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result(s) for
"Mohan, Vishwanathan"
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Social Cognition for Human-Robot Symbiosis—Challenges and Building Blocks
by
Morasso, Pietro
,
Mohan, Vishwanathan
,
Sciutti, Alessandra
in
Cognition & reasoning
,
Cognitive ability
,
cognitive architecture
2018
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.
Journal Article
Revisiting the Body-Schema Concept in the Context of Whole-Body Postural-Focal Dynamics
by
Morasso, Pietro
,
Mohan, Vishwanathan
,
Zenzeri, Jacopo
in
body schema
,
Cognition
,
Computer applications
2015
The body-schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert) but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the equilibrium-point hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory-motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability.
Journal Article
Imitation Learning from a Single Demonstration Leveraging Vector Quantization for Robotic Harvesting
by
Inglezou, Myrto
,
Mohan, Vishwanathan
,
Porichis, Antonios
in
Automation
,
Cameras
,
Cognitive tasks
2024
The ability of robots to tackle complex non-repetitive tasks will be key in bringing a new level of automation in agricultural applications still involving labor-intensive, menial, and physically demanding activities due to high cognitive requirements. Harvesting is one such example as it requires a combination of motions which can generally be broken down into a visual servoing and a manipulation phase, with the latter often being straightforward to pre-program. In this work, we focus on the task of fresh mushroom harvesting which is still conducted manually by human pickers due to its high complexity. A key challenge is to enable harvesting with low-cost hardware and mechanical systems, such as soft grippers which present additional challenges compared to their rigid counterparts. We devise an Imitation Learning model pipeline utilizing Vector Quantization to learn quantized embeddings directly from visual inputs. We test this approach in a realistic environment designed based on recordings of human experts harvesting real mushrooms. Our models can control a cartesian robot with a soft, pneumatically actuated gripper to successfully replicate the mushroom outrooting sequence. We achieve 100% success in picking mushrooms among distractors with less than 20 min of data collection comprising a single expert demonstration and auxiliary, non-expert, trajectories. The entire model pipeline requires less than 40 min of training on a single A4000 GPU and approx. 20 ms for inference on a standard laptop GPU.
Journal Article
Towards a learnt neural body schema for dexterous coordination of action in humanoid and industrial robots
by
Ajaz Ahmad Bhat
,
Morasso, Pietro
,
Eitzinger, Christian
in
Active control
,
Architecture
,
Computer simulation
2017
During any goal oriented behavior the dual processes of generation of dexterous actions and anticipation of the consequences of potential actions must seamlessly alternate. This article presents a unified neural framework for generation and forward simulation of goal directed actions and validates the architecture through diverse experiments on humanoid and industrial robots. The basic idea is that actions are consequences of an simulation process that animates the internal model of the body (namely the body schema), in the context of intended goals/constraints. Specific focus is on (a) Learning: how the internal model of the body can be acquired by any robotic embodiment and extended to coordinated tools; (b) Configurability: how diverse forward/inverse models of action can be ‘composed’ at runtime by coupling/decoupling different body (body \\[+\\] tool) chains with task relevant goals and constraints represented as multi-referential force fields; and (c) Computational simplicity: how both the synthesis of motor commands to coordinate highly redundant systems and the ensuing forward simulations are realized through well-posed computations without kinematic inversions. The performance of the neural architecture is demonstrated through a range of motor tasks on a 53-DoFs robot iCub and two industrial robots performing real world assembly with emphasis on dexterity, accuracy, speed, obstacle avoidance, multiple task-specific constraints, task-based configurability. Putting into context other ideas in motor control like the Equilibrium Point Hypothesis, Optimal Control, Active Inference and emerging studies from neuroscience, the relevance of the proposed framework is also discussed.
Journal Article
Passive Motion Paradigm: An Alternative to Optimal Control
by
Morasso, Pietro
,
Mohan, Vishwanathan
in
Cognitive ability
,
Cognitive architectures
,
Computational neuroscience
2011
IN THE LAST YEARS, OPTIMAL CONTROL THEORY (OCT) HAS EMERGED AS THE LEADING APPROACH FOR INVESTIGATING NEURAL CONTROL OF MOVEMENT AND MOTOR COGNITION FOR TWO COMPLEMENTARY RESEARCH LINES: behavioral neuroscience and humanoid robotics. In both cases, there are general problems that need to be addressed, such as the \"degrees of freedom (DoFs) problem,\" the common core of production, observation, reasoning, and learning of \"actions.\" OCT, directly derived from engineering design techniques of control systems quantifies task goals as \"cost functions\" and uses the sophisticated formal tools of optimal control to obtain desired behavior (and predictions). We propose an alternative \"softer\" approach passive motion paradigm (PMP) that we believe is closer to the biomechanics and cybernetics of action. The basic idea is that actions (overt as well as covert) are the consequences of an internal simulation process that \"animates\" the body schema with the attractor dynamics of force fields induced by the goal and task-specific constraints. This internal simulation offers the brain a way to dynamically link motor redundancy with task-oriented constraints \"at runtime,\" hence solving the \"DoFs problem\" without explicit kinematic inversion and cost function computation. We argue that the function of such computational machinery is not only restricted to shaping motor output during action execution but also to provide the self with information on the feasibility, consequence, understanding and meaning of \"potential actions.\" In this sense, taking into account recent developments in neuroscience (motor imagery, simulation theory of covert actions, mirror neuron system) and in embodied robotics, PMP offers a novel framework for understanding motor cognition that goes beyond the engineering control paradigm provided by OCT. Therefore, the paper is at the same time a review of the PMP rationale, as a computational theory, and a perspective presentation of how to develop it for designing better cognitive architectures.
Journal Article
Teaching a humanoid robot to draw ‘Shapes’
by
Chakravarthy, V. Srinivasa
,
Morasso, Pietro
,
Mohan, Vishwanathan
in
Architecture
,
Artificial Intelligence
,
Catastrophe theory
2011
The core cognitive ability to perceive and synthesize ‘shapes’ underlies all our basic interactions with the world, be it shaping one’s fingers to grasp a ball or shaping one’s body while imitating a dance. In this article, we describe our attempts to understand this multifaceted problem by creating a primitive shape perception/synthesis system for the baby humanoid iCub. We specifically deal with the scenario of iCub gradually learning to draw or scribble shapes of gradually increasing complexity, after observing a demonstration by a teacher, by using a series of self evaluations of its performance. Learning to imitate a demonstrated human movement (specifically, visually observed end-effector trajectories of a teacher) can be considered as a special case of the proposed computational machinery. This architecture is based on a loop of transformations that express the embodiment of the mechanism but, at the same time, are characterized by scale invariance and motor equivalence. The following transformations are integrated in the loop: (a) Characterizing in a compact, abstract way the ‘shape’ of a demonstrated trajectory using a finite set of critical points, derived using catastrophe theory: Abstract Visual Program (AVP); (b) Transforming the AVP into a Concrete Motor Goal (CMG) in iCub’s egocentric space; (c) Learning to synthesize a continuous
virtual trajectory
similar to the demonstrated shape using the discrete set of critical points defined in CMG; (d) Using the
virtual trajectory
as an attractor for iCub’s internal body model, implemented by the Passive Motion Paradigm which includes a forward and an inverse motor model; (e) Forming an Abstract Motor Program (AMP) by deriving the ‘shape’ of the self generated movement (forward model output) using the same technique employed for creating the AVP; (f) Comparing the AVP and AMP in order to generate an internal performance score and hence closing the learning loop. The resulting computational framework further combines three crucial streams of learning: (1) motor babbling (self exploration), (2) imitative action learning (social interaction) and (3) mental simulation, to give rise to sensorimotor knowledge that is endowed with seamless compositionality, generalization capability and body-effectors/task independence. The robustness of the computational architecture is demonstrated by means of several experimental trials of gradually increasing complexity using a state of the art humanoid platform.
Journal Article
A neural mechanism of synergy formation for whole body reaching
by
Morasso, Pietro
,
Mohan, Vishwanathan
,
Zenzeri, Jacopo
in
Bioinformatics
,
Biomechanical Phenomena
,
Biomedical and Life Sciences
2010
The present study proposes a computational model for the formation of whole body reaching synergy, i.e., coordinated movements of lower and upper limbs, characterized by a focal component (the hand must reach a target) and a postural component (the center of mass must remain inside the support base). The model is based on an extension of the equilibrium point hypothesis that has been called Passive Motion Paradigm (PMP), modified in order to achieve terminal attractor features and allow the integration of multiple constraints. The model is a network with terminal attractor dynamics. By simulating it in various conditions it was possible to show that it exhibits many of the spatio-temporal features found in experimental data. In particular, the motion of the center of mass appears to be synchronized with the motion of the hand and with proportional amplitude. Moreover, the joint rotation patterns can be accounted for by a single functional degree of freedom, as shown by principal component analysis. It is also suggested that recent findings in motor imagery support the idea that the PMP network may represent the motor cognitive part of synergy formation, uncontaminated by the effect of execution.
Journal Article
Ablation of Focal Impulses and Rotational Sources: What Can Be Learned from Differing Procedural Outcomes?
by
Narayan, Sanjiv M.
,
Rodrigo, Miguel
,
Meckler, Gabriela L.
in
Ablation
,
Arrhythmias (J. Bunch
,
Cardiac arrhythmia
2017
Introduction
There is considerable interest in identifying potential drivers for human atrial fibrillation (AF), in order to improve therapy. Ablation via pulmonary vein isolation (PVI) is broadly used, yet is insufficient in many patients yet its outcomes are unimproved by adding extensive ablation of lines or complex electrogram sites, particularly in patients with persistent AF.
Novelty
Rotational and focal sources for AF represent novel mechanistic and therapeutic targets, often remote from the PVs and proven to drive AF in many studies. This chapter discusses this issue.
Aspects of Clinical Relevance
AF sources can now routinely be identified clinically by many methods, yet discrepant results have been reported. AF drivers identified by Focal Impulse and Rotor Mapping (FIRM), the most widely applied method, are also seen in simultaneous optical maps of human atria and have now been detected by other mapping methods applied to the exact same signals. In proof-of-concept studies, ablation of drivers can terminate persistent AF and, in over a thousand patients reported thus far, yield favorable long-term outcomes versus PVI alone. Nevertheless, some centers show disappointing results. This review focuses on discrepant results, which may reflect challenging patients, operator unfamiliarity with basket catheter use, or the technical ablation of drivers, amongst other factors. We discuss challenges, potential solutions, and future directions for map-guided AF driver ablation including basket-data collection, interpreting AF maps, ablation guidance, and extent.
Conclusions
Mapping and ablation of AF drivers is a rapidly growing field which, with continued scientific discovery and procedural advances, offers a strong mechanistic foundation to improve patient-tailored ablation for complex arrhythmias.
Journal Article
Global Prevention And Control Of Type 2 Diabetes Will Require Paradigm Shifts In Policies Within And Among Countries
by
Mohan, Vishwanathan
,
Echouffo-Tcheugui, Justin B.
,
Narayan, K.M. Venkat
in
Blood pressure
,
Cardiovascular disease
,
Chronic illnesses
2012
Continued increases in the prevalence of and disproportionate health spending associated with type 2 diabetes argue for policies focused on preventing that condition and treating it appropriately, even as we strive to improve coordination of care for coexisting chronic diseases. This article argues that four policy paradigm shifts will be necessary to achieve that specific emphasis on type 2 diabetes: conceptually integrating primary and secondary prevention along a clinical continuum; recognizing the central importance of early detection of prediabetes and undiagnosed diabetes in implementing cost-effective prevention and control; integrating community and clinical expertise, and resources, within organized and affordable service delivery systems; and sharing and adopting evidence-based policies at the global level. [PUBLICATION ABSTRACT]
Journal Article
Embodied Language Learning and Cognitive Bootstrapping: Methods and Design Principles
by
Förster, Frank
,
Lehmann, Hagen
,
Nehaniv, Chrystopher L.
in
Children & youth
,
Cognition & reasoning
,
Experiments
2016
Co-development of action, conceptualization and social interaction mutually scaffold and support each other within a virtuous feedback cycle in the development of human language in children. Within this framework, the purpose of this article is to bring together diverse but complementary accounts of research methods that jointly contribute to our understanding of cognitive development and in particular, language acquisition in robots. Thus, we include research pertaining to developmental robotics, cognitive science, psychology, linguistics and neuroscience, as well as practical computer science and engineering. The different studies are not at this stage all connected into a cohesive whole; rather, they are presented to illuminate the need for multiple different approaches that complement each other in the pursuit of understanding cognitive development in robots. Extensive experiments involving the humanoid robot iCub are reported, while human learning relevant to developmental robotics has also contributed useful results.
Disparate approaches are brought together via common underlying design principles. Without claiming to model human language acquisition directly, we are nonetheless inspired by analogous development in humans and consequently, our investigations include the parallel co-development of action, conceptualization and social interaction. Though these different approaches need to ultimately be integrated into a coherent, unified body of knowledge, progress is currently also being made by pursuing individual methods.
Journal Article