Cable-driven robots

Abstract

The present invention relates to a cable-driven robot (100) comprising: a base structure (1); a plurality of cables (C); a movable element (EM) suspended by the plurality of cables (C); a movement system (2) for moving the cables (C) and thus for moving the movable element (EM) relative to the base structure (1), the movable element (EM) comprising a plurality of movement units (20) of the cables. At least one movement unit (20) comprises: a frame (21) hinged about a hinge axis (V) to a component (11) of the base structure (1); a motor (3) mounted on the frame (21) and including a rotation axis (31); at least one winding / unwinding element (4) of the cables (C). The winding / unwinding element (4) comprises a drum (40) mounted on the frame (21) and rotatably driven by the rotation axis of the motor (3). The drum (40) includes a side surface (41) shaped to include a helical groove (42) extending coaxially with respect to the axis of the drum (40) and defining a series of hollow turns, each hollow turn being adapted to receive and accommodate a corresponding winding turn of the cable (C) within itself during the winding / unwinding of the cable (C) around the drum (40).

Description

Technical Field

[0001] This invention relates to the technical field of parallel robots, particularly cable-driven robots. Background Technology

[0002] Cable-driven robots use cables to keep components or devices suspended and to move them within three-dimensional space.

[0003] Figure 1A This schematically illustrates the classic structure of a cable-driven robot.

[0004] Cable-driven robots consist of: a fixed base structure (F) or frame; and movable elements (EM) that are suspended by a series of cables (C) and must move in three-dimensional space relative to the fixed base structure (F) by moving the cables as they are extended or shortened.

[0005] The movable element (E) may include, for example, a tool or platform, on which an operating mechanism is mounted, the operating mechanism being pre-configured to perform a defined operation, such as picking up and releasing an object, or other types of operation or process.

[0006] In this regard, cable-driven robots include systems for moving cables, i.e., systems for extending and shortening cables.

[0007] The cable moving system (S) includes multiple moving units (G) (e.g., six moving units as shown in Figure (1A)), which are mounted on the infrastructure (F) and are responsible for moving the cable, thereby responsible for moving the movable element (E).

[0008] In existing cable-driven robots, each moving unit (G) (e.g., see...) Figure 1B , 1C (And 1D, which illustrates various embodiments of the mobile unit used in the prior art) includes an electric motor (M), which is rigidly fixed and constrained to a base structure (F) and is provided with a rotating shaft and a drum (T), which is guided directly or by a mechanism to the rotating shaft of the electric motor (M) and can be driven by the rotation of the electric motor (M), with associated cables wound / unwound on the electric motor (M).

[0009] Therefore, each cable (C) includes a first end fixed to the movable element (E) and a second end fixed to the corresponding drum (T) of the movable unit (G).

[0010] The motor (M) of each moving unit (G) is pre-set to actuate the drum (T) to rotate in two opposite directions of rotation, which determines whether the cable on the drum is wound or unwound, and thus determines whether it is shortened or lengthened.

[0011] In this way, each cable connected to the movable operating element can be shortened (pulled) or extended (released), so its length (extension) between the fixed point of the movable element and the associated drum can be varied by decreasing or increasing.

[0012] Therefore, by appropriately actuating various electric motors, that is, by rotating and actuating the opposing drums, thereby lengthening or shortening various cables, movable elements can be moved and displaced relative to the base structure, and their position in the three-dimensional workspace can be changed.

[0013] In existing cable-driven robots, the drum (T) where the cable is wound / unwound typically includes a smooth cylindrical side surface.

[0014] As mentioned above, Figure 1B , 1C Figure 1D shows an example of a cable-driven moving unit (G) present in a prior art cable-driven robot.

[0015] These diagrams show an electric motor (M) and a drum (T) fixed to a base structure (F). After the drum (T) is rotated in one or the other direction, a cable (C) is wound / unwound on the drum.

[0016] As can be clearly seen in these figures, each cable (C) includes a winding portion (CP) on a drum (T), which is formed by a series of turns wound on the drum (T) having the same diameter and adjacent to each other.

[0017] Therefore, the winding portion (CP) forms a spiral winding around the drum, wherein the winding turns are adjacent to each other and in contact with each other.

[0018] For each moving unit (G), the moving system (S) also includes a cable guide element (R) or return element (R) for the cable (C), such as an eyelet or pulley or the like, which is pre-configured to guide, switch and orient the cable (C) relative to the drum (T) according to the actual position of the movable element (E) in space.

[0019] The prior art cable-driven robots described above are, for example, described in document FR2910833.

[0020] However, this type of cable-driven robot has some drawbacks.

[0021] First, when the cable is wound in a spiral manner on a drum with a winding section, the winding section includes a series of turns that are adjacent to and in contact with each other. During the unwinding / winding process of the cable, the turns may drag each other, thereby increasing the wear of the cable.

[0022] Furthermore, during the movement of the movable element relative to the drum in space, since the drum is fixed, the cable is subjected to insignificant torque and / or bending stress when the cable is switched by the guide element or return element because it is fixed to the rigid connection and to the motor of the fixed base structure. Summary of the Invention

[0023] Therefore, the object of the present invention is to describe a novel cable-driven robot that can eliminate the aforementioned disadvantages of the prior art.

[0024] In particular, the purpose of this invention is to describe a novel cable-driven robot that can maintain the integrity of the cable, or at least significantly reduce wear, while ensuring good movement of movable elements in three-dimensional space.

[0025] Therefore, another object of the present invention is to describe a novel cable-driven robot that can move a cable in a rapid and precise manner as a function of the position to which a movable manipulator will be brought in and positioned, without generating sudden stress on the cable in the event of a sharp rotation of the cable relative to the base structure.

[0026] The cable-driven robot according to the claims achieves the above objectives. Attached Figure Description

[0027] The features of preferred, but not exclusive, embodiments of the cable-driven robot of the present invention will be set forth in the following description with reference to the accompanying tables, wherein:

[0028] -As mentioned above Figure 1A The example illustrates a cable-driven robot of the prior art, as mentioned earlier. Figure 1B , 1C Figure 1D illustrates an example of an embodiment of a cable-driven unit present in a prior art cable-driven robot;

[0029] - Figure 2 A schematic perspective view illustrates the cable-driven robot object of the present invention;

[0030] - Figure 3A According to a preferred embodiment, some key components of the cable-driven robot object of the present invention are schematically shown in a plan view;

[0031] - Figure 3B Shown in the form of a first side view Figure 3A Components;

[0032] - Figure 3C A second side view, opposite to the first side view, is shown. Figure 3A Components;

[0033] - Figure 4A According to another possible preferred embodiment, some key components of the cable-driven robot object of the present invention are schematically shown in a plan view;

[0034] - Figure 4B It shows Figure 4A First side view of the component;

[0035] - Figure 4C A second side view, opposite to the first side view, is shown. Figure 4A Components. Detailed Implementation

[0036] Refer to the accompanying tables, especially Figure 2 and Figures 3A-3C 4A-4C, and reference numeral (100) indicate the overall cable-driven robot of the present invention.

[0037] The cable-driven robot (100) includes a basic structure (1), multiple cables (C) and a movable element (EM) which is suspended by the multiple cables.

[0038] In this respect, each of the multiple cables (C) includes a first end fixed to the movable operating element (EM) (see...). Figure 2 ).

[0039] The cable-driven robot (100) also includes a mobility system (2) for moving the cable (C) and thus for moving movable operating elements (EM) in space relative to the infrastructure (1).

[0040] The mobile system (2) includes multiple mobile units (20) of a cable (C).

[0041] The cable-driven robot (100) described in this invention is characterized in that at least one of the plurality of moving units (20) is implemented in the following manner.

[0042] At least one movable unit (20), and preferably all of the multiple movable units (20), includes a frame (21) pivotally hinged about a vertical hinge axis (V) to a component (11) of the base structure (1), such that the frame (21) is rotatable relative to the base structure (1) about the vertical hinge axis (V).

[0043] The moving unit (20) also includes (for example, see...) Figure 3B and 3C ):

[0044] The electric motor (3) is directly mounted on the frame (21) and includes a rotating shaft (31);

[0045] At least one winding / unwinding element (4) of the cable (C) has a fixing point at which the second end of one of the plurality of cables (C) is fixed. The winding / unwinding element (4) includes a drum (40) which is directly mounted on the frame (21) in a manner connected to the rotating shaft (31) of the motor (3) and can be driven to rotate after actuating the rotating shaft (31) of the motor (3) in one rotational direction or another rotational direction.

[0046] More in detail (e.g.) Figure 3A As shown), the drum (40) includes a side surface (41) shaped to include a helical groove (42) extending coaxially with respect to the axis of the drum (40) and defining a series of hollow turns. During the winding / unwinding of the cable (C) around the drum (40), each hollow turn is adapted to receive and accommodate a corresponding winding turn of the cable (C) within it.

[0047] Specifically, the spiral groove (42) is implemented to have depth and width such that each of the series of hollow turns defined therefrom can accommodate and receive only one corresponding winding turn of the hollow (C) inside it.

[0048] In this way, each turn of cable wound around the drum will remain separate and distinct from the previous and subsequent spiral sections.

[0049] In essence, in other words, each turn of the spiral groove will have a bottom wall and two side walls (or supports), between which only one cable (C) and the corresponding winding turn (C) will be accommodated.

[0050] Therefore, due to the specific construction of the drum around which the cable is wound or unwound during the movement of the movable operating element, each turn of the cable around the drum will remain separate and distinct from the previous and subsequent turns, thus preventing any mutual drag between them, which could jeopardize its integrity and be a cause of rapid wear.

[0051] Furthermore, since the motor that actuates the rotation of the drum and the drum itself around which the cable is wound / unwound are both mounted on a frame that pivots relative to the base structure, i.e., can rotate about a vertical hinge axis relative to a portion of the base structure, the cable does not deflect or twist during the movement of the movable element in space.

[0052] This is because, as the drum rotates with the frame relative to the base structure, the drum will automatically adjust its orientation and position to the position that the movable element will occupy time and time again, so that in practice, the drum and the actual position occupied by the movable element are automatically aligned.

[0053] In essence, the portion of the cable between the movable element and the drum, that is, the portion between the anchor point of the movable element and the winding portion wound on the drum, will always be substantially perpendicular to the axis of rotation of the drum.

[0054] This method prevents stress from being generated when the cable is bent or twisted, which can cause cable wear and deterioration over time.

[0055] In addition, to further reduce the initiation of cable wear, the side surface of the drum on which the spiral grooves are formed can be made of a special material with a low coefficient of friction.

[0056] Other advantageous features of the cable-driven robot of the present invention are described below.

[0057] The motor (3) is preferably mounted on the frame (21) such that the axis (A) of the rotation shaft (31) is perpendicular to the vertical hinge axis (V) of the frame (21) at the component (11) of the base structure (1), and the axis (A) of the rotation shaft (31) is aligned with the vertical hinge axis (V) of the frame (21), and is located on a plane perpendicular to the component (11) of the base structure (1) that is hinged to the frame (21).

[0058] This contributes to the sensitivity and responsiveness of the frame, and thus to the sensitivity and responsiveness of the motor mounted on it, so as to autonomously and automatically align with the position that the movable element will occupy from time to time.

[0059] For this purpose, the drum (40) is further mounted on the frame (21) so that it can be rotated about a horizontal axis of rotation (O) located in a vertical plane parallel to the vertical hinge axis (V) of the frame (1) and parallel to the axis (A) of the rotation axis (31).

[0060] Another preferred and advantageous aspect involves the fact that the drum (40) is mounted on the frame (21), and the helical groove (42) is realized on the side surface of the drum (40) such that the transverse intermediate plane (PT1) passing through the drum (40) is also the intermediate plane with respect to the helical groove (42), and defines a vertical plane that is aligned at the component (11) of the base structure (1) and contains the vertical hinge axis (V) of the frame (21), which is perpendicular to the axis of rotation (31) of the motor (3) (see details). Figure 3A ).

[0061] In this way, as the cable is wound or unwound from the drum, the coiled turns of the cable will rest on only one of the two walls (or supports) of the spiral groove. In other words, during the winding process, a single turn of the cable will be able to rest on the first wall (or support) of the opposite turn of the cable coil, and during the unwinding process of the cable from the drum, the turn will unwind instead of resting on the second wall (or adjacent part) of the opposite turn of the spiral groove.

[0062] This will further reduce the risk and likelihood of cable wear and tear.

[0063] according to Figures 3A to 3C In the preferred but non-exclusive embodiment shown, the drum (40) is connected to the rotating shaft (31) of the electric motor (3) via a drive transmission system (7) comprising: a gear (71) mounted on and connected to the frame (21) and rotatably driven by the rotating shaft (31) of the electric motor (3); a sub-shaft (72) supported by the gear (71) and including a toothed portion (720); and a toothed belt (73) wound around the toothed portion (720) of the sub-shaft (72) and wound around a crown wheel (74) mounted at the end of the drum (40).

[0064] According to such Figures 4A to 4C In another possible preferred embodiment shown, the at least one moving unit (20) may further include a second drum (5) mounted on the frame (21) to be connected to the rotating shaft (31) of the motor (3) and can be rotated after rotating the rotating shaft (31) of the motor (3) in one or the other direction.

[0065] The second drum (5) includes a second fixing point for fixing one end of a second cable (C) among a plurality of cables (C), and includes a side surface (51) shaped to include a second helical groove (52) extending coaxially with respect to the axis of the second drum (5) and defining a series of hollow turns, each hollow turn being adapted to receive and accommodate a corresponding wound turn of the second cable (C) within it during the winding / unwinding of the second cable (C) around the second drum (5).

[0066] In this way, and advantageously, using a single motor, two cables can be commanded to move.

[0067] In order for the second cable to achieve the same effects and advantages as the embodiment with a single drum, the second drum (5) will be mounted on the frame (21) in the following manner (e.g. Figure 4A (As shown).

[0068] The second drum (5) is mounted on the frame (21) such that at the component (11) of the base structure (1), the relative axis of rotation (O2) is horizontal and parallel to the axis of rotation (O) of the drum (40) and parallel to the vertical hinge axis (V) of the frame (21).

[0069] More specifically, the second drum (5) is mounted on the frame (21) such that the transverse intermediate plane (PT2) passing through the second drum (5) is also the intermediate plane about the second spiral groove (52) and defines a vertical plane that is aligned at the component (11) of the base structure (1) and includes the vertical hinge axis (V) of the frame (21) that is perpendicular to the axis of rotation (31) of the motor (3) and coincides with the transverse intermediate plane (PT1) of the drum (40).

[0070] In order to actuate the rotation of the second drum (5), while rotating the actuating drum (40), a second crown wheel (75) and a second toothed belt (76) are included. The second crown wheel (75) is mounted on the end of the second drum, and the second toothed belt (76) is wound around the second crown drum (75) and on the gear hub (77) mounted on the countershaft (72) of the drive transmission system (7).

Claims

1. A cable-driven robot (100), comprising: Basic structure (1); Multiple cables (C); A movable operating element (EM) is suspended by the plurality of cables (C), each of the plurality of cables (C) including a first end fixed to the movable operating element (EM); A moving system (2) for moving the cable (C) and thus for moving the movable operating element (EM) in space relative to the infrastructure (1), the moving system (2) comprising a plurality of moving units (20) of the cable. At least one of the plurality of moving units (20) includes: The frame (21) is pivotally hinged to a component (11) of the base structure (1) about a vertical hinge axis (V), such that the frame (21) can rotate relative to the base structure (1) about the vertical hinge axis (V); An electric motor (3) is mounted on the frame (21) and includes a rotating shaft (31). At least one winding / unwinding element (4) of a cable (C) has a fixing point at which the second end of one of the plurality of cables (C) is fixed. The winding / unwinding element (4) includes a drum (40) mounted on the frame (21) in a manner connected to the rotating shaft (31) of the motor (3) and capable of being driven to rotate after actuating the rotating shaft (31) of the motor (3) in one or another rotational direction. The drum (40) includes a side surface (41) conforming to include a helical groove (42) extending coaxially with respect to the axis of the drum (40) and defining a series of hollow turns. During the winding / unwinding of the cable (C) around the drum (40), each hollow turn is adapted to receive and accommodate a corresponding winding turn of the cable (C) within its interior. The drum (40) is connected to the rotating shaft (31) of the motor (3) via a drive transmission system (7). The drive transmission system (7) includes: a gear (71) mounted on the frame (21) and connected to it, and can be rotated and driven by the rotating shaft (31) of the motor (3); a secondary shaft (72) supported by the gear (71) and including a toothed portion (720); and a toothed belt (73) wound around the toothed portion (720) of the secondary shaft (72) and wound around a crown wheel (74) mounted at the end of the drum (40).

2. The cable-driven robot (100) according to claim 1, wherein the motor (3) is mounted on the frame (21) such that the axis (A) of the rotation shaft (31) is perpendicular to the vertical hinge axis (V) of the frame (21) at the component (11) of the base structure (1), and such that the axis (A) of the rotation shaft (31) is aligned with the vertical hinge axis (V) of the frame (21) and is located on a plane perpendicular to the component (11) of the base structure (1) hinged to the frame (21).

3. The cable-driven robot (100) according to any one of claims 1 and 2, wherein the drum (40) is mounted on the frame (21) such that it can be rotated about a horizontal axis of rotation (O), the horizontal axis of rotation being located in a vertical plane parallel to the vertical hinge axis (V) of the frame (21) and parallel to the axis (A) of the rotation axis (31).

4. The cable-driven robot (100) according to claim 3, wherein the drum (40) is mounted on the frame (21), and wherein the helical groove (42) is implemented on the side surface of the drum (40) in such a way that the transverse intermediate plane (PT1) passing through the drum (40) is also the intermediate plane about the helical groove (42) and defines a vertical plane that is aligned at a component (11) of the base structure (1) and includes the vertical hinge axis (V) of the frame (21) perpendicular to the axis of the rotation axis (31) of the motor (3).

5. The cable-driven robot (100) according to any one of claims 1-2 and 4, wherein the at least one moving unit (20) includes a second drum (5) mounted on the frame (21) for connection to the rotating shaft (31) of the motor (3) and rotatably driven after rotatably actuating the rotating shaft (31) of the motor (3) in one or the other direction, the second drum (5) having a second fixing point for fixing one end of a second cable (C) among the plurality of cables (C) and including a side surface (51) conforming to include a second helical groove (52) extending coaxially relative to the axis of the second drum (5) and defining a series of hollow turns, each hollow turn being adapted to receive and accommodate a corresponding wound turn of the second cable (C) within itself during the winding / unwinding of the second cable (C) around the second drum (5).

6. The cable-driven robot (100) according to claim 3, wherein the at least one moving unit (20) includes a second drum (5) mounted on the frame (21) for connection to the rotation shaft (31) of the motor (3) and rotatably driven after rotatably actuating the rotation shaft (31) of the motor (3) in one or the other direction, the second drum (5) having a second fixing point for fixing one end of a second cable (C) among the plurality of cables (C) and including a side surface (51) conforming to include a second helical groove (52) extending coaxially relative to the axis of the second drum (5) and defining a series of hollow turns, each hollow turn being adapted to receive and accommodate a corresponding wound turn of the second cable (C) within itself during the winding / unwinding of the second cable (C) around the second drum (5).

7. The cable-driven robot (100) according to claim 5, wherein the second drum (5) is mounted on the frame (21) such that at the component (11) of the base structure (1), the relative axis of rotation (O2) is horizontal and parallel to the axis of rotation (O) of the drum (40) and parallel to the vertical hinge axis (V) of the frame (21).

8. The cable-driven robot (100) according to claim 6, wherein the second drum (5) is mounted on the frame (21) such that at the component (11) of the base structure (1), the relative axis of rotation (O2) is horizontal and parallel to the axis of rotation (O) of the drum (40) and parallel to the vertical hinge axis (V) of the frame (21).

9. The cable-driven robot (100) according to any one of claims 7-8, wherein the second drum (5) is mounted on the frame (21) such that the transverse intermediate plane (PT2) passing through the second drum (5) is also the intermediate plane about the second helical groove (52) and defines a vertical plane that is aligned at a component (11) of the base structure (1) and includes the vertical hinge axis (V) of the frame (21), the component being perpendicular to the axis of the rotation axis (31) of the motor (3) and coinciding with the transverse intermediate plane (PT1) of the drum (40).

10. The cable-driven robot (100) according to claim 5, comprising a second crown wheel (75) mounted on the end of the second drum (5) and a second toothed belt (76) wound on the second crown wheel (75) and mounted on the geared hub (77) on the countershaft (72) of the drive transmission system (7).

11. The cable-driven robot (100) according to any one of claims 6-8, comprising a second crown wheel (75) mounted on the end of the second drum (5) and a second toothed belt (76) wound on the second crown wheel (75) and mounted on the geared hub (77) on the countershaft (72) of the drive transmission system (7).

12. The cable-driven robot (100) according to claim 9, comprising a second crown wheel (75) mounted on the end of the second drum (5) and a second toothed belt (76) wound on the second crown wheel (75) and mounted on the geared hub (77) on the countershaft (72) of the drive transmission system (7).

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