Machine Systems for Exploration and Manipulation: A Conceptual Framework and Method of Evaluation

A conceptual approach to describing and evaluating problem-solving by robotic systems is offered. One particular problem of importance to the field of robotics, disassembly, is considered. A general description is provided of an effector system equipped with sensors that interacts with objects for purposes of disassembly and that learns as a result. The system\u27s approach is bottom up, in that it has no a priori knowledge about object categories. It does, however, have pre-existing methods and strategies for exploration and manipulation. The sensors assumed to be present are vision, proximity, tactile, position, force, and thermal. The system\u27s capabilities are described with respect to two phases: object exploration and manipulation. Exploration takes the form of executing exploratory procedures, algorithms for determining the substance, structure, and mechanical properties of objects. Manipulation involves manipulatory operators, defined by the type of motion, nature of the end-effector configuration, and precise parameterization. The relation of the hypothesized system to existing implementations is described, and a means of evaluating it is also proposed

Object grasping and manipulation in capuchin monkeys (genera Cebus and Sapajus)

The abilities to perform skilled hand movements and to manipulate objects dexterously are landmarks in the evolution of primates. The study of how primates use their hands to grasp and manipulate objects in accordance with their needs sheds light on how these species are physically and mentally equipped to deal with the problems they encounter in their daily life. We report data on capuchin monkeys, highly manipulative platyrrhine species that usually spend a great deal of time in active manipulation to search for food and to prepare it for ingestion. Our aim is to provide an overview of current knowledge on the ability of capuchins to grasp and manipulate objects, with a special focus on how these species express their cognitive potential through manual behaviour. Data on the ability of capuchins to move their hands and on the neural correlates sustaining their actions are reported, as are findings on the manipulative ability of capuchins to anticipate future actions and to relate objects to other objects and substrates. The manual behaviour of capuchins is considered in different domains, such as motor planning, extractive foraging and tool use, in both captive and natural settings. Anatomofunctional and behavioural similarities to and differences from other haplorrhine species regarding manual dexterity are also discussed

Robot Active Touch Exploration: Constraints and Strategies

We investigate the problem of using active touch ("haptic") exploration to recognize a 3D object taken from a known set of models. "That is new is that we combine two approaches: (1) using geometric constraints between components to eliminate interpretations, and interpretation tree methods for choosing the best active sensing move; (2) exploratory moves made by tracing continually along the surface of the object (and not through free space). We restrict ourselves to polyhedral, and give a set of geometric constraints tailored for matching components acquired from haptic exploration against components in the models. We present a new constraint using pairs of line segments. We then give a set of active sensing moves, each with an associated cost measure, and our strategies for choosing the next move

Multimodal Hierarchical Dirichlet Process-based Active Perception

In this paper, we propose an active perception method for recognizing object categories based on the multimodal hierarchical Dirichlet process (MHDP). The MHDP enables a robot to form object categories using multimodal information, e.g., visual, auditory, and haptic information, which can be observed by performing actions on an object. However, performing many actions on a target object requires a long time. In a real-time scenario, i.e., when the time is limited, the robot has to determine the set of actions that is most effective for recognizing a target object. We propose an MHDP-based active perception method that uses the information gain (IG) maximization criterion and lazy greedy algorithm. We show that the IG maximization criterion is optimal in the sense that the criterion is equivalent to a minimization of the expected Kullback--Leibler divergence between a final recognition state and the recognition state after the next set of actions. However, a straightforward calculation of IG is practically impossible. Therefore, we derive an efficient Monte Carlo approximation method for IG by making use of a property of the MHDP. We also show that the IG has submodular and non-decreasing properties as a set function because of the structure of the graphical model of the MHDP. Therefore, the IG maximization problem is reduced to a submodular maximization problem. This means that greedy and lazy greedy algorithms are effective and have a theoretical justification for their performance. We conducted an experiment using an upper-torso humanoid robot and a second one using synthetic data. The experimental results show that the method enables the robot to select a set of actions that allow it to recognize target objects quickly and accurately. The results support our theoretical outcomes.Comment: submitte

HEAP: A Sensory Driven Distributed Manipulation System

We address the problems of locating, grasping, and removing one or more unknown objects from a given area. In order to accomplish the task we use HEAP, a system of coordinating the motions of the hand and arm. HEAP also includes a laser range finer, mounted at the end of a PUMA 560, allowing the system to obtain multiple views of the workspace. We obtain volumetric information of the objects we locate by fitting superquadric surfaces on the raw range data. The volumetric information is used to ascertain the best hand configuration to enclose and constrain the object stably. The Penn Hand used to grasp the object, is fitted with 14 tactile sensors to determine the contact area and the normal components of the grasping forces. In addition the hand is used as a sensor to avoid any undesired collisions. The objective in grasping the objects is not to impart arbitrary forces on the object, but instead to be able to grasp a variety of objects using a simple grasping scheme assisted with a volumetric description and force and touch sensing

Tactile-dependant corticomotor facilitation is influenced by discrimination performance in seniors

<p>Abstract</p> <p>Background</p> <p>Active contraction leads to facilitation of motor responses evoked by transcranial magnetic stimulation (TMS). In small hand muscles, motor facilitation is known to be also influenced by the nature of the task. Recently, we showed that corticomotor facilitation was selectively enhanced when young participants actively discriminated tactile symbols with the tip of their index or little finger. This tactile-dependant motor facilitation reflected, for the large part, attentional influences associated with performing tactile discrimination, since execution of a concomitant distraction task abolished facilitation. In the present report, we extend these observations to examine the influence of age on the ability to produce extra motor facilitation when the hand is used for sensory exploration.</p> <p>Methods</p> <p>Corticomotor excitability was tested in 16 healthy seniors (58-83 years) while they actively moved their right index finger over a surface under two task conditions. In the tactile discrimination (TD) condition, participants attended to the spatial location of two tactile symbols on the explored surface, while in the non discrimination (ND) condition, participants simply moved their finger over a blank surface. Changes in amplitude, in latency and in the silent period (SP) duration were measured from recordings of motor evoked potentials (MEP) in the right first dorsal interosseous muscle in response to TMS of the left motor cortex.</p> <p>Results</p> <p>Healthy seniors exhibited widely varying levels of performance with the TD task, older age being associated with lower accuracy and vice-versa. Large inter-individual variations were also observed in terms of tactile-specific corticomotor facilitation. Regrouping seniors into higher (n = 6) and lower performance groups (n = 10) revealed a significant task by performance interaction. This latter interaction reflected differences between higher and lower performance groups; tactile-related facilitation being observed mainly in the former group. Latency measurements and SP durations were not affected by task conditions.</p> <p>Conclusions</p> <p>The present findings provide further insights into the factors influencing task-dependant changes in corticomotor excitability in the context of aging. Our results, in particular, highlight the importance of adjusting task demands and controlling for attention when attempting to elicit task-specific motor facilitation in older persons engaged in fine manual actions. Such information could be critical in the future for planning interventions to re-educate or maintain hand function in the presence of neurological impairments.</p