Ceiling-mounted robots and ceiling-mounted robotic systems

Abstract

To provide a ceiling-mounted robot that can improve the accuracy of vibration detection. [Solution] The ceiling-mounted robot 1 comprises a base 110, a first arm 120 overlapping the base 110, a joint 25 that holds the first arm 120 so as to be rotatable around a first axis J1 relative to the base 110, a second arm 130 overlapping the first arm 120, a joint 35 that holds the second arm 130 so as to be rotatable around a second axis J2, and an operating shaft 41 provided on the other end of the second arm 130 in the longitudinal direction and rotating around a third axis J3. The first arm 120 comprises a housing 121, a motor 31 that rotates the second arm 130 via a belt 32 and pulley 33 as a transmission mechanism, and an inertial sensor 8 supported on a top plate 1211 and provided in a position that overlaps with the motor 31 in a plan view, and which detects at least one of angular velocity and acceleration.

Description

Technical Field

[0001] The present invention relates to an overhead robot and an overhead robot system.

Background Art

[0002] As an industrial overhead robot, for example, the overhead robot described in Patent Document 1 is known. The overhead robot described in Patent Document 1 includes a base, a first arm that is connected to the base via a first joint portion so as to be rotatable in a horizontal plane about a first joint axis, a second arm that is connected to the first arm via a second joint portion so as to be rotatable in a horizontal plane about a second joint axis, and a working axis attached to the second arm. Further, a second joint axis motor for driving the second arm is provided on the first arm.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is an increasing demand for vibration control to suppress the sway of the arm during operation using an inertial sensor in such an overhead robot. However, depending on the way the inertial sensor is arranged, there is a risk that the detection accuracy of the inertial sensor and the basic performance of the overhead robot may be impaired.

Means for Solving the Problems

[0005] The ceiling-mounted robot of the present invention comprises a base, a first arm whose longitudinal end overlaps the base in a plan view, a first joint provided on the end of the first arm and which holds the first arm so as to be rotatable around a first axis relative to the base, a second arm whose longitudinal end overlaps the other longitudinal end of the first arm in a plan view, a second joint provided on the end of the second arm and which holds the second arm so as to be rotatable around a second axis parallel to the first axis relative to the first arm, and the second arm The first arm comprises a housing having a first plate portion and a second plate portion facing the first plate portion, a motor that rotates the second arm via a transmission mechanism, and an inertial sensor supported by the second plate portion and located at a position that overlaps with the motor in a plan view, or on the other end of the first arm beyond the motor, which detects at least one of angular velocity and acceleration.

[0006] The ceiling-mounted robot system of the present invention comprises the ceiling-mounted robot and a controller for controlling the ceiling-mounted robot. [Brief explanation of the drawing]

[0007] [Figure 1] An overall perspective view of a ceiling-mounted robot system equipped with the ceiling-mounted robot of this embodiment. [Figure 2] A partially enlarged perspective view of Figure 1. [Figure 3] Side view of the ceiling-mounted robot shown in Figure 1. [Figure 4A] A partial cross-sectional view of the ceiling-mounted robot shown in Figure 3. [Figure 4B] Figure 3 is a plan view of the ceiling-mounted robot as seen from the negative Z-axis side. [Figure 5] Block diagram of the ceiling-mounted robot system shown in Figure 1. [Figure 6] Side view of the ceiling-mounted robot according to Embodiment 2. [Figure 7] A partial cross-sectional view of the ceiling-mounted robot shown in Figure 6. [Figure 8] Figure 6 is a plan view of the ceiling-mounted robot as seen from the negative Z-axis side. [Modes for carrying out the invention]

[0008] In embodiments of the present invention, the components shown in each drawing may be shown at different dimensional scales for clarity. Drawings sometimes depict three axes: the X, Y, and Z axes, which are mutually orthogonal. The X and Y axes are positioned so that the plane containing them is horizontal, while the Z axis is positioned so that the tip of the arrow points vertically upward.

[0009] In the following explanation, the tip of the arrows on the three axes may be referred to as the "positive side," and the base of the arrow as the "negative side." The direction parallel to the X-axis may be referred to as the "X-axis direction," the direction parallel to the Y-axis as the "Y-axis direction," and the direction parallel to the Z-axis as the "Z-axis direction."

[0010] In the following, "planar view" refers to viewing an object from either the positive Z-axis side or the negative Z-axis side of the object. The positive Z-axis side may be described as "upwards," and the negative Z-axis side may be described as "downwards."

[0011] Furthermore, the description of "the top surface of a certain configuration" refers to the surface on the positive Z-axis side of that configuration; for example, "the top surface of the top plate" refers to the surface on the positive Z-axis side of the top plate. Furthermore, the description of "the underside of a certain configuration" refers to the surface on the negative side of the Z-axis direction of that configuration; for example, "the underside of the top plate" refers to the surface on the negative side of the Z-axis direction of the top plate.

[0012] Preferred embodiments of the ceiling-mounted robot 1 and ceiling-mounted robot system 100 of the present invention will be described below.

[0013] 1. Embodiment 1 1.1. Overall configuration of ceiling-mounted robots and ceiling-mounted robot systems FIG. 1 is an overall perspective view of an overhead robot system 100 including an overhead robot 1 according to Embodiment 1. FIG. 2 is a partially enlarged perspective view of FIG. 1.

[0014] The overhead robot system 100 is an industrial robot that automates various operations such as assembly in a factory or the like, replacing a human. The overhead robot system 100 includes an overhead robot 1, an inertial sensor 8 that detects vibrations of the overhead robot 1, and a control device 7 that controls the overhead robot 1.

[0015] The overhead robot 1 is a horizontal articulated robot (SCARA Robot) whose arm operates in the horizontal direction. The overhead robot 1 is installed in a state of being suspended from the top plate 91 of the gantry 9. The gantry 9 is installed, for example, on a manufacturing line of a factory that manufactures precision devices such as mobile phones, smartphones, and tablet terminals. The overhead robot 1 is controlled by the control device 7 and performs operations such as gripping, transporting, processing, and assembling on a workpiece 95 such as a precision device or a part placed on the workbench 92. In the present embodiment, the control device 7 is an example of a controller.

[0016] Note that the installation surface of the overhead robot 1 is not limited to the top plate 91 of the gantry 9. The installation surface of the overhead robot 1 may be, for example, the ceiling or wall surface of a workroom, a beam, a column, a crossbar, other structures, a hoist rail, or the like. The overhead robot 1 includes wall-mounted or wall-attached robots having a side wall as the installation surface.

[0017] The gantry 9 has a top plate 91, a workbench 92, frame-shaped legs 93, and an inertial sensor 8. The overhead robot 1 is installed on the top plate 91. The top plate 91 has an upper surface 911 and a lower surface 912, and is provided such that the surface on which the overhead robot 1 is installed is horizontal. The top plate 91 has through holes 913 and 914 that penetrate in the thickness direction thereof.

[0018] The through-hole 913 is a window that allows an operator to access the top plate 91 from above when performing maintenance on the drive unit 30, which will be described later. The through-hole 914 is the hole through which the ceiling-mounted robot 1 is installed, and the base 110 is inserted through the through-hole 914.

[0019] The inertial sensor 8 includes an inertial sensor 8a provided on the upper surface 911 of the top plate 91 of the frame 9, and an inertial sensor 8b provided on the upper surface of the workbench 92.

[0020] Since the inertial sensor 8a is positioned on the top plate 91 on which the ceiling-mounted robot 1 is installed, it can accurately detect vibrations occurring in the frame 9. The information detected by the inertial sensor 8a is sent to the control device 7 and used to suppress vibrations of the ceiling-mounted robot 1, in particular vibrations of the hand 42 attached to the tip of the work head 40.

[0021] Since the inertial sensor 8b is positioned on the workbench 92, it can accurately detect vibrations occurring on the workbench 92, in other words, how the workpiece 95 is actually vibrating. The information detected by the inertial sensor 8b is sent to the control device 7 and used to suppress vibrations of the overhead robot 1 and to perform precise work. For example, based on the information detected by the inertial sensor 8b, the control device 7 corrects the relative position between the overhead robot 1 and the workpiece 95. Therefore, the control device 7 can perform precise positioning.

[0022] In this embodiment, the inertial sensor 8 is also provided on the ceiling-mounted robot 1. The control device 7 performs vibration damping control using the detection signals from each inertial sensor 8 provided on at least one of the ceiling-mounted robot 1 and the frame 9. The inertial sensor 8 will be described in detail in section 1.2.3 below. The vibration damping control performed by the control device 7 will be described in detail in section 1.2.4 below.

[0023] As shown in Figure 2, the ceiling-mounted robot 1 has a base 110 and a robot arm 10 connected to the base 110. The robot arm 10 has a first arm 120, a second arm 130, and a work head 40.

[0024] In a plan view, the first arm 120 is provided so that one end in the longitudinal direction overlaps the base 110 via a joint 25. The joint 25 is provided on one end of the first arm 120 in the longitudinal direction and holds the first arm 120 so that it can rotate around the first axis J1 relative to the base 110. In this embodiment, the first axis J1 is a virtual axis extending along the vertical direction and represents the axis of rotation of the first arm 120. In this embodiment, the joint 25 is an example of a first joint.

[0025] In a plan view, the second arm 130 is provided such that one end in the longitudinal direction overlaps the other end in the longitudinal direction of the first arm 120 via a joint 35. The joint 35 is provided on one end in the longitudinal direction of the second arm 130 and holds the second arm 130 so that it can rotate around a second axis J2 parallel to the first axis J1 relative to the first arm 120. In this embodiment, the second axis J2 is a virtual axis extending along the vertical direction and represents the axis of rotation of the second arm 130. The second axis J2 and the first axis J1 are parallel. In this embodiment, the joint 35 is an example of a second joint.

[0026] The working head 40 is provided on the other end of the second arm 130 in the longitudinal direction. The working head 40 comprises an operating shaft 41 and a hand 42. In this embodiment, the operating shaft 41 is an example of a shaft.

[0027] An inertial sensor 8 is installed on the first arm 120. The inertial sensor 8 detects vibrations of the first arm 120 and sends a detection signal consisting of vibration data to the control device 7. Based on the detection signal detected by the inertial sensor 8, the control device 7 controls each part of the ceiling-mounted robot 1 so that vibrations of the first arm 120, the ceiling-mounted robot 1, the frame 9, and / or the workpiece 95 are suppressed.

[0028] Thus, the ceiling-mounted robot system 100 of this embodiment can improve vibration damping performance by equipping the ceiling-mounted robot 1 with an inertial sensor 8. Therefore, it is possible to realize a ceiling-mounted robot 1 and a ceiling-mounted robot system 100 that are capable of servo control with excellent speed, accuracy, and / or energy efficiency. Furthermore, in this embodiment, by devising the arrangement of the inertial sensors 8, both the detection accuracy of the inertial sensors 8, for example, the accuracy of the sway data, and the basic performance of the ceiling-mounted robot 1, for example, its workability, are achieved. The arrangement of the inertial sensors 8 will be explained in section 1.2.3.1 below.

[0029] 1.2. Detailed Configuration of the Ceiling-Mounted Robot The detailed configuration of each part of the ceiling-mounted robot 1 will be described below with reference to Figures 3 to 4B. Figure 3 is a side view of the ceiling-mounted robot 1 shown in Figure 1. Figure 4A is a partial cross-sectional view of the ceiling-mounted robot 1 shown in Figure 3. Figure 4B is a plan view of the ceiling-mounted robot 1 shown in Figure 3, viewed from the negative Z-axis side.

[0030] As shown in Figure 3, the ceiling-mounted robot 1 has a base 110 and a robot arm 10 connected to the base 110.

[0031] 1.2.1. Base The base 110 is located at the very top of the ceiling-mounted robot 1 and is attached to the top plate 91 of the frame 9. The base 110 comprises a main body 11, a plate-shaped base plate 13 provided at the lower part of the main body 11, and a drive unit 20 provided inside the main body 11 for rotating the first arm 120 around the first axis.

[0032] The main body 11 and the base plate 13 constitute the housing, and a portion of the drive unit 20 is housed within the housing. The base 110 is installed on the top plate 91 by fixing the base plate 13 together with the fittings 12 to the top surface 911 and / or bottom surface 912 of the top plate 91 using fastening members such as bolts, screws, and pins. The ceiling-mounted robot 1 functions as a ceiling-mounted SCARA robot when its base 110 is installed on the top plate 91.

[0033] The drive unit 20 includes a motor 21, a belt 22, a pulley 23, and a joint 25. The rotation of the motor 21 is transmitted to the joint 25 via the belt 22 and pulley 23. Since the motor 21, belt 22, and pulley 23 are housed within the main body 11, foreign matter such as dust and dirt is prevented from entering the motor 21 and other components, and foreign matter is prevented from being discharged from the motor 21 and other components to the outside of the robot arm 10.

[0034] The joint portion 25 includes a reduction gear 26 and a flange 27. In this embodiment, the speed reducer 26 is a harmonic drive gear speed reducer. However, the speed reducer 26 may be other types of speed reducers, such as a planetary gear speed reducer. One side of the flange 27 is fixed to the output shaft of the reduction gear 26, and the other side is fixed to the first arm 120.

[0035] The gearbox 26 includes a wave generator 261, a flex spline 262, and a circular spline 263. The wave generator 261 is the input shaft of the gearbox 26 and is fixed to the pulley 23. The flex spline 262 is the output shaft of the gearbox 26 and is fixed to the flange 27. The circular spline 263 is the fixed shaft and is fixed to the base plate 13. Alternatively, the flex spline 262 may be fixed to the base plate 13 as the fixed shaft, and the circular spline 263 may be fixed to the flange 27 as the output shaft.

[0036] Cables such as power lines and various signal lines, and / or other piping, which are connected to the drive unit 30, drive unit 50, work head 40, and inertial sensor 8 (described later), are inserted through the hollow tube 28.

[0037] 1.2.2. Robot Arm The robot arm 10 has a first arm 120, a second arm 130, and a work head 40.

[0038] 1.2.2.1. First Arm The first arm 120 is cantilevered to the base 110 at one end of an arm that extends horizontally, via a joint 25. The first arm 120 moves horizontally by rotating around the first axis J1, which is the axis of rotation.

[0039] The first arm 120 includes a housing 121, a drive unit 30, and an inertial sensor 8. The housing 121 has a roughly rectangular parallelepiped shape and includes a plate-shaped top plate 1211 and a bottom plate 1212 facing the top plate 1211. In this embodiment, the top plate 1211 is an example of a second plate portion, and the bottom plate 1212 is an example of a first plate portion.

[0040] The drive unit 30 rotates the second arm 130 around the second axis J2. The drive unit 30 includes a motor 31, a belt 32, a pulley 33, and a joint 35.

[0041] The motor 31 is mounted on the lower surface 1212b of the bottom plate 1212 of the first arm 120, while covered by the cover 122. However, the motor 31 does not necessarily need to be covered by the cover 122.

[0042] The work head 40 is positioned on the lower surface 1212b side of the bottom plate 1212 of the first arm 120, but the motor 31 is positioned so as not to interfere with the work head 40, approximately in the center of the longitudinal direction of the first arm 120, in other words, between the first axis J1 and the second axis J2, more specifically between the cylindrical portion 132 of the second arm 130 and the work head 40.

[0043] The cover 122 is provided so as to cover the motor 31. The rotation of the motor 31 is transmitted to the joint 35 via the belt 32 and pulley 33. The belt 32 and pulley 33 are located inside the housing 121 and are mounted on the upper surface 1212a of the bottom plate 1212. In this embodiment, the belt 32 and pulley 33 are an example of a transmission mechanism.

[0044] The joint portion 35 is positioned on the other end side in the longitudinal direction of the first arm 120. The joint portion 35 includes a reduction gear 36 and a flange 37. In this embodiment, the speed reducer 36 is a harmonic drive gear speed reducer. However, the speed reducer 36 may be other types of speed reducers, such as a planetary gear speed reducer.

[0045] The gearbox 36 includes a wave generator 361, a flex spline 362, and a circular spline 363. The wave generator 361 is the input shaft of the gearbox 36 and is fixed to the pulley 33. The flex spline 362 is the output shaft of the gearbox 36 and is fixed to the flange 37. The circular spline 363 is the fixed shaft and is fixed to the first arm 120. Alternatively, the flex spline 362 may be fixed to the first arm 120 as the fixed shaft, and the circular spline 363 may be fixed to the flange 37 as the output shaft.

[0046] One side of the flange 37 is fixed to the output shaft of the reduction gear 36, and the other side is fixed to the second arm 130.

[0047] Cables such as power lines and various signal lines, and / or other piping, which are connected to the drive unit 50, work head 40, and inertial sensor 8 (described later), are inserted through the hollow tube 38.

[0048] The inertial sensor 8 includes an inertial sensor 8c located on the lower surface 1211b of the top plate 1211, in a position that overlaps with the motor 31 in a plan view, and an inertial sensor 8d located on the other end of the first arm 120 in the longitudinal direction, further than the motor 31. It is not necessary for both inertial sensors 8c and 8d to be provided; at least one of them is sufficient.

[0049] 1.2.2.2. Second Arm The second arm 130 is cantilevered to the other end of the first arm 120 via a joint 35 at one end of the horizontally extending arm.

[0050] The second arm 130 moves horizontally by rotating around the second axis J2, which is the axis of rotation. The first axis J1 of the first arm 120 and the second axis J2 of the second arm 130 are parallel, but they are offset horizontally. In other words, the first axis J1 and the second axis J2 are separated by a predetermined distance horizontally. This allows for a wide range of motion for the robot arm 10.

[0051] The second arm 130 has a housing portion 131 and a cylindrical portion 132. The cylindrical portion 132 is provided in the second arm 130 between the housing portion 131 and the flange 37. One side of the cylindrical portion 132 is fixed to the flange 37, and the other side is connected to the housing portion 131. In other words, the cylindrical portion 132 functions as a joint connecting the flange 37 and the housing portion 131. The cylindrical portion 132 is provided so that its cylindrical part surrounds the second axis J2, and its length along the second axis J2 is such that, for example, the second arm 130 can rotate 360° relative to the first arm 120. For example, the length of the work head 40 from the top surface of the top plate of the housing portion 131 to the upper end of the work head 40 is shorter than the distance along the axial direction of the third axis J3 between the top surface of the top plate of the housing portion 131 and the lower surface 1212b of the bottom plate 1212 of the first arm 120. As a result, even when the operating shaft 41 is at its highest position, the working head 40 does not interfere with the first arm 120, and the second arm 130 can pass below the first arm 120. In other words, the second arm 130 can rotate 360° relative to the first arm 120, regardless of the vertical position of the working head 40.

[0052] The housing 131 is equipped with a drive unit 50 and a work head 40. The drive unit 50 has a motor 51, which is controlled by the control device 7 to drive the work head 40.

[0053] The work head 40 includes an operating shaft 41 and a hand 42. The work head 40 and part of the drive unit 50 are housed in the cover 135. A portion of the operating shaft 41 is housed in a bellows-shaped cover 43.

[0054] The actuation shaft 41 extends longitudinally along the third axis J3, is driven by the drive unit 50, slides vertically along the third axis J3, and / or rotates around the third axis J3. In this embodiment, the third axis J3 is a virtual axis extending vertically and represents the axis of rotation of the actuation shaft 41. The third axis J3 is parallel to the first axis J1 and the second axis J2.

[0055] The operating shaft 41 is a hollow shaft type with a hollow center. Cables such as power lines and various signal lines, and / or other piping are inserted into the hollow of the operating shaft 41 and connected to the hand 42. Note that the operating shaft 41 is not limited to a hollow shaft type. Cables connected to the hand 42 may also be connected via the outside of the operating shaft 41.

[0056] The hand 42 is an end effector that is controlled by the control device 7 to perform tasks such as gripping, transporting, processing, and assembling workpieces 95, such as precision instruments and parts, placed on the workbench 92.

[0057] The hand 42 is detachably attached to the lower end of the operating shaft 41. The hand 42 is fitted with an end effector suitable for the task, selected from a variety of end effectors. Examples of end effectors include grippers, suction end effectors, application-specific end effectors, and robotic hands.

[0058] The drive unit 50 includes an axis lifting mechanism that slides the operating shaft 41 in the vertical direction, and an axis rotation mechanism that rotates the operating shaft 41 around the third axis J3.

[0059] The motor 51 includes an axle lifting motor 511 and an axle rotation motor 512. The axle lifting motor 511 and the axle rotation motor 512 are installed adjacent to each other along the longitudinal direction of the second arm 130.

[0060] The shaft lifting mechanism consists of a shaft lifting motor 511, a belt 52, a pulley 53, and a lead screw mechanism 54. The lead screw mechanism 54 consists of a screw groove (not shown) formed on the outer circumferential surface of the operating shaft 41 and a ball screw having a female screw block 541 that is rotatably supported in the housing portion 131.

[0061] The shaft lifting mechanism transmits the rotation of the shaft lifting motor 511 to the female screw block 541 via the belt 52 and pulley 53, and rotates the female screw block 541 to move the operating shaft 41 along the third shaft J3, that is, upward or downward.

[0062] The axial rotation mechanism consists of an axial rotation motor 512, a belt 56, a pulley 57, and a spline mechanism 58. The spline mechanism 58 consists of a spline groove (not shown) formed on the outer circumferential surface of the operating shaft 41 and a ball spline having a boss block 581 that is rotatably supported on the housing portion 131. The spline mechanism 58 supports the operating shaft 41 so that it can slide in the vertical direction.

[0063] The axial rotation mechanism transmits the rotation of the axial rotation motor 512 to the boss block 581 via the belt 56 and pulley 57, causing the boss block 581 to rotate, thereby rotating the operating shaft 41 around the third shaft J3.

[0064] The shaft lifting motor 511 and the shaft rotation motor 512 are positioned in the housing portion 131 between the operating shaft 41 and the cylindrical portion 132. In other words, the shaft lifting motor 511 and the shaft rotation motor 512 are positioned between the operating shaft 41 and the second shaft J2, or between the third shaft J3 and the second shaft J2.

[0065] 1.2.3. Inertial Sensor The inertial sensor 8 is a sensor device that houses an inertial sensor element 81 for detecting inertial force and a circuit board 82 on which the inertial sensor element 81 and a processor, interface chip, etc. (not shown) are mounted, in a package. Note that the inertial sensor 8 does not necessarily need to be housed in a package; it may be mounted on the housing 131 in its circuit board 82 form.

[0066] In this embodiment, the inertial sensor element 81 includes a total of six sensor elements: acceleration in the X-axis direction, acceleration in the Y-axis direction, acceleration in the Z-axis direction, angular velocity around the X-axis, angular velocity around the Y-axis, and angular velocity around the Z-axis. In other words, the inertial sensor 8 is an IMU (Inertial Measurement Unit) that detects acceleration in three mutually orthogonal axes and angular velocity around the three axes.

[0067] The inertial sensor element 81 is not limited to an IMU. The inertial sensor element 81 may be an acceleration sensor element that detects acceleration in one to three of the X, Y, and Z axes, an angular velocity sensor element that detects angular velocity around one to three of the X, Y, and Z axes, or a sensor element with a configuration combining these.

[0068] Furthermore, as the inertial sensor element 81, for example, a quartz acceleration sensor element using a quartz oscillator can be used. The type of inertial sensor element 81 can be selected according to the application, and for example, a Si-MEMS (Micro Electro Mechanical Systems) sensor element using silicon (Si) as the material can be used. Furthermore, the inertial sensor 8 may be equipped with a display, memory, etc. Also, the inertial sensor 8 may be configured to wirelessly transmit detected values ​​to an external device.

[0069] In this embodiment, the inertial sensor 8 is provided on the frame 9 and the first arm 120 of the ceiling-mounted robot 1. The inertial sensor 8, installed on the first arm 120, detects at least one of the angular velocity and acceleration at the installed position and outputs a detection signal.

[0070] Vibrations from the first arm 120 can adversely affect the working accuracy of the ceiling-mounted robot 1. For example, the first arm 120 is subjected to horizontal forces and vibrates due to rotation around the first axis J1 of the first arm 120, rotation around the second axis J2 of the second arm 130, rotation around the third axis J3 of the operating shaft 41, and / or the swaying of the frame 9. As a result, the position of the hand 42 may shift from the target position.

[0071] Furthermore, the first arm 120 is subjected to vertical forces and vibrates due to the movement of the operating shaft 41 along the third axis J3, the gripping or release of the workpiece 95 by the hand 42, and / or the shaking of the frame 9. As a result, the position of the hand 42 may shift from the target position.

[0072] Therefore, when performing work with the hand 42, it is preferable to control the drive of each motor 21, 31, and 51 according to the nature, characteristics, and degree of vibration, so that the hand 42 does not deviate from the target position.

[0073] In this embodiment, due to the circumstances described above, the first arm 120 is equipped with an inertial sensor 8. The detection signal from the inertial sensor 8 is used to drive and control each motor 21, 31, 511, and 512 so as to suppress vibration. This type of control is called vibration damping control. The ceiling-mounted robot 1 of this embodiment is configured to improve the work accuracy of the ceiling-mounted robot 1 by performing vibration damping control.

[0074] However, depending on how the inertial sensors 8 are arranged, there is a risk that the detection accuracy of the inertial sensors 8 placed on the first arm 120 and the basic performance of the ceiling-mounted robot 1 may be impaired. Therefore, in this embodiment, several measures have been taken to ensure that the detection accuracy of the inertial sensors 8 and the basic performance of the ceiling-mounted robot 1 are not impaired by the arrangement of the inertial sensors 8, and furthermore, to improve the detection accuracy of the inertial sensors 8 and the basic performance of the ceiling-mounted robot 1. The following describes the design features implemented for the placement of the inertial sensor 8 on the first arm 120.

[0075] 1.2.3.1. Placement of inertial sensor 8c As shown in Figures 4A and 4B, the inertial sensor 8c is positioned on the lower surface 1211b of the top plate 1211 of the first arm 120, in a position that overlaps with the motor 31 in a plan view. The motor 31 is located on the lower surface 1212b of the bottom plate 1212 of the first arm 120. In other words, the inertial sensor 8c is positioned on a different surface of the first arm 120 from the motor 31. Therefore, the inertial sensor 8c is less susceptible to the vibrations of the motor 31 and can accurately detect vibrations of the first arm 120.

[0076] Furthermore, the inertial sensor 8c is located on the base 110 side of the first arm 120. In other words, the inertial sensor 8 is located away from the joint 35. Therefore, the inertial sensor 8c is less affected by vibrations of the joint 35 and can accurately detect vibrations of the first arm 120.

[0077] 1.2.3.2. Placement of inertial sensor 8d The inertial sensor 8d is located on the lower surface 1211b of the top plate 1211 of the first arm 120, on the other end of the first arm 120 in the longitudinal direction, relative to the motor 31. In other words, the inertial sensor 8d is positioned on a different surface of the first arm 120 from the motor 31. Therefore, the inertial sensor 8d is less susceptible to vibrations from the motor 31 and can accurately detect vibrations from the first arm 120.

[0078] Furthermore, the inertial sensor 8d is located in a plan view on the other end of the first arm 120, relative to the motor 31, and overlaps with the joint 35. Therefore, the inertial sensor 8d is less susceptible to vibrations from the motor 31 and can accurately detect vibrations at the tip of the first arm 120.

[0079] Furthermore, the inertial sensor 8d is located closer to the base 110 than the motor 31. In other words, it is located away from the joint 35. Therefore, the inertial sensor 8d is less affected by vibrations of the joint 35 and can accurately detect vibrations of the first arm 120.

[0080] 1.2.4. Ceiling-mounted robotic system Next, the configuration of the ceiling-mounted robot system 100 will be described based on Figures 1 and 5. Figure 5 is a block diagram of the ceiling-mounted robot system 100 shown in Figure 1.

[0081] As described above, the ceiling-mounted robot system 100 includes a ceiling-mounted robot 1, an inertial sensor 8 for detecting vibrations of the ceiling-mounted robot 1, and a control device 7 for controlling the ceiling-mounted robot 1.

[0082] In this embodiment, the control device 7 is separate from the ceiling-mounted robot 1 and installed next to the ceiling-mounted robot 1. The control device 7 may be built into the ceiling-mounted robot 1, for example, in the base 110, or it may be installed in a location away from the ceiling-mounted robot 1, for example, in a control room provided in a separate building.

[0083] As shown in Figure 5, 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 that they can communicate with one another, for example, via a bus. 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 memory unit 72.

[0084] Signals generated by the control unit 71 are transmitted to each part of the ceiling-mounted robot 1 via the communication unit 73, and signals from each part of the ceiling-mounted robot 1 are received by the control unit 71 via the communication unit 73. This allows the robot arm 10 to perform predetermined tasks under predetermined conditions.

[0085] Furthermore, the control unit 71 includes a position command generation unit, a motor control unit, and a plurality of motor drivers. The motor control unit performs noise processing, coordinate transformation processing, etc., on the output value of the inertial sensor 8 and calculates the magnitude and direction of the vibration detected by the inertial sensor 8. It then generates a feedback value that cancels out such vibration components and uses this feedback value to control each of the motors 21, 31, 511, and 512 of the robot arm 10.

[0086] Specifically, the position command generation unit calculates the target positions of the operating axis 41 and hand 42 based on the processing performed by the ceiling-mounted robot 1, and generates a trajectory for moving the operating axis 41 and hand 42 to the calculated target positions. The position command generation unit also calculates the rotation angles of each motor 21, 31, 511, and 512 at predetermined control cycles so that the operating axis 41 and hand 42 move along the generated trajectory, and outputs the resulting target rotation angles as position commands to the motor control unit.

[0087] The motor control unit receives position commands for motors 21, 31, 511, and 512, as well as detection signals from each encoder. It performs feedback control to ensure that the rotation angles of motors 21, 31, 511, and 512 match the target rotation angles, and outputs control signals to each motor driver. Furthermore, when driving at least some of the motors, the motor control unit also receives detection signals from the inertial sensor element 81. The motor control unit, upon receiving detection signals from the inertial sensor element 81, uses the detection signals from at least some of the encoders and the detection signals from the inertial sensor element 81 to calculate a feedback value that cancels out vibration components, and performs the feedback control described above.

[0088] Motor drivers are provided for each motor 21, 31, 511, and 512, and operate based on control signals from the motor control unit. Each motor driver has an inverter circuit including a switching element, which converts DC current to AC current using PWM control and supplies AC current to each motor 21, 31, 511, and 512 to drive them.

[0089] For example, to describe the driving of motor 31, the motor control unit receives position commands for motor 31, as well as detection signals from the encoders of each motor 21, 511, and 512, and from the inertial sensor 8. These detection signals are used to calculate a feedback value.

[0090] The motor control unit performs feedback control using a feedback value so that the rotation angle of the motor 31, calculated from the detection signal of the motor 31's encoder, matches the target rotation angle of the motor 31, and outputs a control signal to the motor driver of the motor 31.

[0091] The motor driver of motor 31 drives motor 31 based on the control signal from the motor control unit. By using these feedback values ​​to drive each of the motors 21, 31, 511, and 512 of the robot arm 10, vibration damping control can be performed on the first arm 120, the second arm 130, and the work head 40 based on the values ​​detected by the inertial sensor 8.

[0092] Although only one motor control unit is provided in the control unit 71, the motor control unit is not limited to this, and multiple motor control units may be provided. If multiple motor control units are provided, each motor control unit may correspond to one of the motors 21, 31, 511, and 512. Furthermore, the motor control unit when driving motor 31 may be configured so that the detection signal from the encoder of motor 21 is not input. In that case, the motor control unit calculates a feedback value using the detection signals from the encoder of motor 31 and the inertial sensor 8.

[0093] However, the configuration is not limited to this, and the control unit 71 can be configured to perform vibration damping control on one or any two or more combinations of the first arm 120, the second arm 130, and the work head 40 based on the detected value of the inertial sensor 8.

[0094] For example, the control unit 71 may be configured to perform vibration damping control only on the first arm 120 based on the detected value of the inertial sensor 8. In other words, the feedback value may be used only to drive the motor 21.

[0095] Furthermore, the control unit 71 may be configured to perform vibration damping control only on the second arm 130 based on the detected value of the inertial sensor 8. In other words, the feedback value may be used to drive only the motor 31.

[0096] Furthermore, the control unit 71 may be configured to perform vibration damping control only on the work head 40 based on the detected value of the inertial sensor 8. That is, the feedback value may be used to drive only the shaft lifting motor 511 and the shaft rotation motor 512 of the drive unit 50. Also, when performing vibration damping control on the work head 40, the feedback value may be used to drive only one of the shaft lifting motor 511 and the shaft rotation motor 512.

[0097] Furthermore, the control unit 71 may be configured to perform vibration damping control only on the first arm 120 and the second arm 130 based on the detected values ​​of the inertial sensor 8. In other words, the feedback values ​​may be used only to drive the motor 21 and the motor 31.

[0098] Furthermore, the control unit 71 may be configured to perform vibration damping control only on the first arm 120 and the work head 40 based on the detected value of the inertial sensor 8. In other words, the feedback value may be used only to drive the motor 21, the axial lifting motor 511, and the axial rotation motor 512.

[0099] Furthermore, the control unit 71 may be configured to perform vibration damping control only on the second arm 130 and the work head 40 based on the detected value of the inertial sensor 8. In other words, the feedback value may be used only to drive the motor 31, the axial lifting motor 511, and the axial rotation motor 512.

[0100] By performing vibration damping control as described above, the ceiling-mounted robot 1 can improve the positional accuracy of its work and perform high-precision tasks.

[0101] The memory unit 72 stores various programs and other data executed by the control unit 71. Examples of the memory unit 72 include configurations that include volatile memory such as RAM (Random Access Memory), non-volatile memory such as ROM (Read Only Memory), and removable external storage devices.

[0102] The communication unit 73 transmits and receives signals between the various parts of the ceiling-mounted robot 1 and the control device 7 using an external interface such as a wired LAN (Local Area Network) or wireless LAN. In this case, communication may be performed via a server (not shown) or via a network such as the Internet.

[0103] As described above, the ceiling-mounted robot 1 and ceiling-mounted robot system 100 of this embodiment provide the following advantages. The ceiling-mounted robot 1 of this embodiment comprises a base 110, a first arm 120 whose longitudinal end overlaps the base 110 in a plan view, a joint 25 provided on one end of the first arm 120 and serving as a first joint that holds the first arm 120 so as to be rotatable around a first axis J1 relative to the base 110, a second arm 130 whose longitudinal end overlaps the other longitudinal end of the first arm 120 in a plan view, a joint 35 provided on one end of the second arm 130 and serving as a second joint that holds the second arm 130 so as to be rotatable around a second axis J2 parallel to the first axis J1 relative to the first arm 120, and the other longitudinal end of the second arm 130 The first arm 120 includes an operating shaft 41 provided on the side, which rotates around a third axis J3 parallel to the second axis J2, or moves along the third axis J3, and a housing 121 having a bottom plate 1212 as a first plate portion and a top plate 1211 as a second plate portion facing the bottom plate 1212, a motor 31 that rotates the second arm 130 via a transmission mechanism consisting of a belt 32 and a pulley 33, and an inertial sensor 8 supported by the top plate 1211 and provided in a position that overlaps with the motor 31 in a plan view, or on the other end side of the first arm 120 than the motor 31, which detects at least one of angular velocity and acceleration.

[0104] Thus, in this embodiment, the ceiling-mounted robot 1 has the motor 31 positioned on the bottom plate 1212, and the inertial sensor 8 positioned on the top plate 1211 in a position that overlaps with the motor 31 in a plan view, or on the other end of the first arm 120, relative to the motor 31. Therefore, the inertial sensor 8c or inertial sensor 8d is less susceptible to the vibrations of the motor 31 and can accurately detect the vibrations of the first arm 120.

[0105] Furthermore, in this embodiment, the suspended robot 1 has the motor 31 positioned on the base plate 1212 and the inertial sensor 8 positioned on the top plate 1211. In other words, the inertial sensor 8 is located on the base 110 side of the first arm 120. That is, the inertial sensor 8 is located away from the joint 35. Therefore, the inertial sensor 8c is less affected by vibrations of the joint 35 and can accurately detect vibrations of the first arm 120.

[0106] In the ceiling-mounted robot 1 of this embodiment, the bottom plate 1212, which is the first plate section, is positioned on the second arm 130 side, and the top plate 1211, which is the second plate section, is positioned on the base 110 side. Therefore, the inertial sensor 8c or inertial sensor 8d is less susceptible to the vibrations of the motor 31 and can accurately detect the vibrations of the first arm 120.

[0107] In the ceiling-mounted robot 1 of this embodiment, the inertial sensor 8d is located in a plan view on the other end of the first arm 120, relative to the motor 31, and overlaps with the joint portion 35 which serves as the second joint. Therefore, the inertial sensor 8d is less susceptible to vibrations from the motor 31 and can accurately detect vibrations at the tip of the first arm 120.

[0108] The ceiling-mounted robot system 100 of this embodiment comprises the ceiling-mounted robot 1 described above and a control device 7 which acts as a controller for controlling the ceiling-mounted robot 1. Therefore, it is possible to realize a ceiling-mounted robot system 100 that has high operational precision and high industrial value.

[0109] 2. Embodiment 2 Figure 6 is a side view of the ceiling-mounted robot 1 according to Embodiment 2. Figure 7 is a partial cross-sectional view of the ceiling-mounted robot 1 of Figure 6. Figure 8 is a plan view of the ceiling-mounted robot 1 of Figure 6, viewed from the negative Z-axis side.

[0110] Embodiment 2 shows another arrangement example of the inertial sensor 8 shown in Embodiment 1. In the following description, the same reference numerals are used for components identical to those in Embodiment 1, and redundant explanations are omitted.

[0111] In Embodiment 2, the motor 31 of the drive unit 30 is provided on the upper surface 1211a of the top plate 1211 of the first arm 120. The inertial sensor 8 includes an inertial sensor 8e located on the upper surface 1212a of the base plate 1212 in a position that overlaps with the motor 31 in a plan view, and an inertial sensor 8f located on the other end of the first arm 120 in the longitudinal direction, relative to the motor 31. Therefore, the inertial sensors 8e and 8f are less susceptible to the vibrations of the motor 31 and can accurately detect vibrations of the first arm 120.

[0112] Note that it is not necessary for both the inertial sensor 8e and the inertial sensor 8f to be provided; it is sufficient if either one is provided. In Embodiment 2, the top plate 1211 is an example of the first plate portion, and the bottom plate 1212 is an example of the second plate portion.

[0113] As shown in Figures 6 and 8, a group of connectors 6 is provided on the lower surface of the second arm 130 at a position overlapping with the cylindrical portion 132. The group of connectors 6 consists of, for example, power lines for driving the hand 42, various signal lines, and connectors 61, 62, 63, 64, and 65 for connecting various pipes.

[0114] In Embodiment 2, the shaft lifting motor 511 and the shaft rotation motor 512 are provided adjacent to each other along the shorter direction of the second arm 130. Therefore, the arm length of the second arm 130 can be made shorter than in Embodiment 1. Thus, the inertia (moment of inertia) of the second arm 130 rotating around the second axis J2 can be made smaller than in Embodiment 1.

[0115] As described above, the ceiling-mounted robot 1 of Embodiment 2 provides the following effects in addition to the effects of Embodiment 1. The ceiling-mounted robot 1 of Embodiment 2 comprises a base 110, a first arm 120 whose longitudinal end overlaps the base 110 in a plan view, a joint 25 provided on one end of the first arm 120 and serving as a first joint that holds the first arm 120 so as to be rotatable around a first axis J1 relative to the base 110, a second arm 130 whose longitudinal end overlaps the other longitudinal end of the first arm 120 in a plan view, a joint 35 provided on one end of the second arm 130 and serving as a second joint that holds the second arm 130 so as to be rotatable around a second axis J2 parallel to the first axis J1 relative to the first arm 120, and the other longitudinal end of the second arm 130 The first arm 120 includes an operating shaft 41 provided on the side, which rotates around a third axis J3 parallel to the second axis J2, or moves along the third axis J3, and a housing 121 having a top plate 1211 as a first plate portion and a bottom plate 1212 as a second plate portion facing the top plate 1211, a motor 31 that rotates the second arm 130 via a belt 32 and pulley 33 as a transmission mechanism, and an inertial sensor 8 supported by the bottom plate 1212 and provided in a position that overlaps with the motor 31 in a plan view, or on the other end side of the first arm 120 than the motor 31, which detects at least one of angular velocity and acceleration.

[0116] Thus, in the ceiling-mounted robot 1 of Embodiment 2, the motor 31 is positioned on the top plate 1211, and the inertial sensor 8 is positioned on the bottom plate 1212 at a location that overlaps with the motor 31 in a plan view, or at the other end of the first arm 120, relative to the motor 31. Therefore, the inertial sensor 8e or inertial sensor 8f is less affected by the vibration of the motor 31 and can accurately detect the vibration of the first arm 120.

[0117] In the ceiling-mounted robot 1 of Embodiment 2, the top plate 1211, which is the first plate portion, is positioned on the base 110 side, and the bottom plate 1212, which is the second plate portion, is positioned on the second arm side. Therefore, the inertial sensor 8e or inertial sensor 8f is less affected by the vibration of the motor 31 and can accurately detect the vibration of the first arm 120.

[0118] Although embodiments of the ceiling-mounted robot 1 and the ceiling-mounted robot system 100 have been described above, the present invention is not limited to these. Furthermore, each part of the ceiling-mounted robot system 100 can be replaced with any structure capable of performing similar functions. In addition, any structure may be added to the ceiling-mounted robot system 100. Moreover, the present invention may be a combination of some of the features of each embodiment. [Explanation of Symbols]

[0119] 1...Ceiling-mounted robot, 10...Robot arm, 100...Ceiling-mounted robot system, 20...Drive unit, 21...Motor, 22...Belt, 23...Pulley, 25...Joint, 26...Reduction gear, 261...Wave generator, 262...Flex spline, 263...Circular spline, 27...Flange, 28...Hollow tube, 30...Drive unit, 31...Motor, 32...Belt, 33...Pulley, 35...Joint Part 36... Reducer, 361... Wave generator, 362... Flex spline, 363... Circular spline, 37... Flange, 38... Hollow tube, 40... Work head, 41... Operating shaft, 42... Hand, 43... Cover, 50... Drive unit, 51... Motor, 511... Shaft lifting motor, 512... Shaft rotation motor, 52... Belt, 53... Pulley, 54... Lead screw mechanism, 541... Female screw block, 56 ...belt, 57...pulley, 58...spline mechanism, 581...boss block, 6...connector group, 61,62,63,64,65...connector, 7...control device, 71...control unit, 72...memory unit, 73...communication unit, 8,8a,8b,8c,8d,8e,8f...inertial sensor, 81...inertial sensor element, 82...circuit board, 9...frame, 91...top plate, 911...top surface, 912...bottom surface, 913...through hole, 914...through hole, 9 2...workbench, 93...legs, 95...workpiece, 110...base, 11...main body, 12...fittings, 13...base plate, 120...first arm, 121...housing, 1211...top plate, 1211a...top surface, 1211b...bottom surface, 1212...bottom plate, 1212a...top surface, 1212b...bottom surface, 122...cover, 130...second arm, 131...housing section, 132...tube section, 135...cover, J1...first axis, J2...second axis, J3...third axis.

Claims

1. Base and, In a plan view, one end in the longitudinal direction of the first arm overlaps with the base, A first joint is provided on one end of the first arm and holds the first arm so as to be rotatable around a first axis relative to the base, In a plan view, the second arm has one end in the longitudinal direction that overlaps with the other end in the longitudinal direction of the first arm, A second joint is provided on one end of the second arm, and holds the second arm so that it can rotate around a second axis parallel to the first axis relative to the first arm, The second arm is provided on the other end in the longitudinal direction and includes a shaft that rotates around a third axis parallel to the second axis, or moves along the third axis, The first arm is, A housing having a first plate portion and a second plate portion facing the first plate portion, A motor rotates the second arm via a transmission mechanism, The system includes an inertial sensor supported by the second plate, positioned in a plan view to overlap with the motor, or positioned on the other end side of the first arm relative to the motor, which detects at least one of angular velocity and acceleration. Ceiling-mounted robot.

2. The first plate portion is positioned on the second arm side, and the second plate portion is positioned on the base side. The ceiling-mounted robot according to claim 1.

3. The first plate portion is positioned on the base side, and the second plate portion is positioned on the second arm side. The ceiling-mounted robot according to claim 1.

4. The inertial sensor is provided in a plan view on the other end of the first arm, relative to the motor, and at a position that overlaps with the second joint. The ceiling-mounted robot according to claim 1.

5. The inertial sensor is located in a position that overlaps with the motor in a plan view, and is positioned closer to the base than the motor. The ceiling-mounted robot according to claim 1.

6. A ceiling-mounted robot according to any one of claims 1 to 5, The system includes a controller for controlling the aforementioned ceiling-mounted robot, Ceiling-mounted robot system.

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