JP2009005764A - Rotary type actuator with damper function and operation assisting device using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary type actuator which can flexibly transmit the torque of a driving shaft to a driven shaft in a simple structure and whose damper effect is variable, and an operation assisting device using the same. <P>SOLUTION: The rotary type actuator with the damper function includes the driving shaft rotationally driven by a drive source, a pump impeller rotated integrally with the driving shaft, the driven shaft which is input to a system to be driven, a turbine impeller rotated integrally with the driven shaft, and a housing for housing fluid transmitting power from the pump impeller to the turbine impeller, the pump impeller and the turbine impeller, wherein the pump impeller and/or the turbine impeller is provided with a variable pitch mechanism. The operation assisting device using the same is also provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary actuator with a damper function and an operation assisting device using the same. Since the rotary actuator of the present invention has a damper function, it is particularly preferable to apply it to an operation assisting device for the elderly or the disabled.

  In recent years, research and development of robots that perform work on behalf of human beings have been actively conducted, and at the same time, research and development of devices that assist human physical ability or work ability are also progressing. This is a so-called robot suit or power assist suit. As such applications, it is considered to assist operations such as standing, sitting, walking, and stair climbing of a cared person as holding and transporting heavy objects, rehabilitation operations, or nursing equipment.

As an actuator used for these devices, a system using an electromagnetic motor, a pneumatic driving system, and a hydraulic driving system are employed. As a method of detecting the intention of the assistant, the muscle potential (also referred to as surface myopotential or bioelectric potential difference) generated according to the muscle tension of the assistant is detected, or the muscle hardness is pressured. A method of detecting with a sensor has been proposed (see, for example, Patent Document 1).
Furthermore, simpler auxiliary devices such as an auxiliary arm instead of a suit have been proposed (see, for example, Patent Documents 2 and 3). With the trend of longer life, the importance of such operation assisting devices is expected to increase further in the future.
JP 2004-105261 A JP-A-7-163607 JP 2007-29113 A

  An actuator used for such a motion assisting device is required to have an appropriate response to the user's intention. In particular, a device worn on the body of an assistant may cause danger if unexpected behavior is performed contrary to the intention of the assistant or if the person reacts sensitively. However, although it is ideal, it is quite difficult to realize the control of the assistance person's intention of movement from the outside accurately and instantaneously, and controlling it to react faithfully like his own muscle. Therefore, on the assumption that there is a slight difference between the intention of the assistant and the operation of the assisting device, it is preferable to provide a flexible assist operation that can be corrected by the power of the assistant himself / herself. That is, it is preferable that the power transmission unit has a damper function. On the other hand, in a scene where force is required, a device that can assist the person with sufficient force is desirable.

  In general, with a motor or a general hydraulic actuator, it is not allowed for the person being assisted to operate against the movement of the actuator. Pneumatic actuators have the advantage of flexibility, but their structure is complicated and not suitable for simple auxiliary equipment. Therefore, it is preferable to provide a damper function between a drive source such as a motor and the output unit.

  In the field of automobiles and the like, wet clutches and torque converters are known for absorbing power from a speed change mechanism and transmitting power flexibly. A torque converter drives fluid with a pump and extracts force with a turbine. However, pumps and turbine blades have a fixed pitch angle and cannot change their transmission characteristics. Further, if the rotation direction of the drive shaft is the same, the driven side also rotates only in a certain direction. Therefore, the mechanism of the torque converter cannot be applied as it is to the above-mentioned operation assisting device.

  The present invention has been made in consideration of the above-described circumstances, and is a rotary actuator capable of flexibly transmitting the torque of the drive shaft to the driven shaft with a simple structure and having a variable damper effect. And the operation assistance apparatus using the same is provided.

  The present invention relates to a drive shaft that is rotationally driven by a drive source, a pump impeller that rotates integrally with the drive shaft, a driven shaft that is an input to the system to be driven, and a turbine blade that rotates integrally with the driven shaft. And a housing for accommodating the pump impeller and the turbine impeller, wherein the pump impeller and / or the turbine impeller has a variable pitch mechanism. A rotary actuator with a damper function is provided.

  A base arm portion on which the actuator and the hinge portion are disposed; a slave arm portion that is rotatably attached to the hinge portion as an axis and rotates according to rotation of a driven shaft of the actuator; An operation assisting device comprising: a mounting portion for positioning a hinge portion of the actuator at a joint portion of a person; a drive source for driving a drive shaft of the actuator; and a pitch adjusting portion for adjusting a variable pitch mechanism of the actuator. provide.

  The actuator according to the present invention includes a fluid housing for transmitting power from the pump impeller to the turbine impeller, a housing for accommodating the pump impeller and the turbine impeller, and the pump impeller and / or the turbine impeller has a variable pitch mechanism. The torque of the drive shaft can be flexibly transmitted to the driven shaft with a simple structure. This is because the damper effect is caused by the viscosity of the fluid. In addition, the damper effect can be changed by the variable pitch mechanism.

  In addition, since the motion assisting device of the present invention includes the actuator and a pitch adjusting unit that adjusts the variable pitch mechanism of the actuator, it is possible to flexibly transmit the drive from the drive source, and further according to the operation of the person being assisted. The drive can be adjusted by adjusting the pitch of the pump impeller and / or turbine impeller.

  For example, the damping coefficient of the damper effect can be instantaneously changed to a value suitable for the assistance person's operation. In general, it is difficult to instantaneously change the rotation speed and direction of a motor that is a drive source of an actuator due to large inertia. However, the adjustment of the pitch angle of the pump impeller and / or turbine impeller according to the present invention is as follows. Compared to changing the rotation of the drive source, the inertia is small, and it can be quickly adjusted with a small force. Therefore, it is suitable for applications in which the speed, direction, and magnitude of force are instantaneously changed, such as human movement assistance.

Hereinafter, preferred embodiments of the present invention will be described.
In the actuator according to the present invention, the housing forms a flow path so that the fluid flows back from the pump impeller through the turbine impeller, and the variable pitch mechanism changes the pitch angle to rotate the driven shaft and / or Alternatively, the rotational torque may be changed.

  The pump impeller and the turbine impeller both have a variable pitch mechanism, and the variable pitch mechanism changes the damping characteristic of the damper function by interlocking the pitch angle of the pump impeller and the pitch angle of the turbine impeller. You may let them.

  An operation assisting device according to the present invention includes an operation intention detecting unit that detects an intention of an auxiliary person's operation, and a control unit that controls driving of the drive source and operation of the pitch adjusting unit according to the detected operation intention. May be further provided.

  The motion intention detection unit detects a muscle tension level that attempts to move the joint part or a biopotential difference that occurs when the joint part is moved, and the control unit detects a magnitude of the tension level or the biopotential difference. The pitch adjuster may be adjusted accordingly.

In addition, the control unit may adjust the pitch adjusting unit so that the damper effect is increased when the movement intention detecting unit detects that the assistant has applied force.
The various preferable aspects shown here can also be combined.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, the following description is an illustration in all the points, Comprising: It should not be interpreted as limiting this invention.

  FIG. 1 is an explanatory view showing the structure of a rotary actuator according to the present invention. In FIG. 1, the rotary actuator 1 is opposed to a drive shaft 13 directly connected to a shaft of a motor 11 that is a drive source, a pump impeller 17 that is at one end of the drive shaft and rotates with the drive shaft 13, and a pump impeller. And a driven shaft 43 that is a rotating shaft of the turbine impeller. The rotation of the driven shaft 43 is transmitted to the load via the output gear 41.

  The pump impeller 17 has variable blade pitch angles. The pitch angle of each blade changes as the clamp pin ring 18 rotates. The clamp pin ring is linked to one end of the push rod 19 inside the drive shaft 13. The other end of the push rod 19 is connected to a linear actuator 21, and the pitch angle of each blade is changed by the operation of the actuator 21. The pump impeller variable pitch mechanism as described above is also provided in the turbine impeller 47. In the turbine impeller 47, the pitch angle of each blade is changed by the operation of the actuator 51.

  The drive shaft 13, the pump impeller 17, the turbine impeller 47, and the driven shaft 43 are accommodated in the housing 31, and the housing 31 is filled with oil. A shield bearing 15 is provided between the housing 31 and the drive shaft 13. A shield bearing 45 is provided between the housing 31 and the driven shaft 43. Further, a shield bearing is also provided between the drive shaft 13 and the crank pin ring 18. A shield bearing is also provided between the crank pin ring of the turbine impeller 47 and the driven shaft 43. Therefore, the oil filled in the housing is in a sealed state, and an oil chamber 37 is formed inside the housing 31.

  The housing 31 is provided with an oil rectifying ring 33 and a support ring 35 that supports the rectifying ring 33. The support ring 35 is provided with an opening through which oil passes. When the pump impeller 17 rotates, the oil flows back in the direction of arrow F. Then, the turbine impeller 47 rotates by receiving the resistance of the oil flow, and the rotation of the drive shaft 13 is transmitted to the driven shaft 43. At this time, a damper effect due to oil viscosity occurs. Therefore, power transmission from the drive shaft 13 to the driven shaft 43 is performed flexibly.

  By changing the pitch angle of each blade of the pump impeller 17 and the pitch angle of each blade of the turbine impeller 47, the damper effect can be changed. Further, the rotational speed of the driven shaft 43 can be adjusted by changing the rotational speed of the motor 11.

  The shape of the housing 31 is preferably a smooth shape that does not impair the flow of oil. Therefore, a flow straightening ring 33 is disposed in the housing 31 to form a flow path so that the oil is efficiently circulated, thereby increasing the force transmission efficiency. A gear box may be attached between the motor 11 and the drive shaft 13 or between the driven shaft 43 and the load as necessary so that the shaft rotation speed is in an appropriate range.

  FIG. 2 is an explanatory diagram showing a variable pitch mechanism of the pump impeller 17 in this embodiment. As shown in FIG. 2, a push rod 19 is inserted into the drive shaft 13, and a head portion 23 is provided at the tip thereof. A groove portion is provided on the side wall of the head portion 23, and the groove portion is engaged with a pin portion 18 a provided on the crank pin ring 18 of one blade 17 a of the pump impeller 17. The push rod 19 moves in the direction of arrow A along with the operation of the linear actuator 21.

FIG. 3 is an explanatory diagram showing how the head portion 23 and the pin portion 18a according to the variable pitch mechanism are engaged in this embodiment. As shown in FIG. 3, the head portion 23 is a columnar member, and grooves 25a and 25b are provided around the side wall. The tip of the pin portion 18a of the blade 17a shown in FIG. 3 engages with the recess of the groove portion 25a. In addition, the groove part 25b is engaged with a pin part of another blade not shown in FIG. The periphery of the clamp ring 18 is attached to a shield bearing 27a (see FIG. 2) provided on the side of the drive shaft 13, and is rotatable in the direction of arrow P. The clamp ring 18 converts the reciprocating motion of the push rod rod 19 in the direction of arrow A into the rotational motion of the blade 17a in the direction of arrow P. The turbine impeller 47 also has a variable pitch mechanism similar to that shown in FIGS.
As the linear actuator 21, a small one for precision positioning using a motor as a drive source is known. A commercially available actuator may be used, or the mechanism may be diverted.

  The drive shaft 13, the driven shaft 43, the pump impeller 17, the turbine impeller 47, the housing 31, the rectifying ring 33, and the support ring 35 are made of metal, for example, an alloy containing iron, aluminum, magnesium, or titanium as a main component. Can be used. Moreover, you may apply the composite material containing carbon fiber etc. You may comprise combining those materials.

  FIG. 4 is an explanatory view showing an example of a motion assisting device provided with the rotary actuator of the present invention. FIG. 4 shows the mechanical configuration of the operation assisting device of the present invention. 4 is attached to the arm 70 of the person being assisted. However, the motion assist device provided with the rotary actuator of the present invention is not limited to this, and can be applied to a device for assisting the motion of joints of other parts, for example, the leg and waist, and the power assist suit described above. is there.

  In FIG. 4, the motion assisting device 71 is mainly composed of a base arm portion 73 having a hinge shaft 61 at one end and a slave arm portion 75 attached to the base arm portion 73 through the hinge shaft 61 so as to be rotatable. ing. The rotary actuator 1 and the motor 11 shown in FIG. 1 are attached to the base arm 73. The driven shaft 43 of the rotary actuator rotates the hinge shaft 61 as a load.

The sub arm portion 75 rotates integrally with the hinge shaft 61. As a material of the base arm portion 73 and the slave arm portion 75, a composite material including a resin, for example, a polyurethane resin, a polyamide resin, a fluororesin, a polyester resin, a carbon fiber, or a metal, for example, aluminum, magnesium, or titanium is a main component. These alloys can be used alone or in combination.
As the oil, commercially available oil for torque converter, silicone oil, and the like can be considered.

  Further, the base arm portion 73 is provided with a fixing belt 79a for mounting the base arm portion 73 on the arm 70 of the person being assisted, and a pressure sensor 77a for detecting muscle tension between the shoulder and the elbow of the arm 70. It has been. Although not shown in FIG. 4, a controller (control unit) that adjusts the pitch angle of the impeller of the motor 11 and the rotary actuator 1 based on the detection signal of the pressure sensor 77 a and the like is provided. The controller and motor 11 and linear actuators 21 and 51 are supplied with power from an external battery (not shown).

  The slave arm 75 is provided with a fixed belt 79b and a pressure sensor 77b. The fixing belts 79a and 79b function as a mounting portion in the claims. As the fixing belt, Velcro (registered trademark) or the like is applicable. The detection signal of the pressure sensor 77b is a sensor for detecting the tension of the muscle at the tip of the arm 70. Input to the controller in the base arm unit 73. The arrangement position and type of the sensor 77 are not limited to those illustrated in FIG. As described in the background art, various proposals have been made regarding the method for detecting the intention of the person being assisted, and it may be determined as appropriate according to the region and application. Each sensor functions as an action intention detection unit as defined in the claims.

  FIG. 5 is a block diagram mainly showing an example of the electrical configuration of the operation assisting device of the present invention. As shown in FIG. 5, the motion assisting device 71 of the present invention mainly includes a sensor 77, a controller 80, a motor drive unit 81, a motor 11 as a drive source, a rotary actuator 1, a drive shaft side linear actuator drive unit 83, and a follower. It consists of a shaft side linear actuator drive unit 84. The sensor 77 detects the tension of the muscle of the arm 70 of the assistant. In addition, in order to clearly indicate that the arm of the person being assisted is not included in the motion assisting device 71, the frame is indicated by a broken line.

  A detection signal from the sensor 77 is input to the controller 80. The controller 80 determines the movement of the person being assisted based on the detection signal. Based on the determination result, a motor control signal (instruction) is output to the motor drive unit 81. Further, control signals (instructions) for the actuators are output to the drive shaft side linear actuator drive unit 83 and the driven shaft side linear actuator drive unit 84, respectively. The motor drive unit 81 generates a drive signal corresponding to the control signal from the controller 80 and supplies it to the motor 11. As a result, the motor 11 operates at a rotation speed and a rotation direction according to instructions from the controller.

  Further, the linear actuators 21 and 51 operate according to respective instructions from the controller 80. Accordingly, each blade of the pump impeller 17 and the turbine impeller 47 is displaced to a pitch angle according to an instruction from the controller. As a result, the hinge shaft 61 is displaced with the driving force and the damper characteristic according to the determination result of the controller 80, and assists the person being assisted.

  For example, the controller 80 determines the movement of the assistance person based on the detection signal from the sensor 77 when the assistance person tries to apply a large force and tensions the muscle, such as when he / she has a heavy load. As a result, if it is determined that the assistant is trying to apply a large force, the controller 80 adjusts both the pitch angle of the pump impeller and the pitch angle of the turbine impeller to an angle that generates a large lift coefficient. .

  On the other hand, the controller 80 sets the pitch angle of the pump impeller and the pitch angle of the turbine impeller as described above when the assistant is trying to apply a relatively small force, such as when holding a light load compared to the above case. The angle is adjusted so as to generate a large lift-drag ratio compared to the case. As a result, power transmission efficiency from the drive source to the load is improved.

  Further, when the pitch angle of the turbine impeller is increased, the damping coefficient of the damper function is increased. Therefore, the controller 80 adjusts the pitch angle of the turbine impeller so that an appropriate attenuation coefficient is set according to the ability of the person being assisted. In order to determine an appropriate attenuation coefficient, the controller 80 inputs the ability of the person to be assisted to the person to be assisted himself or the administrator of the apparatus using an operation unit (not shown) before the operation assistance apparatus is used. You may let them. The operation unit may be provided integrally with the apparatus, or may be provided separately from the apparatus and connected to the apparatus as necessary so as to exchange signals with the controller 80. Also good.

  Here, when a shift occurs between the intention of the person being assisted and the movement of the motion assisting device, an external force is applied to the base arm portion 73 and / or the slave arm portion 75. As a result, the load torque of the driven shaft 43 changes via the hinge shaft 61. Although the rotational speed of the turbine impeller 47 changes according to the change of the load torque, a reaction force proportional to the amount of change of the additional torque is generated due to the viscosity of the oil. The proportionality coefficient depends on the pitch angle of the turbine impeller 47.

  As described above, when the rotary actuator according to the present invention is applied to the motion assisting device, it is allowed that the person being assisted operates against the movement of the actuator. Moreover, a reaction force proportional to the operation speed of the person being assisted is generated. In other words, it is possible to perform motion assist control that gives authority to a person without performing complicated sensing and control.

  In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

It is explanatory drawing which shows an example of the structure of the rotary actuator by this invention. In this embodiment, it is explanatory drawing which shows the variable pitch mechanism of a pump impeller. In this embodiment, it is explanatory drawing which shows the mode of engagement with the head part and pin part which concern on a variable pitch mechanism. It is explanatory drawing which shows an example of the operation assistance apparatus provided with the rotary actuator of this invention. It is a block diagram which shows an example of mainly an electrical structure of the operation assistance apparatus of this invention.

Explanation of symbols

1: Rotary actuator 11: Motor, drive source 13: Drive shaft 15, 27a, 27b: Shield bearing 17: Pump impeller 17a, 17b: Blade 18: Crank pin ring 18a: Pin portion 19: Push rod for pump impeller 21: Push rod actuator 23: Head portion 25a, 25b: Groove portion 31: Housing 33: Rectifying ring 35: Support ring 37: Oil chamber 41: Output gear 43: Drive shaft 45: Shield bearing 47: Turbine impeller 49: Turbine Impeller push rod 51: Push rod actuator 61: Hinge shaft, Drive load 70: Arm, Assisted person 71: Motion assist device 73: Base arm portion 75: Sub arm portions 77, 77a, 77b: Pressure sensor 79a, 79b: Mounting unit 80: Controller 81: Motor driving unit 83 Drive shaft side linear actuator driving unit 84: the side of the driven shaft linear actuator driving unit

Claims (7)

A drive shaft that is rotationally driven by a drive source;
A pump impeller that rotates integrally with the drive shaft;
A driven shaft that is an input to the system to be driven;
A turbine impeller that rotates integrally with the driven shaft;
A fluid that transmits power from the pump impeller to the turbine impeller, a housing that houses the pump impeller and the turbine impeller,
A rotary actuator with a damper function, wherein the pump impeller and / or the turbine impeller has a variable pitch mechanism. The housing forms a flow path so that the fluid flows back from the pump impeller through the turbine impeller,
The actuator according to claim 1, wherein the variable pitch mechanism changes the rotational direction and / or rotational torque of the driven shaft by changing the pitch angle. Both the pump impeller and the turbine impeller include a variable pitch mechanism,
The actuator according to claim 1, wherein the variable pitch mechanism changes a damping characteristic of a damper function by interlocking a pitch angle of a pump impeller and a pitch angle of a turbine impeller. A base arm portion on which the actuator and the hinge portion according to any one of claims 1 to 3 are disposed;
A slave arm portion pivotably attached to the hinge portion as an axis, and rotated according to the rotation of the driven shaft of the actuator;
A mounting part for positioning the hinge part of the actuator at the joint part of the person being assisted;
A drive source for driving the drive shaft of the actuator;
A motion assisting device comprising a pitch adjusting unit that adjusts a variable pitch mechanism of the actuator. An action intention detection unit for detecting the intention of movement of the assistant;
The motion assisting device according to claim 4, further comprising a control unit that controls driving of the drive source and operation of the pitch adjusting unit in accordance with the detected motion intention. The movement intention detection unit detects a muscle tension level that attempts to move the joint part or a biopotential difference that occurs when the joint part is about to move,
The operation assisting device according to claim 5, wherein the control unit adjusts the pitch adjusting unit according to the degree of tension or the bioelectric potential difference.   The motion assisting device according to claim 6, wherein the control unit adjusts the pitch adjusting unit so as to increase a damper effect when the motion intention detecting unit detects that the person being assisted has applied force.