41 research outputs found
A Design Pattern for translating UML software models into IEC 61131-3 Programming Languages
No full textThe paper deal with a deep analysis and application of object-oriented methodologies for the design process of industrial machine controllers. The process pass thought the phases of (1) conceptual model development of the software artifacts, and (2) model code deployment for the automation system target, which is in general a Programmable Logic Controller (PLC) compliant with the international standard IEC 61131-3 for programming languages. The paper describes a design pattern for the software conceptual model deployment, with a particular emphasis on practical requirements enforced by PLC of different brands. In fact, IEC 61131-3 compliance provides a common ``look-and-feel'' for programming languages, but does not guarantee straightforward code portability between different PLC vendors. The paper has a great focus on applications and provides an example, based on a generic flow-pack machine, to better explain the proposed methodology
Variable Structure PID Based Visual Servoing for Robotic Tracking and Manipulation
No full textThis paper presents a practical experiment on the use of visual servoing for robotic tracking and manipulation of objects moving on a plane. In this work, the image is acquired from the camera mounted on the end-effector of a 6 DOF industrial robot, and processed on a standard PC-based vision system in order to close the visual servoing loop with a PID based controller. The PID has been implemented with a variable structure, modified according to the estimated velocity of the target, in order to achieve a good step response and to eliminate steady-state error with a moving target. The possibility to perform a stable tracking and to estimate the target dynamics allows also to grasp the object with a prediction based trajectory planning
Active Fault Tolerant Control Scheme for a General Aviation Aircraft Model
No full textThis paper addresses the development of a novel active
fault tolerant control scheme. The methodology is based on a
fault detection and diagnosis procedure relying on adaptive filters
designed via the nonlinear geometric approach. The controller
reconfiguration exploits a further control loop, depending on the
on-line estimate of the fault signal. One of the advantages of this
strategy is that, for example, a structure of logic–based switching
controller is not required. The active fault tolerant control scheme
is therefore applied to a PA–30 aircraft simulator in several
flight conditions, in the presence of actuator faults, turbulence,
measurement noise, and modelling errors. The achieved results
in faulty conditions show the enhancement of the flying quality,
the asymptotic fault accommodation, and the control objective
recovery
Robotic manipulation experiments through visual feedback
No full textThis paper presents an experimental study on the use of visual servoing for dexterous robotic manipulation. In the first step of the work, a mathematical model of the whole system has been derived, then a non – linear PID regulator with Smith predictorstructure has been developed. The feedback signal for the controller comes directly from the visual sensor. Some experiments on following with robot end-effector a moving target have been performed, showing efficiency of the control system.This work on visual feedback differs from other similar experiments mainly because the inner architecture of the robotcontroller is assumed unknown, i.e. the inner control loop of the robot has not been modified
Design and Verification of Industrial Logic Controllers with UML and Statecharts
No full textThe paper describes a methodological framework that aims to apply formal design and verification techniques to the domain of Logic Control and Supervision for Manufacturing Systems. The methodology is based on a Object-Oriented approach, supported by a syntactical and semantical adaptation of the semi-formal software specification languages UML and Statecharts. The modeling languages has been subsequently formalized, according to a semantics that take into account the concepts described in the IEC 61131-3 Standard for industrial controllers programming, in order to prove correctness properties expressed in the temporal logic CTL. The verification process is performed by means of the model checking tool SMV
APPLICATION OF FAULT DIAGNOSIS METHODOLOGIES TO A GENERAL AVIATION AIRCRAFT
No full textThis paper addresses the problem of the detection and isolation of
input sensor faults on a general aviation aircraft, characterised by a nonlinear model, in the presence of wind gust disturbance and measurement errors. In particular, this work studies and compares different residual generator designs in order to realise complete diagnosis schemes, when additive faults are present.
These different methods comprise linear and nonlinear filters, neural networks and unknown input Kalman filters, that can achieve disturbance signal de–coupling and robustness properties with respect to modelling error and sensor measurement noise. The results obtained in the simulation of the faulty behaviour of a PIPER
PA30 longitudinal aircraft model are finally reported
Design of residual generators and adaptive filters for the FDI of aircraft model sensors
No full textThe main contribution of this paper is the description and application of a comprehensive set of
methodologies for fault detection and isolation (FDI) of aircraft sensors. In particular, a new nonlinear
geometric approach (NLGA) and an efficient linear polynomial method (PM) are presented and
compared, together with simulation results obtained from a commercial aircraft model. Adaptive filters
with disturbance decoupling for fault identification are designed via the developed NLGA-based
method. On the other hand, the FDI scheme based on linear PM exploits a disturbance decoupling
technique in connection with a linear dynamic filter design procedure. The FDI strategies are applied to
the aircraft simulator data in a flight condition characterised by tight–coupled longitudinal and lateral
dynamics. Moreover, in order to analyse robustness and reliability properties of the two FDI schemes,
extensive simulations are performed in the presence of turbulence, measurement noise and modelling
errors
Application of object-oriented modeling tools to design the logic control system of a packaging machine
No full textThe paper presents the results of an application of object-oriented modeling techniques to design manufacturing systems logic controllers. In particular, the semantical aspects of specification languages like UML and Statecharts, widely used in many Software Engineering methods, are analysed and discussed, with regard to their adequacy for the industrial domain and their verification with formal methods. The paper ends with the description of a practical case of study, which shows that the proposed design and verification techniques can be successfully adopted in a real industrial framework, given domain-specific adaptation of object-oriented modeling languages
Residual Generator Function Design for Actuator Fault Detection and Isolation of a Piper PA 30 Aircraft
No full textThis paper addresses the problem of the detection
and isola!ion of actuator fauIts on a general aviation aircraft,
characterised by a nonlinear model, in the presence of wind
gust disturbances. In particular, this work investigates the
design of residual generators in order to realise complete
diagnosis schemes when additive faults are present. The
use of a canonical input-output polynomial description for
the hearised model of the aircraft allows to compute in
a straightforward way minimal order residual generators.
These tools lead to dynamic filters that can guarantee both
disturbance signal decoupling and robustness properties with
respect to linehation errors. The results obtained in the
simulation of the Faulty bebaviour of a Piper PA30 are aaUy
reported
Design and Verification of Mechatronic Object-Oriented Models for Industrial Control Systems
No full textThe paper describes a methodological framework that aims to apply formal design and verification techniques in the development of Industrial Control Systems, with particular regard to the domain of manufacturing machines. The methodology is based on an Object-Oriented approach, revisited in a mechatronic perspective
