METHOD FOR MANUFACTURING A GRIPPING JAW BY MEANS OF 3D PRINTING

Description

[0001] The invention relates to a method for manufacturing a robot element, namely a gripper jaw,

[0002] Robotic gripping systems are facing increasingly demanding requirements and expanding application profiles. Conventional manufacturing methods, such as casting using appropriate molds, machining processes, etc., only partially cover these application areas. This means that not only do gripping systems on a robot have to be changed, increasing the robot's setup time, but several different gripping systems also have to be manufactured.

[0003] The present invention is therefore based on the objective of creating a method for manufacturing a robot element, namely a gripper jaw, which is multifunctional and reduces the setup time of a robot.

[0004] This problem is solved according to the invention by a method having the features of claim 1.

[0005] By manufacturing an entire gripper jaw using 3D printing, other manufacturing processes that would otherwise be necessary, such as attaching separate sensors and coating with (mostly flexible) materials, are eliminated.

[0006] According to the invention, such a gripper jaw is manufactured using multi-material printing, so that not only can special, mostly flexible outer surfaces or layers of a gripper element be flexibly designed, but also at least one sensor (capacitive, inductive, resistive, Hall effect) is integrated during the manufacture of the gripper jaw and printed along with it during the printing of the gripper jaw, i.e., it is itself manufactured by means of printing.

[0007] Furthermore, the manufacturing process according to the invention offers the possibility of ensuring the required load-bearing capacity, tensile strength, flexural strength, stiffness, hardness, etc., through appropriate material selection, particularly for the lower or inner layers of the gripping element, whereby different materials can be used to produce different layers. In this way, desired different material properties can be integrated into one and the same element or component in a single manufacturing process without the need for further processing steps.

[0008] In a preferred embodiment of the invention, a combination of several (identical or different) sensors is printed along with the gripper jaw during printing. This enables redundant and / or multifunctional sensor systems without requiring any post-processing of a component manufactured according to the invention.

[0009] In a further embodiment of the invention, connections, cables, plugs and / or connecting elements are printed along with the components, without requiring any post-processing of a component manufactured according to the invention.

[0010] In a particularly preferred embodiment of the invention, composite material, especially fiber reinforcement, is co-printed (microfiber) or embedded during printing (continuous fiber). For example, very short fiber segments, so-called microfibers (especially carbon fiber, polyamide, etc.), can already be contained within the printing material and thus applied (co-printed) to the print bed or to the existing layers using a nozzle. Alternatively, a fiber can also be inserted as a continuous fiber (especially carbon fiber) into any desired layer during printing or during a printing pause using a second nozzle.

[0011] In a further embodiment of the invention, sensors and fiber reinforcement are distributed across different layers during printing. This prevents conductive fiber reinforcement from interfering with sensors or even causing short circuits. Furthermore, an insulating layer can be provided at the interface between a layer or layers containing sensors and layers with electrically conductive fibers, thus preventing any (electrical) functional impairment of a sensor.

[0012] In a further embodiment of the invention, at least one camera is integrated by inserting / embedding it during printing (possibly also during a pause before printing the next layer).

[0013] In a particularly advantageous embodiment of the invention, an entire gripper jaw of a robot is printed in a single (printed) piece, possibly including joint elements, using 3D multi-material printing.

[0014] The aforementioned designs also advantageously reduce the weight compared to conventional gripping or actuation systems, since elements such as sensors, cables, plugs, connecting elements, etc., are printed and / or embedded. The fiber reinforcement according to the invention, achieved through 3D multi-material printing, also contributes to weight reduction by achieving higher load-bearing capacity, tensile strength, flexural strength, stiffness, hardness, etc., of the material through the aforementioned fiber reinforcement rather than by increasing the amount of material. Furthermore, the inventive method allows for the simple realization of bionic shapes, meaning that material is only used where it is necessary, for example, for reasons of strength.

[0015] Further advantageous embodiments of the inventions are specified in the dependent claims.

[0016] The invention is explained in more detail below with reference to the embodiments shown in the drawing.

[0017] The drawing shows: Fig. 1a a front view of a schematic representation of a gripping system of a robot manufactured according to the invention; Fig. 1b a side view of a gripping system according to Fig. 1a ; Fig. 1 a sectional view along the section line AA in Fig. 1b ; Fig. 1 your enlarged view of detail Z in Fig. 1a ; Fig. 2a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with capacitive sensors; Fig. 2-legged sectional view of the gripper finger along line AA in Fig. 2a ; Fig. 3a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with inductive sensors; Fig. 3-legged sectional view of the gripper finger along line AA in Fig. 3a ; Fig. 4a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with resistive sensors; Fig. 4 legged sectional view of the gripper finger along line AA in Fig. 4a ; Fig. 5a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with Hall sensors; Fig. 5 legged sectional view of the gripper finger along line AA in Fig. 5a ; Fig. 6a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with a combination of capacitive, inductive, and resistive sensors; Fig. 6: sectional view of the gripping finger along line AA in Fig. 6a ; Fig. 7a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with capacitive, inductive, resistive sensors and Hall sensors, each in different layers; Fig. 7b Sectional views of the gripper finger along lines AA, BB, CC and DD in Fig. 7a ; Fig. 8a a side view of the gripping fingers made of Fig. 1a bis Fig. 1d with multisensors; Fig. 8 leg sectional view of the gripper finger along line AA in Fig. 6a ;

[0018] The in Fig. 1a bis Fig. 1d The illustrated gripping system 1 of a robot consists of a control unit 3 and several gripping elements or actuators, for example two, designed as fingers 5. The control unit 3 forms the mechanical link between the fingers 5 and the robot and preferably also establishes an electrical connection between the two components. Each finger 5 is preferably equipped with its own actuator to allow for arbitrary rotation of the fingers 5 and their rapid assembly and disassembly. Additionally, the fingers can preferably be inclined – for example by 7° – in both directions relative to the longitudinal axis L to enable a reduction in the gripping distance or gripping time for different objects.

[0019] For gripping, the fingers 5, which are preferably rotationally symmetrical to the central axis M of the gripping system 1, can be positioned along an axis transverse to the central axis of the gripping system 1 (horizontally in the plane of the drawing). Fig. 1a ) between a maximum distance (as shown in the drawing) and a minimum distance (up to the point where the fingers touch each other).

[0020] Of course, the illustrated gripping system 1 with two fingers 5 is only an example of general gripping systems according to the invention, whereby gripping systems with several fingers, for example three fingers evenly distributed radially around the central axis M, are also conceivable.

[0021] The rotation, tilting and movement of the fingers 5 can be realized by a suitable device (in particular electric actuators) in the area of ​​the connection between the control unit 3 and the fingers 5 or in the fingers 5 themselves (for example in different finger sections or additional finger joints).

[0022] The two in Fig. 1a bis Fig. 1d The depicted fingers 5 have sensors 7 on their inner surfaces, which are integrated into one of the upper layers 23 or in the uppermost layer in the direction of the central axis M (by means of multi-material printing) and are preferably located below the outermost layer, which acts as the outer skin. In this way, the sensors 7 are protected against external mechanical contact. Suitable types of sensors include, for example, capacitive, resistive, inductive sensors, and Hall sensors.

[0023] The sensors 7 have leads 7a, which are printed within the fingers 5 along with the sensors 7 and lead to the control system or the electronics housed therein. The sensors 7 can be accessed from the outside via their leads 7a, possibly using appropriate connectors (plugs, sockets, etc.) and connected to corresponding ports on a robot. These connectors can also be printed or embedded.

[0024] The sensor 7, in its various forms (capacitor, coil, resistor, strain gauge, Hall sensor, etc.), is preferably located coplanarly within a layer (for example, the upper outer layer) which itself is designed as an electrically insulating layer.

[0025] Below or above this layer with a sensor 7, fiber reinforcements (through microfiber in the printing material or the introduction of continuous fibers into the printing bed) may also be present, even if these consist of an electrically conductive material (e.g. carbon).

[0026] A camera 19 is embedded in the control unit 3 in the middle area between the fingers 5, the lens 21 of which is directed towards the fingers 5 or towards an object to be grasped with them and covers the area between the fingers 5 in order to capture an image of an object to be grasped or operated.

[0027] The camera 19 can be embedded during a printing break by placing it in a printed recess or by printing around a positioned camera so that its lens or objective is located in a desired position with the desired focus.

[0028] Advantageously, the connecting cables (terminals) and connectors for attaching the camera are printed or embedded along with the housing, so that the camera does not need to be connected externally or via external surfaces. This integrated design helps to reduce the overall height and avoids unwanted external cable routing.

[0029] In Fig. 2 bis Fig. 8 Different versions of the in Fig. 1 or in the Figuren 1a bis 1d The sensor 7, as generally depicted, is explained.

[0030] Thus, the in Fig. 2a and Fig. 2b In a first embodiment, capacitive sensors 9 with connecting leads 9a are mounted on the fingers 5, which are shown in detail, at their end regions or gripping surfaces of the fingertips. As shown in the figure below. Fig. 2a As can be seen, the two plates of sensor 9 lie horizontally next to each other in the plane of the drawing, although an arrangement one above the other (vertically in the plane of the drawing) is of course also conceivable. The two plates of the capacitive sensor (capacitor) realized in this way lie coplanarly in the same (outer) layer, which also serves as insulation (dielectric) between the plates.

[0031] In the Fig. 3a and Fig. 3b In the second embodiment shown, the fingers 5 have coils 11 located within a layer (coplanar to the layer plane) as inductive sensors (instead of capacitive sensors 9) with leads 11a (end tap) and 11b (center tap). The layer shown in the top view is any layer that can be inductively influenced. Preferably, it is one of the upper layers or even the outermost layer of the finger, in order to increase the sensitivity of the sensor.

[0032] The in Fig. 4a and Fig. 4b The third embodiment shown illustrates how, in an analogous manner, Fig. 3a and Fig. 3b Instead of coils 11, strain gauges 13 (resistive sensor) were printed coplanarly with leads 13a in one plane, whereby the layer shown can be any layer which in this case is mechanically influenced, and does not necessarily have to be the outermost layer. The strain gauge 13 preferably has a greater extent (length) in the direction of the longitudinal axis L of the finger 5 than its width transverse to the longitudinal axis L, so that changes in length due to bending of the finger 5 under load can be detected more easily.

[0033] The in Fig. 5a and Fig. 5b The fourth embodiment shown illustrates how – in an analogous manner to Fig. 4a and Fig. 4b Instead of strain gauges 13 - Hall sensors 15 were printed coplanarly with leads 15a, b, c in one plane, whereby the layer shown can be any layer which in this case is magnetically (inductively) influenced, and does not necessarily have to be the outermost layer.

[0034] From the in Fig. 6a and Fig. 6b As shown in the fifth embodiment, it can be seen that a combination of several sensors, namely for example a capacitive sensor 9, an inductive sensor 11 and a resistive sensor 13, can also be printed within one layer.

[0035] Instead of printing several identical or different sensors 9, 11, 13, 15 and any combination thereof within a single layer, it is, as in the Fig. 7a and Fig. 7b As shown in the sixth embodiment, it is also possible to distribute sensors 9, 11, 13, 15 across different layers. Instead of as in Fig. 7b As shown in the right-hand figure (section AA), the two plates of a capacitive sensor 9, which lie horizontally next to each other in the plane of the drawing, can of course also be arranged vertically above one another or offset from each other. The circular, schematic design of the coil 11 shown in section BB is only an example of any spiral, and in particular angular, design.

[0036] The layer-by-layer construction using multi-material printing (3D) also makes it possible to combine different substrate materials. For example, harder substrate materials can be used in layers furthest from gripping surfaces (perpendicular to the finger's longitudinal axis L) to increase the stability of a gripping element, especially finger 5. Conversely, soft, elastic materials, such as rubber, can be used in the area of ​​gripping surfaces 17, particularly in the end regions (fingertips), for printing an outer layer (and possibly also the layers below) to increase friction between finger 5 and the object and reduce damage to the object being gripped.

[0037] The in Fig. 8a and Fig. 8bThe sixth embodiment shown depicts a multisensor, in particular a 4-in-1 sensor, with two rectangular spirals 25 (first multisensor element) and 26 (second multisensor element) arranged one above the other in the plane of the drawing. Depending on how the spirals 25 and 26 are connected or interconnected via their terminals 25a, b and 26a, b, this multisensor can be operated as an inductive, capacitive, or resistive sensor (strain gauge).

[0038] If the two end taps 25a and 26a (or 25b and 26b) are used, the multisensor acts as a capacitive sensor, with the two sensor elements 25 and 26 serving as capacitor plates.

[0039] If only the outer and inner connections or taps 25a and 25b or 26a and 26b are used, each sensor element 25 and 26 acts as a resistive or inductive sensor. Instead of using two of these sensors, it is of course also possible to connect the sensor elements in series, so that they act as one larger inductive or resistive sensor.

[0040] If the sensor elements 25 and 26 act as two sensors, the two obtained measured values ​​can be used for cross-checking (simple redundancy) or for eliminating interfering factors (for example, eliminating the influence of heating on a measurement result). Reference symbol list:

[0041] 1 Gripping system 3 Control unit 5 Finger 7 Sensor 7a Sensor lead 7 9 Capacitor plates or capacitive sensor 9a Sensor lead 9 11 Coils or inductive sensor 11a Sensor lead 11 Outer connection (end tap) 11b Sensor lead 11 Inner connection (center tap) 13 Strain gauges or resistive sensor 13a Sensor lead 15 Hall sensors 15a Sensor lead 17 Gripping surface 19 Camera 21 Lens 23 Fiber reinforcement 25 First multisensor element 25a Sensor lead outer connection (end tap) 25 25b Sensor lead inner connection (inner tap) 25 26 Second multisensor element 26a Sensor lead outer connection (end tap) 26 26b Lead Inner connection (inner tap) of the sensor 26 M Central axis of the gripping system 1 L Longitudinal axis of the finger 5 Z Detail

Claims

1. Method for 3D printing a robot element, namely a gripping jaw, in particular a finger (5), for use in robotics, wherein, by means of multi-material printing, at least one sensor (7) is co-printed during the printing of the gripping jaw.

2. Method according to claim 1, characterized in that a combination of a plurality of sensors (9, 11, 13, 15) is co-printed during the printing of the gripping jaw.

3. Method according to claim 1 or claim 2, characterized in that connections, lines (7a, 9a, 11a, b, 13a, 15a, 25a, b, 26a, b), plugs and / or connecting elements are co-printed.

4. Method according to any of the preceding claims, characterized in that composite material, in particular fiber reinforcement, is co-printed or embedded.

5. Method according to any of the preceding claims, characterized in that the sensors (9, 11, 13, 15) and the fiber reinforcement are distributed across different planes during printing.

6. Method according to any of the preceding claims, characterized in that at least one camera (19) is integrated in the gripping jaw by means of embedding during printing.

7. Method according to any of the preceding claims, characterized in that an entire finger (5) is printed in a single piece.

8. Gripping jaw, in particular a finger (5), for a robot, which gripping jaw is manufactured by means of a method according to any of the preceding claims.