Differential game theory for versatile physical human-robot interaction

The last decades have seen a surge of robots working in contact with humans. However, until now these contact robots have made little use of the opportunities offered by physical interaction and lack a systematic methodology to produce versatile behaviours. Here, we develop an interactive robot controller able to understand the control strategy of the human user and react optimally to their movements. We demonstrate that combining an observer with a differential game theory controller can induce a stable interaction between the two partners, precisely identify each other’s control law, and allow them to successfully perform the task with minimum effort. Simulations and experiments with human subjects demonstrate these properties and illustrate how this controller can induce different representative interaction strategies

Social Cognition for Human-Robot Symbiosis—Challenges and Building Blocks

The next generation of robot companions or robot working partners will need to satisfy social requirements somehow similar to the famous laws of robotics envisaged by Isaac Asimov time ago (Asimov, 1942). The necessary technology has almost reached the required level, including sensors and actuators, but the cognitive organization is still in its infancy and is only partially supported by the current understanding of brain cognitive processes. The brain of symbiotic robots will certainly not be a “positronic” replica of the human brain: probably, the greatest part of it will be a set of interacting computational processes running in the cloud. In this article, we review the challenges that must be met in the design of a set of interacting computational processes as building blocks of a cognitive architecture that may give symbiotic capabilities to collaborative robots of the next decades: (1) an animated body-schema; (2) an imitation machinery; (3) a motor intentions machinery; (4) a set of physical interaction mechanisms; and (5) a shared memory system for incremental symbiotic development. We would like to stress that our approach is totally un-hierarchical: the five building blocks of the shared cognitive architecture are fully bi-directionally connected. For example, imitation and intentional processes require the “services” of the animated body schema which, on the other hand, can run its simulations if appropriately prompted by imitation and/or intention, with or without physical interaction. Successful experiences can leave a trace in the shared memory system and chunks of memory fragment may compete to participate to novel cooperative actions. And so on and so forth. At the heart of the system is lifelong training and learning but, different from the conventional learning paradigms in neural networks, where learning is somehow passively imposed by an external agent, in symbiotic robots there is an element of free choice of what is worth learning, driven by the interaction between the robot and the human partner. The proposed set of building blocks is certainly a rough approximation of what is needed by symbiotic robots but we believe it is a useful starting point for building a computational framework

The Role of Roles: Physical Cooperation between Humans and Robots

Since the strict separation of working spaces of humans and robots has experienced a softening due to recent robotics research achievements, close interaction of humans and robots comes rapidly into reach. In this context, physical human–robot interaction raises a number of questions regarding a desired intuitive robot behavior. The continuous bilateral information and energy exchange requires an appropriate continuous robot feedback. Investigating a cooperative manipulation task, the desired behavior is a combination of an urge to fulfill the task, a smooth instant reactive behavior to human force inputs and an assignment of the task effort to the cooperating agents. In this paper, a formal analysis of human–robot cooperative load transport is presented. Three different possibilities for the assignment of task effort are proposed. Two proposed dynamic role exchange mechanisms adjust the robot’s urge to complete the task based on the human feedback. For comparison, a static role allocation strategy not relying on the human agreement feedback is investigated as well. All three role allocation mechanisms are evaluated in a user study that involves large-scale kinesthetic interaction and full-body human motion. Results show tradeoffs between subjective and objective performance measures stating a clear objective advantage of the proposed dynamic role allocation scheme

Regrowth on Patterned Epitaxial Layers for Fabrication of Optoelectronic Integrated Circuits by Molecular Beam Epitaxy

For the fabrication of high-bit-rate monolithic integrated photoreceiver OEICs, which find application in optical telecommunication networks (1.55 µm), GaInAsP/InP layers that are grown by metal-organic vapour phase epitaxy (MOVPE) and structured photolithographically, are regrown in a second growth run with AlInAs/GaInAs layers for High Electron Mobility Transistors (HEMT) by molecular beam epitaxy (MBE). Adversely, residual chemical contaminations were determined on the surfaces to be overgrown and, consequently, suitable preparation methods were elaborated. Investigations of the morphology and alloy composition in the vicinity of mesa edges provided supplemental information about the MBE growth kinetics of AlInAs and GaInAs materials. The MBE growth parameters were suited to optimize the material quality of integrated HEMT layers and to avoid degradation of the overgrown photodiode and semi-insulating light waveguide layers. The achieved device characteristics of the completed photoreceivers with data rates up to 35 Gbit/s demonstrate the success of the elaborated MBE regrowth process. Zur Herstellung hochbitratiger, monolithisch integrierter Photoempfänger-OEICs für optische Weitverkehrsnetze (1.55 µm) werden mit metallorganischer Gasphasenepitaxie (MOVPE) gewachsene Photodioden- und semi-isolierende Lichtwellenleiterschichten aus GaInAsP/InP, nach einer photolithographischen Strukturierung, in einem zweiten Wachstumsschritt mittels Molekularstrahl-Epitaxie (MBE) mit dem Schichtenpaket für AlInAs/GaInAs-Heterostruktur-Feldeffekttransistoren (HFET/HEMT) überwachsen. Um von den zu überwachsenden Oberflächen störende chemische Verunreinigungen zu beseitigen, werden geeignete Präparationsmethoden zum Einsatz gebracht. Informationen zur MBE-Wachstumskinetik von AlInAs- und GaInAs-Schichten werden im Rahmen von Untersuchungen der Morphologie und Legierungszusammensetzung an Strukturkanten gewonnen. Die von den MBE-Wachstumsparametern abhängigen Materialeigenschaften der integrierten HEMT-Schichten sind soweit optimiert, daß eine Degradation der überwachsenen Schichten vermieden wird. Die Bauelementeigenschaften der Photoempfänger mit Übertragungsraten von 35 Gbit/s belegen den Erfolg des MBE-Wachstumsschritts

Exploring the design space of haptic assistants: The assistance policy module

Haptic assistants augment user commands to facilitate manipulation and to increase task performance. The strength of assistance, also referred to as assistance level, is one of the main design factors. While existing implementations mainly realize fixed assistance levels that are selected with respect to one design objective, we introduce an assistance policy module that dynamically changes assistance levels and can incorporate multiple performance measures. The design space of this assistance policy module is systematically analyzed and three design factors, 1) performance criteria, 2) performance reference, and 3) assistance policy, are identified. Different implementations of the assistance policy module are compared for a scenario involving guiding virtual fixtures. A single-user evaluation is used to illustrate the effect of the different implementations on the determined assistance levels, and a multi-user study allows for a statistical comparison of them. Results show that adaptive assistance policies can outperform constant assistance policies, switching assistance policies have advantages over continuously adapting policies, a multi-criteria performance measure should be favored if there is no single criterion that has an outstanding priority, and the selection of the performance reference is highly application dependent. © 2013 IEEE

Model-Mediated Teleoperation for Multi-Operator Multi-Robot Systems

Abstract — Knowledge about the remote environment can be used in the control law to improve robustness and fidelity of haptic teleoperation systems. Model-mediated teleoperation adopts this idea by rendering an estimated model of the remote environment on local site instead of transmitting force/velocity flows. In this paper, we extend the original model-mediated teleoperation approach to multi-operator multi-robot teleoperation systems. A theoretic robustness and fidelity analysis is conducted. The theoretical results show a superior performance of the proposed method compared to a classic bilateral approach. Experimental results confirm the practical efficiency of the presented approach. I