JP2015083324A - Work insertion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a configuration which enables an operation of inserting a work 1 through simple control without increase of the accuracy of positioning an arm 12 as a moving part.SOLUTION: A controller 14 moves an arm 12 in a search range consisting of a specified range including an insertion hole 3 as an insertion position for the work 1 in a state where the work 1 held by a hand 11 serving as a holding part is pressed toward a mating member 2. A spring part 13 serving as a connection part moves the hand 11 so as to follow the arm 12 in a state where the work 1 held by the hand 11 does not match the insertion hole 3. In a state where the work 1 held by the hand 11 matches the insertion hole 3, the spring part 13 makes the arm 12 to be relatively movable with respect to the hand 11 within the search range 4.

Description

  The present invention relates to a workpiece insertion device that performs an assembly operation of machine parts, particularly an operation of inserting a workpiece into an insertion hole of a mating member.

  2. Description of the Related Art Conventionally, there is an assembly work robot (work insertion device) that automatically inserts, for example, a bar-shaped workpiece gripped by a hand (gripping portion) provided at the tip of an arm (moving portion) into an insertion hole of a counterpart member. For example, such a robot searches for an insertion hole (insertion position) into which the workpiece is inserted while pressing the workpiece held by the hand against the counterpart member. As this search method, a method has been proposed in which the insertion position is searched by changing the search direction within the search range, and the insertion position is searched by detecting a change in pressure pressing the workpiece against the counterpart member (patent) Reference 1).

  In addition, a force / moment sensor is provided at the tip of the arm, and the arm tip has a control mechanism that operates flexibly with respect to external force. It detects the force / moment during search and moves the arm in a direction that reduces the moment. A robot has also been proposed (Patent Document 2).

JP 2004-167651 A JP 2009-61550 A

  In the case of the configuration described in Patent Documents 1 and 2 described above, since the sensor is used to search for the insertion position, processing such as data acquisition and determination from the sensor is necessary, and further the data change position Therefore, complicated control such as stopping the robot operation is required. Also, unless the deviation between the position searched by the sensor and the actual insertion position is made as small as possible, the workpiece cannot be surely inserted into the insertion hole, so the arm positioning accuracy needs to be improved.

  In view of such circumstances, the present invention has been invented to realize a configuration in which a work insertion operation can be performed with simple control without increasing the positioning accuracy of a moving part.

  The present invention provides a gripping part capable of gripping a work, a pressing part for pressing the work gripped by the gripping part toward a mating member, a moving part for moving the gripping part, and the moving part. A control unit that moves within a predetermined range on a virtual plane that includes the insertion position of the workpiece and is orthogonal to the pressing direction by the pressing unit, while the workpiece held by the pressing member is pressed against the mating member, and is held by the holding unit In a state where the workpiece does not coincide with the insertion position, the gripping portion is moved following the moving portion, and in a state where the workpiece gripped by the gripping portion coincides with the insertion position, the moving portion is A workpiece insertion device comprising: a connection portion that connects the grip portion and the moving portion so as to be relatively movable with respect to the grip portion within a predetermined range.

  In the case of the present invention, the gripping portion is moved following the moving portion in a state where the workpiece does not coincide with the insertion position, and the moving portion can move relative to the gripping portion in the coincident state. For this reason, in a state where the workpiece does not coincide with the insertion position, the workpiece moves within a predetermined range including the insertion position, and the workpiece coincides with the insertion position during this movement. At this time, since the moving part can move relative to the gripping part, even if the workpiece matches the insertion position, the state where the workpiece matches the insertion position is maintained (positioned). As a result, the work can be inserted with simple control without increasing the positioning accuracy of the moving part.

The schematic diagram of the workpiece insertion apparatus which concerns on the 1st Embodiment of this invention. The schematic diagram which shows the search range of the insertion position which concerns on 1st Embodiment. The flowchart which shows the flow of the workpiece | work insertion operation | movement which concerns on 1st Embodiment. The schematic diagram which shows the insertion operation | movement of the workpiece | work which concerns on 1st Embodiment in order. The schematic structure of the parallel link robot which concerns on the 2nd Embodiment of this invention is shown, (a) is a front view, (b) is a side view. Similarly, (a) shows a schematic configuration of a parallel link robot, and (b) is an enlarged perspective view of a configuration around an output member. (A) is an enlarged perspective view of an example of a joint portion with two degrees of freedom, and (b) is a schematic diagram showing a state in which a bridge member is bridged over two links in a configuration using a joint portion with three degrees of freedom. . The perspective view which looked at the parallel link robot of 2nd Embodiment from the angle different from Fig.6 (a). The top view which abbreviate | omitted a part of parallel link robot which shows three examples of the drive state of the rotation part by the 4th motor of 2nd Embodiment. The perspective view which cut | disconnects and shows the structure around the speed increase rotation mechanism provided in the output member of 2nd Embodiment. Sectional drawing of the speed-increasing rotation mechanism similarly provided in the output member. The top view which shows the planetary gear mechanism which comprises a speed-up rotation mechanism. The block diagram which shows a part of control system of the parallel link robot which concerns on 2nd Embodiment. The figure which shows an example of the pulse signal of the 2 phase excitation system output to a stepping motor in 2nd Embodiment. The schematic structure of the parallel link robot which concerns on the 3rd Embodiment of this invention is shown, (a) is a front view, (b) is a side view. Similarly, (a) shows a schematic configuration of a parallel link robot, and (b) is an enlarged perspective view of a configuration around an output member. The perspective view which looked at the parallel link robot of 3rd Embodiment from the angle different from Fig.16 (a). The top view which abbreviate | omitted a part of parallel link robot which shows the 3 examples of the drive state of the rotation part by the 4th motor of 3rd Embodiment. The perspective view which cut | disconnects and shows the structure around the speed increase rotation mechanism provided in the output member of 3rd Embodiment. Sectional drawing of the speed-increasing rotation mechanism similarly provided in the output member.

<First Embodiment>
A first embodiment of the present invention will be described with reference to FIGS. First, the structure of the workpiece insertion apparatus (assembly work robot) 10 of this embodiment will be described with reference to FIGS. 1 and 2.

[Configuration of workpiece insertion device]
As shown in FIG. 1, the workpiece insertion device 10 of the present embodiment includes a hand 11 as a gripping portion, an arm 12 as a moving portion, a spring portion 13 as a pressing portion, and a control device 14 as a control portion. Is provided. The hand 11 is a grip portion that can grip, for example, a rod-shaped workpiece 1, and includes fingers 11 a as a plurality of grip members that can move in the direction in which the workpiece 1 is gripped. That is, the plurality (two in this embodiment) of fingers 11a are provided so as to be close to or separated from each other. The hand 11 clamps (grips) the workpiece 1 between the pair of fingers 11a by moving so that the pair of fingers 11a approach each other. On the other hand, the gripping of the workpiece 1 is released (released) by moving the pair of fingers 11 a away from this state. In addition, you may comprise the finger 11a by three or more.

  Such a hand 11 has a drive mechanism (not shown) that is driven by the pressure of a fluid such as air pressure or hydraulic pressure, and moves the finger 11a as described above by this drive mechanism. The drive mechanism may be another actuator such as an electric motor. Such a drive mechanism is driven in accordance with a control command sent from the control device 14 described later. That is, the hand 11 grips and releases the workpiece 1 according to a command from the control device 14.

  The arm 12 is a moving unit that moves the hand 11 and is driven by a drive source such as an electric motor (not shown). Such an arm 12 has a direction in which the workpiece 1 gripped by the hand 11 is inserted (or fitted) into an insertion hole 3 provided in a counterpart member (object) 2 and a direction perpendicular to the insertion direction. It is movable. That is, the arm 12 can move the work gripped by the hand 11 in the X direction and the Y direction (direction orthogonal to the insertion direction) and the Z direction (insertion direction) shown in FIG. In the present embodiment, the Z direction is the vertical direction, and the X and Y directions are the horizontal direction.

  The spring portion 13 is configured by a coil spring, and is a pressing portion that presses the workpiece 1 held by the hand 11 toward the mating member 2, and is disposed between the hand 11 and the arm 12. As will be described later, the arm 12 is driven to press the workpiece 1 gripped by the hand 11 against the mating member 2 in order to search for the insertion position (insertion hole 3) of the workpiece 1. At this time, the spring portion 13 provided between the arm 12 and the hand 11 is elastically compressed, and the work 1 held by the hand 11 is pressed against the counterpart member 2 by the elastic restoring force of the spring portion 13. . In the present embodiment, since the workpiece 1 is pressed against the mating member 2 by the spring portion 13 in this way, the pressing force can be generated stably even if the distance between the arm 12 and the mating member 2 is not strictly regulated. It is done. At the same time, the spring portion 13 acts as a cushioning material, so that the workpiece 1 can be smoothly moved while being pressed against the mating member 2, and the workpiece 1 is strongly abutted against the mating member 2 and is damaged. Can be suppressed.

  The control device 14 can control the drive source of the arm 12 to move the arm 12 in the X, Y, and Z directions described above. In the present embodiment, when performing a search operation to be described later, the control device 14 moves the arm 12 within a predetermined range with the work 1 held by the hand 11 pressed against the counterpart member 2. As shown in FIG. 2, the predetermined range includes an insertion hole 3 (insertion position of the workpiece 1) for inserting the workpiece 1 provided in the counterpart member 2, and a pressing direction (insertion direction, Z direction) by the spring portion 13. This is a search range 4 on an orthogonal virtual plane (on an XY plane).

  The search range 4 is a range set in advance for inserting the workpiece 1 into the insertion hole 3 of the counterpart member 2. Specifically, the search range 4 is determined by considering the position error of the insertion hole 3 with respect to the mating member 2 and the mounting error of the mating member 2 to the work insertion device 10. It is set within the range that exists with respect to the origin. Further, such a search range 4 is set to be equal to or less than a range in which the arm 12 and the hand 11 described later can be relatively moved. In FIG. 2, it is set within a circle having a radius ΔL from the center of the insertion hole 3 (theoretical position of the insertion hole 3) (that is, a range in which the insertion hole 3 is necessarily present even if the above-mentioned error is taken into consideration). The search range 4 can be arbitrarily set, and the shape of the range is not limited to a circle. In short, it may be set so that the insertion position of the workpiece 1 is always within the range. However, if the range is too wide, it takes a long time to search for the insertion position, and it is necessary to increase the distance that allows relative movement between the arm 12 and the hand 11 to be described later. It is preferable to narrow the range as much as possible.

  In the present embodiment, the control device 14 moves the arm 12 within the search range 4 in accordance with a preset programmed operation in a state where the workpiece 1 is pressed against the counterpart member 2. For example, the movement of the arm 12 may be made to gradually move outward from the center of the search range 4 so as to draw a vortex, or may be orthogonal to the predetermined direction while reciprocating in a predetermined direction on the XY plane. You may make it move to a direction. In addition, other conventionally known indexing operations for the insertion position are also applicable.

  Further, the control device 14 causes the arm 12 to perform a predetermined operation according to the above-described program, and then releases the grip of the work 1 by the hand 11. The hand 11 has an urging spring 15 as urging means for urging the workpiece 1 whose grip is released toward the counterpart member 2. In the present embodiment, the urging spring 15 is constituted by a coil spring, but may be another elastic member such as rubber. In any case, the urging spring 15 is provided between the fingers 11 a of the hand 11 and is elastically compressed between the work 1 and the hand 11 in a state where the hand 11 grips the work 1. When the hand 11 releases the grip of the work 1, the hand 11 is elastically restored to bias the work 1 toward the mating member 2.

  In the case of this embodiment, the hand 11 and the arm 12 are connected by a spring portion 13 as a connecting portion. That is, the spring part 13 serves as both a connection part and a pressing part. Such a spring portion 13 may be composed of other elastic members such as rubber, for example, in addition to the coil spring. The spring constant is set.

  First, in the state where the workpiece 1 held by the hand 11 does not coincide with the insertion position (insertion hole 3), the hand 11 is moved following the arm 12. In addition, in a state where the workpiece 1 held by the hand 11 coincides with the insertion position, the arm 12 can be moved relative to the hand 11 within the search range 4 (within a predetermined range). The distance that allows the relative movement between the arm 12 and the hand 11 by the spring portion 13 is at least the distance from the center of the insertion hole 3 provided in the counterpart member 2 to the farthest position in the search range. In the present embodiment, the spring portion 13 is set so as to be relatively movable by the radius ΔL described above. The spring portion 13 is set so that the arm 12 can move in all directions on the XY plane with respect to the hand 11.

[Work insertion operation]
Next, the operation of inserting the workpiece 1 using the workpiece insertion device 10 described above will be described with reference to FIGS. First, when the insertion work is started (S1), the control device 14 causes the hand 11 to grip the workpiece 1. At this time, the work 1 is gripped in a state where the urging spring 15 provided on the hand 11 is elastically compressed between the work 1 and the hand 11. And in order to search the insertion position of the workpiece | work 1, as shown to Fig.4 (a), the control apparatus 14 moves the arm 12 so that the workpiece | work 1 hold | gripped by the hand 11 may be located in the above-mentioned search range 4. FIG. It moves on the counterpart member 2 (S2).

  Next, the arm 12 is lowered by the control device 14 and the work 1 is pressed to a position within the search range 4 of the counterpart member 2. At this time, the spring portion 13 provided between the arm 12 and the hand 11 is elastically compressed, and the work 1 is pressed against the mating member 2 through the hand 11 (S3). In this state, as shown in FIG. 4B, the control device 14 moves the arm 12 within the search range 4 (executes a search operation) (S4). At this time, since the hand 11 is connected by the arm 12 and the spring portion 13, the hand 11 moves following the arm 12.

  Then, this moving operation is repeated a specified number of times (S5). When this moving operation is performed, the workpiece 1 passes through the insertion hole 3 and the workpiece 1 coincides with the insertion hole 3. At this time, due to the compliance function of the spring portion 13 provided between the arm 12 and the hand 11, the end portion of the workpiece 1 is easily aligned with the insertion hole 3. In general, in the case of a fitting component, the diameter of the insertion hole 3 is set to be slightly larger than the diameter of the workpiece 1, and a guide portion such as a chamfer is provided at the inlet of the insertion hole 3 or the end surface of the workpiece 1. Is formed so that the workpiece 1 can easily enter the insertion hole 3. In any case, when the end of the work 1 is aligned with the insertion hole 3 (the work is aligned with the insertion position), the work 1 is pressed against the mating member 2 by the spring portion 13, so that the pressing force causes the work 1 Is slightly inserted into the insertion hole 3.

  When the work 1 is slightly inserted into the insertion hole 3 as described above and the above-mentioned prescribed number of operations are not completed, the arm 12 continues to move. On the other hand, the hand 11 that grips the work 1 partially inserted into the insertion hole 3 tends to stay at that position due to the load caused by the engagement between the insertion hole 3 and the work 1. At this time, the hand 11 that holds the workpiece 1 and the arm 12 are connected to each other by the spring portion 13 so as to be relatively movable as described above. Therefore, as shown in FIG. Move relative to it. And the state in which the workpiece | work 1 corresponded with the insertion hole 3 is maintained (positioned). In other words, although the arm 12 is moving, the hand 11 can be kept at that position, and the coincidence state with the insertion position of the workpiece 1 can be maintained.

  Next, when the specified number of operations (predetermined operation) are completed, the control device 14 releases the grip of the work 1 by the hand 11 as shown in FIG. 4D (S6). At this time, the biasing spring 15 provided in the hand 11 assists (assists) the insertion of the workpiece 1 into the insertion hole 3, and the workpiece 1 is inserted into the insertion hole 3. Note that the urging spring 15 may be omitted if the assist is not necessarily required depending on the shape and mass of the work 1. After the hand 11 is opened, as shown in FIG. 4E, the control device 14 raises the arm 12 (S7), and the insertion operation is completed (S8).

  In the case of the present embodiment, as described above, the hand 11 is moved following the arm 12 in a state where the workpiece 1 does not coincide with the insertion position, and the arm 12 can be moved relative to the hand 11 in the coincidence state. The spring portion 13 is For this reason, as described above, when the workpiece 1 does not coincide with the insertion position, the workpiece 1 moves within a predetermined range including the insertion position, and the workpiece 1 coincides with the insertion position during this movement. That is, the end portion of the work 1 coincides with the insertion hole 3. At this time, since the arm 12 can move relative to the hand 11, even if the end portion of the workpiece 1 coincides with the insertion hole 3, the state where the workpiece 1 coincides with the insertion hole 3 is maintained (positioned). ).

  Thus, in this embodiment, since the position of the workpiece 1 after the insertion position is determined does not depend on the position accuracy of the arm 12, it is not necessary to increase the positioning accuracy of the arm 12. Moreover, since it is not necessary to perform position correction by the sensor, the work 1 can be inserted by simple control. Further, it is not necessary to use a special sensor such as a pressure sensor or a force / moment sensor to search for the insertion position. For this reason, the cost of the workpiece insertion apparatus 10 can be reduced.

  In the above description, the pressing portion and the connecting portion are shared by the spring portion 13, but they may be configured separately. For example, a pressing portion that presses the workpiece 1 toward the mating member 2 is provided on the arm 12, and a member that does not function as a pressing portion but functions as a connection portion is provided between the arm 12 and the hand 11. You may do it. Specifically, a pressing member such as a biasing spring is provided between the drive unit of the arm 12 and the portion of the arm 12 that supports the hand 11. On the other hand, between the portion of the arm 12 that supports the hand 11 and the hand 11, for example, a wire, rubber, or a rod of metal, resin, or the like that has a certain degree of rigidity and elasticity that satisfies the condition as a connecting portion An elastic member such as a material is provided.

  In this case, the pressing portion may be configured by a driving source that moves the arm 12 toward the counterpart member 2, and the connecting portion provided between the arm 12 and the hand 11 may not be an elastic member. For example, the following meshing mechanism may be used. That is, the meshing mechanism meshes when the workpiece 1 is pressed against the mating member 2 and does not coincide with the insertion position, and allows the hand 11 to move following the arm 12. On the other hand, the meshing mechanism releases the meshing when the work 1 coincides with the insertion position and the hand 11 is slightly separated from the arm 12 toward the mating member 2, so that the hand 11 and the arm 12 can move relative to each other.

  Furthermore, in the above description, the case where the rod-shaped workpiece is inserted into the insertion hole of the counterpart member has been described. However, the shape of the workpiece is not limited to the rod shape, and the portion into which the workpiece is inserted is not limited to the circular hole. Other shapes such as holes or groove shapes may be used. In short, when the workpiece and the mating member are in an insertion or fitting relationship, when the workpiece pressed against the mating member matches the insertion position, the workpiece moves to the mating member side, so that the insertion or fitting is performed. The present invention is applicable if it is performed.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the workpiece insertion apparatus 10 described in the first embodiment is applied to a parallel link robot. In the following description, although detailed illustration and description are omitted, the output member 103 includes the configuration such as the gripping portion and the connecting portion described in the first embodiment. That is, an end effector 104 of the output member 103, which will be described later, corresponds to the hand 11 as a gripping portion, and the plurality of arms 109, 110, and 112 correspond to the arm 12 as a moving portion. A connection portion (not shown) that connects the end effector 104 and the plurality of arms 109, 110, and 112 to the output member 103 is provided. In addition, the plurality of motors 107, 108, and 111 that drive the plurality of arms 109, 110, and 112, and the end effector 104 are commands from the control device 14 (not illustrated) described in the first embodiment. It works by.

  In addition, when the cross-sectional shape of the workpiece and the shape of the portion into which the workpiece is inserted are not circular, for example, in the case of a rectangle, an ellipse, a polygon, etc. Cannot insert at the part to insert. For this reason, in this embodiment, the end effector 104 that grips the workpiece can be rotated, and the cross-sectional shape of the workpiece can be matched with the shape of the portion to be inserted. For example, before the search operation for inserting the workpiece, the rotation angle of the end effector 104 is adjusted so that the user matches the cross-sectional shape of the workpiece with the shape of the portion to be inserted. Then, the search operation is started while maintaining this angle. Alternatively, the rotation angle of the end effector 104 is changed at any time during the search operation so that the cross-sectional shape of the workpiece matches the shape of the portion to be inserted and the position of the workpiece is matched with the portion to be inserted during the search operation. Hereinafter, a specific configuration for realizing such a configuration will be described in detail.

  As shown in FIGS. 5 and 6, the parallel link robot 100 includes a base member 100A as a fixed member, an output member 103, a plurality of motors 107, 108, 111, 113, and a plurality of arms 109, 110, 112. 119. The first motor 107 corresponds to the first actuator, the second motor 108 corresponds to the second actuator, the third motor 111 corresponds to the third actuator, and the fourth motor 113 corresponds to the fourth actuator. 109 corresponds to the first arm, 110 corresponds to the second arm, 112 corresponds to the third arm, and 119 corresponds to the fourth arm.

  The base member 100A includes a horizontal plate 101 arranged in a substantially horizontal direction and a vertical plate 102 provided in a substantially vertical direction from the horizontal plate 101, and supports the plurality of motors 107, 108, 111, 113 described above. To do. The plurality of motors 107, 108, 111, 113 are respectively fixed at predetermined positions on the vertical plate 102. In the present embodiment, the third motor 111 is located above the vertical center of the vertical plate 102 in the vertical direction, and the first motor 107 and the second motor 107 are respectively disposed on both sides of the vertical direction intermediate portion of the vertical plate 102 across the width direction center. A motor 108 and a fourth motor 113 are arranged. A workpiece or the like is disposed on the horizontal plate 101.

  The output member 103 is a manipulator for mounting an end effector 104 such as a robot hand that holds and moves a workpiece. A link mechanism constituting a plurality of arms, which will be described later, is coupled to the output member 103, and a first shaft (first shaft portion) 105 as an output shaft that supports the end effector 104 is provided coaxially. A second shaft (second shaft portion) 106 that intersects the first shaft 105 is fixed to the first shaft 105. In the present embodiment, the second shaft 106 is disposed substantially parallel to the vertical plate 102 and is orthogonal to the first shaft 105. The first shaft 105 is disposed in a substantially vertical direction, and the second shaft 106 is disposed in a substantially horizontal direction. Further, the upper end of the first shaft 105 in the vertical direction is coupled to the horizontal center of the second shaft 106.

[Positioning of output member]
First, a configuration for positioning the output member 103 by the parallel link robot 100 will be described with reference to FIGS. The first arm 109 and the second arm 110 are disposed between the output member 103 and the first motor 107 and between the output member 103 and the second motor 108, respectively. The first arm 109 and the second arm 110 hold the first shaft 105 from both sides. Then, the output member 103 is moved in a direction intersecting the first shaft 105 (substantially horizontal direction) by driving the first motor 107 and the second motor 108. Strictly speaking, when the third motor 111 is stopped, the output member 103 is moved on a virtual spherical surface by the first motor 107 and the second motor 108.

  The third arm 112 is provided between the output member 103 and the third motor 111. The third arm 112 holds the output member 103 from above in the vertical direction. Then, the output member 103 is moved in a direction substantially parallel to the first shaft 105 by driving the third motor 111. Strictly speaking, when the first motor 107 and the second motor 108 are stopped, the output member 103 moves on a virtual arc by driving the third motor 111. The output member 103 can be positioned in a predetermined space by driving the first motor 107, the second motor 108, and the third motor 111. The first arm 109, the second arm 110, and the third arm 112 constitute a holding unit that holds the posture of the output member 103. Further, the holding means and the output member 103 constitute a parallel link structure. More specific description will be given below.

  The first motor 107 as a first actuator is a rotary actuator that positions the first link shaft 107b by rotating the first rotating arm 107a in a substantially horizontal direction. The second motor 108 as a second actuator is a rotary actuator that positions the second link shaft 108b by rotating the second rotary arm 108a in a substantially horizontal direction. In this embodiment, the length of the 1st rotation arm 107a and the length of the 2nd rotation arm 108a are made the same.

  The first link shaft 107b and the second link shaft 108b are substantially parallel to the rotation shaft of the first motor 107 and the rotation shaft of the second motor 108, respectively, and cannot be tilted. It is provided at the tip of the two-rotating arm 108a. In the present embodiment, since the rotation shafts of the first motor 107 and the second motor 108 are disposed substantially parallel to the first shaft 105, the first link shaft 107b and the second link shaft 108b are also the first shaft 105. Are arranged substantially in parallel.

  The first arm 109 is composed of a plurality of first links 109 a that are spaced apart from each other in a direction parallel to the first shaft 105 and arranged in parallel with each other. In the present embodiment, the first arm 109 is constituted by two first links 109a having the same length. Such a first arm 109 has one end pivoted about the first shaft 105 with respect to the output member 103 and an axis orthogonal to the arrangement direction of the first shaft 105 and the first arm 109. It is connected in a state having two degrees of freedom that allows rotation around the center. Further, the other end is connected to a first link shaft 107 b provided in a non-tiltable manner on a first rotating arm 107 a serving as a drive unit of the first motor 107. Thereby, the 1st arm 109 comprises the parallel link mechanism.

  Specifically, one end of each of the two first links 109a is connected to the first shaft 105 that supports the end effector 104 by a joint portion 109b having two degrees of freedom, and the other end is connected to the first link shaft 107b by two. They are connected by a joint portion 109c having a degree of freedom. Here, the joint portion 109c can be rotated around the first link shaft 107b, and can be rotated around an axis orthogonal to the arrangement direction of the first link shaft 107b and the first link 109a. is there.

  That is, the two first links 109a have both ends connected to the first shaft 105 and the first link shaft 107b with two degrees of freedom, respectively. The first shaft 105, the first link shaft 107b, and the two first links 109a constitute a parallel link mechanism. As a result, the first shaft 105 that supports the end effector 104 and the first link shaft 107b provided so as not to tilt are always kept parallel. The attitude (tilt) of the end effector 104 is held constant (substantially in the vertical direction) regardless of the position of the first rotating arm 107a.

  The second arm 110 includes at least one second link 110 a connected correspondingly between a pair of connection portions (joint portions 109 b) of the first arm 109 with respect to the first shaft 105. In the present embodiment, the second arm 110 is configured by one second link 110a. Further, the length of one second link 110 a is the same as the length of the two first links 109 a of the first arm 109. In such a second arm 110, one end of the second arm 110 rotates about the first shaft 105 with respect to the output member 103, and an axis orthogonal to the arrangement direction of the first shaft 105 and the second arm 110. It is connected in a state having two degrees of freedom that allows rotation around the center. Further, the other end is connected to a second link shaft 108b provided in a non-tiltable manner on a second rotating arm 108a as a drive unit of the second motor 108.

  Specifically, one second link 110a has one end connected to the first shaft 105 supporting the end effector 104 by a joint portion 110b with two degrees of freedom, and the other end connected to the second link shaft 108b with two degrees of freedom. The joint part 110c is connected. Here, the joint portion 110c can rotate around the second link shaft 108b and can rotate around an axis orthogonal to the direction in which the second link shaft 108b and the second link 110a are disposed. is there. In other words, one second link 110a is connected at both ends to the first shaft 105 and the second link shaft 108b with two degrees of freedom. Thereby, the 2nd arm 110 comprises the link mechanism.

  The third motor 111 as the third actuator is a rotary actuator that positions the third link shaft 111b by rotating the third rotating arm 111a in a substantially vertical direction. The third link shaft 111b is provided at the tip of the third rotating arm 111a so as to be substantially parallel to the rotating shaft of the third motor 111 and not tiltable. In the present embodiment, since the rotation shaft of the third motor 111 is disposed substantially parallel to the second shaft 106, the third link shaft 111 b is also disposed substantially parallel to the second shaft 106.

  The third arm 112 includes a plurality of third links 112a that are spaced apart from each other in a direction parallel to the second shaft 106 and arranged in parallel with each other. In the present embodiment, the third arm 112 is constituted by two third links 112a having the same length. Such a third arm 112 has one end pivoted about the second shaft 106 with respect to the output member 103 and an axis orthogonal to the arrangement direction of the second shaft 106 and the third arm 112. It is connected in a state having two degrees of freedom that allows rotation around the center. Further, the other end is connected to a third link shaft 111 b provided in a non-tiltable manner on a third rotating arm 111 a as a drive unit of the third motor 111. Thereby, the 3rd arm 112 comprises the parallel link mechanism.

  Specifically, one end of each of the two third links 112a is connected to the second shaft 106 by a two-degree-of-freedom joint portion 112b, and the other end is connected to the third link shaft 111b by a two-degree-of-freedom joint portion 112c. Connected with. Here, the joint portion 112c can rotate around the third link shaft 111b, and can rotate around an axis orthogonal to the direction in which the third link shaft 111b and the third link 112a are disposed. is there. The pair of third links 112a of the third arm 112 are connected at symmetrical positions in the horizontal direction from the portion where the first shaft 105 of the second shaft 106 is joined.

  That is, the two third links 112a are connected at both ends to the second shaft 106 and the third link shaft 111b with two degrees of freedom. The second shaft 106, the third link shaft 111b, and the two third links 112a constitute a parallel link mechanism. As a result, the second shaft 106 that supports the end effector 104 and the third link shaft 111b provided so as not to tilt are always kept parallel. Then, no matter which position the third rotating arm 111a rotates, the rotation of the end effector 104 around the first shaft 105 is constrained and the orientation is kept constant.

  The two-degree-of-freedom joint portions 109b, 109c, 110b, 110c, 112b, and 112c illustrated as circular joints in FIGS. 5 and 6 preferably have the structure illustrated in FIG. 7A. In the joint portion of FIG. 7A, the degree of freedom of rotating around the support shaft indicated by the arrow A and one rotation or more and rotation within a predetermined angle range indicated by the arrow B with the axis perpendicular to the support shaft as the rotation axis. Has the freedom to move. These joint portions have no functional problem as long as they have at least two degrees of freedom, but joints having three degrees of freedom such as a ball joint and a rod end joint may be used. Thereby, it is possible to make the joint part itself compact. However, in this case, as shown in FIG. 7B, bridge members 201 and 202 are required as restricting members for restricting rotation around the axis of the link in order to prevent twisting of the parallel link mechanism. .

  The bridge members 201 and 202 are disposed near both ends of the two links 203 and 204 so as to be spanned by the two links 203 and 204, respectively. Such bridge members 201 and 202 have axes orthogonal to the links 203 and 204, respectively, and are connected to the links 203 and 204 by rotatably supporting the links 203 and 204 on the axes. This prevents rotation of the link around its axis and allows the two links to move relative to each other in the arrangement direction. And even if two links are connected by a joint part with three degrees of freedom, the degree of freedom around the link axis is constrained, and as a result, an arm composed of two links is connected with two degrees of freedom. can do. Since the two links are relatively movable in the arrangement direction, the two links are maintained in a parallel state and are orthogonal to the axis to which the two links are connected and the arrangement direction of the links. Rotation around the axis is possible.

  For example, each of the two third links 112a constituting the third arm 112 can rotate about the axis of the third link 112a with respect to the output member 103 in addition to the two degrees of freedom described above. Connect with a degree of freedom. In this case, the two third links 112a can be moved relative to each other in the direction in which the third arm 112 is disposed, and the rotation of the respective third links around the axis is made impossible. The members 201 and 202 are spanned. Accordingly, the third arm 112 is connected to the output member 103 and the third link shaft 111b with two degrees of freedom. The same applies to the first arm 109.

  In this embodiment, the angle formed by the first axis 105 and the second axis 106 is 90 degrees and is orthogonal to each other, but may be three-dimensionally orthogonal or 90 degrees. Not limited to this, they may be arranged at a predetermined angle.

  As described above, in this embodiment, the end effector 104 attached to the output member 103 is in a certain posture (tilt) by the parallel link mechanism formed by the first arm 109 and the parallel link mechanism formed by the third arm 112. ) And orientation are supported.

  In the case of this embodiment configured as described above, the output member 103 is substantially horizontal by driving the first rotating arm 107a by the first motor 107 and driving the second rotating arm 108a by the second motor 108. Move in the direction. Further, when the output member 103 is moved in the vertical direction by driving the third rotating arm 111a by the third motor 111, the first arm 109 and the second arm 110 are displaced from the horizontal. For this reason, the position of the output member 103 in the three-dimensional space (predetermined space) is determined by considering the inclination of the first arm 109 and the second arm 110 and the driving amount of the first, second, and third rotating arms. Can be calculated geometrically from Further, it is possible to calculate the driving amounts of the first, second, and third motors from the spatial position coordinates of the output member 103 by calculation of inverse kinematics.

[Change orientation of output member]
Next, a configuration for changing the direction of the output member 103 (the rotation angle of the end effector 104) will be described with reference to FIGS. This is to control the rotation angle around the first shaft 105 while maintaining the inclination (substantially vertical) of the end effector 104 attached to the output member 103.

  5, 8, and 9, the fourth motor 113 as the fourth actuator is an example of a rotary actuator. The fourth motor 113 is disposed such that the rotation shaft is positioned coaxially with the rotation shaft of the second motor 108. In the present embodiment, the fourth motor 113 is disposed below the second motor 108 in the vertical direction.

  A pulley 114 is pivotally fixed to the rotation shaft of the fourth motor 113. On the other hand, a pulley 115 is rotatably supported on a second link shaft 108b provided at the tip of a second rotating arm 108a that is supported on the rotating shaft of the second motor 108. The pulleys 114 and 115 have the same number of teeth and the same diameter, and a timing belt 116 is stretched between the two pulleys. A link plate 117 is coupled to the pulley 115 so as to rotate together with the pulley 115.

  Further, the output member 103 is provided with a rotating portion 103a (FIG. 10) having the first shaft 105 as a rotation axis. This rotation axis is a rotation axis parallel to the pressing direction in which the work gripped by the end effector 104 is pressed against the counterpart member. Between the rotation part 103a and the 4th motor 113, the 4th arm 119 as a transmission member which rotates the rotation part 103a by the drive of a 4th motor is arrange | positioned. The configuration from the rotation unit 103a to the fourth motor 113 corresponds to a rotation drive unit that rotates the end effector 104 about the rotation axis. Further, a link plate 118 is connected to the rotating portion 103a via a speed increasing rotation mechanism 300 described later.

  The fourth arm 119 includes at least one fourth link 119a disposed in parallel with the second link 110a. In the present embodiment, the fourth arm 119 is configured by one fourth link 119a. Such a fourth arm 119 rotates at least about an axis parallel to the first axis 105 with respect to the link plate 118 whose one end is connected to the rotation unit 103a, and on the first axis 105. They are connected in a state having two degrees of freedom capable of rotating around an axis orthogonal to the parallel axis and the direction in which the fourth arm 119 is disposed. Further, the other end is connected at a position off the second link shaft of the link plate 117 as a drive rotating portion that rotates about the second link shaft 108b.

  Specifically, one fourth link 119a has one end connected to the tip of the link plate 118 with a two-degree-of-freedom joint 119b and the other end connected to the tip of the link plate 117 with a two-degree-of-freedom joint 119c. Connected. Here, the joint portion 119c rotates about an axis parallel to the second link shaft 108b, and an axis orthogonal to the axis parallel to the second link shaft 108b and the arrangement direction of the fourth link 119a. The rotation around the center is possible.

  The joint portions 119b and 119c are the same as those having the structure shown in FIG. 7 described above, and may have at least two degrees of freedom. Further, as the joint portions 119b and 119c, a joint having three degrees of freedom such as a ball joint and a rod end joint may be used.

  In addition, the distance between the position (joint portion 119b) to which the one end of the fourth link 119a is connected and the first shaft 105, and the drive rotation portion side to which the other end of the fourth link 119a is connected. The distance between the position (joint portion 119c) and the second link shaft 108b is the same. In the present embodiment, the link plate 117 and the link plate 118 having the same shape and the same size are used, and the lengths of the respective rotation centers and the joint portions are made to coincide with each other. The lengths of the second link 110a and the fourth link 119a are the same. The fourth link 119a and the second link 110a constitute a parallel link mechanism. As a result, the fourth arm 119 is disposed so as to maintain the parallel state with the second arm 110 regardless of the position of the output member 103 and the rotating state of the rotating portion 103a.

  Next, an operation in the case of rotating the rotation unit 103a by driving the fourth motor 113 will be described with reference to FIG. In FIG. 9A, when the fourth motor 113 is rotated in the arrow α direction, the link plate 117 is rotated in the arrow β direction by the pulleys 114 and 115 and the timing belt 116. The link plate 118 is rotated in the arrow γ direction by the fourth arm 119 connected to the link plate 117. Since the fourth link 119a constituting the fourth arm 119 and the second link 110a constituting the second arm 110 constitute a parallel link mechanism, the rotation angle of the link plate 117 as shown in FIG. The rotation angles of the link plates 118 are the same.

  Further, as shown in FIG. 9C, since the number of teeth and the diameter of the pulley 114 and the pulley 115 are the same, the second motor 108 is driven and the second rotating arm 108a is rotated to any position. If the fourth motor 113 is held without being driven, the angle of the link plate 117 is kept constant. Therefore, the angle of the link plate 118 is also kept constant by the parallel link mechanism of the second arm 110 and the fourth arm 119.

[Speed-up rotation mechanism]
Next, as a speed increasing means that is arranged on the first axis (on the rotation axis of the end effector 104) and accelerates the rotation of the fourth arm 119 (drive of the rotation drive unit) and transmits it to the rotation unit 103a. The speed increasing rotation mechanism 300 will be described with reference to FIGS. First, the rotation of the end effector 104 can be controlled by directly or indirectly connecting the rotation shaft of the link plate 118 to the first shaft 105 that supports the end effector 104. Moreover, the rotation amount of the end effector 104 is uniquely determined by the driving amount of the fourth motor 113 and is not affected by the driving amounts of the first to third motors.

  However, in the rotation control of the end effector 104 by the parallel link mechanism, since the fourth arm 119 interferes with the end effector 104 when the link plate 118 rotates, the rotation angle is limited and a sufficient amount of rotation is obtained. It is difficult.

  For this reason, in this embodiment, the rotational speed increasing mechanism 300 is provided in the rotation part 103a connected to the link plate 118 so that the rotation angle of the end effector 104 is increased. The speed increasing rotation mechanism 300 is disposed on the rotation axis of the rotation unit 103a, that is, coaxially with the first shaft 105, and increases the rotation of the fourth arm 119 as a transmission member to the rotation unit 103a. introduce. The speed increasing rotation mechanism 300 of this embodiment is constituted by a planetary gear mechanism.

  That is, as shown in FIG. 12, the speed increasing rotation mechanism 300 includes a sun gear 301, an internal gear 302, a plurality of planetary gears 303, and a carrier 304. The sun gear 301 and the internal gear 302 are respectively disposed on the rotation shaft of the rotation unit 103a. The plurality of planetary gears 303 is disposed between the sun gear 301 and the internal gear 302 and meshes with the sun gear 301 and the internal gear 302. The carrier 304 rotatably holds a plurality of planetary gears 303. The sun gear 301 is connected to the rotating portion 103 a, and either the internal gear 302 or the carrier 304 is connected to the fourth arm 119, and the other is the first shaft (output shaft) 105 of the output member 103. Fixed to.

  The speed increasing rotation mechanism 300 may be configured such that the internal gear 302 is connected to the rotating portion 103a, the carrier 304 is connected to the fourth arm 119, and the sun gear 301 is fixed to the output member. Regardless of the structure, the input from the fourth arm 119 is accelerated by the planetary gear mechanism and output to the rotating unit 103a. In the present embodiment, the sun gear 301 is connected to the rotating unit 103 a, the carrier 304 is connected to the fourth arm 119, and the internal gear 302 is fixed to the first shaft (output shaft) 105. This will be specifically described with reference to FIGS.

  The link plate 118 connected to the fourth arm 119 via the joint portion 119b is integrally formed with a carrier 304, and the carrier 304 is fixed with three gear shafts 305 equally arranged on the same circumference. ing. Each gear shaft 305 is rotatably supported by the same planetary gear 303.

  A ring-shaped internal gear 302 that meshes with the planetary gears 303 is fixed to the case 306 on the outside of the plurality of planetary gears 303, and the case 306 is fixed to the first shaft 105 of the output member 103 with a set screw 307.

  On the other hand, a sun gear 301 that meshes with the planetary gears 303 is provided inside the plurality of planetary gears 303. As shown in FIG. 11, the sun gear 301 is supported by a bearing 308a and a bearing 308b coaxially with the first shaft 105 so as to be rotatable with respect to the first shaft 105. Further, the E-ring 309 provided at the lower end portion of the first shaft 105 prevents the sun gear 301 from coming off the first shaft 105 in the axial direction via the bearing 308b.

  A rotating part 103a is integrally formed at the lower end of the sun gear 301, and a mounting part 310 for the end effector 104 is formed in the rotating part 103a. The mounting portion 310 has a fitting portion 310a for accurately positioning the end effector 104, a notch groove 310b, and a screw fixing tap hole 310c.

  The link plate 118 to which the fourth arm 119 is connected is fixed to the holder 311 arranged coaxially with the internal gear 302 and the sun gear 301 with screws 312. The holder 311 is rotatably supported on the sleeve portion 301a of the sun gear 301 by two bearings 314 arranged at a predetermined interval by a spacer 313.

In such a configuration, when the link plate 118 rotates, the three planetary gears 303 rotate while revolving and rotate the sun gear 301. In the present embodiment, the number of teeth Za of the sun gear 301 is 18, the number of teeth Zb of the planetary gear 303 is Zb = 18, the number of teeth of the internal gear 302 is Zc = 54, the internal gear 302 is fixed, and the planetary gear carrier 304 is input. The sun gear 301 is used as an output. For this reason, the speed increasing ratio of the planetary gear mechanism is
(Za + Zc) / Za = (18 + 54) / 18 = 4
It becomes.

  As a result, the rotation angle of the link plate 118 by the fourth arm 119 is increased four times, and the end effector 104 rotates. Therefore, the end effector 104 can obtain one or more rotations of the end effector 104 without the fourth arm 119 interfering with the end effector 104 regardless of the position of the end effector 104. Moreover, since the rotation amount and rotation speed of the end effector 104 are always proportional to the rotation drive amount and drive speed of the fourth motor 113, precise rotation control is possible.

As described above, there is an advantage that the highest speed increase ratio can be obtained by fixing the internal gear 302, inputting the carrier 304, and outputting the sun gear 301. However, the carrier 304 may be fixed, the internal gear 302 may be input, and the sun gear 301 may be output for convenience of component arrangement and configuration. The speed increase ratio of the planetary gear mechanism in this case is
-Zc / Za = -54 / 18 = -3
Thus, the rotation angle of the link plate 118 by the fourth arm 119 is increased three times, and the end effector 104 rotates. However, the rotation direction of the output with respect to the input is reversed.

Alternatively, the sun gear 301 may be fixed, the carrier 304 may be input, and the internal gear 302 may be output. The speed increase ratio of the planetary gear mechanism in this case is
(Za + Zc) / Zc = (18 + 54) /54=1.33
Thus, the rotation angle of the link plate 118 by the fourth arm 119 is increased by about 1.3 times, and the end effector 104 rotates. In this case, since the speed increasing ratio is small, it is preferable to use it for a configuration in which the rotational angle of the end effector 104 is desired to be slightly increased.

  In the above description, the fourth arm 119 is provided so as to be always parallel to the second arm 110, but may be provided so as to be always parallel to the first arm 109. In that case, the rotation shaft of the fourth motor 113 can be arranged at a position coaxial with the rotation shaft of the first motor 107, and a similar rotation transmission mechanism using a pulley and a timing belt can be employed.

  In the above description, the rotation angle around the axis of the first axis 105 that supports the end effector 104 is controlled. However, the rotation around the axis of the second axis 106 that forms a predetermined angle with the first axis 105. It is good also as a structure which controls an angle. In that case, the fourth arm 119 is provided so as to be always parallel to the third arm 112, the rotation shaft of the fourth motor 113 is disposed at a position coaxial with the rotation shaft of the third motor 111, and a similar pulley is provided. It is possible to adopt a rotation transmission mechanism using a timing belt.

  Furthermore, in the above description, the transmission member that transmits the drive of the fourth motor 113 to the rotation unit 103a is the fourth arm 119, but the configuration of the transmission member is not limited thereto. For example, the rotation member fixed on the rotation shaft of the fourth motor 113 and the rotation unit 103a may be connected by a wire to transmit the rotation.

[Stepping motor]
In the present embodiment, the first motor 107 (first actuator), the second motor 108 (second actuator), the third motor 111 (third actuator), and the fourth motor 113 (fourth actuator) described above are used. It is a stepping motor. That is, all actuators that drive the output member 103 are stepping motors. In the stepping motor of this embodiment, the rotor is configured by a permanent magnet, and the stator is configured by a winding. And a rotor is rotated by applying an electric current to a winding with a predetermined pulse.

  Such a stepping motor of this embodiment will be described with reference to FIGS. In FIG. 13, reference numeral 1001 denotes a stepping motor for driving the output member 103 of the parallel link robot, which corresponds to the first motor 107, the second motor 108, the third motor 111, and the fourth motor 113. A control device 1002 outputs an operation command to the stepping motor 1001 and is connected to the stepping motor 1001 via the motor driver 1003. The motor driver 1003 includes a power transistor 1005 for driving the stepping motor 1001 and a signal output port 1004 that receives a command from the control device 1002 and outputs a pulse signal at a predetermined timing.

  When the pulse signals p1 to p4 shown in FIG. 14 are output from the signal output port 1004 in response to a command from the control device 1002, the stepping motor 1001 sets the step angle by the power transistor 1005 that has received the pulse signals p1 to p4. It is driven to rotate as a unit. The stepping motor 1001 driven in this way does not hunting when the rotation amount is lowered, and can maintain the position with a high holding torque when stopped.

  More specific description will be given with reference to FIGS. 5 and 6. The parallel link robot 100 only needs to control the rotation amounts of the first motor 107, the second motor 108, and the third motor 111 in order to translate the output member 103, and the rotation amount of the fourth motor 113 is as follows. It does not affect the determination of the position of the output member 103. That is, the first, second, and third motors 107, 108, and 111 are actuators for determining the position, and the fourth motor 113 is an actuator for changing the posture, and the translational motion and the rotational motion of the output member do not interfere with each other. .

  For example, in the operation of moving the position of the output member 103 from the current position Xn to the target position Xn + 1, if the first, second, and third motors 107, 108, and 111 are driven by a necessary amount, the first, second, and second The three arms 109, 110, and 112 move the position of the output member 103 in cooperation. The operation cannot be performed unless the driving amounts of the first, second, and third motors 107, 108, and 111 become zero at the same time as the position of the output member 103 reaches the target position Xn + 1. Accordingly, by using the first motor 107, the second motor 108, and the third motor 111 as stepping motors, the hunting is not performed when the rotation amount is lowered, and the driving amounts of the first, second, and third motors 107, 108, and 111 are increased. Without being affected, the position of the output member can be settled on demand. Therefore, in the parallel link robot, there is an effect of improving the reliability of precise work including a minute operation that changes the posture while holding the position of the output member.

  Further, the parallel link robot 100 may control the rotation amount of the fourth motor 113 in order to rotate the output member 103, and the rotation amounts of the first motor 107, the second motor 108, and the third motor 111 are output. It does not affect the posture change of the member 103. For example, in the operation of changing the posture of the output member 103 from the current posture Rn to the target posture Rn + 1, when the fourth motor 113 is driven by a necessary amount, the fourth arm 119 changes the posture of the output member 103. If the attitude of the output member 103 reaches the target attitude Rn + 1 and at the same time the driving amount of the fourth motor 113 is not zero, the work cannot be performed. Therefore, by making the fourth motor 113 a stepping motor, the hunting is not performed when the rotation amount is lowered, and the posture of the output member 103 is stabilized according to the request without being influenced by the driving amount of the fourth motor 113. be able to. Therefore, in the parallel link robot, there is an effect of improving the reliability of precise work including a minute operation of moving the position while maintaining the posture of the output member.

  As described above, in this embodiment, the first motor 107, the second motor 108, the third motor 111, and the fourth motor 113 that drive the output member 103 are stepping motors. The stepping motor does not hunt when the rotation amount is lowered, and can maintain the position with a high holding torque when stopped. For this reason, the position and posture of the output member 103 can be settled as required without being affected by the driving amount of the motor, and the minute operation and posture for changing the posture while holding the position can be held. Thus, it is possible to provide a parallel link robot including a minute operation for moving the position while improving the reliability of precise work.

  In the above description, the control system of the parallel link robot has been described as open loop control. However, the control system may be realized by appropriately combining semi-closed or closed loop control. The pulse signal is not limited to the two-phase excitation method. In the above description, the actuator for changing the posture is only the fourth actuator, but a larger number of actuators may be provided in parallel with the fourth actuator so that the output member can perform a more complicated posture change.

  In the case of the present embodiment, the third motor 111 that moves the output member 103 in the vertical direction is a stepping motor whose rotor is constituted by a permanent magnet. For this reason, even if the power supply to the third motor 111 is interrupted, the output member 103 can be prevented from dropping by cogging. That is, even when the power supply to the third motor 111 is interrupted, cogging occurs due to the magnetic force acting between the permanent magnets constituting the rotor and the stator, and at least the speed at which the output member 103 falls is slowed down. Or it can be prevented from falling. As a result, it is possible to prevent the output member 103 from dropping suddenly without providing an electromagnetic brake, and it is possible to prevent the work held by the output member 103 from colliding with the stage or the like and being damaged. In this embodiment, it is not necessary to provide an electromagnetic brake as described above, and since an inexpensive stepping motor is used, the cost of the parallel link robot can be reduced.

  In the present embodiment, all the motors that drive the output member 103 are stepping motors, but at least the third motor 111 is stepped in order to suppress the drop of the output member 103 when the energization is interrupted. Any motor can be used. Further, when the arrangement or the like of each motor is changed and the output member is moved in the vertical direction by a plurality of motors, these plurality of motors are set as stepping motors. In short, a stepping motor is a motor that can support the vertical movement of the output member by stopping driving.

  In the case of this embodiment configured as described above, the posture and orientation of the output member 103 can be kept constant regardless of the movement position of the output member 103 as described above. For example, Japanese Patent No. 4901557 discloses a structure in which links constituting three arms driven by a drive mechanism (actuator) are connected to a manipulator (output member) using joint devices each having three degrees of freedom. Have been described. In the case of this structure, since the manipulator is not constrained by rotation around the output shaft, the direction of the end effector attached to the manipulator changes depending on the movement position. That is, since the three arms are connected to the manipulator by the joint device having three degrees of freedom, the rotation of the manipulator is not restricted. For this reason, when the manipulator is moved using three arms, the rotation angle (direction) of the manipulator changes before and after the movement. If the direction of the manipulator changes depending on the movement position in this way, it is difficult to carry or position the workpiece as a robot operation.

  On the other hand, in the present embodiment, by configuring as described above, the posture and orientation of the output member 103 can be kept constant regardless of the movement position of the output member 103. Then, by performing positioning control of the output member 103 with the above-described configuration, the end effector 104 can be moved while maintaining the posture (tilt) and orientation of the end effector 104 attached to the output member 103. Further, when the end effector 104 is rotated at any time during the search operation for the part into which the workpiece is inserted, the direction of the end effector 104 can be accurately changed to, for example, a preset program direction.

  In addition, since the posture and orientation of the output member 103 are held by the first arm 109 and the third arm 110, the second arm 110 only needs to include at least one second link 110a. Since the second arm 110 is composed of one second link 110a, the apparatus can be reduced in size and cost.

  Furthermore, in the case of this embodiment, the output member 103 is provided with a rotating portion 103a, and the rotation of the end effector 104 is controlled by rotating the rotating portion 103a. For this reason, it is not necessary to rotate the first shaft 105 to which the third arm 112 is connected, and the connecting portion between the third arm 112 and the first shaft 105 can be configured simply. As a result, the direction of the end effector 104 can be changed with a simple configuration without greatly restricting the movable range of the output member 103, and the cost of the apparatus can be reduced. Further, the use of the speed increasing rotation mechanism 300 can reduce the possibility that the workpiece 1 is not aligned with the insertion position.

  For example, Patent Document 1 described above also describes a structure in which a link constituting one arm of three arms is connected to a manipulator by a universal / cardan joint. Thus, in the case of a structure in which a link constituting one arm is connected to a manipulator by a universal / cardan joint, the rotation of the manipulator and the end effector attached thereto can be controlled by rotating the arm.

  However, when the arm is connected to the manipulator by the universal / cardan joint in this way, the universal / cardan joint is used to control the rotation of the manipulator. For this reason, the drive mechanism of this arm becomes very complicated and causes an increase in cost. In addition, since the universal / cardan joint has a limitation on the operating angle, the position range (movable range) of the manipulator that can be controlled is greatly limited.

  On the other hand, in the case of the present embodiment, the rotation of the end effector 104 is controlled without using a universal / cardan joint at the connection between the third arm 112 and the first shaft 105 of the output member 103. For this reason, it is possible to control the rotation of the rotating portion 103a of the output member 103 with a simple configuration, and to change the orientation of the end effector.

<Third Embodiment>
A third embodiment of the present invention will be described with reference to FIGS. Note that the difference from the third embodiment described above is that the two first links 109a of the first arm 109 are arranged in parallel with the first shaft 105 of the output member 103 (third shaft portion). ) 400 and the second arm 110 are two second links 110a. For this reason, the same code | symbol is attached | subjected to the component which is common in 3rd Embodiment, the description is abbreviate | omitted or simplified, and it demonstrates below centering on a different part from 3rd Embodiment.

  As shown in FIGS. 15 and 16, the connecting member 401 is fixed to the first shaft 105 with a knock pin or the like. Further, the connecting member 401 is detached from the first shaft and parallel to the first shaft 105. The third shaft 400 is fixed with a knock pin or the like. Thus, the first shaft 105 and the third shaft 400 are always kept parallel with a predetermined interval (offset).

  The first arm 109 is composed of two first links 109a forming a parallel link mechanism, and one end is connected to the third shaft 400 by a joint portion 109b having two degrees of freedom, and the other end is connected to the first link shaft 107b by two. They are connected by a joint portion 109c having a degree of freedom.

  The second arm 110 is composed of two second links 110a of the same length forming a parallel link mechanism, one end is connected to the first shaft 105 by a joint part 110b with two degrees of freedom, and the other end is a second link. The shaft 108b is connected to the joint portion 110c having two degrees of freedom. In addition, also about such a 2nd arm 110, it is good also considering the joint parts 110b and 110c as three degrees of freedom. In this case, as shown in FIG. 7B described above, in order to prevent the parallel link mechanism from being twisted, bridge members 201 and 202 are disposed as restricting members that restrict the rotation around the axis of the link. .

  By the parallel link of the first arm 109 and the second arm 110, the first shaft 105 that supports the end effector 104 is always kept parallel to the first link shaft 107b and the second link shaft 108b. As a result, the posture (tilt) of the end effector 104 is kept constant (substantially vertical) regardless of the position of the first rotating arm 107a and the second rotating arm 108a. In the case of the present embodiment, it is possible to keep the posture (tilt) constant (substantially vertical) more stably as compared with the configuration of the first embodiment described above.

  Due to the two parallel link mechanisms formed by the first arm 109 and the second arm 110 and the parallel link mechanism formed by the third arm 112, the end effector 104 attached to the output unit has a certain posture (tilt) and orientation. Supported to keep both.

  In the case of this embodiment, as compared with the first embodiment described above, the fixed position of the first motor 107 with respect to the base member 100A is set to the inter-axis distance (offset value) between the first shaft 105 and the third shaft 400. ) Are offset by the same distance in the same direction. By offsetting the position of the first motor 107 in this way, the length of the first rotating arm 107a and the first arm 109 and the rotation control amount of the first motor 107 are not changed, and the configuration of the first embodiment described above. The movement control of the end effector 104 can be performed under the same conditions as in FIG.

  Further, the rotation angle control mechanism around the first shaft 105 that is the mounting center axis of the end effector 104 is the same as that in the first embodiment, as shown in FIGS. 17 and 18. Also in the present embodiment, the fourth arm 119 is provided so as to be always parallel to the second arm 110, and the rotation amount of the end effector 104 depends on the drive amount of the fourth motor 113 as in the first embodiment. It is uniquely determined and is not affected by the driving amounts of the first to third motors. Further, also in the present embodiment, as shown in FIGS. 19 and 20, a speed increasing rotation mechanism 300 similar to that of the first embodiment is provided.

  In this embodiment configured as described above, the position of the first arm 109 connected to the output member 103 is offset with respect to the first shaft 105 to which the second arm 110 is connected. The length of 105 can be shortened. That is, unlike the first embodiment, since it is not necessary to connect the first arm 109 and the second arm 110 to the first shaft 105, the first shaft 105 can be shortened accordingly. As a result, the output member 103 can be made compact.

  In the case of this embodiment as well, the second arm 110 may be configured by a single first link 110a as in the first embodiment. Further, as a configuration in which the first arm 109 is offset with respect to the output member 103, in addition to providing the third shaft 400 described above, for example, a projection is provided on the first shaft 105 and the first arm 109 is provided on the projection. You may make it connect. In this case, the first arm 109 is connected to the protrusion on a virtual axis that is parallel to the first axis 105 and corresponds to the third axis 400 described above. Other configurations and operations are the same as those of the above-described third embodiment.

<Other embodiments>
In the above description, each of the first, second, third, and fourth actuators is an electric rotary actuator (motor). However, for example, a mechanism that converts a driving force in a linear direction is added, and linear ( (Linear motion) Actuator may be used.

1 work 2 mating member 3 insertion hole (insertion position)
4 Search range (predetermined range)
10 Work Inserting Device 11 Hand (gripping part)
12 Arm (moving part)
13 Spring part (pressing part, connecting part)
14 Control device (control unit)
15 Biasing spring (Biasing means)
100 Parallel link robot 103 Output member (manipulator)
104 End effector (grip)
109 First arm (moving part)
110 Second arm (moving part)
112 Third arm (moving part)
113 4th motor (rotation drive part)
103a Rotation part (rotation drive part)
300 Speed increasing rotation mechanism (speed increasing means)

Claims (7)

A gripping part capable of gripping a workpiece;
A pressing portion that presses the workpiece gripped by the gripping portion toward the counterpart member;
A moving unit for moving the gripping unit;
A control unit that moves the moving unit within a predetermined range on a virtual plane that includes the insertion position of the workpiece and is orthogonal to the pressing direction of the pressing unit while pressing the workpiece held by the holding unit against the counterpart member. When,
When the work gripped by the gripping part does not match the insertion position, the gripping part is moved following the moving part, and when the work gripped by the gripping part matches the insertion position, A connecting portion that connects the gripping portion and the moving portion so that the moving portion can move relative to the gripping portion within the predetermined range.
A workpiece insertion device characterized by that. The connection part is an elastic member provided between the grip part and the moving part, and also serves as the pressing part.
The work insertion device according to claim 1, wherein The control unit releases the gripping of the workpiece by the gripping unit after causing the moving unit to perform a predetermined operation.
The workpiece insertion device according to claim 1, wherein the workpiece insertion device is characterized. The gripping portion has a biasing means that biases the workpiece released from gripping toward the counterpart member.
The workpiece insertion device according to any one of claims 1 to 3, wherein the workpiece insertion device is characterized in that: A rotation drive unit that rotates the gripping unit about a rotation axis parallel to the pressing direction;
The workpiece insertion device according to any one of claims 1 to 4, wherein the workpiece insertion device is characterized in that: A speed increasing means arranged on the rotating shaft of the gripping portion and speeding up the driving of the rotation driving portion and transmitting the speed to the gripping portion;
The work insertion device according to claim 5, wherein   A parallel link robot comprising the workpiece insertion device according to any one of claims 1 to 6 and inserting a workpiece.

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