JP2008246596A - Transfer robot and 3-degree-of-freedom parallel link mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer robot flexibly handling the transfer of articles produced by multi-product production in low volume or in variable volume, which is easily handled upon occurrence of trouble and relatively easily controllable with respect to its position, attitude and power during operation without causing a jackknife phenomenon even when an article transfer tool (hand-pushed cart) is moved by pushing operation, and also to provide a 3-degree-of-freedom parallel link mechanism suitable for the transfer robot. <P>SOLUTION: This transfer robot 10 is provided with: a robot body 12 performing movement; the parallel link mechanism 20 coupled to the robot body 12; and a coupling mechanism 40 performing coupling and separation between the parallel link mechanism 20 and the article transfer tool 1. The parallel link mechanism 20 is provided with a first link 21, a second link 22, and a third link 23, and according to the driving conditions of each link, a relative position and attitude on the horizontal plane of an output member 24 relative to the robot body 12 are set in this 3-degree-of-freedom parallel link mechanism. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transfer robot that moves an article transfer tool and a three-degree-of-freedom parallel link mechanism.

  Conventionally, in factories and the like, by using a cart called AGV (Automated Guided Vehicle) that automatically runs unattended by computer control, the transportation and supply of parts, semi-finished products, finished products, etc. between various processes can be automated. Yes. The AGV usually has a transport base at the top, and transports the article by moving the article to be transported on the transport base.

In recent years, the tendency of high-mix low-volume / variable-volume production has progressed in factories and the like, and the quantity and type of goods to be transported in one line greatly fluctuate within one day. The use of AGV in such a field has the following drawbacks.
・ Because it is not possible to change the transfer platform and device size according to the amount of material, even when a small amount of transfer occurs, the device that takes into account the maximum time is used as it is, and both space and energy are inefficient.
-Since the size of articles that can be loaded is limited to the size of the conveyance table or less, there is a situation in which conveyance is not possible due to product type changes.
In order to match the quantity, it is necessary to have multiple types of AGVs with different sizes, and even in this case, the efficiency is similarly poor from the point of view of operating rate.

In addition, with respect to frequent line changes resulting from shortening of product cycles in recent years, AGV has the following disadvantages because it is transported by a method different from humans.
・ Since the dedicated space is taken, when the equipment stops due to line change or trouble, the place becomes dead space.
・ Because it is integrated with the transport platform, it is difficult to replace it manually as needed.

  Since there are many inefficiencies as described above, in many of the lines that handle various varieties / variables, transportation / supply of parts, semi-finished products, and finished products between processes is performed manually.

On the other hand, there is a conventional technique in which the movement / loading function is separated from the AGV described above.
One of them is a towing system in which a mobile robot pulls and moves a carriage like a trailer. Normally, a mobile robot is a nonholonomic type that cannot move sideways. Therefore, in order to stop the carriage accurately at the target location, it is effective to move the cart by pushing near the target location. is there. However, when the pushing operation is performed by the traction method, a state called a jack knife phenomenon occurs where the towed vehicle (cart) enters the inside of the towed vehicle (mobile robot) and the position of the towed vehicle cannot be controlled. There are examples of research to control these, but control is difficult and there are almost no practical examples.

  As another example, Patent Document 1 below proposes a technique for moving a carriage by a humanoid robot having two arms and two legs. If this humanoid robot is used, it is possible to move the cart without causing a jackknife phenomenon even when a pushing operation is performed on the cart. However, in determining the relative position and posture (6 degrees of freedom) between the robot and the carriage, the two arms (usually each 6 degrees of freedom = 12 degrees of freedom) are redundant, and the position, posture, The method for determining the arm operation from the force or the like becomes complicated.

JP 2006-175567 A

  The present invention has been made in view of the above-mentioned problems, can flexibly cope with the conveyance of articles produced in a variety of small quantities and variable quantities, is easy to deal with when trouble occurs, and is conveyed by pushing operation. It is an object of the present invention to provide a transfer robot that does not cause a jackknife phenomenon even when a tool (hand carriage, etc.) is moved, and that is relatively easy to control the position, posture, and force during operation. Another object of the present invention is to provide a three-degree-of-freedom parallel link mechanism suitable for the above-described transfer robot.

In order to solve the above problems, the transport robot and the three-degree-of-freedom parallel link mechanism of the present invention employ the following means.
(1) The present invention is a transfer robot that moves an article transfer tool that moves by receiving an external force by placing an article, and a movable robot body and a base end portion are connected to the mobile robot and driven independently. A plurality of possible links and an output member connected to the tips of the plurality of links, and a relative position of the output member with respect to the robot body in space or on a plane depending on a driving state of the links And a parallel link mechanism whose posture is determined, and an output member of the parallel link mechanism, and the parallel link mechanism and the article transporter so that a relative position and posture between the output member and the article transporter can be fixed. And a connecting mechanism for connecting and disconnecting to and from.

According to the above configuration, the article is conveyed by moving the robot main body while controlling the relative position and posture of the article carrier with the parallel link mechanism coupled to the coupling mechanism by the coupling mechanism. The tool can be moved. Thus, unlike the conventional AGV, the transfer function and the article loading function are separated, not the transfer by the dedicated transfer stand integrated with the robot. Common items (handcarts, carts, etc.) can be used. Therefore, unlike the conventional AGV, it can be easily changed to an article conveying tool of a suitable size according to the quantity / variety, and there is no need to prepare a plurality of types of conveying robots according to the quantity, Both space and energy are efficient.
In addition, since it is not integrated with the transfer platform, it can be made smaller and lighter than conventional AGVs, so even if an abnormal situation occurs in the transfer robot and it becomes inoperable, Can be removed easily. In addition, since the article conveying tool can be used in common with a person, the person can take over the conveying work in place of the conveying robot that has become inoperable.
In addition, the relative position and posture of the parallel link mechanism and the article transporter are fixed by the coupling mechanism, and the article transporter is moved while controlling the relative position and posture by the parallel link mechanism. Even in the case of moving the jack jack phenomenon does not occur. Therefore, even in a non-holonomic type robot that cannot move to the side, the article transport tool can be accurately stopped at the target location by moving the article transport tool by a pushing operation in the vicinity of the target travel location.
In addition, since a parallel link mechanism is employed as a mechanism for controlling the relative position and posture of the article transporter with respect to the robot body, three freedoms may be used to control the relative position and posture on the plane, and relative to space. Even if the position and posture are controlled, 6 degrees of freedom is sufficient. Compared with two arms (12 degrees of freedom) that move in almost the same way as a human arm, the position, posture, and force required for the movement Control becomes easy.

(2) Further, in the transfer robot, the parallel link mechanism includes a first link, a second link, and a third link connected in parallel between the robot body and the output member. A three-degree-of-freedom parallel link mechanism in which a relative position and posture of the output member with respect to the robot main body on a horizontal plane is determined by driving states of the link, the second link, and the third link, and the first link and the third link Each of the links has one end connected to the robot body so as to be rotatable around a vertical axis, and the other end is connected to the output member so as to be rotatable around a vertical axis, and is driven to drive between the both ends. The second link has one end connected to the robot body so as to be rotatable about a reference axis centered in the vertical direction, and the other end vertically connected to the output member. It is connected so as to be rotatable around a center, and when driven, the direction about the reference axis with respect to the robot body changes, and is driven by the driving of the first link and the third link. Thus, the distance between both ends changes.

  According to the above configuration, by driving the first link, the second link, and the third link independently, the position and posture of the output member can be set to three degrees of freedom in the plane (traveling direction x on the horizontal plane, on the horizontal plane). Therefore, the relative position and posture of the article transporter on the horizontal plane with respect to the robot body can be controlled by the y-direction perpendicular to the x-direction and the rotation angle θz around the z-axis perpendicular to the horizontal plane.

(3) Further, in the transfer robot described above, each of the first link, the second link, and the third link includes two arms having a midpoint between the both ends as a connection point. The connecting point is a bending / extending motion with the joint as a joint, and the distance between both ends is changed by the bending / extending motion.

  According to the above configuration, since each link has a joint, a range in which the distance between both ends changes (extension / contraction range) can be easily widened, and the movable range of the parallel link mechanism can be set wide. Therefore, the control range of the relative position and posture of the article transporter with respect to the mobile robot can be widened.

(4) In the transfer robot described above, the first link, the second link, and the third link are positioned so that the second link is positioned at an intermediate position in the separation direction of the first link and the third link. The first link and the third link are connected to each other so that two arms are rotatable about a vertical axis, and the two arms of the second link are connected to each other. It is connected so as to be rotatable around a horizontal axis.

  According to the above configuration, since the first link and the third link that are actively expanded and contracted are arranged so as to sandwich the second link, the load is not biased to either the first link or the second link. . Further, when the second link is bent, the joint portion is bent so as to protrude upward or downward, and when the first link and the third link are bent, the joint portion moves in the horizontal direction and either Since they are bent so as to be convex in this direction, they hardly interfere with each other mechanically. It should be noted that when the first link and the second link are bent so that the distance between the joints becomes a convex shape, even if the arrangement interval between the first link and the third link is narrow, the mutual link Mechanical interference can be prevented.

(5) In the transfer robot, the first link includes a first drive motor fixed at a position of a connection point with the robot body, and rotational movement of the first drive motor. A power conversion mechanism for a first link that converts to a bending and stretching motion, and the second link is fixed at a position of a connection point with the robot body and is centered on the reference axis of the second link with respect to the robot body. A second drive motor that changes the orientation of the third drive motor, the third link being fixed at a position of a connection point with the robot body, and a rotational motion of the third drive motor in relation to the third drive motor. A power conversion mechanism for a third link that converts to a bending and stretching motion of three links.

  According to the above configuration, since each drive motor that drives each link is installed at the position of the connection point between each link and the robot body, the moment acting on each link can be reduced. Further, by installing each drive motor at the above position, the center of gravity of the entire transfer robot can be easily set on the robot body side, so that it can be moved and stopped stably.

(6) Further, in the transfer robot, the first link power conversion mechanism and the third link power conversion mechanism are configured by a parallel link mechanism.

  According to the said structure, since each power conversion mechanism is comprised with a parallel link mechanism, the rotational motion of a drive motor can be reliably converted into the bending motion of a link with a simple structure.

(7) Further, according to the present invention, a base member, a first link, a second link, and a third link that have base ends connected to the base member and can be independently driven, the first link, and the second link A link and an output member connected to the tip of the third link, and relative to the base member on a predetermined plane with respect to the base member according to the driving state of the first link, the second link, and the third link. A three-degree-of-freedom parallel link mechanism with a fixed position and orientation, wherein each of the first link and the third link is rotatable about an axis perpendicular to the predetermined plane on the base member. The second link is connected, the other end is connected to the output member so as to be rotatable about an axis perpendicular to the predetermined plane, and the distance between both ends is changed by driving. Is one end The base member is connected to be rotatable about a reference axis perpendicular to the predetermined plane, and the other end is connected to the output member to be rotatable about an axis perpendicular to the predetermined plane. In addition, when driven, the direction around the reference axis with respect to the base member is changed, and the distance between both ends is changed by driving the first link and the third link. It is characterized by being.

According to the above configuration, the first link, the second link, and the third link are independently driven, so that the position and posture of the output member can be set to three degrees of freedom (the traveling direction x on the predetermined plane, the predetermined plane). In the y direction perpendicular to the x direction and the rotation angle θz around the z axis perpendicular to the predetermined plane. Therefore, it is suitable as a parallel link mechanism for the transfer robot.
Further, by mounting various tools (article gripping tool, processing tool, etc.) according to the purpose on the output member, the output member can be applied to a transport mechanism of an article transport device, a positioning mechanism of a processing device, and the like.

(8) Further, in the above three-degree-of-freedom parallel link mechanism, each of the first link, the second link, and the third link is composed of two arms having a midpoint between the both ends as a connection point, A bending / extending motion is performed with the connecting point of the two arms as a joint, and the distance between both ends is changed by the bending / extending motion.

  According to the above configuration, since each link has a joint, a range in which the distance between both ends changes (extension / contraction range) can be easily widened, and the movable range of the parallel link mechanism can be set wide.

(9) In the three-degree-of-freedom parallel link mechanism, the first link, the second link, and the third link are located at an intermediate position in the separation direction of the first link and the third link. Each of the first link and the third link is connected so that two arms can rotate around an axis perpendicular to the predetermined plane, The two arms of the second link are connected to each other so as to be rotatable about an axis parallel to the predetermined plane.

  According to the above configuration, since the first link and the third link that are actively expanded and contracted are arranged so as to sandwich the second link, the load is not biased to either the first link or the second link. . Further, when the second link is bent, the joint portion is bent so as to be convex in a direction perpendicular to the predetermined plane, and when the first link and the third link are bent, the joint portion is parallel to the predetermined plane. Since they move and bend, they hardly interfere with each other mechanically. It should be noted that when the first link and the second link are bent so that the distance between the joints becomes a convex shape, even if the arrangement interval between the first link and the third link is narrow, the mutual link Mechanical interference can be prevented.

(10) In the three-degree-of-freedom parallel link mechanism, the first link includes a first drive motor fixed at a connection point with the base member, and rotational motion of the first drive motor. A first link power conversion mechanism that converts the first link to a bending and stretching motion, and the second link is fixed at a position of a connection point with the base member, and the reference of the second link with respect to the base member A third drive motor having a second drive motor that changes a direction around an axis, wherein the third link is fixed at a connection point with the base member; and rotation of the third drive motor. A power conversion mechanism for a third link that converts the motion into the bending and stretching motion of the third link.

  According to the above configuration, since each drive motor that drives each link is installed at the position of the connection point between each link and the base member, the moment acting on each link can be reduced.

(11) In the three-degree-of-freedom parallel link mechanism, the first link power conversion mechanism and the third link power conversion mechanism are configured by a parallel link mechanism.

  According to the said structure, since each power conversion mechanism is comprised with a parallel link mechanism, the rotational motion of a drive motor can be reliably converted into the bending motion of a link with a simple structure.

  As is clear from the above description, according to the transfer robot of the present invention, it is possible to flexibly cope with the transfer of articles that are produced in a variety of products in small quantities and variable quantities. Thus, even when the object is moved, the jackknife phenomenon does not occur, and the position, posture, and force during operation can be easily controlled. Further, the three-degree-of-freedom parallel link mechanism of the present invention is suitable for the above-described transfer robot.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a perspective view of a transfer robot 10 according to an embodiment of the present invention, and FIG. 2 is a view showing a transfer operation of the transfer robot 10 in a factory.
As shown in FIG. 1, the transport robot 10 is a robot for moving the article transport tool 1. The article 7 is a part, a semi-finished product, a finished product, or the like in the present embodiment, but is not particularly limited. The article transporter 1 is placed on the article 7 and receives an external force to move. Therefore, as the article transporter 1, for example, a hand cart or a cart shown in FIG. In the following, for convenience of explanation, reference numeral “1” is also used for “handcart”.
The transfer robot 10 includes a robot main body 12 that moves, a parallel link mechanism 20 that is connected to the robot main body 12, and a connection mechanism 40 that connects the parallel link mechanism 20 and the article transfer tool 1.

  A pair of drive wheels 14 driven by a drive motor (not shown) are provided on both the left and right sides of the lower portion of the body 13 of the robot body 12. The pair of drive wheels 14 are driven independently of each other with their rotational axes coinciding with each other. A free caster 15 is provided on the front and rear of the lower portion of the robot body 12 (see FIG. 3 for more details). With the above configuration, the robot body 12 can move forward and backward and turn left and right.

  The robot body 12 includes a drive motor for driving the drive wheel 14 described above, a control unit that controls the drive of the parallel link mechanism 20 and the coupling mechanism 40, a sensor 17 that detects an obstacle, and a host controller. A communication device that performs communication, a battery that supplies electric power necessary for driving these devices, and the like are mounted, and in response to a command from a host controller, an operation necessary for a transport operation is performed.

The parallel link mechanism 20 includes a plurality of links whose base ends are coupled to the robot body 12 and can be driven independently, and an output member 24 coupled to the distal ends of the plurality of links. Thus, the relative position and posture of the output member 24 with respect to the robot body 12 are determined.
In the present embodiment, the parallel link mechanism 20 includes a first link 21, a second link 22, and a third link 23 connected in parallel between the robot body 12 and the output member 24. The three-degree-of-freedom parallel link mechanism 20 is configured such that the relative position and posture of the output member 24 on the horizontal plane with respect to the robot body 12 are determined by the driving states of the second link 22 and the third link 23.

  Note that the parallel link mechanism 20 may be configured such that the relative position and posture of the output member 24 with respect to the robot body 12 in the space are determined by the driving states of the plurality of links. The parallel link mechanism 20 in this case is not particularly limited, but may be configured as, for example, a 6-degree-of-freedom parallel link mechanism called a Stuart platform.

The connection mechanism 40 is connected to the output member 24 of the parallel link mechanism 20, and connects the parallel link mechanism 20 and the article transporter 1 so that the relative position and posture between the output member 24 and the article transporter 1 can be fixed. And a function of performing separation.
In the present embodiment, the connection mechanism 40 is configured by two grip mechanisms 41 that are connected to the hand cart 1 by gripping the grip portion 2 provided on the hand cart 1 in the left-right direction.
The installation position of the parallel link mechanism 20 with respect to the robot body 12 is set to a height at which the connecting mechanism 40 can hold and connect the grip portion 2 of the article transport carriage.

  According to the transport robot 10 described above, the robot body is connected to the article transport tool 1 by the connection mechanism 40 and the relative position and posture of the article transport tool 1 are controlled by the parallel link mechanism 20 connected to the connection mechanism 40. By moving 12, the article transport tool 1 can be moved as shown in FIG. 2, and thereby the article 7 can be transported. The transport robot 10 can also move the article transport tool 1 by a pulling operation.

  Thus, unlike the conventional AGV, since it is not a transfer by a dedicated transfer stand integrated with the robot but a transfer mode in which the moving function and the article loading function are separated, the article transporter 1 that performs the article loading function is as follows. As shown in FIG. 2, the same thing as the person 8 (handcart 1, cart, etc.) can be used. Therefore, unlike the conventional AGV, it is possible to easily change the article conveying tool 1 to a suitable size according to the quantity / variety and to prepare a plurality of types of conveying robots 10 according to the quantity. There is no space and energy.

  In addition, since the transfer robot 10 is not integrated with the transfer stand, it can be reduced in size and weight as compared with the conventional AGV, so that the transfer robot 10 is in an abnormal state and becomes inoperable. Even in this case, it can be easily removed from the transfer line. Further, since the article conveying tool 1 can be used in common with the person 8, the person 8 can take over the conveying work in place of the conveying robot 10 which has become inoperable.

  Moreover, since the relative position and attitude | position of the parallel link mechanism 20 and the article transport tool 1 are fixed by the connection mechanism 40, even when moving the article transport tool 1 by pushing operation, a jackknife phenomenon does not arise. Therefore, even in a non-holonomic type transfer robot 10 that cannot move sideways, the article transfer tool 1 is accurately stopped at the target location by moving the article transfer tool 1 by a pushing operation in the vicinity of the target movement location. be able to.

  Further, since the parallel link mechanism 20 is employed as a mechanism for controlling the relative position and posture of the article transporter 1 with respect to the robot body 12, when controlling the relative position and posture on the plane, as in this embodiment. 3 freedom is required, and even if the relative position and posture in the space are controlled, 6 degrees of freedom are sufficient, so compared with two arms (12 degrees of freedom) that move almost the same as a human arm, Control of necessary position, posture, force, etc. becomes easy.

Hereinafter, the configuration of the transfer robot 10 of the present invention will be described in more detail. FIG. 3 is a schematic diagram of the transfer robot 10 and the hand cart 1, (A) is a plan view, and (B) is a side view.
3A and 3B, the left-right direction of the paper is the front-rear direction of the transfer robot 10. As shown in FIG. 3, the hand cart 1 is provided on the left and right sides of the lower surface of the loading platform 3, the loading platform 3 on which the article 7 is placed, the pair of universal casters 5 provided on the left and right sides of the lower surface of the loading platform 3. The pair of fixed casters 6, the support member 4 extending upward from the position behind the upper surface of the loading platform 3, and the grip portion 2 supported by the upper end of the support member 4.

As described above, the parallel link mechanism 20 includes the first link 21, the second link 22, the third link 23, and the output member 24 connected to the tip of each link.
Each of the first link 21 and the third link 23 has one end connected to the robot body 12 so as to be rotatable about the vertical axis, and the other end connected to the output member 24 so as to be rotatable about the vertical axis. At the same time, the distance between both ends is changed by driving.
The second link 22 is connected to the robot body 12 so that one end of the second link 22 can rotate around an axis center (hereinafter, this axis center is referred to as “reference axis a”), and the other end is vertically connected to the output member 24. While being connected rotatably about the axis, the direction around the reference axis a with respect to the robot body 12 is changed by driving. In addition, the distance between both ends of the second link 22 changes as the first link 21 and the third link 23 are driven.

  According to the above configuration, the first link 21, the second link 22, and the third link 23 are independently driven, so that the position and posture of the output member 24 can be set to three degrees of freedom in the plane (the traveling direction x on the horizontal plane). , The y-direction perpendicular to the x-direction on the horizontal plane, and the rotation angle θz around the z-axis perpendicular to the horizontal plane), the relative position and posture of the article transporter 1 relative to the robot body 12 on the horizontal plane can be controlled. Can be controlled.

FIG. 4 is a diagram schematically showing three types of configuration examples A, B, and C of the first link 21, the second link 22, and the third link 23.
In FIG. 4, each figure is shown in a frame of three rows in the left-right direction on the paper and in two steps up and down, and each configuration example A, B, and C is shown divided into each row in the left-right direction. In each row, the upper part is a schematic diagram in plan view, and the lower part is a schematic diagram in side view. In the schematic view in a side view, the upper side in the frame indicates the first link 21 (or the third link 23), and the lower side indicates the second link 22.
1 to 3 show the transfer robot 10 that employs the above configuration example C.

  As shown in FIG. 4, in each of the configuration examples A to C, the first link 21, the second link 22, and the third link 23 are each positioned at an intermediate position in the separation direction of the first link 21 and the third link 23. It arrange | positions so that the two links 22 may be located. Hereinafter, the configuration will be described for each configuration example.

[Configuration example A]
In the configuration example A, the first link 21, the second link 22, and the third link 23 are all configured to linearly expand and contract, and the first link 21 and the third link 23 are configured by an expansion / contraction drive actuator. It is configured. As the telescopic drive actuator, for example, a hydraulic cylinder device, a pneumatic cylinder device, or the like can be used. The second link 22 is linearly expandable and contractible, but the expansion and contraction is passive, and the second link 22 expands and contracts following the driving of the first link 21 and the second link 22. The second link 22 has a second drive motor 33 fixed at the position of the connection point with the robot main body 12, and the second drive motor 33 is driven to center on the reference axis a with respect to the robot main body 12. The direction is changed.

  According to the configuration example A, the output member 24 can be given translational movement by the expansion and contraction drive of the first link 21 and the third link 23, and the turning movement can be given to the output member 24 by the turning drive of the second link 22. Therefore, the position and posture of the output member 24 are controlled by three degrees of freedom in the plane (the traveling direction x on the horizontal plane, the y direction perpendicular to the x direction on the horizontal plane, and the rotation angle θz about the z axis perpendicular to the horizontal plane). be able to.

[Configuration example B]
In the configuration example B, each of the first link 21, the second link 22, and the third link 23 includes two arms 26 and 27 having a connection point at an intermediate portion between both ends (in this example, an intermediate point) The connecting points of the two arms 26 and 27 are bent and extended as joints 29, 30 and 31, and the distance between both ends is changed by this bending and extending movement.
The 1st link 21 and the 3rd link 23 have the 1st drive motor 32 and the 3rd drive motor 34 in the position of each joint 29 and 31, and bend and extend by the drive of each drive motor.
As shown in FIG. 4, the first link 21 and the third link 23 have two arms 26 and 27 connected to each other so as to be rotatable around a vertical axis.

The second link 22 has two arms 26 and 27 connected to each other so as to be rotatable about a horizontal axis, and can be expanded and contracted by bending and extending movements. However, the expansion and contraction is passive. The second link 22 is driven to expand and contract.
The second link 22 has a second drive motor 33 fixed at the position of the connection point with the robot main body 12, and the second drive motor 33 drives the second link 22 around the reference axis a with respect to the robot main body 12. The direction is changed.

According to the above configuration example B, similarly to the configuration example A, the position and orientation of the output member 24 can be controlled with three degrees of freedom in the plane. In addition, since each link has a joint, the range in which the distance between both ends changes (expansion / contraction range) can be expanded as compared with the configuration example A. Therefore, the movable range of the parallel link mechanism 20 can be expanded.
Further, since the first link and the third link that are actively expanded and contracted are arranged so as to sandwich the second link, the load is not biased to one of the first link and the second link. Further, when the second link is bent, the joint portion is bent so as to protrude upward or downward, and when the first link and the third link are bent, the joint portion moves in the horizontal direction and either Since they are bent so as to be convex in this direction, they hardly interfere with each other mechanically.
The direction in which the first link and the third link bend is not particularly limited, and may be a direction opposite to each other or a direction in which the distance between the joints 29 and 31 decreases, but as shown in FIG. This is the direction in which the distance between 29 and 31 increases. With this configuration, when each link is bent, the first link 21 and the third link 23 spread on both the left and right sides, so that mechanical interference between the links can be prevented.

[Configuration example C]
Since the configuration example C has many points in common with the configuration example B, the following description will focus on differences from the configuration example B.
In the configuration examples B and C, first, the installation positions of the first drive motor 32 and the third drive motor 34 are different. In the configuration example C, each of the first link 21 and the third link 23 has a first drive motor 32 and a third drive motor 34 at the position of the connection point with the robot body 12, and is bent and stretched by driving each drive motor. Do exercise.
In the configuration example C, the first link 21 has a first link power conversion mechanism 36a that converts the rotational motion of the first drive motor 32 into the bending and stretching motion of the first link 21, and the third link 23 is A third link power conversion mechanism 36 b that converts the rotational motion of the third drive motor 34 into the bending and stretching motion of the third link 23 is provided.

In the configuration example C, the first link power conversion mechanism 36a and the third link power conversion mechanism 36b are configured by a parallel link mechanism. Each parallel link mechanism includes a drive arm 37 connected to the output shaft of each drive motor 32, 34, a driven arm 38 connected to the arm 26 on the output member 24 side, and one end having a vertical axis on the drive arm 37. An intermediate arm 39 is rotatably connected to the center and the other end is connected to the driven arm 38 about the vertical axis. The drive arm 37 and the follower arm 38 have the same length, and the intermediate arm 39 has the same length as the arm 26 on the robot body 12 side.
The configuration of the other parts of the configuration example C is the same as that of the configuration example B.

According to the above configuration example C, in addition to the effects of the above configuration example B, the following effects can be obtained.
Since the drive motors 32, 33, 34 that drive the links 21, 22, 23 are provided at the connection points with the robot body 12, the moment acting on the links 21, 22, 23 can be reduced. Can do.
Further, by installing the drive motors 32, 33, and 34 at the above positions, the center of gravity of the entire transfer robot 10 can be easily set on the robot body 12 side, so that the transfer robot 10 stably moves and stops. be able to.
Since each power conversion mechanism 36a, 36b is configured by a parallel link mechanism, the rotational motion of each drive motor 32, 34 can be reliably converted into the bending motion of each link 21, 23 with a simple configuration.

  The first link power conversion mechanism 36a and the third link power conversion mechanism 36b are not limited to the parallel link mechanism described above, and use other mechanisms such as a belt transmission mechanism and a chain transmission mechanism. Also good.

FIG. 5 is a schematic plan view showing a state in which the transport robot 10 turns the hand cart 1.
As shown in FIG. 5, the turning trajectory drawn by the midpoint b of the rotation axis between the drive wheels 14 and 14 of the robot body 12 and the midpoint c of the rotation axis between the fixed casters 6 and 6 of the handcart 1 are shown. It is preferable to turn while the relative position and posture of the robot body 12 and the handcart 1 are controlled by the parallel link mechanism 20 so that the drawn turning trajectory is a circle having the same radius and the same center. By turning under such conditions, the transfer robot 10 and the handcart 1 can smoothly turn while drawing the same turning trajectory.

Further, the above three-degree-of-freedom parallel link mechanism 20 can be used not only for the transfer robot 10 of the present invention but also for other applications. For example, as shown in FIG. 6, instead of the robot body 12, the base end portions of the links 21, 22, and 23 are connected to the base member 43, and various tools 44 ( By attaching an article gripping tool, a processing tool, etc., it can be used as a transport mechanism of an article transport device or a positioning mechanism of a processing device.
In this case, the plane on which the relative position and orientation are controlled is not limited to a horizontal plane, and may be another plane, for example, a plane perpendicular to the horizontal plane.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

It is a perspective view of the conveyance robot concerning the embodiment of the present invention. It is a figure which shows the mode of the conveyance work of the conveyance robot in a factory. It is a schematic diagram of a conveyance robot and a hand cart. It is the figure which showed typically the structural examples A, B, and C of a 1st link, a 2nd link, and a 3rd link. It is a typical top view which shows a mode that the conveyance robot is turning the hand cart. It is a figure explaining another use of the 3 degree-of-freedom parallel link mechanism concerning the embodiment of the present invention.

Explanation of symbols

1 Goods carrier (handcart)
2 Grasping portion 3 Loading platform 4 Support member 5 Swivel caster 6 Fixed caster 7 Article 8 Person 10 Transport robot 12 Robot body 13 Body 14 Driving wheel 15 Swivel caster 17 Sensor 20 Parallel link mechanism 21 First link 22 Second link 23 Third Link 24 Output members 26, 27 Arms 29, 30, 31 Joint 32 First drive motor 33 Second drive motor 34 Third drive motor 36a First link power conversion mechanism 36b Third link power conversion mechanism 37 Drive arm 38 Followed Arm 39 Intermediate arm 40 Connection mechanism 41 Grip mechanism 43 Base member 44 Tool

Claims (11)

A transport robot that moves an article transporter that carries an article and receives an external force to move,
A robot body that moves,
A plurality of links whose base ends are connected to the mobile robot and can be driven independently; and output members connected to distal ends of the links; A parallel link mechanism in which a relative position and posture of the output member on a space or a plane are determined;
A connecting mechanism that is connected to the output member of the parallel link mechanism and connects and disconnects the parallel link mechanism and the article transporter so that the relative position and posture between the output member and the article transporter can be fixed. And a transport robot. The parallel link mechanism includes a first link, a second link, and a third link connected in parallel between the robot body and the output member, and driving the first link, the second link, and the third link. A three-degree-of-freedom parallel link mechanism in which a relative position and posture of the output member on the horizontal plane with respect to the robot body is determined depending on a state;
Each of the first link and the third link has one end connected to the robot body so as to be rotatable about a vertical axis and the other end is connected to the output member so as to be rotatable about the vertical axis. And the distance between both ends changes by driving,
One end of the second link is connected to the robot body so as to be rotatable about a reference axis that is vertically oriented, and the other end is connected to the output member so as to be rotatable about the vertical axis, and is driven. The direction around the reference axis with respect to the robot main body is changed by doing, and the distance between both ends is changed by driving the first link and the third link. The transfer robot according to claim 1.   Each of the first link, the second link, and the third link is composed of two arms having a connection point at the intermediate portion between the both ends, and is bent and stretched using the connection point of the two arms as a joint, The transport robot according to claim 2, wherein the distance between both ends is changed by bending and stretching movements. The first link, the second link, and the third link are arranged such that the second link is located at an intermediate position in the separation direction of the first link and the third link,
In the first link and the third link, two arms are connected to each other so as to be rotatable around a vertical axis,
The transport robot according to claim 3, wherein the two arms of the second link are connected to each other so as to be rotatable about a horizontal axis. The first link includes a first drive motor fixed at a position of a connection point with the robot body, and first link power conversion for converting the rotational motion of the first drive motor into the bending and stretching motion of the first link. A mechanism,
The second link has a second drive motor that is fixed at a position of a connection point with the robot body and changes a direction around the reference axis of the second link with respect to the robot body,
The third link includes a third drive motor fixed at a position of a connection point with the robot body, and a third link power conversion for converting the rotational motion of the third drive motor into the bending and stretching motion of the third link. The transfer robot according to claim 3, further comprising a mechanism.   The transfer robot according to claim 5, wherein the first link power conversion mechanism and the third link power conversion mechanism are configured by a parallel link mechanism. A base member, a base link connected to the base member, and a first link, a second link, and a third link that can be driven independently; and a distal end of the first link, the second link, and the third link A three-degree-of-freedom parallel in which a relative position and posture of the output member on a predetermined plane with respect to the base member are determined by driving states of the first link, the second link, and the third link. A link mechanism,
Each of the first link and the third link has one end connected to the base member so as to be rotatable about an axis perpendicular to the predetermined plane, and the other end connected to the output member with respect to the predetermined plane. In addition to being connected rotatably about a vertical axis, the distance between both ends changes by driving,
The second link has one end connected to the base member so as to be rotatable about a reference axis perpendicular to the predetermined plane, and the other end has an axis perpendicular to the predetermined plane to the output member. It is rotatably connected to the center, and when driven, the direction around the reference axis with respect to the base member changes, and is driven by the driving of the first link and the third link. A three-degree-of-freedom parallel link mechanism characterized in that the distance between both ends varies.   Each of the first link, the second link, and the third link is composed of two arms having a connection point at the intermediate portion between the both ends, and is bent and stretched using the connection point of the two arms as a joint, The three-degree-of-freedom parallel link mechanism according to claim 7, wherein a distance between the both ends is changed by bending and stretching movements. The first link, the second link, and the third link are arranged such that the second link is located at an intermediate position in the separation direction of the first link and the third link,
Each of the first link and the third link is connected so that two arms can rotate about an axis perpendicular to the predetermined plane.
9. The three-degree-of-freedom parallel link mechanism according to claim 8, wherein the two arms of the second link are coupled to each other so as to be rotatable about an axis parallel to the predetermined plane. The first link includes a first drive motor fixed at a position of a connection point with the base member, and first link power conversion for converting the rotational motion of the first drive motor into the bending and stretching motion of the first link. A mechanism,
The second link includes a second drive motor that is fixed at a connection point with the base member and changes a direction around the reference axis of the second link with respect to the base member;
The third link includes a third drive motor fixed at a position of a connection point with the base member, and a third link power conversion that converts the rotational motion of the third drive motor into the bending and stretching motion of the third link. The three-degree-of-freedom parallel link mechanism according to claim 8, further comprising a mechanism.   The three-degree-of-freedom parallel link mechanism according to claim 10, wherein the first link power conversion mechanism and the third link power conversion mechanism are configured by a parallel link mechanism.

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