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Most objects are composed of parts which have a semantic meaning. Ahandle can have many different shapes and can be present in quite different objects, but there is only one semantic meaning to a handle, which is "a part that is designed especially to be grasped by the hand". We introduce here a novel 3D algorithm named CPS for the decomposition of objects into their semantically meaningful...
This paper presents a numerical method to conceive and design the kinematic model of an anthropomorphic robotic hand used for gesturing and grasping. In literature, there are few numerical methods for the finger placement of human-inspired robotic hands. In particular, there are no numerical methods, for the thumb placement, that aim to improve the hand dexterity and grasping capabilities by keeping...
Reliable precision grasping is a pre-condition for manipulation tasks e.g. in assembly and packaging tasks. Especially for small and light objects robust grasping is extremely challenging since even slight errors in the object pose or dimensions lead to irreparable failures caused by unintended finger-object contacts. State of the art techniques address the problem of grasping in the presence of uncertainty...
This paper deals with the problem of determining independent contacts regions (ICRs) on 2D articulated objects, such that a finger contact in each region guarantees a force-closure (FC) immobilization, independently of the exact position of the finger. These regions allow a robust finger or fixture placement on the links of the articulated object, despite of possible errors in the position of the...
This paper addresses the problem of finding robot configurations to grasp assembly parts during a sequence of collaborative assembly operations. We formulate the search for such configurations as a constraint satisfaction problem (CSP). Collision constraints in an operation and transfer constraints between operations determine the sets of feasible robot configurations. We show that solving the connected...
While human-like series passive compliance has been used in previous robotic hand designs, little attention has been paid to parallel passive compliance due to the lack of understanding of its importance in grasping and manipulation. In this paper, we present a novel design of compliant finger inspired by biomechanical features and functionality of human hands. We develop a human-like compact joint...
Difficulties in automatic handling of many food materials are due to their softness and easy deformability by external forces. Excessive deformation of food materials damages their quality and must be avoided. Another difficulty in automatic food handling is the irregular shape and size of food materials, requiring robotic hands to adjust for differences in shapes and sizes. This study describes binding-based...
Grasping an object in a cluttered, unorganized environment is challenging because of unavoidable contacts and interactions between the robot and multiple immovable (static) and movable (dynamic) obstacles in the environment. Planning an approach trajectory for grasping in such situations can benefit from physics-based simulations that describe the dynamics of the interaction between the robot manipulator...
Functionality of a human hand can be augmented with extra robotic fingers attached to the forearm. These wearable extra fingers can work together with the human fingers and perform tasks that are usually difficult for a single hand. Such technology may benefit amputees and surviving stroke patients who are forced to live with only one functional arm. In this paper, we present a novel method, exploiting...
In this paper, the problem of a class of hyperredundant arms with continuum elements that performs the grasping function by coiling is discussed. This function is often met in the animal world as the elephant's trunk or octopus tentacle. First, the dynamic model in 3D-space is developed. The equations that describe the motion of the arm that carries a load by coiling are inferred. The stability of...
Capturing features of brainwaves (Electroencephalographic EEG activity), and brain patterns involved in grasping is not a trivial task. This is due to the complication of such patterns. In this context, this paper will be focusing on mechanisms of decoding and learned patterns of neural waves for robotic grasping applications. This is based on using c-mean clustering routines, as associated with PCA...
For biped pole-climbing robots (BiPCRs), footholds, indicating a sequence of discrete gripping points from the start to the goal, are necessary for travelling in trussed environments. Graspable region in each climbing cycle is the valuable priori knowledge for consideration of selecting specific grasping point. However, how to evaluate all the grasps within the graspable region so as to provide a...
This paper proposes an algorithm that estimates a reaction torque loading the grasping jaws of wire-actuated robotic forceps and compensates for subsequent wire elongation. The algorithm is constructed by the combination of the Reaction Force Observer (RFOB) and an optimization problem based on a gradient descent method. The conventional RFOB is used to estimate an external torque that includes not...
Dexterous manipulation by multi-fingered robotics hands has been a research topic for more than thirty years. However, forming grasping closure and determination of fingertips forces has always been an issue due to related complexity. Will a robotic hand grasping be enhanced via learning from human grasping? There have been a number of attempts for that. This article is presenting a different approach,...
In this paper, the estimation of the grasping torque of robotic forceps without the use of a force/torque sensor is discussed. To estimate the grasping torque when the robotic forceps driven by a rotary motor with a reduction gear grasps an object, a novel robust reaction torque observer is proposed. The robust reaction torque observer is developed according to the following steps. First, cancellation...
This paper presents a minimalist, four-finger hand comprised of two pairs of tendon-driven, underactuated fingers decoupled by an independent, central, rotating axis. This mechanical configuration allows for finger-gaiting while also retaining the passive adaptability and other capabilities of the underactuated finger pairs. As a result, the hand, requiring only four actuators, is capable of a unique...
In this work, a multi-sensor controller to open recipients with screwed caps is presented. A humanoid torso is used to perform the task, first grabbing and holding the target object with one hand and then removing the cap with the other hand. The approach consists of a global controller composed of several modules: object segmentation, grasp synthesis, grasp execution and cap unscrew controller. The...
Despite some prematurely optimistic claims, the ability of robots to grasp general objects in unstructured environments still remains far behind that of humans. This is not solely caused by differences in the mechanics of hands: indeed, we show that human use of a simple robot hand (the Pisa/IIT SoftHand) can afford capabilities that are comparable to natural grasping. It is through the observation...
In this research, we demonstrated dexterous manipulation of sheet-like elastic objects, namely, playing cards, using a high-speed robot system. In particular, our goal was to achieve card throwing and card shooting towards a target object by using a high-speed multifingered robot hand and visual feedback based on a vision system. We discuss card grasping in the initial state by analyzing the motion...
This paper focuses on improving performance with practice for tasks that are difficult to model or plan, such as pouring (manipulating a liquid or granular material such as sugar). We are also interested in tasks that involve the possible use of many skills, such as pouring by tipping, shaking, and tapping. Although our ultimate goal is to learn and optimize skills automatically from demonstration...
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