348 research outputs found
A Robotic System for Learning Visually-Driven Grasp Planning (Dissertation Proposal)
We use findings in machine learning, developmental psychology, and neurophysiology to guide a robotic learning system\u27s level of representation both for actions and for percepts. Visually-driven grasping is chosen as the experimental task since it has general applicability and it has been extensively researched from several perspectives. An implementation of a robotic system with a gripper, compliant instrumented wrist, arm and vision is used to test these ideas. Several sensorimotor primitives (vision segmentation and manipulatory reflexes) are implemented in this system and may be thought of as the innate perceptual and motor abilities of the system.
Applying empirical learning techniques to real situations brings up such important issues as observation sparsity in high-dimensional spaces, arbitrary underlying functional forms of the reinforcement distribution and robustness to noise in exemplars. The well-established technique of non-parametric projection pursuit regression (PPR) is used to accomplish reinforcement learning by searching for projections of high-dimensional data sets that capture task invariants.
We also pursue the following problem: how can we use human expertise and insight into grasping to train a system to select both appropriate hand preshapes and approaches for a wide variety of objects, and then have it verify and refine its skills through trial and error. To accomplish this learning we propose a new class of Density Adaptive reinforcement learning algorithms. These algorithms use statistical tests to identify possibly interesting regions of the attribute space in which the dynamics of the task change. They automatically concentrate the building of high resolution descriptions of the reinforcement in those areas, and build low resolution representations in regions that are either not populated in the given task or are highly uniform in outcome.
Additionally, the use of any learning process generally implies failures along the way. Therefore, the mechanics of the untrained robotic system must be able to tolerate mistakes during learning and not damage itself. We address this by the use of an instrumented, compliant robot wrist that controls impact forces
TOWARDS THE GROUNDING OF ABSTRACT CATEGORIES IN COGNITIVE ROBOTS
The grounding of language in humanoid robots is a fundamental problem, especially
in social scenarios which involve the interaction of robots with human beings. Indeed,
natural language represents the most natural interface for humans to interact
and exchange information about concrete entities like KNIFE, HAMMER and abstract
concepts such as MAKE, USE. This research domain is very important not
only for the advances that it can produce in the design of human-robot communication
systems, but also for the implication that it can have on cognitive science.
Abstract words are used in daily conversations among people to describe events and
situations that occur in the environment. Many scholars have suggested that the
distinction between concrete and abstract words is a continuum according to which
all entities can be varied in their level of abstractness.
The work presented herein aimed to ground abstract concepts, similarly to concrete
ones, in perception and action systems. This permitted to investigate how different
behavioural and cognitive capabilities can be integrated in a humanoid robot in
order to bootstrap the development of higher-order skills such as the acquisition of
abstract words. To this end, three neuro-robotics models were implemented.
The first neuro-robotics experiment consisted in training a humanoid robot to perform
a set of motor primitives (e.g. PUSH, PULL, etc.) that hierarchically combined
led to the acquisition of higher-order words (e.g. ACCEPT, REJECT). The
implementation of this model, based on a feed-forward artificial neural networks,
permitted the assessment of the training methodology adopted for the grounding of
language in humanoid robots.
In the second experiment, the architecture used for carrying out the first study
was reimplemented employing recurrent artificial neural networks that enabled the
temporal specification of the action primitives to be executed by the robot. This
permitted to increase the combinations of actions that can be taught to the robot
for the generation of more complex movements.
For the third experiment, a model based on recurrent neural networks that integrated
multi-modal inputs (i.e. language, vision and proprioception) was implemented for
the grounding of abstract action words (e.g. USE, MAKE). Abstract representations
of actions ("one-hot" encoding) used in the other two experiments, were replaced
with the joints values recorded from the iCub robot sensors.
Experimental results showed that motor primitives have different activation patterns
according to the action's sequence in which they are embedded. Furthermore, the
performed simulations suggested that the acquisition of concepts related to abstract
action words requires the reactivation of similar internal representations activated
during the acquisition of the basic concepts, directly grounded in perceptual and
sensorimotor knowledge, contained in the hierarchical structure of the words used
to ground the abstract action words.This study was financed by the EU project RobotDoC (235065) from the Seventh
Framework Programme (FP7), Marie Curie Actions Initial Training Network
A survey of robot manipulation in contact
In this survey, we present the current status on robots performing manipulation tasks that require varying contact with the environment, such that the robot must either implicitly or explicitly control the contact force with the environment to complete the task. Robots can perform more and more manipulation tasks that are still done by humans, and there is a growing number of publications on the topics of (1) performing tasks that always require contact and (2) mitigating uncertainty by leveraging the environment in tasks that, under perfect information, could be performed without contact. The recent trends have seen robots perform tasks earlier left for humans, such as massage, and in the classical tasks, such as peg-in-hole, there is a more efficient generalization to other similar tasks, better error tolerance, and faster planning or learning of the tasks. Thus, in this survey we cover the current stage of robots performing such tasks, starting from surveying all the different in-contact tasks robots can perform, observing how these tasks are controlled and represented, and finally presenting the learning and planning of the skills required to complete these tasks
Integrating verbal and nonverbal communication in a dynamic neural field architecture for human–robot interaction
How do humans coordinate their intentions, goals and motor behaviors when performing joint action tasks? Recent experimental evidence suggests that resonance processes in the observer’s motor system are crucially involved in our ability to understand actions of others’, to infer their goals and even to comprehend their action-related language. In this paper, we present a control architecture for human–robot collaboration that exploits this close perception-action linkage as a means to achieve more natural and efficient communication grounded in sensorimotor experiences. The architecture is formalized by a coupled system of dynamic neural fields representing a distributed network of neural populations that encode in their activation patterns goals, actions and shared task knowledge. We validate the verbal and nonverbal communication skills of the robot in a joint assembly task in which the human–robot team has to construct toy objects from their components. The experiments focus on the robot’s capacity to anticipate the user’s needs and to detect and communicate unexpected events that may occur during joint task execution.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa POCI/V.5/A0119/2005 and CONC-REEQ/17/2001European Commission through the project JAST (IP-003747
M-EMBER: Tackling Long-Horizon Mobile Manipulation via Factorized Domain Transfer
In this paper, we propose a method to create visuomotor mobile manipulation
solutions for long-horizon activities. We propose to leverage the recent
advances in simulation to train visual solutions for mobile manipulation. While
previous works have shown success applying this procedure to autonomous visual
navigation and stationary manipulation, applying it to long-horizon visuomotor
mobile manipulation is still an open challenge that demands both perceptual and
compositional generalization of multiple skills. In this work, we develop
Mobile-EMBER, or M-EMBER, a factorized method that decomposes a long-horizon
mobile manipulation activity into a repertoire of primitive visual skills,
reinforcement-learns each skill, and composes these skills to a long-horizon
mobile manipulation activity. On a mobile manipulation robot, we find that
M-EMBER completes a long-horizon mobile manipulation activity,
cleaning_kitchen, achieving a 53% success rate. This requires successfully
planning and executing five factorized, learned visual skills
GPU Computing for Cognitive Robotics
This thesis presents the first investigation of the impact of GPU
computing on cognitive robotics by providing a series of novel experiments in
the area of action and language acquisition in humanoid robots and computer
vision. Cognitive robotics is concerned with endowing robots with high-level
cognitive capabilities to enable the achievement of complex goals in complex
environments. Reaching the ultimate goal of developing cognitive robots will
require tremendous amounts of computational power, which was until
recently provided mostly by standard CPU processors. CPU cores are
optimised for serial code execution at the expense of parallel execution, which
renders them relatively inefficient when it comes to high-performance
computing applications. The ever-increasing market demand for
high-performance, real-time 3D graphics has evolved the GPU into a highly
parallel, multithreaded, many-core processor extraordinary computational
power and very high memory bandwidth. These vast computational resources
of modern GPUs can now be used by the most of the cognitive robotics models
as they tend to be inherently parallel. Various interesting and insightful
cognitive models were developed and addressed important scientific questions
concerning action-language acquisition and computer vision. While they have
provided us with important scientific insights, their complexity and
application has not improved much over the last years. The experimental
tasks as well as the scale of these models are often minimised to avoid
excessive training times that grow exponentially with the number of neurons
and the training data. This impedes further progress and development of
complex neurocontrollers that would be able to take the cognitive robotics
research a step closer to reaching the ultimate goal of creating intelligent
machines. This thesis presents several cases where the application of the GPU
computing on cognitive robotics algorithms resulted in the development of
large-scale neurocontrollers of previously unseen complexity enabling the
conducting of the novel experiments described herein.European Commission Seventh Framework
Programm
Review of the techniques used in motor‐cognitive human‐robot skill transfer
Abstract A conventional robot programming method extensively limits the reusability of skills in the developmental aspect. Engineers programme a robot in a targeted manner for the realisation of predefined skills. The low reusability of general‐purpose robot skills is mainly reflected in inability in novel and complex scenarios. Skill transfer aims to transfer human skills to general‐purpose manipulators or mobile robots to replicate human‐like behaviours. Skill transfer methods that are commonly used at present, such as learning from demonstrated (LfD) or imitation learning, endow the robot with the expert's low‐level motor and high‐level decision‐making ability, so that skills can be reproduced and generalised according to perceived context. The improvement of robot cognition usually relates to an improvement in the autonomous high‐level decision‐making ability. Based on the idea of establishing a generic or specialised robot skill library, robots are expected to autonomously reason about the needs for using skills and plan compound movements according to sensory input. In recent years, in this area, many successful studies have demonstrated their effectiveness. Herein, a detailed review is provided on the transferring techniques of skills, applications, advancements, and limitations, especially in the LfD. Future research directions are also suggested
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