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The current research trends of object grasping can be summarized as caging grasping and force closure grasping. The motivation of this paper is to combine the advantage of caging grasping and force closure grasping to enable under-actuated grippers like the Lacquey gripper and the parallel grippers like the PR2 gripper to quickly grasp the flat unknown objects. Inspired by the idea that caging grasping...
Climbing robots are widely used to inspect smooth walls, such as glass curtain walls and ceramic tile surfaces. However, a good adsorption method for inspecting a cliffface and dusty high-altitude buildings with small-amplitude vibration has not been found. In this study, a new adsorption method using grasping claw grippers to adhere to rough walls is proposed and applied. A mechanical model for the...
How should a robot direct active vision so as to ensure reliable grasping? We answer this question for the case of dexterous grasping of unfamiliar objects. By dexterous grasping we simply mean grasping by any hand with more than two fingers, such that the robot has some choice about where to place each finger. Such grasps typically fail in one of two ways, either unmodeled objects in the scene cause...
Safe and robust grasping of unknown objects is a major challenge in robotics, which has no general solution yet. A promising approach relies on haptic exploration, where active optimization strategies can be employed to reduce the number of exploration trials. One critical problem is that certain optimal grasps discoverd by the optimization procedure may be very sensitive to small deviations of the...
Underactuated and synergy-driven hands are gaining attention in the grasping community mainly due to their simple kinematics, intrinsic compliance and versatility for grasping objects even in non structured scenarios. The evaluation of the grasping capabilities of such hands is a challenging task. This paper revisits some traditional quality measures developed for multi-fingered, fully actuated hands,...
This paper presents a novel design of a compact and light-weight robotic hand for a social humanoid robot. The proposed system is able to perform common hand gestures and self-adaptable grasps by mixing under-actuated and self-adaptable hand kinematics in a unique design. The hand answers the need for precise finger postures and sensor-less force feedback during gestures and for finger adaptation...
We propose a method to induce a realistic two-hand manipulation of virtual objects by representing their reactions to multiple contacts of hands and fingers in a unified way. One of the key problems in achieving physics-based virtual interaction is that there is no accurate haptic feedback to the user's hands and fingers, which must introduce a mismatch between the real hands and their virtual counterparts...
This paper presents an algorithm to compute precision grasps for bulky objects using two anthropomorphic hands. We use objects modeled as point clouds obtained from a sensor camera or from a CAD model. We process the point clouds dividing them into two set of slices, one for each hand, where we look for sets of triplets of points. Each triplet must accomplish some physical conditions based on the...
This paper describes a new task-oriented grasping method to reorient a rigid object to its nominal pose, which is defined as the configuration that it needs to be grasped from, in order to successfully execute a particular manipulation task. Our method combines two key insights: (1) a visual 6 Degree-of-Freedom (DoF) pose estimation technique based on 2D-3D point correspondences is used to estimate...
The concept of “affordance” has typically represented the relationship between human perceivers and their environment. Affordance perception, representation, and inference are central to commonsense reasoning, tool-use and creative problem-solving in artificial agents. Existing approaches to representing affordances have focused on its physical aspects, relying on either static ontologies or statistical...
In almost all tasks performed by a human being implicit handling of objects, specifically grasp objects, is paramount in most tasks and is an area of robotic research. This paper presents the combination of two programming by demonstration techniques to improve the quality of grasp objects. The two techniques are the Gaussian mixture model and task parameterized Gaussian mixture model. One simulated...
This paper proposes a novel dexterous robotic finger with sensing parallel and self-adaptive grasp, called S-PASA finger, which can perform parallel and self-adaptive hybrid grasping mode. The S-PASA finger consists of two phalanges, two joints, a four-link mechanism with a composite flexible link, one spring, four sensors, a control module, a drive module, and two servo motors. The S-PASA finger...
A traditional robot finger can achieve either pinching or enveloping grasp instead of both functions. It is necessary to design a finger combining with both functions. This paper designs a novel parallel and self-adaptive underactuated robotic finger with belt and cam-link mechanism, named as PASA-BCL finger, which mainly consists of a motor, a cam-link part, two pulleys, a spring, a mechanical limit...
This paper describes the design and initial prototype of a thumb curling exoskeleton for movement therapy. This add-on device for the Finger INdividuating Grasp Exercise Robot (FINGER) guides the thumb through a single-degree-of-freedom naturalistic grasping motion. This motion complements the grasping motions of the index and middle fingers provided by FINGER. The kinematic design and mechanism synthesis...
This paper developed a self-adaptive robotic hand with novel flexible fingers of multiple passive joints, called MPJ hand, whose main mechanism is based on the linkage-style parallel and self-adaptive finger in SARAH Hand, can perform parallel pinching grasp and self-adaptive encompassing grasping modes with relatively even force distribution. A MPJ hand is developed with three MPJ fingers and 45...
Stably grasping objects for a specific task is a hot research topic in robotics due to multiple degrees of freedom of hand kinematics, incomplete visual sensing of objects, and various shapes of objects. This paper proposes an effective grasp planning method by integrating the crucial grasp cues (positions and orientations of thumb fingertips and the wrist) from human experience. This approach greatly...
Tofu shows the following compression behavior. First, the behavior is non-linear; subsequently, the behavior becomes elastic/linear, followed by yielding and fracture. A linear behavior indicates that there is no fracture, but further increase of compression can cause yielding or fracture. The compression in the region of linear behavior then can be regarded as maximum. With this in mind, this paper...
This paper proposes a novel method for randomized bin-picking based on learning. When a two-fingered gripper tries to pick an object from the pile, a finger often contacts a neighboring object. Even if a finger contacts a neighboring object, the target object will be successfully picked depending on the configuration of neighboring objects. In our proposed method, we use the visual information on...
The paper focuses on the grasp requirements derived from the voluntary and involuntary physical interactions in instrument manipulations. The manipulation-oriented grasp requirements include interactive wrench requirements and motion requirements that are required to accomplish a manipulation task. The manipulation-oriented grasp requirements are directly associated with the functionality of the instrument...
The past decade has seen great progress in the development of adaptive, low-complexity, underactuated robot hands. An advantage of these hands is that they use under-constrained mechanisms and compliance, which facilitate grasping even under significant object pose uncertainties. However, for many minimal contact grasps such as precision fingertip grasps, these hands tend to move the object after...
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