Theoretical and practical development of control approaches for redundantly actuated parallel kinematic machines

Die konsequente Weiterentwicklung parallelkinematischer Maschinen (PKM) führt auf eine strukturelle Erweiterung in Form einer Antriebsredundanz. Die wesentlichen Vorteile der Antriebsredundanz sind beispielsweise die Kompensation von Singularitäten im Arbeitsraum, eine erhöhte Endeffektor-Steifigkeit und eine optimale Verteilung der Antriebskräfte. Redundant angetriebene PKM (RA-PKM) sind darum prädestiniert für hochdynamische Pick-and-Place-Bewegungsaufgaben und neue Maschinenkonzepte. Die vorliegende Arbeit befasst sich mit der Frage, welche Konzepte und Verfahren für die Regelung der RA-PKM geeignet sind. Dabei zeigt sich, dass die Beschreibung in Endeffektor-Koordinaten, die Verwendung eines Störgrößenbeobachters auf der Basis des generalisierten Impulses sowie eine modellprädiktive Regelung sehr gute Ergebnisse hinsichtlich der Genauigkeit und des Implementierungs- und Rechenaufwandes ergeben. Dies gilt insbesondere, wenn große Reibkräfte z. B. in den Antrieben zu berücksichtigen sind. Deshalb ist dieses Verfahren für die industrielle Anwendung besonders geeignet. Da für alle hier betrachteten Regelungsverfahren ein mathematisches Modell erforderlich ist, nimmt die Beschreibung der Bewegungsgleichungen in unterschiedlichen Koordinaten einen breiten Raum der Arbeit ein. Es werden die Vor- und Nachteile der verschiedenen Beschreibungsformen wie z. B. die verschiedenen Arten der Singularitäten und die Eliminierung der Zwangskräfte mit Hilfe von Orthogonalprojektionen ausführlich dargestellt. Dabei wurde ein neuartiger Zugang für die Projektion der Bewegungsgleichungen in Endeffektor-Koordinaten hergeleitet. Als erstes Regelungskonzept wird die dezentrale Regelung betrachtet. Es wird gezeigt, wie die hier üblicherweise auftretenden antagonistischen Kräfte mit Hilfe eines Filters kompensiert werden können. Im Anschluss daran wird die große Klasse der modellbasierten Regelungen in den unterschiedlichen Koordinaten untersucht, wobei ein sogenannter Computed Torque Regler (CTC), d. h. die Verwendung einer Vorsteuerung in Form der inversen Dynamik, und ein Augmented PD-Regler (APD) zum Einsatz kommen. Die Gelenkgeschwindigkeiten werden mit Hilfe eines High-Gain-Beobachters und die Störgrößen mit Hilfe eines Störgrößenbeobachters rekonstruiert. Zum Schluss wird die schon erwähnte nichtlineare modellprädiktive Regelung in Endeffektor-Koordinaten beschrieben, wobei der zukünftige Trajektorienfehler durch eine optimale Stellgröße minimiert wird. Die resultierende Reglerstruktur hat die Form eines klassischen APD-Reglers mit variablen Verstärkungen. Die Reglereinstellung erfolgt durch die Prädiktion vollkommen automatisch. Die entwickelten Regler und Methoden wurden anhand eines ebenen Mechanismus mit zwei Freiheitsgraden unter Verwendung industrieller Torque-Motoren erprobt.The consistent further development of parallel kinematics machines (PKM) lead to a structural extension in terms of actuation redundancy. The major advantages of redundant actuation are for example the compensation of singularities in workspace, an increased end-effector stiffness and an optimal distribution of the control forces. Therefore redundantly actuated PKM (RA-PKM) are intended for high speed pick-and-place tasks and new machine concepts. This research work addresses the question which concepts and methods are qualified for the control of RA-PKM. It has been found that a formulation of motion equations in end-effector coordinates, the use of a disturbance observer based on the general momentum as well as a model predictive controller lead to very well results in terms of accuracy, implementation and computing time. This applies particularly, if large friction losses as they occur in drives, have to be taken into account. Therefore this method is particularly suitable for industrial applications. Since a mathematical model is needed for all proposed control schemes, the determination of motion equations in terms of different coordinate formulations makes up a large part of this report. The advantages and disadvantages, such as the different types of singularities and the elimination of constraint forces by means of orthogonal projections are elaborated. Although a novel approach for the projection of motion equations in terms of end effector coordinates is derived. At first, the decentralized control scheme is considered. It will be shown that antagonistic Forces which are inherent to the control-scheme can be compensated by means of a filter. Afterwards, the large class of model-based control schemes is reviewed in which a so called computed torque controller (CTC), i.e. the use of a feed-forward control in the form of the inverse dynamics, and an augmented PD (APD) controller are used. The joint velocities where observed by means of a high gain observer and the disturbances by means of a disturbance observer. Finally, the already mentioned nonlinear model predictive control scheme in terms of end-effector coordinates which minimizes the future trajectory error due to an optimal actuating variable is described. The resulting approach can be structurally incorporated into an APD controller with variable gains. The controller setup is an automated process due to the prediction. The proposed control schemes and methods where experimentally validated by means of a two degree of freedom planar mechanism with industrial torque motors

PARA-ENGINEER - Parallelroboter-Baukasten für die Ausbildung in Technik und Robotik

Für die Integration parallelkinematischer Manipulatoren in die Lehre der Hochschule Heilbronn, wurde mit dem Projekt „PARA-ENGINEER - Parallel Robot Assembly Kit for Educational Engineering and Robotics“ ein Modellbaukasten für Parallelroboter entwickelt. Mit dem Baukasten sollen Studierende in die Lage versetzt werden, verschiedene Themen im Bereich der Parallelkinematik, nicht nur in der Simulation, sondern auch am realen Modell zu erproben. Mit der Plattform lassen sich verschiedene Parallelroboter mit unterschiedlicher Software und Hardware realisieren und praktisch erproben. Zum aktuellen Zeitpunkt besteht der Baukasten aus drei gängigen parallelkinematischen Manipulatoren. Das Baukastenprinzip wurde entwickelt, um unter anderem in der Laborveranstaltung „Parallelkinematische Systeme“ hergeleitete Vorwärts- und Rückwärtskinematik sowie die Trajektorienplanung zu testen. Das Ziel des Projekts bestand auch darin, dass durch wenig Einzelteile eine Vielzahl unterschiedlicher Parallelroboter realisiert werden können. Die Elektronik der Parallelroboter basiert auf einem Raspberry Pi 4 mit 8 GB Speicher. Dieser wurde mit selbstentwickelten Platinen für die Ansteuerung der Schrittmotoren und für die Sensoren erweitert

Development of the CMS detector for the CERN LHC Run 3

International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

Development of the CMS detector for the CERN LHC Run 3

International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

Development of the CMS detector for the CERN LHC Run 3

International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

Development of the CMS detector for the CERN LHC Run 3

International audienceSince the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

Development of the CMS detector for the CERN LHC Run 3

Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger

Development of the CMS detector for the CERN LHC Run 3

Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger