopic image by computer graphics. In such a virtual reality experience device, in order to give the user a sense of reality, there is known one provided with a force sensation presentation device that imparts a force sensation to the lower limb portion of the user together with the video. Such a force sensation presentation device does not impart to the user a movement corresponding to the actual falling speed and falling distance, but can give a higher sense of presence in combination with visual recognition by imparting the necessary force sensation.

[0003] For example, Patent Document 1 discloses a device that presents a falling sensation to a user using an HMD and a force sensation presentation device having an elevating stage. In this device, with the HMD worn on the user's head, the user is placed on the stage of the force sensation presentation device where the stage is in the raised position. In this state, while the user is made to view a video of falling from a high place by the HMD, if the stage of the force sensation presentation device is instantaneously moved from the raised position to the lowered position at the time of falling, the user can obtain a feeling as if gravity acts on the body and falls from a high place together with the visual sensation of falling.

[0004] Also, Non-Patent Document 1 discloses a shoe-type force sensation presentation device worn on the left and right feet of a user. In this shoe-type force sensation presentation device, an MR fluid actuator and a spring that expand and contract in the vertical direction are mounted between the lower surface of the shoe-type mounting portion into which the user's foot is inserted and the outsole portion that contacts the ground.

[0005] In this shoe-shaped force feedback device, the MR fluid actuators are mounted at two locations, namely the front and rear of the lower surface of the mounting part, and the spring is mounted between the two MR fluid actuators so as to be vertically stretchable. When pressure is applied from above, this MR fluid actuator contracts, and when released from the pressure, it extends by the restoring force of the coil spring incorporated in the actuator. Further, the MR fluid actuator can change the viscosity of the internal MR fluid (Magneto-Rheological Fluid) by changing the magnetic field within the actuator, thereby changing the degree of contraction in response to the same pressure from above. The spring balances the forces from the two fluid actuators acting on the sole of the foot and assists the restoring force of the MR fluid actuator.

[0006] In this shoe-shaped force feedback device, when the user inserts their feet into the mounting part and wears the shoe-shaped force feedback device on both feet, they can perform a walking motion. At this time, by changing the viscosity of the MR fluid within the MR fluid actuator, the sense of force acting on the user's sole during walking can be changed, and a plurality of walking sensations with different road surface conditions can be presented. For example, by increasing the viscosity of the MR fluid, a sensation of walking on mud can be presented, or by decreasing the viscosity of the MR fluid, a sensation of walking on grass can be presented.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Non-Patent Documents

[0008]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the force sensation presentation device described in Patent Document 1, although it is possible to present the force sensation at the time of falling to the user, it can only present the force sensation on the stage, and the user cannot experience virtual reality while walking by himself / herself.

[0010] On the other hand, in the shoe-type force sensation presentation device described in Non-Patent Document 1, while the user is wearing the shoe-type force sensation presentation devices on both feet, it is possible to present various force sensations to the soles of the feet while the user is walking, but it is not possible to present the force sensation at the time of falling to the user.

[0011] The present invention has been made in view of the above problems, and is a lower limb force sensation presentation device that presents force sensation to the lower limbs of a user together with visual information, and enables a wide range of movement by the user's own walking, and aims to provide a lower limb force sensation presentation device capable of presenting the force sensation applied to the lower limbs at the time of falling to the user and a lower limb force sensation presentation method using the device.

Means for Solving the Problems

[0012] In order to achieve the above object, the invention according to claim 1 of the present invention is a lower limb force sensation presentation device that presents force sensation, comprising a pair of sole force sensation presentation parts configured to be attachable to the left and right feet of a user, and a control part that controls the operation of the sole force sensation presentation parts, and each sole force sensation presentation part includes a bottom part that forms a ground contact surface, a foot placement part provided above the bottom part and attached to the foot in a state where the user's foot is placed thereon, and a lifting mechanism disposed between the bottom part and the foot placement part and configured to raise and lower the foot placement part with respect to the bottom part. The elevating mechanism is composed of links formed in a rhombus shape, and includes a pantograph structure portion with a lower end fixed to the bottom and capable of expanding and contracting in the vertical direction, and an actuator connected to the pantograph structure portion for expanding and contracting the pantograph structure portion. The pantograph structure portion is provided in pairs on both the left and right sides of the bottom of each sole force sensation presenting portion. The actuator is an artificial muscle and is disposed between the paired pantograph structure portions. The control part is characterized in that it controls the lifting mechanism to lower the foot placement part at a predetermined acceleration in synchronization with the timing at which a falling image is provided by the video display device. In addition, in order to achieve the above object, the invention according to claim 2 of the present invention is used together with a video display device that provides visual information to a user, and in a lower limb force sensation presenting device that presents a force sensation to the lower limbs of the user, it includes a pair of sole force sensation presenting portions configured to be wearable on the left and right feet of the user, and a control unit that controls the operation of the sole force sensation presenting portions. Each sole force sensation presenting portion includes a bottom portion that forms a ground contact surface, a foot placement portion provided above the bottom portion and worn on the foot in a state where the user's foot is placed thereon, an elevating mechanism disposed between the bottom portion and the foot placement portion for raising and lowering the foot placement portion with respect to the bottom portion, and an inclination mechanism disposed between the bottom portion and the foot placement portion for inclining the foot placement portion in the front-rear direction with respect to the bottom portion. The elevating mechanism is composed of links formed in a rhombus shape, and includes a pantograph structure portion with a lower end fixed to the bottom and capable of expanding and contracting in the vertical direction, and an actuator connected to the pantograph structure portion for expanding and contracting the pantograph structure portion. The inclination mechanism is provided at the front portion and the rear portion of the bottom portion respectively, and is formed in a columnar shape capable of expanding and contracting in the vertical direction. The control unit is characterized by controlling the elevating mechanism so as to lower the foot placement portion at a predetermined acceleration in synchronization with the timing when a falling video is provided by the video display device. Also, in order to achieve the above object, the invention according to claim 3 of the present invention is used together with a video display device that provides visual information to a user, and in a lower limb force sensation presentation device that presents a sense of force to the lower limbs of the user, a pair of sole force sensation presentation parts configured to be attachable to the left and right feet of the user, a control part that controls the operation of the sole force sensation presentation part, a floor board that forms a floor surface on which the user can walk while wearing the sole force sensation presentation part, and a bottom fixing mechanism that can switch the bottom part that forms the ground contact surface in each sole force sensation presentation part between a fixed state and a released state with respect to the floor board. Each sole force sensation presentation part is provided above the bottom part, and includes a foot placement part that is attached to the foot in a state where the user's foot is placed, and a lifting mechanism that is disposed between the bottom part and the foot placement part and raises and lowers the foot placement part with respect to the bottom part. The lifting mechanism is composed of links formed in a rhombus shape, and includes a pantograph structure part whose lower end is fixed to the bottom part and is vertically expandable and contractible, and an actuator that is connected to the pantograph structure part and expands and contracts the pantograph structure part. The bottom fixing mechanism is built in the bottom part and / or the floor board of the sole force sensation presentation part, and the control part controls the lifting mechanism so as to lower the foot placement part at a predetermined acceleration in synchronization with the timing when a falling video is provided by the video display device.

[0013] According to this configuration, the user can walk with a pair of plantar force sensation presentation units attached to the left and right feet. Then, in synchronization with the provision of the falling video by the video display device, the foot placement part of the plantar force sensation presentation unit is given a movement of descending at a predetermined acceleration by the lifting mechanism. That is, while maintaining a walkable situation, a predetermined acceleration in the falling direction is applied to both feet of the user. Thus, although it is a relatively small movement within the lifting range by the lifting mechanism, while presenting an illusion (vection effect) of moving in the falling direction to the user by visual information, by presenting an acceleration in the falling direction, the sense of presence of the falling sensation is enhanced, and the user can experience a highly immersive virtual reality experience.

[0015] Also, in the invention according to claim 4 2, in the lower limb force sensation presentation device described in claim 2 Or 3 the actuator is an artificial muscle that expands and contracts in the axial direction by a change in the fluid pressure supplied inside a cylindrical elastic body, and the pantograph structure part expands and contracts in conjunction with the expansion and contraction operation of the artificial muscle.

[0016] According to this configuration, since an artificial muscle that expands and contracts by a fluid pressure such as air is used as a drive source for expanding and contracting the pantograph structure part in the vertical direction, the weight of the plantar force sensation presentation unit can be reduced. Also, since the artificial muscle can be instantaneously expanded and contracted by the supplied fluid pressure, when presenting the force sensation of falling, the lifting mechanism can be instantaneously lowered at the moment of falling, and a highly immersive falling sensation can be given to the user.

[0017] Also, The invention according to claim 5 is the lower limb force sensation presentation device according to claim 1 or 3, and includes an inclination mechanism that is disposed between the bottom part and the foot placement part and inclines the foot placement part in the front-rear direction with respect to the bottom part. characterized by this.

[0018] According to this configuration, when the user walks with the foot placement part of the sole force sensation presentation part inclined by the inclination mechanism, for example, a sense of force when walking on an inclined surface can be presented to the sole of the foot, and variations can be given to the sense of force during walking presented to the user's foot. That is, it is possible to give a sense of reality of actual inclined surface walking only by the movement of the sole force sensation presentation part in a state where walking is possible.

[0019] Further, the invention according to claim 6 is the lower limb force sensation presentation device according to claim 1 or 2, and includes a floor board that forms a floor surface on which the user can walk while wearing the sole force sensation presentation part, and a bottom fixing mechanism that is built in the bottom part and / or the floor board of the sole force sensation presentation part and can switch the bottom part between a fixed state and a released state with respect to the floor board.

[0020] According to this configuration, by means of the bottom fixing mechanism, the bottom of the plantar force sensation presenting part is fixed to the floor board, so that the both feet of the user wearing the plantar force sensation presenting part can be fixed on the floor board. Thereby, for example, when presenting a sense of falling, it is possible to prohibit the user from walking, or to present a sitting-on-a-chair feeling by bending the user's legs by the leg force sensation presenting part with the both feet of the user fixed. Also, by switching the bottom from the fixed state to the released state, the user can be made to be in a state where walking is possible.

[0021] Moreover, the invention according to claim 7 is the lower limb force sensation presenting device according to any one of claims 1 to 6, characterized in that the elevating mechanism includes a braking part that applies a braking force to the contraction operation in a situation where the pantograph structure part contracts due to the user's own weight.

[0022] Also, the invention according to claim 8 is, in the lower limb force sensation presentation device described in claim 7 characterized by The braking part is a functional fluid braking part capable of adjusting the braking force by a change in viscosity of the functional fluid filled therein due to an external stimulus. being as follows.

[0023] According to this configuration, When the user wears the plantar force sensation presenting part and walks, and the pantograph structure part of the elevating mechanism contracts due to the user's own weight, that is, in a situation where the foot placement part descends, the functional fluid braking part can apply braking forces of various magnitudes to the descending operation of the foot placement part. Thereby, it is possible to change the sense of force acting on the sole of the foot and present to the user a walking feeling on various road surface conditions (for example, on water or mud).

[0024] Also, the invention according to claim 9 is, in the lower limb force sensation presentation device described in any one of claims 1 to 8 characterized by It includes a pair of exoskeleton-type leg force sensation presenting parts worn on the user's thigh and lower leg. Each leg force sensation presenting part includes a first frame part worn on the thigh, a second frame part worn on the lower leg, and a joint driving part disposed between the lower end of the first frame part and the upper end of the second frame part, and configured to flex and extend the first frame part and the second frame part. The joint driving part bends or extends the first frame part and the second frame part in synchronization with the timing when visual information indicating that a force in the gravitational direction or the anti-gravitational direction acts on the user's leg is presented by the video display device. being as follows.

[0025] According to this configuration, In a situation where visual information in which a force in the direction of gravity or against gravity acts on the user's legs is presented, the joint drive unit of the leg force feedback unit bends or extends the first frame unit and the second frame unit, that is, intentionally bends or extends the user's thighs and lower legs, thereby enabling the presentation of the sense of force of gravity or against gravity acting on the legs. For example, in a situation where visual information is presented such that the user falls from a high place and lands on both feet, by intentionally bending the user's thighs and lower legs, the sense of gravity acting on the legs at the time of landing can be presented, or in a situation where visual information that the user jumps is presented, by intentionally extending the user's thighs and lower legs, a feeling of jumping to a high place against gravity can be presented.

[0026] Also, the invention according to claim 10 is a lower limb force sensation presentation method for presenting force sensation together with a falling image by the video display device using the lower limb force sensation presentation device described in any one of claims 1 to 9 and includes a step of lowering the foot placement portion of the plantar force sensation presentation portion at a first acceleration at the initial stage of the fall, a step of decelerating the foot placement portion from the first acceleration and stopping the fall during the fall, and a step of lowering the foot placement portion at a second acceleration and then stopping the fall at the end of the fall.

[0027] According to this configuration, at the initial stage of the fall of the falling image, a downward acceleration acts on the left and right soles of the user's feet, so that the user can be presented with the feeling that the fall has started. Also, during the fall, while maintaining the feeling of falling due to the vector effect of the falling image, the foot placement part is decelerated from the first acceleration and the descent is stopped, so that the descent distance of the foot placement part can be reduced. Further, at the end of the fall, by applying a downward acceleration to the left and right soles of the user's feet again to stop the descent, the user can be presented with the feeling of landing. As a result, while reducing the descent distance of the foot placement part, the sense of force during the fall can be presented, so that the foot sole force feedback part can be miniaturized.

Advantages of the Invention

[0028] According to the lower limb force feedback device of the present invention, while the user maintains a state where walking is possible, in a state where a falling image is provided by the video display device, the foot placement part of the foot sole force feedback part is lowered at a predetermined acceleration to present a sense of force to the user's foot sole, so that a highly immersive feeling of falling can be presented while making a small movement within the lifting range of the foot sole force feedback part. Further, according to the lower limb force feedback method of the present invention, in addition to the above effects, the foot sole force feedback part can be miniaturized.

Brief Description of the Drawings

[0029]

Figure 1

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Figure 13A

Figure 13B

Mode for Carrying Out the Invention

[0030] FIG. 1 is a schematic explanatory view of a lower limb force sensation presenting device 10 according to an embodiment of the present invention. The lower limb force sensation presenting device 10 is used together with a head-mounted display (hereinafter, also simply referred to as "HMD") 11 which is a video display device that provides visual information to a user 90, and is a device that presents a sense of force to the lower limbs of the user 90. The lower limb force sensation presenting device 10 of the present embodiment includes a pair of plantar force sensation presenting parts 12 attached to the left and right feet 92 of the user 90, a pair of exoskeleton-type leg force sensation presenting parts 14 attached to the left and right legs 94 of the user 90, a floor board 16 forming a floor surface, and a control device (control unit) 18. The control device 18 is electrically connected to the HMD 11, the plantar force sensation presenting part 12, and the leg force sensation presenting part 16 by wire and / or wirelessly. Hereinafter, each part of the lower limb force sensation presenting device 10 will be described in detail.

[0031] The HMD11 is a glasses-type display worn on the head 91 of the user 90, and displays a three-dimensional image on the display. Note that the image display device is not limited to the HMD11, and any device capable of displaying a two-dimensional or three-dimensional image to the user 90 may be used. For example, a display device that displays an image on a screen may be used.

[0032] The plantar force feedback unit 12 constitutes a device for providing force feedback to the soles of the feet of the user 90. FIG. 2 is a perspective view showing one of the pair of plantar force feedback units 12, and FIG. 3 is an exploded perspective view of the plantar force feedback unit 12. Since the other plantar force feedback unit 12 has the same configuration, the description thereof is omitted here. The plantar force feedback unit 12 includes a bottom 20 that forms a ground contact surface, a footrest 22 that is a footrest portion worn on the foot 92 in a state where the foot 92 of the user 90 is placed, a fixture 24 for fixing the foot 92 of the user 90 to the footrest 24, and a lifting mechanism 30 disposed between the bottom 20 and the footrest 22. In the following description, the front refers to the direction of the toe side in a state where the plantar force feedback unit 12 is worn on the foot 92, and the rear refers to the direction of the heel side.

[0033] The bottom 20 can be formed of, for example, a resin material or the like, and is formed in a substantially flat plate shape. In order to provide cushioning when in contact with the ground, the bottom 20 is preferably formed of an elastic material such as a rubber material.

[0034] As shown in FIG. 3, an electromagnet 26 is built into the bottom 20. The magnetic force of this electromagnet 26 is controlled by the control device 18. In the present embodiment, thin electromagnets 26 are built into the front part, the central part, and the rear part of the bottom 20, respectively, and each electromagnet 26 is controlled individually. In the present embodiment, the floor board 16 is formed of an iron plate, and the electromagnet 26 constitutes a bottom fixing mechanism capable of switching the bottom 20 between a fixed state and a released state with respect to the floor board 16. Specifically, by increasing the magnetic force of the electromagnet 26 by the control device 18, the bottom 20 is in a fixed state fixed to the floor surface, and by demagnetizing the electromagnet 80, the fixed state by the magnetic force is released and the released state is obtained.

[0035] The foot placement table 22 is a plate-shaped part provided above the bottom 20 via the lifting mechanism 30. The bottom 20 and the foot placement table 22 are formed in substantially the same shape in plan view, and are preferably set in the range of the width dimension in the left-right direction of about 70 mm to 12 mm.

[0036] The fixture 24 is attached to the foot placement table 22 and fixes the user's 90 foot 92 on the foot placement table 22. In the present embodiment, as an example of the fixture 24, a pair of belt-shaped hook-and-loop fasteners with one end fixed to both side portions of the foot placement table 22 is used. One of the hook-and-loop fasteners is composed of a male-type hook-and-loop fastener, and the other is composed of a female-type hook-and-loop fastener. Note that the fixture 24 is not limited to the hook-and-loop fastener, and for example, it may be a hook-and-loop fastener, or may have a structure in which buckles are provided at the ends of a pair of belt-shaped members with one end fixed to the foot placement table 22. Note that the foot placement part of the present embodiment is configured to attach the foot placement table 22 to the user's 90 foot 92 using the fixture 24, but the foot placement part itself may have a shoe shape and may be configured such that the foot 92 can be inserted and worn. Further, such a shoe shape, the foot placement part, and the fixture 24 such as a hook-and-loop fastener may be used in combination. When the hook-and-loop fastener is used as the fixture 24 as in the present embodiment, as shown in FIG. 6A, the user 90 can fix the foot 92 to the foot placement table 22 in a state of wearing the sandals 98 or shoes.

[0037] The lifting mechanism 30 moves the foot placement table 22 so that the foot placement table 22 approaches and separates from the bottom 20, that is, it is a mechanism that raises and lowers the foot placement table 22 with respect to the grounded bottom 20, and has a drive unit that raises and lowers the foot placement table 22 at a predetermined acceleration. As shown in FIG. 3, the lifting mechanism 30 of the present embodiment includes a flat base 31, a pantograph structure portion 32 installed on the base 31, a McKibben type artificial muscle (actuator) 40 that is a drive unit, an MR fluid braking portion (braking portion) 50, and a biasing member 59.

[0038] The base 31 is a plate material laminated and fixed on the upper surface of the bottom portion 20. In the present embodiment, the base 31 is formed in substantially the same shape as the bottom portion 20 in plan view.

[0039] The pantograph structure portion 32 is a parallel link composed of four links formed in a rhombus shape, and is installed in pairs on both the left and right sides of the base 31. The lower end portion of the pantograph structure portion 32 is fixed to the base 31 via the lower mounting plate 34, and the foot placement table 22 is attached to the upper end portion via the upper mounting plate 36. As shown in FIG. 2, in this pantograph structure portion 32, pins 33a and 33b attached to the lower end portion and the upper end portion respectively move within guide holes 34a and 36a extending in the front-rear direction formed in the lower mounting plate 34 and the upper mounting plate 36, thereby being formed to be telescopically extendable in the vertical direction. The foot placement table 22 moves in the vertical direction along with the telescopic movement of the pantograph structure portion. In the present embodiment, the foot placement table 22 is configured to move up and down along the inner surface of a guide plate 38 having an arcuate cross-section erected at the rear end portion of the base 31.

[0040] The artificial muscle 40 applies a driving force for expanding and contracting the pantograph structure portion 32, and includes a hollow cylindrical elastic body 42 and a fluid supply means (not shown) for supplying fluid inside the elastic body 42. One end of the elastic body 42 is closed, and the other end has an opening, and this opening is connected to the fluid supply means via an on-off valve. The artificial muscle 40 expands and contracts in the axial direction due to a change in the fluid pressure supplied inside the elastic body 42. In the present embodiment, it contracts by supplying air, and expands when the supplied air is discharged from inside the elastic body 42. The amount of air supplied and discharged can be controlled by the control device 18. The artificial muscle 40 is disposed between the left and right pantograph structure portions 32 such that the axial direction thereof coincides with the front-rear direction of the plantar force sensation presenting portion 12, and both axial ends of the artificial muscle 40 are connected to two opposing joint portions of the rhombic pantograph structure portion 32 via connectors 44. When the artificial muscle 40 contracts, the pantograph structure portion 32 extends to raise the foot placement table 22, and when the artificial muscle 40 extends, the pantograph structure portion 32 contracts to lower the foot placement table 22.

[0041] The artificial muscle 40 can be in a state where the opening of the elastic body 42 is opened and the driving force applied to the pantograph structure portion 32 is stopped. In this state, when the user 90 gets on the footrest 22 in the raised position, the pantograph structure portion 32 contracts to the lowered position by the weight of the user 90.

[0042] Next, with reference to FIG. 4, the MR fluid braking portion 50 that applies a braking force to the pantograph structure portion 32 will be described. The MR fluid braking portion 50 is an MR fluid braking device having a braking function using a magneto-rheological fluid (hereinafter referred to as "MR fluid") 51. This MR fluid braking portion 50 applies a braking force to the contraction operation of the pantograph structure portion 32, that is, the downward movement of the footrest 22, in a situation where the pantograph structure portion 32 contracts due to the weight of the user. The MR fluid is composed of a mixed fluid of oil and ferromagnetic particles, and its viscosity changes when a magnetic field is applied. The MR fluid braking portion 50 has a cylindrical case 52, a core 54 disposed at the central portion of the case 52, a coil 55 wound around the core 54, a plurality of disks 56, 57 disposed around the coil 55, and the MR fluid 51 filled in the accommodation space of the disks 56, 57. The disks 56, 57 include a fixed disk 56 fixed to the case 52 and a movable disk 57 rotatable together with the core 54, and each disk 56, 57 is arranged in multiple layers in the axial direction of the coil 54. By applying an electric current to the coil, the viscosity of the MR fluid filled inside the case 52 changes in this MR fluid braking portion 50, and thereby the magnitude of the braking force can be adjusted. The magnitude of the braking force can be controlled by the control device 18.

[0043] The biasing member 59 is composed of a coil spring having one end connected to the footrest 22 and the other end connected to the upper end portion of the guide plate 38. The biasing member 59 is attached to the left and right side portions of the footrest 22, and applies an upward biasing force to the footrest 22 so as to assist the braking force by the MR fluid braking portion 50.

[0044] FIG. 5 is a side view of the plantar force sensation presenting unit 12 described above. When the user 90 is not placing the foot 92 thereon, the foot placement portion 22 is in the initial position where it is raised the most. FIGS. 6A and 6B show a state in which the foot 92 is placed on the foot placement portion 22 and the foot placement portion 22 is in the lowered position where it is lowered the most due to the own weight of the user 90. When the user 90 walks, the foot placement portion 22 can be maintained in the lowered position shown in FIGS. 6A and 6B.

[0045] FIGS. 7A and 7B show a state in which the foot 92 is placed on the foot placement portion 22 and the foot placement portion 22 is raised to the raised position by the driving force of the artificial muscle 40. When the foot placement portion 22 is lowered together with the falling image by the HMD 11, the foot placement table 22 is moved from the raised position shown in FIGS. 7A and 7B to the lowered position shown in FIGS. 6A and 6B. The distance from the raised position to the lowered position is preferably set in the range of about 200 mm to about 50 mm, and more preferably in the range of about 100 mm to about 60 mm. In the present embodiment, it is set to about 75 mm.

[0046] Next, with reference to FIG. 8, the leg force sensation presenting unit 14 attached to the thigh portion 94a and the lower leg portion 94b of the user 90 will be described. The leg force sensation presenting unit 14 constitutes an exoskeleton type force sensation presenting device. The leg force sensation presenting unit 14 of the present embodiment includes a first frame portion 71 attached to the thigh portion 94a, a second frame portion 72 attached to the lower leg portion 94b, a joint driving portion 74 that bends and extends the first frame portion 71 and the second frame portion 72, an upper mounting tool 76, and a lower mounting tool 77.

[0047] The first frame portion 71 and the second frame portion 72 respectively form an exoskeleton of the thigh portion 94a and the lower leg portion 94, and are formed of long plate-like members. The first frame portion 71 is attached to the thigh portion 94a by the upper mounting tool 76 attached thereto, and the second frame portion 72 is attached to the lower leg portion 94b by the lower mounting tool 77 attached thereto. The upper mounting tool 76 and the lower mounting tool 77 can be formed by, for example, a hook-and-loop fastener or the like.

[0048] The joint drive unit 74 is disposed between the lower end of the first frame unit 71 and the upper end of the second frame unit 72. The joint drive unit 74 includes, inside a housing formed in a substantially cylindrical shape by a resin material or the like, a connecting mechanism that connects the first frame unit 71 and the second frame unit 72, and an actuator 75 that drives each frame unit 71, 72 via this connecting mechanism. The actuator 75 is driven under the control of the control device 18. The joint drive unit 74 relatively displaces the first frame unit 71 and the second frame unit 72 by the driving force of the actuator 75 to present a force sensation to the leg 94 of the user 90, thereby assisting the bending and stretching movement of the knee of the user 90's leg or applying a mechanical load to the leg 94. In the present embodiment, in synchronization with the timing at which visual information in which a force in the gravitational direction or the anti-gravitational direction acts on the leg 94 of the user 90 is presented by the HMD 11 based on a control signal from the control device 18, the joint drive unit 74 bends or extends the first frame unit 71 and the second frame unit 72.

[0049] In the present embodiment, a pair of leg force sensation presentation units 14 are connected via a connector 79. The connector 79 connects the pair of left and right leg force sensation presentation units 14 via a joint portion 78 connected to the upper end of the first frame unit 71, and the first frame unit 71 is formed to be rotatable about the joint portion 78 such that the lower end draws an arc.

[0050] The control device 18 is configured to include information processing means such as a central processing unit (CPU) and an application specific integrated circuit (ASIC), storage means such as a RAM and a ROM, an input / output interface, and the like. The control device 18 may be configured to be incorporated inside each of the HMD 11, the sole force sensation presentation unit 12, and the leg force sensation presentation unit 14, or may be configured to provide a separate control device 18 outside these devices, separate from the HMD 11, the sole force sensation presentation unit 12, and the leg force sensation presentation unit 14.

[0051] The control device 18 controls the operations of the sole force sensation presentation unit 12 and the leg force sensation presentation unit 14 according to a preset operation program so as to be synchronized with the timing of the video provided by the HMD 11. In the present embodiment, the control device 18 controls the elevating mechanism 30 so that the foot mounting table 22 of the sole force sensation presentation unit 12 descends at a predetermined acceleration in synchronization with the timing at which the HMD 11 provides a falling video. Further, the control device 18 controls the joint drive unit 74 so that the first frame portion 71 and the second frame portion 72 of the leg force sensation presentation unit 14 are bent in synchronization with the timing at which the HMD 11 provides a video from falling to landing.

[0052] In the above-described lower limb force sensation presentation device 10, a pair of sole force sensation presentation units 12 are attached to the left and right feet 92 of the user 90 by the attachment tool 24, and a pair of leg force sensation presentation units 14 are attached to the left and right legs 94 of the user 90 by the upper attachment tool 76 and the lower attachment tool 77. The user 90 can walk while wearing the sole force sensation presentation unit 12 and the leg force sensation presentation unit 14, and by this walking motion, a sense of force during walking is imparted to the lower limbs of the user 90. Further, while maintaining a walkable state, the lower limb force sensation presentation device 10 synchronizes with the falling video provided by the HMD 11, and the foot mounting table 22 of the sole force sensation presentation unit 12 is lowered at a predetermined acceleration by the elevating mechanism 30, so that a virtual reality experience with a highly immersive falling sensation can be achieved.

[0053] Next, a method of presenting a sense of force together with a falling video by the HMD 11 using the lower limb force sensation presentation device 10 will be described. FIG. 9 is a graph for explaining the time change of the descending speed presented by the sole force sensation presentation unit 12 together with the falling video. In FIG. 9, the vertical axis represents the speed of the foot mounting table 22 (i.e., the falling speed), the horizontal axis represents time, and the pictures shown on the time axis represent the falling video by the HMD 11. In FIG. 9, the falling speed of the foot mounting table 22 is shown by a solid line, and the falling speed when the user 90 actually experiences the situation shown by the HMD 11 (i.e., the falling speed when the user 90 freely falls from a high place) is shown by a broken line.

[0054] The lower limb force sensation presentation device 10 causes the foot placement table 22 of the sole force sensation presentation unit 12 to descend at a preset first acceleration a1 in synchronization with the timing at which the HMD 11 presents an image of the moment when the user 90 falls (i.e., the timing at the initial stage of the fall) (first acceleration step). Thereafter, in a situation where the HMD 11 presents an image during the fall, the foot placement table 22 is decelerated from the first acceleration at a predetermined acceleration a2 to zero speed, i.e., the descent of the foot placement table 22 is stopped (deceleration step). Then, in synchronization with the timing at which the HMD 11 presents an image transitioning from the fall to landing (i.e., the timing at the end of the fall), the stationary foot placement table 22 is descended at a second acceleration a4, and the foot placement table 22 is stopped from descending from the second acceleration at the timing of the landing image. Also, at the timing of landing by the HMD 11, the first frame portion 71 and the second frame portion 72 of the leg force sensation presentation unit 14 are bent to apply a load in the direction of gravity to the legs 94 of the user 90.

[0055] In this way, at the initial stage of the fall of the falling image by the HMD 11, by applying a downward acceleration to the left and right soles of the user 90, a feeling that the fall has started can be presented to the user 90. Also, during the fall, while maintaining the feeling of the fall by the vection effect of the falling image, by decelerating the foot placement table 22 from the first acceleration a1 and stopping the descent, the descent distance of the foot placement table 22 can be reduced. Further, at the end of the fall, by applying a downward acceleration to the left and right soles of the user 90 again and then stopping the descent, a feeling of landing can be presented to the user 90. Furthermore, since a load in the direction of gravity is applied to the thigh 94a and the lower leg 94b of the user 90 in synchronization with the timing of landing, a more immersive falling experience can be obtained. In this way, in the sole force sensation presenting unit 12 of the present embodiment, when presenting the falling sensation, an acceleration in the falling direction is given to present the force sensation at the initial stage and the end of the fall when the force sensation applied to the lower limbs changes rapidly, and during the fall when the force sensation applied to the lower limbs is small, by decelerating and stopping the foot placement table 22, the movement amount of the foot placement table 22 can be reduced, and the sole force sensation presenting unit 12 can be miniaturized. Also, by using the vection effect of the falling image, an immersive falling sensation can be obtained while making the descent speed of the foot placement table 22 smaller than the falling speed in the real world shown by the broken line in the graph of FIG. 9. The first acceleration a1 and the second acceleration a4 when lowering the foot placement table 22 may be the same value or different values, and for example, they can be set to be 1 / 3 or less, preferably 1 / 5 or less of the gravitational acceleration in the real world. In the present embodiment, the acceleration is set to about 1 / 10.

[0056] As described above, while maintaining a situation where walking is possible, the lower limb force sensation presenting device 10 can apply a predetermined acceleration in the falling direction to both feet of the user 90 while being worn on the user 90. Although the movement of the sole force sensation presenting unit 12 is relatively small within the lifting range by the lifting mechanism 30, by presenting an acceleration in the falling direction while presenting an illusion (vection effect) of moving in the falling direction to the user 90 by visual information, the immersion of the falling sensation is improved, and the user 90 can have a highly immersive virtual reality experience.

[0057] Furthermore, since the sole force sensation presenting unit 12 uses the artificial muscle 40 that expands and contracts the elastic body 42 with pneumatic pressure as the drive source of the elevating mechanism 30, the weight of the sole force sensation presenting unit 12 can be reduced. In addition, since the artificial muscle 40 is excellent in the responsiveness of the expansion and contraction operation, the elevating mechanism 30 can be instantaneously lowered at the moment of dropping in the dropping video by the HMD 11, and a highly realistic dropping sensation can be given to the user 90.

[0058] Also, in the situation where the user 90 performs a walking motion, by changing the braking force of the MR fluid braking unit 50 according to the road surface situation displayed on the HMD 11, various force sensations can be presented to the foot of the user 90. For example, in the walking motion, when the user 90 raises the foot 92, the sole force sensation presenting unit 12 can set the foot mounting table 22 to a position raised by a predetermined distance from the lowered position by the artificial muscle 40. Then, when the weight of the user 90 is applied to the foot mounting table 22, the foot mounting table 22 can be configured to descend by the weight of the user 90. When the foot mounting table 22 descends, by applying braking forces of various magnitudes by the MR fluid braking unit 50, the force sensation acting on the sole can be changed, and thereby, for example, a feeling of walking in water or a feeling of walking on mud or sand can be presented.

[0059] In addition, in a situation where the visual information indicating that a force in the gravitational direction or the anti-gravitational direction acts on the leg 94 of the user 90 is presented by the HMD 11, the joint drive unit 74 of the leg force feedback unit 14 bends or extends the first frame unit 71 and the second frame unit 72, and intentionally bends or extends the thigh 94a and the lower leg 94b of the user 90, thereby being able to present the sense of force of gravity or anti-gravity acting on the leg 94. For example, as described above, in a situation where an image of the user 90 falling from a high place and landing on both feet is presented, by intentionally bending the leg 94, the sense of gravity acting on the leg 94 at the time of landing can be presented. Also, for example, in a situation where visual information indicating that the user 90 jumps to a higher place than the real world is presented, by intentionally extending the leg 94 of the user 90, it is possible to present a feeling of jumping to a higher place against gravity. Further, together with the image of jumping, the sole force feedback device 12 is moved from the lowered position to the raised position, and the sense of force of moving upward can be presented. Also, in synchronization with the timing of the video of ascending and descending stairs, by bending or extending the first frame unit 71 and the second frame unit 72, the load applied to the leg 94 during the ascending and descending operations of the stairs can be made lighter or heavier. At this time, by changing the height position of the foot placement table 22 of the sole force feedback unit 12 left and right, the step difference of the stairs can be reproduced, and the sense of force during ascending and descending stairs can be presented on the sole of the foot.

[0060] Also, in the lower limb planning presentation device 10 of the present embodiment, the foot 92 of the user 90 can be fixed to the floor board 16 by the magnetic force of the electromagnet 26 which is the bottom fixing mechanism provided at the bottom 12 of the sole force feedback unit 12. Thereby, when presenting the sense of falling, it is possible to prohibit the user 90 from walking. Also, since the leg force feedback unit 14 has the effect of changing the center of gravity position of the user 90, in a state where both feet of the user 90 are fixed by the bottom fixing mechanism, by bending the leg of the user 90 by the leg force feedback unit 14, it is possible to present a feeling of sitting on a chair. Also, by controlling the adhesive force between the bottom 20 and the floor surface 16, such as weakening the magnetic force of the electromagnet 26, it is also possible to present a feeling to the user 90 as if walking on mud.

[0061] Next, another embodiment of the plantar force sensation presenting unit 12 will be described with reference to FIGS. 10 to 13. In FIGS. 10 to 13, the parts corresponding to those in the above-described embodiment are denoted by the same reference numerals. In the other embodiments described below, detailed descriptions of the same configurations as those in the above-described embodiment will be omitted.

[0062] FIG. 10 is a side view showing another embodiment of the plantar force sensation presenting unit 12, and FIG. 11 is an exploded perspective view of the plantar force sensation presenting unit 12 shown in FIG. 10. The plantar force sensation presenting unit 12 of this embodiment includes an inclination mechanism 60 that inclines the foot placement table 22 with respect to the bottom portion 20. In the plantar force sensation presenting unit 12, since the configurations other than the inclination mechanism 60 are the same as those in the previous embodiment, the details thereof are omitted here.

[0063] The inclination mechanism 60 is disposed between the bottom portion 20 and the foot placement table 22 of the plantar force sensation presenting unit 12, and includes a first cylinder 62 disposed at the front portion of the bottom portion 20 and a second cylinder 64 disposed at the rear portion of the bottom portion 20. In this embodiment, each of the cylinders 62 and 64 is disposed at the central portion in the left-right direction of the bottom portion 20, and is disposed on the front side and the rear side of the bottom portion 20 with the artificial muscle 40 interposed therebetween.

[0064] The first cylinder 62 and the second cylinder 64 are formed in a columnar shape, and are telescopic cylinders that can be expanded and contracted in the axial direction by a fluid pressure such as air pressure or hydraulic pressure. Each of the cylinders 62 and 64 has a lower end portion fixed to the upper surface of the base 31 and a contact portion 66 that can come into contact with the foot placement table 22 at the upper end portion. The contact portion 66 is formed in a non-fixed state with respect to the foot placement table 22 so as to be able to contact and separate from the lower surface of the foot placement table 22. This contact portion 66 is preferably formed of a flexible material such as a rubber material or a foaming material.

[0065] As shown in FIG. 10, the contact portions 66 of the respective cylinders 62 and 64 are spaced apart from the lower surface of the foot placement table 22 in a state where the foot placement table 22 is in the initial position. As shown in FIG. 12, in a state where the foot placement table 22 is in the lowered position, it is in contact with the lower surface of the foot placement table 22. The respective cylinders 62 and 64 can be individually extended and contracted by the control device 18. As shown in FIG. 13A, the second cylinder 64 is extended more than the first cylinder 62 to incline the front of the foot placement table 22 to be lower, or as shown in FIG. 13B, the first cylinder 62 is extended more than the second cylinder 62 to incline the rear of the foot placement table 22 to be lower.

[0066] In the sole force sensation presentation unit 12 provided with the inclination mechanism 60, when the user 90 walks with the foot placement table 22 inclined by the inclination mechanism 60, for example, the force sensation when walking on an inclined surface can be presented to the sole of the foot, or the force sensation when walking on a road surface with unevenness can be presented by changing the inclination state of the left and right sole force sensation presentation units 12. Thereby, in accordance with the images of various road surface conditions provided by the HMD 11, it is possible to provide variations in the force sensation during walking presented to the feet 92 of the user 90, and by synchronizing with the images of walking on an inclined surface or an uneven surface, a sense of reality as if walking on an actual inclined surface or uneven surface can be imparted while walking on the flat floor board 16.

[0067] Note that the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention.

[0068] For example, the lower limb force sensation presentation device 10 may have a configuration having a sole force sensation presentation unit 12 that presents a force sensation to the soles of the feet of the user 90 in synchronization with at least a falling image by the video display device, and may not have a leg force sensation presentation unit 14.

[0069] Further, the elevating mechanism 30 of the sole force sensation presentation unit 12 is not limited to being based on the pantograph structure unit 32, and may be a cylinder structure that extends and contracts in the vertical direction, or may be a ball screw that extends and contracts along a screw shaft that extends in the vertical direction.

[0070] In addition, the actuator serving as the drive source of the elevating mechanism 30 is not limited to the artificial muscle 40, and may be, for example, a fluid drive device such as an air cylinder or an oil cylinder, or an electric motor or the like.

[0071] Also, the braking unit that applies a braking force to the contraction operation of the elevating mechanism 30 is not limited to the MR fluid braking device, and may be, for example, an electrorheological fluid braking device using an electrorheological fluid whose viscosity changes when an electric field is applied. By using a functional fluid braking unit in which the functional fluid filled inside changes its viscosity by an external stimulus to adjust the braking force, such as MR fluid or electrorheological fluid, the braking force can be changed at high speed. Further, the braking unit is not limited to those using such a functional fluid, and may be, for example, an oil damper or an air damper.

[0072] Also, in the above-described embodiment, the magnetic force of the electromagnet 26 provided on the bottom 20 is used as the bottom fixing mechanism, but the bottom fixing mechanism is not limited to this, and may be, for example, a structure that fixes the bottom 20 to the floor surface by an adsorption force. In such a case, a plurality of suction holes may be provided on the upper surface of the floor board 16, and the bottom 20 of the plantar force sensation presentation unit 12 may be adsorbed and fixed to the floor surface by sucking air from the suction holes by a suction device built in the floor board 16.

[0073] Also, in the plantar force sensation presentation unit 12, the MR fluid braking unit 50, the tilting mechanism 60, and the bottom fixing mechanism are optional, and a structure without these may be used.

[0074] In addition, the lower limb force sensation presentation device 10 can be used not only for entertainment such as a game machine, but also, for example, as a device for training the danger prediction ability of workers performing work at high places or as a device for lower limb rehabilitation.

Explanation of reference numerals

[0075] 10 Lower limb force sensation presentation device 11 HMD 12 Plantar force sensation presentation unit 14 Foot force sensation presentation unit 16 Bed board 18 Control device 20 Bottom 22 Foot placement table 24 Wearable device 26 Electromagnet 30 Lifting mechanism 32 Pantograph structure part 40 Artificial muscle (actuator) 50 MR fluid braking part (braking part) 60 Tilting mechanism 62 First cylinder 64 Second cylinder 71 First frame 72 Second frame 74 Joint drive part 90 User

Claims

1. A lower limb force sensation presenting device that is used together with a video display device that provides visual information to a user and presents a force sensation to the lower limbs of the user, A pair of sole force sensation presenting parts configured to be attachable to the left and right feet of the user, A control part that controls the operation of the sole force sensation presenting part, Comprising: Each sole force sensation presenting part, A bottom part that forms a ground contact surface, A foot placement part that is provided above the bottom part and is attached to the foot in a state where the user's foot is placed thereon, A lifting mechanism that is disposed between the bottom part and the foot placement part and raises and lowers the foot placement part with respect to the bottom part, Comprising: The lifting mechanism, A pantograph structure part formed of links in a rhombus shape, with the lower end fixed to the bottom part and being stretchable and contractible in the vertical direction, An actuator connected to the pantograph structure part and stretching and contracting the pantograph structure part, Comprising: The pantograph structure part is provided in pairs on both the left and right sides of the bottom part of each sole force sensation presenting part, The actuator is an artificial muscle and is disposed between the paired pantograph structure parts, The control part controls the lifting mechanism so as to lower the foot placement part at a predetermined acceleration in synchronization with the timing at which a falling video is provided by the video display device. A lower limb force sensation presenting device characterized by this.

2. A lower limb force sensation presenting device that is used together with a video display device that provides visual information to a user and presents a force sensation to the lower limbs of the user, A pair of sole force sensation presenting parts configured to be attachable to the left and right feet of the user, A control part that controls the operation of the sole force sensation presenting part, Comprising: Each sole force sensation presenting part, A bottom part that forms a ground contact surface, A foot placement part that is provided above the bottom part and is attached to the foot in a state where the user's foot is placed thereon, A lifting mechanism that is disposed between the bottom part and the foot placement part and raises and lowers the foot placement part with respect to the bottom part, An inclination mechanism that is disposed between the bottom part and the foot placement part and inclines the foot placement part in the front-rear direction with respect to the bottom part, Comprising: The lifting mechanism, A pantograph structure part formed of links in a rhombus shape, with the lower end fixed to the bottom part and being stretchable and contractible in the vertical direction, An actuator connected to the pantograph structure part and stretching and contracting the pantograph structure part, Comprising: The inclination mechanism is provided respectively at the front part and the rear part of the bottom part and is formed in a columnar shape that is stretchable and contractible in the vertical direction, The lower limb force sensation presentation device is characterized in that the control unit controls the lifting mechanism to lower the foot placement part at a predetermined acceleration in synchronization with the timing at which the falling image is provided by the video display device.

3. In a lower limb force sensation presentation device that is used together with a video display device that provides visual information to a user and presents a force sensation to the lower limbs of the user, A pair of sole force sensation presentation parts configured to be wearable on the left and right feet of the user; A control unit that controls the operation of the sole force sensation presentation part; A floor board that forms a floor surface on which the user can walk while wearing the sole force sensation presentation part; A bottom fixing mechanism that can switch the bottom that forms the ground contact surface of each sole force sensation presentation part between a fixed state and a released state with respect to the floor board; Comprising: Each sole force sensation presentation part: A foot placement part provided above the bottom and worn on the foot in a state where the user's foot is placed; A lifting mechanism disposed between the bottom and the foot placement part, for raising and lowering the foot placement part with respect to the bottom; Comprising: The lifting mechanism: A pantograph structure part formed of links in a rhombus shape, with the lower end fixed to the bottom and being telescopable in the vertical direction; An actuator connected to the pantograph structure part for expanding and contracting the pantograph structure part; Comprising: The bottom fixing mechanism is built into the bottom and / or the floor board of the sole force sensation presentation part, The lower limb force sensation presentation device is characterized in that the control unit controls the lifting mechanism to lower the foot placement part at a predetermined acceleration in synchronization with the timing at which the falling image is provided by the video display device.

4. The actuator is an artificial muscle that expands and contracts in the axial direction due to a change in fluid pressure supplied inside a cylindrical elastic body, The lower limb force sensation presentation device according to claim 2 or 3, wherein the pantograph structure part expands and contracts in conjunction with the expansion and contraction operation of the artificial muscle.

5. The lower limb force sensation presentation device according to claim 1 or 3, further comprising an inclination mechanism disposed between the bottom and the foot placement part for inclining the foot placement part in the front-rear direction with respect to the bottom.

6. A floor board that forms a floor surface on which the user can walk while wearing the sole force sensation presentation part; A bottom fixing mechanism built into the bottom and / or the floor board of the sole force sensation presentation part, capable of switching the bottom between a fixed state and a released state with respect to the floor board; The lower limb force sensation presentation device according to claim 1 or 2, characterized by comprising the same.

7. The lifting mechanism according to any one of claims 1 to 6, characterized in that it comprises a braking part that applies a braking force to the contraction operation in a situation where the pantograph structure part contracts due to the user's own weight.

8. The lower limb force sensation presenting device according to claim 7, characterized in that the braking part is a functional fluid braking part capable of adjusting the braking force by changing the viscosity of a functional fluid filled inside due to an external stimulus.

9. Comprising a pair of exoskeleton-type leg force sensation presenting parts attached to the user's thighs and calves, Each leg force sensation presenting part, A first frame part attached to the thigh, A second frame part attached to the calf, And a joint drive part disposed between the lower end of the first frame part and the upper end of the second frame part for bending and extending the first frame part and the second frame part. The lower limb force sensation presenting device according to any one of claims 1 to 8, characterized in that the joint drive part bends or extends the first frame part and the second frame part in synchronization with the timing when visual information indicating that a force in the gravitational direction or the anti-gravitational direction acts on the user's legs is presented by the video display device.

10. A lower limb force sensation presenting method for presenting a force sensation together with a falling video by the video display device using the lower limb force sensation presenting device according to any one of claims 1 to 9, A step of lowering the foot placement part of the sole force sensation presenting part at a first acceleration in the initial stage of the fall, A step of decelerating the foot placement part from the first acceleration and stopping the descent during the fall, And a step of lowering the foot placement part at a second acceleration and then stopping the descent at the end of the fall.

Images