JPH11303804A - Actuator using functional fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator capable of being high speedily and sophiscatedly controlled by using a functional fluid as an operating fluid. SOLUTION: An actuator is provided with a cylinder 2 filled an electric viscous fluid 94, a piston 4 for dividing the cylinder 2 into a first and a second parts 21, 22 an electrode pair for acting an electric field on the electric viscous fluid 94, and a motor 7 for pressurizing or depressurizing the electric viscous fluid 94. Furthermore, the actuator has a control part, thereby the movement of the piston 4 is controlled on the basis of a pressure acting on the electric viscous fluid 94 by the motor 7 and the change of viscosity of the electric viscous fluid 94 caused by acting the electric field.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator using a functional fluid whose viscosity changes by electromagnetic energy as a working fluid.

[0002]

2. Description of the Related Art As an actuator using a working fluid, a hydraulic actuator is generally used in many cases. This hydraulic actuator transmits pressure from a motor, a pump, or the like, which is a pressure source, to a piston disposed in a cylinder via oil, which is a working fluid, to move the piston.

Then, in order to reciprocate the piston,
A valve mechanism is provided for switching the direction of pressure transmitted from the pressure source to the piston.

As this valve mechanism, a plurality of solenoid valves are usually used in combination, and the moving direction of the piston can be switched by controlling the opening and closing of each solenoid valve.

[0005]

However, such a conventional hydraulic actuator cannot respond to the operation of a motor or a pump driven at a high speed because the reaction speed of the solenoid valve is low. There is a problem that high-speed and fine-grained control cannot be performed.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an actuator capable of performing high-speed and fine-grained control by using a functional fluid as a working fluid. Aim.

[0007]

SUMMARY OF THE INVENTION The present invention provides a cylinder filled with a functional fluid whose viscosity changes by electromagnetic energy, a piston dividing the cylinder into first and second portions, and a functional fluid. Energy generating means for applying electromagnetic energy to, and pressure generating means for pressurizing or depressurizing the functional fluid, an actuator comprising: a pressure change acting on the functional fluid by the pressure generating means, Control means is provided for controlling the movement of the piston based on the change in the viscosity of the functional fluid by the energy generating means.

In such a configuration, when electromagnetic energy is applied to the functional fluid from the energy generating means, the viscosity of the applied portion changes. When the viscosity of the functional fluid increases, the flow resistance of the portion increases and the flow becomes difficult to flow. Conversely, when the viscosity decreases, the flow resistance of the portion decreases and the flow becomes easy. Thereby, the pressure applied to the piston from the pressure generating means via the functional fluid is controlled, and the movement of the piston is controlled.

The control means operates the energy generating means in synchronization with the operation of the pressure generating means.

In such a configuration, when the pressure generating means pressurizes or depressurizes the functional fluid, the energy generating means operates in synchronization with the operation to control the moving direction of the piston.

Further, the actuator according to the present invention detects a pressure applied to the functional fluid at a first portion of the cylinder and a pressure sensor applied to the functional fluid at a second portion of the cylinder. And a second pressure sensor, wherein the control means controls the energy generating means based on the outputs of the first and second pressure sensors.

With such a configuration, the first and second pressure sensors detect an external force applied to the piston, and move the piston in a direction in which the external force acts.
The operation of the energy generating means is controlled by the control means.

The pressure generating means and the cylinder are connected to each other via a pipe smaller than the cylinder, and an energy generating means is arranged in the pipe.

In such a configuration, when the viscosity of the functional fluid in the pipe is changed by the energy generating means,
Since the flow resistance of the functional fluid in the pipe changes, the pressure acting on the piston from the pressure generating means via the functional fluid changes. The change in the pressure acting on the piston controls the movement of the piston.

[0015] Further, the pipe comprises a first pipe connecting the first portion of the cylinder and the pressure generating means, and a second pipe of the cylinder.
And a second pipe communicating with the pressure generating means, and a third pipe communicating with both the pipes, and the energy generating means is arranged in each of the first to third pipes.

In such a configuration, the moving direction of the piston is changed by switching the energy generating means to be operated from among the energy generating means arranged in each of the first to third pipes.

Further, the piston has a through-hole communicating the first and second portions, and energy generating means.

In such a configuration, when the viscosity of the functional fluid in the through-hole is increased by the energy generating means, the functional fluid pressurized by the pressure generating means becomes difficult to pass through the through-hole. Moves in the direction of pressure and reduces viscosity, the functional fluid becomes
Since the piston easily passes through the through hole, the piston is stationary or the movement is reduced.

Further, the actuator according to the present invention includes a position sensor for detecting a position of the piston, and the control unit controls the piston to reach a target position based on an output of the position sensor.

Further, the pressure generating means and the cylinder are connected to each other via a pipe smaller than the cylinder, and the piston is
There is provided a through-hole communicating the first and second portions, and energy generating means.

Further, a first pipe connecting the first portion of the cylinder and the pressure generating means, a second pipe connecting the second portion of the cylinder and the pressure generating means, and a third pipe connecting the two pipes. And an energy generating means is arranged in the third pipe.

In such a configuration, when the energy from the energy generating means is controlled, the pressure acting on the piston from the pressure generating means changes. For this reason, when an external force is acting against the movement direction of the piston, the energy generation means is controlled so that the viscosity of the functional fluid increases, and the piston reaches the target position.

Specifically, the functional fluid is an electrorheological fluid whose viscosity is increased by applying an electric field, and the energy generating means is an electrode pair sandwiching the electrorheological fluid.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. (First Embodiment) In this embodiment, a case will be described in which the actuator of the present invention is applied to an upper limb movement assisting device.

FIG. 1 is a perspective view showing a schematic configuration of an upper limb movement assisting device according to the present embodiment, FIG. 2 is a sectional view showing a schematic configuration of an actuator mounted on the upper limb assisting device,
FIG. 3 is a block diagram showing a control system of the actuator, and FIG.
6 are explanatory diagrams of the operation of the actuator device, FIG. 7 is a table showing a relationship between a driving direction of the motor in a standby state of the actuator and a voltage application state in each electrode, and FIG. FIG. 9 is a table showing the relationship between the voltage and the voltage application state of each electrode.
8 shows a table showing the relationship between the driving direction of the motor and the voltage application state at each electrode in the shortened operation state of the actuator.

In FIG. 1, reference numeral 1 denotes a multi-degree-of-freedom support mechanism having a free end at one end, and a fixing portion 14 which can be fixed at an arbitrary position is provided at an end opposite to the free end. I have.

The multi-degree-of-freedom support mechanism 1 includes an L-shaped support 11
And a turning arm 13 attached to one end of the support 11 via a bearing 12. The rotation arm 13 is rotatable in a horizontal plane by interposing the bearing 12 between the support arm 11 and the support arm 11.

The multi-degree-of-freedom support mechanism 1 is a slider (not shown) slidable on the lower surface of the rotating arm 13.
And an actuator 16 suspended by the slider via a ball joint 15. By interposing a slider between the actuator 16 and the rotating arm 13, the actuator 16 can slide in the longitudinal direction of the rotating arm 13, and the ball joint 15 can be interposed between the actuator 16 and the rotating arm 13. Thereby, it is possible to turn around the ball joint 15.

Further, the multi-degree-of-freedom support mechanism 1 includes a wrist brace 17 attached to the tip of the actuator 16, and the wrist brace 17 is mounted near the wrist of the assisted person.

The operation of the actuator is controlled by electric power supplied from the control unit 8 (see FIG. 3) in the control box 18 and a drive signal.

In FIG. 1, the plate 9 placed on the table 91 is
2. The helper is carrying the food on 2 with a spoon 93 to the mouth. At this time, for movement in the horizontal plane, the upper limb can be moved with relatively little force, but a large force is required in the vertical direction,
The driving force of the actuator 16 assists the vertical movement of the upper limb.

As shown in FIG. 2, the actuator 16 includes a tubular cylinder 2 and a piston 4 disposed in the cylinder 2 and dividing the cylinder 2 into a first portion 21 and a second portion 22. ing. The piston 4 has
One end of the piston rod 41 is fixed, and the wrist orthosis 17 shown in FIG. 1 is attached to the other end of the piston rod 41.

The cylinder 2 is filled with an electrorheological fluid 94, a first pressure sensor 31 is provided in a first portion 21, and a second pressure sensor 31 is provided in a second portion 22. Is provided. Then, the liquid pressure of the electrorheological fluid 94 in the first portion 21 of the cylinder 2 is measured by the first pressure sensor 31 and the second pressure sensor 3
2, the hydraulic pressure of the electrorheological fluid 94 in the second part 22 is measured.

The actuator 16 has a first pipe 51 having one end communicating with the first portion 21 of the cylinder 2 and the other end communicating with a first compression chamber 77 of the motor 7 provided as pressure generating means. And one end of the second part 2 of the cylinder 2
2 and a second pipe 52 having the other end communicating with the second compression chamber 78 of the motor 7, and a second pipe 52 having one end communicating with the first pipe 61 and the other end communicating with the second pipe 62. And a third pipe 63.

The first to third pipes 51, 52, 53 are filled with an electrorheological fluid 94 in the same manner as the cylinder 2.
First to third electrode pairs 61, 62, and 63 are provided as energy generating means so as to sandwich the electrorheological fluid 94 therebetween. Here, since the electrorheological fluid 94 is a fluid having a property of increasing viscosity according to the strength of an electric field to be applied, a voltage is applied by applying a voltage to the electrode pairs 61, 62 and 63. The flow resistance of the part which has been increased increases, making it difficult for the electrorheological fluid 94 to flow.

On the other hand, the motor 7 pressurizes the first driving piston 72 for pressurizing or depressurizing the electrorheological fluid 94 in the first compression chamber 77 and pressurizes the electrorheological fluid 94 in the second compression chamber 78. Alternatively, a second driving piston 73 for reducing the pressure is provided, and the first and second driving pistons 72 and 73 are integrated. A magnet 74 is attached to central portions of the integrated first and second driving pistons 72 and 73, and a ring-shaped first ring is provided around the magnet 74 so as to surround the magnet 74. And a second electromagnet 75,
76 are juxtaposed.

When the first electromagnet 75 is energized,
The magnet 74 is attracted to the first electromagnet 75 side,
The electrorheological fluid 94 in the compression chamber 77 is pressurized by the first driving piston 72, and the electrorheological fluid 94 in the second compression chamber 78 is depressurized by the second driving piston 73. Conversely, when the second electromagnet 76 is energized,
The electrorheological fluid 94 in the compression chamber 77 is depressurized, and the electrorheological fluid 94 in the second compression chamber 78 is pressurized.

Next, the control system of the actuator 16 will be described below with reference to the block diagram of FIG.

In the figure, the control unit 8 reads the external force from the assisted person detected by the first and second pressure sensors 31 and 32 disposed on the cylinder 2 at a predetermined cycle, and reads the first and second external force. The operation timing of the two electromagnets 75 and 76 is detected by detecting the drive current of the two electromagnets 75 and 76. Then, the control unit 8 controls the first to third electrode pairs based on the relationship between the outputs of the pressure sensors 31 and 32 and the operating electromagnets 75 and 76 stored in advance in a built-in memory (not shown). 61, 62,
Select which electrode pair in 63 to apply the voltage to.

The selected electrode pair includes both electromagnets 75, 7
6, a predetermined voltage is applied in synchronism with the operation timing, and the flow resistance of that portion is increased, so that the electrorheological fluid 94
Is regulated. That is, the pipe to which the voltage is applied is
It is as if the valve was closed. The operation principle of the actuator 16 having such a configuration will be described below with reference to FIGS.

In FIG. 3, the first electromagnet 7
When power is supplied to 5, the driving pistons 72 and 73 move in the direction of arrow B1. At this time, the control unit 8 detects the current supplied to the electromagnet 75 and synchronizes with the first and second electrode pairs 61,
Voltage is applied to 62. In this case, the first compression chamber 7
The electrorheological fluid 94 pressurized at 7 hardly flows on the first pipe 51 side toward the high-viscosity cylinder 4, but flows on the low-viscosity third pipe 63 side (arrow B2). 3
The second compression chamber 78 of the motor 7 (arrow B)
Flow into 3). Therefore, even if the driving piston of the motor 7 moves in the direction of arrow B1, the piston 4 remains stationary (hereinafter, referred to as operation B).

Conversely, when the first electromagnet 76 of the motor 7 is energized, the driving pistons 72, 73 move in the direction of arrow A1. At this time, the control unit 8 detects the current supplied to the electromagnet 76 and applies a voltage to the first and second electrode pairs 61 and 62 in synchronization with the timing of detecting the current. . In this case, the electrorheological fluid 94 pressurized in the second compression chamber 78 hardly flows to the second pipe 52 side toward the high-viscosity cylinder 4 and the third low-viscosity third fluid
Flows toward the pipe 63 (arrow A2) of the third pipe 63
, And flows into the first compression chamber 77 (arrow A3) of the motor 7. Therefore, even if the driving pistons 72 and 73 of the motor 7 move in the direction of the arrow A1, the piston 4 remains stationary (hereinafter, referred to as operation A).

In FIG. 5, when the first electromagnet 75 of the motor 7 is energized, the driving pistons 72 and 73 move in the direction of arrow C1. At this time, the controller 8 controls the electromagnet 7
The voltage applied to the third electrode pair 63 is detected by detecting the current flowing through the fifth electrode pair 5 in synchronization with the timing at which the current is detected. In this case, the electrorheological fluid 94 pressurized in the first compression chamber 77 is supplied to the high viscosity third pipe 6.
The flow hardly flows to the third side and flows into the first portion 21 (arrow C2) of the cylinder 2 via the first pipe 51 having low viscosity, and the piston 4 moves in the direction of arrow C4. Then, the electrorheological fluid 94 pressurized in the second portion 22 of the cylinder 2
Is connected to the second compression chamber 7 of the motor 7 through the second pipe 52.
8 (arrow C3). Accordingly, when the driving piston of the motor 7 moves in the direction of arrow C1, the piston 4 moves in the direction of arrow C4 (hereinafter, referred to as operation C).

In FIG. 7, when the second electromagnet 76 of the motor 7 is energized, the driving pistons 72 and 73 move in the direction of arrow D1. At this time, the controller 8 controls the electromagnet 7
The voltage applied to the third electrode pair 63 is detected by detecting the current flowing through the third electrode pair 63 in synchronization with the timing at which the current is detected. For this reason, the electrorheological fluid 94 pressurized in the second compression chamber 78 is supplied to the third viscous third pipe 6.
The flow hardly flows to the third side, flows into the second portion 22 of the cylinder 2 through the second pipe 52 having low viscosity (arrow D2), and the piston 4 moves in the direction of arrow D4. Then, the electrorheological fluid 94 pressurized in the first portion 21 of the cylinder 2
Is connected to the first compression chamber 7 of the motor 7 through the first pipe 51.
7 (arrow D3). Therefore, when the driving pistons 72 and 73 of the motor 7 move in the direction of arrow D1, the piston 4 moves in the direction of arrow D4 (hereinafter, referred to as operation D).

By appropriately combining the operations A to D, the piston 4 is moved in a predetermined direction.

More specifically, as shown in the table of FIG. 7, when the operation A and the operation B are repeated, the piston 4 does not move in the operation A and the operation B, and enters a standby state.

As shown in the table of FIG. 8, when the operation C and the operation B are repeated, the piston 4 moves in the operation C and the piston 4 does not move in the operation B.
The piston 4 is repeatedly moved in the direction of arrow C4 in FIG.

Further, as shown in the table of FIG. 9, when the operation D and the operation A are repeated, the piston 4 moves in the operation D and the piston 4 does not move in the operation A.
The piston 4 is repeatedly moved in the direction of arrow D4 in FIG.

The arrows C4 and D4 are in opposite directions.

Therefore, in the present embodiment, since the electrorheological fluid 94 is used as the working fluid, the speed is high and the
The operation of the piston 4 can be controlled finely.

Further, even when the actuator 16 is disconnected or malfunctions, the operation of the actuator 16 is not fixed. Therefore, when the actuator 16 is applied to a device mounted on a human body such as an upper limb motion assisting device. Can improve safety.

In the present embodiment, the motor 7
Since the voltage is applied to the electrode pairs 61, 62 and 63 in synchronization with the operation described above, the variation in the movement amount of the piston 4 is small, and the movement of the piston 4 can be controlled precisely.

Further, in the present embodiment, the pressure sensor 31 is provided on the first and second portions 21 and 22 of the cylinder 2.
Since the external force 32 is provided to detect the external force acting on the piston 4 and control the operation of the piston 4 based on the external force, it can be used without discomfort when worn on a human body.

In this embodiment, the case where the actuator 16 is applied to the upper limb assist device has been described. However, the present invention is not limited to this, and may be applied to various devices including a robot arm. .

In the present embodiment, the support 11
Although the bearing 12 is interposed between the rotating arm 13 and the rotating arm 13, a motor may be interposed to control the driving of the motor so that the rotating arm 12 is always at the optimum position. . (Second Embodiment) In the first embodiment, the case where the electrode pairs 61, 62, 63 are provided in the pipes 51, 52, 53 communicating with the cylinder 2, respectively, has been described. In the description, a case where the electrode pair 161 is provided on the piston 140 will be described. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

FIG. 10 is a sectional view showing a schematic configuration of the actuator 116 in the present embodiment.

As shown in FIG.
Has a tubular cylinder 2 and a piston 140 arranged in the cylinder 2 and dividing the cylinder 2 into a first part 21 and a second part 22. Piston 14
0, one end of the piston rod 41 is fixed,
At the other end of the piston rod 41, the wrist orthosis 1 shown in FIG.
7 is attached.

The piston 140 has a through hole 141 communicating between the first and second parts 21 and 22 of the cylinder 2,
An electrode pair 161 for applying a voltage to the electrorheological fluid 94 in the through hole 141 is provided. Here, since the electrorheological fluid 94 is a fluid having a characteristic of increasing viscosity according to the strength of an electric field to be applied, by applying a voltage to the electrode pair 161, the flow of the portion to which the voltage is applied is increased. The resistance increases, making it difficult for the electrorheological fluid 94 to flow.

The actuator 116 has a first pipe 151 having one end communicating with the first portion 21 of the cylinder 2 and the other end communicating with a first compression chamber 177 of the motor 7 provided as pressure generating means. And one end thereof communicates with the second portion 22 of the cylinder 2, and the other end thereof communicates with the second compression chamber 78 of the motor 7.
And a second pipe 152 communicating with the second pipe 152.

In the first and second pipes 151 and 152,
As with the cylinder 2, it is filled with an electrorheological fluid 94.

In such a configuration, the driving force of the motor 170 is transmitted through the link mechanism 172 to the driving piston 171.
, Whereby the piston 171 reciprocates at a predetermined cycle.

When the piston 171 is driven in the direction of the arrow E1, the controller 8 applies a voltage to the electrode pair 161 in synchronization with the operation of the piston 171. In this case, the electrorheological fluid 94 pressurized in the first compression chamber 177 hardly passes through the through hole 141 of the piston 140,
40 is moved in the direction of arrow E2 (hereinafter, referred to as operation E).

Conversely, when the piston 171 is driven in the direction of the arrow F1, the controller 8 applies a voltage to the electrode pair 161 in synchronization with the operation of the piston 171. In this case, the electrorheological fluid 94 pressurized in the second compression chamber 178 is
The piston 140 is moved in the direction of the arrow F2 without substantially passing through the through hole 141 of the piston 140 (hereinafter, referred to as operation F).

When no voltage is applied to the electrode pair 161, the functional fluid passes through the through hole 141 regardless of the driving direction of the driving piston 171, so that the piston 141 does not move (hereinafter, operation G). ).

When the operations E and G are repeated,
In operation E, the piston 140 moves, and in operation G, the piston 140 does not move.
0 is repeatedly moved in the direction of arrow E in FIG.
When the operation F and the operation G are repeated, the piston 140 moves in the operation F, and the piston 140 moves in the operation G.
Does not move, the piston 140 moves in the direction indicated by the arrow F in FIG.
Moved repeatedly in the direction.

Therefore, in this embodiment, since the through hole 141 and the electrode pair 161 are provided in the piston 140, it is only necessary to control the voltage applied to one set of the electrode pair 161. Thus, the configuration of the actuator 116 is simplified, and the size can be reduced. Furthermore,
The control of the electrode pair 116 by the control unit 8 is also simplified, and the load on the control unit 8 can be reduced. (Third Embodiment) In the second embodiment, the case where the electrode pair 161 is provided on the piston 140 has been described. However, in this embodiment, the motor 290 and the bidirectional pump 271 are used as pressure generating means. The case where the position sensor 233 is provided along the longitudinal direction of the cylinder 2 and the position of the piston 4 is controlled based on the position sensor 233 will be described. In this embodiment, the same components as those of the first or second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 11 is a sectional view showing a schematic configuration of an actuator 216 according to the present embodiment.

As shown in FIG.
Has a position sensor 233 along the longitudinal direction of the cylinder 2, and the position sensor 233 detects the position of the piston 4.

The actuator 216 has one end communicating with the first portion 21 of the cylinder 2, the other end communicating with a bidirectional pump 271 provided as a pressure generating means, and one end having the second end with the cylinder 2. The second pipe 2 communicates with the second section 22 and the other end communicates with the bidirectional pump 271.
52 and a third pipe 2 communicating with both pipes 251 and 252.
53.

The bidirectional pump 271 is driven by a motor 290. An air layer 254 filled with air is communicated with the first pipe 251 and performs a buffer function when a sudden external force acts on the piston 4. An electrode pair 261 is arranged in the third pipe 253.

Then, the first to third pipes 251 and 25
2, 253, like the cylinder 2, the electrorheological fluid 9
4 are filled.

Next, the control system of the actuator 216 will be described below with reference to the block diagram of FIG.

In the figure, the control unit 8 reads the external force from the assisted person detected by the first and second pressure sensors 31 and 32 disposed on the cylinder 2 at a predetermined period, and reads the external force from the position sensor 233. By detecting the position of the piston 4 at a predetermined cycle, a target position for moving the piston 4 is determined. Then, the control unit 8 controls the pump 27
A control signal for controlling the pressing direction and a voltage applied to the electrode pair 261 are output.

When the voltage applied to the electrode pair 261 is increased, the fluid resistance increases according to the magnitude of the voltage, and the flow of the electrorheological fluid 94 is regulated. Therefore, electrode pair 2
By controlling the voltage applied to 61, the piston rod 41
Is controlled. When the voltage applied to the electrode pair 261 is sufficiently increased, the electrorheological fluid 94 hardly flows in that portion, and the valve is closed.

In this configuration, when the motor 290 is driven and the bi-directional pump 271 pressurizes the electrorheological fluid 94 in the direction of arrow H1, the piston 4 moves in the direction H2 according to the pressure. Here, when a voltage is applied to the electrode pair 261, the flow resistance of the electrorheological fluid 94 flowing through the third pipe 253 increases, so that the pressure acting on the piston 4 increases.

Conversely, when the motor 290 is driven and the bi-directional pump 271 pressurizes the electrorheological fluid 94 in the direction of arrow J1, the piston 4 moves in the direction J2 according to the pressure. Here, when a voltage is applied to the electrode pair 261, the third
Since the flow resistance of the electrorheological fluid 94 flowing through the pipe 253 increases, the pressure acting on the piston 4 increases.

Therefore, by controlling the magnitude of the voltage applied to the electrode pair 261, the actuator 216 can be driven while controlling the viscoelasticity.

In this embodiment, the first to third pipes 251, 252, 253 are provided,
By providing the electrode pair 261 in the pipe 253, the actuator 216 is driven while controlling the viscoelasticity. However, the present invention is not limited to this.

For example, as shown in FIG.
Through hole 1 communicating between the first and second portions 21 and 22
The viscoelasticity is controlled by controlling the magnitude of the voltage applied to the electrode pair 161 by using the piston 140 having the electrode 41 and the electrode pair 161 for applying the voltage to the functional fluid in the through hole 141. Alternatively, the actuator 316 may be configured to be driven.

In each of the embodiments described above, the electrorheological fluid 94 whose viscosity changes by an electric field is used as the working fluid. However, the working fluid is not limited thereto.
A functional fluid such as a magnetic fluid whose viscosity changes by a magnetic field may be used. In this case, a coil or the like can be used as the energy generating means.

[0081]

According to the present invention, since the functional fluid is used as the working fluid of the actuator, it can be operated at high speed and
It becomes possible to control the movement of the piston finely.

Further, even if the actuator is disconnected or broken down, the operation of the actuator is not fixed. Therefore, when applied to a device mounted on a human body such as an upper limb motion assist device, It is possible to improve safety.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a schematic configuration of an upper limb motion assisting device according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of an actuator mounted on the upper limb motion assisting device of FIG.

FIG. 3 is a block diagram illustrating a control system of the actuator of FIG. 2;

FIG. 4 is an explanatory diagram illustrating an operation of the actuator of FIG. 2;

FIG. 5 is an explanatory diagram illustrating an operation of the actuator of FIG. 2;

FIG. 6 is an explanatory diagram illustrating an operation of the actuator of FIG. 2;

FIG. 7 is a table showing a relationship between a driving direction of a motor and a voltage application state of each electrode in a standby state.

FIG. 8 is a table showing a relationship between a driving direction of a motor and a voltage application state of each electrode in an extension operation.

FIG. 9 is a table showing a relationship between a driving direction of a motor and a voltage application state of each electrode in a shortening operation.

FIG. 10 is a sectional view illustrating a schematic configuration of an actuator according to a second embodiment.

FIG. 11 is a sectional view illustrating a schematic configuration of an actuator according to a third embodiment.

FIG. 12 is a block diagram illustrating a control system of the actuator of FIG.

FIG. 13 is a cross-sectional view illustrating a schematic configuration of an actuator according to a fourth embodiment.

[Explanation of symbols]

 16: Actuator 2: Cylinder 31: First pressure sensor 32: Second pressure sensor 4: Piston 41: Piston rod 51: First pipe 52: Second pipe 53: Third pipe 61: First Electrode pair 62: Second electrode pair 63: Third electrode pair 7: Motor 8: Control unit 94: Electro-rheological fluid

Claims (10)

[Claims] 1. A cylinder filled with a functional fluid whose viscosity changes by electromagnetic energy, a piston dividing the cylinder into first and second portions, and applying electromagnetic energy to the functional fluid. An energy generating means for generating pressure and a pressure generating means for pressurizing or depressurizing the functional fluid, wherein a change in pressure acting on the functional fluid by the pressure generating means, and the energy generating means An actuator comprising: control means for controlling the movement of the piston based on a change in the viscosity of the functional fluid caused by the above. 2. The actuator according to claim 1, wherein the control means operates the energy generating means in synchronization with the operation of the pressure generating means. 3. A first pressure sensor for detecting a pressure applied to the functional fluid at a first portion of the cylinder, and a second pressure sensor for detecting a pressure applied to the functional fluid at a second portion of the cylinder. 3. The actuator according to claim 1, further comprising: a pressure sensor, wherein the control unit controls the energy generation unit based on outputs of the first and second pressure sensors. 4. 4. The pressure generating means and the cylinder,
The actuator according to any one of claims 1 to 3, wherein the actuator is connected to the cylinder via a pipe thinner than the cylinder, and the energy generating means is arranged in the pipe. 5. The pipe according to claim 1, wherein the first pipe connects the first part of the cylinder and the pressure generating means, and the second pipe connects the second part of the cylinder and the pressure generating means. 5. The actuator according to claim 4, further comprising a third pipe communicating with the two pipes, wherein the energy generating unit is disposed in each of the first to third pipes. 6. 6. The apparatus according to claim 1, wherein the piston includes a through-hole communicating the first and second portions, and the energy generating unit. Actuator. 7. The apparatus according to claim 1, further comprising a position sensor for detecting a position of the piston, wherein the control unit controls the piston to reach a target position based on an output of the position sensor. 2. The actuator according to 1. 8. The pressure generating means and the cylinder,
8. The piston according to claim 7, wherein the piston is provided with a through hole communicating with the first and second portions, and the energy generating means is connected to the cylinder via a pipe thinner than the cylinder. 9. Actuator. 9. A first pipe connecting the first portion of the cylinder and the pressure generating means, and a second pipe of the cylinder.
And a second pipe connecting the pressure generating means,
The actuator according to claim 7, further comprising a third pipe communicating with the two pipes, wherein an energy generating unit is disposed in the third pipe. 10. The method according to claim 1, wherein the functional fluid is an electrorheological fluid whose viscosity is increased by applying an electric field, and the energy generating means is an electrode pair sandwiching the electrorheological fluid. Item 10. The actuator according to any one of Items 1 to 9.