Showing papers presented at "Mediterranean Conference on Control and Automation in 2003"

Supremica - A Tool for Verification and Synthesis of Discrete Event Supervisors

Abstract: A tool, Supremica, for automatic verification and synthesis of controllers for discrete event systems is presented. In addition to algorithms for verification and synthesis, Supremica can automatically generate code for a number of languages including ANSI C and IEC 61131 languages like Structured Text and Instruction List. Supremica has built in support for executing the supervisors against either a simulated environment or a physical environment. To handle verification and synthesis of industrial size problems Supremica implements algorithms that exploits the modular structure of the problem together with symbolic methods to efficiently represent large state-spaces.

Solving Algebraic Riccati Equations with SLICOT

Abstract: The numerical solution of algebraic Riccati equations is a central issue in computer-aided control systems design. It is the key step in many computational methods for model reduction, filtering, and controller design for linear control systems. We discuss recent advances in the solvers for continuous-time and discrete-time algebraic Riccati equations available in the SLICOT Library (Subroutine Library In COntrol Theory) and compare their performance with the corresponding solvers in the Matlab toolboxes. Keywords— algebraic Riccati equations, numerical algorithms, computer-aided control system design, numerical linear algebra, software library

Automatic Tuning of Electronic Throttle Control Strategy

Abstract: Electronic throttle is a DC servo drive which provides precise, drive-by-wire positioning of the throttle plate. The electronic throttle body (ETB) parameters can significantly vary due to production deviations, variations of external conditions (e.g. temperature), and aging. In order to avoid the influence of ETB parameters variations to the electronic throttle control performance, an electronic throttle auto-tuning procedure is proposed in the paper. The auto-tuner tunes the parameters of electronic throttle control strategy based on the results of on-line identification of linear and nonlinear process dynamics. The main characteristics of the auto-tuner are good tuning accuracy, short tuning interval (about 1.5 seconds), and simple implementation. In addition, it does not require any prior knowledge of ETB parameters. The auto-tuner is verified experimentally.

analysis on the Influence of Backlash and Motor Input Voltage in Geared Servo System

Abstract: This paper analyzes how the input voltage of the motor and the magnitude of the total backlash of a servo system with a gear reducer affect the frequency response characteristic of the servo system. The bandwidth of the system is defined as the anti-resonance frequency, which appears in the frequency response characteristic. It is found that the amount of system’s bandwidth reduction due to the backlash changes greatly with motor input voltage. It is also shown that when the motor input voltage is infinite, the servo system has a bandwidth of the system that does not have any backlash. Through this work, it has become possible to determine the maximum permissible magnitude of total backlash to satisfy the desired bandwidth for a servo system with a gear reducer.

Metrics for QoS in Real-Time Interaction over the Internet

Abstract: Keywords: Quality of service ; Internet ; metrics ; real time ; interaction Reference LA-CONF-2003-016 URL: http://med03.rasip.fer.hr/ Record created on 2004-11-26, modified on 2017-05-10

On velocity observers for a planar robot subject to non-smooth impacts

Abstract: The goal of this paper is to compare the performances of two different velocity observers, a full order one and a reduced order one, when used to estimate the velocity vector of a planar robot subject to impacts with the environment, modelled as perfectly rigid. Both the sensitivity of the observers to quantization errors in the position measurements and their behaviour in closed-loop are investigated. Keywords— Mechanical systems, non-smooth impacts, velocity observers.

State observers for the asymptotic inversion of nonlinear maps, when the reference trajectory is not differentiable

Abstract: In this paper, we deal with the problem of the inversion of nonlinear maps, when the reference trajectory is not differentiable, thus extending previous works. First, we give the definition, in a formal framework, of a problem related to map inversion, which is already present in the literature, for instance in the robotics area and in observer theory: the inverse kinematics problem and the inversion of the nonlinear observability map. Secondly, we give the solution of such a problem by means of an asymptotic observer, for which a structure is proposed, for the state estimation of a time-varying nonlinear system associated with the given map and reference trajectory. Keywords— Asymptotic nonlinear map inversion, observers, non-smooth trajectories, non-smooth impacts.