Jordan Kralev

μ-Synthesis and Hardware-in-the-loop Simulation of Miniature Helicopter Control System

The aim of this paper is to describe in detail the μ-synthesis of a miniature helicopter integral attitude controller of high order and to present results from the hardware-in-the-loop simulation of this controller implementing Digital Signal Processor. The μ-controller designed allows to suppress efficiently wind disturbances in the presence of 25 % input multiplicative uncertainty. A simple position controller is added to ensure tracking of the desired trajectory in 3D space. The results from hardware-in-the-loop simulation are close to the results from double-precision simulation of helicopter control system in Simulink®. The software platform developed allows to implement easily different sensors, servoactuators and control laws and to investigate the closed-loop system behavior in presence of different disturbances and parameter variations.

Design of Embedded Robust Control Systems Using MATLAB® / Simulink®

Robust control theory allows for changes in a system whilst maintaining stability and performance. Applications of this technique are very important for dependable embedded systems, making technologies such as drones and other autonomous systems with sophisticated embedded controllers and systems relatively common-place. The aim of this book is to present the theoretical and practical aspects of embedded robust control design and implementation with the aid of MATLAB® and SIMULINK®. It covers methods suitable for practical implementations, combining knowledge from control system design and computer engineering to describe the entire design cycle. Three extended case studies are developed in depth: embedded control of a tank physical model; robust control of a miniature helicopter; and robust control of two-wheeled robots. These are taken from the area of motion control but the book may be also used by designers in other areas. Some knowledge of Linear Control Theory is assumed and knowledge of C programming is desirable but to make the book accessible to engineers new to the field and to students, the authors avoid complicated mathematical proofs and overwhelming computer architecture technical details. All programs used in the examples and case studies are freely downloadable to help with the assimilation of the book contents.

Identification and synthesis of linear-quadratic regulator for digital control of electrohydraulic steering system

The main objective of this work is to present the designed system for control of electrohydraulic steering system that is implemented in low speed mobile machines. The goal of control algorithm is to achieve fast transient response without overshooting and static error in whole working range. To achieve this aim first a multivariable dynamical plant model is estimated by identification procedure. The model obtained is validated by various statistical tests. The multivariable LQR regulator with integral action and Kalman filter are designed. Appropriate software which is implemented in 32-bit microcontroller is developed. Experimental results are presented which confirm that the control system achieves the prescribed performance.

Design of digital PI regulators from experimental frequency response of electrohydraulic steering system

Paper presents the tuning of two digital PI regulators for electrohydraulic steering system designed for low velocity mobile machines. Regulators are based on experimentally measured frequency response of a steering system. This response is approximated with two rational transfer functions. They are basis for design of corresponding digital PI regulators with iterative optimization procedure in MATLAB / Simulink. Regulator parameters are programmed into a microcontroller for mobile applications and their performances are compared through natural experiment on the steering electrohydraulic drive system with digital control.

Design and experimental evaluation of robust controllers for a two-wheeled robot

ABSTRACT The paper presents the design and experimental evaluation of two alternative μ-controllers for robust vertical stabilisation of a two-wheeled self-balancing robot. The controllers design is based on models derived by identification from closed-loop experimental data. In the first design, a signal-based uncertainty representation obtained directly from the identification procedure is used, which leads to a controller of order 29. In the second design the signal uncertainty is approximated by an input multiplicative uncertainty, which leads to a controller of order 50, subsequently reduced to 30. The performance of the two μ-controllers is compared with the performance of a conventional linear quadratic controller with 17th-order Kalman filter. A proportional-integral controller of the rotational motion around the vertical axis is implemented as well. The control code is generated using Simulink® controller models and is embedded in a digital signal processor. Results from the simulation of the closed-loop system as well as experimental results obtained during the real-time implementation of the designed controllers are given. The theoretical investigation and experimental results confirm that the closed-loop system achieves robust performance in respect to the uncertainties related to the identified robot model.

Design and Implementation of Cascade LQR Controller for Stabilization of Two-Wheeled Robot

Abstract In this paper the developed two-wheeled robot and cascade LQR controller, Kalman filters, PI and PID controllers are presented. The cascade LQR controller stabilizes the two-wheeled robot in upright position. The PID controller ensures good tracking of wheel position reference and the PI controller steers two-wheeled robot rotation around the vertical axis. A software in MATLAB®/Simulink environment intended for design and generation of control code which is embedded in a Texas Instruments Digital Signal Controller is developed. Simulation and experimental results of system performance are given that confirm the efficiency of the control system developed.

Design And Implementation Of Robust Control Laws.

This paper is devoted to various issues related to the design and practical implementation of high order robust control laws. We consider derivation of plant uncertainty models using analytical or identification procedures, implementation of different schemes for μ-synthesis, choice of weighting filters and controller order reduction. Additional important problems arising in the framework of embedded control systems, like removing the sensor drifts, generation of control code from Simulink R ⃝and effect of single precision arithmetic on the controller stability, are discussed in some details. As a case study we present the robust control of two-wheeled robot using μ-controller of order 30. The experimental results confirm that the closed-loop system achieves both robust stability and robust performance in respect to the uncertainties related to the identification of robot model.

Design of UART controller for FPGA with Simulink

Simple UART (Universal Asynchronous Receiver Transmitter) controller, compatible with RS232 standard is implemented on Spartan-3E FPGA, through automatic HDL code generation and hardware synthesis. The paper shows how the design can be entirely conveyed in MATLAB/Simulink® environment. There is no need for additional behaviour description in HDL. Results from simulation and experiments verify functionality of the controller.