The newly developed versatile milling kinematics with hybrid drive on a linear axis machines a carbon fiber-reinforced polymer (CFRP) vertical tail airplane on a 1:1 scale with extreme precision. Provide | Fraunhofer IFAM
The simply these days completed Lower Saxony LuFo mission, “Robots Made in Lower Saxony 2” (RoMaNi 2) has reportedly closed the outlet between industrial robots and machine devices, attaining a novel kind of drivetrain that enable versatile, setting pleasant machine of provides — from composites to metals — with a producing tolerance of as a lot as 0.1 millimeter. R&D work was led by Fraunhofer IFAM (Stade, Germany) together with Broetje-Automation GmbH, Hexagon Aicon Etalon GmbH and Siemens AG, along with associated companions Airbus Operations GmbH and A&T Service GmbH.
Inside the mission, two robotic kinematics designed for machining have been examined intimately, optimized by control-side settings and metrological help for path-accurate processes and examined on a 1:1 scale using real-life aviation features. As part of the RoMaNi 2 mission, researchers at Fraunhofer IFAM have been able to completely assemble the prototype kinematics with a model new kind of hybrid drive that had already been developed inside the Flexmatik 4.1 mission, put it into operation and try it in machining processes. RoMaNi 2 concluded with the high-precision milling of an Airbus vertical tail airplane and a steel check out merchandise.
Versatile serial industrial robots vs. stationary, high-precision machine devices
Currently, novel manufacturing processes have led to extra developments inside the design freedom and structural integrity of near-net kind carbon fiber-reinforced polymer (CFRP) elements in aircraft manufacturing. Attributable to monetary and technical requirements, high-precision postprocessing of giant elements inside the meter fluctuate with tolerances inside the submillimeter fluctuate is usually carried out with large, gantry-designed machine devices. However, these machines could also be considerably large counting on their kinematic development, which often dictates the format of the manufacturing providers and limits their talent to react flexibly to modifications inside the manufacturing course of.
One other is the financial robotic, along with workspace development by way of a movable platform, the arrange of quite a lot of robots or the utilization of additional translatory axes equal to linear axes. Compared with gantry strategies or machine devices, this machine concept is slightly extra space-saving and is not economically tied to explicit particular person large elements. In addition to, no explicit foundations are required, which facilitates the long term adaption of producing traces.
Inside the mission, path accuracy for large elements (as a lot as 7 meters) was improved by 0.15 millimeter.
Although industrial robots have already been effectively used inside the machining of thin aerospace shell elements, rising their robustness to course of forces and their talent to cope with increasingly demanding machining duties is the next step for the rising use of enterprise robots inside the manufacturing of giant aerospace elements.
Industrial robotic dynamic habits enhancements
Automation and manufacturing experience specialists from Fraunhofer IFAM assembled and investigated the prototype of a serial robotic. The in-house developed kinematics are basically designed to fulfill the requirements of processes with extreme path accuracy. The intention was to realize manufacturing tolerances of on the very least ±0.1 millimeter when machining large elements.
This prototype robotic, along with the linear axis, was developed as part of the Flexmatik 4.1 mission, which ended with the fabrication of all elements. The assembly of the kinematics, commissioning, control-side optimization and extra enchancment, along with intensive investigation of the robotic kinematics, have now been effectively completed inside the RoMaNi 2 mission. Accuracy exams confirmed that the aim of 0.1 millimeter was achieved.
A key element in enhancing the prototype robotic’s dynamic habits, together with structural optimization, was the utilization of an progressive drive concept in lower joint axes. By using an additional direct drive parallel to the usual gear drive, companions remember {{that a}} torque could also be utilized instantly on the load facet. This hybrid drive concept combines the chance of compensating for undesirable outcomes of the gearbox and damping high-frequency excitations, whereas on the same time guaranteeing extreme energy effectivity in static and quasi-static load situations.
Kinematics are managed by a Siemens Sinumerik One controller, avoiding the need for retraining on new administration strategies. Inside the RoMaNi 2 mission, hybrid drive administration elements have been extra developed so that the drive’s full potential could be utilized inside the industrial administration system.
Intensive utility fluctuate
In line with companions, the combination of serial articulated arm kinematics with a linear axis offers advantages over large gantry strategies and completely different machining strategies. First, the linear axis, with a smaller arrange space and modular design, makes the system extraordinarily versatile. Second, the utilization of two preloaded rack and pinion drives compensates for reversal outcomes and achieves a sufficiently extreme drive stiffness of the linear axis carriage for path-accurate robotic processes; the linear axis’ extreme structural stiffness does unlikely affect robotic accuracy whatever the huge lever arms to the load utility stage.
Inside the mission, path accuracy for large elements (as a lot as 7 meters) was improved by 0.15 millimeter. Fraunhofer IFAM researchers think about even elevated accuracy could also be achieved by compensating for various static influencing parts, equal to temperature, pretty than compensating for various dynamic outcomes.
The utilization of direct drives significantly improves reference monitoring habits and disturbance rejection of the serial robotic kinematics at axis diploma. Direct mechanical transmission of the motor torques to the kinematics moreover permits elevated jerk adjustment of all lower joint axes — that’s reported to be 10-100 situations elevated than typical robots with servo drives and subsequently offers potential for rising productiveness. In addition to, a giant enhance in path accuracy might also be demonstrated at extreme path speeds. At a feed cost of 10 meters/minute, a path accuracy inside the fluctuate of the beforehand recorded static accuracy could also be demonstrated. Damping of the first eigenmodes — induced by the gear drives — moreover offers potential for improved disturbance rejection.
Subsequent steps
Researchers at Fraunhofer IFAM, together with companions from enterprise, intend to extra develop this experience until it is ready for sequence manufacturing. There could also be a wide range of features for industrial robots with hybrid drives: Along with a linear axis, the spectrum ranges from machining duties equal to fiber-reinforced composite constructions and aluminum alloys, to the machining of extra sturdy provides, equal to steel or titanium.