JP5833869B2 - Delta parallel robot - Google Patents

Description

  The present invention relates to a delta parallel robot including a base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base.

  The delta type parallel robot includes a base, a bracket for attaching a tool, and three sets of arm mechanisms that connect the bracket to the base. In general, the arm mechanism includes an upper link, a pair of links, and a lower link that constitute a parallel link, and the base is disposed horizontally. The arm mechanism operates so that the upper link and the lower link maintain a horizontal posture. Thereby, the bracket and the tool can move while maintaining a horizontal posture without changing the posture with respect to the base. Utilizing this characteristic, delta type parallel robots are widely used for picking work in food factories and the like. If it becomes possible to change the posture of the bracket and the tool with respect to the base as needed, the workability and applicability of the delta type parallel robot are expanded and beneficial.

  Patent Document 1 discloses a delta type parallel robot having a bracket capable of controlling 6 degrees of freedom. This delta type parallel robot has three sets of arm mechanisms, and each arm mechanism has two links and a rod. Each link base end is swingably connected to the base, each link tip is connected to a corresponding rod base end via a ball pair, and each rod tip is connected to a bracket via a ball pair. A total of six drive motors for individually driving the links are provided on the base. In the actual structure of the robot disclosed in Patent Document 1, there is a lower link that connects the ball pairs at the tip of the rod, but there is no upper link that connects the balls of the rod base end (link tip). Hereinafter, for convenience of explanation, a line connecting the ball pairs at the rod base end (link tip) is referred to as “virtual upper link”.

  If the two drive motors corresponding to each arm mechanism operate at the same angle, the posture of the arm mechanism with respect to the base of the virtual upper link does not change, and the bracket and the tool can be moved without changing the posture with respect to the base. . If the two drive motors operate at different angles, the attitude of the virtual upper link with respect to the base changes, the virtual upper link becomes non-horizontal, and the attitude of the tool and bracket with respect to the base changes.

JP-A-6-270077

  In the parallel robot of Patent Document 1, the distance from the swing fulcrum of the link base end to the rotation center of the link front end (that is, the rod base end) is long. For this reason, when it is going to change the attitude | position of a bracket, the required torque for rocking | fluctuating a link becomes large. Further, the rate of change of the tilt angle of the virtual upper link with respect to the swing angle of the link increases. Therefore, it becomes difficult to accurately control the posture of the bracket. In order to control the posture in such a parallel robot, it is necessary to provide a reducer with a large deceleration rate.

  Further, the inclination angle of the virtual upper link and the inclination angle of the lower link are in a non-linear relationship, and the inclination angle of the lower link increases exponentially as the swing angle of the link increases. For this reason, as the posture change amount with respect to the bracket and the base of the tool increases, it becomes difficult to accurately control the posture. In order to control the posture in such a parallel robot, a complicated model that represents the nonlinear relationship is created in advance, and linearization processing must be performed by a complicated calculation using the model in the controller. Don't be.

  Therefore, an object of the present invention is to provide a delta parallel robot that can easily and accurately control the posture of a bracket.

  A delta type parallel robot according to the present invention includes a base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base, and each arm mechanism has a base end portion that is the base end portion. One arm pivotably connected to the base, a pair of links arranged so as to sandwich the base end of the arm and the bracket, and the pair of links to the base end of the arm. A pair of proximal joints that are pivotably coupled, and a pair of distal joints that pivotally couple the pair of links to the bracket, respectively, the pair of links, the pair of proximal joints, and The pair of tip joints are arranged so as to form a parallel link, and at least one of the three sets of arm mechanisms includes at least the arm of the arm. End is configured to be rotatable about the axis of the arm.

  According to the above-described configuration, when the arm rotates around the axis (hereinafter simply referred to as “rotation”), the pair of proximal joints corresponding to the arm are rotated along the axis of rotation of the arm (that is, the axis of the arm). Revolve around. Then, the arm mechanism is deformed, and the posture of the bracket with respect to the base can be changed. At this time, the proximal joint rotates with the distance from the rotation axis of the arm as a radius. Therefore, the radius of rotation of the proximal joint can be reduced, and the amount of change in the posture of the bracket with respect to the rotation angle of the arm is reduced. Then, the required torque for rotating the arm is small, and the posture of the bracket can be controlled with high accuracy. Further, when the arm rotates, the apparent distance between the pair of proximal joints does not change, so that the inclination angle of the proximal joint and the inclination angle of the distal joint become substantially equal. Then, the rotation angle of the arm and the inclination angle of the tip joint satisfy a substantially linear relationship. Accordingly, the posture of the bracket can be accurately controlled without performing complicated calculations.

  A plurality of arm mechanisms of the three sets of arm mechanisms may be configured such that at least the tip portion of the arm can rotate about the axis of the arm. According to the said structure, the attitude | position of a bracket can be changed intricately. As an example, the bracket can be moved on a plane perpendicular to a straight line connecting a pair of tip joints corresponding to arms that do not rotate.

  All of the three sets of arm mechanisms may be configured such that at least the tip portion of the arm can rotate about the axis of the arm. According to the said structure, the attitude | position of a bracket can be changed intricately. As an example, the bracket can be rotated.

  A rotation actuator that rotates the arm around the axis of the arm may be further provided, and the rotation actuator may be attached to the base. According to the above configuration, since the rotation actuator is attached to the base, it is possible to avoid a load from acting on the rotation actuator when the arm swings.

  A rotation actuator that rotates the arm around the axis of the arm may be further provided, and the rotation actuator may be attached to the arm. According to the above configuration, since the rotation actuator is attached to the arm, the mechanism for transmitting the power of the rotation actuator can be omitted or downsized.

  ADVANTAGE OF THE INVENTION According to this invention, the delta type | mold parallel robot which can control the attitude | position of a bracket easily and accurately can be provided.

It is a side view of the delta type parallel robot concerning a 1st embodiment of the present invention. It is a schematic diagram which shows the structure and operation | movement of an arm mechanism shown in FIG. 2A shows a state in which the rotation angles of the three arms are all at the reference rotation angle, and FIG. 2B shows a state in which the rotation angle of the arm is displaced from the reference rotation angle. It is a block diagram which shows the structure of the delta type | mold parallel robot shown in FIG. It is a schematic diagram which shows the aspect of the attitude | position change of a bracket when operating the autorotation actuator shown in FIG. FIG. 4A illustrates a case where one arm is rotated independently from when all the upper and lower links of the three sets of arm mechanisms are in the standard posture. FIG. 4B illustrates a case where the two arms are simultaneously rotated from the time when the upper link and the lower link of the three sets of arm mechanisms are all in the standard posture. FIG. 4C illustrates a case where the three arms are simultaneously rotated from the time when all the upper links and lower links of the three arm mechanisms are in the standard posture. FIG. 5A is a schematic diagram geometrically showing a set of arm mechanisms before arm rotation. FIG. 5B is a schematic diagram of the arm mechanism before the arm rotation shown in the extending direction of the rotation axis in the first embodiment. FIG.5 (c) is a schematic diagram of the arm mechanism after the arm rotation shown in the same direction as FIG.5 (b) in 1st Embodiment. FIG.5 (d) is a schematic diagram of the arm mechanism before the link rocking | fluctuation shown in the extension direction of a link in a comparative example. FIG.5 (e) is a schematic diagram of the arm mechanism after the link rocking | fluctuation shown in the same direction as FIG.5 (d) in a comparative example. FIG. 5 (f) is a schematic diagram showing the proximal joint after arm rotation in the first embodiment, and FIG. 5 (g) is a schematic diagram showing the proximal ball pair after rocking the link in the comparative example. It is. It is a graph which shows the relationship between the arm rotation angle in 1st Embodiment, and the inclination angle of a lower link, and the relationship between the link rocking | fluctuation angle in a comparative example, and the inclination angle of a lower link. It is sectional drawing of the arm which shows arrangement | positioning of the rocking | fluctuation actuator shown in FIG. 3, and a rotation actuator. It is a front view which shows a part of arm shown in FIG. It is sectional drawing of the arm which shows arrangement | positioning of the rocking | fluctuation actuator and rotation actuator which concern on 2nd Embodiment of this invention. It is sectional drawing of the arm which shows arrangement | positioning of the rocking | fluctuation actuator and rotation actuator which concern on 3rd Embodiment of this invention. It is sectional drawing of the arm which shows arrangement | positioning of the rocking | fluctuation actuator and rotation actuator which concern on 4th Embodiment of this invention. It is a front view which shows a part of arm concerning 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same or corresponding elements are denoted by the same reference numerals throughout the drawings, and detailed description thereof is omitted. Hereinafter, the delta parallel robot may be simply referred to as “robot”.

[First Embodiment]
FIG. 1 is a side view of the robot 1 according to the first embodiment of the present invention. The robot 1 shown in FIG. 1 can change not only the position of the work tool 9 but also the posture, and has a wider range of applicability than a conventional general robot. For example, the robot 1 is suitably used for various operations such as a picking operation, a boxing operation, and a component assembly operation in a production facility 90 such as food, medicine, cosmetics, or small electrical components.

(overall structure)
As shown in FIG. 1, the robot 1 includes a base 2, a bracket 3, three sets of arm mechanisms 4, and three swing actuators 5. The base 2 is formed in a bucket shape, for example, and is fixed to the gantry 91. The bracket 3 is formed in a substantially flat plate shape, for example, and the work tool 9 is detachably attached to the lower surface of the bracket 3. Each arm mechanism 4 connects the bracket 3 to the base 2.

  Each arm mechanism 4 has one arm 10, a pair of links 11, 12, a pair of proximal joints 13, 14, and a pair of distal joints 15, 16. 12, the pair of proximal joints 13 and 14 and the pair of distal joints 15 and 16 are arranged so as to form parallel links. “Arrangement of parallel links to be configurable” means that the pair of links 11, 12, the pair of proximal joints 13, 14, the pair of distal joints 15, 16, and the pair of proximal joints 13, 14 are connected. A parallel link can be constituted by the upper link 17 and the lower link 18 connecting the pair of tip joints 15 and 16, and of course, depending on the situation, the posture of the upper link 17 and the lower link 18 is intentionally set. It means that it can be changed.

  The base end portion of the arm 10 is connected to the base 2 so as to be swingable. The swing axis 10 a of the arm 10 is disposed within the reference plane RP and is disposed 120-degree rotationally symmetrical with respect to the central axis 2 a of the base 2. The reference plane RP and the central axis 2a do not move regardless of the operation of the robot 1, and the reference plane RP is orthogonal to the central axis 2a. For example, the central axis 2a is oriented vertically and the reference plane RP is arranged horizontally. The three oscillating actuators 5 individually correspond to a total of three arms 10. When any of the swing actuators 5 is operated, the corresponding arm 10 swings around the swing axis 10a.

  The pair of links 11 and 12 are arranged so as to sandwich the tip of the arm 10 and the bracket 3. The pair of proximal joints 13 and 14 connect the proximal ends of the links 11 and 12 to the distal ends of the arms 10 so as to be rotatable. The tip joints 15 and 16 respectively connect the tip portions of the links 11 and 12 to the bracket 3 so as to be rotatable. The proximal joints 13 and 14 and the distal joints 15 and 16 constitute a ball pair.

(Configuration and operation of arm mechanism)
FIG. 2 is a schematic diagram showing the configuration and operation of the arm mechanism 4. As shown in FIG. 2A, the arm 10 includes a cylindrical arm main body 45 and a tip arm 47 provided at the tip of the arm main body 45. The pair of proximal joints 13 and 14 is composed of a pair of balls 23 and 24 provided at both ends of the distal arm 47 and a pair of sockets 25 and 26 fitted to the balls 23 and 24, respectively. The pair of sockets 25 and 26 are fixed to the base ends of the two links 11 and 12, respectively. The distal arm 47 serves as an upper link 17 that couples the pair of proximal joints 11 and 12 to each other.

  A flange 30 is provided at the edge of the bracket 3, and a pair of lower protrusions 31 and 32 protruding from the flange 30 to the opposite sides are provided. The pair of tip joints 15, 16 is composed of a pair of balls 33, 34 provided at the tips of the lower protrusions 31, 32, and a pair of sockets 35, 36 that fit into the balls 33, 34, respectively. Yes. The pair of sockets 35 and 36 are fixed to the tip ends of the two links 11 and 12, respectively. The pair of lower protrusions 31 and 32 and the flange 30 interposed therebetween serve as a lower link 18 that connects the pair of tip joints 15 and 16 to each other. The pair of links 11 and 12 have the same length, and the upper link 17 has the same length as the lower link 18.

  As shown by the arc-shaped arrow in FIG. 2B, the arm 10 can rotate around the axis 10b. The axis 10 b extends from the proximal end portion of the arm 10 toward the distal end portion, is orthogonal to the upper link 17, and passes through the midpoint of the upper link 17. In the following, such rotation of the arm 10 is referred to as “rotation”, the axis 10b that is the center of rotation is referred to as “rotation axis”, and the angular position of the arm 10 around the rotation axis 10b is referred to as “rotation angle”. Called.

  As shown in FIG. 2A, when the rotation angle of the arm 10 is at a certain reference rotation angle, the pair of links 11 and 12 are parallel to each other. Also, the pair of proximal joints 13 and 14 and the pair of distal joints 15 and 16 are disposed on the planes RP1 and RP2 parallel to the reference plane RP, and the upper link 17 and the lower link 18 are disposed on the planes RP1 and RP2. The upper link 17 is parallel to the lower link 18. Therefore, the pair of links 11 and 12, the pair of proximal joints 13 and 14, the pair of distal joints 15 and 16, the upper link 17 and the lower link 18 constitute a parallel link, and the bracket 3 is also parallel to the reference plane RP. It arrange | positions on plane RP3 (refer FIG. 1). Therefore, when the arm 10 swings while the rotation angle remains the reference rotation angle, the bracket 3 and the work tool 9 can move in the three-axis directions without changing the posture with respect to the base 2. Hereinafter, the posture when the upper link 17 is disposed on the plane RP1 parallel to the reference plane RP is referred to as a “standard posture” for convenience. The same applies to the lower link 18.

  As shown in FIG. 2B, when the arm 10 is displaced from the reference rotation angle, the posture of the upper link 17 is inclined from the standard posture, and the pair of proximal joints 13 and 14 revolve around the rotation shaft 10b. . Thereby, the posture of the lower link 18 is also inclined from the standard posture. As the lower link 18 is inclined, the posture of the bracket 3 with respect to the base 2 also changes. Hereinafter, the inclination angle of the upper link 17 with respect to the standard posture is referred to as “upper link inclination angle”, and the inclination angle of the lower link 18 with respect to the standard posture is referred to as “lower link inclination angle”. As described above, in the present embodiment, the arm mechanism 4 includes one arm 10, and the arm 10 can rotate, and the posture of the upper link 17 can be changed as the arm 10 rotates. When the postures of the upper link 17 and the lower link 18 are changed in this way, the pair of links 11, 12, the upper link 17 and the lower link 18 are twisted and are not arranged on the same plane. Since the influence on the posture change of the tool 9 is small, the influence of the twist is ignored in the description of the embodiment. For this reason, the posture of the bracket 3 can be changed together with the posture of the lower link 18, thereby expanding the applicability of the robot 1.

(Control system)
FIG. 3 is a block diagram showing a configuration of the robot 1 shown in FIG. As shown in FIG. 3, the robot 1 includes three rotation actuators 50, and the three automatic actuators 50 individually correspond to the three arms 10. The rotation angle of the arm 10 changes according to the operation of the rotation actuator 50. That is, it is possible to intentionally change the postures of the upper link 17 and the lower link 18 by controlling the rotation actuator 50, thereby changing the postures of the bracket 3 and the work tool 9 attached thereto. It becomes.

  The robot 1 includes a controller 70 that controls the three swing actuators 5 and the three rotation actuators 50. The controller 70 controls the operations of the actuators 5 and 50 according to the control program stored in the storage unit, thereby controlling the position and posture of the bracket 3 and the work tool 9 attached thereto.

(Mode of operation)
FIG. 4 is a schematic diagram showing a manner of posture change of the bracket 3 when the rotation actuator 50 is operated. In FIG. 4, the lower surface of the bracket 3 is directed upward in the drawing, contrary to FIG. 1.

<Aspect 1: Single independent rotation of one arm>
FIG. 4A illustrates a case where one arm 10 is rotated independently from when the upper link 17 and the lower link 18 of the three sets of arm mechanisms 4 are all in the standard posture. In such a case, the posture of the bracket 3 changes so that the midpoint M of the lower link 18 corresponding to the arm 10 draws an arc or an elliptical arc. More specifically, the trajectory of the midpoint M is the apex at the point Q near the intersection P between the extension lines of the two lower links 18 corresponding to the two arms 10 that do not rotate. , And moves along the bottom circumference of a cone or elliptical cone with the straight line connecting the point Q to the midpoint M as the generating line L.

<Aspect 2: Rotation of two arms>
FIG. 4B shows a case where the two arms 10 are rotated at the same time from when the upper link 17 and the lower link 18 of the three sets of arm mechanisms 4 are all in the standard posture. The case where 10 rotates in the opposite direction mutually at the same speed is illustrated. In such a case, the bracket 3 moves on a plane perpendicular to the lower link 18 corresponding to the arm 10 that does not rotate. For example, the posture of the bracket 3 is changed such that the intersection point P between the extension lines of the two lower links 18 corresponding to the two rotating arms 10 moves substantially upward or substantially downward on the plane.

<Aspect 3: Rotation of three arms>
FIG. 4 (c) shows a case where the three arms 10 are rotated in the same direction from the time when the upper arm 17 and the lower link 18 of the three sets of arm mechanisms 4 are all in the standard posture. In the example shown in FIG. In such a case, the bracket 3 rotates around an axis A (axis parallel to the center axis 2a of the base 2 (see FIG. 1)) perpendicular to the reference plane RP.

  As described above, by appropriately selecting which arm 10 of the three arms 10 is to be rotated and how to set the rotation speed and the rotation direction of the arm 10 to be rotated, the bracket 3 and The posture of the work tool 9 to be attached can be variously changed.

  In order to realize all the movements shown in FIGS. 4A to 4C, it is necessary that all the arms 10 can rotate and the robot 1 includes the three rotation actuators 50. However, if the purpose is to realize the movement shown in FIGS. 4 (a) and 4 (b), it is sufficient that at least two arms 10 are configured to be rotatable, as shown in FIG. 4 (a). If the purpose is to realize movement, it is sufficient that at least one arm 10 is configured to be capable of rotating. In such a case, the number of the rotation actuators 50 can be appropriately reduced.

  In addition, regarding the operation | movement aspect shown in FIG.4 (c), the autorotation movable range of the bracket 3 by autorotation of the arm 10 does not become a large thing, for example, +/- 360 degree | times. For this reason, when the tool 9 needs to be largely rotated for the purpose of the robot 1, an actuator 79 (see FIG. 1) for rotating the tool 9 may be provided exclusively. Conversely, if it is sufficient if the tool 9 can be rotated a little, the tool 9 can be rotated after omitting the actuator dedicated to the tool, and as shown in FIGS. 4 (a) and 4 (b). It is very beneficial because it also makes it possible to change posture.

(Comparison between this embodiment and conventional example)
Here, referring to FIGS. 5 and 6, the relationship between the rotation angle of the arm 10 and the inclination angle of the upper link 17, the relationship between the rotation angle of the arm 10 and the inclination angle of the lower link 18, The relationship between the inclination angle of the link 17 and the inclination angle of the lower link 18 will be described in comparison with a conventional delta type parallel robot. In addition, through this comparison, the effect of the robot 1 according to the present embodiment that the posture of the bracket 3 can be easily and accurately controlled will be described in detail. The comparative example here is a robot as disclosed in Patent Document 1.

  As described above, in this embodiment, the arm mechanism 4 includes one arm 10 and two links 11 and 12, and the pair of proximal joints 13 and 14 are mechanically connected via the upper link 17. The pair of tip joints 15 and 16 are mechanically connected via the lower link 18. On the other hand, in the comparative example, the arm mechanism includes two links and two rods, the base ends of the links are connected to the base via cylindrical pairs, and the tips of the links are connected to the bases via ball pairs. Connected to the base end, the tip of each rod is connected to the bracket via a ball pair. Although it can be said that the two ball pairs on the rod front end side are mechanically connected to each other, the two ball pairs on the rod proximal end side are not mechanically connected to each other. In consideration of the difference in the configuration of the arm mechanism, in the comparative example, a straight line connecting the two ball pairs on the rod base end side is “virtual upper link”, and a straight line connecting the two ball pairs on the rod tip side is connected. This will be described as “downlink”. By assuming such a virtual upper link, the behavior of the upper link 17 according to the present embodiment can be satisfactorily compared with the robot according to the comparative example.

  As described above, in this embodiment, in order to realize the posture change of the bracket 3, one rotation actuator 50 is provided for the arm mechanism 4 having an arm capable of rotation. On the other hand, in the comparative example, two motors are provided for one set of arm mechanisms. Considering the difference in the configuration of the drive system, in the comparative example, it is assumed that the two motors rotate to the opposite sides at the same speed. Under these conditions, the tips of the two links according to the comparative example move to opposite sides at the same speed, and the behavior of the upper link 17 according to the present embodiment is the same as the behavior of the virtual upper link according to the comparative example. A good comparison can be made.

  Hereinafter, how the inclination angle of the upper link 17 and the inclination angle of the lower link 18 change with the rotation of the arm 10 of the pair of arm mechanisms 4 will be described. The posture of the arm mechanism 4 before the arm rotation in this embodiment is the same as that of the comparative example. Here, as shown in FIG. 5A, before the arm rotates, the three arm mechanisms 4 are all in the standard posture, and in the one arm mechanism 4, the arm 10 is connected to the links 11 and 12. It shall be a right angle.

  FIG. 5 (a) shows a geometrical view of the set of arm mechanisms 4 before arm rotation, projected onto a two-dimensional plane so that the pair of links 11, 12, the upper link 17 and the lower link 18 overlap. It is the shown schematic diagram. The arm mechanism 904 of the comparative example corresponds to the arm mechanism 4 according to the present embodiment, the link 910 of the comparative example corresponds to the arm 10 according to the present embodiment, and the rods 911 and 912 according to the comparative example correspond to the present embodiment. The base end side ball pair 913, 914 according to the comparative example corresponds to the link 11, 12 according to the comparative example, the base end joint pair 13, 14 according to the present embodiment, and the front end ball pair 915, 916 according to the comparative example is The virtual upper link 917 according to the comparative example corresponds to the distal joints 15 and 16 according to the present embodiment, the virtual upper link 917 according to the comparative example corresponds to the upper link 17 according to the present exemplary embodiment, and the lower link 918 according to the comparative example corresponds to the lower link according to the present exemplary embodiment. It corresponds to the link 18.

  FIG. 5B is a schematic diagram of the arm mechanism 4 before the arm rotation shown in the direction in which the rotation axis 10b extends in the present embodiment. As shown in FIG. 5B, when the arm mechanism 4 is viewed in this direction, the pair of links 11, 12, the upper link 17 and the lower link 18 form a rectangle, and the rotation axis 10 b is in the upper link 17. Shown as dots at points.

  FIG.5 (c) is the schematic diagram of the arm mechanism 4 after the arm rotation shown in the same direction as FIG.5 (b) in this embodiment. When the arm 10 rotates by a certain angle, it can be considered that the upper link 17 and the lower link 18 are rotated and inclined on the spot. Actually, when the upper link 17 is inclined, the lower link 18 moves so as to approach the right or left side of the page. This movement is negligible compared to the inclination of the upper link 17 and the lower link 18. small. Therefore, as described above, the upper link 17 and the lower link 18 are regarded as rotating on the spot. The upper link 17 rotates by the same angle as the arm 10. That is, the inclination angle θ1 of the upper link is equal to the rotation angle from the reference rotation angle of the arm 10.

  In the present embodiment, the pair of proximal joints 13 and 14 are mechanically coupled via the upper link 17, and the pair of distal joints 15 and 16 are mechanically coupled via the lower link 18. For this reason, the distance between the pair of proximal joints 13 and 14 is unchanged regardless of the inclination angle θ 1 of the upper link 17, and the distance between the pair of distal joints 13 and 14 is also the inclination angle of the lower links 15 and 16. Regardless, it is unchanged. For this reason, after arm rotation, although a pair of link 11,12, the upper link 17, and the lower link 18 are not a rectangle, they comprise a parallelogram. Therefore, the inclination angle θ2 of the lower link 18 is equal to the inclination angle θ1 of the upper link 17. It can also be said that the inclination angle θ2 of the lower link 18 has a linear relationship with the inclination angle θ1 of the upper link 17.

  FIG. 5D is a schematic diagram of the arm mechanism 904 before the link swinging as seen in the extending direction of the link 910 in the comparative example. As shown in FIG. 5D, when the arm mechanism 904 is viewed in this direction, the pair of rods 911, 912, the virtual upper link 917, and the lower link 918 form a rectangle as in this embodiment. The pair of links 910 are shown as dots at both ends of the virtual upper link 917.

  FIG. 5E is a schematic diagram of the arm mechanism 904 after the link swinging shown in the same direction as FIG. 5D in the comparative example. As shown in FIG. 5E, also in the comparative example, it can be considered that the virtual upper link 917 and the lower link 918 are rotated and inclined on the spot while ignoring the left-right movement of the lower link 918. However, since the tips of the links 910 are not restrained from each other, when the link 910 swings, the tips of the links 910 apparently move upward or downward in the drawing. Thereby, the apparent length of the virtual upper link 918 increases as the swing angle of the link 910 increases. On the other hand, the length of the pair of rods 911 and 912 and the length of the lower link 918 are unchanged. Accordingly, the pair of rods 911, 912 forms a square shape. That is, the facing distance between the pair of rods 911 and 912 is larger on the virtual upper link 917 side than before the link swing, and is smaller on the lower link 918 side than before the link swing. For this reason, as the inclination angle of the virtual upper link 917 increases, the inclination angle θ92 of the lower link 918 increases exponentially. Thus, in the comparative example, the inclination angle θ92 of the lower link 918 has a non-linear relationship with the inclination angle θ91 of the virtual upper link 917.

  Even if the inclination angle θ91 of the virtual upper link 917 in the comparative example is the same as the inclination angle θ1 of the upper link 17 in the present embodiment, the swing angle of the link 910 in the comparative example is the same as that of the arm 10 in the present embodiment. It is not always the same as the rotation angle. Here, when the length of the upper link 17 (virtual upper link 917) is L1, and the distance from the swing axis of the arm 10 (link 910) to the proximal joint (tip of the link 910) is L2, this implementation In the embodiment, the rotation angle of the arm 10 is substantially equal to the inclination angle θ1 of the upper link 17 regardless of the lengths of the upper link 17 and the arm 10. In the comparative example, when the swing angle of the link 910 is θ90 and the inclination angle of the virtual upper link 917 is θ91, L2 × sin θ90 = 1/2 × L1 × tan θ91 must be satisfied (FIG. 5E). reference).

  As described above, the tangent of the inclination angle θ91 of the virtual upper link 917 has a relationship with the sine of the swing angle θ90 of the link 910. For this reason, the inclination angle θ91 of the virtual upper link 917 shows a complicated change with respect to the change of the swing angle θ90 of the link 910. The rate of change of the inclination angle θ91 of the virtual upper link 917 with respect to the swing angle θ90 of the link 910 depends on the ratio of the length of the virtual upper link 917 to the length of the link 910 (L2 / L1). As the link 910 becomes longer than the virtual upper link 917, the inclination angle θ91 of the virtual upper link 917 changes greatly according to the change in the swing angle of the link 910. In general, the link 910 is longer than the virtual upper link 917, and is about 7 to 11 times. Therefore, in the comparative example, the rate of change of the inclination angle θ91 of the virtual upper link 917 with respect to the swing angle θ90 of the link 910 is 7 of the rate of change of the inclination angle θ1 of the upper link 17 according to this embodiment with respect to the rotation angle of the arm 10. It becomes about 11 times from double.

  FIG. 6 is a graph showing the inclination angle of the lower link with respect to the rotation angle of the arm. A line connecting rectangular plots represents this embodiment, and a line connecting round plots represents a comparative example. In the comparative example, the inclination angle of the virtual upper link 917 greatly changes with respect to the swing angle of the link 910, and the inclination angle of the virtual upper link 917 has a non-linear relationship with the inclination angle of the lower link 918. For this reason, in order to control the attitude of the bracket 3 with high accuracy, the nonlinear relationship must be stored in advance in the controller as a model, and the linearization process must be performed by a complicated calculation using the model. . In the comparative example, if the lower link 918 is inclined by the same angle as the lower link 18 of the present embodiment, the swing angle of the link 910 is set to 1/7 to 1/11 of the rotation angle of the arm 10 of the present embodiment. It must be made as small as possible. For this reason, the control accuracy (resolution) of the posture of the lower link 918 is inferior by this ratio, and the required torque of the motor of the comparative example is larger than that of the rotation actuator 50 according to the present embodiment. If it is desired to improve the control accuracy of the posture of the lower link 918, it is necessary to provide a large speed reducer on the base.

  On the other hand, in this embodiment, the rotation angle of the arm 10 is substantially equal to the inclination angle of the upper link 17, and the inclination angle of the upper link 17 is substantially equal to the inclination angle of the lower link 18. Therefore, the rotation angle of the arm 10 is substantially equal to the inclination angle of the lower link 18, and the rotation angle of the arm 10 has a linear relationship with the inclination angle of the lower link 18. For this reason, when tilting the lower link 18 to change the posture of the bracket 3, the operation command value for the rotation actuator 50 can be easily obtained. Moreover, the rate of change of the inclination angle of the lower link 18 with respect to the rotation angle of the arm 10 is significantly smaller than that of the comparative example. For this reason, the required torque of the rotation actuator 50 may be small, and a reduction gear for reducing the rotational power of the rotation actuator 50 can be miniaturized.

  FIG. 5 (f) is a schematic diagram showing the base joint 14 after arm rotation, and FIG. 5 (g) is a schematic diagram showing the base-side ball pair 914 after rocking the link. As can be seen by comparing FIG. 5 (f) and FIG. 5 (g), in the comparative example, the pair of rods 911, 912 has a square shape. For this reason, it becomes extremely difficult for the base-end-side ball pair 914 to receive a vertical upward force among the upward force FVU, horizontal force FH, and downward force FVL. In the present embodiment, the square shape formed by the pair of links 11, 12, the upper link 17, and the lower link 18 does not change as much as the comparative example between before and after the rotation of the arm 10. For this reason, it can suppress that the area which receives force in the base end joint 14 becomes unbalanced in the up-down direction or the left-right direction. The same applies to the tip joints 15 and 16 and the tip side ball pair 915 and 916. As a result, in this embodiment, the arm mechanism 4 having high rigidity can be provided.

(Arrangement of swing actuator and rotation actuator)
FIG. 7 is a cross-sectional view of the arm 10 showing the arrangement of the swing actuator 5 and the rotation actuator 50 shown in FIG. As shown in FIG. 7, the base 2 has a deceleration box 41. The swing actuator 5 is, for example, an electric motor, and is fixed to the speed reduction box 41 of the base 2, and its output shaft 5 a is disposed in the speed reduction box 41. The deceleration box 41 houses a rocking reduction gear 42 that decelerates the rotational power of the rocking actuator 5 and transmits it to the rocking shaft 43. The swing shaft 43 is rotatably supported by the reduction box 41 and is fixed to the base end portion of the arm 10, and the central axis of the swing shaft 43 forms the swing axis 10a. When the swing actuator 5 operates, the swing shaft 43 is driven to rotate, and the arm 10 swings around the swing axis 10 a together with the swing shaft 43. 3 illustrates the case where a spur gear train is applied to the swinging speed reducer 42, any power transmission mechanism may be applied to the swinging speed reducer 42.

  The arm 10 according to the present embodiment includes the arm body 45 and the distal arm 47 described above, and a housing 46 interposed between the arm body 45 and the distal arm 47. The swing shaft 43 is fixed to the base end portion of the arm main body 45. The container 46 is surrounded by the first wall 46a on the base 2 side, the second wall 46b on the base joints 13 and 14 side facing and spaced apart from the first wall 46a, and the first wall 46a and the second wall 46b. And an internal space 46c. The first wall 46a is fixed to the distal end portion of the arm body 45 at the center thereof.

  The rotation actuator 50 is attached to the arm 10. In particular, in the present embodiment, the rotation actuator 50 is attached to the first wall 46 a of the container 46, and is disposed at the distal end portion of the arm 10 as viewed in the entire arm 10. The rotation actuator 50 is, for example, an electric motor. The output shaft 50a of the rotation actuator 50 is disposed in the internal space 46c of the container 46, and the housing 50b of the rotation actuator 50 protrudes from the outer surface of the first wall 46a to the same side as the arm body 45. A power transmission mechanism 51 that transmits the rotational power of the rotation actuator 50 to the tip arm 47 is housed in the internal space 46 c of the housing body 46.

  The power transmission mechanism 51 includes a counter shaft 53 that is rotatably supported by the housing 46 and a rotation reduction gear 52 that decelerates the rotational power of the rotation actuator 50 and transmits the rotation power to the counter shaft 53. In the present embodiment, the counter shaft 53 is disposed in parallel with the output shaft 50 a of the rotation actuator 50. The rotation reduction gear 52 may be a spur gear train interposed between the output shaft 50 a and the counter shaft 53. The rotation speed reducer 53 in this case has a drive gear 52a fixed on the output shaft 50a, and a driven gear 52b fixed on the counter shaft 53 and meshed with the drive gear 52a. The rotation speed reducer 52 is not limited to a spur gear train in the same manner as the swinging speed reducer 42, and other power transmission mechanisms may be applied.

  The counter shaft 52 has a protruding end portion 52 a that penetrates through the second wall 46 b of the container 46 and protrudes from the second wall 46 b to the outside of the container 46. The distal arm 47 is fixed to the protruding end 53 a of the counter shaft 53. As described above, the proximal joints 13 and 14 are provided at both ends of the distal arm 47. The axis of the counter shaft 53 passes through an intermediate point of the distal arm 47 and is orthogonal to a line connecting the centers of the proximal joints 13 and 14.

  When the rotation actuator 50 operates, the rotational power of the rotation actuator 50 is transmitted to the counter shaft 52 via the rotation reduction gear 53. When the counter shaft 53 is driven to rotate, the tip arm 47 rotates around the axis of the counter shaft 53. As a result, the inclination angle of the upper link 17 changes, and the pair of proximal joints 13 and 14 revolve around the axis of the counter shaft 53. Thus, the axis of the counter shaft 53 forms the above-described rotation axis 10b.

  According to the arrangement of the rotation actuator 50, the rotation actuator 50 is attached to the arm 10, particularly the tip of the arm 10. For this reason, the power transmission mechanism 51 can be reduced in size, and the weight of the member rotated by the rotational power of the rotation actuator 50 is reduced. For this reason, the required torque of the rotation actuator 50 can be reduced, and the rotation actuator 50 can be downsized. In particular, in this embodiment, as described above, the posture of the bracket 3 can be accurately controlled without greatly reducing the rotational power of the rotation actuator 50. For this reason, a structure in which the power transmission mechanism 51 is accommodated in the accommodation body 56 provided at the distal end portion of the arm 10 can be realized relatively easily. Further, since the housing 50b of the rotation actuator 50 is exposed outside the arm 10, maintenance of the rotation actuator 50 and the power transmission mechanism 51 can be easily performed.

(Energizing unit)
FIG. 8 is a front view showing a part of the arm mechanism 4 shown in FIG. As shown in FIG. 8, the arm mechanism 4 includes an urging unit 60 for urging the pair of links 11 and 12 toward each other. As shown in FIG. 1, two urging units 60 that are separated from each other in the extending direction of the links 11 and 12 are provided for one set of arm mechanisms 4. FIG. 8 shows only the urging unit 60 on the base end side, but since the two urging units 60 have the same structure, detailed descriptions of those on the distal end side are omitted.

  As shown in FIG. 8, the urging unit 60 includes a coil spring 61 disposed between the pair of links 11 and 12, and a first connector 62 that connects one end of the coil spring 61 to the first link 11. And a second connector 63 that connects the other end of the coil spring 61 to the second link 12. The first connector 61 is formed in a V shape or a Y shape in plan view. The first connector 62 has a base end portion 62 a that is swingably connected to one end portion of the coil spring 61, and a tip end portion 62 b that is bifurcated from the base end portion. The first link 11 is sandwiched between bifurcated tip portions 62b, and the bifurcated tip portions 62b are all swingably connected to the first link 11. The pivot of the base end 62a is substantially parallel to the pivot of the distal end 62b. The second connector 63 is the same as the first connector 62, and a base end 63 a that can swing at the other end of the coil spring 61 and a bifurcated tip 63 b that can swing at the second link 12. And have.

  According to the configuration of the urging unit 60, when the sockets 25 and 26 are about to fall off the balls 23 and 24, the links 11 and 12 are about to move away from each other, so that the coil spring 61 is pulled. At this time, the coil spring 61 exerts a resilience in the compressing direction and biases the links 11 and 12 in a direction approaching each other. Thereby, it is possible to prevent the sockets 25 and 26 from falling off the balls 23 and 24.

  When the arm 10 rotates and the upper link 17 tilts, the links 11 and 12 and the proximal joints 13 and 14 are parallel to the extending direction of the links 11 and 12 (the Z axis in FIG. 6). ) May be twisted around. The coil spring 61 is exposed. For this reason, when the link and the proximal joint are twisted around the Z axis, the coil spring 61 is deformed following the twist. In this way, the urging unit 60 can allow the links 11 and 12 and the proximal joints 13 and 14 to twist around the Z-axis when the arm 10 rotates, and the change in the posture of the bracket 3 is caused by the urging unit 60. It is designed not to be disturbed.

[Second Embodiment]
FIG. 9 is a cross-sectional view of the arm 210 showing the arrangement of the swing actuator 5 and the rotation actuator 250 according to the second embodiment of the present invention. As shown in FIG. 9, the rotation actuator 250 may be built in the arm 210. In this case, a through hole 246d is provided in the first wall 246a of the container 246, and the rotation actuator 250 is fixed to the first wall 246a so as to close the through hole 246d. The housing 250b of the rotation actuator 250 protrudes from the outer surface of the first wall 246a toward the proximal end of the arm body 245 in the arm body 245. The output shaft 250a of the rotation actuator 250 extends into the internal space 246c of the container 246 through the through hole 246d. The power transmission mechanism 251 does not have the rotation reduction gear as in the first embodiment, but has only the counter shaft 253. The counter shaft 253 is disposed on the same axis as the output shaft 250a, and is connected to the output shaft 250a via a shaft coupling (not shown). Also in the present embodiment, the axis of the counter shaft 253 forms the rotation axis 10b, and the posture of the bracket can be easily and accurately controlled as in the first embodiment.

[Third Embodiment]
FIG. 10 is a cross-sectional view of the arm 310 showing the arrangement of the swing actuator 5 and the rotation actuator 350 according to the third embodiment of the present invention. As shown in FIG. 10, in this embodiment, the rotation actuator 350 is fixed to the deceleration box 341 of the base 2. A power transmission mechanism 351 that transmits the rotational power of the rotation actuator 350 to the mount arm 47 is incorporated in the speed reduction box 341, the swing shaft 343, the arm body 345, and the housing 346. The swing shaft 343 is arranged in the same manner as in the first embodiment, but has an internal space 343a that is open at both ends in order to incorporate the power transmission mechanism 351.

  The rotation actuator 350 is fixed to the reduction box 341, and the output shaft 350 a of the rotation actuator 350 is disposed in the reduction box 341 and extends in parallel with the output shaft 5 a of the swing actuator 5. The housing 350b of the rotation actuator 350 is disposed outside the speed reduction box 341. The power transmission mechanism 351 includes a first rotation speed reducer 352, an intermediate shaft 353, a second rotation speed reducer 354, and an output shaft 355. The first rotation reduction gear 352 is disposed in the reduction box 341. The intermediate shaft 353 is disposed in parallel with the output shaft 350 a of the rotation actuator 350 and is inserted into the internal space 343 c of the swing shaft 343. The first rotation speed reducer 352 may be a spur gear train interposed between the output shaft 350a and the intermediate shaft 353. The first rotation reduction gear 352 in this case has a drive gear 352a fixed on the output shaft 350a, and a driven gear 352b fixed on the intermediate shaft 353 and meshed with the drive gear 352a. The intermediate shaft 353 is disposed on the same axis as the swing shaft 343 and is rotatably supported by the swing shaft 343. The first rotation speed reducer 352 is disposed farther from the arm body 346 than the swinging speed reducer 342. Therefore, the swinging speed reducer 342 has a through hole 342a communicating with the internal space 343c of the swinging shaft 343 so that the intermediate shaft 353 can be inserted therethrough.

  The intermediate shaft 353 passes through the swing shaft 343 and reaches the arm main body 345. The output shaft 355 of the power transmission mechanism 351 extends in the arm body 345 along the longitudinal direction of the arm body 345 and is orthogonal to the intermediate shaft 353. The second rotation reduction gear 354 may be a bevel gear train that is housed in the arm main body 346 and interposed between the intermediate shaft 353 and the output shaft 355. In this case, the second reduction gear 354 includes a drive bevel gear 354a fixed to the end of the intermediate shaft 353, and a driven bevel gear 354b fixed to the end of the output shaft 355 and meshed with the drive bevel gear 354a. And have. The output shaft 355 passes through the arm main body 345 and the housing 346 and is fixed to the tip arm 347. The container 346 has a through hole 346d at the center of the first wall 346a in order to pass through the output shaft 355.

  Thus, the rotation actuator 350 may be attached to the base 2. In this way, it is possible to avoid a load from acting on the rotation actuator 350 when the arm 310 swings.

[Fourth Embodiment]
FIG. 11 is a cross-sectional view of the arm 410 showing the arrangement of the swing actuator 5 and the rotation actuator 350 according to the fourth embodiment of the present invention. As shown in FIG. 11, the arm 410 according to this embodiment includes an arm base 445, an arm main body 446, and a tip arm 47. The distal arm 47 is fixed to the distal end portion of the arm body 446. The swing actuator 5, the speed reduction box 341, the swing speed reducer 342, the swing shaft 343, and the rotation actuator 350 are the same as in the third embodiment.

  The swing shaft 343 is fixed to the arm base 445. An output shaft 350 a of the rotation actuator 350 is disposed in the deceleration box 341. The power transmission mechanism 451 that transmits the rotational power of the rotation actuator 350 to the mount arm 47 includes a first rotation reduction gear 352, an intermediate shaft 353, a second rotation reduction gear 454, and an output shaft 455. The first rotation reduction gear 352 and the intermediate shaft 353 are the same as those in the third embodiment. The end of the intermediate shaft 353 reaches the inside of the arm base 445. The output shaft 455 extends inside the arm base portion 445 perpendicular to the intermediate shaft 353 and is connected to the base end portion of the arm main body 446. The second rotation speed reducer 454 may be a bevel gear train that is housed in the arm base 445 and interposed between the intermediate shaft 353 and the output shaft 455. The second rotation speed reducer 454 in this case includes a drive bevel gear 454a fixed to the end of the intermediate shaft 353, and a driven bevel gear 454b fixed to the end of the output shaft 455 and meshed with the drive bevel gear 454a. And have.

  In this embodiment, when the swing actuator 5 operates, the swing shaft 343 is driven to rotate, and the arm base 445 swings around the swing axis 10 a together with the swing shaft 343. Then, the arm main body 446 connected to the arm base 445 via the output shaft 455 and the tip arm 47 fixed to the arm main body 446 swing together with the arm base 445. When the rotation actuator 350 operates, the output shaft 455 is driven to rotate, and the arm body 446 rotates around the axis of the output shaft 455 together with the output shaft 455. Along with this, the distal arm 47 rotates together with the arm body 446. In the first to third embodiments, only the tip arm of the arms rotates, but a configuration in which the arm main body rotates as in this embodiment may be employed.

[Fifth Embodiment]
FIG. 12 is a front view showing a part of an arm mechanism 504 according to the fifth embodiment of the present invention. As shown in FIG. 12, the pair of proximal joints 513, 514 includes balls 523, 524 provided at both ends of the distal arm 47, and sockets 525, 526 that hold the balls 523, 524. The sockets 525 and 526 may be configured to support the balls 523 and 524 so as to be sandwiched in the vertical direction in a cross-sectional view. In this way, the sockets 525 and 526 are integrally attached to the balls 523 and 524. Then, the possibility that the links 11 and 12 are dropped from the arm 10 can be reduced. Therefore, in this embodiment, the urging unit according to the first embodiment can be omitted. In FIG. 12, the proximal joints 513 and 514 are shown, but the distal joint can be similarly changed.

  Although the embodiment of the present invention has been described above, the above configuration is an example, and can be appropriately changed within the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention has an effect of providing a delta parallel robot that can easily and accurately control the posture of a bracket, and is beneficial when applied to a delta parallel robot.

DESCRIPTION OF SYMBOLS 1 Delta type parallel robot 2 Base 3 Bracket 4 Arm mechanism 5 Swing actuator 9 Work tool 10 Arm 11, 12 Link 13, 14 Proximal joint 15, 16 End joint 17 Upper link 18 Lower link 47 End arm 50 Rotating actuator

Claims (5)

A base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base;
Wherein each arm mechanisms, one arm of which is connected pivotably to the base around the arm pivot axis at the proximal end, and a pair of links sandwiching and said bracket sandwiching the tip end of the arm , Yes a pair of proximal joint for pivotally connected to the pair of links ahead end of each said arm, a pair of tip joint for pivotally connected to the pair of links to each of the bracket, the And the pair of links, the pair of proximal joints and the pair of distal joints are arranged so as to be able to constitute a parallel link,
At least one of the three sets of arm mechanisms is configured such that at least the tip of the arm is rotationally driven around the axis of the arm by a rotation actuator ,
The base further includes an oscillating shaft that is rotatably supported about the arm oscillating axis, and the arm has an arm main body whose base end is fixed to the oscillating shaft, and a distal end of the arm main body. A distal end arm provided on the distal end of the arm, and the distal end arm is sandwiched between the pair of links.
A delta-type parallel robot in which the rotation actuator is attached to the base, and a power transmission mechanism that transmits rotational power of the rotation actuator to the tip arm is built in the swing shaft and the arm body . A base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base;
Each arm mechanism has one arm pivotally connected to the base around the arm swing axis at the base end, and a pair of links that sandwich the tip of the arm and the bracket, A pair of proximal joints that pivotably connect the pair of links to the distal end of the arm, respectively, and a pair of distal joints that pivotally connect the pair of links to the bracket, respectively. The pair of links, the pair of proximal joints and the pair of distal joints are arranged so as to constitute a parallel link,
At least one of the three sets of arm mechanisms is configured such that at least the tip of the arm is rotationally driven around the axis of the arm by a rotation actuator,
The base further includes an oscillating shaft that is rotatably supported about the arm oscillating axis, and the arm has an arm main body whose base end is fixed to the oscillating shaft, and a distal end of the arm main body. A distal end arm provided on the distal end of the arm, and the distal end arm is sandwiched between the pair of links.
The rotation actuator is attached to the base, a power transmission mechanism for transmitting the rotation power of the rotation actuator to the tip arm is built in the swing shaft, and the rotation power is transmitted through the arm body. Ru is transmitted to the distal arm, delta type parallel robot. A base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base;
Each arm mechanism has one arm pivotally connected to the base around the arm swing axis at the base end, and a pair of links that sandwich the tip of the arm and the bracket, A pair of proximal joints that pivotably connect the pair of links to the distal end of the arm, respectively, and a pair of distal joints that pivotally connect the pair of links to the bracket, respectively. The pair of links, the pair of proximal joints and the pair of distal joints are arranged so as to constitute a parallel link,
At least one of the three sets of arm mechanisms is configured such that at least the tip of the arm is rotationally driven around the axis of the arm by a rotation actuator,
The arm includes an arm main body, a tip arm provided at a tip portion of the arm main body, and a container interposed between the arm main body and the tip arm. A first wall to which the tip is fixed, a second wall facing away from the first wall, and an internal space surrounded by the first wall and the second wall;
The rotation actuator is attached to the outer surface of the container , and a power transmission mechanism that transmits the rotational power of the rotation actuator to the tip arm is housed in the internal space of the container, and the output of the power transmission mechanism shaft is fixed to the distal arm outside of the housing body through said second wall, delta type parallel robot. A base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base;
Each arm mechanism has one arm pivotally connected to the base around the arm swing axis at the base end, and a pair of links that sandwich the tip of the arm and the bracket, A pair of proximal joints that pivotably connect the pair of links to the distal end of the arm, respectively, and a pair of distal joints that pivotally connect the pair of links to the bracket, respectively. The pair of links, the pair of proximal joints and the pair of distal joints are arranged so as to constitute a parallel link,
At least one of the three sets of arm mechanisms is configured such that at least the tip of the arm is rotationally driven around the axis of the arm by a rotation actuator,
The arm includes an arm main body, a tip arm provided at a tip portion of the arm main body, and a container interposed between the arm main body and the tip arm. A first wall to which the tip is fixed, a second wall facing away from the first wall, and an internal space surrounded by the first wall and the second wall;
The rotation actuator is built in the arm body, a power transmission mechanism that transmits the rotational power of the rotation actuator to the tip arm is accommodated in the internal space of the housing body, and an output shaft of the power transmission mechanism is the first shaft. through the second wall are secured to the distal arm outside of the housing body, delta type parallel robot. A base, a bracket for attaching a tool, and three sets of arm mechanisms for connecting the bracket to the base;
Each of the arm mechanisms includes one arm that is swingably connected to the base at a base end portion, a pair of links that sandwich the distal end portion of the arm and the bracket, and the pair of links, respectively. A pair of proximal joints rotatably connected to the distal end of the arm, and a pair of distal joints rotatably connecting the pair of links to the bracket, the pair of links, A pair of proximal joints and the pair of distal joints are arranged so that parallel links can be configured,
At least one of the three sets of arm mechanisms is configured such that at least the tip of the arm is rotationally driven around the axis of the arm by a rotation actuator,
The pair of proximal joints includes a pair of balls provided at both ends of the distal end of the arm, and a pair of sockets provided at the proximal ends of the pair of links, the sockets correspondingly A delta-type parallel robot that holds the ball in such a manner as to sandwich the ball vertically.

Images