Robotic arm with articulated joints

Abstract

The present invention relates to a robotic arm having at least two segments (2), the segments being interconnected at one end by a hinge joint (10) such that the segments are pivotable relative to each other about a rotational axis (A), wherein the two segments (2) each comprise at least one joint portion (3) and an adjoining transition portion (4) and extend along a longitudinal direction (L). According to the invention, the transition portion (4) of at least one of the segments (2; 2a) has a circumferential edge (6) which, when viewed in a direction extending transversely to the rotational axis (A) and transversely to the longitudinal direction (L), crosses a parting line (9) present between the two joint portions (3) and extends radially beyond the joint portion (3) of the other segment (2) by a defined distance; wherein the circumferential edge (6) extends beyond the surface of the underlying joint portion (3) of the other segment (2) by a distance of less than 25 millimeters with respect to the rotational axis (A). Furthermore, when viewed in a direction extending transversely to the rotational axis (A) and transversely to the longitudinal direction (L), a section of the circumferential edge (6) extends obliquely with respect to the rotational axis (A).

Description

Field of the Invention

[0001] The present invention relates to a robotic arm having at least two segments that are interconnected by joints that allow the arm to bend. Background Art

[0002] Industrial robots (also known as industrial manipulators) are general-purpose programmable machines for handling, installing, or machining workpieces or objects. There are various different designs of such robots. Single-arm robots are known, for example, from DE10 2015012 959A1 or DE 10 2018 213 499A1. The robots shown therein have multiple segments that are interconnected by articulated joints and rolling joints. The articulated joint allows the associated segment to pivot about a rotational axis, and the rolling joint allows the associated segment to rotate about a longitudinal axis.

[0003] A disadvantage of many known robot structures is that the distance from the rolling joint of one segment to the associated articulated joint is relatively large. As a result, the performance or agility of the robot is lost. Shortening the distance between the rolling joint and the articulated joint can also shorten the overall length of the robot, thereby increasing the overall rigidity.

[0004] Other robot structures achieve a shorter distance between the rolling joint and the articulated joint by directly joining the rolling joint area to the articulated joint area, but this results in an area with a small material cross-section, which adversely affects the rigidity and strength of the robotic arm.

[0005] Therefore, the object of the present invention is to provide a compact, stable, and agile robot with a robotic arm having multiple segments connected by articulated joints and rolling joints.

[0006] According to the present invention, this object is achieved by the features described in claim 1. Other designs of the present invention result from the dependent claims. Summary of the Invention

[0007] A robotic arm having at least two segments is proposed, which are interconnected by articulated joints such that they can pivot relative to each other about a common axis of rotation. These segments each include at one end a joint portion that houses a part of the articulated joint and abuts a curved transition portion, which in turn leads into a connecting arm portion. The segment also extends longitudinally in a direction transverse to the axis of rotation and corresponding to the main extension direction of the robotic arm in the fully extended state of the robotic arm. At least one of the two segments includes a transition portion with a circumferential edge that extends from the joint portion of the segment towards the joint portion of the other segment and, when viewed from a direction transverse to the axis of rotation and transverse to the longitudinal direction, crosses the parting line existing between the two joint portions. The circumferential edge is arranged at a radial distance of less than 25 millimeters from the axis of rotation outside the surface of the underlying joint portion of the other segment. The transition portion of one segment thus overhangs the joint portion of the other segment by a small distance. Additionally, the circumferential edge extends obliquely relative to the axis of rotation at least on one side of the articulated joint when viewed from the aforementioned direction. The robotic arm designed in this way is particularly compact and provides high performance.

[0008] In other words, for the course of the circumferential edge, the following applies: If the articulated joint is viewed from a direction transverse to the axis of rotation and transverse to the longitudinal direction of the respective segment, the circumferential edge extends at least along one section spatially in front of and / or behind the articulated joint. Thus, the point at which it crosses the parting line between the two joint portions lies in front of or behind the articulated joint when viewed from this direction. From this point, the circumferential edge then extends obliquely upwards or downwards (when the axis of rotation is horizontally arranged) spatially in front of the articulated joint until it extends beyond the upper / lower edge of the projection plane of the other joint portion of the articulated joint and extends radially outside the other joint portion, i.e., above or below it.

[0009] The circumferential edge of one segment preferably has a substantially constant radial distance from the surface of the joint portion of the other segment along its course.

[0010] According to a preferred embodiment of the invention, the distance between the circumferential edge of one segment and the surface of the underlying or radially inner joint portion of the other segment is less than 10 millimeters, especially about 1 - 5 millimeters.

[0011] "Joint portion" should in particular refer to the following section of the segment that forms a part of the articulated joint and, for example, houses a part of the motor drive means therein. The articulated joint preferably consists of two adjacent joint portions of two segments, in which a joint mechanism is housed.

[0012] According to an embodiment of the present invention, the circumferential edge extends relative to the axis of rotation at an angle of between 1° and 70°, or between 10° and 50°, preferably between approximately 15° and 30°, at least in the parting line region when viewed from a direction transverse to the axis of rotation and transverse to the longitudinal extension.

[0013] The circumferential edge of the transition portion defines a bottom surface according to the present invention. The bottom surface is V-shaped or parabolic in a top view and has two sides that extend obliquely or intersect with respect to the axis of rotation. These two sides may be symmetric with respect to the vertex of the curve, but they may also extend asymmetrically. The top view is a view seen from a direction in which the maximum extension dimension of the bottom surface appears. It should be noted in this regard that the bottom surface does not have to exist physically, but may be a virtual surface defined by the circumferential edge.

[0014] According to a preferred embodiment of the present invention, these sides of the circumferential edge (when viewed in a top view) extend relative to the axis of rotation at an angle of between 0° and 30°, or between 10° and 30°, preferably between approximately 15° and 25°, at least in the parting line region. The angle between the circumferential edge and the axis of rotation is preferably approximately 15° to 25° at the parting line position.

[0015] The bottom surface of the transition portion of one segment and the surface of the joint portion of another segment located below or radially inward are preferably parallel planes. During the bending movement of the robotic arm, the radial distance between the bottom surface of one segment and the joint portion of the other segment located below preferably remains constant.

[0016] The second segment of a hinge joint is preferably designed in the same manner as the first segment and accordingly has a transition portion that extends from its joint portion towards the joint portion of the first segment, crosses the parting line existing between the two joint portions, and then extends above the first joint portion at a predetermined radial distance. According to an embodiment of the present invention, the transition portion of the second segment has a circumferential edge that is arranged above the surface of the joint portion of the first segment at a radial distance of less than 25 millimeters with respect to the axis of rotation. The transition portion of the second segment thus hangs above the joint portion of the first segment at a very small distance. In addition, the circumferential edge extends obliquely relative to the axis of rotation at least on one side of the hinge joint when viewed from a direction transverse to the axis of rotation and transverse to the rolling axis.

[0017] The hinge joint is preferably designed such that the parting line between the two segments is substantially located at the center of the joint. However, the parting line may also be arranged laterally offset with respect to the center. The parting line is preferably in a plane extending transverse to the axis of rotation.

[0018] According to an embodiment of the present invention, the circumferential edge of the transition portion of the first or second segment extends beyond the parting line and continues as an edge within the joint region of the corresponding segment. The edge run is substantially continuous here, i.e., there are no steps or only steps of a few millimeters, in particular less than 5 millimeters.

[0019] The segments of the robotic arm are preferably designed such that when the robotic arm is in a defined position, a section of the circumferential edge of the first segment and an adjacent section of the circumferential edge of the second segment, which together form a joint, extend substantially parallel. The parallel arrangement of the adjacent sections or edges preferably exists at the following positions of the articulated joint, where the joint is at a terminal stop and the adjacent sections or edges are closest to each other.

[0020] According to a specific embodiment of the present invention, the transition portion between the two segments is formed such that the distance between the transition portions measured circumferentially (with respect to the axis of rotation) in the adjacent circumferential edge regions increases as the distance from the axis of rotation increases. This prevents the user from pinching their fingers when the segments are bent to the maximum extent.

[0021] The transition portion between the two segments of a joint is preferably formed in its circumferential edge region such that a V-shaped gap remains between the transition portions when the segments are bent to the maximum extent. The size of the V-shaped gap is preferably set such that the user does not pinch their fingers between the two segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in detail below with reference to the accompanying drawings, where:

[0023] Figure 1 A decomposition view of a robotic arm having a plurality of segments, which are interconnected by articulated joints and rolling joints;

[0024] Figures 2a - 2d Showing the Figure 1 robotic arm in various views in a fully extended state;

[0025] Figure 3 A schematic view of an articulated joint for explaining the basic principle of the present invention;

[0026] Figure 4 Showing the Figure 1 decomposition view of the articulated joint of the robotic arm;

[0027] Figure 5 Showing the Figure 1 decomposition view of a plurality of segments of the robotic arm;

[0028] Figure 6 A top view showing the bottom surface of the transition portion of a segment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Figure 1 Exploded view showing a robotic arm 1 having a plurality of segments 2, which are interconnected by a plurality of articulated joints 10 and rolling joints 19. The articulated joints 10 respectively permit pivotal movement of the corresponding segments 2 about a rotational axis A, and the rolling joints 19 respectively permit rotational movement of the corresponding segments 2 about a swivel axis B.

[0030] The robotic arm 1 in this embodiment includes exactly eight segments, namely, from bottom to top in sequence: segment G0, which is connected to segment G1 by a rolling joint 19. The latter is pivotally connected to segment G2 by an articulated joint 10. At the upper end of segment G2, there is also provided a rolling joint 19, which connects segment G2 to the next segment G3. The latter is connected to another segment G4 by an articulated joint 10. Segment G4 is connected to segment G5 by a rolling joint 19, and segment G5 is connected to another segment G6 by an articulated joint 10. Segment G6 is finally also connected to segment G7 by a rolling joint 19.

[0031] In the configuration of the robotic arm 1 shown here, the articulated joints 10 and the rolling joints 19 are arranged overlappingly. The rotational axis A of the articulated joint 10 and the swivel axis B of the rolling joint 19 are also perpendicular to each other.

[0032] Segments G1 - G6 respectively include a joint portion 3, in which a part of the corresponding articulated joint 10 is accommodated. Each segment also includes a transition portion 4 and a connecting arm portion 5 that accommodates a part of the corresponding rolling joint 19. Each articulated joint 10 includes two joint portions 3 of adjacent segments 2 arranged side by side in the direction of the rotational axis A. There is a parting line 9 between the two joint portions 3 of an articulated joint 10, which is arranged centrally here. But it can also be arranged laterally offset relative to this center.

[0033] Figures 2a - 2d Showing the Figure 1 robotic arm 1 in a fully extended state. Here, Figure 2a is a view seen from the front, Figure 2b is a view seen from the left side, Figure 2c is a view seen from the rear side, Figure 2d is a view seen from the right side. In the fully extended state of the robotic arm 1 as shown in the figure, the longitudinal direction L of each segment 2 corresponds to the main extension direction of the robotic arm 1.

[0034] The robotic arm 1 shown here imitates the shape of a human arm. The articulated joints 10 can therefore also be referred to as the shoulder joint 12, the elbow joint 13, and the wrist joint 14. Segment G6 is the robot head 15, and for example, tools or sensors that can perform desired actions are fixed on the robot head according to their respective applications.

[0035] As in Figures 2a - 2dAs can be seen, in particular, the structures of the shoulder joint 12 and the elbow joint 13 are very compact and stable. The structural principles of the articulated joints 12 and 13 will be explained in detail below in conjunction with Figure 3 to be explained in detail.

[0036] Figure 3 A schematic view of an articulated joint 10 is shown, which pivotally connects two segments 2a and 2b to each other. Each segment 2a, 2b includes a joint portion 3a, 3b, which houses a part of the joint mechanism of the articulated joint 10, and each segment also includes a transition portion 4a, 4b, which projects beyond the joint portions 3a, 3b of the respective other segment 2a, 2b. At its free end (above or below in the figure), the segments 2a, 2b are connected to the next segment 2 (not shown) by respective rolling joints 19.

[0037] As can be seen in Figure 3 the transition portion 4b of the upper segment 2b extends from the joint portion 3b to the right towards the joint portion 3a of the other segment 2a, crosses the parting line 9 in the direction of the axis of rotation A, and then extends at a defined distance slightly above the joint portion 3a of the segment 2a. The corresponding situation also applies to the transition portion 4a of the other segment 2a, but in the opposite direction. The connecting arms of the two segments 2a, 2b are designated by the reference numeral 5. The segments 2 extend in the longitudinal direction L extending transversely to the axis of rotation A in the illustrated state. The longitudinal direction L and the rolling axis B point in the same direction.

[0038] The transition portions 4a, b of the two segments 2a, 2b each have a circumferential edge 6 on the side facing the axis of rotation A, which extends above the surface of the underlying joint portions 3a, 3b of the respective other segment 2a at a small radial distance of less than 10 mm, preferably about 1 - 4 mm. In other words, the transition portions 4a, 4b of the segments 2a, 2b project beyond the joint portions 3a, 3b of the respective other segment 2a, 2b and hang above them at a small distance.

[0039] If one observes the circumferential edges 6a, 6b from a direction extending transversely to the axis of rotation A and transversely to the longitudinal direction L or the rolling axis B as shown here, the respective circumferential edges 6a, 6b extend obliquely with respect to the axis of rotation A. This has the advantage that the robotic arm 1 is very compact and has high rigidity. The angle β formed by the circumferential edges 6a, 6b with respect to the axis of rotation A, for example, can be between 1° and 70°, preferably between 15° and 30°.

[0040] In the illustrated principle sketch, the circumferential edges 6a, 6b are drawn simplifiedly as straight lines. In reality, they can also be curved. The angle β defined above between the circumferential edges 6a, 6b and the axis of rotation A should therefore exist at least at one position of the circumferential edges 6a, 6b, in particular at the parting line 9.

[0041] It can also be seen in Figure 3 that the circumferential edges 6a, 6b of the transition parts 4a, 4b continue as shell edges 17a, 17b respectively in the joint parts 3a, 3b of the corresponding segments 2a, 2b. The runs of the edges 6, 17 are substantially continuous here, that is, there are no step parts in the runs, or only minor step parts of a few millimeters and especially approximately 1 - 4 millimeters.

[0042] In addition, the segments 2a, 2b are designed in the region of the articulated joint 10 such that, when the articulated joint 10 is in the final position, a section of the circumferential edge 6a of the segment 2a and a section of the shell edge 17b of the other segment 2b extend substantially parallel.

[0043] Instead of the two segments 2a, 2b, only one of the segments 2a, 2b may also have a transition part 4a, 4b with circumferential edges 6a, 6b that extend obliquely. The segments 2a, 2b may be symmetrically formed on the other side of the axis of rotation A (that is, when viewed from the rear in the figure). Or only one of the segments 2a, 2b may be symmetrically designed.

[0044] Figure 4 Two segments 2 designed according to the above principle are shown, which are pivotally connected to each other by an articulated joint 1. Here, in particular, the circumferential edge 6 of the transition part 4 can be clearly seen on the segment 2 shown on the right side in the figure as in the drawing. The transition part 4 also has a bottom surface 7, which is V - shaped or parabolic when viewed in the direction of the rolling axis and has two sides that extend obliquely or converge with respect to the axis of rotation A.

[0045] The bottom surface 7 of one segment 2 and the lower surface of the joint part 3 of the other segment 2 are preferably parallel surfaces. The surface of the joint part 3 can be formed, for example, in a cylindrical shape or a cylindrical barrel shape or a bellows - shaped barrel shape as shown in the figure.

[0046] It can also be clearly seen in Figure 4 how the circumferential edge 6 of the transition part 4 continues as an edge 17 respectively in the joint part 3 region of the corresponding segment 2. The runs of the edges 6, 17 are substantially continuous here.

[0047] If one looks at Figure 2c, it is also possible to see the transition part 4 where two segments 2b and 2c are formed in this way, that is, the distance between the transition parts 4 measured circumferentially (with respect to the rotation axis A) in the adjacent circumferential edge 6 regions increases as the distance from the rotation axis A increases. The transition parts 4 of the adjacent segments 2b and 2c are formed in such a way that when the segments 2b and 2c are bent to the maximum extent, a V-shaped gap 11 remains between the transition parts 4 in the adjacent circumferential edge 6 regions. When the joint 10 moves to the final position, the gap 11 prevents the user from pinching their fingers. The gap 11 is preferably realized in the same or similar way on both sides of the joint 10.

[0048] Figure 5 shows a decomposition view of multiple segments in the shoulder joint 12 and elbow joint 13 regions of the robotic arm 1 in Figure 1 . In particular, the structure of each segment 2 and its position within the robotic arm can be clearly seen here.

[0049] Figure 6 Exemplarily shows the circumferential edge 6 of the bottom surface 7 of the segment 2 of the shoulder joint 12. The circumferential edge 6 of another segment 2 can be designed identically or similarly. As can be seen, the circumferential edge 6 has a V-shaped or parabolic profile with two sides 8 in a top view, and the two sides extend obliquely with respect to the rotation axis A.

[0050] If one draws a tangent 16 to the circumferential edge 6 at the parting line 9 position, the tangent 16 preferably forms an angle α between 0° and 30° with the rotation axis A. Therefore, the sides 8 of the circumferential edge 6 extend at an angle between 0° and 30° with respect to the rotation axis A in the parting line region (in a top view). According to a preferred embodiment, the angle α can be approximately 15° to 25°.

[0051] Each segment 2 is preferably made of metal or plastic. The control device of the robotic arm 1 can be integrated within the robotic arm 1 or arranged externally.

Claims

1. A robotic arm having at least two segments (2), the segments being interconnected at one end by a hinge joint (10) such that the segments can pivot relative to each other about a rotation axis (A), wherein, At least one of the segments (2) extends in the longitudinal direction (L) and includes a joint portion (3) and an adjoining transition portion (4), the transition portion extending from the joint portion (3) of the segment (2) towards the joint portion (3) of another segment (2), wherein the longitudinal direction (L) is a direction perpendicular to the axis of rotation (A) and corresponding to the main extension direction of the robotic arm; at least one of the segments (2) includes a first segment (2; 2a), and the other segment (2) includes a second segment (2; 2b); Characterized in that, the transition portion (4) of at least one of the segments (2) has a circumferential edge (6), which, when viewed from a direction perpendicular to the axis of rotation (A) and perpendicular to the longitudinal direction (L), crosses the parting line (9) existing between the two joint portions (3); the circumferential edge (6) extends outside the surface of the underlying joint portion (3) of the other segment (2) at a distance of less than 25 mm with respect to the axis of rotation (A); and when viewed from the direction perpendicular to the axis of rotation (A) and perpendicular to the longitudinal direction (L), at the position where the circumferential edge crosses the parting line (9), a section of the circumferential edge (6) extends obliquely with respect to the axis of rotation (A).

2. The robotic arm according to claim 1, characterized in that, The circumferential edge (6) has a substantially constant radial distance from the surface of the other segment (2) along its course.

3. The robotic arm according to claim 1, wherein, When viewed from the direction perpendicular to the axis of rotation (A) and perpendicular to the longitudinal direction (L), the circumferential edge (6) extends at an angle (β) between 1° and 70° with respect to the axis of rotation (A) at least in the region of the parting line (9).

4. The robotic arm according to claim 1, characterized in that, At least two of the segments (2) are also interconnected at one end by a rolling joint (19) such that the segments (2) can rotate relative to each other about a pivot axis (B); the circumferential edge (6) defines a bottom surface (7), which is V-shaped or parabolic when viewed in the direction of the pivot axis (B) and has two sides (8) extending obliquely with respect to the axis of rotation (A).

5. The robotic arm according to claim 4, characterized in that, The sides (8) of the circumferential edge (6) extend at an angle (α) between 10° and 30° with respect to the axis of rotation (A) at least in the region of the parting line (9).

6. The robotic arm according to claim 1, characterized in that, The second segment (2; 2b) also includes a transition portion (4) that extends from the joint portion (3) of the second segment (2; 2b) towards the joint portion (3) of the first segment (2; 2a), while crossing the parting line (9) existing between the two joint portions and then extending radially above the joint portion (3) of the first segment (2; 2a) at a preset distance. Wherein, the transition portion (4) of the second segment (2; 2b) has a circumferential edge (6), and the circumferential edge extends above the surface of the underlying joint portion (3) of the first segment (2; 2a) at a radial distance of less than 25 millimeters with respect to the rotation axis (A), and when viewed from a direction perpendicular to the rotation axis (A) and perpendicular to the longitudinal direction (L), the circumferential edge extends obliquely with respect to the rotation axis (A).

7. The robotic arm according to claim 6, characterized in that, The two segments (2) have adjacent edges (6; 17) that extend substantially parallel to each other at a preset position of the robotic arm within the region of a hinge joint (10).

8. The robotic arm according to claim 1, characterized in that, The transition portions (4) of the two segments (2) are formed such that the distance between adjacent transition portions (4) measured circumferentially with respect to the rotation axis (A) within the region of the circumferential edge (6) increases as the distance from the rotation axis (A) increases.

9. The robotic arm according to claim 8, characterized in that, The transition portions (4) of the two segments (2) are formed such that when the two segments (2) are bent to the maximum extent, a V-shaped gap remains between the transition portions within the region of adjacent circumferential edges (6).

10. The robotic arm according to claim 1, characterized in that, The parting line (9) existing between the joint portion (3) of the first segment (2; 2a) and the joint portion (3) of the second segment (2; 2b) is substantially centered between the two joint portions (3).

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