Sergio Savino

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 hands performance.

An Underactuated Multi-finger Grasping Device

In this paper, a mechanical model for an underactuated multi-finger grasping device is presented. The device has single-tendon, three-phalanx fingers, all moved by only one actuator. By means of the model, both the kinematic and dynamical behaviour of the finger itself can be studied. The finger is part of a more complex mechanical system that consists of a four-finger grasping device for robots or a five-finger human hand prosthesis. Some results of both the kinematic and dynamical behaviour are also presented.

A study of a robotic hand with tendon driven fingers

In the present paper, a model of an underactuated robotic hand with tendon driven fingers is proposed. The aim of the project was to study the feasibility of building a mechanical hand with four or five fingers, the movement of which is achieved using a single linear actuator. The mechanism was first modelled in order to study the possible improvement in the ability of a “robotic hand” powered with a single actuator in regard to grasping objects with complex shapes and also in achieving a strong grip on objects. Next, a model of the finger was studied in order to optimize of its parameters. Finally, a five-fingered robotic hand was modelled for potential application as a human hand prosthesis. Our studies on the dynamic and kinematic behaviour of a single finger mechanism permitted us to make the first prototypes of the mechanism. In addition to modelling studies, we also present a prototype of the modelled robotic hand that was developed in order to optimize functionality and simplicity of construction.

Mechanical model of a single tendon finger

The mechanical model of a single tendon three phalanxes finger is presented. By means of the model both kinematic and dynamical behavior of the finger itself can be studied. This finger is a part of a more complex mechanical system that consists in a four finger grasping device for robots or in a five finger human hand prosthesis. A first prototype has been realized in our department in order to verify the real behavior of the model. Some results of both kinematic and dynamical behavior are presented.

An underactuated mechanical hand: A first prototype

In the present paper a model of an underactuated tendon driven mechanical hand is proposed. The aim of the activity was to study the possibility of realization of a mechanical hand five fingers, the movement of which is realized by the use of one only actuator. The mechanism is conceived as an hand prosthesis. The main particularity of the device essentially consist in that it is based on an adaptive scheme. In this way it is possible to obtain that the three phalanxes of each of the fingers adapt their rotation to the grasped object shape. This will be obtained by non-extendible tendons. So each finger will grasp the object surface independently on the configuration of the finger itself and independently on the configuration of the other fingers.

Performance of Greek–Roman Artillery

Abstract The main throwing machines invented and used by the Greeks and adopted, more widely, by Roman armies are examined. The kinematics and dynamics of both light and heavy Greek–Roman artillery are used in order to accurately assess its performance. Thus, a better understanding is obtained of the tactics and strategies of the legions of the Roman Empire as well as the reasons for some brilliant campaigns. Reconstructions of a repeating catapult, considered to be the ancestor of the modern machine gun, are also presented. The development of the mechanical design of such machines is discussed and pictorial reconstructions proposed.

Influence of the Tendon Design on the Behavior of an Under-Actuated Finger

An investigation on the influence of the design parameters of the tendon system on the behavior of an under-actuated finger is presented. The study was carried on by simulations with Working Model 2D™ and by an experimental apparatus.

Gripping Analysis of an Underactuated Finger

The paper presents a theoretical study about the gripping of an underactuated tendon driver finger. The studies presented in the paper have been performed to analyse the capability of the proposed device to apply forces on the grasped object and to analyse the behaviour of the contact actions during the grasping. The analysis of two models is reported and the results of simulations are shown. The obtained results show a good efficiency of the designed finger.

3D Object Reconstruction Using a Robot Arm

A technique for a vision application is proposed by means of which it is possible to obtain the three dimensional reconstruction of surfaces and objects. This technique uses a number of images from a single camera that is moved around the object by a robot arm. In this way the calibration of the video system is no more necessary because the robot kinematics is known. The images are processed by an algorithm that has been developed starting from our previous investigations on computer vision applied to robotics. The reconstruction of the images can be easily used to reproduce the object itself by means of tools installed on a robot arm. Some examples are given.

An application of vision systems to the path planning of industrial robots

In this paper the early results on the possibility to use a video system for the robots trajectories planning is presented. By means of this application it is possible to plan the trajectories by a PC monitor, just clicking with the mouse on the monitor. In order to obtain a three dimensional vision a couple of cameras has been used. A software was developed that by means of each couple of frames make possible to select a desired point in the work space, obtaining three cartesian coordinates. These last are given to the control system and recorded by this last. Finally the control system will move the robot in a work cycle that is described by means of the points selected and recorded as described above. Tests have been carried on with a robot prototype that was designed and built at our Laboratory and showed a very good behaviour of the system.