4,477 research outputs found
Sim-to-Real Transfer of Robotic Control with Dynamics Randomization
Simulations are attractive environments for training agents as they provide
an abundant source of data and alleviate certain safety concerns during the
training process. But the behaviours developed by agents in simulation are
often specific to the characteristics of the simulator. Due to modeling error,
strategies that are successful in simulation may not transfer to their real
world counterparts. In this paper, we demonstrate a simple method to bridge
this "reality gap". By randomizing the dynamics of the simulator during
training, we are able to develop policies that are capable of adapting to very
different dynamics, including ones that differ significantly from the dynamics
on which the policies were trained. This adaptivity enables the policies to
generalize to the dynamics of the real world without any training on the
physical system. Our approach is demonstrated on an object pushing task using a
robotic arm. Despite being trained exclusively in simulation, our policies are
able to maintain a similar level of performance when deployed on a real robot,
reliably moving an object to a desired location from random initial
configurations. We explore the impact of various design decisions and show that
the resulting policies are robust to significant calibration error
Progress in Behavioral Game Theory
Is game theory meant to describe actual choices by people and institutions or
not? It is remarkable how much game theory has been done while largely
ignoring this question. The seminal book by von Neumann and Morgenstern,
The Theory of Games and Economic Behavior, was clearly about how rational players
would play against others they knew were rational. In more recent work, game
theorists are not always explicit about what they aim to describe or advise. At one
extreme, highly mathematical analyses have proposed rationality requirements that
people and firms are probably not smart enough to satisfy in everyday decisions. At
the other extreme, adaptive and evolutionary approaches use very simple models-mostly
developed to describe nonhuman animals-in which players may not realize
they are playing a game at all. When game theory does aim to describe behavior,
it often proceeds with a disturbingly low ratio of careful observation to theorizing
Inside the brain of an elite athlete: The neural processes that support high achievement in sports
Events like the World Championships in athletics and the Olympic Games raise the public profile of competitive sports. They may also leave us wondering what sets the competitors in these events apart from those of us who simply watch. Here we attempt to link neural and cognitive processes that have been found to be important for elite performance with computational and physiological theories inspired by much simpler laboratory tasks. In this way we hope to inspire neuroscientists to consider how their basic research might help to explain sporting skill at the highest levels of performance
A Review of Control Strategies in Closed-Loop Neuroprosthetic Systems
It has been widely recognized that closed-loop neuroprosthetic systems achieve more favourable outcomes for users then equivalent open-loop devices. Improved performance of tasks, better usability and greater embodiment have all been reported in systems utilizing some form of feedback. However the interdisciplinary work on neuroprosthetic systems can lead to miscommunication due to similarities in well established nomenclature in different fields. Here we present a review of control strategies in existing experimental, investigational and clinical neuroprosthetic systems in order to establish a baseline and promote a common understanding of different feedback modes and closed loop controllers. The first section provides a brief discussion of feedback control and control theory. The second section reviews the control strategies of recent Brain Machine Interfaces, neuromodulatory implants, neuroprosthetic systems and assistive neurorobotic devices. The final section examines the different approaches to feedback in current neuroprosthetic and neurorobotic systems
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
Motivation: A selected bibliography
A bibliography is presented of books, periodicals, and documents concerning managerial motivation
Remembering as a mental action
Many philosophers consider that memory is just a passive information retention and retrieval capacity. Some information and experiences are encoded, stored, and subsequently retrieved in a passive way, without any control or intervention on the subject’s part. In this paper, we will defend an active account of memory according to which remembering is a mental action and not merely a passive mental event. According to the reconstructive account, memory is an imaginative reconstruction of past experience. A key feature of the reconstructive account is that given the imperfect character of memory outputs, some kind of control is needed. Metacognition is the control of mental processes and dispositions. Drawing from recent work on the normativity of automaticity and automatic control, we distinguish two kinds of metacognitive control: top-down, reflective control, on the one hand, and automatic, intuitive, feeling-based control on the other. Thus, we propose that whenever the mental process of remembering is controlled by means of intuitive or feeling-based metacognitive processes, it is an action
Rearrangement with Nonprehensile Manipulation Using Deep Reinforcement Learning
Rearranging objects on a tabletop surface by means of nonprehensile
manipulation is a task which requires skillful interaction with the physical
world. Usually, this is achieved by precisely modeling physical properties of
the objects, robot, and the environment for explicit planning. In contrast, as
explicitly modeling the physical environment is not always feasible and
involves various uncertainties, we learn a nonprehensile rearrangement strategy
with deep reinforcement learning based on only visual feedback. For this, we
model the task with rewards and train a deep Q-network. Our potential
field-based heuristic exploration strategy reduces the amount of collisions
which lead to suboptimal outcomes and we actively balance the training set to
avoid bias towards poor examples. Our training process leads to quicker
learning and better performance on the task as compared to uniform exploration
and standard experience replay. We demonstrate empirical evidence from
simulation that our method leads to a success rate of 85%, show that our system
can cope with sudden changes of the environment, and compare our performance
with human level performance.Comment: 2018 International Conference on Robotics and Automatio
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