Adam Pilat

Real-time controller design based on NI Compact-RIO

The paper is focused on NI Compact-RIO configured as a controller for the active magnetic levitation used here as a benchmark for time-critical systems. Three real-time configurations: soft, soft with IRQ and hard FPGA are considered. The quality of the real-time control has been tested for each configuration.

Industry feedback on skills and knowledge in real-time software engineering

Rapid progress of computing technologies is the major reason that the programs like electronics, computer and software engineering, robotics and control engineering need continuous updates. This paper is related to the development of an international curriculum in real-time software engineering. It focuses on identification of skills, attitude and knowledge the students need to acquire to become efficient engineers working in the field. To facilitate this objective, a survey administered to industry representatives in four countries is described and its results are discussed.

Investigation of chained analog signal processors in programmable analog computer

This elaboration presents a new device based on dynamically programmable Analog Signal Processors (dpASP) developed for hard real-time control applications. The developed Programmable Analog Computer/Controller (PAC) is an open hardware for a wide range of signal processing tasks. In this report the analog signal routing and filter based signal processing realized by the dpASP is presented. This research was focused on the signals form as they are processed and transferred between analog processors. The investigation is exampled by the low-pass filter(s) embedded into every analog processor. For complex signal processing tasks a few dpASP must be routed together. The dpASP chain is created for signal diagnosis and due to the limited resources of a single device. Final conclusions related to chaining analog processors are given.

Control Toolbox for industrial Programmable Analog Controller — Embedding state feedback controller

The aim of this paper is to present the research on the Control Toolbox for the device named Programmable Analog Controller. This unit is based on dynamically programmable Analog Signal Processors. The configurable hardware resources require automated or semi-automated methods to support the configuration and signal processing stage. In this paper the research on the state of feedback controller design and implementation is provided. The limited hardware resources and specific type of signal processing require the performance the detailed analysis and configuration validation and verification. To compare the controller configurations, the experimental results are plotted to illustrate the controller calculation.

HARDWARE AND SOFTWARE ARCHITECTURES FOR RECONFIGURABLE TIME-CRITICAL CONTROL TASKS

The most popular configuration of the controlled laboratory test-rigs is the personalcomputer (PC) equipped with the I/O board. The dedicated software components allowsto conduct a wide range of user-defined tasks. The typical configuration functionality canbe customized by PC hardware components and their programmable reconfiguration. Thenext step in the automatic control system design is the embedded solution. Usually, thedesign process of the embedded control system is supported by the high-level software. Thededicated programming tools support multitasking property of the microcontroller by selectionof different sampling frequencies of algorithm blocks. In this case the multi-layer andmultitasking control strategy can be realized on the chip. The proposed solutions implementrapid prototyping approach. The available toolkits and device drivers integrate system-leveldesign environment and the real-time application software, transferring the functionality ofMATLAB/Simulink programs to PCs or microcontrolers application environment.

Time-Optimal Control Supported by PD in Real-Time* *

Abstract The Magnetic Levitation System (MLS) is ideal for modelling because it is frictionless. With a model well-fitted to the system one can generate adjoint equations and solve both the state and adjoint differential sets numerically to obtain the time-optimal sequences corresponding to the desired initial and final positions of the levitating sphere. This action is repeated for a broad set of the sphere position differences. The resulting bang-bang controls are associated with the sphere levels and stored in the computer memory. Each sphere level is equipped with an appropriately tuned PD controller to maintain levitation. This means that the damping and elasticity coefficients are sustained at the values close to each other despite changes of the distance between the sphere and electromagnet. In this way the time-optimal, open-loop control applied for the position change aided by the PD controller at steady states becomes a variable control structure and appears to be the correct and rapid strategy to experiment with MLS in the real-time.

Inter-university project based on LEGO NXT

The paper describes the mechanism for involving students from multilingual, geographically separated institutions in a coordinated educational experience and presents the observations and evaluation of outcomes related to the collaborative project. The project was realized as a part of ILERT (International Learning Environment for Real-Time Software Intensive Control System) EU/US activity sponsored by FIPSE/EC Atlantis Program. As a part of the pilot implementation phase of the ILERT project, international students teams have worked on robotic design and control experiments with LEGO MINDSTORMS NXT kits. The project has engaged on-site students and faculty of universities from four countries (USA, Poland, France, and Czech Republic). The robot maze navigation problem has been defined as an example. LEGO-MINDSTROMS NXT kit has been selected as a common platform for students teams. A Web-based Project Management System (WebPMS) has been used to improve communication and test Internet based tools for inter-university collaboration. Final evaluation of the project outcomes, including students survey results, are presented in this paper.

Modelling, investigation, simulation, and PID current control of Active Magnetic Levitation FEM model

This elaboration presents the numerical model of the Active Magnetic Levitation (AML). The model is developed in the 2D axis symmetry mode. The Finite Element Method is used to calculate the magnetic field. The Ordinary Differential Equation is solved simultaneously to simulate the levitated object motion. The model is solved in the time domain, together with the levitated object motion being simulated. A few investigation simulations are realized to diagnose the basic properties of the model. The PID current mode controller is used to drive the coil and keep the object levitated in the desired position. The electromagnetic force and magnetic flux density are investigated to analyze the AML non-linearities. Finally, the conclusions towards the experimental research are given.

Zero-point drift in low-frequency mechanical spectroscopy

The concept of the ‘zero-point drift’, ZPD, is introduced and analyzed on the basis of mechanical loss measurements carried out in a low-frequency mechanical spectrometer – inverted torsion pendulum. It is demonstrated that the ZPD, which modifies damped harmonic oscillations leads to false values of the logarithmic decrement computed from several widely accepted algorithms.

A Comparative Study of PI λ D μ Controller Approximations Exemplified by Active Magnetic Levitation System

The PI λ D μ DFOC was examined when applied to the Active Magnetic Levitation System. This research is based on the Prof. Ivo Petras Toolbox for fractional controller synhesis. The point of interest is the PID configuration applied at the simulation and experimental stages. The search for the optimal controller form is dependent on the quality measure in the transition phase when the external excitation load is activated. The digital control experiment was carried out in the MATLAB/Simulink using a USB I/O board. The controller realisations are compared and discussed.