Ettore Pennestrì

An atlas of linkage-type robotic grippers

In this paper an atlas of 64 linkage-type grippers is presented. For each mechanism one of the possible functional schematic is provided for a better understanding of its kinematic properties. Some of the linkages herein depicted are believed to be novel. The atlas should be helpful to designers in the field of robotics. Graph theory is involved, as far as the concepts of enumeration and isomorphism. The enumeration methodology adopted is described in detail and an extension of the concept of isomorphism to the class of actuated mechanisms briefly recalled.

Comfort analysis of car occupants: comparison between multibody and finite element models

This paper deals with numerical models developed in order to simulate the vibrational and postural comfort of car occupants. The proposed models have been based on different mathematical approaches: the first is a multibody dynamics model and the second is a finite elements model. Both models have been validated by means of static and dynamic experimental tests on vehicles using appropriate test rigs. The authors focus on the advantages and disadvantages of each model in order to have useful information about which approach has to be used to predict objectively the comfort of driver and passengers.

An application of the Udwadia-Kalaba dynamic formulation to flexible multibody systems

Abstract For the transient response analysis of a flexible slider-crank mechanism, the coordinate partitioning scheme and the Udwadia–Kalaba formulation are herein compared. The flexibility of the coupler has been modelled by means of a single Timoshenko beam element. The present analytical treatment can be viewed as an extension of the model discussed by Shabana in his textbook.

Theoretical and Experimental Efficiency Analysis of Multi-Degrees-of-Freedom Epicyclic Gear Trains

Mechanical efficiency analysis is a fundamental phase in the design of Power Gear Trains (PGTs)transmissions. This paper presents a methodology for computing the mechanical efficiency of Epicyclic Gear Trains (EGTs). A novel feature of this methodology is the capability to take into account load dependent power losses and inertia effects. Finally, the paper describes an apparatus used for the experimental validation of the proposed methodology.

Linear Dual Algebra Algorithms and their Application to Kinematics

Summary. Mathematical and mechanical entities such as line vectors, screws and wrenches can be conveniently represented within the framework of dual algebra. Despite the applications received by this type of algebra, less developed appear the numerical linear algebra algorithms within the field of dual numbers. In this paper will be summarized different basic algorithms for handling vectors and matrices of dual numbers. It will be proposed an original application to finite and infinitesimal rigid body motion analysis.

Dynamic Analysis of Epicyclic Gear Trains by Means of Computer Algebra

The paper illustrates the application of a systematic technique for thededuction of dynamic equations of epicyclic gear trains. The use of theproposed method is particularly amenable in conjuction with proceduresfor the computerized enumeration of geared kinematic chains. Thediscussed examples illustrate how the presented approach can be extendedfor computing the equivalent inertia of an epicyclic gear train or forthe stability analysis of 2 d.o.f. gear trains.

Kinematic and Dynamic Analyses of the Tripode Joint

This paper is concerned with an application of multibody techniques to the dynamic analysis of the tripode joint. The purpose of the mathematical model developed is the computation of all the constraint forces. In fact, the results of this investigation are preliminary for a study on the influence of geometry and inertia design parameters on the noise and vibrations caused by the joint.

DYNAMIC, MECHANICAL EFFICIENCY, AND FATIGUE ANALYSIS OF THE DOUBLE CARDAN HOMOKINETIC JOINT.

Cardan and double Cardan homokinetic joints have a wide spectrum of application in vehicle design. This paper proposes mathematical models for mechanical efficiency and torque analysis. The problem of fatigue analysis has been adressed. In particular, it has been investigated the influence of working parameters on the life expectancy of the joint. Design charts have been prepared for a ready use of the proposed models.

Multibody dynamics in advanced education

The use of multibody dynamics software in industrial firms is steadily increasing. Engineering curricula often do not include mandatory courses where multibody dynamics is taught. This paper discuss some relevant teaching issues in this specific cultural area. Noteworthy examples of the great variety of kinematic and dynamic formulations, available for teaching a basic course in multibody dynamics, are illustrated. The experience of the first author, when introducing a basic multibody dynamics course at an Italian university, is also reported.

Dynamic Simulation of a Metal Belt CVT Under Transient Conditions

Most of the technical literature on CVT consider steady-state conditions. Very few analyze the behavior of CVT under transient conditions (Kanehara et al., 1999; Ide et al., 1995; Carbone et al., 2002) and none of them include the effects of pulley deformation. This paper is an attempt to fill the gap. It is herein presented a mathematical model of a V-belt metal CVT, valid also under transient conditions, where the pulley deformation has been included. The model, implemented in a numerical code, combines Gerbert’s theory of V belts and the contributions of (Sattler, 1999a; Sattler, 1999b) on pulley deformation. An innovative algorithm for the simulation of dynamic effects during shifting is proposed. Inertia effects as well as deformation of pulleys are taken into account. Two type of working conditions have been experimentally monitored and numerically simulated. Finally, the paper contains a description of the experimental apparatus used for the validation of the model herein presented.© 2002 ASME