Multi-joint robot system and method for controlling a multi-joint robot

Abstract

To move a tip end portion of a robot to the periphery of a base with simple control.SOLUTION: A robot 10 comprises: a body portion BDP; a tip end portion TP1; a plurality of links LK which include a link LK1 and a link LK2 and connect the body portion BDP and the tip end portion TP1; an articulating mechanism JEr3 which connects the link LK1 and the link LK2, and causes the link LK2 to rotate relative to the link LK1 with as an axis of rotation that is an axis AX3 forming more than a prescribed angle with a direction De1 in which the link LK1 extends; an articulating mechanism JEp1 which causes the articulating mechanism JEr3 to move relative to the link LK1 along the direction De1; and an articulating mechanism JEp2 which causes the link LK2 to move relative to the articulating mechanism JEp1 along a direction De2 in which the link LK2 extends.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an articulated robot, a control method for the articulated robot, a robot system, and a method for manufacturing an article. [Background technology]

[0002] 2. Description of the Related Art Articulated robots are known as robots that perform the same movements as humans (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 61-136782 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of conventional articulated robots, the arms of the robot interfere with each other, limiting the area that the tip of the robot can reach, narrowing the workable area of ​​the articulated robot. In particular, the arms are likely to interfere with each other around the base where the arms are attached, which is located at the base side of the robot, and many areas are outside the workable area. That is, in the case of a robot with two arms, the angle between the two arms approaches 0°, so the arms interfere with each other. Even if the workable area is within the workable area, the tip is controlled via the two arms, so there is a limit to how much precision can be improved. For this reason, it is desirable to control the tip of the robot with high precision, even around the base, without narrowing the workable area of ​​the articulated robot. [Means for solving the problem]

[0005] A preferred embodiment of the present invention provides an articulated robot comprising a base, a tip, a first link, and a second link, a plurality of links connecting the base and the tip, a first drive mechanism connecting the first link and the second link and rotating the second link relative to the first link about an axis that forms an angle with a first direction in which the first link extends that is greater than a predetermined angle, a first movement mechanism moving the first drive mechanism relative to the first link along the first direction, and a second movement mechanism moving the second link relative to the first drive mechanism along a second direction in which the second link extends.

[0006] A method for controlling a multi-joint robot according to a preferred embodiment of the present invention includes, in the multi-joint robot described above, further comprising a first motor for driving the first drive mechanism, a second motor for driving the first movement mechanism, and a third motor for driving the second movement mechanism, wherein the first movement mechanism includes a first screw portion disposed inside the first link and extending in the first direction, and rotating around an axis along the first direction as the second motor rotates, and a first movement portion connected to the first drive mechanism, through which the first screw portion is inserted, and moving relatively to the first screw portion as the first screw portion rotates, and the second movement mechanism is disposed inside the second link and extending in the second direction. a second screw portion that rotates about an axis along the second direction as the third motor rotates, and a second moving portion that is connected to the first driving mechanism, through which the second screw portion is inserted, and that moves relative to the second screw portion as the second screw portion rotates, wherein the first driving mechanism moves relative to the first link as the first moving portion moves, and the second link moves relative to the first driving mechanism as the second moving portion moves, wherein a control device that controls the operation of the multi-joint robot controls the operation of the multi-joint robot by controlling the first motor, the second motor, and the third motor.

[0007] A robot system according to a preferred aspect of the present invention is the multi-joint robot described above, further comprising a first motor that drives the first drive mechanism, a second motor that drives the first moving mechanism, and a third motor that drives the second moving mechanism, wherein the first moving mechanism comprises a first screw portion that is disposed inside the first link and extends in the first direction and rotates around an axis along the first direction as the second motor rotates, and a first moving portion that is connected to the first drive mechanism, has the first screw portion inserted therethrough, and moves relatively to the first screw portion as the first screw portion rotates, and the second moving mechanism is disposed inside the second link and extends in the second direction and rotates around the second direction as the third motor rotates. a second screw portion that rotates about an axis along the axis of rotation of the first motor, and a second moving portion connected to the first driving mechanism, through which the second screw portion is inserted, and that moves relative to the second screw portion as the second screw portion rotates, wherein the first driving mechanism moves relative to the first link as the first moving portion moves, and the second link moves relative to the first driving mechanism as the second moving portion moves, an end effector attached to the tip, and a control device that controls the operation of the multi-joint robot and the end effector, wherein the control device controls the operation of the multi-joint robot by controlling the first motor, the second motor, and the third motor.

[0008] In a method for manufacturing an article according to a preferred embodiment of the present invention, a part is assembled or removed by the above-mentioned robot system. Effect of the Invention

[0009] According to the present invention, the tip of the robot can be moved around the base with simple control. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram for explaining an overview of a robot system according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram for explaining an example of a joint mechanism. [Diagram 3] FIG. 2 is an explanatory diagram for explaining an example of a state of the robot shown in FIG. [Figure 4] 1. FIG. 4 is an explanatory diagram for explaining another example of the state of the robot shown in FIG. [Diagram 5] 2 is an explanatory diagram for explaining an operation showing an advantageous feature of the robot shown in FIG. 1. [Figure 6] 2 is a diagram illustrating an example of a hardware configuration of a robot controller illustrated in FIG. 1. [Figure 7] FIG. 11 is an explanatory view for explaining an example of a tip portion according to a first modified example. [Figure 8] FIG. 11 is an explanatory diagram for explaining an example of turning. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. In each drawing, the dimensions and scale of each part are appropriately different from the actual ones. In addition, the embodiments described below are preferred examples of the present invention, and therefore various technically preferable limitations are attached, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0012] [1. Embodiment] First, an example of an overview of a robot system 1 according to an embodiment will be described with reference to FIG.

[0013] FIG. 1 is an explanatory diagram for explaining an overview of a robot system 1 according to an embodiment.

[0014] The robot system 1 includes, for example, a robot 10, an end effector 20 that is detachably attached to the robot 10, and a robot controller 30 that controls the operations of the robot 10 and the end effector 20. The robot 10 is an example of a "multi-joint robot," and the robot controller 30 is an example of a "control device."

[0015] The robot 10 and the robot controller 30 are connected to each other so as to be able to communicate with each other, for example, by a wired connection. The connection between the robot 10 and the robot controller 30 may be a wireless connection, or a connection using both wires and wireless connections. The robot controller 30 is capable of communicating with the end effector 20 attached to the robot 10. The robot controller 30 may be any information processing device capable of communicating with other devices. The configuration of the robot controller 30 will be described later with reference to FIG. 6.

[0016] The robot 10 is an articulated robot used for work in, for example, farms, factories, warehouses, etc. Specifically, the robot 10 is an eight-axis articulated robot in which two joint mechanisms JEp (JEp1 and JEp2) corresponding to linear joints are added to a six-axis articulated robot having six joint mechanisms JEr (JEr1, JEr2, JEr3, JEr4, JEr5, and JEr6) corresponding to rotary joints. For example, the robot 10 has six joint mechanisms JEr, two joint mechanisms JEp, a body part BDP, two links LK (LK1 and LK2), and a tip part TP1. In the example shown in FIG. 1, the joint mechanism JEr1 is included in the body part BDP, and the joint mechanisms JEr5 and JEr6 are included in the tip part TP1. The joint mechanism JEp1 is provided in the link LK1, and the joint mechanism JEp2 is provided in the link LK2. Hereinafter, the joint mechanisms JEr and JEp are also referred to as the joint mechanism JE without any particular distinction. For example, the robot 10 further includes a plurality of motors that drive the plurality of joint mechanisms JE. In Fig. 1, in order to make the drawing easier to understand, the motors that drive the plurality of joint mechanisms JE, the reducers and encoders provided in each of the plurality of motors, and the like are omitted.

[0017] The body part BDP is an example of a "base part." In addition, the link LK1 is an example of a "first link," and the link LK2 is an example of a "second link." Therefore, the links LK1 and LK2 correspond to "multiple links." For example, the links LK1 and LK2 connect the body part BDP and the tip part TP1.

[0018] Here, for example, the connection of members includes both cases where two members are directly connected and cases where two members are indirectly connected. Two members being directly connected includes a state where two members are in contact with each other, and a state that can be regarded as equivalent to a state where two members are in contact with each other. A state that can be regarded as equivalent to a state where two members are in contact with each other is, for example, a state where one of the two members is fixed to the other by an adhesive or the like. Also, two members being indirectly connected means that another member is disposed between the two members.

[0019] Joint mechanism JEr1 is an example of a "second driving mechanism," and joint mechanism JEr2 is an example of a "third driving mechanism." Joint mechanism JEr3 is an example of a "first driving mechanism," and joint mechanism JEr4 is an example of a "fourth driving mechanism." Joint mechanism JEr5 is an example of a "fifth driving mechanism," and joint mechanism JEr6 is an example of a "sixth driving mechanism." Joint mechanism JEp1 is an example of a "first moving mechanism," and joint mechanism JEp2 is an example of a "second moving mechanism."

[0020] The body part BDP includes, for example, a base part BDPba fixed to a predetermined location such as a floor, and a joint mechanism JEr1 connected to the joint mechanism JEr2. The joint mechanism JEr1 rotates a part of the body part BDP around an axis Ax1 perpendicular to the bottom surface BDPbt of the body part BDP as a rotation axis. For example, the joint mechanism JEr1 rotates an outer wall including a part of the joint mechanism JEr1 connected to the joint mechanism JEr2, relative to the base part BDPba, around the axis Ax1 as a rotation axis. That is, the joint mechanism JEr1 rotates the joint mechanism JEr2 relative to the body part BDP, around the axis Ax1 as a rotation axis. The axis Ax1 is an example of a "second rotation axis."

[0021] Here, "vertical" includes not only strict vertical but also substantial vertical (e.g., vertical within a margin of error). Similarly, "parallel" described below includes not only strict parallel but also substantial parallel (e.g., parallel within a margin of error). The rotation direction Dr1 in FIG. 1 indicates the rotation direction of a portion of the body part BDP when the portion of the body part BDP rotates around the axis Ax1 as a rotation axis.

[0022] The joint mechanism JEr2 connects the body part BDP and the link LK1, and rotates the link LK1 relative to the body part BDP around an axis Ax2 parallel to the bottom surface BDPbt of the body part BDP. The rotation direction Dr2 in FIG. 1 indicates the rotation direction of the link LK1 when the link LK1 rotates around the axis Ax2. The axis Ax2 is an example of a "third rotation axis."

[0023] The link LK1 is, for example, hollow and long. The link LK1 has an opening Hlk1 extending in a direction De1 along which the link LK1 extends. The direction De1 is an example of a "first direction."

[0024] The opening Hlk1 is formed, for example, in a surface of the link LK1 that includes a portion facing the link LK2. A part of the joint mechanism JEr3 and the joint mechanism JEp1 are provided inside the link LK1. For example, a part of the joint mechanism JEr3 is located inside the link LK1, and the other part of the joint mechanism JEr3 protrudes from the opening Hlk1 to the outside of the link LK1. Note that the part of the joint mechanism JEr3 protruding outside the link LK1 or a part of the part protruding outside the link LK1 passes through an opening Hlk2 of the link LK2 described later and is located inside the link LK2.

[0025] The link LK1 rotates relative to the body part BDP about an axis Ax1 as a rotation axis by the joint mechanism JEr1, and rotates relative to the body part BDP about an axis Ax2 as a rotation axis by the joint mechanism JEr2.

[0026] The joint mechanism JEr3 connects the link LK1 and the link LK2, and rotates the link LK2 relative to the link LK1 about an axis Ax3 perpendicular to the direction De1 in which the link LK1 extends. The rotation direction Dr3 in FIG. 1 indicates the rotation direction of the link LK2 when the link LK2 rotates about the axis Ax3. The axis Ax3 is an example of a "first rotation axis."

[0027] The joint mechanism JEp1 moves the joint mechanism JEr3 relative to the link LK1 along the direction De1. As a result of the joint mechanism JEr3 moving along the direction De1, the link LK2 moves relative to the link LK1 along the direction De1.

[0028] The link LK2 is, for example, hollow and long. The link LK2 has an opening Hlk2 extending in a direction De2 along which the link LK2 extends. The direction De2 is an example of a "second direction."

[0029] The opening Hlk2 is formed, for example, in a surface of the link LK2 that includes a portion facing the link LK1. A part of the joint mechanism JEr3 and the joint mechanism JEp2 are provided inside the link LK2. For example, a part of the joint mechanism JEr3 is located inside the link LK2, and the other part of the joint mechanism JEr3 protrudes from the opening Hlk2 to the outside of the link LK2.

[0030] The joint mechanism JEp2 moves the link LK2 relative to the joint mechanism JEr3 along the direction De2 in which the link LK2 extends. As a result, the link LK2 moves relative to the joint mechanism JEr3 along the direction De2. That is, the link LK2 moves relative to the link LK1 along the direction De2.

[0031] In this way, the link LK2 moves relative to the link LK1 along the direction De1 by the joint mechanism JEp1, and moves relative to the link LK1 along the direction De2 by the joint mechanism JEp2.

[0032] The joint mechanism JEr4 connects the link LK2 and the tip TP1, and rotates the tip TP1 relative to the link LK2 around an axis Ax4 perpendicular to the direction De2. The rotation direction Dr4 in FIG. 1 indicates the rotation direction of the tip TP1 when the tip TP1 rotates around the axis Ax4. The axis Ax4 is an example of a "fourth rotation axis."

[0033] For example, an end effector 20 that grips an article is attached to the tip part TP1. For example, the end effector 20 is attached to an end face TP1sf of the tip part TP1. The tip part TP1 includes a first part TP11 connected to the link LK2, a second part TP12 connected to the first part TP11, a joint mechanism JEr5, and a joint mechanism JEr6. The first part TP11 is connected to the link LK2 via, for example, a joint mechanism JEr4. Therefore, the first part TP11 rotates relative to the link LK2 around the axis Ax4 as a rotation axis.

[0034] The joint mechanism JEr5 connects the first part TP11 and the second part TP12, and rotates the second part TP12 relative to the first part TP11 around an axis Ax5 perpendicular to the axis Ax4. The rotation direction Dr5 in FIG. 1 indicates the rotation direction of the second part TP12 when the second part TP12 rotates around the axis Ax5. The axis Ax5 is an example of the "fifth rotation axis."

[0035] The joint mechanism JEr6 rotates at least a part of the tip part TP1 around an axis Ax6 perpendicular to the axis Ax5. In the example shown in FIG. 1, the joint mechanism JEr6 rotates the end face TP1sf of the tip part TP1 around the axis Ax6. That is, the joint mechanism JEr6 rotates a part (end face TP1sf) of the tip part TP1 to which the end effector 20 is attached around the axis Ax6. The rotation direction Dr6 in FIG. 1 indicates the rotation direction of the end face TP1sf when the end face TP1sf rotates around the axis Ax6. The axis Ax6 is an example of a "sixth rotation axis."

[0036] 1, the surface of the joint mechanism JEr6 corresponds to the end surface TP1sf. In a configuration in which the joint mechanism JEr6 is included in the second part TP12, the end surface of the second part TP12 may be the end surface TP1sf.

[0037] Furthermore, the work performed by the end effector 20 is not limited to gripping an object. As the end effector 20, an appropriate part (e.g., a robot hand, a robot finger, etc.) can be applied depending on the work purpose of the robot 10. That is, an end effector 20 suitable for various works is attached to the tip portion TP1.

[0038] In this embodiment, a rotation about an axis whose angle with a specific direction is greater than a predetermined angle is sometimes referred to as a "turn" to distinguish it from a rotation about an axis whose angle with a specific direction is equal to or smaller than the predetermined angle. The predetermined angle may be, for example, 45°. Note that the predetermined angle is not limited to 45°.

[0039] For example, in the rotation about each of the axes Ax1 and Ax2 as the rotation axis, the direction Dv1 perpendicular to the bottom surface BDPbt of the body part BDP corresponds to the specific direction. In this case, the axis Ax1 corresponds to an axis whose angle with the direction Dv1 perpendicular to the bottom surface BDPbt of the body part BDP is equal to or smaller than a predetermined angle, and the axis Ax2 corresponds to an axis whose angle with the direction Dv1 is greater than a predetermined angle. Therefore, the rotation of the link LK1 about the axis Ax2 as the rotation axis corresponds to a turn. Note that in this embodiment, since the body part BDP extends along the direction Dv1 perpendicular to the bottom surface BDPbt, the direction Deb in which the body part BDP extends may be the specific direction.

[0040] In addition, in the rotation about the axis Ax3, the direction De1 in which the link LK1 extends corresponds to a specific direction, and in the rotation about the axis Ax4, the direction De2 in which the link LK2 extends corresponds to a specific direction. In this case, the axis Ax3 corresponds to an axis that forms an angle with the direction De1 in which the link LK1 extends that is larger than a predetermined angle, and the axis Ax4 corresponds to an axis that forms an angle with the direction De2 in which the link LK2 extends that is larger than a predetermined angle. Therefore, the rotation of the link LK2 about the axis Ax3 and the rotation of the first part TP11 about the axis Ax4 correspond to turning.

[0041] In addition, in the rotation about the axis Ax5, the direction De11 corresponds to a specific direction, and in the rotation about the axis Ax6, the direction De12 corresponds to a specific direction. The direction De11 is a direction from an end of the first part TP11 opposite to a specific end to which the joint mechanism JEr5 is connected toward the specific end. The direction De11 may be regarded as a direction in which the first part TP11 extends. The direction De12 is a direction from an end of the second part TP12 opposite to a specific end (end including the end face TP1sf) to which the joint mechanism JEr6 is connected toward the specific end. The direction De12 may be regarded as a direction in which the second part TP12 extends.

[0042] When the direction De11 is a specific direction, the axis Ax5 corresponds to an axis whose angle with the direction De11 is equal to or smaller than a predetermined angle. When the direction De12 is a specific direction, the axis Ax6 corresponds to an axis whose angle with the direction De12 is equal to or smaller than a predetermined angle. In this embodiment, it is assumed that the direction De11 is perpendicular to the axis Ax4, and the direction De12 is perpendicular to the axis Ax5. In this case, the axis Ax5 whose angle with the direction De11 is equal to or smaller than a predetermined angle corresponds to an axis whose angle with the axis Ax4 is larger than a predetermined angle, and the axis Ax6 whose angle with the direction De12 is equal to or smaller than a predetermined angle corresponds to an axis whose angle with the axis Ax5 is larger than a predetermined angle.

[0043] In this manner, in this embodiment, each of the multiple parts of the robot 10 (such as the body part BDP, the link LK1, the link LK2, and the tip part TP1) can rotate about each of the axes Ax1, Ax2, Ax3, Ax4, Ax5, and Ax6 as a rotation axis, thereby enabling the robot 10 to perform the same movements as a human being.

[0044] For example, the link LK1 between the joint mechanism JEr2 and the joint mechanism JEr3 corresponds to the upper arm, and the link LK2 between the joint mechanism JEr3 and the joint mechanism JEr4 corresponds to the forearm. The robot 10 can perform an action simulating the twisting of a human waist by the joint mechanism JEr1, and can perform an action simulating the rotation of a shoulder by the joint mechanism JEr2. The robot 10 can perform an action simulating the rotation of an elbow by the joint mechanism JEr3, and can perform an action simulating the rotation of a wrist by the joint mechanism JEr4. The robot 10 can perform an action simulating the twisting of a wrist by the joint mechanism JEr5, and can perform an action simulating the twisting of a fingertip by the joint mechanism JEr6.

[0045] Furthermore, in this embodiment, the joint mechanism JEp1 provided in the link LK1 can move the link LK2 relative to the link LK1 along the direction De1 in which the link LK1 extends. Also, in this embodiment, the joint mechanism JEp2 provided in the link LK2 can move the link LK2 relative to the link LK1 along the direction De2 in which the link LK2 extends. Therefore, in this embodiment, the joint mechanisms JEp1 and JEp2 can easily move the tip part TP1 of the robot 10 to the periphery of the body part BDP. Also, in this embodiment, the joint mechanisms JEp1 and JEp2 can widen the area that the tip part TP1 (more specifically, the end face TP1sf) can reach, and therefore the area that the end effector 20 attached to the robot 10 can reach can be widened.

[0046] The configuration of the robot system 1 is not limited to the example shown in FIG. 1. For example, the robot controller 30 may be built into the robot 10. Although FIG. 1 assumes a case where the robot 10 is fixed to a predetermined location such as a floor, the robot 10 itself may be movable without being fixed to a predetermined location. The base part BDPba of the body part BDP may be fixed to a predetermined location such as a floor via a joint mechanism JEr1. In this case, the body part BDP may be defined without including the joint mechanism JEr1. In a configuration in which the base part BDPba is fixed to a predetermined location via the joint mechanism JEr1, the joint mechanism JEr1 may rotate the base part BDPba around the axis Ax1 as a rotation axis. In a configuration in which the base part BDPba is fixed to a predetermined location via the joint mechanism JEr1, the base part BDPba may be connected to the joint mechanism JEr2.

[0047] Next, an example of the joint mechanisms JEp1 and JEp2 will be described with reference to FIG.

[0048] FIG. 2 is an explanatory diagram for explaining an example of the joint mechanism JE. In FIG. 2, the joint mechanisms JEp1 and JEp2 and the joint mechanism JEr3 will be mainly described. In this embodiment, it is assumed that the motor MOr3 that drives the joint mechanism JEr3 moves integrally with the joint mechanism JEr3. For example, the motor MOr3 may be fixed to the joint mechanism JEr3. The motor MOr3 is an example of a "first motor." First, the joint mechanism JEp1 will be described.

[0049] The joint mechanism JEp1 and the motor MOp1 that drives the joint mechanism JEp1 are disposed inside the link LK1. For example, the motor MOp1 is attached inside the link LK1 at the end LK1ed1, which is closer to the body part BDP, of the two ends LK1ed (LK1ed1 and LK1ed2) of the link LK1. The motor MOp1 is an example of a "second motor." Note that, of the two ends LK1ed of the link LK1, the end LK1ed farther from the body part BDP.

[0050] The joint mechanism JEp1 includes, for example, a screw portion JEp11 extending along a direction De1, a nut JEp12, a connection portion JEp13, and a rail JEp14. The screw portion JEp11 is an example of a "first screw portion," and the nut JEp12 is an example of a "first moving portion."

[0051] One end of the threaded portion JEp11 is attached to the motor MOp1. For example, the threaded portion JEp11 is attached to the motor MOp1 so that the central axis of the threaded portion JEp11 (the central axis along the direction De1) coincides with the rotation axis of the motor MOp1, and is inserted into a nut JEp12. Then, the threaded portion JEp11 rotates around the central axis along the direction De1 as the rotation axis of the motor MOp1.

[0052] The connection part JEp13 includes, for example, a slider part JEp13a connected to the rail JEp14 so as to be movable along the direction De1, and a support part JEp13b supporting the nut JEp12 and the motor MOr3. For example, the nut JEp12 is fixed to the support part JEp13b so as not to rotate together with the screw part JEp11. In addition, the motor MOr3 is fixed to the support part JEp13b so as not to rotate itself.

[0053] It is not necessary to strictly distinguish between the slider portion JEp13a and the support portion JEp13b. For example, the motor MOr3 may be fixed to the slider portion JEp13a. The nut JEp12 may be fixed to the motor MOr3 without the support portion JEp13b. That is, the nut JEp12 only needs to be connected to the connection portion JEp13 or the like so that the relative position of the nut JEp12 with respect to the joint mechanism JEr3 does not change. In this way, the nut JEp12 is connected to the joint mechanism JEr3 via the connection portion JEp13 or the like.

[0054] The rail JEp14 includes two rod-shaped members JEp14a and JEp14b extending along the direction De1 and arranged parallel to each other. The shapes of the rod-shaped members JEp14a and JEp14b and the slider portion JEp13a are not particularly limited as long as the rod-shaped members JEp14a and JEp14b can support the slider portion JEp13a. The rail JEp14 is arranged, for example, between the opening Hlk1 and the screw portion JEp11 in the direction along the axis Ax2, and is attached to the inside of the link LK1. Note that the rail JEp14 does not have to be arranged between the opening Hlk1 and the screw portion JEp11 in the direction along the axis Ax2, as long as the joint mechanism JEr3 can move along the direction De1 with a part of the joint mechanism JEr3 protruding from the opening Hlk1.

[0055] The nut JEp12 is fixed to the connection part JEp13 so as not to rotate together with the threaded part JEp11, and therefore moves relative to the threaded part JEp11 along the direction De1 as the threaded part JEp11 rotates. As described above, the nut JEp12 is fixed to the connection part JEp13, etc. so that the relative position to the joint mechanism JEr3 does not change. That is, the joint mechanism JEr3 moves along the direction De1 together with the nut JEp12. For example, the joint mechanism JEr3 moves relative to the link LK1 as the nut JEp12 moves. In this way, the joint mechanism JEp1 movably supports the joint mechanism JEr3. It is preferable that the movement range of the joint mechanism JEr3 is from a region closer to the end LK1ed1 than the end LK1ed2 of the link LK1 to a region closer to the end LK1ed2 than the end LK1ed1. This makes it possible to set the substantial length (control length) of the link LK1 to a length equal to or less than half the length of the link LK1 to a length equal to or more than half the length of the link LK1. The substantial length of the link LK1 is, for example, the length along the direction De1 from the end LK1ed1 (for example, the intersection of the link LK1 and the axis Ax2) to the joint mechanism JEr3 (more precisely, the axis Ax3).

[0056] Here, the moving direction of the nut JEp12, i.e., the moving direction of the joint mechanism JEr3, is switched between the direction De1 and the opposite direction to the direction De1 by switching the rotation direction of the motor MOp1. For example, when the motor MOp1 rotates in a first rotation direction, the nut JEp12 moves in the direction De1, and when the motor MOp1 rotates in a second rotation direction that is the opposite rotation to the first rotation direction, the nut JEp12 moves in the opposite direction to the direction De1. Next, the joint mechanism JEp2 will be described.

[0057] The joint mechanism JEp2 and the motor MOp2 that drives the joint mechanism JEp2 are disposed inside the link LK2. For example, the motor MOp2 is attached inside the link LK2 at the end LK2ed1, which is the farthest from the tip end TP1, of the two ends LK2ed (LK2ed1 and LK2ed2) of the link LK2. The motor MOp2 is an example of a "third motor." Note that, of the two ends LK2ed of the link LK2, the end LK2ed2 is the end LK2ed closer to the tip end TP1.

[0058] The joint mechanism JEp2 includes, for example, a screw portion JEp21 extending along the direction De2, a nut JEp22, a connection portion JEp23, and a rail JEp24. The screw portion JEp21 is an example of a "second screw portion," and the nut JEp22 is an example of a "second moving portion."

[0059] One end of the threaded portion JEp21 is attached to the motor MOp2. For example, the threaded portion JEp21 is attached to the motor MOp2 so that the central axis of the threaded portion JEp21 (the central axis along the direction De2) coincides with the rotation axis of the motor MOp2, and is inserted into the nut JEp22. Then, the threaded portion JEp21 rotates around the central axis along the direction De2 as the rotation axis of the motor MOp2.

[0060] The connection part JEp23 includes, for example, a slider part JEp23a connected to the rail JEp24 so as to be relatively movable along the direction De2, and a support part JEp23b supporting the nut JEp22 and the joint mechanism JEr3. For example, the nut JEp22 is fixed to the support part JEp23b so as not to rotate together with the screw part JEp21. In addition, the support part JEp23b is connected to the joint mechanism JEr3 so as to rotate about an axis Ax3 (not shown in FIG. 2) as the rotation axis in accordance with the rotation of the motor MOr3. That is, the joint mechanism JEr3 rotates the support part JEp23b about the axis Ax3 as the rotation axis in accordance with the rotation of the motor MOr3.

[0061] It is not necessary to strictly distinguish between the slider portion JEp23a and the support portion JEp23b. For example, the joint mechanism JEr3 may be connected to the slider portion JEp23a. The nut JEp22 may be fixed to the slider portion JEp23a. That is, the nut JEp22 only needs to be connected to the connection portion JEp23 or the like so that the relative position of the nut JEp22 with respect to the joint mechanism JEr3 does not change. In this way, the nut JEp22 is connected to the joint mechanism JEr3 via the connection portion JEp23 or the like.

[0062] The rail JEp24 includes two rod-shaped members JEp24a and JEp24b that extend along the direction De2 and are arranged parallel to each other. The shapes of the rod-shaped members JEp24a and JEp24b and the slider portion JEp23a are not particularly limited as long as the rod-shaped members JEp24a and JEp24b can support the slider portion JEp23a. The rail JEp24 is, for example, arranged between the opening Hlk2 and the screw portion JEp21 in the direction along the axis Ax2, and is attached to the inside of the link LK2. Note that the rail JEp24 does not have to be arranged between the opening Hlk2 and the screw portion JEp21 in the direction along the axis Ax2, as long as the joint mechanism JEr3 can move along the direction De2 with a part of the joint mechanism JEr3 protruding from the opening Hlk2.

[0063] The nut JEp22 is fixed to the connection part JEp23 so as not to rotate together with the threaded part JEp21, and therefore moves relative to the threaded part JEp21 along the direction De2 as the threaded part JEp21 rotates. As described above, the nut JEp22 is fixed to the connection part JEp23 and the like so that the relative position to the joint mechanism JEr3 does not change. In addition, when the threaded part JEp11 is not rotating, that is, when the motor MOp1 is not rotating, the joint mechanism JEr3 is supported by the joint mechanism JEp1 so that the relative position of the joint mechanism JEr3 to the link LK1 does not change. Therefore, the link LK2 moves relative to the joint mechanism JEr3 along the direction De2 as the nut JEp22 moves relative to the threaded part JEp21. In this way, the joint mechanism JEp2 movably supports the link LK2. It is preferable that the movement range of the joint mechanism JEr3 is from a region closer to the end LK2ed1 than the end LK2ed2 of the link LK2 to a region closer to the end LK2ed2 than the end LK2ed1. This makes it possible to set the substantial length (control length) of the link LK2 to a length equal to or less than half the length of the link LK2 to a length equal to or more than half the length of the link LK2. The substantial length of the link LK2 is, for example, the length along the direction De2 from the joint mechanism JEr3 (more precisely, the axis Ax3) to the end LK2ed2 (for example, the intersection of the link LK2 and the axis Ax4).

[0064] When the screw portion JEp21 is not rotating, i.e., when the motor MOp2 is not rotating, the joint mechanism JEr3 is supported by the joint mechanism JEp2 so that the relative position with respect to the link LK2 does not change. The joint mechanism JEr3 can rotate the link LK2 with respect to the link LK1 regardless of the relative position with respect to the link LK1. The joint mechanism JEr3 can rotate the link LK2 with respect to the link LK1 regardless of the relative position with respect to the link LK2.

[0065] Here, the moving direction of the nut JEp22 relative to the threaded portion JEp21, i.e., the moving direction of the link LK2, is switched between the direction De2 and the direction opposite to the direction De2 by switching the rotation direction of the motor MOp2. For example, when the motor MOp2 rotates in a first rotation direction, the link LK2 moves in the direction opposite to the direction De2, and when the motor MOp2 rotates in a second rotation direction that is opposite to the first rotation direction, the link LK2 moves in the direction De2.

[0066] The configuration of the joint mechanism JEp is not limited to the example shown in Fig. 2. For example, a ball screw having multiple balls between a screw part JEp11 and a nut JEp12 may be used as an element of the joint mechanism JEp1. Similarly, a ball screw having multiple balls between a screw part JEp21 and a nut JEp22 may be used as an element of the joint mechanism JEp2.

[0067] Also, for example, a part of the motor MOr3 may be located inside the link LK1, another part of the motor MOr3 may be located outside the link LK1 from the opening Hlk1, and the entire joint mechanism JEr3 may be located inside the link LK2. Also, for example, the joint mechanism JEr3 may have a storage section that stores the motor MOr3. That is, the motor MOr3 may be provided inside the joint mechanism JEr3. Alternatively, the motor MOr3 may be regarded as one element of the joint mechanism JEr3. Similarly, the motor MOp1 may be regarded as one element of the joint mechanism JEp1, and the motor MOp2 may be regarded as one element of the joint mechanism JEp2.

[0068] Next, the joint mechanisms JEr1, JEr2, JEr4, JEr5 and JEr6 will be briefly described.

[0069] The joint mechanism JEr1 has, for example, a rotating part JEr11 and a housing JEr12 that houses the rotating part JEr11. The rotating part JEr11 rotates around the axis Ax1 as a rotation axis with the rotation of the motor MOr1 that drives the joint mechanism JEr1. For example, the rotating part JEr11 is attached to the motor MOr1 so as to be rotatable around the base part BDPba around the axis Ax1 as a rotation axis. In addition, the housing JEr12 rotates around the axis Ax1 as a rotation axis with the rotating part JEr11 as a rotation axis with the base part BDPba. For example, the housing JEr12 is connected to the base part BDPba so as to be rotatable around the axis Ax1 as a rotation axis with the base part BDPba. Furthermore, the housing JEr12 is connected to the joint mechanism JEr2. As a result, the joint mechanism JEr2 rotates around the axis Ax1 as a rotation axis with the rotation of the rotating part JEr11 as a rotation axis with the base part BDPba.

[0070] The motor MOr1 may be regarded as one element of the joint mechanism JEr1. The housing JEr12 may be fixed to the base BDPba, and the joint mechanism JEr2 may be attached to the rotating part JEr11 so as to be rotatable with respect to the housing JEr12 about the axis Ax1 as the rotation axis. In this case, the housing JEr12 may be regarded as one element of the base BDPba.

[0071] The joint mechanism JEr2 has, for example, a rotating part JEr21 and a housing JEr22 that houses a motor MOr2 that drives the joint mechanism JEr2. The rotating part JEr21 rotates around an axis Ax2 as a rotation axis with the rotation of the motor MOr2. For example, the rotating part JEr21 is attached to the motor MOr2 so as to be rotatable with respect to the housing JEr22 around the axis Ax2 as a rotation axis. Furthermore, the rotating part JEr21 is connected to a link LK1. Furthermore, the link LK1 is connected to the housing JEr22 so as to be rotatable with respect to the housing JEr22. As a result, the link LK1 rotates with respect to the housing JEr22 around the axis Ax2 as a rotation axis with the rotation of the rotating part JEr21. Furthermore, the motor MOr2 is attached inside the housing JEr22.

[0072] The motor MOr2 may be regarded as one element of the joint mechanism JEr2. In the example shown in Fig. 2, a part of the rotating part JEr21 is located inside the link LK1, and another part of the rotating part JEr21 is located inside the housing JEr22, but the entire rotating part JEr21 may be located inside the link LK1 or inside the housing JEr22.

[0073] The joint mechanism JEr4 has, for example, a rotating part JEr41 and a housing JEr42 that houses the rotating part JEr41. The rotating part JEr41 rotates around an axis Ax4 as a rotation axis in accordance with the rotation of a motor MOr4 that drives the joint mechanism JEr4. For example, the rotating part JEr41 is attached to the motor MOr4 so as to be rotatable with respect to the link LK2 around the axis Ax4 as a rotation axis. The motor MOr4 is attached inside the link LK2.

[0074] Furthermore, the housing JEr42 rotates with the rotating part JEr41 relative to the link LK2 around the axis Ax4 as a rotation axis. For example, the housing JEr42 is connected to the link LK2 so as to be rotatable with respect to the link LK2 around the axis Ax4 as a rotation axis. Furthermore, the housing JEr42 is connected to the first part TP11. As a result, the first part TP11 rotates with the housing JEr42 around the axis Ax4 as a rotation axis in accordance with the rotation of the rotating part JEr41.

[0075] The motor MOr4 may be regarded as one element of the joint mechanism JEr4. In the example shown in Fig. 2, the entire rotating part JEr41 is located inside the housing JEr42, but the entire rotating part JEr41 may be located inside the link LK2. Alternatively, a part of the rotating part JEr41 may be located inside the housing JEr42, and the other part of the rotating part JEr41 may be located inside the link LK2.

[0076] The joint mechanism JEr5 has, for example, a rotating part JEr51 and a housing JEr52 that houses a part of the rotating part JEr51. The rotating part JEr51 rotates around an axis Ax5 as a rotation axis in accordance with the rotation of a motor MOr5 that drives the joint mechanism JEr5. For example, the rotating part JEr51 is attached to the motor MOr5 so as to be rotatable with respect to the first part TP11 around the axis Ax5 as a rotation axis. The motor MOr5 is attached inside the housing JEr42 of the joint mechanism JEr4.

[0077] Furthermore, the housing JEr52 rotates with respect to the first part TP11 together with the rotating part JEr51, with the axis Ax5 as the rotation axis. For example, the housing JEr52 is connected to the first part TP11 so as to be rotatable with respect to the first part TP11 around the axis Ax5 as the rotation axis. Furthermore, the housing JEr52 is connected to the second part TP12. As a result, the second part TP12 rotates with the housing JEr52 together with the axis Ax5 as the rotation axis in accordance with the rotation of the rotating part JEr51.

[0078] The motor MOr5 may be regarded as one element of the joint mechanism JEr5. In the example shown in Fig. 2, a part of the rotating part JEr51 is located inside the housing JEr52, and another part of the rotating part JEr51 is located inside the first part TP11, but the entire rotating part JEr51 may be located inside the housing JEr52 or inside the first part TP11.

[0079] The joint mechanism JEr6 has, for example, a rotating part JEr61 and a housing JEr62 that houses a part of the rotating part JEr61. The rotating part JEr61 rotates around the axis Ax6 as a rotation axis with the rotation of the motor MOr6 that drives the joint mechanism JEr6. For example, the rotating part JEr61 is attached to the motor MOr6 so as to be rotatable with respect to the second part TP12 around the axis Ax6 as a rotation axis. In addition, the housing JEr62 rotates with respect to the second part TP12 around the axis Ax6 as a rotation axis together with the rotating part JEr61. For example, the housing JEr62 is connected to the second part TP12 so as to be rotatable with respect to the second part TP12 around the axis Ax6 as a rotation axis. In addition, the housing JEr62 includes an end face TP1sf. For example, the end face TP1sf rotates with respect to the second part TP12 around the axis Ax6 as a rotation axis with the rotation of the rotating part JEr61.

[0080] The motor MOr6 may be regarded as one element of the joint mechanism JEr6. The housing JEr62 may be fixed to the second part TP12, and the end effector 20 may be attached to the surface of the rotating part JEr61 so as to be rotatable relative to the housing JEr62. In this case, the surface of the rotating part JEr61 corresponds to the end surface TP1sf. When the housing JEr62 is fixed to the second part TP12, the housing JEr62 may be regarded as one element of the second part TP12.

[0081] Furthermore, the multiple joint mechanisms JEr are not limited to the example shown in Fig. 2. For example, each of the multiple joint mechanisms JEr may have the same configuration as a mechanism corresponding to each joint of a known articulated robot.

[0082] Next, states (postures) that represent the characteristics of the robot 10 in this embodiment will be described. The states of the links LK1 and LK2 in the robot 10 can transition to a number of unique states, including a first state, a second state, and a third state, which will be described below. Note that the states (postures) that represent the characteristics of the robot 10 in this embodiment are not limited to the first state, the second state, and the third state.

[0083] [First state] First, the first state will be described with reference to FIG.

[0084] Fig. 3 is an explanatory diagram for explaining an example of a state of the robot 10 shown in Fig. 1. The state of the links LK1 and LK2 shown in Fig. 3 is a first state. In Fig. 3, the same members as those in Figs. 1 and 2 are given the same reference numerals. In Fig. 3, in order to make the drawing easier to see, some of the elements (e.g., rail JEp14, etc.) that are not used in the description of the first state are omitted.

[0085] As shown in FIG. 3, the direction De1 is parallel to the axis Ax1, and the axis Ax3 is located closer to the end LK1ed1 than the end LK1ed2 of the link LK1, and closer to the end LK2ed2 than the end LK2ed1 of the link LK2. As a result, the length from the end LK1ed1 to the axis Ax3, which is the substantial link length (arm length) of the link LK1, is less than half the length of the link LK1. Also, the length from the axis Ax3 to the end LK2ed2, which is the substantial link length (arm length) of the link LK2, is less than half the length of the link LK2. Therefore, the area where the link LK1 and the link LK2 interfere with each other is very small, and the tip part TP1 can be easily moved to the periphery of the body part BDP, making it possible to easily perform work around the body part BDP of the robot 10.

[0086] Furthermore, in the first state, the joint mechanisms JEr2, JEr3, and JEr4 do not approach each other in a straight line, so that the robot 10 can perform work around the body part BDP without worrying about singular points. A singular point is, for example, a posture of the robot 10 that makes it impossible to control the robot 10. As described above, in this embodiment, since there is no need to consider singular points, the robot 10 can be operated safely when performing work in which the tip part TP1 is located around the body part BDP.

[0087] Furthermore, when the control of the tip part TP1 around the body part BDP is performed by the joint mechanism JEr2 by the motor MOr2 and the joint mechanism JEr3 by the motor MOr3, the control accuracy depends on the substantial link length of the links LK1 and LK2. The shorter the substantial link length of the links LK1 and LK2, the higher the accuracy of the control becomes, and the vibration control performance when the tip part TP1 is stopped is improved. In the case of the first state of this embodiment, since the substantial link length of the links LK1 and LK2 is short, the position accuracy and vibration control performance of the tip part TP1 can be improved.

[0088] In the first state, the direction De1 does not necessarily have to be parallel to the axis Ax1, and the link LK1 may be inclined with respect to the axis Ax1 as long as the tip part TP1 can be positioned around the body part BDP.

[0089] [Second state] 2, the second state is a state in which the directions De1 and De2 are parallel to the axis Ax1, and the end LK2ed1 of the link LK2 is located closer to the end LK1ed1 than the end LK1ed2 of the link LK1. At this time, the axis Ax3 is located closer to the end LK1ed1 than the end LK1ed2 of the link LK1, and is located closer to the end LK2ed1 than the end LK2ed2 of the link LK2.

[0090] In the second state, the orientation of the links LK1 and LK2 is maintained so that the links LK1 and LK2 extend along the axis Ax1. In this case, the inertial force when the robot 10 is rotated about the axis Ax1 can be made smaller than when the orientation of the links LK1 and LK2 is such that one or both of the links LK1 and LK2 extend along a direction intersecting the axis Ax1.

[0091] Therefore, in this embodiment, by setting the state of the links LK1 and LK2 to the second state, the inertial force caused by the physical length and weight of the robot arm (links LK1 and LK2) can be reduced. As a result, in this embodiment, the robot 10 can be precisely controlled. For example, in this embodiment, the influence of vibration (vibration damping) when the operation of the robot 10 is stopped can be reduced. Therefore, in this embodiment, it is possible to achieve a reduction in the total operation time of the robot 10 when the robot 10 performs a predetermined task, and an improvement in operation accuracy, etc.

[0092] In the second state, the position of the joint mechanism JEr3 (more precisely, the axis Ax3) is not particularly limited as long as the directions De1 and De2 are parallel to the axis Ax1 and the end LK2ed1 of the link LK2 is located closer to the end LK1ed1 than the end LK1ed2 of the link LK1. For example, the position of the joint mechanism JEr3 in the second state may be closer to the end LK1ed1 than the end LK1ed2 of the link LK1, and closer to the end LK1ed1 than the end LK1ed2 of the link LK2, as shown in FIG. 2. Alternatively, the position of the joint mechanism JEr3 in the second state may be closer to the end LK1ed2 than the end LK1ed1 of the link LK1, and closer to the end LK1ed2 than the end LK1ed1 of the link LK2.

[0093] In addition, the state of the links LK1 and LK2 that reduces the inertial force when the robot 10 is rotated around the axis Ax1 is not limited to the second state as long as the links LK1 and LK2 are in a posture in which they extend along the axis Ax1. For example, the state of the links LK1 and LK2 may be close to the second state. The state close to the second state may be, for example, a state in which the directions De1 and De2 are parallel to the axis Ax1 and the end LK2ed1 of the link LK2 is located closer to the end LK1ed2 than the end LK1ed1 of the link LK1. In this case, the links LK1 and LK2 extend along the axis Ax1, and the link LK2 is located so that the tip TP1 is away from the link LK1. That is, in this embodiment, the state of the links LK1 and LK2 is set to the second state or a state close to the second state, thereby making it possible to reduce the inertial force when the robot 10 is rotated around the axis Ax1. However, the robot 10 is more stable when the tip TP1 is closer to the link LK1 than when the tip TP1 is farther from the link LK1.

[0094] Furthermore, in this embodiment, by setting the links LK1 and LK2 to the second state, the state of the robot 10 can be made compact, making it easier to carry the robot 10. Therefore, in this embodiment, it is possible to facilitate installation work when installing the robot 10 in a factory, or work to change the installation of the robot 10 due to equipment changes in the factory, etc.

[0095] [Third state] The state in which the robot 10 is made compact is not limited to the second state. Another example of the state in which the robot 10 is made compact will be described with reference to FIG.

[0096] Fig. 4 is an explanatory diagram for explaining another example of the state of the robot 10 shown in Fig. 1. The state of the links LK1 and LK2 shown in Fig. 4 is the third state.

[0097] The third state is a state in which the directions De1 and De2 are perpendicular to the axis Ax1, and the end LK2ed1 of the link LK2 is located closer to the end LK1ed1 than the end LK1ed2 of the link LK1. That is, in the third state, the orientations of the links LK1 and LK2 are maintained such that the links LK1 and LK2 extend along a direction perpendicular to the axis Ax1 (a direction parallel to the bottom surface BDPbt of the body part BDP).

[0098] In the third state, the robot 10 is compact, as in the second state. When the links LK1 and LK2 are in the third state, the robot 10 can be easily packed by using a cushioning member or the like having a recess corresponding to the portion protruding from the links LK1 and LK2 in the direction along the axis Ax1. The portion protruding from the links LK1 and LK2 in the direction along the axis Ax1 is, for example, a part of the tip portion TP1 and the body portion BDP.

[0099] In this manner, in this embodiment, by setting the links LK1 and LK2 to the third state, the state of the robot 10 can be made compact, and it becomes easier to carry the robot 10. Note that, in the third state as well, similarly to the second state, the position of the joint mechanism JEr3 (more precisely, the axis Ax3) is not particularly limited.

[0100] [Characteristic behavior] Next, with reference to Figures 5(a) and (b), a description will be given of operations that represent advantageous features of the robot 10 in this embodiment shown in Figure 1. Note that the operations that represent the features of the robot 10 in this embodiment are not limited to the operations that will be described below.

[0101] Fig. 5 is an explanatory diagram for explaining the operation showing the advantageous features of the robot 10 shown in Fig. 1. Fig. 5 illustrates the operation of the robot 10 when performing the task of moving an item GD placed on the lower level WBl of the work table WB to the upper level WBu of the work table WB, as an operation showing the advantageous features of the robot 10. For example, Fig. 5(a) is an explanatory diagram for explaining the operation when performing the task on the item GD placed on the lower level WBl of the work table WB, and Fig. 5(b) is an explanatory diagram for explaining the operation when performing the task on the item GD placed on the upper level WBu of the work table WB.

[0102] For convenience of explanation, in Fig. 5(a)(b), a three-axis Cartesian coordinate system having an X-axis, a Y-axis, and a Z-axis perpendicular to each other is introduced. Hereinafter, the direction indicated by the X-axis arrow is referred to as the +X direction, and the opposite direction of the +X direction is referred to as the -X direction. Hereinafter, the direction indicated by the Y-axis arrow is referred to as the +Y direction, and the opposite direction of the +Y direction is referred to as the -Y direction. Hereinafter, the +Y direction and the -Y direction may be referred to as the Y direction without any particular distinction, and the +X direction and the -X direction may be referred to as the X direction without any particular distinction. Hereinafter, the +Z direction and the -Z direction may be referred to as the Z direction without any particular distinction. Hereinafter, the -Z direction may be referred to as the downward direction.

[0103] 5(a) and (b), the advantages of the robot 10 will be described using as an example the task of moving an object GD placed on the lower level WBl of the work table WB to the upper level WBu of the work table WB, as described above. For example, the work table WB is placed around the body part BDP of the robot 10. Note that FIG. 5(a) assumes the operation from the first state in which the tip part TP1 is located around the body part BDP of the robot 10, as described above with reference to FIG. 3. First, a robot 10Z of a first comparative example that is compared with the robot 10 will be described. Note that the robot 10Z is shown by dotted lines in FIG. 5(a) for ease of understanding.

[0104] The robot 10Z is similar to the robot 10, except that the joint mechanisms JEp1 and JEp2 are omitted from the robot 10, the links LK1 and LK2 are replaced with links LK1z and LK2z, and the joint mechanism JEr3z is replaced with the joint mechanism JEr3. The joint mechanism JEr3z connects one end of the link LK1z to one end of the link LK2z, and rotates the link LK2z relative to the link LK1z about an axis Ax3z perpendicular to the direction in which the link LK1z extends. The relative positions of the joint mechanism JEr3z to the links LK1z and LK2z do not change. In the first comparative example, it is assumed that the central axis of the link LK1z and the central axis of the link LK2z are aligned in the direction along the axis Ax3z. In this case, the minimum value of the angle between the link LK1z and the link LK2z is limited to, for example, about 30° because the links LK1z and LK2z interfere with each other. Therefore, even if the angle between the link LK1z and the link LK2z is reduced to move the tip part TP1 closer to the body part BDP, the link LK1z and the link LK2z interfere with each other, and an area where the tip part TP1 cannot be moved closer to the body part BDP occurs. Therefore, the robot 10Z cannot work on the object GD placed on the workbench WB around the body part BDP, or cannot perform the desired work.

[0105] In contrast, the robot 10 of this embodiment can move the tip part TP1 close to the body part BDP as in the above-mentioned first state by controlling the joint mechanisms JEr2 and JEr3 and the joint mechanisms JEp1 and JEp2.

[0106] For example, the joint mechanism JEr2 rotates the link LK1 and supports the link LK1 at a position where the direction De1 in which the link LK1 extends is parallel to the axis Ax1. The joint mechanism JEp1 also moves the joint mechanism JEr3 along the direction De1 and supports the joint mechanism JEr3 at a position closer to the end LK1ed1 of the link LK1 than the end LK1ed2 of the link LK1. That is, the joint mechanism JEr3 is located downward (-Z direction) within the link LK1. The joint mechanism JEp2 also moves the link LK2 along the direction De2 and supports the link LK2 at a position where a movable space can be secured for the link LK2 and the tip portion TP1. For example, the joint mechanism JEp2 moves the link LK2 along the direction De2 so that the joint mechanism JEr3 is located closer to the end LK2ed2 of the link LK2 than the end LK2ed1 of the link LK2. Then, the joint mechanism JEr3 rotates the link LK2 so that the tip part TP1 is positioned around the body part BDP.

[0107] As a result, the tip part TP1 becomes in the state shown in the first state and moves to the periphery of the body part BDP. For example, in this embodiment, by controlling the joint mechanism JEr4 and the joint mechanisms JEr5 and JEr6 of the tip part TP1, it is possible to cause the robot 10 to perform various tasks in the periphery of the body part BDP.

[0108] In other words, in the robot 10 of this embodiment, even in areas where the movement of the tip TP1 is hindered by the links LK1 and LK2 in the robot 10Z of the first comparative example, the robot can easily reach and work in areas by controlling one or both of the joint mechanisms JEp1 and JEp2, making it possible to set a wide workable area.

[0109] As a comparative example in which the tip part TP1 can be moved close to the body part BDP, a form in which the central axis of the link LK1z of the robot 10Z and the central axis of the link LK2z are different from each other in the direction along the axis Ax3z (hereinafter, also referred to as a second comparative example) can be considered. The configuration of the robot 10Z in the second comparative example is, for example, similar to the configuration in which the joint mechanism JEr3 of the robot 10 is fixed to the end LK1ed2 of the link LK1 and the end LK2ed1 of the link LK2. In the case of the second comparative example, the central axis of the link LK1z and the central axis of the link LK2z are offset, so that interference between the link LK1z and the link LK2z can be eliminated.

[0110] However, in the second comparative example, the control for moving the tip part TP1 close to the body part BDP and the control of the tip part TP1 around the body part BDP are controlled by rotating the entire links LK1z and LK2z. In contrast, in the case of the robot 10 of this embodiment, the substantial link lengths of the links LK1 and LK2 are short, so that the positional accuracy and vibration damping of the tip part TP1 can be improved.

[0111] In the second comparative example, when the tip part TP1 is moved from the far right side of FIG. 5(a) in the -Y direction to the periphery of the body part BDP, the work table WB becomes an obstacle and must be avoided. Therefore, the joint mechanism JEr2 rotates the link LK1z so that the joint mechanism JEr3z moves away from the work table WB in the -Y direction. Then, the joint mechanism JEr3z rotates the link LK2z so that the tip part TP1 is located near the joint mechanism JEr2. After that, the joint mechanisms JEr2 and JEr3z rotate the links LK1z and LK2z, respectively, so that the tip part TP1 is located near the body part BDP. This allows the tip part TP1 to move to the periphery of the body part BDP.

[0112] In the second comparative example, when moving an article GD placed on the lower level WBl of the work table WB to the upper level WBu of the work table WB, the work table WB is an obstacle and must be avoided to avoid collision. For this reason, for example, the joint mechanism JEr2 rotates the link LK1z so that the joint mechanism JEr3z moves away from the work table WB in the -Y direction while the end effector 20 is gripping the article GD. Then, the joint mechanism JEr3z rotates the link LK2z so that the tip part TP1 moves away from the joint mechanism JEr2. After that, the joint mechanisms JEr2 and JEr3z rotate the links LK1z and LK2z, respectively, so that the article GD gripped by the end effector 20 is placed on the upper level WBu of the work table WB.

[0113] Thus, in the second comparative example, in order to move into or out of the narrow space around the body part BDP, complex control using many joint mechanisms JE is required, and the movement of the entire robot becomes large.

[0114] In contrast, in the robot 10 according to the present embodiment, the joint mechanism JEp2 moves the link LK2 relative to the joint mechanism JEr3, thereby shortening the length from the joint mechanism JEr3 to the tip part TP1. Therefore, even when the tip part TP1 is moved, for example, from the far right side of FIG. 5(a) in the -Y direction to the periphery of the body part BDP, or when an article GD placed on the lower level WBl of the work table WB is moved to the upper level WBu of the work table WB, it is not necessary to rotate the link LK1 by the joint mechanism JEr2, and the tip part TP1 and the like can be moved by using the joint mechanism JE on the tip side of the joint mechanism JEr3. In particular, when the length from the joint mechanism JEr3 to the tip part TP1 is short, the link LK and the tip part TP1 can be moved in a narrower movable space than when the length from the joint mechanism JEr3 to the tip part TP1 is long.

[0115] For example, as shown in FIG. 5(b), the joint mechanism JEr3 rotates the link LK2 so that the direction De2 in which the link LK2 extends is perpendicular to the axis Ax1 (parallel to the surface of the upper stage WBu of the work table WB) when the end effector 20 is gripping the article GD. The joint mechanism JEp2 then moves the link LK2 relative to the joint mechanism JEr3 so that the article GD gripped by the end effector 20 overlaps with the upper stage WBu of the work table WB in a plan view from the Z direction. The joint mechanism JEp1 also moves the joint mechanism JEr3 along the direction De1, and places the article GD gripped by the end effector 20 on the upper stage WBu of the work table WB. This allows the article GD placed on the lower stage WBl of the work table WB to be moved to the upper stage WBu of the work table WB.

[0116] In this manner, in this embodiment, the robot 10 can be easily driven even when the space around the robot 10 is narrow. As a result, in this embodiment, the robot 10 can be efficiently caused to perform a task on the object GD placed in a location close to the body part BDP.

[0117] In addition, in this embodiment, as shown in FIG. 5(b), when the article GD placed on the upper stage WBu of the workbench WB is moved further in the +Y direction (moved further back), the joint mechanism JEp2 moves the link LK2 relative to the joint mechanism JEr3. In this way, in this embodiment, when the direction De2 in which the link LK2 extends is perpendicular to the Z direction (direction along the axis Ax1), the tip part TP1 can be moved linearly in the Y direction by driving only the joint mechanism JEp2. In this case, since only the joint mechanism JEp2 is driven, there is no need to consider singular points. In this way, in this embodiment, the tip part TP1 can be moved linearly with simple control.

[0118] For example, in an inverse trajectory calculation in which the amount of movement of each of a plurality of joint mechanisms JE is calculated from the position of the end effector 20, when there are a large number of joint mechanisms JE that perform rotational movements, the computation load tends to increase compared to when there are a small number of joint mechanisms JE that perform rotational movements. In this embodiment, when performing an inverse trajectory calculation to move the end effector 20 horizontally in the Y direction, it is only necessary to calculate the amount of movement in the Y direction (direction De2). Therefore, in this embodiment, it is possible to reduce the computation load when performing an inverse trajectory calculation or the like to move the end effector 20 horizontally in the Y direction, and the computation can be executed at high speed.

[0119] The operation of moving the tip part TP1 linearly in the Y direction may be performed in the third state described in FIG. 4. Even in this case, the tip part TP1 can be moved linearly in the Y direction with simple control. For example, in the third state (the third state shown in FIG. 4) in which the joint mechanism JEr3 is located at the end part LK1ed1 of the link LK1, the tip part TP1 can be moved linearly in the Y direction by driving only the joint mechanism JRp1. Also, in the third state in which the joint mechanism JEr3 is located at the end part LK1ed2 of the link LK1, the tip part TP1 can be moved linearly in the Y direction by driving only the joint mechanism JRp2. In the third state, the tip part TP1 may be moved linearly in the Y direction by driving both the joint mechanisms JRp1 and JEp2. For example, in the third state, the tip end TP1 may be moved linearly in the Y direction by driving both joint mechanisms JRp1 and JEp2 so that the joint mechanism JEr3 is positioned approximately midway between the end LK1ed1 of the link LK1 and the end LK2ed2 of the link LK2.

[0120] Even when the operation of moving the tip part TP1 linearly in the Y direction is performed in the third state, there is no need to consider the singular point, so the robot 10 can be operated safely. Note that the operation of moving the tip part TP1 linearly in the Z direction is performed with simple control, for example, by setting the states of the links LK1 and LK2 to the second state shown in FIG.

[0121] Next, the hardware configuration of the robot controller 30 will be described with reference to FIG.

[0122] FIG. 6 is a diagram illustrating an example of a hardware configuration of the robot controller 30 illustrated in FIG.

[0123] The robot controller 30 has a processing device 32 that controls each part of the robot controller 30, a memory 33 that stores various information, a communication device 34, an operation device 35 that accepts operations by an operator, etc., a display device 36, and a driver circuit 37.

[0124] The memory 33 includes, for example, one or both of a volatile memory such as a random access memory (RAM) that functions as a working area for the processing device 32 and a non-volatile memory such as an electrically erasable programmable read-only memory (EEPROM) that stores various information such as the control program PGr. The memory 33 may be detachable from the robot controller 30. Specifically, the memory 33 may be a storage medium such as a memory card that is detachable from the robot controller 30. The memory 33 may also be, for example, a storage device (e.g., online storage) that is communicatively connected to the robot controller 30 via a network or the like.

[0125] 6 stores a control program PGr. In this embodiment, the control program PGr includes, for example, an application program that causes the robot controller 30 to control the operation of the robot 10. However, the control program PGr may also include, for example, an operating robot system program that causes the processing device 32 to control each part of the robot controller 30.

[0126] The processing device 32 is a processor that controls the entire robot controller 30, and is configured to include, for example, one or more CPUs (Central Processing Units). The processing device 32 executes, for example, a control program PGr stored in the memory 33, and operates in accordance with the control program PGr to control the operation of the robot 10. The control program PGr may be transmitted from another device via a network or the like.

[0127] Furthermore, for example, when the processing device 32 is configured to include multiple CPUs, some or all of the functions of the processing device 32 may be realized by the multiple CPUs operating in cooperation with each other according to a program such as the control program PGr. Furthermore, the processing device 32 may be configured to include hardware such as a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), or an FPGA (Field Programmable Gate Array) in addition to one or more CPUs, or instead of some or all of the one or more CPUs. In this case, some or all of the functions of the processing device 32 may be realized by hardware such as a DSP.

[0128] The communication device 34 is hardware for communicating with an external device that exists outside the robot controller 30. For example, the communication device 34 has a function of communicating with the external device by short-range wireless communication. The communication device 34 may further have a function of communicating with the external device via a mobile communication network or a network.

[0129] The operation device 35 is an input device (for example, a keyboard, a mouse, a switch, a button, a sensor, etc.) that accepts input from the outside. For example, the operation device 35 accepts an operation by an operator and outputs operation information corresponding to the operation to the processing device 32. Note that, for example, a touch panel that detects contact with the display surface of the display device 36 may be adopted as the operation device 35.

[0130] The display device 36 is an output device such as a display that outputs to the outside. For example, the display device 36 displays an image under the control of the processing device 32. Note that the operation device 35 and the display device 36 may be integrated into one (for example, a touch panel).

[0131] The driver circuit 37 is hardware that outputs signals to drive the robot 10 under the control of the processing device 32. For example, the driver circuit 37 outputs signals to drive motors MOr1, MOr2, MOr3, MOr4, MOr5, MOr6, MOp1, MOp2, etc. to the robot 10 under the control of the processing device 32. Note that the motors MOr1, MOr2, MOr3, MOr4, MOr5, and MOr6 are motors that drive the joint mechanisms JEr1, JEr2, JEr3, JEr4, JEr5, and JEr6, respectively. Also, the motors MOp1 and MOp2 are motors that drive the joint mechanisms JEp1 and JEp2, respectively.

[0132] In this manner, the robot controller 30 controls the movement of the robot 10 by controlling the motors MOr1, MOr2, MOr3, MOr4, MOr5, MOr6, MOp1, and MOp2.

[0133] As described above, in this embodiment, the robot 10 has the body part BDP, the tip part TP1, the links LK1 and LK2 (multiple links LK) connecting the body part BDP and the tip part TP1, the joint mechanism JEr3, the joint mechanism JEp1, and the joint mechanism JEp2. The joint mechanism JEr3 connects the links LK1 and LK2, and rotates the link LK2 relative to the link LK1 around the axis Ax3, which forms an angle with the direction De1 in which the link LK1 extends that is larger than a predetermined angle, as a rotation axis (first rotation axis). The joint mechanism JEp1 moves the joint mechanism JEr3 relative to the link LK1 along the direction De1. The joint mechanism JEp2 moves the link LK2 relative to the joint mechanism JEr3 along the direction De2 in which the link LK2 extends.

[0134] Thus, in this embodiment, the joint mechanism JEp1 moves the joint mechanism JEr3 relative to the link LK1 along the direction De1, and the joint mechanism JEp2 moves the link LK2 relative to the joint mechanism JEr3 along the direction De2. As a result, in this embodiment, the tip part TP1 of the robot 10 can be moved to the periphery of the body part BDP by simple control.

[0135] In this embodiment, the robot 10 further includes joint mechanisms JEr1, JEr2, and JEr3. The joint mechanism JEr1 rotates at least a part of the body part BDP around an axis Ax1 that is a predetermined angle or less with respect to a direction perpendicular to the bottom surface BDPbt of the body part BDP as a rotation axis (second rotation axis). The joint mechanism JEr2 connects the body part BDP and the link LK1, and rotates the link LK1 around an axis Ax2 that is a predetermined angle or more with respect to a direction perpendicular to the bottom surface BDPbt of the body part BDP as a rotation axis (third rotation axis). The joint mechanism JEr4 connects the link LK2 and the tip part TP1, and rotates the tip part TP1 relative to the link LK2. As a result, in this embodiment, the tip part TP1 connected to the link LK2 can be moved to the periphery of the body part BDP connected to the link LK1 by simple control.

[0136] In this embodiment, the joint mechanism JEr4 rotates the tip part TP1 relative to the link LK2 around an axis Ax4 that forms an angle with the direction De2 larger than a predetermined angle as a rotation axis (fourth rotation axis). The tip part TP1 includes a first part TP11 connected to the link LK2, a second part TP12 connected to the first part TP11, a joint mechanism JEr5, and a joint mechanism JEr6. The joint mechanism JEr5 connects the first part TP11 and the second part TP12, and rotates the second part TP12 relative to the first part TP11 around an axis Ax5 that forms an angle with the axis Ax4 (fourth rotation axis) larger than a predetermined angle as a rotation axis (fifth rotation axis). The joint mechanism JEr6 rotates a portion of the tip part TP1 to which the end effector 20 is attached (for example, the end face TP1sf) about the axis Ax6, which forms an angle with the axis Ax5 (fifth rotation axis) larger than a predetermined angle, as a rotation axis (sixth rotation axis). In this manner, the present embodiment may be realized by adding the joint mechanisms JEp1 and JEp2 to a vertical six-axis articulated robot. For example, in the present embodiment, since the tip part TP1 includes the joint mechanisms JEr5 and JEr6, the joint mechanisms JEr4, JEr5, JEr6, etc., can cause the robot 10 to perform various tasks around the body part BDP.

[0137] In this embodiment, the state of the links LK1 and LK2 can be transitioned to a first state. The first state is a state in which the axis Ax3 (first rotation axis) is located closer to the end LK1ed1 of the link LK1, which is closer to the body part BDP, than the end LK1ed2 farther from the body part BDP, and is located closer to the end LK1ed2 of the link LK2, which is closer to the tip part TP1, than the end LK2ed1 farther from the tip part TP1, among the two ends LK2ed of the link LK2. Thus, in the first state, the axis Ax3 is located closer to the body part BDP. This makes it possible to shorten the length from the axis Ax3 to the tip part TP1 in the first state when the tip part TP1 is located around the body part BDP. For example, when the length from the axis Ax3 to the tip part TP1 is short, it is not necessary to widen the movable space of the link LK2 and the tip part TP1, compared to when the length from the axis Ax3 to the tip part TP1 is long. Therefore, in this embodiment, the robot 10 can be easily driven even when the space around the robot 10 is narrow. As a result, in this embodiment, the robot 10 can be efficiently caused to perform a task on the object GD placed in a location close to the body part BDP.

[0138] In this embodiment, the states of the links LK1 and LK2 can transition to the second state. The second state is a state in which the direction De1 and the direction De2 are parallel to the axis Ax1 (second rotation axis), and the end LK2ed1 of the two ends LK2ed of the link LK2, which is farther from the tip part TP1, is located closer to the end LK1ed1 closer to the body part BDP than the end LK1ed2 of the two ends LK1ed of the link LK1, which is farther from the body part BDP. In the second state, the links LK1 and LK2 extend along the axis Ax1, so that the inertial force when the robot 10 is rotated around the axis Ax1 can be reduced. Therefore, in this embodiment, by setting the state of the links LK1 and LK2 to the second state, the inertial force caused by the physical length and weight of the robot arm (links LK1 and LK2) can be reduced. As a result, in this embodiment, it is possible to reduce the total operating time of the robot 10 for a task including an operation of rotating the robot 10 around the axis Ax1 as the rotation axis, and to improve the operating accuracy.

[0139] In this embodiment, the robot 10 further includes a motor MOr3 for driving the joint mechanism JEr3, a motor MOp1 for driving the joint mechanism JEp1, and a motor MOp2 for driving the joint mechanism JEp2. The joint mechanism JEp1 includes a screw portion JEp11 and a nut JEp12. The screw portion JEp11 is disposed inside the link LK1, extends in a direction De1, and rotates around an axis along the direction De1 as the motor MOp1 rotates. The nut JEp12 is connected to the joint mechanism JEr3, has the screw portion JEp11 inserted therethrough, and moves relative to the screw portion JEp11 as the screw portion JEp11 rotates. The joint mechanism JEp2 includes a screw portion JEp21 and a nut JEp22. The screw portion JEp21 is disposed inside the link LK2, extends in a direction De2, and rotates around an axis along the direction De2 as the motor MOp2 rotates. The nut JEp22 is connected to the joint mechanism JEr3, the threaded portion JEp21 is inserted therethrough, and moves relative to the threaded portion JEp21 as the threaded portion JEp21 rotates. The joint mechanism JEr3 moves relative to the link LK1 as the nut JEp12 moves. The link LK2 moves relative to the joint mechanism JEr3 as the nut JEp22 moves. In this way, in this embodiment, the joint mechanisms JEp1 and JEp2 can be realized with a simple configuration.

[0140] In this embodiment, the robot controller 30 controls the motors MOr3, MOp1, and MOp2 to control the operation of the robot 10. In this manner, in this embodiment, the robot controller 30 can easily control the operation of the robot 10.

[0141] In addition, in this embodiment, the robot system 1 includes the robot 10, the end effector 20 attached to the tip part TP1, and a robot controller 30 that controls the operation of the robot 10 and the end effector 20. Thus, in this embodiment, the robot system 1 uses the robot 10 that can move the tip part TP1 to the periphery of the body part BDP by simple control. Therefore, in this embodiment, complex tasks and simple tasks can be efficiently performed even in a narrow space around the body part BDP. For example, the robot system 1 may be used in a manufacturing method of an article that includes assembling or removing a part. In this case, the task of assembling or removing a part can be efficiently performed.

[0142] [2. Modifications] The present invention is not limited to the above-described embodiments. Specific modified embodiments are exemplified below. Two or more embodiments selected from the following examples may be combined.

[0143] [First Modification] In the above embodiment, the joint mechanism JEr4 rotates the tip part TP1 relative to the link LK2 around the axis Ax4 perpendicular to the direction De2 in which the link LK2 extends, but the present invention is not limited to this. For example, the joint mechanism JEr4 may rotate the tip part TP1 relative to the link LK2 around an axis that forms an angle with the direction De2 in which the link LK2 extends that is equal to or smaller than a predetermined angle.

[0144] Fig. 7 is an explanatory diagram for explaining an example of a tip portion TP1A according to the first modified example. Elements similar to those explained in Fig. 1 to Fig. 6 are given the same reference numerals, and detailed explanations will be omitted.

[0145] For example, the robot 10 according to this modification is similar to the robot 10 shown in Fig. 1, except that it has a link LK2A, a joint mechanism JEr4A, and a tip part TP1A instead of the link LK2, joint mechanism JEr4, and tip part TP1 shown in Fig. 1. The link LK2A is similar to the link LK2, except that a joint mechanism JEr4A is connected instead of the joint mechanism JEr4. The link LK2A is another example of a "second link," and the joint mechanism JEr4A is another example of a "fourth drive mechanism."

[0146] The joint mechanism JEr4A connects the link LK2A and the tip TP1A, and rotates the tip TP1A relative to the link LK2A around an axis Ax4A parallel to the direction De2. The rotation direction Dr4 in FIG. 7 shows the rotation direction of the tip TP1A when rotating around the axis Ax4A. The axis Ax4A is another example of the "fourth rotation axis" and corresponds to an axis that forms an angle with the direction De2 in which the link LK2A extends that is equal to or smaller than a predetermined angle.

[0147] In the tip part TP1A, the end effector 20 is attached to the end surface TP1sf in the same manner as in the tip part TP1 shown in FIG. 1. The tip part TP1A includes a first part TP11A connected to the link LK2A, a second part TP12A connected to the first part TP11A, a joint mechanism JEr5A, and a joint mechanism JEr6. The first part TP11A is connected to the link LK2A via, for example, a joint mechanism JEr4A. Therefore, the first part TP11A rotates with respect to the link LK2A about the axis Ax4A as the rotation axis.

[0148] The joint mechanism JEr5A connects the first part TP11A and the second part TP12A, and rotates the second part TP12A relative to the first part TP11A around an axis Ax5 perpendicular to the axis Ax4A. The rotation direction Dr5 in FIG. 1 indicates the rotation direction of the second part TP12A when rotating around the axis Ax5.

[0149] The joint mechanism JEr6 is similar to the joint mechanism JEr6 shown in Fig. 1. For example, the joint mechanism JEr6 rotates at least a part (for example, end face TP1sf) of the tip part TP1A around an axis Ax6 perpendicular to the axis Ax5 as a rotation axis. In the example shown in Fig. 7, the surface of the joint mechanism JEr6 corresponds to the end face TP1sf, similar to the joint mechanism JEr6 shown in Fig. 1. Note that in a configuration in which the joint mechanism JEr6 is included in the second part TP12A, the end face of the second part TP12A may be the end face TP1sf.

[0150] As described above, in this modified example, the joint mechanism JEr4A rotates the tip part TP1A relative to the link LK2A around the axis Ax4A, which forms an angle with the direction De2 equal to or smaller than a predetermined angle as a rotation axis (fourth rotation axis). The tip part TP1A includes a first part TP11 connected to the link LK2A, a second part TP12 connected to the first part TP11, a joint mechanism JEr5, and a joint mechanism JEr6. The joint mechanism JEr5 connects the first part TP11 and the second part TP12, and rotates the second part TP12 relative to the first part TP11 around the axis Ax5, which forms an angle with the axis Ax4A (fourth rotation axis) greater than a predetermined angle as a rotation axis (fifth rotation axis). The joint mechanism JEr6 rotates a portion of the tip part TP1 to which the end effector 20 is attached (for example, the end face TP1sf) about an axis Ax6 (sixth rotation axis) whose angle with the axis Ax5 (fifth rotation axis) is larger than a predetermined angle.

[0151] In this modified example, the same effects as those of the above-described embodiment can be obtained. For example, in this modified example, the tip part TP1 includes the joint mechanisms JEr5 and JEr6, and therefore the joint mechanisms JEr4, JEr5, JEr6, etc. can cause the robot 10 to perform various tasks around the body part BDP.

[0152] [Second modified example] In the above-described embodiment and modified example, the motor MOr3 that drives the joint mechanism JEr3 moves integrally with the joint mechanism JEr3, but the present invention is not limited to such an embodiment. For example, the motor MOr3 may be fixed to a predetermined location of the link LK1 so as to be able to drive the joint mechanism JEr3 even if the relative position of the joint mechanism JEr3 with respect to the link LK1 changes. In this modified example, the same effects as those of the above-described embodiment and modified example can be obtained.

[0153] [Third Modification] In the above-described embodiment and modified example, the robot 10 is exemplified as a vertical six-axis articulated robot to which two joint mechanisms JEp1 and JEp2 are added, but the present invention is not limited to such an embodiment. For example, the robot 10 may be a seven-axis or more articulated robot to which two joint mechanisms JEp1 and JEp2 are added. Specifically, one or more links LK different from the links LK1 and LK2 may be disposed between the body part BDP and the joint mechanism JEr2. Alternatively, one or more links LK different from the links LK1 and LK2 may be disposed between the joint mechanism JEr4 and the tip part TP1. That is, the robot 10 may have three or more links LK connecting the body part BDP and the tip part TP1. In this case, the three or more links LK of the robot 10 correspond to a plurality of links LK including the links LK1 and LK2.

[0154] As described above, in this modified example as well, the same effects as those of the above-described embodiment and modified example can be obtained.

[0155] [3. Application Examples] The robot system 1 including the robot 10 described in the above-mentioned embodiment and modified examples may be used in a manufacturing method of an article including assembling or removing a part.

[0156] [4.Other] The distinction between the "turning" briefly explained in the above embodiment and other rotations will be described with some examples.

[0157] FIG. 8 is an explanatory diagram for explaining an example of turning. In FIG. 8, the distinction between turning and other rotations will be explained using the connection of two links LKi and LKj whose longitudinal directions can be grasped as an example. The extension direction Dei in FIG. 8 indicates the direction in which the link LKi extends, and the extension direction Dej indicates the direction in which the link LKj extends. In addition, the joint mechanism JEri in FIG. 8 connects the link LKi and the link LKj, and rotates the link LKj relative to the link LKi around the axis Axi as the rotation axis.

[0158] In the example shown in FIG. 8, when the angle θ between the extension direction Dei (specific direction) of the link LKi and the axis Axi is greater than a predetermined angle, the rotation about the axis Axi corresponds to a "turn". In other words, when the angle θ between the extension direction Dei of the link LKi and the axis Axi is equal to or less than a predetermined angle, the rotation about the axis Axi corresponds to a rotation other than a turn (a rotation other than a turn that is distinguished from a turn). The "rotation" shown in FIG. 8 indicates a rotation other than a turn. In addition, the predetermined angle is not particularly limited, but in FIG. 8, the predetermined angle is assumed to be 45°. The angle θ between the extension direction Dei and the axis Axi is an angle between 0° and 90° among a plurality of angles that are understood as the angle of the axis Axi with respect to the extension direction Dei (for example, four angles for two straight lines that intersect with each other, or 0° and 180° for two parallel straight lines).

[0159] In the first pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 90°, which is greater than a predetermined angle (45°). Therefore, in the first pattern, the rotation of the link LKj around the axis Axi is a turn. Also, in the first pattern, the extension direction Dej of the link LKj is perpendicular to the axis Axi. Note that in the first pattern, when the link LKj rotates (turns) around the axis Axi as the rotation axis, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi changes.

[0160] In the second pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 0°, which is less than a predetermined angle (45°). Therefore, in the second pattern, the rotation of the link LKj around the axis Axi is a rotation other than a turning. Also, in the second pattern, the extension direction Dej of the link LKj is parallel to the extension direction Dei of the link LKi and the axis Axi. That is, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is 0°. Note that in the second pattern, even if the link LKj rotates around the axis Axi as the rotation axis, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is maintained at 0° and is always constant.

[0161] In the third pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 0°, which is less than a predetermined angle (45°). Therefore, in the third pattern, the rotation of the link LKj around the axis Axi is a rotation other than a turning. Also, in the third pattern, the extension direction Dej of the link LKj is perpendicular to the extension direction Dei of the link LKi and the axis Axi. That is, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is 90°. Note that in the third pattern, even if the link LKj rotates around the axis Axi as the rotation axis, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is maintained at 90° and is always constant.

[0162] In the fourth pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 10°, which is less than the predetermined angle (45°). Therefore, in the fourth pattern, the rotation of the link LKj around the axis Axi is a rotation other than a turning. Also, in the fourth pattern, the extension direction Dej of the link LKj is parallel to the axis Axi, and the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is 10°. Note that in the fourth pattern, even if the link LKj rotates around the axis Axi, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is maintained at 10° and is always constant.

[0163] In the fifth pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 70°, which is greater than the predetermined angle (45°). Therefore, in the fifth pattern, the rotation of the link LKj around the axis Axi is a turn. Also, in the fifth pattern, the extension direction Dej of the link LKj is perpendicular to the axis Axi. Note that in the fifth pattern, when the link LKj rotates (turns) around the axis Axi, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi changes.

[0164] In the sixth pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 10°, which is less than the predetermined angle (45°). Therefore, in the sixth pattern, the rotation of the link LKj around the axis Axi is a rotation other than a turn. Also, in the sixth pattern, the extension direction Dej of the link LKj is perpendicular to the axis Axi. Note that in the sixth pattern, when the link LKj rotates around the axis Axi, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi changes.

[0165] In the seventh pattern, the angle θ between the extension direction Dei of the link LKi and the axis Axi is 70°, which is larger than the predetermined angle (45°). Therefore, in the seventh pattern, the rotation of the link LKj around the axis Axi is a turn. Also, in the seventh pattern, the extension direction Dej of the link LKj is parallel to the axis Axi, and the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is 70°. Note that in the seventh pattern, even if the link LKj rotates around the axis Axi, the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is maintained at 70° and is always constant.

[0166] In this way, in the above-described embodiment and modified example, among the rotations of the link LKj with respect to the link LKi, the rotation about the axis Axi, which forms an angle with the extension direction Dei of the link LKi larger than a predetermined angle, is also referred to as a turn. However, the definition of "turn" is not limited to the above example. For example, if the above definition that defines a turn as a rotation about the axis Axi, which forms an angle with the extension direction Dei of the link LKi larger than a predetermined angle, as the first definition, the following second or third definition may be adopted instead of the first definition.

[0167] In the second definition, when the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi changes due to the rotation of the link LKj with respect to the link LKi, the rotation corresponds to a turn. Therefore, in the second definition, when the angle of the extension direction Dej of the link LKj with respect to the extension direction Dei of the link LKi is always constant even if the link LKj rotates, the rotation corresponds to a rotation other than a turn. For example, in the second definition, the first, fifth, and sixth patterns shown in FIG. 8 correspond to turns, and the second, third, fourth, and seventh patterns correspond to rotation other than a turn.

[0168] In the third definition, when the angle between the extension direction Dej of the rotating link LKj and the rotation axis (axis Axi) of the link LKj is greater than a predetermined angle, the rotation corresponds to a turn. Therefore, in the third definition, when the angle between the extension direction Dej of the link LKj and the rotation axis (axis Axi) of the link LKj is equal to or smaller than a predetermined angle, the rotation corresponds to a rotation other than a turn. For example, in the third definition, the first, third, fifth and sixth patterns shown in FIG. 8 correspond to turns, and the second, fourth and seventh patterns correspond to rotation other than a turn.

[0169] In addition to the above-mentioned first, second and third definitions, the relative relationship between the two rotations by the two joint mechanisms JEr may be defined by focusing on the relationship between the rotation axes of the two joint mechanisms JEr adjacent to each other. Specifically, when the angle between the two rotation axes is equal to or less than a predetermined angle (typically parallel), the two rotations may be regarded as the same type of rotation, and when the angle between the two rotation axes is greater than a predetermined angle (typically perpendicular), the two rotations may be regarded as different types of rotation. The same type of rotation means that both rotations are rotations or both rotations are other than rotations, and the different type of rotation means that one of the two rotations is rotation and the other is other than rotation. When the definition of the relative relationship between the two rotations is used, the rotation that is the starting point of the relative relationship may be determined based on, for example, any of the above-mentioned first, second and third definitions. The first pattern shown in Fig. 8 corresponds to a rotation in any of the first, second and third definitions, and the second pattern corresponds to a rotation other than a rotation in any of the first, second and third definitions. Therefore, it is preferable to set the first pattern or the second pattern as the rotation that is the starting point of the relative relationship.

[0170] Also, a definition that combines two or more of the above-mentioned first, second, and third definitions may be used. In this case, for example, only a rotation that corresponds to a rotation in all of the two or more definitions to be combined may be considered as a rotation, or a rotation that corresponds to a rotation in at least one of the two or more definitions to be combined may be considered as a rotation. [Explanation of symbols]

[0171] 1...robot system, 10...robot, 20...end effector, 30...robot controller, 32...processing device, 33...memory, 34...communication device, 35...operation device, 36...display device, 37...driver circuit, Ax1, Ax2, Ax3, Ax3z, Ax4, Ax4A, Ax5, Ax6, Axi...axis, BDP...body part, BDPbt...bottom surface, BDPba...base part, GD...article, JEr1, JEr2, JEr3, JEr4, JEr4A, JEr5, JEr6, JEri, JEp1, JEp2...joint mechanism, JEp11, JEp21...screw part, JEp12, JEp22 ...nut, JEp13, JEp23...connection part, JEp13a, JEp23a...slider part, JEp13b, JEp23b...support part, JEp14, JEp24...rail, JEp14a, JEp14b, JEp24a, JEp24b...rod-shaped member, JEr11, JEr21, JEr41, JEr51, JEr61...rotating part, JEr12, JEr22, JEr42, JEr52, JEr62...housing, LK1, LK2, LK2A, LKi, LKj...link, MOr1, MOr2, MOr3, MOr4, MOr5, MOr6, MOp1, MOp2...motor, WB...workbench.

Claims

1. A multi-joint robot comprising a base, a tip, a plurality of links connecting the base and the tip, a first driving mechanism connecting the first link and the second link and rotating the second link relative to the first link about an axis at an angle greater than a predetermined angle with respect to a first direction in which the first link extends, a first moving mechanism moving the first driving mechanism relative to the first link along the first direction, and a second moving mechanism moving the second link relative to the first driving mechanism along a second direction in which the second link extends. A control device for operating the multi-joint robot by controlling the operations of the first driving mechanism, the first moving mechanism, and the second moving mechanism. It is provided with... A multi-joint robot system characterized by the above.

2. The first driving mechanism is disposed inside the first link and includes a portion that moves along the first direction within the length range of the first link and a portion that is connected to the second link and moves along the second direction within the length range of the second link. The second link moves relative to the first link along the second direction when the first driving mechanism moves relative to the second link along the second direction within the length range of the second link. The multi-joint robot system according to Claim 1, characterized by the above.

3. The first moving mechanism is disposed inside the first link, and the second moving mechanism is disposed inside the second link. The multi-joint robot system according to Claim 1, characterized by the above.

4. The multi-joint robot further includes a second driving mechanism for rotating at least a part of the base about a second axis at an angle less than or equal to the predetermined angle with respect to a direction perpendicular to the bottom surface of the base, a third driving mechanism for rotating the first link about a third axis at an angle greater than the predetermined angle with respect to a direction perpendicular to the bottom surface of the base and connecting the base and the first link, and a fourth driving mechanism for connecting the second link and the tip and rotating the tip relative to the second link. The control device operates the articulated robot by controlling the operations of the first drive mechanism, the second drive mechanism, the first movement mechanism, the second movement mechanism, the third drive mechanism, and the fourth drive mechanism. The articulated robot system according to any one of claims 1 to 3, characterized in that.

5. The fourth drive mechanism rotates the tip portion with respect to the second link using an axis that forms an angle greater than the predetermined angle with the second direction as a fourth rotation axis. The tip portion includes a first portion connected to the second link, a second portion connected to the first portion, and a fifth drive mechanism that connects the first portion and the second portion and rotates the second portion with respect to the first portion using an axis that forms an angle greater than the predetermined angle with the fourth rotation axis as a fifth rotation axis, and a sixth drive mechanism that rotates a portion of the tip portion to which the end effector is attached using an axis that forms an angle greater than the predetermined angle with the fifth rotation axis as a sixth rotation axis. The control device operates the articulated robot by controlling the operations of the first drive mechanism, the second drive mechanism, the first movement mechanism, the second movement mechanism, the third drive mechanism, the fourth drive mechanism, the fifth drive mechanism, and the sixth drive mechanism. The articulated robot system according to claim 4, characterized in that.

6. The fourth drive mechanism rotates the tip portion with respect to the second link using an axis that forms an angle less than or equal to the predetermined angle with the second direction as a fourth rotation axis. The tip portion includes a first portion connected to the second link, a second portion connected to the first portion, and a fifth drive mechanism that connects the first portion and the second portion and rotates the second portion with respect to the first portion using an axis that forms an angle greater than the predetermined angle with the fourth rotation axis as a fifth rotation axis, and a sixth drive mechanism that rotates a portion of the tip portion to which the end effector is attached using an axis that forms an angle greater than the predetermined angle with the fifth rotation axis as a sixth rotation axis. The control device operates the articulated robot by controlling the operations of the first drive mechanism, the second drive mechanism, the first movement mechanism, the second movement mechanism, the third drive mechanism, the fourth drive mechanism, the fifth drive mechanism, and the sixth drive mechanism. The articulated robot system according to claim 4, characterized in that.

7. The articulated robot further includes a first motor that drives the first drive mechanism and moves together with the first drive mechanism, a second motor provided on the first link that drives the first moving mechanism, a third motor provided on the second link that drives the second moving mechanism and moves together with the second link as the second link moves relative to the first link, and a second drive mechanism that rotates at least a part of the base with an axis that forms an angle of not more than the predetermined angle with a direction perpendicular to the bottom surface of the base as a second rotation axis. The control device drives the first drive mechanism by controlling the first motor, rotates the second link relative to the first link, drives the first moving mechanism by controlling the second motor, relatively moves the first drive mechanism relative to the first link along the first direction, drives the second drive mechanism by controlling the third motor, and relatively moves the second link relative to the first link along the second direction. The articulated robot system according to any one of claims 1 to 3, characterized in that.

8. A method for controlling an articulated robot having a base, a tip, a first link, and a second link, and a plurality of links connecting the base and the tip, By controlling the operation of a first drive mechanism that connects the first link and the second link and rotates the second link relative to the first link with an axis that forms an angle greater than a predetermined angle with a first direction in which the first link extends as a first rotation axis, the operation of a first moving mechanism that relatively moves the first drive mechanism relative to the first link along the first direction, and the operation of a second moving mechanism that relatively moves the second link relative to the first drive mechanism along a second direction in which the second link extends, the articulated robot is operated. A method for controlling an articulated robot, characterized in that.

9. The first drive mechanism is disposed inside the first link and includes a portion that moves along the first direction within the length range of the first link and a portion that is connected to the second link and moves along the second direction within the length range of the second link. By moving the first drive mechanism relative to the second link along the second direction within the range of the length of the second link, the second link is moved relative to the first link along the second direction. The method for controlling a multi-joint robot according to claim 8, characterized in that.

10. The first moving mechanism is disposed inside the first link, and the second moving mechanism is disposed inside the second link. The method for controlling a multi-joint robot according to claim 8, characterized in that.

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