Efficient models for grasp planning with a multi-fingered hand

Abstract

This paper presents a simple grasp planning method for a multifingered hand. Its purpose is to compute a context-independent and dense set or list of grasps, instead of just a small set of grasps regarded as optimal with respect to a given criterion. By context-independent, we mean that only the robot hand and the object to grasp are considered. The environment and the position of the robot base with respect to the object are considered in a further stage. Such a dense set can be computed offline and then used to let the robot quickly choose a grasp adapted to a specific situation. This can be useful for manipulation planning of pick-and-place tasks. Another application is human-robot interaction when the human and robot have to hand over objects to each other. If human and robot have to work together with a predefined set of objects, grasp lists can be employed to allow a fast interaction. The proposed method uses a uniform sampling of the possible hand approaches. As this leads to many finger inverse kinematics tests, hierarchical data structures are employed to reduce the computation times. The data structures allow a fast determination of the points where the fingers can realize a contact with the object surface. The grasps are ranked according to a grasp quality criterion so that the robot will first parse the list from best to worse quality grasps, until it finds a grasp that is valid for a particular situation.

Ingredients and a Framework of Dexterous Manipulation Skills for Robots in Human Centered Environment and HRI

“…Dedicated modules are used to realize different components of Fig. 2: a multi-fingered hands grasp planner [17], to compute a set of grasps, with a stability score, for objects of different shapes (see Fig. 3); Mightability Analysis (what an agent might be able to see and reach, without and with some efforts) [8], for visuo-spatial perspective taking based candidate placement position extraction; Ref.…”

Grasping bulky objects with two anthropomorphic hands

“…Many of this approaches use optimization methods to find valid hand configurations [12], [13], [14], [15], [16], or discretize the workspace of the hands in order to simplify the search of suitable poses of the fingers on the object surface [17], [18], [19], or select the best grasp using a set of grasp quality metrics [20], [21].…”

“…Then, the distances between the fingers are computed and the condition in eq. (3) is checked (line [19][20][21][22]. If the distances accomplishes such condition, the area of the triangle A, formed by the three points, and its quality Q are computed (lines 23-24).…”

A Reactive Controller Based on Online Trajectory Generation for Object Manipulation

“…The grasp position, the contact points and the final trajectory are planned by the grasp planner. More details on the grasp planner are given in [3] and [25]. When the object moves, the object frame F o and the path of the trajectory moves also.…”