Analysis and design for changing finger posture in a robotic hand

Optimal Grip Points with Human Hand

The aim of this work was to determine how an object of given shape should be grasped to maximize the grasping capacity of the human hand. To do that the model searches the optimal grip points on the object with the aim of maximizing the weight of the object lifted without slipping. The model solves both the equilibrium of the grasped object and the biomechanical constraints of the human hand, such as the stress limit of each muscle. To give some examples, grasps of three-dimensional (3D) objects of different shape and size were optimized. The results of the simulations done also allowed the identification of the parameters that further influence human grasping. Moreover, trials were done to prove the results given by the computational model.

Leap Motion Device Used to Control a Real Anthropomorphic Gripper

This paper presents for the first time the use of the Leap Motion device to control an anthropomorphic gripper with five fingers. First, a description of the Leap Motion device is presented, highlighting its main functional characteristics, followed by testing of its use for capturing the movements of a human hand's fingers in different configurations. Next, the HandCommander soft module and the Interface Controller application are described. The HandCommander is a software module created to facilitate interaction between a human hand and the GraspIT virtual environment, and the Interface Controller application is required to send motion data to the virtual environment and to test the communication protocol. For the test, a prototype of an anthropomorphic gripper with five fingers was made, including a proper hardware system of command and control, which is briefly presented in this paper. Following the creation of the prototype, the command system performance test was conducted under real conditions, evaluating the recognition efficiency of the objects to be gripped and the efficiency of the command and control strategies for the gripping process. The gripping test is exemplified by the gripping of an object, such as a screw spanner. It was found that the command system, both in terms of capturing human hand gestures with the Leap Motion device and effective object gripping, is operational. Suggestive figures are presented as examples.

Performance Comparison Between FEDERICA Hand and LARM Hand

This paper describes two robotic hands that have been developed at University Federico II of Naples and at the University of Cassino. FEDERICA Hand and LARM Hand are described in terms of design and operational features. In particular, careful attention is paid to the differences between the above-mentioned hands in terms of transmission systems. FEDERICA Hand uses tendons and pulleys to drive phalanxes, while LARM Hand uses cross four-bar linkages. Results of experimental tests are reported to show how key design issues affect each robotic hand's performance.

KINEMATIC ANALYSIS AND PROTOTYPE OF A METAMORPHIC ANTHROPOMORPHIC HAND WITH A RECONFIGURABLE PALM

A novel metamorphic anthropomorphic hand is for the first time introduced in this paper. This robotic hand has a reconfigurable palm that generates changeable topology and augments dexterity and versatility of the hand. Structure design of the robotic hand is presented and based on mechanism decomposition kinematics of the metamorphic anthropomorphic hand is characterized with closed-form solutions leading to the workspace investigation of the robotic hand. With characteristic matrix equation, twisting motion of the metamorphic robotic hand is investigated to reveal both dexterity and manipulability of the metamorphic hand. Through a prototype, grasping and prehension of the robotic hand are tested to illustrate characteristics of the new metamorphic anthropomorphic hand.