JP4838576B2 - Flexible actuator - Google Patents

Description

  The present invention relates to a flexible actuator, and is particularly suitable for a flexible actuator that transmits a driving force of a direct drive motor to an object to be driven.

  One of the actuators used in robots is one that uses a direct drive motor. Robots using direct drive motors include hand robots and forceps robots. A rotary type or linear type direct drive motor is a motor that has little friction and is suitable for force transmission, and has an advantage that force can be transmitted to an object to be driven without a transmission mechanism such as a gear. Conventionally, a drive system using a wire or a drive system using a rod has been used for a transmission mechanism of a direct drive motor. JP-A-2003-311667 (Patent Document 1) is given as a related prior art.

JP 2003-31667 A

  Since the rod drive has high rigidity, it has excellent force transmission characteristics, but there is a problem that the degree of freedom of the installation position of the actuator is low due to lack of flexibility.

  Further, since the wire drive has flexibility, the actuator can be freely arranged spatially, but there is a problem that the force cannot be transmitted with high accuracy because of low rigidity. Furthermore, the wire drive has a problem that it can be pulled but cannot be pushed.

  An object of the present invention is to provide a flexible actuator capable of accurately transmitting a bidirectional force acting on a drive target from the direct drive motor while allowing the direct drive motor and the drive target to be arbitrarily arranged spatially. It is to provide.

In order to achieve the above object, a first aspect of the present invention includes a linear direct drive motor that generates an axial driving force, and a thrust that transmits the axial driving force of the direct drive motor to an object to be driven. The thrust wire includes a cylindrical outer member having flexibility, and is disposed in the outer member so as to be movable in the axial direction and has rigidity in the axial direction. An inner member higher than the rigidity in the vertical direction, and both ends of the inner member are coupled to the direct drive motor and the driven object, and the inner member is covered with a synthetic resin fiber, The outer member is covered with a polymer .

  According to a second aspect of the present invention, there is provided a rotary direct drive motor that generates a driving force in the axial rotation direction, and a torque wire that transmits the driving force in the axial rotation direction of the direct drive motor to a drive target. The torque wire has a cylindrical outer member having flexibility, and is arranged in the outer member so as to be able to rotate about the shaft and has rigidity in a direction perpendicular to the shaft. It is comprised by the double structure which consists of a higher inner member, and it exists in the both ends of the said inner member being couple | bonded with the said direct drive motor and the said drive object.

A more preferable specific configuration example in the first aspect of the present invention is as follows.
(1) The inner member is formed by coating a polyamide fiber on a metal core wire such as stainless steel, and the outer member is formed by a three-layer structure in which a hard steel wire is coated with a synthetic resin and further covered with a polyethylene tube. is being done.
A more preferable specific configuration example in the second aspect of the present invention is as follows.
(1) The inner member is covered with a synthetic resin fiber, and the outer member is covered with a polymer.
(2) The inner member is formed by coating a polyamide fiber on a metal core wire such as stainless steel, and the outer member is formed by a three-layer structure in which a hard steel wire is coated with a synthetic resin and further covered with a polyethylene tube. is being done.
The third aspect of the present invention includes a linear direct drive motor that generates an axial driving force, and a thrust wire that transmits the axial driving force of the direct drive motor to a drive target, The thrust wire has a cylindrical outer member having flexibility, and is arranged in the outer member so as to be movable in the axial direction, and the rigidity in the axial direction is higher than the rigidity in the direction perpendicular to the axis. The inner member has a double structure, and both end portions of the inner member are coupled to the direct drive motor and the object to be driven, and the displacement of the direct drive motor is directly controlled regardless of the behavior of the inner member. in that it comprises an encoder which measures.
A more preferable specific configuration example in the third aspect of the present invention is as follows.
( 1 ) An encoder for measuring the displacement of the drive target is provided.

  According to the flexible actuator of the present invention, the direct drive motor and the drive target can be arbitrarily arranged spatially, and the bidirectional force acting on the drive target can be accurately transmitted from the direct drive motor. .

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The flexible actuator of 1st Embodiment of this invention is demonstrated using FIGS. 1-3. FIG. 1 is a perspective view showing the overall configuration of the flexible actuator of the present embodiment, FIG. 2 is an explanatory view of a thrust wire used in the present embodiment, and FIG. 3 is an example of a force control result using the flexible actuator of the present embodiment. FIG. 2A is an overall view of the thrust wire, FIG. 2B is a view showing a single inner member of the thrust wire, and FIG. 2C is a view showing a single outer member of the thrust wire.

  As shown in FIG. 1, the flexible actuator includes a linear direct drive motor 101 that generates an axial driving force, and a thrust wire 102 that transmits the axial driving force of the direct drive motor 101 to a drive target 103. It is configured with. That is, the direct drive motor 101 transmits a driving force to the driving target 103 by the thrust wire 102 to drive the driving target 103. Further, the force applied to the drive target 103 is transmitted to the direct drive motor 101 by the thrust wire 102.

  As shown in FIG. 2, the thrust wire 102 has a cylindrical outer member 201 having flexibility, and is disposed in the outer member 201 so as to be movable in the axial direction and has rigidity in the axial direction. Is composed of a double structure composed of an inner member 203 having higher rigidity in a direction perpendicular to the axis.

  The inner member 203 is covered with a synthetic resin fiber, and the outer member 201 is covered with a polymer. Specifically, the inner member 203 is formed by coating a stainless steel core wire with a synthetic fiber such as a polyamide fiber. The outer member 201 has a three-layer structure in which a hard steel wire is coated with a synthetic resin and further covered with a polyethylene tube. With such a configuration, the inner member 203 has high rigidity in the axial direction, and can reduce friction of the outer member 201 while having flexibility in a direction orthogonal to the axis. The thrust wire 102 can accurately transmit the force in both directions when pushing or pulling.

  Here, the outer diameter of the inner member 203 is as large as possible within a range smaller than the inner diameter of the outer member 201 and within a range in which the frictional force with the outer member 201 is within an allowable range under the condition of the bending curvature of the inner member 203. It is desirable. Further, metal fittings 202 and 204 are attached to the inner member 203 for attachment, and they are attached to the direct drive motor 101 and the drive target 103 respectively. In the illustrated example, male screw portions are formed at the ends of the fittings 202 and 204 for mounting, and these screw portions are screwed into and coupled to the female screw portions of the direct drive motor 101 and the drive target 103.

  By using the flexible actuator having the above-described configuration, the direct drive motor 101 and the drive target 103 can be freely arranged freely in space. Although FIG. 1 shows an example in which the direct drive motor 101 and the drive target 103 are connected by the thrust wire 102 having an angle of approximately 180 degrees, the direct drive motor 101 and the drive target 103 can be arranged at other angles and positional relationships.

  In this embodiment, as shown in FIG. 1, the linear encoder 104 measures the displacement of the direct drive motor 101, the linear encoder 105 measures the displacement of the drive target 103, and the force sensor 106 is applied to the drive target 103. Configured to measure force. By using these measured values for controlling the direct drive motor 101, the controllability can be further improved. At this time, since the linear encoder 104 is mounted so that the displacement of the direct drive motor 101 can be directly measured, the displacement feedback control of the direct drive motor 101 is effective without being influenced by the thrust wire 102.

FIG. 3 shows an example of the result of force control of the drive target 103 by the direct drive motor 101 in such a flexible actuator. As can be seen from FIG. 3, the force (response) 302 applied to the drive target 103 is in good agreement with the force control command value 301. That is, by using the flexible actuator according to the present embodiment, the thrust wire 102 maintains high rigidity without losing flexibility, so that the direct drive motor 101 and the drive target 103 can be freely and freely arranged spatially. In addition to the advantage of being able to arrange, the force transmission characteristics are excellent, the force acting between the drive target 103 and the direct drive motor 101 is bidirectional, less friction, good frequency characteristics, accurate There is an effect that can be communicated.
(Second Embodiment)
Next, the flexible actuator of 2nd Embodiment of this invention is demonstrated. The second embodiment is different from the first embodiment in the points described below, and the other points are basically the same as those in the first embodiment, and thus redundant description is omitted.

  In the first embodiment, the force is transmitted in the axial direction of the thrust wire 102, but in the second embodiment, the torque is transmitted in the axial rotation direction. That is, in the second embodiment, a rotary direct drive motor is used instead of the direct drive motor 101, and a torque wire is used instead of the thrust wire 102. Specifically, the flexible actuator according to the second embodiment includes a rotary direct drive motor that generates a driving force in the axial rotation direction, and a torque wire that transmits the driving force in the axial rotation direction by the direct drive motor to a drive target. And is configured. This torque wire has a flexible cylindrical outer member, and is arranged so as to be axially rotatable in the outer member with flexibility, and the rigidity in the axial rotation direction is higher than the rigidity in the direction perpendicular to the axis. It is comprised by the double structure which consists of an inner member.

  In the second embodiment, in addition to the advantage that the direct drive motor and the drive target can be freely arranged freely and spatially, the torque transmission characteristics are excellent, and the direct drive motor and the drive target are arranged between the drive target and the direct drive motor. Torque acting in both directions can be transmitted accurately in both directions with low friction and good frequency characteristics.

It is a perspective view showing the whole flexible actuator composition of a 1st embodiment of the present invention. It is explanatory drawing of the thrust wire used for this embodiment. It is a figure which shows an example of the force control result using the flexible actuator of this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Direct drive motor, 102 ... Thrust wire, 103 ... Drive object, 104, 105 ... Linear encoder, 106 ... Force sensor, 201 ... Outer member, 202, 204 ... Metal fitting, 203 ... Inner member, 301 ... Force control command value 302: Force applied to the driven object.

Claims (6)

A linear direct drive motor that generates an axial driving force, and a thrust wire that transmits the axial driving force of the direct drive motor to a drive target;
The thrust wire is a cylindrical outer member having flexibility, and is disposed in the outer member so as to be movable in the axial direction, and the rigidity in the axial direction is perpendicular to the axis. It is composed of a double structure consisting of a higher inner member,
Both ends of the inner member are coupled to the direct drive motor and the drive object ,
The inner member is covered with a synthetic resin fiber, and the outer member is covered with a polymer ;
A flexible actuator characterized by A rotary direct drive motor that generates a driving force in the axial rotation direction, and a torque wire that transmits the driving force in the axial rotation direction by the direct drive motor to a drive target;
The torque wire includes a cylindrical outer member having flexibility, and is arranged in the outer member so as to be capable of rotating in the shaft, and the rigidity in the shaft rotation direction is higher than the rigidity in the direction perpendicular to the shaft. It is composed of a double structure consisting of a high inner member,
Both end portions of the inner member are coupled to the direct drive motor and the drive target;
A flexible actuator characterized by The flexible actuator according to claim 2 , wherein the inner member is covered with a synthetic resin fiber, and the outer member is covered with a polymer. 4. The inner member according to claim 1 , wherein the inner member is made of a metal core wire such as stainless steel coated with a polyamide fiber, and the outer member is made of a hard steel wire coated with a synthetic resin and further covered with a polyethylene tube. A flexible actuator comprising a layered structure. A linear direct drive motor that generates an axial driving force, and a thrust wire that transmits the axial driving force of the direct drive motor to a drive target;
The thrust wire is a cylindrical outer member having flexibility, and is disposed in the outer member so as to be movable in the axial direction, and the rigidity in the axial direction is perpendicular to the axis. It is composed of a double structure consisting of a higher inner member,
Both ends of the inner member are coupled to the direct drive motor and the drive object,
An encoder that directly measures the displacement of the direct drive motor regardless of the behavior of the inner member;
A flexible actuator characterized by   The flexible actuator according to claim 5, further comprising an encoder that measures a displacement of the drive target.

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