coupling of a redundant manipulator with a virtual reality environment to enhance human robot cooperation

Abstract The current trend in manufacturing is to obtain a flexible work cell in which human and robot can safely interact and collaborate. Virtual Reality (VR) represents an effective tool capable of simulating such complex systems with a high level of immersion. In order to take advantage of VR technologies to study Human-Robot Cooperation (HRC), a digital model of a redundant manipulator (KUKA LBR iiwa) has been developed starting with kinematic modeling and then coupled with the real robot. This approach allows simulating HRC in several scenarios, to reproduce the safe behavior on the real robot, as well as to train operators

Online analysis of oxygen inside silicon-glass microreactors with integrated optical sensors

AbstractA powerful online analysis set-up for oxygen measurements within microfluidic devices is presented. It features integration of optical oxygen sensors into microreactors, which enables contactless, accurate and inexpensive readout using commercially available oxygen meters via luminescent lifetime measurements in the frequency domain (phase shifts). The fabrication and patterning of sensor layers down to a size of 100μm in diameter is performed via automated airbrush spraying and was used for the integration into silicon-glass microreactors. A novel and easily processable sensor material is also presented and consists of a polystyrene- silicone rubber composite matrix with embedded palladium(II) or platinum(II) meso-tetra(4-fluorophenyl) tetrabenzoporphyrin (PdTPTBPF and PtTPTBPF) as oxygen sensitive dye. The resulting sensor layers have several advantages such as being excitable with red light, emitting in the near-infrared spectral region, being photostable and covering a wide oxygen concentration range. The trace oxygen sensor (PdTPTBPF) in particular shows a resolution of 0.06–0.22hPa at oxygen concentrations lower than 20hPa (<2% oxygen) and the normal range oxygen sensor (PtTPTBPF) shows a resolution of 0.2–0.6hPa at low oxygen concentrations (<50hPa) and 1–2hPa at ambient air oxygen concentrations. The sensors were integrated into different silicon-glass microreactors which were manufactured using mass production compatible processes. The obtained microreactors were applied for online monitoring of enzyme transformations, including d-alanine or d-phenylalanine oxidation by d-amino acid oxidase, and glucose oxidation by glucose oxidase

A cadaver‑based biomechanical model of acetabulum reaming for surgical virtual reality training simulators

Total hip arthroplasty (THA) is a highly successful surgical procedure, but complications remain, including aseptic loosening, early dislocation and misalignment. These may partly be related to lacking training opportunities for novices or those performing THA less frequently. A standardized training setting with realistic haptic feedback for THA does not exist to date. Virtual Reality (VR) may help establish THA training scenarios under standardized settings, morphology and material properties. This work summarizes the development and acquisition of mechanical properties on hip reaming, resulting in a tissue-based material model of the acetabulum for force feedback VR hip reaming simulators. With the given forces and torques occurring during the reaming, Cubic Hermite Spline interpolation seemed the most suitable approach to represent the nonlinear forcedisplacement behavior of the acetabular tissues over Cubic Splines. Further, Cubic Hermite Splines allowed for a rapid force feedback computation below the 1 ms hallmark. The Cubic Hermite Spline material model was implemented using a three-dimensional-sphere packing model. The resulting forces were delivered via a human–machine-interaction certified KUKA iiwa robotic arm used as a force feedback device. Consequently, this novel approach presents a concept to obtain mechanical data from high-force surgical interventions as baseline data for material models and biomechanical considerations; this will allow THA surgeons to train with a variety of machining hardness levels of acetabula for haptic VR acetabulum reaming

A versatile optode system for oxygen, carbon dioxide, and pH measurements in seawater with integrated battery and logger

Herein, we present a small and versatile optode system with integrated battery and logger for monitoring of O-2, pH, and pCO(2) in seawater. Three sensing materials designed for seawater measurements are optimized with respect to dynamic measurement range and long-term stability. The spectral properties of the sensing materials were tailored to be compatible with a commercially available laboratory oxygen logger that was fitted into a pressure housing. Interchangeable sensor caps with appropriate "sensing chemistry" are conveniently attached to the end of the optical fiber. This approach allows using the same instrument for multiple analytes, which offers great flexibility and minimizes hardware costs. Applications of the new optode system were demonstrated by recording depth profiles for the three parameters during a research cruise in the Baltic Sea and by measuring surface water transects of pH. The optode was furthermore used to monitor the concentration of dissolved oxygen in a seagrass meadow in the Limfjord, Denmark, and sensor packages consisting of pO(2), pH, and pCO(2) were deployed in the harbors of Kiel, Germany, and Southampton, England, for 6 d. The measurements revealed that the system can resolve typical patterns in seawater chemistry related to spatial heterogeneities as well as temporal changes caused by biological and tidal activity

Von Landesexzellenzinitiativen zu Vernetzung, Digitalisierung, Industrie 4.0: Vortrag gehalten bei Vernetzung, Digitalisierung, Industrie 4.0: Verheißung oder Grund zur Sorge?, 8. November 2016, Dresden

Ergebnispräsentation der Exzellenzinitiative des Freistaats Sachse

Using Virtual Prototyping Technologies to Evaluate Human-Machine-Interaction Concepts

Innovative products are interacting with the users based on smart sensors and algorithms. Logistics as one example is changing when automated guided vehicles are integrated in the process, supporting or even replacing workers. The way these products are interacting with humans and how they react to certain situations, will determine usability and user experience and therefore the success of use. Developing such products is based on innovative concepts that need to be evaluated and refined at early project stages. Using virtual-reality based user scenarios is one adequate option to do so. This paper describes technical as well as study-based approaches on how potential concepts are realized as virtual prototypes and evaluated by real users. It concludes with the evaluation results of a pilot study but also with general limitations and benefits as best practice advice for this kind of virtual prototyping techniques

Using Virtual Prototyping Technologies to Evaluate Human-Machine-Interaction Concepts

Innovative products are interacting with the users based on smart sensors and algorithms. Logistics as one example is changing when automated guided vehicles are integrated in the process, supporting or even replacing workers. The way these products are interacting with humans and how they react to certain situations, will determine usability and user experience and therefore the success of use. Developing such products is based on innovative concepts that need to be evaluated and refined at early project stages. Using virtual-reality based user scenarios is one adequate option to do so. This paper describes technical as well as study-based approaches on how potential concepts are realized as virtual prototypes and evaluated by real users. It concludes with the evaluation results of a pilot study but also with general limitations and benefits as best practice advice for this kind of virtual prototyping techniques

Influence of the stiffness of burnishing tools on process force and surface quality of EN AW-2007 and C45 workpieces

Burnishing is a highly efficient surface finishing process, which is also more sustainable compared to grinding. Such processed surfaces are characterized by a low roughness and an increased hardness. In recent years, the interest in the process grew due to the steady adoption on flat and free-form surfaces. Especially the latter may benefit from a soft burnishing tool, due to the nearly constant burnishing force and therefore a less strong interaction with geometric imperfections of the free-form surface. In this paper, the influence of the burnishing tool stiffness on the surface features indent, bulge and roughness are shown. Several low and one high stiffness burnishing tool were investigated. As evaluation data, the burnishing force and the finished surface were measured. As shown in this paper, soft tools result in a constant force and can improve surface quality

Augmented-Reality-unterstütztes, prädiktives Condition-Monitoring-System für Werkzeugmaschinen

Reaktive Instandhaltungsmodelle führen oftmals zu nicht planbaren Produktionsunterbrechungen, präventive Modelle mit festen Wartungsintervallen verschenken evtl. noch vorhandene Abnutzungsvorräte. Zudem werden bereits vorhandene bzw. sich anbahnende Fehlfunktionen der Maschine durch das Bedien- und Wartungspersonal vielfach fehlinterpretiert oder ignoriert. Beide Problemkreise generieren in der Serien- und Massenfertigung auf den Stückpreis unmittelbar durchschlagende, die Wettbewerbsfähigkeit negativ beeinflussende Kosten. Eine auf Steuerungs- und Sensordaten basierende objektive Bewertung des aktuellen Verschleißzustandes, verbunden mit einer statistik und/oder modellgestützten Vorhersage künftiger Ausfallwahrscheinlichkeiten sowie einer verständlichen Augmented-Reality-gestützten Visualisierung der Baugruppenzustände und Ableitung entsprechender Handlungs- und Serviceanweisungen, ermöglicht eine Minimierung des Einflusses derart kostentreibender Faktoren. Die modulare Systemarchitektur ermöglicht eine Anpassung an das spezifische Verschleiß- und Ausfallverhaltender zu überwachenden Maschinen

Optimization of characteristic diagram based thermal error compensation via load case dependent model updates

The compensation of thermal errors in machine tools is one of the major challenges in ensuring positioning accuracy during cutting operations. There are numerous methods for both the model-based estimation of the thermal tool center point (TCP) deflection and for controlling the thermal or thermo-elastic behavior of the machine tool. One branch of thermal error estimation uses regression models to map temperature sensors directly onto the TCP-displacement. This can, e.g., be accomplished using linear models, artificial neural networks or characteristic diagrams. One of the main limitations of these models is the poor extrapolation behavior with regard to untrained load cases. This paper presents a new method for updating characteristic diagram based compensation models by combining existing models with new measurements. This allows the optimization of the compensation for serial production load cases without the effort of computing a new model. The new method was validated on a 5-axis machining center