Abstract not found

In this paper, we survey the work in robotic grasping related areas that has been done over the last two decades, with a bias toward the development of the theoretical framework and analytical results in this area. In addition we assess the state of the art in this area and outline some of the important open problems.

This paper describes our current research into nonprehensile palm manipulation. The term “palm ” refers to the use of the entire device surface during manipulation, as opposed to use of the fingertips alone.

Properties of the human embodiment -- sensorimotor apparatus and neurological structure -- participate directly in the growth and development of cognitive processes against enormous worst case complexity. It is our position that relationships between morphology and perception over time lead to increasingly comprehensive models that describe the agent's relationship to the world. We are applying insight derived from neuroscience, neurology, and developmental psychology to the design of advanced robot architectures. To investigate developmental processes, we have begun to approximate the human sensorimotor configuration and to engage sensory and motor subsystems in developmental sequences. Many such sequences have been documented in studies of infant development, so we intend to bootstrap cognitive structures in robots by emulating some of these growth processes that bear an essential resemblance to the human morphology. In this paper, we will show two related examples in which a humanoid robot determines the models and representations that govern its behavior. The first is a model that captures the dynamics of a haptic exploration of an object with a dextrous robot hand that supports skillful grasping. The second example constructs constellations of visual features to predict relative hand/object postures that lead reliably to haptic utility. The result is a rst step in a trajectory toward associative visual-haptic categories that bounds the incremental complexity of each stage of development.

In this paper, an attempt at summarizing the evolution and the state-of-the-art in the field of robot hands is made. In such exposition, a critical evaluation of what in the author's view are the leading ideas and emerging trends, is privileged with respect to exhaustiveness of citations. The survey is focused mainly on three types of functional requirements a machine hand can be assigned in an artificial system, namely, manipulative dexterity, grasp robustness, and human operability. A basic distinction is made between hands designed for mimicking the human anatomy and physiology, and hands designed to meet restricted, practical requirements. In the latter domain, arguments are presented in favor of a "minimalistic" attitude in the design of hands for practical applications, i.e., use the least number of actuators, the simplest set of sensors, etc., for a given task. To achieve this rather obvious engineering goal is a challenge to our community. The paper illustrates some of the ...

The GALILEO-system is a developmental state-of-the-art rigid body simulation tool with a strong bias to the simulation of unilateral contacts for virtual reality applications. On the one hand the system is aimed at closing the gap between the ‘paradigms of impulse-based simulation ’ and of ‘constraint-based simulation’. On the other hand the chosen simulation techniques enable a balancing of the trade-off between the real-time demands of virtual environments (i.e. 15-25 visualizations per second) and the degree of physical correctness of the simulation. The focus of this paper lies on the constraint-based simulation approach to threedimensional multibody systems including a scalable friction model. This is only one of the two main components of the GALILEO-software-module. A nonlinear complementarity problem (NCP) describes the equations of motion, the contact conditions of the objects and the Coulomb friction model. Further on we show, as an interesting evaluation example from the field of ‘classical mechanics’, the first rigid body simulation of the tippe-top. 1

Complementarity formulations are a promising approach for solving dynamic multi-rigid-body contact problems. Here, we address two aspects of simulating contact in a complementarity setting. First, we develop an explicit formulation of the differential equations governing contact points for bodies of general surface geometry. These equations may be used to integrate the contact position and to set up the basic dynamics equations. Second, we present an efficient method for handling frictionless planar contacts of arbitrary boundary shape. Throughout, we attempt to set up the problem as explicitly as possible, paying special attention to the way the contact geometry is related to the dynamics. 1 Introduction 1.1 Motivation The dynamic multi-rigid-body contact problem is concerned with predicting the accelerations and contact forces of several rigid bodies in contact. Work in a number of research areas, robotics and virtual reality (VR) especially, has led to strong recent interest in th...

Geometric uncertainty is unavoidable when programming robots for physical applications. We propose a stochastic framework for manipulation planning where plans are ranked on the basis of expected cost. That is, we express the desirability of states and actions with a cost function and describe uncertainty with probability distributions. We illustrate the approach with a new design for a programmable parts feeder, a mechanism that orients two-dimensional parts using a sequence of open-loop mechanical motions. We present a planning algorithm that accepts an n-sided polygonal part as input and, in time O(n²), generates a stochastically optimal plan for orienting the part.

Autonomous robot tasks involving contacts with the environment must be performed under active force control if the geometric uncertainties in the task models are too large to cope with by means of passive compliance only. In practice, task speci cation of force-controlled actions is closely linked to the Task Frame Formalism (TFF), also known as the compliance frame formalism. The TFF is a very intuitive and controller independent approach to model a motion constraint, and to specify the desired forces and motions compatible with this constraint. However, it has never been de ned clearly and unambiguously, and it cannot cope with all possible constrained motion tasks. This paper provides, for the rst time, a formal de nition of what makes up a TFF task speci cation. It gives also a synthesis of which tasks the TFF can cope with, and proposes a generic textual task speci- cation formalism. Finally, it describes an example constrained motion task that the TFF cannot handle. Keywords: c...

Pairs of bodies with regular rigid surfaces rolling onto each other in space form a nonholonomic system of a rather general type, posing several interesting control problems of which not much is known. The nonholonomy of such systems can be exploited in practical devices, which is very useful in robotic applications. In order to achieve all potential benefits, a deeper understanding of these types of systems and more practical algorithms for planning and controlling their motions are necessary. In this paper, we study the controllability aspect of this problem, giving a complete description of the reachable manifold for general pairs of bodies, and a constructive controllability algorithm for planning rolling motions for dexterous robot hands. Index Terms---Nonholonomic systems, nonlinear controllability theory, robotic manipulation. I. INTRODUCTION N ON-HOLONOMIC systems have been attracting much attention in control literature recently, due to both their relevance to practical ap...