JP2008232197A - Guide rail stopper mechanism of three-degree-of-freedom rotation system and application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a singular point at which rotation of a rotor becomes uncontrollable without using a complicated mechanism such as an actuator, in a three-degree-of-freedom rotation system. <P>SOLUTION: In the three-degree-of-freedom rotation system 100 provided with a first guide rail 11 and second and third guide rails 12, 13 which are vertical to the first guide rail 11, a female type stopper 72 having a recessed part 72c is provided for either one of the second guide rail 12 or the third guide rail 13 and a male type stopper 71 is provided for the other guide rail. As the male type stopper 71 slides in the recessed part 72c and contacts either one of ends of the recessed part 72c, sliding movement of the male type stopper 71 is limited and thus difference of rotation angles of the second guide rail 12 and the third guide rail 13 is limited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a guide rail stopper mechanism for restricting a movable range of a guide rail of a three-degree-of-freedom rotation system using at least three guide rails, and an application thereof.

The three-degree-of-freedom rotation system shown in Patent Document 1 has a spherical bearing structure, attaches at least three guide rails to two orthogonal axes, and slides the indicator bar and the slider along a slit or the like provided in the guide rail. Thus, the rotor can be rotated with three degrees of freedom. As shown in Patent Document 1, this system has many uses. For example, when used for a robot joint, compared to a conventional system that requires three joints to rotate with three degrees of freedom, Since the distance between the point supporting the force and the point applying the force can be shortened, there is an advantage that the moment of inertia can be reduced. In addition, since the center of rotation is one, free and smooth movement can be achieved compared to the case of using three joints. When an external force is applied to the robot arm, the external force is applied in the direction in which the external force is most easily received. There is also an advantage that a small and lightweight three-degree-of-freedom robot joint that can be freely transferred and is safe even if it comes into contact with the human body is realized.
International Publication No. WO / 2004/011824 Design Registration No. 1214569

  Although the conventional three-degree-of-freedom rotation system has such excellent characteristics, the conventional three-degree-of-freedom rotation system has a singular point where the rotor cannot be rotated depending on the position of the slider. ing. Specifically, the straight line connecting the slider and the indicator rod is perpendicular to the guide rail for interacting with the slider, and the rotation of the rotor becomes uncontrollable. For this reason, it has been necessary to constantly monitor the rotation angle of two guide rails attached to the same shaft member and control the rotation of the guide rail with an actuator so that the slider does not reach a singular point.

  That is, it is necessary to constantly monitor the rotation angles of the second and third guide rails attached to the same shaft member, and to control the rotation of the guide rail with an actuator or the like so that the slider does not reach a singular point. . For this reason, there has been a problem that the structure becomes complicated. There is no particular problem when used for applications that do not require a large force such as artificial eyeballs, but when used for applications that require a large force such as robots, a powerful actuator is required, complicating and increasing the size of the device. was there.

  Therefore, the present invention avoids a singular point where the rotation of the rotor becomes uncontrollable in a three-degree-of-freedom rotation system without using a complicated mechanism such as an actuator, and simplifies the structure of the three-degree-of-freedom rotation system. The purpose is to do.

  In order to achieve the above object, the present invention is an invention as described in claims 1 to 5.

  The present invention attaches these guide rails to the base so that one guide rail and the remaining two guide rails are orthogonal to each other, and an indicator rod attached to the rotor and at least one indicator rod attached to the indicator rod The slider detects the orientation of the rotor by rotating these guide rails while sliding along these guide rails, and rotates the rotor by rotating these guide rails by an actuator. The system includes a guide rail stopper mechanism for restricting the movable range of the guide rail. Further, the present invention is a three-degree-of-freedom rotation system provided with the guide rail stopper mechanism and a robot joint that rotates with three degrees of freedom realized by the three-degree-of-freedom rotation system provided with the guide rail stopper mechanism.

  In Claims 1 to 5, if the rotation of the male stopper can be limited by the female stopper, the shape of the female stopper and the male stopper is not limited. The female stopper and the male stopper may be attached to the guide rail with screws or the like, but are preferably formed integrally with the guide rail. The rotor and the indicator rod, and the indicator rod and the arm are fixed so as not to rotate. However, the arm and the slider may be fixed or rotatably attached. It may be integrally formed from the indicator bar to the slider.

  The “nested shape” as defined in claim 4 has a similar structure (similar shape etc.) to the second guide rail and the third guide rail, and one guide rail is larger than the other guide rail. A structure in which the bearing of one guide rail is disposed outside the shaft member and the bearing of the other guide rail is disposed inside the shaft member is formed on the shaft member that is formed and supports them.

  According to the first aspect of the present invention, the difference between the rotation angles of the second guide rail and the third guide rail is limited by the guide rail stopper mechanism, so that the angle between the arm and these guide rails is 90 degrees. Can be reached. This eliminates the need for a mechanism that constantly monitors the rotation angle of the second guide rail and the third guide rail and restricts the rotation angle using an actuator, thus simplifying the structure and realizing a compact, lightweight, and inexpensive system. can do.

  In addition, there are the following advantages compared to the case where the actuator is limited as in the prior art. The first advantage is that stopping with the stopper provided on the guide rail stops rotation from the center of the shaft rather than stopping with the shaft member by an actuator or the like to stop the force applied to the guide rail ( Using the radius up to the point where the female stopper and the male stopper are in contact), the lever can be stopped with a small force. Even if a large external force is applied to the guide rail, the singular point can be physically avoided by the stopper regardless of the torque of the actuator, so that the singular point can be reliably avoided. Compared with the case where the shaft is stopped by the shaft member, the stopper provided on the guide rail can be stopped near the point where the force can be applied. Therefore, there is an advantage that the guide rail is hardly distorted.

  Secondly, if the stopper is provided on the guide rail, the structure becomes simple and easy to process. Third, it is easier to machine a highly accurate positioning system because it is less likely to cause a rotation angle error when it is stopped at a guide rail with a larger radius than when it is stopped at the shaft part (having a radius close to zero). This is a possible point.

  In addition, when actually used in a robot joint or the like, the angle between the second guide rail and the arm is often only about 60 degrees on both sides around the second guide rail. Not only can the points be avoided, but the range of the rotation angle can also be limited to a desired range according to the application.

  According to the invention described in claim 2, since the female stopper and / or the male stopper is formed integrally with the second and / or third guide rail, a large force is applied to the guide rail. The stopper is hard to break.

  According to the third aspect of the present invention, a three-degree-of-freedom rotation system having the same effect as that of the first or second aspect can be realized.

  According to the invention of claim 4, since the second guide rail and the third guide rail are attached in a nested manner, the area where the second guide rail provided with the stopper and the third guide rail overlap. Becomes larger. Therefore, even if these guide rails have no special shape or additional parts, the radius to stop rotation, that is, the distance from the center of the rotating shaft to the point where the female stopper and male stopper contact each other Can be made large, and the selection range of the recess width is also widened.

  According to the fifth aspect of the present invention, the three-degree-of-freedom rotation system according to the third or fourth aspect is used for the robot joint and is attached to the tip of the robot arm, thereby overcoming the problem of singularity. A multi-degree-of-freedom robot arm with a small moment of inertia can be created. The fact that the moment of inertia is small has, of course, the advantage that a smaller actuator may be used to generate the same force on the robot joint.

  In addition, when an external force is applied to the robot arm, the external force is most easily received by taking advantage of the characteristics of the three-degree-of-freedom rotation system that allows the slider to rotate to three degrees of freedom until the slider is limited by the stopper. The tip of the robot arm can be moved smoothly in the direction. Furthermore, even when the stopper becomes effective, it can continue to receive external force around the remaining rotating shaft. Since the external force can be passed in this way, by using the invention according to claim 5, it is possible to realize a small and light three-degree-of-freedom robot joint that is safe even if it comes into contact with the human body.

  Hereinafter, a preferred embodiment of a three-degree-of-freedom rotation system 100 including a guide rail stopper mechanism 7 according to the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the basic structure of the three-degree-of-freedom rotation system 100 is a spherical bearing structure in which a spherical rotor 1 and a base 2 penetrated in a partially spherical shape are combined. The outer shape of the base 2 may be arbitrary, but the central portion of the base 2 is formed in a partial spherical shape in accordance with the contact surface of the rotor 1, and each of the frictions between the rotor 1 and the base 2 is minimized. The contact surface shall be machined.

  The indicator rod 3 is attached to the rotor 1 so that the extension line of the indicator rod 3 passes through the center of the rotor 1. An arm 14 is attached to the other end of the indicator rod 3 substantially perpendicularly to the indicator rod 3, and a cylindrical rod-like slider is attached to the end of the arm 14 so that the extension line of the slider 15 passes through the center of the rotor 1. 15 is attached. The slider 15 may be rotatable or fixed with respect to the arm 14, but the indicator rod 3 and the arm 14, and the indicator rod 3 and the rotor 1 are fixed and rotate integrally. The arm 14 is bent along an arc having the same center as that of the rotor 1. A connection end 8 connected to an external device such as a robot arm is attached to the opposite side of the indicator rod 3 around the rotor 1 so as to be symmetrical, for example. The rotor 1 and the connection end 8 are fixed, and as one of them rotates, the other also rotates together.

  The base 2 is provided with two shaft members 4A centered on the rotation axis A and two shaft members 4B (4B not shown but used for convenience of description) centered on the rotation axis B. Yes. The rotation axes A and B pass through substantially the center of the side surface of the base 2 and are orthogonal to each other. Bearings 5a and 5b are rotatably fitted to the shaft member 4A, and first guide rails 11 are attached to the bearings 5a and 5b by screws 6a and 6b (6b not shown), respectively. Bearings 5c and 5d are rotatably fitted to the shaft member 4B, and second guide rails 12 are attached to the bearings 5c and 5d by screws 6c and 6d, respectively. Further, bearings 5e and 5f are rotatably fitted to the shaft member 4B outside the bearings 5c and 5d. The third guide rails 13 are attached to the bearings 5e and 5f by screws 6e and 6f, respectively. Yes. Washers are interposed between the bearings 5a to 5f and the base 2 and between the bearings 5a to 5f and the bearings 5a to 5f.

  The bearing 5b is connected to a connection end 21 for connecting to an external device such as an actuator via a drive shaft 21a. By rotating the connection end 21, the bearing 5b and the first guide rail 11 rotate integrally. On the contrary, when the first guide rail 11 is rotated, the connection end 21 is rotated integrally. The bearing 5c is coupled to a connection end 22 for connecting to an external device such as an actuator via a drive shaft 22a and a bearing 5e. By rotating the connection end 22, the bearing 5c and the second guide rail 12 are integrated. When the second guide rail 12 is rotated, the connection end 22 rotates integrally. The bearing 5f is connected to a connection end 23 for connecting to an external device such as an actuator via a drive shaft 23a. By rotating the connection end 23, the bearing 5f and the third guide rail 13 rotate integrally. On the contrary, when the third guide rail 13 is rotated, the connection end 23 is rotated integrally.

  The shape of the first to third guide rails 11, 12, 13 will be described in detail. First, the first guide rail 11 is curved in an arc shape having the same center as the rotor 1, and is connected to the bearings 5 a, 5 b at both ends. The connection part 11b for doing is provided. The second and third guide rails 12 and 13 are each formed with two vertical portions 12b and 13b so that both ends of the second and third guide rails 12 and 13 rise perpendicularly to the rotation axes A and B, respectively. The second and third guide rails 12 and 13 are also curved in an arc shape having the same center as that of the rotor 1 except for these vertical portions. The first guide rail 11 is screwed to the bearings 5a and 5b at the connecting portions 11b at both ends, and the second and third guide rails 12 and 13 are respectively connected to the bearings 5c and 5c at the vertical portions 12b and 13b, respectively. Screwed to 5d and 5e, 5f. Further, a guide rail stopper mechanism 7 is formed on the vertical portions 12b and 13b, which will be described in detail later. Slits 11a, 12a, and 13a are formed in these curved portions of the first to third guide rails 11 to 13, respectively. The indicator rod 3 is slidably inserted into the slits 11a and 12a, and the slider 15 is slidably inserted into the slit 13a.

  Hereinafter, the operation of the three-degree-of-freedom rotation system 100 will be described. The operation based on the interaction between the rotor 1 and the indicator rod 3 and each guide rail is such that guide rails other than the guide rail that interacts with the indicator rod are stationary at a position perpendicular to the plane including the rotation axis A and the rotation axis B. Can be divided into the following three categories. The restriction by the guide rail stopper mechanism 7 will be described later.

  When the first guide rail 11 rotates about the rotation axis A, the first guide rail 11 pushes the indicator rod 3, so that the rotor 1 is centered on the rotation axis A by the same rotation angle as the first guide rail 11. Rotate to. On the other hand, when the rotor 1 rotates around the rotation axis A, the indicator rod 3 is inserted into the slit 11a, so that when the indicator rod 3 pushes the first guide rail 11, the first guide rail 11 is also The rotation axis A rotates about the same rotation angle as the rotor 1. While rotating in this way, the pointer 3 slides through the slit 12a, and the slider 15 slides through the slit 13a. Therefore, the rotor 1 and the indicator rod 3 can rotate until either the indicator rod 3 or the slider 15 reaches the end of the slit 12a or the slit 13a.

  When the second guide rail 12 and the third guide rail 13 are rotated about the rotation axis B in the same direction and at the same rotation angle, the second guide rail 12 pushes the indicator rod 3 so that the rotor 1 is also The third guide rails 12 and 13 rotate about the rotation axis B by the same rotation angle. On the other hand, when the rotor 1 rotates about the rotation axis B, the indicator rod 3 is inserted into the slit 12a, so that when the indicator rod 3 pushes the second guide rail 12, the second guide rail 12, The three guide rails 13 also rotate about the rotation axis B by the same rotation angle as the rotor 1. While rotating in this way, the pointer 3 slides through the slit 11a. Accordingly, the rotor 1 and the indicator rod 3 can rotate until the indicator rod 3 reaches the end of the slit 11a.

  When the third guide rail 13 rotates about the rotation axis B, the third guide rail 13 pushes the slider 15, so that the rotor 1 also rotates the rotation axis by an angle θ corresponding to the rotation angle of the third guide rail 13. Rotate around B. On the contrary, when the rotor 1 rotates around the rotation axis C, the slider 15 also rotates around the rotation axis C. Since the slider 15 is inserted into the slit 13a, when the slider 15 slides in the slit 13a and pushes the third guide rail 13, the third guide rail 13 also has an angle corresponding to the rotation angle θ of the rotor 1. Rotate around the rotation axis B. In other words, when the third guide rail 13 rotates independently of the second guide rail 12, the distance between these guide rails increases or decreases. Therefore, when the distance between the guide rails is increased due to the rigidity of the slider 15, the indicator rod 3 is moved in such a direction that the angle θ (see FIG. 2) formed by the arm 14 and the guide rails approaches 90 degrees. And the rotor 1 rotates. On the other hand, when the interval between these guide rails becomes narrow, the indicator rod 3 and the rotor 1 rotate in a direction in which the angle θ formed by the arm 14 and these guide rails approaches 0 degrees. Conversely, when the rotor 1 rotates with respect to the rotation axis C, the distance between the guide rails increases or decreases depending on the rotation direction, and the angle formed by these guide rails, that is, the difference between the rotation angles is also increased. It gets bigger and smaller.

  Actually, when the indicator rod 3, the rotor 1, the first to third guide rails 11, 12, 13 and the like rotate, all the guide rails stand still perpendicular to the plane including the rotation axis A and the rotation axis B. Since the above three basic operations are combined, the rotor 1, the indicator rod 3 connected to the rotor 1, and the connection end 8 are slits 11a with the center of the rotor 1 as a center point. It can be rotated in any direction within a range limited by the lengths of 12a and 13a.

  Since the first to third guide rails 11, 12, 13, the indicator rod 3, the rotor 1, and the connection end 8 operate in the above relationship, they are connected directly to an external actuator or the like via a gear or the like. By rotating the connection ends 21, 22, and 23, the first, second, and third guide rails integrally connected thereto are rotated integrally with the respective connection ends, whereby the rotor 1 and the rotor are rotated. The indicator rod 3 and the connecting end 8 fixed to 1 can be rotated in any direction within a range limited by the lengths of the slits 11a, 12a, and 13a with the center of the rotor 1 as the center point. .

  For this reason, it is not necessary to move an actuator etc. with a rotating shaft, and since it can fix to the base 2 or a housing | casing etc., a lightweight and small system is realizable.

  Conversely, when an external force is applied to the connection end 8, the connection end 8, the rotor 1, and the indicator rod 3 rotate in the direction in which the external force is most easily received until it is limited by the lengths of the slits 11 a, 12 a, and 13 a. Rotate the guide rail. For this reason, the rotation angle of the indicator rod 3 or the like can be detected by connecting an encoder or the like to the connection ends 21, 22 and 23 directly or via a gear or the like. Again, the encoder or the like can be fixed to the base 2 or the casing, and it is not necessary to move the encoder or the like together with the rotating shaft, so that a lightweight and compact system can be realized.

  Incidentally, as shown in FIG. 4, in the three-degree-of-freedom rotation system 200 mentioned in the prior art, when the distance between the second guide rail 212 and the third guide rail 213 is increased, the distance becomes maximum. (When the difference in rotation angle is maximized), the angle θ between the arm 214 and the second guide rail 212 or the third guide rail 213 becomes 90 degrees. This point is called a singular point. At the singular point, the force from the second guide rail 212 and the force from the third guide rail 213 are just balanced with respect to the arm 214, and no component force is generated to rotate the arm 214. It becomes impossible to rotate. In other words, the singular point is a point at which rotation control about the center of the indicating rod by the second guide rail 212 and the third guide rail 213 becomes impossible. Regarding the conventional three-degree-of-freedom rotation system shown in FIG.

  For this reason, the embodiment of the present invention includes a guide rail stopper mechanism 7 as shown in FIG. 3 in order to avoid the singularity described above. The guide rail stopper mechanism 7 includes, for example, a male stopper 71 which is a cylindrical rod-shaped convex portion formed integrally with one of the vertical portions 12b on the side of the second guide rail 12 facing the third guide rail 13; On the side of the three guide rails 13 facing the second guide rail 12, a female stopper 72 is formed integrally with one of the vertical portions 13b. The female stopper 72 has a pair of substantially rectangular parallelepiped stoppers 72a formed in the vertical portion 13b at predetermined intervals in the width direction of the third guide rail 13 and having the same longitudinal direction as the third guide rail 13. 72b and a recess 72c which is a space between the stoppers 72a and 72b.

The second guide rail 12 and the third guide rail 13 shown in FIG. 3 are assembled as shown in FIGS. 1 and 2 by fitting the shaft holes 42 and 43 to the shaft member 4A in a rotatable manner. The male stopper 71 formed on the rail 12 is accommodated in the recess 72 c between the pair of stoppers 72 a and 72 b of the female stopper 72 formed on the third guide rail 13. When the second guide rail 12 and the third guide rail 13 are rotated independently in this assembled state, the male stopper 71 slides along the locus indicated by T in the recess 72c, and the stoppers 72a on both sides 72b (see FIG. 3). Thereby, the difference between the rotation angles of the second guide rail 12 and the third guide rail 13 can be limited to a predetermined range, and the interval between the second guide rail 12 and the third guide rail 13 can be limited to a predetermined range. The maximum angle θ _MAX between the arm 14 and the second guide rail 12 can be limited so as not to reach 90 degrees, and a singular point can be avoided.

In the present embodiment, the male stopper and the female stopper are formed integrally with the guide rail, but are not necessarily formed integrally, and may be attached to the guide rail by screws or the like. However, by forming them integrally, the stopper is hardly damaged even if a large force is applied to the guide rail. In the present embodiment, the male stopper 71 is provided on the second guide rail 12 and the female stopper 72 is provided on the third guide rail 13. In this embodiment, the guide rail stopper mechanism 7 is provided only at one end of the guide rails 12 and 13, but may be provided at both ends. The shapes of the male stopper 71 and the female stopper 72 are not particularly limited as long as the rotation range of the male stopper 71 can be limited by the female stopper 72. Further, practically, but if the maximum angle theta _MAX is indicated by range of about 60 degrees on each side of the second guide rail 12 as the reference rod 3 may be rotated frequently, the maximum angle theta _MAX than 90 degrees If it is small, there is no particular limitation, and a desired angle may be appropriately selected according to the application. In accordance with this, the interval between the stoppers 72a and 72b of the female stopper 72 may be appropriately selected.

  By providing such a guide rail stopper mechanism 7, it is not necessary to constantly monitor the rotation angles of the second guide rail 12 and the third guide rail 13 in order to avoid singularities, and it is not necessary to use an actuator. Therefore, the structure becomes simple, and a more compact, lightweight and inexpensive system can be realized.

  Furthermore, there are the following advantages compared to the conventional case where the actuator is limited. The first advantage is that the force applied to the guide rails 12 and 13 is stopped by the stoppers 71 and 72 provided on the guide rails 12 and 13 rather than stopping at the position of the shaft member 4B by an actuator or the like. However, the radius from the center of the shaft to the point at which the rotation is stopped (in this embodiment, equal to the distance from the center of the shaft hole 42 to the center of the male stopper 71) as shown in FIG. The lever principle can be stopped with a small force. Even when a large external force is applied to the guide rails 12 and 13, the singular points can be physically avoided by the stoppers 71 and 72 regardless of the torque of the actuator, so that the singular points can be reliably avoided. Compared to the case where the guide rails 12 and 13 are stopped by the shaft members, the stoppers 71 and 72 provided on the guide rails 12 and 13 can be stopped near the point where the force is applied.

  Secondly, when the stoppers 71 and 72 are provided on the guide rails 12 and 13, the structure becomes simple as shown in FIG. Third, the rotation angle error is less likely to occur when the shaft member 4B is stopped at the radius D than when it is stopped at the position of the shaft member 4B (the radius is close to zero), and a system capable of highly accurate positioning can be easily machined. Is a point.

  The guide rail stopper mechanism 7 is arranged in the order of bearings 5f, 5d, 5e, and 5c from the left when the second guide rail 12 and the third guide rail 13 are alternately attached to the rotating shaft, that is, for example, in FIG. As shown in the present embodiment, the third guide rail 13 is disposed outside the second guide rail 12, and the second guide rail 12 and the second guide rail 12 are connected to each other. The three guide rails 13 are preferably nested. Because the guide rails 12 and 13 are nested, the guide rails 12 and 13 are provided with stoppers 71 and 72 without any special shape or additional parts. This is because the area where the two guide rails 12 and the third guide rail 13 overlap increases, so that the radius D for stopping the rotation can be increased, and the range of selection of the recess width is widened.

  In the present embodiment, the above-described three-degree-of-freedom rotation system 100 in which the indicator rod 3 and the rotor 1 are rotated by the three guide rails 11 to 13 having slits is exemplarily shown. The stopper mechanism is not limited to this, and can be applied to any three-degree-of-freedom rotation system that generates a singular point. For example, instead of providing the guide rails 11 to 13 with the slits 11a to 13a, the slider may be formed in a pipe shape so that the slider slides on the guide rail. In addition, for example, the indicator rod 3 may be positioned in the middle of the arm, and the two sliders may slide along the second and third guide rails, respectively. The vertical portions 12b and 13b may be curved portions. An example of a three-degree-of-freedom rotation system to which the present invention can be applied is described in detail in the patent document “International Publication WO / 2004/011824”.

  As mentioned above, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken. Modifications and the like can be made without departing from the technical idea of the present invention, and such modifications and equivalents are also included in the technical scope of the present invention.

  The guide rail stopper mechanism of the present invention and the three-degree-of-freedom rotation system including the mechanism can be used in various applications. A multi-degree-of-freedom robot arm with a small moment of inertia can be created while overcoming the problem of point. Further, when an external force is applied to the robot arm, the tip of the robot arm can be moved in the direction in which the external force is most easily received until the slider is limited by the stopper. Furthermore, even when the stopper becomes effective, it can continue to receive external force around the remaining rotating shaft. The present invention is applicable as a hand effector for various robots. The present invention is expected to realize a small and lightweight three-degree-of-freedom robot joint that is safe even if it comes into contact with the human body, and promotes the development of various robots.

It is the perspective view which drawn three-dimensionally the 3 degrees of freedom rotation system provided with the guide rail stopper mechanism of the embodiment of the present invention. It is the perspective view which drawn the same 3 degree-of-freedom rotation system from another angle. It is the perspective view which drawn the guide rail stopper mechanism of this embodiment three-dimensionally. It is the top view which drew three-dimensionally the state where the conventional 3 degree-of-freedom rotation system reached the singular point.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... 3 degree-of-freedom rotation system 1 ... Rotor 2 ... Base 3 ... Indicating bar 4A, 4B ... Shaft member 5a, 5b, 5c, 5d, 5e, 5f ... Bearing 6a 6b, 6c, 6d, 6e, 6f ... Screw 7 ... Guide rail stopper mechanism 71 ... Male stopper 72 ... Female stopper
72a, 72b ... stopper 72c ... recess 8 ... connection end 11 ... first guide rail 11a ... slit 11b ... connection 12 ... second guide rail 12a ... slit 12b ... Vertical part 13 ... Third guide rail 13a ... Slit 13b ... Vertical part 14 ... Arm 15 ... Slider 21, 22, 23 ... Connection end 21a, 22a, 23a ... Drive shaft 42, 43 ... Shaft hole θ ... An angle formed by arm 14 and second guide rail 12 D ... Radius T ... Trace 200 ... Conventional 3-DOF rotation system 201 ... Rotor 202 ... Base 211 ... First guide rail 212 ... Second guide rail 213 ... Third guide rail 211a, 212a, 213a ... Slit 214 ... Arm 215. ..Slider

Claims (5)

A rotor including a part or all of a sphere, an indicator rod, an arm, at least one slider, at least one base, four shaft members, six bearings, first to third Including three guide rails,
The rotor is provided with the indicator rod,
At least one of the sliders is attached to or connected to the indicator bar via the arm,
Using the two shaft members and the two bearings, the first guide rail is attached to the base,
The second guide rail and the third guide rail are attached to the base using the remaining two shaft members and the remaining four bearings,
The first guide rail is slidably connected to the indicator bar,
The third guide rail is slidably connected to the slider,
The second guide rail is slidably connected to the indicator rod or the second slider,
By rotating the first guide rail, the second guide rail, and the third guide rail, the rotor and the indicator rod rotate in three directions with the center of the rotor as a center point. In the system,
A female stopper with a recess is provided on either the second guide rail or the third guide rail,
A male stopper with a convex part is provided on the other guide rail,
While the convex portion slides in the concave portion and the convex portion hits one end of the concave portion, the sliding of the convex portion is limited,
Thus, the difference in rotational angle between the second guide rail and the third guide rail is limited, and the angle formed by the second guide rail and the arm is limited. mechanism.   The stopper mechanism according to claim 1, wherein the female stopper and / or the male stopper are formed integrally with the second and / or third guide rail.   A three-degree-of-freedom rotation system comprising the guide rail stopper mechanism according to claim 1.   The three-degree-of-freedom rotation system according to claim 3, wherein the second guide rail and the third guide rail are attached to the shaft member supporting the second guide rail and the third guide rail in a nested manner.   A three-degree-of-freedom robot joint comprising the three-degree-of-freedom rotation system according to claim 3.