Robot and robot system

Abstract

To provide a robot and a robot system which can improve accuracy in detecting vibration.SOLUTION: The robot is provided with: a base that is installed on an installation surface; a first arm that is connected to the base to be turnable around a first turning shaft with respect to the base; a second arm that is connected to the first arm to be turnable around a second turning shaft that is parallel to the first turning shaft with respect to the first arm; a shaft having an end part at the first arm side thereof, which is connected to the second arm to be turnable around a third turning shaft that is parallel to the first turning shaft with respect to the second arm and to be movable along a shaft direction of the third turning shaft; and a vibration detecting part provided in the base, where a length of the shaft from the second arm to an end part of the shaft is shorter than a distance along the shaft direction of the third turning shaft between the second arm and the first arm.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a robot and a robot system. [Background technology]

[0002] 2. Description of the Related Art As one type of industrial robot, for example, a ceiling-suspended SCARA robot that is suspended from a ceiling surface as described in Patent Document 1 is known.

[0003] The ceiling-mounted SCARA robot described in Patent Document 1 has a base (base platform) fixed to the ceiling, a first arm connected to the base and rotatable in a horizontal plane, a second arm connected to the first arm and rotatable in a horizontal plane, and an operating shaft provided at the tip of the second arm and on which a tool for carrying a workpiece (component) or the like is attached. A motor and a reducer for driving the operating shaft are fixed to the second arm. The first arm and the second arm form a robot arm.

[0004] In such ceiling-mounted scalar robots, an acceleration sensor is installed at the tip of the robot arm as a vibration detector, and vibration damping control is sometimes performed to suppress vibrations of the robot based on the detection value detected by this acceleration sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2012 / 029174 publication Summary of the Invention [Problem to be solved by the invention]

[0006] The ceiling-mounted SCARA robot described in Patent Document 1 is installed on the ceiling of a base, so in order to accurately detect the vibrations of the robot and the base, it is necessary to install a vibration detector in an appropriate location. However, in the past, sufficient thought was not given to the installation position of the vibration detector, resulting in insufficient vibration detection accuracy. [Means for solving the problem]

[0007] The robot of the present invention comprises: a base that is installed on an installation surface; a first arm connected to the base so as to be rotatable about a first rotation axis relative to the base; a second arm connected to the first arm so as to be rotatable about a second rotation axis parallel to the first rotation axis with respect to the first arm; a shaft connected to the second arm so as to be rotatable about a third rotation axis parallel to the first rotation axis with respect to the second arm and movable along an axial direction of the third rotation axis, the shaft having an end on the first arm side; A vibration detection unit provided on the base, The length of the shaft from the second arm to the end of the shaft is less than the distance along the axial direction of the third pivot axis between the second arm and the first arm.

[0008] The robot system of the present invention includes: a base that is installed on an installation surface; a first arm connected to the base so as to be rotatable about a first rotation axis relative to the base; a second arm connected to the first arm so as to be rotatable about a second rotation axis parallel to the first rotation axis with respect to the first arm; a shaft connected to the second arm and having an end on the first arm side, the shaft being rotatable about a third rotation axis parallel to the first rotation axis with respect to the second arm and movable along an axial direction of the third rotation axis; A vibration detection unit provided on the base; a control unit that controls driving of at least one of the first arm, the second arm, and the shaft based on a detection value of the vibration detection unit, The length of the shaft from the second arm to the end of the shaft is less than the distance along the axial direction of the third pivot axis between the second arm and the first arm. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of a first embodiment of a robot and a robot system according to the present invention. [Diagram 2] FIG. 2 is a partially enlarged cross-sectional view of the robot shown in FIG. [Diagram 3] FIG. 3 is a block diagram of the robot system shown in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the base and the vibration detection unit shown in FIG. [Diagram 5] FIG. 5 is a partial cross-sectional view of a base and a vibration detection unit provided in a robot and a robot system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A robot and a robot system according to the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0011] First Embodiment Fig. 1 is a side view of a first embodiment of a robot and a robot system according to the present invention. Fig. 2 is a partially enlarged cross-sectional view of the robot shown in Fig. 1. Fig. 3 is a block diagram of the robot system shown in Fig. 1. Fig. 4 is an enlarged cross-sectional view of a base and a vibration detection unit shown in Fig. 1.

[0012] For ease of explanation, the upper side in Figures 1 and 2 will be referred to as "upper", the lower side as "lower", the left side as "left", and the right side as "right". Furthermore, the up-down direction in Figures 1 and 2 will be referred to as the "vertical direction", and the left-right direction as the "horizontal direction".

[0013] As shown in FIG. 1, the robot system 100 includes a robot 1 and a control device 7 that controls the robot 1.

[0014] The robot 1 shown in Fig. 1 is a horizontal articulated robot that is suspended from the ceiling, and is a so-called ceiling-suspended SCARA robot. Fig. 1 shows the basic posture of the robot 1.

[0015] The robot 1 is used in, for example, a manufacturing process for manufacturing precision devices such as mobile phones, smartphones, and tablet terminals, and can grasp, transport, process, assemble, and the like, precision devices and parts.

[0016] In this embodiment, the robot 1 is installed by being suspended from a top plate 91 serving as a ceiling located on the top of a stand 9 having frame-shaped legs 92. The top plate 91 is installed horizontally, and has an upper surface 911 and a lower surface 912. At least one of the surfaces of the top plate 91 serves as an installation surface on which the robot 1 is installed. In this embodiment, the lower surface 912 is the installation surface on which the robot 1 is installed.

[0017] The top plate 91 has through holes 913, 914 penetrating it in the thickness direction. The through holes 913, 914 are arranged spaced apart from each other in this order from the left side in Fig. 1. The through hole 913 is a window through which an operator can access the top plate 91 from above when performing maintenance on the second motor unit 50, which will be described later, and the like. The through hole 914 is a hole for installing the base 11 on the top plate 91, and the base 11 is inserted through it.

[0018] 1, the robot 1 has a base 11 and a robot arm 10 connected to the base 11. The robot arm 10 has a first arm 20 that is driven to rotate with respect to the base 11, a second arm 40 that is driven to rotate with respect to the first arm 20, and a work head 60, and the rotational driving of the first arm 20 and the second arm 40 is controlled by a control device 7 described later.

[0019] Each component of the robot 1 will now be described in detail. As shown in FIG. 1, the base 11 is a member located at the top of the robot 1 and attached to the top plate 91 of the stand 9. The base 11 has a main body 110 and a plate-shaped flange 111 provided at the bottom of the main body 110. The main body 110 is inserted into a through hole 914 and is configured as a housing. The flange 111 functions as a mounting part for mounting the base 11 to the bottom surface 912 by being fixed to the bottom surface 912 via a fixing member 112 such as a bolt, a screw, or a pin. The method of fixing the base 11 to the bottom surface 912 is not limited to the above-mentioned method of fixing using the fixing member 112, and may be any method such as a method of fixing using adhesive.

[0020] In the illustrated configuration, the base 11 is attached to the lower surface 912 by the flange portion 111, but the present invention is not limited to this. For example, the upper part of the base 11 may be attached to the lower surface 912.

[0021] Moreover, the base 11 may be configured to be attached to the upper surface 911 of the top board 91. In this case, the upper surface 911 is an installation surface of the robot 1. When the base 11 is configured to be attached to the upper surface 911 of the top board 91, for example, the lower surface of the flange portion 111 can be fixed to the upper surface 911, and a first joint portion 29, which will be described later, can be inserted through a through hole 914.

[0022] [Robot arm] As shown in FIG. 1, the robot arm 10 has a first arm 20 extending horizontally, a first motor unit 30 partially provided within a base 11 and configured to rotate the first arm 20, a second arm 40 provided below the first arm 20 and configured to be L-shaped in a side view, and a second motor unit 50 partially provided on the first arm 20 and configured to rotate the second arm 40.

[0023] A first joint 29 is provided at one end of the first arm 20, i.e., the end on the right side in FIG. 1, and the first arm 20 is supported at one end by the base 11 via the first joint 29. The first joint 29 is a connection part that rotatably connects the first arm 20 to the base 11. The first joint 29 includes a part of a reducer 33, which will be described later, a shaft 34, and a hollow plate 291. As a result, the first arm 20 is connected to the base 11 so as to be rotatable about a first rotation axis J1 that extends along the vertical direction.

[0024] The first motor unit 30 has a first motor 31 as a first driving source, a belt 32, a reducer 33, and a shaft 34. At least a part of the first motor unit 30 is housed in the main body 110, so that intrusion of foreign matter such as dust and dirt into the first motor unit 30 and discharge of foreign matter from the first motor unit 30 to the outside of the robot arm 10 are prevented. The first motor 31 and the belt 32 are housed in the main body 110 of the base 11. In this embodiment, the pulley 331 and a part of the input shaft of the reducer main body 332 of the reducer 33 are provided in the main body 110 of the base 11, and the remaining part of the input shaft of the reducer main body 332, the reduction unit, and the output shaft are outside the main body 110 of the base 11. Note that the entire reducer 33 may be provided in the main body 110 of the base 11. The reducer 33 is a hollow reducer, and includes a pulley 331 around which the belt 32 is wound, and a reducer body 332. The reducer body 332 includes an input shaft connected to the pulley 331, a reduction unit that reduces the rotational force of the input shaft, and an output shaft that outputs the reduced rotational force. The input shaft and the output shaft of the reducer body 332 are coaxially arranged. In this embodiment, the reducer body 332 is a wave gear reducer. The output shaft of the reducer body 332 is fixed to the plate 291.

[0025] A shaft 34 is disposed in the hollow center of the reducer 33 and the plate 291. The shaft 34 is hollow and extends vertically, and its lower end is fixed to the first arm 20. Wires, piping, and the like (not shown) are routed between the base 11 and the first arm 20 through this hollow shaft 34. The plate 291 connects the reducer body 332 and the first arm 20. In this embodiment, the plate 291 is recessed around the shaft 34, and a bearing supporting the input shaft of the reducer body 332 is disposed in this recess. In addition, the output shaft of the reducer body 332 and the first arm 20 are fixed to a portion of the plate 291 that is located on the outer diameter side of the recess. In such a first motor unit 30, the rotational driving force of the first motor 31 is transmitted to the reducer 33 via the belt 32 and is reduced in speed by the reducer 33, and the plate 291 rotates due to the increased rotational force, and the rotation of the plate 291 rotates the first arm 20. Note that in this embodiment, the shaft 34 is disposed in the reducer 33 and the plate 291, but this is not limiting, and a structure in which the shaft 34 is not disposed in the reducer 33 and the plate 291 may also be used. In that case, the reducer 33 and the plate 291 do not need to be hollow, and wiring, piping, etc. may be routed outside.

[0026] A second joint 49 is provided at the upper end of the second arm 40, and the second arm 40 is connected to the other end of the first arm 20, i.e., the end on the left side in FIG. 1, via the second joint 49. The second joint 49 includes a part of a reducer 53, which will be described later, a shaft 54, and a hollow plate 491. The second arm 40 has a first member 41 extending vertically downward from the second joint 49, and a second member 42 extending horizontally from a lower end of the first member 41. The first member 41 is also called a columnar portion, and the second member 42 is also called an arm base.

[0027] The first member 41 and the second member 42 are either integrally formed or formed by fixing separate members. The second joint portion 49 has a mechanism for supporting the second arm 40 rotatably relative to the first arm 20. This allows the second arm 40 to rotate relative to the first arm 20 about a second rotation axis J2 that extends in the vertical direction.

[0028] The second rotation shaft J2 and the first rotation shaft J1 are spaced apart in the horizontal direction by a predetermined distance, for example, a distance of 50 mm or more and 900 mm or less.

[0029] The second motor unit 50 is provided on the first arm 20 and includes a second motor 51 as a second driving source, a belt 52, a reducer 53, and a shaft 54. At least a part of the second motor unit 50 is housed in the first arm 20, so that foreign matter such as dust and dirt is prevented from entering the second motor unit 50 and from being discharged from the second motor unit 50 to the outside of the robot arm 10. The second motor 51 and the belt 52 are housed in the first arm 20. In this embodiment, the pulley 531 and a part of the input shaft of the reducer body 532 of the reducer 53 are provided in the first arm 20, and the remaining part of the input shaft of the reducer body 532, the reduction unit, and the output shaft are outside the first arm 20. Note that the entire reducer 53 may be provided in the first arm 20.

[0030] The reducer 53 is a hollow reducer, and includes a pulley 531 around which the belt 52 is wound, and a reducer body 532. The reducer body 532 includes an input shaft connected to the pulley 531, a reduction unit that reduces the rotational force of the input shaft, and an output shaft that outputs the rotational force after reduction. The input shaft and the output shaft of the reducer body 532 are coaxially arranged. In this embodiment, the reducer body 532 is a wave gear reducer. The output shaft of the reducer body 532 is fixed to the plate 491. A shaft 54 ​​is arranged in the hollow center of the reducer 53 and the plate 491. The shaft 54 ​​is hollow, extends along the vertical direction, and has a lower end fixed to the second arm 40. Wiring, piping, etc. (not shown) are routed between the first arm 20 and the second arm 40 through this hollow shaft 54. The plate 491 connects the reduction gear body 532 and the second arm 40. In this embodiment, the plate 491 is recessed around the shaft 54, and a bearing that supports the input shaft of the reduction gear body 532 is disposed in this recess. In addition, the output shaft of the reduction gear body 532 and the second arm 40 are fixed to a portion of the plate 491 that is located on the outer diameter side of the recess.

[0031] An upper portion of the second motor unit 50 is covered by a cover member 55 provided on the first arm 20. This prevents foreign matter such as dust and dirt from entering the second motor unit 50.

[0032] In such a second motor unit 50, the driving force of the second motor 51 is transmitted to the reducer 53 via the belt 52 and is reduced in speed by the reducer 53, causing the plate 491 to rotate due to the increased rotational force, and the rotation of the plate 491 rotates the second arm 40. Note that in this embodiment, the shaft 54 ​​is disposed in the reducer 53 and the plate 491, but this is not limiting, and a structure in which the shaft 54 ​​is not disposed in the reducer 53 and the plate 491 may also be used. In that case, the reducer 53 and the plate 491 do not need to be hollow, and wiring, piping, and the like may be routed outside.

[0033] In the robot arm 10 configured as above, the first rotation axis J1 of the first arm 20 and the second rotation axis J2 of the second arm 40 are parallel to each other, but are offset from each other in the horizontal direction. That is, the first rotation axis J1 and the second rotation axis J2 are spaced apart from each other by a predetermined distance in the horizontal direction. This allows the robot arm 10 to have a wide movable range.

[0034] [Working head] 1 and 2, the working head 60 has an operating shaft 61, which is a shaft provided at the tip of the second arm 40, and a drive unit 65 provided on the second member 42 between the operating shaft 61 and the first member 41. In addition, the operating shaft 61 and a part of the drive unit 65 are covered by a cover member 62 provided on the second member 42 of the second arm 40, thereby preventing the intrusion of foreign matter such as dust and dirt. Note that the cover member 62 is detachable from the second member 42, but may be fixed to the second member 42.

[0035] The actuating shaft 61 is provided along a third rotation axis J3 extending in the vertical direction, and can move along the third rotation axis J3 and rotate about the third rotation axis J3. The movement and rotation drive of the actuating shaft 61 along the third rotation axis J3 are controlled by a control device 7, which will be described later. The actuating shaft 61 has an upper end 610 which is the end on the first arm 20 side, and a lower end 611 which is the end opposite to the first arm 20. The lower end 611 of the actuating shaft 61 protrudes downward from the second arm 40. As shown in FIG. 1, an end effector such as a hand 90 for gripping a precision instrument or a part is detachably attached to the protruding lower end 611 of the actuating shaft 61.

[0036] The upper end 610 of the actuating shaft 61 can move upward from the second member 42 of the second arm 40 along the third rotation axis J3. As shown in FIG. 2, the upper end 610 of the actuating shaft 61 is located inside the cover member 62 and is not allowed to move upward beyond the cover member 62. That is, the upper limit of the movement of the upper end 610 is below the first arm 20. That is, the length l1 of the actuating shaft 61 along the axial direction of the third rotation axis J3 from the second member 42 of the second arm 40 to the upper end 610 is shorter than the distance D along the axial direction of the third rotation axis J3 between the second member 42 of the second arm 40 and the first arm 20. At this time, the upper end 610 of the actuating shaft 61 and the first arm 20 are separated by a predetermined distance d1 along the axial direction of the third rotation axis J3. As a result, even when the actuating shaft 61 is raised to the maximum, the second arm 40 can pass under the first arm 20 without interfering with the actuating shaft 61. That is, the second arm 40 can rotate 360° relative to the first arm 20 regardless of the vertical position of the operating shaft 61. Also, the length l2 of the cover member 62 along the axial direction of the third rotation shaft J3 from the second member 42 of the second arm 40 to the upper end of the cover member 62, which is the end of the cover member 62 on the first arm 20 side, is longer than the above-mentioned length l1, but is shorter than the distance D, similarly to the above-mentioned length l1. That is, the upper end of the cover member 62 and the first arm 20 are separated by a predetermined distance d2 along the axial direction of the third rotation shaft J3. In this case, the second arm 40 can pass under the first arm 20 without the cover member 62 interfering with the first arm 20, as in the above case. The distance D along the axial direction of the third rotation shaft J3 between the second member 42 of the second arm 40 and the first arm 20 is the distance between the second member 42 of the second arm 40 and the first arm 20 on the axis line of the third rotation shaft J3, and the distance between the second member 42 of the second arm 40 and the first arm 20 other than on the axis line of the third rotation shaft J3 may be shorter than the above-mentioned lengths l1 and l2. Also, at least a part of the first member 41 and the first arm 20 may be integral with each other.In this case, the second joint portion 49 is positioned between the first member 41 integral with the first arm 20 and the second member 42 of the second arm 40, or between a part of the first member 41 integral with the first arm 20 and the remaining part of the first member 41 of the second arm 40.

[0037] As shown in FIG. 2, the drive unit 65 has a shaft lifting mechanism 66 that lifts and lowers the operating shaft 61, and a shaft rotating mechanism 67 that rotates the operating shaft 61.

[0038] The shaft lifting mechanism 66 has a shaft lifting motor 661, a lead screw mechanism 662, and a belt 663. The lead screw mechanism 662 is composed of a ball screw having a screw groove (not shown) formed on the outer circumferential surface of the operating shaft 61 and a female screw block 6621 rotatably supported on the upper part of the second member 42. In such a shaft lifting mechanism 66, the driving force of the shaft lifting motor 661 is transmitted to the female screw block 6621 via the belt 663, which rotates the female screw block 6621 to lift the operating shaft 61 up and down (vertical direction).

[0039] The shaft rotating mechanism 67 has a shaft rotating motor 671, a spline mechanism 672, and a belt 673. The spline mechanism 672 is configured with a ball spline having a spline groove (not shown) formed on the outer circumferential surface of the working shaft 61 and a boss block 6721 rotatably supported on the lower part of the second member 42. The spline mechanism 672 supports the working shaft 61 so as to be slidable in the vertical direction. In such a shaft rotating mechanism 67, the driving force of the shaft rotating motor 671 is transmitted to the boss block 6721 via the belt 673, and the boss block 6721 rotates to rotate the working shaft 61.

[0040] Each of the first motor 31, the second motor 51, the shaft lifting motor 661, and the shaft rotating motor 671 has an encoder. As shown in Fig. 3, each of the first motor 31, the second motor 51, the shaft lifting motor 661, and the shaft rotating motor 671 is electrically connected to the control device 7 via, for example, wiring or the like (not shown).

[0041] Next, the control device 7 will be described. 1, in this embodiment, the control device 7 is installed at a position separate from the robot 1. However, the present invention is not limited to this configuration, and the control device 7 may be built into the base 11. The control device 7 also has a function of controlling the driving of the robot 1, and is electrically connected to each part of the robot 1 described above.

[0042] 3, the control device 7 includes a control unit 71, a storage unit 72, and a communication unit 73. These units are connected to each other so as to be able to communicate with each other via a bus, for example.

[0043] The control unit 71 is composed of, for example, at least one CPU (Central Processing Unit), and reads and executes various programs such as operation programs stored in the storage unit 72. Signals generated by the control unit 71 are transmitted to each part of the robot 1 via the communication unit 73, and signals from each part of the robot 1 are received by the control unit 71 via the communication unit 73. This enables the robot arm 10 to perform a predetermined task under predetermined conditions.

[0044] The control unit 71 also has a position command generation unit, a motor control unit, and multiple motor drivers. The motor control unit performs noise processing, coordinate conversion processing, and the like on the output value of an inertial sensor 81 (described later) and calculates the magnitude and direction of vibration detected by the inertial sensor 81. Then, it generates a feedback value that cancels the vibration component, and uses this feedback value to control each motor of the robot arm 10.

[0045] Specifically, the position command generating unit calculates a target position of the operating shaft 61 based on the contents of the processing performed by the robot 1, and generates a trajectory for moving the operating shaft 61 to the calculated target position. The position command generating unit also calculates the rotation angles of the motors 31, 51, 661, 671 for each predetermined control period so that the operating shaft 61 moves along the generated trajectory, and outputs the target rotation angles resulting from the calculation to the motor control unit as each position command.

[0046] The motor control unit receives position commands for the motors 31, 51, 661, and 671 and detection signals from the encoders, performs feedback control so that the rotation angles of the motors 31, 51, 661, and 671 match target rotation angles, and outputs control signals to the motor drivers. When driving at least some of the motors, the motor control unit also receives a detection signal from the inertial sensor 81. The motor control unit receives a detection signal from the inertial sensor 81, and uses the detection signals from at least some of the encoders and the detection signal from the inertial sensor 81 to calculate a feedback value that cancels the vibration component, and performs the above-mentioned feedback control.

[0047] A motor driver is provided for each of the motors 31, 51, 661, 671, and operates based on a control signal from the motor control unit. Each of the motor drivers has an inverter circuit including a switching element, converts DC current to AC current by PWM control, and supplies the AC current to each of the motors 31, 51, 661, 671 to drive each of the motors 31, 51, 661, 671.

[0048] In this embodiment, for example, the driving of the first motor 31 will be described. In addition to the position command of the first motor 31, the motor control unit receives detection signals from the encoder of the first motor 31, the encoder of the second motor 51, and the inertial sensor 81, and calculates a feedback value using these detection signals. The motor control unit performs feedback control using the feedback value so that the rotation angle of the first motor 31 calculated from the detection signal of the encoder of the first motor 31 matches the target rotation angle of the first motor 31, and outputs a control signal to the motor driver of the first motor 31. The motor driver of the first motor 31 supplies an AC current to the first motor 31 based on the control signal of the motor control unit to drive the first motor 31. By driving each motor of the robot arm 10 using such feedback values, it is possible to perform vibration suppression control on the first arm 20, the second arm 40, and the work head 60 based on the detection value of the vibration detection unit 8, as described later. Note that only one motor control unit is provided in the control unit 71, but this is not limited thereto, and multiple motor control units may be provided. When a plurality of motor control units are provided, they may be motor control units corresponding to the respective motors 31, 51, 661, 671. Also, a configuration may be adopted in which the detection signal of the encoder of the second motor 51 is not input to the motor control unit when driving the first motor 31. In this case, the motor control unit calculates a feedback value using the detection signals from the encoder of the first motor 31 and the inertial sensor 81.

[0049] However, this configuration is not limited to this, and the control unit 71 can be configured to perform vibration control on one or any combination of two or more of the first arm 20, the second arm 40, and the work head 60 based on the detection value of the vibration detection unit 8.

[0050] For example, the control unit 71 may be configured to perform vibration suppression control only on the first arm 20 based on the detection value of the vibration detection unit 8. In other words, the feedback value may be used to drive only the first motor 31.

[0051] Furthermore, the control unit 71 may be configured to perform vibration suppression control only on the second arm 40 based on the detection value of the vibration detection unit 8. In other words, the feedback value may be used to drive only the second motor 51.

[0052] Furthermore, the control unit 71 may be configured to perform vibration suppression control only on the working head 60 based on the detection value of the vibration detection unit 8. That is, the feedback value may be used to drive only the shaft lift motor 661 and the shaft rotation motor 671 of the drive unit 65. Furthermore, when performing vibration suppression control on the working head 60, the feedback value may be used to drive only one of the shaft lift motor 661 and the shaft rotation motor 671. This also applies to the following description.

[0053] Furthermore, the control unit 71 may be configured to perform vibration suppression control only on the first arm 20 and the second arm 40 based on the detection value of the vibration detection unit 8. In other words, the feedback value may be used to drive only the first motor 31 and the second motor 51.

[0054] Furthermore, the control unit 71 may be configured to perform vibration suppression control only on the first arm 20 and the working head 60 based on the detection value of the vibration detection unit 8. In other words, the feedback value may be used to drive only the first motor 31, the shaft lifting motor 661, and the shaft rotating motor 671.

[0055] Furthermore, the control unit 71 may be configured to perform vibration suppression control only on the second arm 40 and the working head 60 based on the detection value of the vibration detection unit 8. In other words, the feedback value may be used to drive only the second motor 51, the shaft lifting motor 661, and the shaft rotating motor 671.

[0056] In the suspended robot 1, the above-mentioned vibration control can be performed to improve the positional accuracy of the work and perform the work with high accuracy. In particular, as described later, the robot system 100 can accurately detect the vibration of the base 11, so that the work can be performed with higher accuracy.

[0057] The storage unit 72 stores various programs and the like executed by the control unit 71. Examples of the storage unit 72 include a configuration having a volatile memory such as a RAM (Random Access Memory), a non-volatile memory such as a ROM (Read Only Memory), a removable external storage device, and the like.

[0058] The communication unit 73 transmits and receives signals between each part of the robot 1 and the control device 7 using an external interface such as a wired LAN (Local Area Network) or a wireless LAN. In this case, communication may be performed via a server (not shown), or via a network such as the Internet.

[0059] Next, the vibration detection unit 8 will be described. The vibration detection unit 8 shown in FIG. 1 is installed on the base 11 and detects vibration. When the base 11 vibrates, each part of the robot arm 10 vibrates as the robot arm 10 is driven, and the vibration is transmitted to the top plate 91, causing the top plate 91 to vibrate significantly. This vibration of the top plate 91 may have a negative effect on the accuracy of the work. For example, the top plate 91 receives a force from the robot arm 10 in a direction perpendicular to the first rotation axis J1, that is, in the horizontal direction in this embodiment, due to the rotation of the first arm 20 around the first rotation axis J1, the rotation of the second arm 40 around the second rotation axis J2, or the rotation of the operating shaft 61 around the third rotation axis J3, and vibrates. In addition, at least a part of the top plate 91 receives a force from the robot arm 10 in the axial direction of the first rotation axis J1, that is, in the vertical direction in this embodiment, due to the movement of the operating shaft 61 along the third rotation axis J3, or the gripping or releasing of the workpiece by the hand 90, and vibrates. In particular, in the frame-shaped stand 9, the vibration of the top plate 91 is difficult to attenuate. Therefore, the vibration of the top plate 91 then vibrates the robot arm 10 through the base 11 installed on the top plate 91, and as a result, the position of the operating axis 61 deviates from the target position. For this reason, when driving a ceiling-suspended SCARA robot suspended from a ceiling to perform work, it is preferable to perform vibration suppression control, that is, drive control according to the content, characteristics, degree, etc. of the vibration, for at least some of the motors so that the operating axis 61 is at the target position. In order to perform the vibration suppression control as described above, it is necessary to accurately detect the vibration of the top plate 91. Therefore, in the present invention, the vibration detection unit 8 is installed on the base 11 fixed to the top plate 91 of the stand 9. This allows the vibration of the top plate 91 to be detected more directly, so that the detection accuracy of the vibration can be improved. As a result, for example, the vibration suppression control as described above can be performed appropriately, and the work accuracy can be improved. In addition, the work of installing or removing the vibration detection unit 8 can be time-consuming for the worker, and the difficulty of the work increases especially when the top plate 91 is located at a high position. In the present invention, since the vibration detection unit 8 is installed on the base 11, the work of installing or removing the vibration detection unit 8 can be omitted compared to when the robot arm 10 and the vibration detection unit 8 are installed or removed separately on the top board 91.

[0060] In particular, in the robot arm 10, the second arm 40 can rotate 360° relative to the first arm 20. In this configuration, if a vibration detection unit 8 is provided at the tip of the robot arm 10 as in the conventional case, complex calculations are required to identify the vibration direction. In contrast, according to the configuration of the present invention, the vibration direction can be easily identified, which is advantageous compared to the conventional case.

[0061] Furthermore, in the illustrated ceiling-mounted robot, the distance between the installation surface (lower surface 912 in this embodiment) of the robot and the ground (not shown) is greater than in a SCARA robot that is installed on the ground (not shown). Therefore, the tip of the robot arm 10 is more susceptible to vibrations. In light of these factors, the configuration of the present invention has the distinct advantage of being able to accurately detect vibrations.

[0062] 4, in this embodiment, the vibration detection unit 8 is configured with an inertial sensor 81 that detects the inertial force of the base 11. In this embodiment, the inertial sensor 81 includes a total of six types of acceleration, including acceleration along the x-axis, acceleration along the y-axis, acceleration along the z-axis, angular velocity around the x-axis, angular velocity around the y-axis, and angular velocity around the z-axis. That is, the inertial sensor 81 is an IMU (Inertial Measurement Unit) that detects acceleration in three mutually orthogonal axial directions and angular velocity around the three axes.

[0063] However, without being limited to this configuration, the inertial sensor 81 may be configured to detect, for example, only acceleration along the x-axis, acceleration along the y-axis, and acceleration along the z-axis, or may be configured to detect only angular velocity around the x-axis, angular velocity around the y-axis, and angular velocity around the z-axis.

[0064] In addition to these, the inertial sensor 81 may be configured to detect angular acceleration around the x-axis, angular acceleration around the y-axis, and angular acceleration around the z-axis, or may be configured to detect only angular acceleration around the x-axis, angular acceleration around the y-axis, and angular acceleration around the z-axis.

[0065] As shown in FIG. 3, the inertial sensor 81 is electrically connected to the control device 7, and the detection value detected by the inertial sensor 81 is transmitted to the control device 7 as an electric signal and used for the vibration damping control described above.

[0066] The vibration detection unit 8 is not limited to the above configuration, and may be, for example, a contact or non-contact vibration sensor. A pressure-sensitive sensor or the like can be used as a contact vibration sensor. An electrodynamic, servo, strain gauge, eddy current, capacitance, ultrasonic, optical sensor or the like can be used as a non-contact vibration sensor.

[0067] Furthermore, the vibration detection unit 8 may be equipped with a display, a memory, etc. Furthermore, the vibration detection unit 8 may be configured to wirelessly transmit the detection value to an external device.

[0068] Moreover, the inertial sensor 81 is installed on the flange portion 111. As a result, the inertial sensor 81 is disposed on the flange portion 111 which is directly fixed to the top plate 91, and therefore the vibration of the base 11 received from the top plate 91 can be detected more directly.

[0069] As shown in Fig. 4, the base 11 has a recess 114 that opens to the lower surface 113 side of the flange portion 111. The recess 114 has a bottom surface 115 and an inner side surface 116. The inertial sensor 81 is provided in the recess 114. This makes it possible to sufficiently detect vibrations of the base 11 while protecting the inertial sensor 81. The depth of the recess 114 is deep enough to sufficiently accommodate the inertial sensor 81. This makes it possible to more reliably protect the inertial sensor 81.

[0070] Moreover, the inertial sensor 81 is disposed on the bottom surface 115 of the recess 114. This makes it possible to efficiently detect the vibration of the base 11 while more reliably protecting the inertial sensor 81. Note that the inertial sensor 81 may be disposed on the inner surface 116.

[0071] 1, the recess 114 is disposed offset from the first motor 31 when viewed in the direction of the first rotation axis J1, i.e., the vertical direction. In other words, the recess 114 and the first motor 31 do not overlap when viewed in the vertical direction. Therefore, the first motor 31 and the inertial sensor 81 (vibration detection unit 8) are disposed offset from each other when viewed in the vertical direction. This makes it possible to easily perform maintenance such as cleaning, inspection, repair, and replacement of the first motor 31, and also to easily perform maintenance of the inertial sensor 81.

[0072] The first motor 31 and the inertial sensor 81 may partially overlap when viewed in the vertical direction.

[0073] Furthermore, the recess 114 is disposed so as to be offset from the first joint portion 29 when viewed in the direction of the first rotation axis J1, i.e., the vertical direction. In other words, the recess 114 and the first joint portion 29 do not overlap when viewed in the vertical direction. Therefore, the first joint portion 29 and the inertial sensor 81 are disposed so as to be offset from each other when viewed in the vertical direction. This makes it possible to easily perform maintenance of the first joint portion 29 and also to easily perform maintenance of the inertial sensor 81.

[0074] The first joint portion 29 and the inertial sensor 81 may partially overlap when viewed from the vertical direction.

[0075] In this embodiment, in the basic posture of the robot 1 shown in Figure 1, the inertial sensor 81 (vibration detection unit 8) is positioned offset from the second motor 51, which is the second driving source, when viewed from the vertical direction, and is also positioned offset from the second joint unit 49.

[0076] Also, unlike the configuration shown in the drawings, recess 114 may be formed to open on the upper surface or side surface of flange portion 111, or may be formed as a through hole penetrating flange portion 111 in the thickness direction. Furthermore, recess 114 may be provided in a portion of base 11 other than flange portion 111, for example, in main body portion 110.

[0077] Furthermore, the inertial sensor 81 (vibration detection unit 8) may be installed in the center of the base 11 when viewed from the vertical direction. Since the center of the base 11 is a part that is relatively prone to vibrate, particularly in the up-down direction, the vibration detection accuracy can be improved.

[0078] As described above, the robot 1 includes the base 11 installed on the underside 912, which is the installation surface of the top board 91, the first arm 20 connected to the base 11 so as to be rotatable around the first rotation axis J1 relative to the base 11, the second arm 40 connected to the first arm 20 so as to be rotatable around the second rotation axis J2 parallel to the first rotation axis J1 relative to the first arm 20, the operating shaft 61 as a shaft connected to the second arm 40 so as to be rotatable around the third rotation axis J3 parallel to the first rotation axis J1 relative to the second arm 40 and movable along the axial direction of the third rotation axis J3, the operating shaft 61 having an upper end 610 which is an end on the first arm 20 side, and a vibration detection unit 8 provided on the base 11, and the length l1 of the operating shaft 61 from the second arm 40 to the upper end 610 of the operating shaft 61 is shorter than the distance D along the axial direction of the third rotation axis J3 between the second arm 40 and the first arm 20. This allows the vibration detection unit 8 to more directly detect the vibration of the tabletop 91, thereby improving the vibration detection accuracy. As a result, for example, vibration suppression control can be performed more appropriately, and work accuracy can be improved.

[0079] As described above, the base 11 has the flange portion 111 fixed to the underside 912, which is the installation surface of the top board 91, and the vibration detection unit 8 is provided on the flange portion 111. This allows the vibration of the base 11 to be detected more directly, which contributes to improving the vibration detection accuracy.

[0080] It should be noted that the present invention is not limited to the configuration shown in the figure, and the vibration detection unit 8 may be provided at other locations on the flange portion 111, for example, on the side of the flange portion 111, or may be provided at a location other than the flange portion 111, for example, on the main body portion 110.

[0081] The base 11 has a recess 114 that opens to the first arm 20 side, and the vibration detection unit 8 is installed in the recess 114. This makes it possible to detect vibration of the base 11 while protecting the inertial sensor 81.

[0082] The first motor 31 is provided on the base 11 and serves as a first drive source for rotationally driving the first arm 20, and the first motor 31 and the vibration detection unit 8 are arranged offset from each other when viewed from the direction of the first rotation axis J1. This allows easy maintenance of the first motor 31 and also allows easy maintenance of the inertial sensor 81.

[0083] The first joint 29 is provided as a connection part that connects the base 11 and the first arm 20, and the first joint 29 and the vibration detection unit 8 are arranged to be shifted from each other when viewed from the direction of the first rotation axis J1. This allows easy maintenance of the first joint 29 and also easy maintenance of the inertial sensor 81.

[0084] As described above, the robot system 100 includes the base 11 placed on the lower surface 912, which is the installation surface of the top board 91, the first arm 20 connected to the base 11 so as to be rotatable about a first rotation axis J1 relative to the base 11, the second arm 40 connected to the first arm 20 so as to be rotatable about a second rotation axis J2 parallel to the first rotation axis J1 relative to the first arm 20, and the second arm 40 connected to the first arm 20 so as to be rotatable about a third rotation axis J3 parallel to the first rotation axis J1 relative to the second arm 40 and to be movable along the axial direction of the third rotation axis J3. The robot system 100 includes an operating shaft 61 as a shaft connected to the base 11 and having an upper end 610 on the first arm 20 side, a vibration detection unit 8 provided on the base 11, and a control unit 71 that controls the driving of at least one of the first arm 20, the second arm 40, and the operating shaft 61 based on the detection value of the vibration detection unit 8, and the length l1 of the operating shaft 61 from the second arm 40 to the upper end 610 of the operating shaft 61 is shorter than the distance D along the axial direction of the third rotation axis J3 between the second arm 40 and the first arm 20. By performing such control, it is possible to perform a highly accurate operation. In particular, the robot system 100 can detect the vibration of the base 11 more accurately, and therefore can perform a more accurate operation.

[0085] The control unit 71 performs vibration suppression control on at least one of the first arm 20, the second arm 40, and the working shaft 61 serving as a shaft, based on the detection value of the vibration detection unit 8. This makes it possible to perform work with higher accuracy.

[0086] The control performed by the control unit 71 is not limited to vibration suppression control, and may be one of the control patterns 1 to 3 exemplified below. The control patterns 1 to 3 may be arbitrarily combined to perform control.

[0087] (Control pattern 1) When the amplitude of vibration calculated based on the detection value of the vibration detection unit 8 exceeds a first threshold value, the driving of the robot arm 10 is stopped. This makes it possible to improve the accuracy of the work and also to increase safety.

[0088] (Control pattern 2) When the amplitude of vibration calculated based on the detection value of the vibration detection unit 8 exceeds the second threshold, the robot arm 10 is decelerated. This can improve the accuracy of the work and also the safety. The degree of deceleration may be determined in advance or according to the magnitude of the amplitude.

[0089] (Control pattern 3) When the amplitude of vibration calculated based on the detection value of the vibration detection unit 8 exceeds a second threshold, the operation parameters set in the robot arm 10 are changed. This makes it possible to improve the accuracy of the work and also to increase safety. Examples of the operation parameters include a mass coefficient, a viscosity coefficient, an elasticity coefficient, and a target position.

[0090] <Second embodiment> FIG. 5 is a partial cross-sectional view of a base and a vibration detection unit provided in a robot and a robot system according to a second embodiment of the present invention.

[0091] Hereinafter, a second embodiment of the robot system of the present invention will be described with reference to FIG. 5. The following description will focus on the differences from the first embodiment, and descriptions of similar points will be omitted.

[0092] As shown in FIG. 5, the robot 1 includes a vibration amplifying member 82 that supports the inertial sensor 81 of the vibration detection unit 8. The vibration amplifying member 82 has a function of amplifying the vibration of the base 11 and transmitting it to the inertial sensor 81. The vibration amplifying member 82 is an elongated member that stands upright from the bottom in the main body 110 of the base 11. More specifically, the robot 1 has a narrow, plate-like vibration amplifying member 82 that stands upright on the upper surface of the flange 111 in the main body 110, and the vibration detection unit 8 (inertial sensor 81) is installed on the upper end of the vibration amplifying member 82. The vibration amplifying member 82 is made of, for example, a metal material such as stainless steel or aluminum, or a hard resin material. This allows the vibration to be amplified appropriately and sufficiently.

[0093] The configuration of the vibration amplifying member 82 is not limited to the above, and the shape may be other than bar-like, frame-like, etc. The vibration amplifying member 82 may be composed of a plurality of long objects. The vibration amplifying member 82 may be installed in a portion other than the bottom of the base 11, for example, in a side portion or ceiling portion of the main body 110.

[0094] In this manner, the robot 1 includes a vibration amplifying member 82 that is disposed within the base 11 and supports the vibration detection unit 8. This makes it possible to amplify the vibration of the base 11, and therefore to detect the vibration with higher accuracy.

[0095] Furthermore, the vibration amplifying member 82 is longer than the vertical length of the first motor 31. That is, the vibration amplifying member 82 supports the vibration detection unit 8 at a position (above) higher than the first motor 31. This makes it possible to more effectively amplify the vibration of the base 11, and to detect the vibration with higher accuracy.

[0096] Thus, the robot 1 is provided with the first motor 31 as a first drive source that is provided on the base 11 and drives the first arm 20 to rotate, and the vibration amplifying member 82 supports the vibration detecting unit 8 at a position higher than the first motor 31. This makes it possible to more effectively amplify the vibration of the base 11, and to detect the vibration with higher accuracy.

[0097] In each of the above embodiments, the installation surface of the robot 1 is the top plate 91 located at the top of the stand 9, but this is not limited to the above. The installation surface of the robot 1 may be, for example, the ceiling of the workroom, a beam, pillar, brace, or other structure installed on or near the ceiling, or a hoist rail, the stand 9, or a wall surface of the workroom.

[0098] Although the robot and robot system of the present invention have been described in the illustrated embodiments, the present invention is not limited thereto. Each part of the robot system can be replaced with any structure that can perform a similar function. Any structure may be added to the robot system. The present invention may also be a combination of at least a part of the features of the first embodiment and at least a part of the features of the second embodiment. [Explanation of symbols]

[0099] 1...robot, 7...control device, 8...vibration detection unit, 9...base, 10...robot arm, 11...base, 20...first arm, 29...first joint portion, 291...plate, 30...first motor unit, 31...first motor, 32...belt, 33...reduction gear, 331...pulley, 332...reduction gear body, 34...shaft, 40...second arm, 41...first member, 42...second member, 49...second joint portion, 491...plate, 50...second motor unit, 51...second motor, 52...belt, 53...reduction gear, 531...pulley, 532...reduction gear body, 54...shaft, 55...cover member, 60...working head, 61...operating shaft, 62...cover member, 65...driving unit, 66...shaft lifting mechanism, 67 ...Axis rotation mechanism, 71...Control unit, 72...Memory unit, 73...Communication unit, 81...Inertial sensor, 82...Vibration amplification member, 90...Hand, 91...Top plate, 92...Leg, 100...Robot system, 110...Main body, 111...Flange, 112...Fixed member, 113...Lower surface, 114...Recess, 115...Bottom surface, 116...Inner surface, 610...Upper end, 611...Lower end, 661...Axis lift motor, 662...Lead screw mechanism, 663...Belt, 671...Axis rotation motor, 672...Spline mechanism, 673...Belt, 911...Upper surface, 912...Lower surface, 913...Through hole, 914...Through hole, 6621...Female thread block, 6721...Boss block, J1...First rotating shaft, J2...Second rotating shaft, J3...Third rotating shaft

Claims

1. A base to be installed on an installation surface; a first arm connected to the base so as to be rotatable about a first rotation axis with respect to the base; a second arm connected to the first arm so as to be rotatable about a second rotation axis parallel to the first rotation axis with respect to the first arm; a shaft connected to the second arm so as to be rotatable about a third rotation axis parallel to the first rotation axis and movable along an axial direction of the third rotation axis, the shaft having an end on the first arm side; A vibration detection unit provided on the base, a length of the shaft from the second arm to the end of the shaft is shorter than a distance along an axial direction of the third rotation axis between the second arm and the first arm.

2. The base has a flange portion fixed to the installation surface, The robot according to claim 1 , wherein the vibration detection unit is provided on the flange portion.

3. the base has a recess that opens toward the first arm, The robot according to claim 1 , wherein the vibration detection unit is disposed within the recess.

4. The robot according to claim 1 , further comprising a vibration amplifying member disposed within the base and supporting the vibration detecting unit.

5. a first drive source provided on the base and configured to drive the first arm to rotate; The robot according to claim 4 , wherein the vibration amplifying member supports the vibration detecting unit at a position higher than the first driving source.

6. a first drive source provided on the base and configured to drive the first arm to rotate; The robot according to claim 1 , wherein the first driving source and the vibration detection unit are arranged to be shifted from each other when viewed from the first rotation axis direction.

7. a connection portion that connects the base and the first arm, The robot according to claim 1 , wherein the connection portion and the vibration detection portion are arranged to be shifted from each other when viewed from the first rotation axis direction.

8. A base to be installed on an installation surface; a first arm connected to the base so as to be rotatable about a first rotation axis with respect to the base; a second arm connected to the first arm so as to be rotatable about a second rotation axis parallel to the first rotation axis with respect to the first arm; a shaft connected to the second arm so as to be rotatable about a third rotation axis parallel to the first rotation axis and movable along an axial direction of the third rotation axis, the shaft having an end on the first arm side; A vibration detection unit provided on the base; a control unit that controls driving of at least one of the first arm, the second arm, and the shaft based on a detection value of the vibration detection unit, A robot system, characterized in that the length of the shaft from the second arm to the end of the shaft is shorter than the distance along the axial direction of the third rotation axis between the second arm and the first arm.

9. The robot system according to claim 8 , wherein the control unit performs vibration suppression control on at least one of the first arm, the second arm, and the shaft based on a detection value of the vibration detection unit.

Images