JP2020091014A - Link operation device and original position decision method of link operation device - Google Patents

Abstract

To provide a link operation device in which a tip member can move on a spherical face with a spherical face link center point as a center, and a radius of the spherical face is adjustable, and which can perform the positioning of an original point of the tip member.SOLUTION: A link operation device comprises a base end member, a tip member, four or more link mechanisms, and four or more posture control drive sources. Each of the link mechanisms has a first link member rotatably connected to the base end member in a first rotation even part, a second link member rotatably connected to the first link member in a second rotation even part, a third link member rotatably connected to the second link member in a third rotation even part, and a fourth link member rotatably connected to the third link member in a fourth rotation even part, and rotatably connected to the tip member in a fifth rotation even part.SELECTED DRAWING: Figure 2

Description

The present invention relates to a link actuator and a method for locating the origin of the link actuator.

Japanese Patent Laid-Open No. 2000-94245 discloses a parallel link mechanism. US Pat. No. 5,893,296 discloses a link actuating device.

JP, 2000-94245, A US Pat. No. 5,893,296

In the parallel link mechanism described in Patent Document 1, it is necessary to lengthen each link in order to increase the operating range of the traveling plate because the operating angle of each link is small. As a result, the entire link mechanism becomes large. Further, if each link is lengthened, the rigidity of the entire link mechanism is reduced, and the weight of the tool mounted on the traveling plate (that is, the transportable weight of the traveling plate) is limited to a small value.

Since the link actuating device described in Patent Document 1 has a structure in which three or more sets of four-bar linkage are provided, it is possible to perform a precise operation in a wide operating range while having a compact structure. However, in the link actuating device described in Patent Document 2, due to its structure, the radius of gyration of the tip member changes according to the bending angle (the tip member does not move on the spherical surface), so it is difficult to imagine the operation. ..

Further, in the link actuating device described in Patent Document 2, the turning radius of the tip member cannot be adjusted. Further, in the link actuating device described in Patent Document 2, the positioning accuracy is deteriorated due to the looseness of the connecting portion of each link and the mechanism of the drive source.

The present invention has been made in view of the problems of the conventional techniques as described above. More specifically, according to the present invention, the tip member can move on a spherical surface centered on the spherical link center point, the radius of the spherical surface can be adjusted, and the origin of the tip member can be positioned. A possible link actuator is provided.

A link actuator according to an aspect of the present invention includes a base end member, a tip end member, four or more link mechanisms, and four or more attitude control drive sources. Each of the link mechanisms includes a first link member rotatably connected to the base end member at a first rotary pair portion, and a second link member rotatably connected to the first link member at a second rotary pair portion. A third link member that is rotatably connected to the second link member at the third rotation pair portion, and is rotatably connected to the third link member at the fourth rotation pair portion and at the tip member at the fifth rotation pair. And a fourth link member rotatably connected in the section. In each link mechanism, the first central axis, which is the central axis of the first rotating pair, and the second central axis, which is the central axis of the second rotating pair, intersect at the spherical link center point. The fifth central axes, which are the central axes of the fifth rotating pair parts in the respective link mechanisms, overlap each other and intersect the spherical link center point. The attitude control drive source is installed in at least four link mechanisms of the four or more link mechanisms, and is configured to rotate the first link member about the first central axis.

According to the above link actuator, the tip member can move on a spherical surface centered on the spherical link center point, the radius of the spherical surface can be adjusted, and the origin of the tip member can be positioned. Become.

The link actuating device may further include a recording medium. In this case, the parameters relating to the origin positioning can be recorded on the recording medium.

In the above link actuating device, in each link mechanism, the third central axis which is the central axis of the third rotating pair and the fourth central axis which is the central axis of the fourth rotating pair extend in directions parallel to each other. At the same time, it may extend in a direction orthogonal to the second central axis. In this case, the components of the link actuating device can be simplified.

In the above link actuating device, the number of link mechanisms may be four, and the number of attitude control drive sources may be four. In this case, a lightweight and compact link actuating device can be realized.

A method for locating an origin of a link actuating device according to an aspect of the present invention includes a step of constraining a posture of at least three link mechanisms out of four or more link mechanisms in the link actuating device described above, and a first link member. A step of applying a preload by applying a torque around the first central axis, a positional relationship between the first link member and the attitude control drive source in the preloaded state, Recording at least one of the rotation angle and the torque applied to the first link member on the recording medium.

According to the origin positioning method of the link actuator described above, the origin of the origin of the tip member of the link actuator can be adjusted while the tip member can move on a spherical surface centered on the spherical link center point and the radius of the spherical surface can be adjusted. It becomes possible to do.

According to the link actuating device and the origin positioning method of the link actuating device of the present invention, the tip member can move on a spherical surface centered on the spherical link center point, the radius of the spherical surface can be adjusted, and the tip member's radius can be adjusted. It is possible to position the origin.

3 is a schematic block diagram of the link operating device 10. FIG. 3 is a perspective view of the link operating device 10. FIG. 3 is a front view of the link operating device 10. FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. It is sectional drawing in VV of FIG. It is an example of a perspective view of the link operating device 10 in the restraint step. It is another example of the perspective view of the link actuating device 10 in the restraint step.

A link actuating device according to an embodiment (hereinafter, referred to as "link actuating device 10") will be described with reference to the drawings. In the following drawings, the same or corresponding parts will be denoted by the same reference symbols and redundant description will not be repeated.

(Configuration of Link Actuating Device According to Embodiment)
An example of the configuration of the link actuating device 10 will be described below.

FIG. 1 is a schematic block diagram of the link operating device 10. FIG. 2 is a perspective view of the link actuating device 10. FIG. 3 is a front view of the link actuating device 10. The link operating device 10 is provided with a recording medium 7 as shown in FIG. As the recording medium 7, it is possible to apply an appropriate configuration such as storing a program, a motor driver, or a scale. The recording medium 7 is connected to an attitude control drive source 4a to an attitude control drive source 4d described later.

As shown in FIGS. 2 and 3, the link actuator 10 is a spherical link actuator. The link actuating device 10 includes a base member 1, a tip member 2, a link mechanism 3a, a link mechanism 3b, a link mechanism 3c and a link mechanism 3d, an attitude control drive source 4a, an attitude control drive source 4b, and an attitude control. And a posture control drive source 4d. In this example, the number of link mechanisms and the number of attitude control drive sources are four, but the number of link mechanisms and the number of attitude control drive sources may be four or more. The number of link mechanisms and the number of attitude control drive sources are preferably four.

FIG. 4 is a sectional view taken along line IV-IV in FIG. FIG. 5 is a sectional view taken along line VV of FIG. As shown in FIGS. 2 to 5, the base end member 1 is a plate-shaped member. The planar shape of the base end member 1 is, for example, a circle. However, the planar shape of the base end member 1 is not limited to this. The base member 1 has a fixed portion 1a, a fixed portion 1b, a fixed portion 1c, and a fixed portion 1d on the outer peripheral portion. The fixed portions 1 a to 1 d are formed on the main surface of the base member 1. Each of the fixed portion 1a to the fixed portion 1d has a plate-like shape extending in the direction orthogonal to the main surface of the base member 1. A through hole 1e is formed in each of the fixed portions 1a to 1d. A through hole 1f is formed in the center of the base member 1.

The attitude control drive source 4a to the attitude control drive source 4d are, for example, motors. More specifically, each of the attitude control drive source 4a to the attitude control drive source 4d has a rotation shaft 4e and a drive source body 4f. The drive source body 4f is configured to rotationally drive the rotating shaft 4e around the central axis. The rotation shafts 4e of the posture control drive source 4a to the posture control drive source 4d are inserted into the through holes 1e of the fixed portions 1a to 1d, respectively.

Each of the link mechanisms 3a to 3d has a first link member 3e, a second link member 3f, a third link member 3g, and a fourth link member 3h.

The first link member 3e is, for example, a rod-shaped member that extends in an arc shape. The first link member 3e of each of the link mechanisms 3a to 3d is connected to the base end member 1 so as to be rotatable about the first central axis A1 in the first rotation pair part.

A through hole 3ea is formed at one end of the first link member 3e. The rotary shafts 4e of the attitude control drive source 4a to the attitude control drive source 4d are inserted into the through holes 3ea formed in the first link members 3e of the link mechanisms 3a to 3d, respectively. That is, the first rotating pair portion is configured by the through hole 3ea and the through hole 1e and the rotating shaft 4e inserted therein, and the first central axis A1 coincides with the central axis of the rotating shaft 4e. There is. As described above, the posture control drive source 4a to the posture control drive source 4d rotationally drive the rotation shaft 4e around its central axis (around the first central axis A1). Therefore, the attitude control drive source 4a to the attitude control drive source 4d rotationally drive the first link member 3e of the link mechanism 3a to the link mechanism 3d about the first central axis A1. The drop of the first link member 3e from the rotary shaft 4e is suppressed by attaching a nut or the like to the rotary shaft 4e.

A shaft portion 3eb is formed at the other end of the first link member 3e. The shaft portion 3eb is formed, for example, on the outer peripheral side surface of the first link member 3e. The shaft portion 3eb protrudes to the outside of the base end member 1 along the radial direction of the base end member 1.

The second link member 3f is, for example, a rod-shaped member that extends linearly. The second link member 3f of the link mechanism 3a to the link mechanism 3d is connected to the first link member 3e of the link mechanism 3a to the link mechanism 3c so as to be rotatable around the second central axis A2 in the second rotation pair portion. There is.

A through hole 3fa is formed at one end of the second link member 3f. The shaft portion 3eb formed at the other end of the first link member 3e of the link mechanism 3a to the link mechanism 3d is inserted into the through hole 3fa formed in the second link member 3f of the link mechanism 3a to the link mechanism 3d. .. That is, the second rotating pair portion is formed of the through hole 3fa formed at one end of the second link member 3f and the shaft portion 3eb formed at the other end of the first link member 3e, and the second The central axis A2 coincides with the central axis of the shaft portion 3eb. The drop of the second link member 3f from the shaft portion 3eb is suppressed by attaching a nut or the like to the shaft portion 3eb.

The first central axis A1 which is the central axis of the first rotational pair and the second central axis A2 which is the central axis of the second rotational pair intersect at the spherical link center point C of the link actuating device 10.

The third link member 3g is a rod-shaped member that extends linearly. The third link members 3g of the link mechanisms 3a to 3d are connected to the second link members 3f of the link mechanisms 3a to 3d so as to be rotatable around the third central axis A3 in the third rotation pair portion. There is.

A recess for receiving one end of the third link member 3g is formed at the other end of the second link member 3f. A through hole is formed at the other end of the second link member 3f. The through hole is formed at a position facing the recess. A through hole 3ga is formed at one end of the third link member 3g. The through hole formed at the other end of the second link member 3f and the through hole 3ga formed at the one end of the third link member 3g have a recess formed at the other end of the second link member 3f as a third link member. In a state where one end of 3 g is received, they are arranged linearly.

The connecting member 3gb is inserted through the through hole formed at the other end of the second link member 3f and the through hole 3ga formed at the one end of the third link member 3g. As a result, the third link member 3g is rotatably connected to the second link member 3f about the central axis of the connecting member 3gb. That is, the third rotating pair portion is formed of a through hole formed at the other end of the second link member 3f, a through hole 3ga formed at one end of the third link member 3g, and a connecting member 3gb, and 3 The central axis A3 coincides with the central axis of the connecting member 3gb. The connecting member 3gb is, for example, a bolt and a nut.

The fourth link member 3h of the link mechanism 3a to the link mechanism 3d is connected to the third link member 3g of the link mechanism 3a to the link mechanism 3d so as to be rotatable around the fourth central axis A4 in the fourth rotation pair portion. ing.

A through hole 3gc is formed at the other end of the third link member 3g. The fourth link member 3h is formed with a recess that receives the other end of the third link member 3g. The fourth link member 3h has a wall portion 3ha facing the recess. The wall portion 3ha is formed with a through hole connected to the recess. In the state where the above-mentioned recess receives the other end of the third link member 3g, the through hole formed in the wall portion 3ha and the through hole 3gc formed in the other end of the third link member 3g are arranged linearly. There is. The connecting member 3hb is inserted into the through hole formed in the wall portion 3ha and the through hole 3gc formed at the other end of the third link member 3g. As a result, the fourth link member 3h is rotatably connected to the third link member 3g about the central axis of the connecting member 3hb. That is, the fourth rotating pair portion is formed by the through hole formed in the wall portion 3ha, the through hole 3gc formed at the other end of the third link member 3g, and the connecting member 3hb, and the fourth central axis A4 is formed. It coincides with the central axis of the connecting member 3hb. The connecting member 3hb is, for example, a bolt and a nut.

It is preferable that the fourth central axis A4 of the fourth rotational pair portion is parallel to the third central axis A3 of the third rotational pair portion.

The fourth link member 3h of each of the link mechanisms 3a to 3d is connected to the tip member 2 rotatably around the fifth central axis A5 in the fifth rotation pair part.

The fourth link member 3h has a base portion 3hc. The planar shape of the base portion 3hc is circular. A through hole is formed in the center of the base portion 3hc. The base portions 3hc of the link mechanisms 3a to 3d are laminated so that the through holes overlap each other. When viewed from the link mechanism 3a, the link mechanism 3b to the base portion 3hc of the link mechanism 3d are combined to form the tip member 2, and when viewed from the link mechanism 3b, the link mechanism 3a, the link mechanism 3c, and the base portion of the link mechanism 3d. 3 hc are combined to form the tip member 2. Similarly, when viewed from the link mechanism 3c, the link mechanism 3a, the link mechanism 3b, and the base portion 3hc of the link mechanism 3d are combined to form the tip end member 2. When viewed from the link mechanism 3d, the link mechanism 3a to the link mechanism 3c. The base portions 3hc of the above are combined to form the tip member 2. The connecting member 3hd is inserted into the through hole formed in the center of the base portion 3hc. The connecting member 3hd is, for example, a bolt and a nut. A through hole 3he is formed in the connecting member 3hd along the direction of the central axis of the connecting member 3hd.

As a result, the fourth link members 3h of the link mechanisms 3a to 3d are connected to the tip member 2 so as to be rotatable around the central axis of the connecting member 3hd. That is, the fifth rotating pair portion is configured by the through hole formed in the base portion 3hc of the link mechanism 3a to the link mechanism 3d and the connecting member 3hd, and the fifth central axis A5 is aligned with the central axis of the connecting member 3hd. I am doing it. The fifth rotating pair is arranged so as to overlap at one place.

The fifth central axis A5 of the fifth rotational pair portion overlaps with each other and intersects the first central axis A1 of the first rotational pair portion and the second central axis A2 of the second rotational pair portion at the spherical link center point C. There is. The fifth central axis A5 of the fourth rotating pair is twisted with the third central axis A3 of the third rotating pair and the fourth central axis A4 of the fourth rotating pair. The fifth central axis A5 is preferably orthogonal to the third central axis A3 and the fourth central axis A4.
(Operation of Link Actuating Device According to Embodiment)
The operation of the link operating device 10 will be described below.

In the link operating device 10, the spherical link center is changed by changing the rotation angles of the first link member 3e of the link mechanism 3a to the link mechanism 3d about the first central axis A1 by adopting the above-described configuration. The tip member 2 moves on a spherical surface centered on the point C. That is, the position of the tip member 2 can be represented by polar coordinates (r, θ, φ) with the spherical link center point C as the origin.

Here, the center-to-center distance r is the distance between the spherical link center point C and the center of the tip member 2. The bending angle θ is a fifth straight line passing through a point where a straight line that is vertically lowered from the center of the tip member 2 intersects with a plane including the first central axis A1 of the link mechanisms 3a to 3d and a spherical link center point C. It is an angle formed by the central axis A5. The swivel angle φ is defined by a straight line that descends from the center of the tip member 2 in the vertical direction and a point that intersects with a plane including the first central axis A1 of the link mechanisms 3a to 3d and a spherical link center point C, and the link mechanism. 3a is an angle formed by the first central axis A1.

As described above, in the link actuating device 10, the tip end member 2 is movable on the spherical surface having the radius r centered on the spherical link center point C and the center-to-center distance r, and independently of the movement. By moving the tip member 2 along the central axis A5, the center-to-center distance r can be made variable. In this way, the link operating device 10 can move the tip member 2 with a total of three degrees of freedom.

(Origin Positioning Method of Link Actuating Device According to Embodiment)
The origin positioning method of the link operating device 10 will be described below.

In the origin positioning of the link actuating device 10, firstly, a restraining step of restraining at least three postures of the link mechanism 3a to the link mechanism 3d is performed. FIG. 6 is an example of a perspective view of the link actuating device 10 in the restraining step. As shown in FIG. 6, in the restraining step, for example, the origin positioning shaft 5 is inserted into the through hole 3he formed in the connecting member 3hd and the through hole 1f formed in the center of the base member 1 and the origin positioning is performed. This is done by attaching bolts, stoppers, etc. to the shaft 5 for use.

However, the restraining step may be performed by another method. FIG. 7 is another example of a perspective view of the link operating device 10 in the restraining step. As shown in FIG. 7, in the restraint step, the restraint block 6 that restrains the rotation of the first link member 3e of the link mechanism 3a to the link mechanism 3d around the first central axis A1 is arranged on the base end member 1. May be performed by.

In the origin positioning of the link actuating device 10, secondly, a preloading step of preloading the link mechanisms 3a to 3d is performed. The preload process is performed in a state where the postures of the link mechanism 3a to the link mechanism 3d are restricted. The preloading step is performed, for example, by applying a torque around the first central axis A1 to the first link member 3e of the link mechanism 3a to the link mechanism 3d by the attitude control drive source 4a to the attitude control drive source 4d. The application of the torque may be performed using, for example, a heavy object as long as the preload can be controlled.

In positioning the origin of the link operating device 10, thirdly, the positional relationship between the first link member and the attitude control drive source (the positional relationship between the first link member 3e of the link mechanism 3a and the attitude control drive source 4a, The positional relationship between the first link member 3e of the link mechanism 3b and the attitude control drive source 4b, the positional relationship between the first link member 3e of the link mechanism 3c and the attitude control drive source 4c, and the first link member of the link mechanism 3d. 3e and the position control drive source 4d), the rotation angle of the first link member 3e of the link mechanism 3a to the link mechanism 3d around the first central axis A1, or the first link member of the link mechanism 3a to the link mechanism 3d. The torque applied to 3e is output.

The output of these parameters is performed in a state in which the torque around the first central axis A1 is applied to the first link members 3e of the link mechanisms 3a to 3d. The output of these parameters is performed using the encoder provided in the attitude control drive source 4a-the attitude control drive source 4d, for example. The output parameters are stored in the recording medium 7. In the link operating device 10, by reflecting these parameters in the operation of the link operating device 10, the origin of the tip member 2 can be positioned.

(Effects of Link Actuating Device According to Embodiment)
The effects of the link operating device 10 will be described below.

As described above, in the link operating device 10, the radius centered on the spherical link center point C is movable on the spherical surface having the center-to-center distance r, and independently of the movement, along the fifth central axis A5. The center-to-center distance r can be made variable by moving the tip member 2 by means of the above.

In the link operating device 10, the tip end member 2 has three degrees of freedom, but the number of attitude control drive sources and the number of link mechanisms are four or more. Therefore, in the link actuating device 10, not only the tip member 2 can be moved with three degrees of freedom, but also the tip member 2 can be preloaded, and vibration and shake of the tip member 2 can be suppressed.

In the link actuating device 10, the third central axis A3 of the third rotating pair and the fourth central axis A4 of the fourth rotating pair extend in directions parallel to each other and in a direction orthogonal to the second central axis A2. If so, the components of the link actuating device can be simplified.

In the link actuating device 10, when the number of link mechanisms and the number of attitude control drive sources are four, a lightweight and compact link actuating device can be realized.

Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified. Further, the scope of the present invention is not limited to the above embodiment. The scope of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

The embodiments described above are particularly advantageously applied to spherical link work devices.

C spherical link center point, A1 first center axis, A2 second center axis, A3 third center axis, A4 fourth center axis, A5 fifth center axis, 1 base end member, 1a, 1b, 1c, 1d fixed part 1e through hole, 1f through hole, 2 tip member, 3a, 3b, 3c, 3d link mechanism, 3e first link member, 3ea through hole, 3eb shaft part, 3f second link member, 3fa through hole, 3g third Link member, 3ga through hole, 3gb connecting member, 3gc through hole, 3h Fourth link member, 3ha wall part, 3hb, 3hd connecting member, 3hc base part, 3he through hole, 4a, 4b, 4c, 4d Attitude control drive Source, 4e Rotation axis, 4f Drive source main body, 5 Origin positioning shaft, 6 Restraint block, 7 Storage medium, 10-link operating device.

Claims (5)

A base member,
A tip member,
4 or more link mechanisms,
With four or more attitude control drive sources,
Each of the link mechanisms includes a first link member that is rotatably connected to the base end member at a first rotation pair part, and a second link member that is rotatably connected to the first link member at a second rotation pair part. A link member, a third link member rotatably connected to the second link member at a third rotation pair portion, a third link member rotatably connected to the third link member at a fourth rotation pair portion, and the tip. A fourth link member rotatably connected to the member at a fifth rotating pair,
In each of the link mechanisms, a first central axis that is a central axis of the first rotating pair and a second central axis that is a central axis of the second rotating pair intersect at a spherical link center point.
Fifth central axes, which are central axes of the fifth rotating pair parts in each of the link mechanisms, overlap each other and intersect with the spherical link center point,
The attitude control drive source is installed in at least four of the four or more link mechanisms, and is configured to rotate the first link member about the first central axis. The link actuator. The link operating device according to claim 1, further comprising a recording medium. In each of the link mechanisms, a third central axis that is a central axis of the third rotating pair and a fourth central axis that is a central axis of the fourth rotating pair extends in parallel directions, and The link actuating device according to claim 2, which extends in a direction orthogonal to the two central axes. The number of the link mechanisms is four,
The link actuating device according to claim 2 or 3, wherein the number of drive sources for attitude control is four. The link actuation device according to any one of claims 2 to 4,
Restraining the posture of at least three of the four or more link mechanisms,
Preloading by applying torque to the first link member around the first central axis;
In the state where the preload is performed, the positional relationship between the first link member and the attitude control drive source, the rotation angle of the first link member around the first central axis, or the first link member is applied. And recording at least one of the torques on the recording medium.