Device for holding a robot arm in at least one predetermined position in aerospace applications, robot arm and spacecraft

Abstract

Device for holding a robot arm (600) in at least one predetermined position for spaceflight applications, wherein the robot arm (600) comprises several robot segments (610, 612, 614, 616, 618) connected to one another by means of robot joints (602, 604, 606, 608) and the device (200) has a positive locking releasable locking device, robot arm (600) for spaceflight applications, wherein the robot arm (600) comprises several robot segments (610, 612, 614, 616, 618) connected to one another by means of robot joints (602, 604, 606, 608) and such a device (200), and spacecraft with at least one such robot arm (600).

Description

The invention relates to a device for holding a robot arm in at least one predetermined position during space application. The invention also relates to a robot arm for space transportation use. The invention also relates to a spacecraft.When using robot arms on the ground, it is always possible to rely on brakes to fix the robot arm if necessary for safety reasons or other requirements. These brakes generally consist of brake pads and a brake disc, the friction of which enables the locking or braking. In space applications with robotic arms, additional aspects must be considered. On the one hand, it is absolutely necessary to prevent brake dust from being produced. On the other hand, it must be ensured that the brake can be both released and activated under all circumstances, which is not possible as easily with conventional brake mechanisms, however. Nevertheless, in space it is essential to brake or fix a robot arm in order to prevent undesired movements. This may be necessary, for example, if a satellite in space is gripped by the robot arm and the system of service satellite and the gripped target satellite is to be brought safely to glow in the earth's atmosphere.Additional, specific challenges are present in space: the extreme environment of space with vacuum, zero gravity, extreme temperature fluctuations and ionizing radiation requires special design measures. Conventional pneumatic or hydraulic drive systems are problematic due to leakage risks and the risk of freezing working media. In addition, an absolute freedom from contamination is required, since even very small particles can damage sensitive sensors or optical systems. Freedom from maintenance is essential since repairs in space are not possible. At the same time, the highest reliability requirements must be met, since a failure of the detection device can lead to the loss of the entire mission.Known solutions from the prior art, as developed for example for direct drive industrial robots, typically use pneumatic or hydraulic cylinders with complex pick-up and lock-up systems, which have active drive units. In this context, reference is made to the document DE 10 2018 110 079 A1, which relates to a safety device for a manipulator, such as industrial robots, in particular with direct drive. The securing device has at least one receiving unit, at least one blocking unit and at least one drive unit. The receiving unit is fixed in a rotationally fixed manner on a first manipulator arm of the manipulator. The blocking unit is fixed in a rotationally fixed manner on a second manipulator arm of the manipulator, which can be moved by means of a manipulator drive, in particular a direct drive, relative to the first manipulator arm via a joint about a rotational and / or pivot axis. The locking unit can be transferred by the drive unit from a release position into a locking position. In the release position, the first manipulator arm and the second manipulator arm are released for movement, in particular rotation, relative to one another. In the locked position, the locking unit engages in the receiving unit transversely to the direction of movement, in particular the direction of rotation about the rotational and / or pivot axis, forming a rear grip and fixes the first manipulator arm and the second manipulator arm relative to one another so as to prevent movement, in particular about the rotational and / or pivot axis. However, such systems are unsuitable for aerospace applications because they are prone to leakage, require working media that can outgas or freeze in vacuum, and because of their complexity are maintenance intensive.The object of the invention is to improve a device mentioned at the beginning structurally and / or functionally. In addition, the object of the invention is to improve a robot arm mentioned at the beginning in a structural and / or functional manner. In addition, the object of the invention is to improve a spacecraft mentioned at the beginning in a structural and / or functional manner.The object is achieved with a device having the features of claim 1. In addition, the object is achieved with a robot arm having the features of claim 7. In addition, the object is achieved with a spacecraft having the features of claim 8.The device according to the invention is designed and / or arrangeable for holding a robot arm in at least one predefined position when used in space. The robot arm has a plurality of robot links. The robot links are connected to each other by means of robot joints. The device has a positively acting releasable fixing device.In contrast to known pneumatic or hydraulic drive systems, the locking device of the device according to the invention can operate completely mechanically and is therefore capable of vacuum, maintenance-free and absolutely free of contamination. The locking device can be operated both in a normally blocked configuration (fail-safe) and in a normally released configuration, depending on the mission requirement.The fixing device can have at least one perforated disk. The locking device can have at least one locking bolt. The at least one locking bolt can be displaceable between a release position and a locking position. The positive effect of the locking device can be realized by the engagement of the at least one locking bolt in corresponding receptacles or recesses. The locking bolt can be arranged transversely to a direction of movement of a robot member to be fixed. This arrangement ensures reliable transmission of force without wear due to friction and prevents the formation of particles. The fixing device can have a perforated disk and at least one locking bolt for each robot joint. The at least one locking bolt can be displaceable in the direction of extension of its longitudinal axis. The bidirectional drive of the locking bolt enables both the fixing and the release of the connection by appropriate actuation in both directions. The at least one locking bolt can be passively displaceable under the action of a prestressing force and / or actively displaceable with the aid of an actuator device.The at least one perforated disk can have at least one hole. The at least one perforated disk can have a plurality of holes. The holes may be arranged distributed in the circumferential direction. The holes may be arranged evenly distributed in the circumferential direction. The at least one locking bolt may correspond to the at least one hole. The at least one locking pin may be configured and / or arranged to engage the at least one hole to retain the robotic arm.The at least one locking bolt can have a conical end assigned to the at least one perforated disk. The at least one locking bolt can have a ball-segment-shaped end assigned to the at least one perforated disk.The securement device can have at least one mechanical energy store. The at least one mechanical energy store can be designed and / or arranged to act on the at least one locking bolt. The at least one mechanical energy store can be designed and / or arranged to act on the at least one locking bolt in the direction of the locking position. The at least one mechanical energy store can be designed and / or arranged to act on the at least one locking bolt in the direction of the release position. The at least one mechanical energy store can have at least one spring. The at least one spring can be designed as a compression spring and / or as a helical spring. The mechanical energy store may be configured and / or arranged to store energy over long periods of time without the need for working media.The device may comprise at least one retaining-release device. The restraint release device can also be referred to as a hold down and release mechanism (HDRM). The retaining-releasing device can be designed and / or arranged to hold and / or release the at least one locking bolt. The retaining-releasing device can be designed and / or arranged to hold the at least one locking bolt in the release position and / or to release a displacement into the locking position. The retaining-releasing device can be designed and / or arranged to hold the at least one locking bolt in the locking position and / or to release a displacement into the releasing position. The restraint release device can meet the stringent requirements of space technology and be designed according to established space standards (such as ECSS-E-ST-33-01C). The restraint release device can be designed specifically for use in spacecraft and is distinguished by its reliability, redundancy and low-shock triggering. Unlike industrial latch means or securing devices, the restraint release device will be qualified for the extreme conditions of space and will function without maintenance for years. The restraint release device can operate without pyrotechnics and can be implemented, for example, by means of shape memory alloy (SMA) elements, paraffin actuators or other proven space travel technologies. This ensures a controlled, reproducible release without the disadvantages of explosive bodies or other elements which can be used once.The locking device can be designed redundantly, wherein a plurality of independent locking bolts and / or a plurality of independent mechanical energy stores can be provided. This ensures the functionality of the system even in the event of failure of individual components. The redundancy can be implemented both as active redundancy, in which all systems operate simultaneously, and as passive redundancy, in which backup systems are activated if necessary.All components of the locking device can be made of materials which are space-qualified. Such materials may be designed and / or suitable to withstand the extreme temperature ranges from -150° C. to +120° C. and / or be resistant to ionizing radiation. The materials used may have minimal outgassing properties and may meet space-specific requirements, for example the NASA outgassing database (ASTM E595).The fixing device can be designed thermally in such a way that it functions reliably even in the event of extreme temperature fluctuations. The at least one mechanical energy store can be dimensioned in such a way that it retains its spring force even at low temperatures. If necessary, a heating device and / or thermal insulation can be provided.All movable parts can be designed such that no particle generation takes place. All surfaces may be provided with a spatially suitable coating in order to prevent particle release. The locking device can operate completely free of lubricant in order to avoid outgassing in a vacuum.The robot arm is designed and / or arrangeable for space travel application. The robot arm may be configured and / or arrangeable to grasp and / or hold space objects. The robot arm has a plurality of robot links. The robot links are connected to each other by means of robot joints. Two robot links can be connected to one another by means of a robot joint. The robot arm has the device according to the invention.The spacecraft has at least one such robot arm. The spacecraft may be a spacecraft, a space station, a space probe, an artificial satellite, for example a service satellite, or a rover. The device may be configured and / or arranged to fix a robot arm during critical maneuvers such as path changes, to hold a payload during interorbital transport, and / or to enable securing during docking or coupling maneuvers. In space missions for repair or maintenance of satellites, the robot arm can be fixed during the working steps to allow precise operations.The apparatus may be configured and / or arranged for on-orbit serving missions where autonomous or semi-autonomous operations are performed. Here, the reliability of the detection device is critical, since malfunctions cannot be corrected by human intervention. The mechanical energy storage enables a safe functionality even in the event of a power failure or communication interruption. In active space waste disposal scenarios, the locking device may help securely hold gripped objects while the combined system is controllably directed into the earth's atmosphere for annealing. The accelerations and structural loads occurring in this case require a particularly robust and reliable fixing.Summarizing and in other words illustrated, the invention thus results / results inter alia in a device and / or a method for clamping a robot arm.In order to fix the robot arm securely without generating additional brake dust and at the same time ensure a reliable braking function, a special mechanism with a pin and a disk can be attached to a robot joint. The disc can have bores at a predefined distance. This predetermined spacing of the bores may eventually define detent positions of the "park" brake.In addition to the disc, a mechanism can be mounted, which mechanism can be built in various ways. For example, the mechanism includes a pin, a spring, and a hold down release mechanism (HDRM). Such an HDRM may be fully qualified for space and the environmental conditions needed. When the HDRM is triggered, the pin moves toward the disk and snaps into the mating holes of the disk. The holes can be approached precisely beforehand, since an absolute position of a robot joint is always given, thus a final position of the robot arm is known.The pin can taper in this case on the one hand, as a result of which twisting is prevented, even with a large amount of force which could be exerted, for example, when the robot arm has gripped another satellite. Another pin shape may be spherical at the tip. This spherical shape allows clamping, but at the same time a possibility of rotating over the braking point with increased non-nominal force exertion of the robot joint / motor. This is made possible by the ball tip not being completely inserted into the disk. If force is now applied, the pin is pushed upwards with the acting spring force and latches again in the next hole in the pane. This also allows subsequent adjustment. This could be necessary if the robot arm still has to be moved despite the clamping.The invention enables a one-time "clamping" at specific joint positions of a robot arm in space, wherein it is possible to extend this method in order to approach further positions of the robot arm under specific conditions. The solution according to the invention has the following advantages in particular:Complete vacuum capability without risk of leakage by dispensing with pneumatic or hydraulic working media.Contamination-free operation without generation of particles by positive instead of frictional action.maintenance-free operation over the entire mission duration by mechanical energy storage.Highest reliability due to simple, proven mechanical principles.bi-directional functionality for both fail-safe and fail-operational configurations.weight optimisation by eliminating complex hydraulic or pneumatic systems.temperature stability in extreme space environments.Redundancy-Capable Execution for Critical Missions.compatibility with established space standards, such as ECSS.reproducible, controlled triggering without pyrotechnic elements.These advantages make the device according to the invention particularly suitable for long-lasting space missions, in which the highest reliability is required with simultaneous freedom from maintenance.Exemplary embodiments of the invention are described in more detail below with reference to figures, in which: FIG. 1 shows a perforated disk of a locking device of a device for holding a robot arm, FIG. 2 shows an apparatus for holding a robot arm with a locking device and a retaining-release device, FIG. 3 shows an apparatus for holding a robot arm with a locking device and a retaining-release device, FIG. 4 shows a locking device of a device for holding a robot arm with a perforated disk and a locking bolt with a ball-segment-shaped end, FIG. 5 shows a locking device of a device for holding a robot arm with a perforated disk and a locking bolt with a conical end, FIG. 6 shows a locking device of a device for holding a robot arm with a perforated disk and two locking bolts, and FIG. 7 shows a robot arm having a plurality of robot members connected to each other by means of robot joints and a device for holding the robot arm.FIG. 1 shows a perforated disk 100 of a locking device of a device for holding a robot arm. The perforated disk 100 has holes, such as hole 102, which are arranged uniformly distributed in the circumferential direction.FIGS. 2 and 3 show an apparatus 200 for holding a robot arm, having a locking device 202 and a restraint release device 204. The locking device 202 has a perforated disk 206, such as perforated disk 100 according to FIG. 1, a locking bolt 208 and a mechanical energy store 210. The locking bolt 208 is displaceable between a release position and a locking position. The mechanical energy store 210 is designed and / or arranged to act on the locking bolt 208 in the direction of the locking position. The retaining-release device 204 is designed and / or arranged to hold the locking bolt 208 in the release position and / or to release a displacement of the locking bolt 208 into the locking position. In FIG. 2, the locking bolt 208 is held in the release position by means of the retaining release device 204, and in FIG. 3, displacement of the locking bolt 208 into the locking position has been released.FIG. 4 shows a locking device 300, such as locking device 202 according to FIGS. 2 and 3, of a device, such as device 200 according to FIGS. 2 and 3, for holding a robot arm having a perforated disk 302, such as perforated disk 206 according to FIGS. 2 and 3, and a locking bolt 304, such as locking bolt 208 according to FIGS. 2 and 3, having a ball-section-shaped end 306.FIG. 5 shows a locking device 400, such as locking device 202 according to FIGS. 2 and 3, of a device, such as device 200 according to FIGS. 2 and 3, for holding a robot arm, having a perforated disk 402, such as perforated disk 206 according to FIGS. 2 and 3, and a locking bolt 404, such as locking bolt 208 according to FIGS. 2 and 3, having a conical end 406.FIG. 6 shows a locking device 500, such as locking device 202 according to FIGS. 2 and 3, of a device, such as device 200 according to FIGS. 2 and 3, for holding a robot arm, having a perforated disk 502, such as perforated disk 206 according to FIGS. 2 and 3, and two locking bolts 504, 506.FIG. 7 shows a robot arm 600 having a plurality of robot members 610, 612, 614, 616, 618 connected to one another by means of robot joints 602, 604, 606, 608 and a device for holding the robot arm. The apparatus includes a locking device, such as locking device 202 of Figures 2 and 3, having a perforated disk and a locking pin for each robotic joint 602, 604, 606, 608.Reference numerals denote reference numerals100 Perforated disk 102 Hole 200 Device 202 Locking device 204 Retention release device 206 Perforated disk 208 Locking bolt 210 Energy store 300 Locking device 302 Perforated disk 304 Locking bolt 306 End 400 Locking device 402 Perforated disk 404 Locking bolt 406 End 500 Locking device 502 Perforated disk 504 Locking bolt 506 Locking bolt 600 Robot arm 602 Robot joint 604 Robot joint 606 Robot joint 608 Robot joint 610 Robot member 612 Robot member 614 Robot member 616 Robot member 618 Robot memberReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2018 110 079 A1

[0004]

Claims

Device (200) for holding a robot arm (600) in at least one predefined position during space travel application, wherein the robot arm (600) comprises a plurality of robot members (610, 612, 614, 616, 618) connected to one another by means of robot joints (602, 604, 606, 608), characterized in that the device (200) comprises a positively acting releasable fixing device (202, 300, 400, 500).Device (200) according to claim 1, characterised in that the fixing device (202, 300, 400, 500) has at least one perforated disc (100, 206, 302, 402, 502) and at least one locking bolt (208, 304, 404, 504, 506) which can be displaced between a release position and a locking position.The device (200) according to claim 2, characterized in that the at least one perforated disk (100, 206, 302, 402, 502) comprises a plurality of holes (102).Device (200) according to at least one of Claims 2 to 3, characterized in that the at least one locking bolt (208, 304, 404, 504, 506) has a conical or spherical-segment-shaped end (306, 406) assigned to the at least one perforated disc (100, 206, 302, 402, 502).Device (200) according to at least one of Claims 2 to 4, characterized in that the fixing device (202, 300, 400, 500) has at least one mechanical energy store (210) which is designed and / or arranged to load the at least one locking bolt (208, 304, 404, 504, 506) in the direction of the locking position.Device (200) according to at least one of claims 2 to 5, characterised in that the device (200) has at least one retaining release device (204) which is designed and / or arranged to hold the at least one locking bolt (208, 304, 404, 504, 506) in the release position and / or to release displacement into the locking position.A robotic arm (600) for aerospace application, the robotic arm (600) comprising a plurality of robotic members (610, 612, 614, 616, 618) connected together by robotic joints (602, 604, 606, 608), characterized in that the robotic arm (600) comprises a device (200) according to at least one of the preceding claims.Spacecraft, characterized in that the spacecraft comprises at least one robot arm (600) according to claim 7.

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