JP6502115B2 - Articulated Robot with Link Actuator - Google Patents

Description

  The present invention relates to a multi-joint robot having six or more degrees of freedom using a link operating device used for a device requiring a high speed, high accuracy, and a wide operating range such as a medical device or an industrial device or a robot coexisting with a person. About.

  Patent documents 1 and 2 propose multi-joint robots used for devices that require high speed, high accuracy, and a wide operating range such as medical devices and industrial devices, and robots that coexist with people. The articulated robot of Patent Document 1 is configured by combining a mechanism with one rotation degree of freedom. In the articulated robot of Patent Document 2, a link actuation device with two rotational degrees of freedom is used.

JP 2005-329521 A U.S. Patent No. 6,658,962

  The articulated robot of Patent Document 1 has a configuration in which all the joints have one rotational degree of freedom, so when, for example, the articulated robot collides with a person or a thing, there is a direction that makes it difficult to detect the collision. There's a problem. In addition, even if the attitude of the end effector mounted on the tip is slightly changed, it is necessary to drive a plurality of motors, and there is a problem that fine work can not be performed.

  The articulated robot of Patent Document 2 can solve the safety problem by providing a link actuation device capable of smooth rotation and two degrees of freedom. However, there is a problem that the drive mechanism portion of the link actuating device protrudes outward, the entire device becomes large, and interference with the projecting portion narrows the operating range. In addition, it is expected that the load on the link actuating device is large and it is impossible to carry out fine work.

  The object of the present invention is to provide a multi-joint robot using a link operating device which has a wide range of motion, can be fine-grained quick motion, is highly safe in motion, and is suitable for use at work sites where people coexist It is to be.

An articulated robot using a link actuation device according to the present invention has a base unit and an articulated arm installed on the base unit, and the articulated arm includes a plurality of arm portions from the proximal side to the distal side. Are arranged in series, and the base unit and the most proximal arm, and the adjacent arms are mutually connected via a joint so as to be relatively displaceable, and the end effector mounted on the most distal arm A multi-joint robot with six or more degrees of freedom that performs tasks using
At least one joint unit of the plurality of joint units includes a link operating device that relatively rotates the arm units on both sides of the joint unit around two orthogonal axes,
This link actuation device comprises three sets of distal link hubs fixed to the distal end arm portion relative to the proximal end link hub fixed to the proximal end arm portion of the two arm portions. The posture is changeably connected via the above link mechanism, and each link mechanism is provided with a proximal end and a distal end whose one end is rotatably coupled to the proximal end link hub and the distal end link hub. An end link member on the side and a center link member whose both ends are rotatably connected to the other end of the end link members on the proximal end side and the distal end side, respectively, of the three or more sets of link mechanisms A drive source for attitude control that arbitrarily changes the attitude of the distal end side link hub with respect to the proximal end side link hub in the two or more sets of link mechanisms,
The basic configuration is that this attitude control drive source is disposed in a housed state inside the arm portion to which the link hub on the proximal end side is fixed.

  The link actuating device has a proximal end link hub, a distal end link hub, and three or more sets of link mechanisms, and the distal end link hub can rotate about two orthogonal axes with respect to the proximal end link hub. Constitute a two-degree-of-freedom mechanism. This two-degree-of-freedom mechanism can widen the movable range of the distal end side link hub while being compact. For example, the maximum bending angle of the central axis of the proximal link hub and the central axis of the distal link hub is about ± 90 °, and the pivot angle of the distal link hub relative to the proximal link hub is It can be set in the range of 0 ° to 360 °. By using the link actuating device for at least one joint of a plurality of joints, smooth operation without singularity is possible in the operation range of 90 ° in bending angle and 360 ° in turning angle, and fine motion of wood realizable.

  Since the attitude control drive source of the link actuating device is disposed in the housed state inside the arm portion to which the link hub on the proximal end side is fixed, the protrusion of the articulated robot is reduced, and a compact configuration can be realized. Further, since the interference between the arms of the articulated arm can be reduced, the movable range can be widened. In addition, the fewer protrusions, the overall safety of the device is improved and can be used at work sites that coexist with people.

In the present invention, when the attitude control drive source is a rotary actuator that generates a rotational force, each attitude control drive source is provided with torque detection means for detecting the torque applied to the attitude control drive source, and this torque detection is performed. A load estimation means may be provided for estimating the load acting on the tip end side link hub from the detection result of the means.
Thereby, when an unexpected load is applied to the articulated robot, for example, when it collides with a person or a thing, this can be detected. Since each attitude control drive source is provided with torque detection means, external forces from various directions can be detected. Therefore, when an unexpected load is applied, it is possible to take an evasion operation such as stopping the operation, which is safe.
By providing torque detection means in the attitude control drive source, it is possible to estimate the load acting on the link hub on the tip side without separately providing a sensor for load detection, making the articulated robot compact and reducing the cost. Lead to In addition, since it is configured to move smoothly in all directions without singular points within the working range of the link actuation device, even when a load is applied to the link hub on the tip end side from various directions, it is assured that the attitude control drive source The torque is transmitted and an accurate load can be estimated.

In the present invention, when the attitude control drive source is a rotary actuator that generates a rotational force, the attitude control drive source is installed such that its output shaft is parallel to the central axis of the proximal end link hub. And the rotational force of the drive source for attitude control is transmitted to the end link member on the proximal end side via an axis orthogonal type reduction gear in which the input side axis and the output side axis are orthogonal to each other, and the drive for attitude control It is preferable that the source and the axially orthogonal type reduction gear be disposed on the inner diameter side of the rotational couple of the proximal end link hub and the proximal end link member.
The central axis of the link hub is the point at which the central axis of each rotational pair of the link hub and the end link member and the central axis of each rotational pair of the end link member and the central link member intersect When referred to as the spherical link center of the link hub, it is a straight line passing through the spherical link center and intersecting at right angles with the central axis of the rotation couple of the link hub and the end link member.
With this configuration, the drive mechanism portion including the attitude control drive source, the axis orthogonal reduction gear, and the like can be made compact in the radial direction, and the attitude control drive source can be easily accommodated inside the arm portion.

In the present invention, at least one arm portion of the plurality of arm portions is a shaft in which a proximal end member and a distal end member respectively disposed at the proximal end and the distal end of the arm portion are connected by a plurality of shafts. Ru arm portion der of-linked.
The shaft-connected arm portion can be reduced in weight because there is space inside. Further, when the link actuation device is installed in the shaft connection type arm portion, it is easy to dispose the attitude control drive source of the link actuation device inside the shaft connection type arm portion.

  The shaft-connected arm portion may be a proximal end side arm portion of a joint portion including the link actuation device. In this case, if the distal end member of the shaft-connected arm is the link hub on the proximal end side of the link actuator, the shaft-connected arm and the link actuator share members. Thus, the number of parts can be reduced, and lightness and compactness can be realized.

In the present invention, the arm portion of the shaft coupling type is arm portion of the base end side of the joint portion consisting of the link actuator, the number and the attitude control drive source of the shaft of the arm portion of the shaft-linked number and are the same, you place the shaft one by one between adjacent said attitude control drive source.
In addition, a through hole for wiring is provided in the base end member which is the tip end member of the link hub on the base end side. The plurality of shafts may be circumferentially arranged around the through hole. With this configuration, it is possible to achieve balance in weight and to allow wiring and the like to pass through the space formed at the center of the arm portion.

In the present invention, in the case where the articulated arm has n arm units arranged in series from the proximal side to the distal side, an (n-1) arm unit and an n-th arm unit from the proximal side The joint to be connected or the joint to connect the n-th arm from the proximal side to the end effector may be a joint consisting of the link actuation device.
In this configuration, when the articulated arm of this articulated robot is regarded as a human arm, a link operation device with two degrees of freedom capable of movement close to the wrist joint is provided at a location corresponding to the wrist joint. Since the joints are arranged, the load acting on the link actuating device is small, and high-speed and fine-grained operation is possible.

In the present invention, it is preferable to install two of the articulated arms on one base unit.
This makes it possible for a person to perform work with both hands.

It is preferable that the two proximal arms of the two articulated arms be disposed on the mutually symmetrical planes of the base unit.
With this configuration, it becomes a shape of a two-arm robot similar to a human, and can perform work similar to a human. In addition, when the articulated robot malfunctions, a person can enter the space where the articulated robot has been removed and substitutes for work, thereby preventing a significant reduction in productivity.

An articulated robot using a link actuation device according to the present invention has a base unit and an articulated arm installed on the base unit, and the articulated arm includes a plurality of arm portions from the proximal side to the distal side. Are arranged in series, and the base unit and the most proximal arm, and the adjacent arms are mutually connected via a joint so as to be relatively displaceable, and the end effector mounted on the most distal arm An articulated robot with six or more degrees of freedom that performs tasks using at least one joint of the plurality of joints, the arms on both sides of the joints are relative to each other around two orthogonal axes It consists of a link actuator which rotates, and this link actuator is an arm part by the side of the tip of a link hub by the side of a proximal end fixed to an arm by the side of a proximal end among the arms of the both sides The fixed distal link hub is changeably connected via three or more sets of link mechanisms, and each link mechanism has one end connected to the proximal link hub and the distal link hub. Proximal and distal end link members rotatably connected to each other, and a central link member whose both ends are rotatably connected to the other ends of the proximal and distal end end link members, respectively. An attitude control drive source for arbitrarily changing the attitude of the distal end side link hub with respect to the proximal end side link hub in at least two of the three or more sets of link mechanisms The drive source for attitude control is disposed in the housed state inside the arm portion to which the link hub on the proximal end side is fixed , and at least one arm portion of the plurality of arm portions is the arm portion. With the proximal end of It is a shaft connection type arm unit in which a proximal end member and a distal end member arranged at each end are connected by a plurality of shafts, and the shaft connection type arm is a base of a joint unit including the link actuation device. The arm portion on the end side, wherein the number of shafts of the shaft-connected arm portion is the same as the number of attitude control drive sources, and the shaft is interposed between the attitude control drive sources adjacent to each other. Since each through hole for wiring is provided in the base end member which becomes the tip end member of the link hub on the base end side , the movable range is wide, and the fine motion can be performed quickly, and the safety of operation is achieved. Suitable for use at work sites that coexist with people.

It is a figure which shows schematic structure of the articulated robot concerning one Embodiment of this invention. It is the elements on larger scale of FIG. 1 which fractured and represented one part. It is the figure which abbreviate | omitted a part of link operation device of the multi-joint robot. It is a perspective view of one state of the parallel link mechanism of the link operating device. It is a perspective view of the different state of the same parallel link mechanism. It is sectional drawing of the link hub of the proximal end of the parallel link mechanism, the end part link member of a proximal end, etc. FIG. It is the figure which expressed one link mechanism of the parallel link mechanism with a straight line. It is a figure which shows schematic structure of the articulated robot concerning other embodiment of this invention. It is a figure which shows schematic structure of the articulated robot concerning further another embodiment of this invention. It is a figure which shows schematic structure of the articulated robot concerning further another embodiment of this invention.

An articulated robot using a link actuation device according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a view showing a schematic configuration of this articulated robot. The articulated robot 1 is composed of a base unit 2 and an articulated arm 3 installed on the base unit 2, and the end of the articulated arm 3 performs an operation on a workpiece (not shown). The effector 4 is mounted. In this example, the base unit 2 is installed on the installation surface 5 formed of a horizontal surface. The base unit 2 incorporates a controller 6 for controlling the operation of the articulated robot 1. The controller 6 may be installed outside the base unit 2.

  In the articulated arm 3, a plurality (four in the example shown) of arm portions 11 to 14 are arranged in series from the proximal end side to the distal end side, and the proximal end side arm portion 11 with the base unit 2, Adjacent arm portions 11 to 14 are mutually connected to be relatively displaceable via joint portions 21 to 24, respectively. The end effector 4 is disposed at the most distal arm 14. In the following description, the arm portions 11 to 14 are referred to as “first arm portion 11”, “second arm portion 12”,. It will be called "first joint 21", "second joint 22", ... in order from the proximal side.

  The first joint portion 21 connecting the base unit 2 and the first arm portion 11 has the first arm portion 11 relative to the base unit 2 around the rotation axis 7 orthogonal to the installation surface 5 It consists of a rotating mechanism to rotate. The rotational drive of the first arm portion 11 is performed by a drive source 21 a such as a motor provided in the base unit 2.

  A second joint 22 connecting the first arm 11 and the second arm 12 is a second arm relative to the first arm 11 around the rotation axis 8 parallel to the installation surface 5. It consists of a rotation mechanism which makes part 12 rotate relatively. The rotational drive of the second arm unit 12 is performed by a drive source 22 a such as a motor provided in the first arm unit 11.

  A third joint 23 connecting the second arm 12 and the third arm 13 is a second arm 12 around a rotation axis 9 parallel to the rotation axis 8 of the second joint 22. The third arm 13 is rotated relative to the rotation mechanism. The rotational drive of the third arm unit 13 is performed by a drive source 23 a such as a motor provided in the second arm unit 12.

  The fourth joint unit 24 connecting the third arm unit 13 and the fourth arm unit 14 is a link with two degrees of freedom for changing the posture of the fourth arm unit 14 with respect to the third arm unit 13 It consists of an operating device.

The link actuation device that is the fourth joint unit 24 will be described.
As shown in FIG. 2 and FIG. 3, the link actuation device comprises a parallel link mechanism 30 and an attitude control drive source 31 for operating the parallel link mechanism 30. FIGS. 4 and 5 are perspective views showing only the parallel link mechanism 30 in a state different from each other. As shown in FIGS. 2 to 5, the parallel link mechanism 30 is configured such that the link hub 33 on the distal end side is connected to the proximal end link hub 32 via the three sets of link mechanisms 34 so that the posture can be changed. . In FIGS. 2 and 3, only one set of link mechanism 34 is shown. The number of link mechanisms 34 may be four or more.

  Each link mechanism 34 is composed of a proximal end link member 35, a distal end link member 36, and a central link member 37, and forms a four-bar linkage linkage consisting of four rotational couples. The proximal and distal end link members 35 and 36 are L-shaped, and one end thereof is rotatably connected to the proximal link hub 32 and the distal link hub 33, respectively. The central link member 37 is rotatably connected at its both ends to the other end of the end link members 35 and 36 on the proximal end side and the distal end side.

  The parallel link mechanism 30 is a structure in which two spherical link mechanisms are combined, and each pair of rotations of the link hubs 32, 33 and the end link members 35, 36, and the end link members 35, 36 and the central link member 37. The central axes of each rotation pair intersect at the respective spherical link centers PA, PB (FIG. 3) on the proximal side and the distal side. Further, on the base end side and the tip end side, the rotational pairs of the link hubs 32, 33 and the end link members 35, 36 and the distances from the respective spherical link centers PA, PB are also the same. The distances from the respective rotational pairs of the central link member 36 and the central link member 37 and the respective spherical link centers PA and PB are also the same. The central axes of the rotational pairs of the end link members 35, 36 and the central link member 37 may have a crossing angle γ (FIG. 3) or may be parallel.

  FIG. 6 is a cross-sectional view of the proximal end side link hub 32 and the proximal end side link member 35 etc., and in the figure, the proximal end side link hub 32 and the proximal end side link member 35 are shown. The relationship between the central axis O1 of each rotation pair and the spherical link center PA is shown. The positional relationship between the distal end side link hub 33 and the distal end side end link member 36 is also the same as in FIG. 6 (not shown). In the illustrated example, the central axis O1 of each rotational pair of the link hubs 32, 33 and the end link members 35, 36, and the central axis O2 of each rotational pair of the end link members 35, 36 and the central link member 37. The angle α formed by the two is 90 °, but the angle α may be other than 90 °.

  The three sets of link mechanisms 34 have the same geometrical shape. The geometrically identical shape is, as shown in FIG. 7, a geometric model in which each link member 35, 36, 37 is represented by a straight line, that is, represented by each rotation pair and a straight line connecting these rotation pairs. The model is said to have a shape in which the proximal end portion and the distal end portion with respect to the central portion of the central link member 37 are symmetrical. FIG. 7 is a diagram representing a set of link mechanisms 34 by straight lines. The parallel link mechanism 30 of this embodiment is a rotationally symmetric type, and includes the proximal end link hub 32 and the proximal end link member 35, and the distal end link hub 33 and the distal end link member 36. The positional relationship is rotationally symmetrical with respect to the center line C of the central link member 37. The central portion of each central link member 37 is located on a common orbital circle D.

  In the proximal end side link hub 32, the distal end side link hub 33, and the three sets of link mechanisms 34, the free end link hub 33 is rotatable about two orthogonal axes with respect to the proximal end link hub 32 The degree mechanism is configured. In other words, the link hub 33 on the distal end side with respect to the link hub 32 on the proximal end side is a mechanism whose attitude can be freely changed in two degrees of freedom. Although this two-degree-of-freedom mechanism is compact, the movable range of the distal end link hub 33 with respect to the proximal end link hub 32 can be taken wide.

  For example, a straight line passing through the spherical link centers PA, PB and intersecting at right angles with the central axis O1 (FIG. 6) of each rotational couple of the link hubs 32, 33 and the end link members 35, 36 is the central axis of the link hubs 32, 33. In the case of QA and QB, the maximum value of the bending angle θ (FIG. 7) between the central axis QA of the proximal link hub 32 and the central axis QB of the distal link hub 33 is about ± 90 °. it can. Further, the pivot angle φ (FIG. 7) of the distal end side link hub 33 with respect to the proximal end side link hub 32 can be set in the range of 0 ° to 360 °. The bending angle θ is a vertical angle at which the central axis QB of the distal end link hub 33 is inclined with respect to the central axis QA of the proximal end link hub 32, and the pivot angle φ is the proximal end link hub It is a horizontal angle at which the central axis QB of the link hub 33 on the distal end side is inclined with respect to the central axis QA of 32.

  The posture change of the distal end side link hub 33 with respect to the proximal end side link hub 32 is a line of rotation about the intersection point O of the central axis QA of the proximal end side link hub 32 and the central axis QB of the distal end side link hub 33 It will be. 4 shows a state in which the central axis QA of the proximal link hub 32 and the central axis QB of the distal link hub 33 are on the same line, and FIG. 5 shows the central axis QA of the proximal link hub 32. On the other hand, the central axis QB of the distal end link hub 33 has a certain operating angle. Even if the attitude changes, the distance L (FIG. 7) between the spherical link centers PA and PB on the proximal end side and the distal end side does not change.

  In this parallel link mechanism 30, the angles of the central axes O1 of the rotational pairs of the link hubs 32, 33 and the end link members 35, 36 in each link mechanism 34 and the lengths from the spherical link centers PA, PB are equal to each other, The central axes O1 of the rotational pairs of the link hubs 32, 33 and the end link members 35, 36 of each link mechanism 34, and the central axes O2 of the rotational pairs of the end link members 35, 36 and the central link member 37 The geometrical shapes of the end link member 35 at the proximal end side and the end link member 36 at the distal end side are equal to each other at the end side and the tip side and intersect the spherical link centers PA and PB. When the shape is the same on the distal end side on the proximal end side, the angular positional relationship between the central link member 37 and the end link members 35 and 36 with respect to the plane of symmetry of the central link member 37 If it is made the same on the proximal side and the distal side, the link hub 32 on the proximal side and the end link member 35 on the proximal side, the link hub 33 on the distal side, and the end on the distal side are geometrically symmetrical. The link member 36 moves in the same manner.

  As shown in FIGS. 2 to 5, the link hub 32 on the proximal end side is composed of a proximal end member 40 and three rotary shaft connecting members 41 provided integrally with the proximal end member 40. The proximal member 40 forms a part of the third arm 13 as will be described later. The base end member 40 has a circular through hole 40a at the center, and three rotation shaft connecting members 41 are arranged at equal intervals in the circumferential direction around the through hole 40a. The center of the through hole 40 a is located on the central axis QA of the proximal link hub 32. A rotational shaft 42 (see FIGS. 4 and 5) whose axial center intersects with the central axis QA of the link hub 32 on the proximal side is rotatably connected to each rotational shaft connecting member 41. One end of the proximal end side end link member 35 is connected to the rotation shaft 42.

  As shown in FIG. 6, the rotary shaft 42 is rotatably supported by the rotary shaft connecting member 41 via two bearings 43. The bearing 43 is, for example, a ball bearing such as a deep groove ball bearing or an angular ball bearing. These bearings 43 are installed in the inner diameter hole 44 provided in the rotary shaft connecting member 41 in a fitted state, and fixed by a method such as press fitting, bonding, caulking or the like. The types and installation methods of the bearings provided in the other rotation pairs are the same.

  The rotary shaft 42 has one end of a proximal end side end link member 35 and a sector-shaped bevel gear 45 which is one component of the post-axial orthogonal type reduction gear 77 so as to rotate integrally with the rotary shaft 42. Are combined. Specifically, a notch 46 is formed at one end of the proximal end side end link member 35, and a rotary shaft connecting member is provided between the inner and outer rotary shaft support portions 47 and 48 which are both sides of the notch 46 41 are arranged. The bevel gear 45 is disposed in contact with the inner surface of the inner rotation shaft support 47. Then, the rotary shaft 42 is from the inside, a through hole formed in the bevel gear 45, a through hole formed in the inner rotary shaft support portion 47, an inner ring of the bearing 43, and a through hole formed in the outer rotary shaft support portion 48. The bevel gear 45, the inner and outer rotary shaft support portions 47 and 48, and the inner ring of the bearing 43 are inserted by the holes in order and the nut 50 screwed to the head portion 42a of the rotary shaft 42 and the screw portion 42b of the rotary shaft 42. Each sandwiches and bonds them together. Spacers 51 and 52 are interposed between the inner and outer rotary shaft support portions 47 and 48 and the bearing 43, and a preload is applied to the bearing 43 when the nut 50 is screwed on.

  The rotating shaft 55 is coupled to the other end of the proximal end side end link member 35. The rotating shaft 55 is rotatably coupled to one end of the central link member 37 via two bearings 53. Specifically, a notch 56 is formed at the other end of the end link member 35 on the proximal end side, and a central link member is provided between the inner and outer rotary shaft support portions 57 and 58 which are both sides of the notch 56 One end of 37 is placed. Then, the rotary shaft 55 is inserted from the outside in the order of the through hole formed in the outer rotary shaft support 58, the inner ring of the bearing 53, and the through hole formed in the inner rotary shaft support 57. The inner and outer rotary shaft support portions 57 and 58 and the inner ring of the bearing 53 are respectively sandwiched by the head 55a and the nut 60 screwed to the screw portion 55b of the rotary shaft 55, and these are coupled to each other. Spacers 61 and 62 are interposed between the inner and outer rotary shaft support portions 57 and 58 and the bearing 53, and a preload is applied to the bearing 53 when the nut 60 is screwed on.

  As shown in FIGS. 4 and 5, the link hub 33 on the distal end side has a distal end member 70 fixed to the fourth arm portion 14 (FIG. 2) and circumferentially equidistantly disposed on the inner surface of the distal end member 70. It is comprised by three provided rotating shaft connection members 71. The center of the circumference on which each rotary shaft connecting member 71 is disposed is located on the central axis QB of the link hub 33 on the tip side. To each of the rotary shaft connecting members 71, a rotary shaft 73 whose shaft center intersects with the central axis QB of the link hub 33 at the tip end side is rotatably connected. One end of an end link member 36 on the tip end side is connected to the rotation shaft 73 of the link hub 33 on the tip end side. A rotating shaft 75 rotatably connected to the other end of the central link member 37 is connected to the other end of the end link member 36 on the distal end side. The rotary shaft 73 of the link hub 33 on the tip end side and the rotary shaft 75 of the central link member 37 are, similarly to the rotary shafts 42 and 55, respectively, a rotary shaft connecting member 71 and two bearings (not shown). The other end of the central link member 37 is rotatably connected.

As shown in FIGS. 2 and 3, the attitude control drive source 31 for operating the parallel link mechanism 30 is disposed on the proximal end member 40 and disposed inside the third arm portion 13. The third arm portion 13 is the “arm portion to which the link hub on the proximal end side is fixed” in the claims. The output shaft 31 a of the attitude control drive source 31 is parallel to the central axis QA of the link hub 32 on the proximal end side. The number of attitude control drive sources 31 is three, the same as the number of link mechanisms 34. The attitude control drive source 31 is a rotary actuator, and a bevel gear 76 attached to the output shaft 31a and a sector bevel gear 45 attached to the rotary shaft 42 of the link hub 32 on the base end side are engaged with each other. . The pair of bevel gears 76 and 45 constitute an axial orthogonal speed reducer 77 in which the input side shaft and the output side shaft are orthogonal to each other. As shown in FIG. 6, the attitude control drive source 31 and the shaft orthogonal type speed reducer 77 are disposed on the inner diameter side of the rotational couple of the link hub 32 on the base end side and the end link member 35 on the base end side. It is done.
In this example, the attitude control drive sources 31 are provided in the same number as the link mechanisms 34, but if at least two of the three link mechanisms 34 are provided with attitude control drive sources 31, The attitude of the distal end link hub 33 relative to the proximal end link hub 32 can be determined.

  The fourth joint unit 24 formed of a link actuation device operates the parallel link mechanism 30 by rotationally driving each attitude control drive source 31. Specifically, when the attitude control drive source 31 is rotationally driven, the rotation is transmitted to the rotation shaft 42 via the orthogonal orthogonal speed reducer 77 composed of a pair of bevel gears 76 and 45, and the link hub 32 on the proximal end side The angle of the end link member 35 on the proximal side with respect to. Thereby, the position and posture of the distal end link hub 33 with respect to the proximal end link hub 32 are determined. Here, the axially orthogonal reducer 77 is composed of a pair of bevel gears 76 and 45. In addition, a mechanism using a worm gear and a pinion gear, a mechanism using a hypoid gear (trade name), or the like may be used.

  In FIG. 1, each attitude control drive source 31 is provided with torque detection means 78 for detecting the torque applied to the attitude control drive source 31. The detection signal of the torque detection means 78 is sent to the load estimation means 79 in the controller 6. The load estimation means 79 estimates the load acting on the link hub 33 on the tip side from the detection results of each torque detection means 78.

  As shown in FIGS. 2 and 3, the third arm portion 13 is a shaft connection in which a proximal end member 91 and a distal end member 92 disposed respectively at the proximal end and the distal end are connected by a plurality of shafts 93. It is an arm part of a mold. The distal end member 92 is the same member as the proximal member 40 constituting the link hub 32 on the proximal side of the link actuation device. As shown in FIG. 6, the number of shafts 93 is the same as the number of attitude control drive sources 31 (3 in this embodiment), and one shaft 93 is disposed between adjacent attitude control drive sources 31. There is. Both the attitude control drive source 31 and the shaft 93 are equally distributed in the circumferential direction.

  In FIGS. 1 and 2, the fourth arm portion 14 is provided with a tip rotation mechanism 80 and supports the end effector 4 via the tip rotation mechanism 80. The tip rotation mechanism 80 has an end effector installation member 80b attached to the rotation shaft of a rotation drive source 80a such as a motor, and the end effector 4 is fixed to the end effector installation member 80b. As the end effector 4, for example, a hand, a welder, an applicator, or the like is used, but is not limited thereto.

  The articulated robot 1 has one degree of freedom of the first joint portion 21 formed of a rotation mechanism, one degree of freedom of the second joint portion 22 formed of a rotation mechanism, and one degree of freedom of a third joint portion 23 formed of a rotation mechanism. The second joint 24 has a total of six degrees of freedom, that is, two degrees of freedom of the fourth joint unit 24 formed of a link actuation device, and one degree of freedom of the distal end rotation mechanism 80 provided on the fourth arm unit 14. With a configuration of six degrees of freedom, it is possible to be close to human hand movement.

  In particular, by using the link actuating device for one joint portion 24 of the plurality of joint portions 21 to 24, smooth operation without a singular point within the operation range of a folding angle of 90 ° and a turning angle of 360 ° It becomes possible and can realize fine grained operation. The fine-grained motion is, for example, a motion such as a text writing motion or a motion using snaps, in particular, a motion for moving a human wrist joint center, but is not limited to these motions. By using the link actuating device, the joint portion 24 can be made compact while having two degrees of freedom.

In this embodiment, the fourth joint 24 between the most distal end arm (fourth arm) 14 and the second arm (third arm) 13 from the distal end side performs link operation. It is a joint consisting of a device. In other words, in the articulated arm 3 having n arms 11 to 14 arranged in series from the proximal end to the distal end, the (n-1) arm 13 and the n-th arm 14 from the proximal end The joint 24 connecting the two is a joint consisting of a link actuation device.
In this configuration, when the articulated arm 3 of the articulated robot 1 is regarded as a human arm, a link actuation device with two degrees of freedom capable of movement close to the wrist joint can be provided at a location corresponding to the wrist joint. Since the joints 24 are disposed, the relationship between the movement of the joints 21 to 24 and the movement of the end effector 4 can be easily imagined, and the operability is good. In addition, the load acting on the link actuating device is small, and high-speed and fine-grained operation is possible.
The same action and effect as described above can be obtained even when the joint that connects the n-th arm 14 and the end effector 4 from the proximal end side is a joint made of a link actuation device.

  A torque detection means 78 for detecting the torque applied to each attitude control drive source 31 and a load estimation means 79 for estimating the load acting on the tip end link hub 33 from the detection result 78 of the torque detection means are provided. Therefore, when an unexpected load is applied to the articulated robot 1, for example, when it collides with a person or a thing, this can be detected. Therefore, when an unexpected load is applied, it is possible to take an evasion operation such as stopping the operation, which is safe.

  By providing the torque detection means 78 in the attitude control drive source 31, it is possible to estimate the load acting on the link hub 33 on the tip end side without separately providing a sensor for load detection. Leading to cost reduction and In addition, since load is applied to the distal end side link hub 33 from various directions, since there is no singular point and the structure can be moved smoothly in all directions within the operation range of the fourth joint unit 24 composed of the link operating device. However, the torque is reliably transmitted to the attitude control drive source 31, and an accurate load can be estimated.

  Since the attitude control drive source 31 is disposed in the housed state within the third arm portion 13 which is a shaft connection type arm portion, the number of projecting portions of the articulated robot 1 is small, and a compact configuration can be realized. . Moreover, since interference of the arm parts 11-14 of the multi joint arm 1 can be reduced if there are few protrusion parts, a movable range can be taken widely. In addition, the fewer protrusions, the overall safety of the device is improved and can be used at work sites that coexist with people.

  By forming the third arm portion 13 as a shaft connection type arm portion, the attitude control drive source 31 can be easily disposed inside the third arm portion 13. In addition, the attitude control drive source 31 is installed so that the output shaft 31a of the attitude control drive source 31 is parallel to the central axis QA of the link hub 32 on the proximal end side. The attitude control drive source 31 and the axis orthogonal type reduction gear are arranged by arranging the type reduction gear 77 on the inner diameter side of the rotation pair of the link hub 32 on the base end side and the end link member 35 on the base end. The drive mechanism section 77 and the like can be made compact in the radial direction, and the attitude control drive source 31 can be easily accommodated inside the third arm section 13.

  The third arm portion 13 which is a shaft connection type arm portion can be reduced in weight because there is a space inside. In addition, since the distal end end member 92 of the third arm portion 13 which is a shaft connection type arm portion is the same member as the proximal end member 40 of the link hub 32 on the proximal end side of the link actuation device, the number of parts is reduced and the weight is reduced.・ Compact can be realized.

  Furthermore, the number of shafts 93 of the third arm 13 which is a shaft-connected arm is the same as the number of attitude control drive sources 31, and the shaft 93 is interposed between the attitude control drive sources 31 adjacent to each other. By arranging each of them, it is possible to achieve balance in weight and to form a space in the center of the arm portion, so that it is possible to pass a wiring or the like through this space.

  FIG. 8 shows another embodiment. The articulated robot 1 is the same as the first embodiment in that it has an articulated arm 3 in which four arm units 11 to 14 are arranged in series, but differs from the first embodiment in the following points.

  That is, the fourth joint unit 24 connecting the third arm unit 13 and the fourth arm unit 14 rotates the fourth arm unit 14 relative to the third arm unit 13 around the rotation axis 10 It consists of a rotating mechanism. The rotational drive of the fourth arm unit 14 is performed by a drive source 24 a such as a motor provided in the third arm unit 13.

  Further, the fourth arm 4 is provided with an end effector support mechanism 81 consisting of a link actuation device, and the end effector 4 is supported via the end effector support mechanism 81. The fourth arm unit 14 is, for example, an arm unit of the shaft connection type, and the drive source 31 for attitude control of the link actuation device is built in the fourth arm unit 14.

  Others are the same as the first embodiment. As in the first embodiment, this articulated robot 1 has a configuration of six degrees of freedom overall, a wide movable range, capable of fine-grained quick motion, high motion safety, and coexists with people Suitable for use at work site.

  FIG. 9 shows still another embodiment. In this articulated robot 1, a second joint unit 22 connecting the first arm unit 11 and the second arm unit 12 is configured by a link actuation device, and the other joint units 21, 23, 24 have a rotation mechanism. It consists of Further, the end effector 4 is supported by a tip rotation mechanism 80 provided to the fourth arm portion 14. Also in this case, as in the first embodiment, the overall configuration is 6 degrees of freedom, the movable range is wide, the fine motion can be performed quickly, the operation safety is high, and the work site coexists with people Suitable for use in

  FIG. 10 shows still another embodiment. The articulated robot 1 has two articulated arms 3 installed on one base unit 2. Specifically, the first arm portions 11 of the two articulated arms 3 are installed on the mutually symmetrical side surfaces of the base unit 2. Each articulated arm 3 has the same configuration as the articulated arm 3 of the articulated robot 1 shown in FIG.

  As described above, by providing two articulated arms 3, an operation that a person performs with both hands is possible. In particular, by arranging the two articulated arms 3 in the plane of symmetry in the base unit 2, the shape of a double arm robot similar to a human can be obtained, and work similar to a human can be performed. In addition, when the articulated robot 1 malfunctions, a person can enter and substitute for the space where the articulated robot 1 has been removed, so that the productivity can be prevented from being greatly reduced.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, the embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

1 ... articulated robot 2 ... base unit 3 ... articulated arm 4 ... end effector 5 ... installation surface 11 ... first arm 12 ... second arm 13 ... third arm (proximal link hub Arm with fixed shaft, arm of shaft connection type)
14 ... 4th arm part 21 ... 1st joint part (rotation mechanism)
22 ... 2nd joint part (rotation mechanism)
23 ... 3rd joint part (rotation mechanism)
24 ... 4th joint part (link actuating device)
Reference Signs List 30 parallel link mechanism 31 attitude control drive source 32 link hub 33 on the base end side link hub 34 on the tip side link mechanism 35 link mechanism 35 end link member on the base end end link member on the tip side 37 central link member 77 orthogonal axis type reduction gear 78 torque detection means 79 load estimation means 91 proximal end member 92 tip end member 93 shaft PA, PB spherical link center QA, QB of link hub Central axis

Claims (8)

A base unit and an articulated arm installed in the base unit, the articulated arm having a plurality of arm portions arranged in series from the proximal end side to the distal end side, and the proximal end side with the base unit The arm unit and the adjacent arm units are connected relative to each other via the joint unit so as to be relatively displaceable, and the articulated robot with six or more degrees of freedom that uses the end effector mounted on the most distal end arm unit And
At least one joint unit of the plurality of joint units includes a link operating device that relatively rotates the arm units on both sides of the joint unit around two orthogonal axes,
This link actuation device comprises three sets of distal link hubs fixed to the distal end arm portion relative to the proximal end link hub fixed to the proximal end arm portion of the two arm portions. The posture is changeably connected via the above link mechanism, and each link mechanism is provided with a proximal end and a distal end whose one end is rotatably coupled to the proximal end link hub and the distal end link hub. An end link member on the side and a center link member whose both ends are rotatably connected to the other end of the end link members on the proximal end side and the distal end side, respectively, of the three or more sets of link mechanisms A drive source for attitude control that arbitrarily changes the attitude of the distal end side link hub with respect to the proximal end side link hub in the two or more sets of link mechanisms,
The attitude control drive source is disposed in a state of being housed inside the arm portion to which the proximal end side link hub is fixed ,
At least one arm unit of the plurality of arm units is a shaft connection type arm in which a proximal end member and a distal end member arranged respectively at the proximal end and the distal end of the arm unit are connected by a plurality of shafts Is a department,
The arm unit of the shaft connection type is an arm unit on the proximal end side of the joint unit including the link actuation device, and the number of shafts of the arm unit of the shaft connection type is the same as the number of drive sources for attitude control. And one of the shafts is disposed between the posture control drive sources adjacent to each other,
A through hole for wiring is provided in a proximal end member which becomes the distal end end member of the proximal end side link hub,
Articulated robot using link actuator.   In the articulated robot using the link actuation device according to claim 1, the attitude control drive source is a rotary actuator that generates a rotational force, and torque applied to the attitude control drive source to each attitude control drive source. A multi-joint robot using a link operating device provided with a torque detection means for detecting the load, and a load estimation means for estimating the load acting on the link hub on the tip end side from the detection result of the torque detection means. The articulated robot according to claim 1 or 2, wherein the attitude control drive source is a rotary actuator that generates a rotational force,
The point at which the center axis of each rotation pair of the link hub and the end link member and the center axis of each rotation pair of the end link member and the center link member intersect is referred to as the spherical link center of the link hub When a straight line passing through the center of the spherical link and intersecting at right angles with the central axis of the rotation couple of the link hub and the end link member is referred to as the central axis of the link hub,
The attitude control drive source is installed such that the output shaft is parallel to the central axis of the proximal end link hub, and the input side shaft and the output side shaft are orthogonal to each other via an axis orthogonal type reduction gear The rotational force of the attitude control drive source is transmitted to the end link member on the base end side, and the attitude control drive source and the axis orthogonal type reduction gear are connected to the link hub on the base end side and the base end side. An articulated robot using a link actuation device disposed on the inner diameter side of a rotation pair with an end link member. The articulated robot using the link actuation device according to any one of claims 1 to 3 , wherein the arm of the shaft connection type is a proximal end arm of a joint portion composed of the link actuation device. The articulated robot, wherein the distal end member of the shaft-connected arm unit is a link hub on the proximal side of the link actuation device. The articulated robot using the link actuation device according to any one of claims 1 to 4 , wherein the articulated arm has n arm portions arranged in series from the proximal end side to the distal end side. A joint that connects the (n-1) arm to the n-th arm from the base end, or a joint that connects the n-th arm from the base to the end effector; Articulated robot which is a joint unit comprising a link actuation device. An articulated robot using a link actuation device according to any one of claims 1 to 5 , wherein the articulated actuator has two articulated arms installed on one of the base units. . 7. The articulated robot using a link actuation device according to claim 6 , wherein the two articulated arms have the most proximal arm portions installed on mutually symmetrical planes of the base unit. Articulated robot using equipment. The articulated robot according to any one of claims 1 to 7, wherein the plurality of shafts use link actuators arranged in the circumferential direction around the through holes. Articulated robot.

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