Progetto Leonardo, Esculapio Ed., Bologna, 1995/97/99.
This book deals with digital control systems, i.e. systems based on digital computers as active components of the control loop. In details, the developed material is the following:
Pitagora ed., Bologna, 1995.
This book presents the material offered in the video lesson module described in a previous reference. The book has an "open structure" constituted by the schemes of the lessons, diagrams and figures, permitting an easy participation to the video lessons. Moreover, a number of exercices and design cases is included for home study.
corso di 40 ore in video, DU di Ingegneria Informatica e Automatica prodotto dal Consorzio NET.T.UN.O., diffusione RAI-1, 1995.
This lesson module (40 hours in video) is given at the 3rd year of the D.U. on Informatics and Automatics Eng. and offered in distance-form at the University of Bologna via TV broadcasting by RAI. The content has been coordinated by the Consortium NET.T.UN.O. as follows:
3^ Conferenza ANIPLA su Tecnologie Emergenti in Automazione ed Elettronica Industriale, Milano, Feb. 22 1995. Also in Automazione e Strumentazione, vol. ..., no. ..., ... , 1996.
IEEE Trans. on Robotics and Automation, Jun. 1995, Vol. 11, No. 3, pp. 462-468.
This paper demonstrates fundamental problems with dexterity measures found throughout the robotics literature and offers a methodology for correcting those problems. Measures of robot dexterity derived from eigenvalues, eigenvectors, similarity transformations, singular-value decompositions and the Moore-Penrose inverse of the manipulator Jacobian do not have invariant physical meaning. The apper presents manipulability ellipsoids and manipulability screw-subspaces for both redundant and nonredundant manipulators.
submitted to European J. of Control, (June 1995).
A fuzzy controller formal synthesis procedure based on the well known Variable Structure Control (VSC) theory is described and analyzed. The proposed fuzzy controller paradigm refers to the Takagi-Sugeno-Kang (TSK) method of reasoning, and has a fuzzy antecedent part and a crisp consequent part. The parameters of the fuzzy controller are derived from VSC design considerations. In fact, the underlying idea is to generate a set of VS controllers each of them related to a interpolatory capability of the fuzzy paradigm in order to merge all the VS behaviors in only one structure. A further enhancement is also to provide the fuzzy controller an on--line adaptation mechanism for achieving a fine-tuning property of the fuzzy controller. A stability analysis is then developed in order to give sufficient conditions assuring the closed loop globally stable and robust with respect to bounded disturbance and modeling uncertainties. Finally, a simple simulation example illustrates the main properties of the proposed adaptive fuzzy controller.
EAEEIE Sixth Annual Conf., Bologna, 31th May-2nd June 1995.
A co-operative initiative between a group of SMEs and the LAR-DEIS is illustrated. The technical activity deals with the design of new architectural solutions for automatic packaging machinery based on the use of controlled electrical actuators. At the first stage, several work group from mechanics to computer-control areas explored innovative solutions to problems of machine design, materials use, vibration and noise, and automation of assembly. In the second phase, the activity has been focused on the topic of motion control and CAD tool development. The report discusses both the motivations of the cooperation and the obtained results.
TELEMAN Research Conf., Noordwijkerhout, the Netherlands, 2-5 July 1995.
Proc. of European Control Conference, ECC '95, Rome (Italy), Sep. 1995.
The VSC (Variable Structure Control) with SM (Sliding Mode) dynamics is a well known theory used to define a robust controller for a plant in the presence of model uncertainty and disturbance input. In this paper a method for defining a Sugeno type of Fuzzy Logic Controller (FLC) parameters, derived from VSC design considerations, is proposed. The idea is to generate a set of VSC controllers, related to different bounds on model uncertainties and disturbances, and use the interpolatory capability of the fuzzy paradigm to merge the VSC behavior in only one structure. Moreover a heuristic algorithm for the on-line FC parameter tuning is given. The global stability of the proposed controller is also demonstrated.
Simulations show that the FC obtained performs better than the basic VSC counterpart in the presence of unmodeled dynamics and disturbances.
ECC'95, Roma, Sept.1995.
opening of a semiplenary session, ECC'95, Roma, 1995.
Giornata di Studio ANIPLA, Milano, Oct. 12, 1995.
Nella pratica industriale si utilizzano molto spesso regolatori a struttura fissa in cui e' possibile modificare il valore di alcuni parametri per ottenere prestazioni soddisfacenti. La struttura funzionale di questi regolatori e' quella di tipo PID cioe' ad azione proporzionale, integrale e derivativa. I pacchetti software che realizzano PID digitali di tipo industriale consistono in un insieme di routines che sviluppano non solo l'algoritmo di regolazione in quanto tale, ma permettono anche di gestire la configurazione dell'algoritmo, la presenza di ritardi nel processo, il passaggio bumpless manuale-automatico, la saturazione dell'attuatore e spesso anche il tuning automatico dei parametri. Inoltre, le prestazioni di un regolatore digitale possono dipendere dalla strutturazione dell'algoritmo, dall'aritmetica di elaborazione, dalla precisione nella memorizzazione dei parametri e dalle proprieta' di filtraggio antialiasing. Infine, esiste una interdipendenza di alcune di queste caratteristiche con la scelta del periodo di campionamento. In questo lavoro si raccolgono alcuni elementi di guida alla realizzazione ingegnerizzata degli algoritmi di controllo digitale e si illustrano tipiche soluzioni relative ai vari aspetti sopra citati.
MATLAB Conference, Bologna, 6-7 Nov. 1995. See also MATLAB SIMULINK Connections, Preprint 1995.
The software ProMAP permits the design and the evaluation by simulation of subparts of an automatic machine. In particular, the package is oriented to the general solution of kinematic, dynamic and energy problems raising in the study of kinematic chains for the transmission and coordination of given mouvements with prescribed specifications of velocity, acceleration, and jerk in the duty cycle. ProMAP is based on MATLAB/SIMULINK and performs the following analyses:
A wide library of blocks representing the most used kinematims, actuators and control devices is present. Each block can be parametrized according to the specific analysis of interest.
submitted to European Journal of Control, 1996.
A fuzzy controller formal synthesis procedure based on the well known Variable Structure Control (VSC) theory is described and analyzed. The proposed fuzzy controller paradigm refers to the Takagi-Sugeno-Kang (TSK) method of reasoning, and has a fuzzy antecedent part and a crisp consequent part. The parameters of the fuzzy controller are derived from VSC design considerations. In fact, the underlying idea is to generate a set of VS controllers each of them related to a different plant model and disturbance estimation and to use the interpolatory capability of the fuzzy paradigm in order to merge all the VS behaviors in only one structure. A further enhancement is also to provide the fuzzy controller an on-line adaptation mechanism for achieving a fine-tuning property of the fuzzy controller. A stability analysis is then developed in order to give sufficient conditions assuring the closed loop globally stable and robust with respect to bounded disturbance and modeling uncertainties. Finally, a simple simulation example illustrates the main properties of the proposed adaptive fuzzy controller.
submitted to ICRA'96, IEEE Int. Conf. on Robotics and Automation, Minneapolis, MN, April 22-28, 1996.
In this article, two techniques for slip detection with a rubber-based tactile matrix sensor are presented. The described results have been obtained within a common research activity between the Robotics and Automation Laboratory of the University of Bologna and the Control Laboratory of the Delft University of Technology. The first technique is based on a frequency analysis of the position of the center of force distribution. The main idea is that before a slip situation really occurs, it is possible to detect a micro movement of the object due to the elasticity of the rubber. By implementing a FFT of the center of distribution and by testing the frequency components the slip is identified before it practically occurs. The second approach is based on the principle that the normal forces measured by the tactile sensor fluctuate with a certain frequency during slip because of the rubber elasticity. This fluctuation is due to a `catch and snap back' effect, which is present when an object is slipping over the sensor's surface. By testing the frequency domain of the normal force a slip condition can be detected an even predicted. A comparison between the two approaches is presented and discussed on the basis of experimental results obtained in both laboratories.
Proc. IFAC '96, S.Francisco (CA), Jun. 1996.
In this paper a method developed by the authors for defining a Sugeno-Takagi Fuzzy Logic Controller parameters is illustrated. The procedure, based on the Variable Structure System approach, defines an adaptive fuzzy control structure. In order to show the effectiveness of the proposed solution, the controller is applied to a known benchmark control problem and the obtained simulation results are discussed.
IFAC World Congress, S.Francisco, July 1996.
submitted to 27th Int. Symp. on Ind. Robotics, ISIR'96, Milan, Italy, Oct. 6-8, 1996.
In advanced robotic applications, information about applied wrenches and contact features are a key factor for a full exploitation of the manipulation capabilities of the robotic device. Tactile sensoriality is in fact required in order to realize explorative and reactive capabilities, and in general when an interaction with the environment has to be skillfully performed by the robotic device.
The development of an intrinsic tactile sensor has been realized within the UB Hand II project during the last years by the electrical and mechanical departments, DEIS and DIEM, of the University of Bologna. The sensor consists of a parallelepipid mechanical structure supporting the external shell of the finger. Eigth metallic strain-gauges are glued to the mechanical element in order to acquire signals caused by deformations of the beam of the sensor. With this sensor, it is possible to measure the applied wrench as well as to determine the contact point on the external shell.
Moreover, other sensing principles have been more recently taken into account. Tactile matrix sensors have been considered, and in particular aspects such as object recognition, contact point position, pressure measurement, incipient slip detection and control using tactile information have been investigated. To this purpose the tactile matrix sensor designed and manufactured at the Electronic Instrumentation Laboratory of the Delft University of Technology has been used within a cooperation research activity. The sensor consists in a 16 x 16 taxel matrix and a rubber whose resistance changes with the applied force.
In this paper some aspects of the fusion of the information obtained from both the sensors are presented. In particular, friction coefficient measurements are considered and control issues are addressed in order to assure a stable grasp in presence of external disturbing wrenches. The main idea is to detect an incipient slip situation by means of tactile information and to calculate the friction cone using the force sensor.
Moreover, experimental activity is carried out in order to show possibilities and results obtained using both the force sensor and the tactile sensor measurement within the control scheme. Tactile information about surface features, such as shape, orientation and position of the object, can be used within different control strategies for regrasping procedures and control.
27th Int. Symp. on Ind. Rob., ISIR'96, Milan, Oct. 6-8, 1996.
The report illustrates the research activity currently present at the LAR-DEIS, with particular reference to the area of Robotics, i.e.:
Both research perspectives and partial obtained results are discussed.
Springer, LNCIS No. 215, 1996.
The book illustrates recent developments of Automatic Control, as a science and a technology, through the lectures of outstanding personalities in the fied, in occasion of 50 years of research and teaching activity in this area. The book is related with the COLLOQUIUM'96 ON AUTOMATIC CONTROL organized at the University of Bologna, June 10, 1996. In the book the following lectures are collected:
World Scientific Publ., Singapore, 1996.
This book collects the research contributions presented at the Research Workshop of ERNET, European Robotics Network, held in Darmstadt, on September 9-10, 1996.
ERNET is a research network with 28 partners established for the period 1993-1996 by the European Commission in the framework of the Human Capital and Mobility Programme. Favouring closer contacts among leading research centers in robotics in order to facilitate the exchange of personnel and expertise was among the main goals of this initiative. More than 50 exchanges have taken place within ERNET, originating a relevant number of joint research results. In this book, only some of these results are presented, since it is likely that the authors have also had other opportunities to publish their work.
In any case, the activities described in the 30 articles in this book represent a significant sample of the robotics research carried out in the European context. The articles have been classified according to the following areas: Force Control, Manipulation, Modelling and Control, Mobile Robots, Vision-based Systems, Advanced Sensing, Assembly and Path Planning, Control Architectures, and represent a balanced view of both methodological and technological aspects.
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