The paper deals with the identification of the system parameters in the nonlinear dynamic model o... more The paper deals with the identification of the system parameters in the nonlinear dynamic model of fixed wing UAVs. Fixed wings airplanes are popular in long distance applications and have to be modelled accurately to guarantee efficient control properties. Different methods are suggested to solve the parameter estimation beginning with the standard linear regression (LR) and continued with its extension (ELR), the optimization using interior point methods and finally using the FireFly technique, which is a metaheuristic algorithm. The methods illustrate the convergence and the speed of these approaches. The known default parrameter values of a Sekwa UAV were used to demonstrate that the elaborated identification methods can also reconstruct the numerical values of the dimensionless system parameters embedded into the nonlinear model using the physical weighting functions. After the extension of linear regression, MinMax optimization algorithm was used to get the best and optimal solution and reconstruct the parameters of the Sekwa aircraft. FireFly optimization gives also comparable results with minmax method. Flight data was needed for simulation and testing the different approaches. Matlab and toolboxes were used as simulation software. The results showed the estimated parameters are more accurate than linear regression estimation. Even though it is a small improvment this will reflect in all calculations.
This paper presents two object manipulation planning methods based on fitted stratified and semi-... more This paper presents two object manipulation planning methods based on fitted stratified and semi-stratified approaches using finger relocations. The problem is discussed in the framework of a motion planning problem. The goal of the methods is to steer an object from an initial configuration to a final configuration while it is possible to reposition the fingertips on the surface in a predefined way. We assume there is no rolling and sliding but finger relocations are allowed. The first technique follows a pure stratified approach, however unlike the previously published method, the exact kinematic model of the manipulation system is matched with a virtual model masking the behavior of the original system. This provides a simpler model than the earlier stratified method by reducing the generally hard symbolic computation problem to a simple (almost pure numerical) one. The paper also introduces a semi-stratified manipulation
This paper addresses new algorithms for motion planning of walking robots if they are given by st... more This paper addresses new algorithms for motion planning of walking robots if they are given by stratified holonomic and nonholonomic kinematic models. The mathematical details for general stratified systems are investigated in [1], [2], [3], [4]. The main motivation of our concept is to complete motion planning algorithms that are able to avoid obstacles in the configuration space of walking robots. The proposed methods achieve this goal by leading the robot along a decomposed reference trajectory. Although the reference trajectory should still be restricted, it can be used to obstacle avoidance. The algorithms are demonstrated on an illustrative example of the hexapod robot.
Abstract—The paper introduces a new model to describe the friction phenomenon at low velocities. ... more Abstract—The paper introduces a new model to describe the friction phenomenon at low velocities. The model has the useful property that it is linear in parameters. Using this model robust adaptive control algorithm is developed for high precision positioning. Simulations were performed to show the performances of the applied control algorithm. Keywords—Friction modelling, Friction Compensation, Robust Adaptive Control.
The paper presents a control algorithm for high precision position tracking of the DC motor drive... more The paper presents a control algorithm for high precision position tracking of the DC motor driven mechatronic systems near Striebeck velocities. The algorithm is based on a linearized friction model, which is introduced in the control algorithm and its aim is to compensate the effect of nonlinear friction force. An identification method, to obtain the parameters of the linearized friction model is also presented. Experimental measurements are provided to show the performances of the proposed control algorithm.
IEEE Transactions on Control Systems and Technology, Sep 1, 2015
Many applications require fast control action and efficient constraint handling, such as in aircr... more Many applications require fast control action and efficient constraint handling, such as in aircraft or vehicle control, where instead of the slow online computation of the model predictive control (MPC) the explicit MPC can be an alternative solution. Explicit MPC controllers consist of several affine feedback gains, each of them valid over a polyhedral region of the state space. The exponential blow-up of the number of regions with increasing the prediction horizon increases the searching time among the regions extremely which together with the requirement of the full state measurement decreases its applicability for real systems. First, discrete-time actual Kalman filter is designed for the semiactive suspension and applied to explicit MPC controller that requires only measurement of the suspension deflection. Second, this paper presents a systematic way to design Gaussian radial basis function-based neural network (NN) approximation of the explicit MPC controller and shows that a well-tuned NN with some neurons can replace the explicit MPC controller. This nonlinear state-feedback controller can ensure the fast control action but price of the approximation is some deterioration of the performance value. The complete novel nonlinear control system with Kalman filter is analyzed in detail. The derived controllers are evaluated through simulations, where shock tests and white noise velocity disturbances are applied to a real quarter car vertical model.
Received 2012-06-25, revised 2012-10-11, accepted 2012-10-12 The primary scope of this study lays... more Received 2012-06-25, revised 2012-10-11, accepted 2012-10-12 The primary scope of this study lays on system technique so-lutions of collecting data required for the identification of an aircraft’s nonlinear dynamic model. It is assumed that the aircraft has no inbuilt navigational sys-tem, nor any sensors mounted on its control surfaces. The con-trol column and pedals manipulated by the pilot can only visu-ally be observed. For the time of data logging, an external sen-sory system (GPS, IMU) and a camera system were deployed on the airplane supporting the collection of flight data. The paper presents the data acquisition solutions required for aircraft’s nonlinear model identification, with an emphasis on the determination of the control surface positions as the sys-tem’s input signals using image processing. During flight, the control column and pedal positions manipulated by the pilot are recorded using a video camera and with post processing, data is converted to control surface ...
Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepe... more Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepezik a biztonsagos erőművi es folyamatiranyitasi rendszereknek, robotizalt gyartorendszereknek es az autonom foldi, legi, vizi es űrbeli jarművek iranyitasi rendszereinek. A harom kotetre tervezett sorozat eme utolso kotete a robusztus iranyitasok elmeletevel es tervezesevel foglalkozik. Szerves folytatasa az altalanos rendszertechnikai ismereteket ado első kotetnek es a tobbvaltozos optimalis, nemlinearis es adaptiv szabalyozasok korszerű tervezesi modszereit bemutato masodik kotetnek. A robusztus iranyitasok elmelete arra a kerdesre keres mernoki valaszt, hogyan lehet olyan fix, a tervezes es implementalas utan uzem kozben mar nem valtozo szabalyozot tervezni, amely valtozo szabalyozott szakaszok eseten is biztositani tudja a szabalyozassal szemben tamasztott elvarasok (stabilitas, zavaras elnyomas, kis dinamikus es statikus hiba) teljesuleset. A kotet előszor osszefoglalja a tervezeshez szukseges matematikai alapokat. Az idő- es frekvenciatartomanybeli jelek nagysaganak jellemzesere normakat definial, es bevezeti a targyalasukhoz szukseges Lebesgue- es Hardy-tereket. Megfogalmazza a belső stabilitas elvet es perturbaciok esetere a kis erősites tetelt. Bemutatja a stabilizalo szabalyozok Youla-parameterezeset. A perturbalt rendszer leirasara bevezeti a linearis tort transzformaciokat (LFT). Megadja a stabilizalo szabalyozok allapotteres alakjat. A tervezesi modszerek kozul előszor a linearis rendszer kvadratikus kriterium szerinti optimalis iranyitasaval foglalkozik LTV, LTI es sztochasztikus rendszer eseten. Modszert mutat be a nagy fazistobbletet biztosito hurokatvitel visszaallitasra. Megfogalmazza az altalanos H2 (energia) optimalis szabalyozotervezesi feladatot es megadja az optimalis iranyitas szamitasi modszeret. Ezutan a Hinf optimalis szabalyozas tervezesere mutat be modszereket. Megadja a gamma-optimalis centralis Hinf szabalyozo tervezesi algoritmusat, az integralo szabalyozas biztositasat es a telites kezeleset. Ket megoldast (1-DOF, 2-DOF) mutat be a hurokformalas tervezesere, utobbiban lehetőseget adva referencia modell előirasara is. Az eredmenyeket repulőgep iranyitas eseten illusztralja. Modszert mutat be a Hinf szabalyozo tervezesere mu-analizis, DK-iteracio es LMI technika bevonasaval, melyet az invertalt inga instabil munkapontja koruli szabalyozassal illusztral. Ezutan a kotet bemutatja a nemsima, nemkonvex optimalizalason alapulo előirhato fokszamu es stabil Hinf robusztus szabalyozo tervezesi modszereket es a tervezest tamogato szoftver eszkozoket. A tervezesi modszer lehetőve teszi megvalaszthato fokszamu mintaveteles Hinf szabalyozo es előirt strukturaju analog (pl. MIMO PID) szabalyozok tervezeset, valamint kozos Hinf szabalyozo tervezeset egyszerre tobb szabalyozott szakaszhoz. Pelda mutatja be az optimalizalast az ujabb MATLAB eszkozok bevonasaval is. Vegul a konyv az LPV rendszerek robusztus iranyitasanak bemutatasaval zarul. A modszereket egy pelda illusztralja az ujabb MATLAB eszkozok bevonasaval. A kotet jol hasznosithato az egyetemi szabalyozastechnikai szakiranyu mester- es PhD-kepzesben, es rendszertechnikailag megalapozza a korszerű folyamatiranyitasi, mechatronikai es az autonom (vezető nelkuli) jarműiranyitasi rendszerek tervezeset.
Periodica polytechnica. Electrical engineering and computer science /, Jun 26, 2023
This paper presents the estimation of stability and control derivatives of an unmanned aircraft. ... more This paper presents the estimation of stability and control derivatives of an unmanned aircraft. The aerodynamics are described using regressors composed of velocity, angular rates, flow angles and control surface deflections. The flight data is generated from numerical simulation of postulated equations of motion describing the aerodynamics model. Least squares based on the equation error method is used to estimate the parameters representing the different force and moment aerodynamic coefficients. Statistical analysis is done on the estimates to determine the accuracy and adequacy of the estimates to describe the aerodynamic model. A dynamic simulation based on the identified aerodynamic model is used to improve the parameter estimates through regression of the errors between the flight data and the model response. The aircraft under consideration is a scaled Yak-54 fixed wing unmanned aerial vehicle.
Periodica polytechnica. Electrical engineering and computer science /, May 31, 2022
An estimation model is key in the design and development of an unmanned aerial vehicle's control ... more An estimation model is key in the design and development of an unmanned aerial vehicle's control system. This work presents a complete methodology for modelling the dynamics of a fixed-wing UAV for aerobatic maneuvers. The UAV dynamic non-linear model considered uses total variables instead of a nominal values and perturbation values about certain trimmed conditions for conventional flight envelopes. Such modelling allows the expansion of the flight envelope of an unmanned aerial vehicle to cover the full range of the angle of attack. The quaternion formulation is used since it eliminates the nonlinearity of the aerodynamics due to Euler angles for high angle of attacks. The objective is to have a complete and accurate representation of a highly dynamic fixed wing UAV capable of making aerobatic maneuvers without encountering singularities. A set of controllers are then designed for the inner and outer loops for attitude control using nonlinear dynamic inversion in cascade with a PI controller. Simulations carried out show robust tracking of reference attitude angles.
Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepe... more Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepezik a biztonsagos erőművi es folyamatiranyitasi rendszereknek, robotizalt gyartorendszereknek es az autonom foldi, legi, vizi es űrbeli jarművek iranyitasi rendszereinek. A harom kotetre tervezett sorozat eme utolso kotete a robusztus iranyitasok elmeletevel es tervezesevel foglalkozik. Szerves folytatasa az altalanos rendszertechnikai ismereteket ado első kotetnek es a tobbvaltozos optimalis, nemlinearis es adaptiv szabalyozasok korszerű tervezesi modszereit bemutato masodik kotetnek. A robusztus iranyitasok elmelete arra a kerdesre keres mernoki valaszt, hogyan lehet olyan fix, a tervezes es implementalas utan uzem kozben mar nem valtozo szabalyozot tervezni, amely valtozo szabalyozott szakaszok eseten is biztositani tudja a szabalyozassal szemben tamasztott elvarasok (stabilitas, zavaras elnyomas, kis dinamikus es statikus hiba) teljesuleset. A kotet előszor osszefoglalja a tervezeshez szukseges matematikai alapokat. Az idő- es frekvenciatartomanybeli jelek nagysaganak jellemzesere normakat definial, es bevezeti a targyalasukhoz szukseges Lebesgue- es Hardy-tereket. Megfogalmazza a belső stabilitas elvet es perturbaciok esetere a kis erősites tetelt. Bemutatja a stabilizalo szabalyozok Youla-parameterezeset. A perturbalt rendszer leirasara bevezeti a linearis tort transzformaciokat (LFT). Megadja a stabilizalo szabalyozok allapotteres alakjat. A tervezesi modszerek kozul előszor a linearis rendszer kvadratikus kriterium szerinti optimalis iranyitasaval foglalkozik LTV, LTI es sztochasztikus rendszer eseten. Modszert mutat be a nagy fazistobbletet biztosito hurokatvitel visszaallitasra. Megfogalmazza az altalanos H2 (energia) optimalis szabalyozotervezesi feladatot es megadja az optimalis iranyitas szamitasi modszeret. Ezutan a Hinf optimalis szabalyozas tervezesere mutat be modszereket. Megadja a gamma-optimalis centralis Hinf szabalyozo tervezesi algoritmusat, az integralo szabalyozas biztositasat es a telites kezeleset. Ket megoldast (1-DOF, 2-DOF) mutat be a hurokformalas tervezesere, utobbiban lehetőseget adva referencia modell előirasara is. Az eredmenyeket repulőgep iranyitas eseten illusztralja. Modszert mutat be a Hinf szabalyozo tervezesere mu-analizis, DK-iteracio es LMI technika bevonasaval, melyet az invertalt inga instabil munkapontja koruli szabalyozassal illusztral. Ezutan a kotet bemutatja a nemsima, nemkonvex optimalizalason alapulo előirhato fokszamu es stabil Hinf robusztus szabalyozo tervezesi modszereket es a tervezest tamogato szoftver eszkozoket. A tervezesi modszer lehetőve teszi megvalaszthato fokszamu mintaveteles Hinf szabalyozo es előirt strukturaju analog (pl. MIMO PID) szabalyozok tervezeset, valamint kozos Hinf szabalyozo tervezeset egyszerre tobb szabalyozott szakaszhoz. Pelda mutatja be az optimalizalast az ujabb MATLAB eszkozok bevonasaval is. Vegul a konyv az LPV rendszerek robusztus iranyitasanak bemutatasaval zarul. A modszereket egy pelda illusztralja az ujabb MATLAB eszkozok bevonasaval. A kotet jol hasznosithato az egyetemi szabalyozastechnikai szakiranyu mester- es PhD-kepzesben, es rendszertechnikailag megalapozza a korszerű folyamatiranyitasi, mechatronikai es az autonom (vezető nelkuli) jarműiranyitasi rendszerek tervezeset.
Third-generation robotic systems are intelligent in the sense that they can perform a large reper... more Third-generation robotic systems are intelligent in the sense that they can perform a large repertory of complex tasks under conditions not known a priori. They are usually sensor-coupled using multisensory (vision, force, tactiie, etc.) information about their initial state and environment, have decision-making capabilities, can monitor and modify their plans learning from past experience. They have the properties of flexibility and artificial intelligence. The aim of the book was to provide wide coverage of these concepts based on the latest developments of well-known experts working in academic and research institutions. The book is addressed to scientists, engineers, postgraduate students and professionals working or having interest in intelligent robotics and control. The book is divided in 5 parts containing 18 chapters. Part I is devoted to introductory issues and it consists of Chapter 1: Introduction to Intelligent Robotic Systems written by Tzafestas (National Technical University of Athens,. Greece). The general architecture of intelligent robotic control (consisting of organization, coordination and execution levels), the basic problems of robot modeling and motion control, and the classification of sensors including vision are introduced. Three examples of intelligen t robotic systems are selected from the field of sensor-based (Espirit 278 and Pardue system) and mobile (KAMRO) robots. Part II deals with the structure and programming of intelligent robotic systems. Chapter 2: Theory and Design of Intelligent Robotic Systems by Valavanis (Northeastern University, Boston, Massachusetts), presents a general theory of intelligent machines and robotic systems based on a heuristic probabilistic model and entropy functions to describe the system performance of structures composed of organization, coordination and execution levels. Chapter 3: Hierarchy oj Intelligent On-Line Execution by Kelley (Rensselaer Polytechnic Institute, Troy, New York) deals with a robotic assembly system that allows both automatic programming and execution despite uncertainties in the task environment. The principle ofleast commitment is followed, and the system is partitioned into off-line (planners, specialists) and on-line (supervisor, specialists, interfaces) modules. Some details are given for the design of the supervisor and its implementation with 4 specialists on VAX running under Unix. Chapter 4: Skill-Based Expert Systems in Robotics by Tomovic (University of Belgrade, Yugoslavia), deals with the skill level (functional motion of human extremities) of a hierarchical control structure using both numerical and non numerical models. It concentrates on multifinger robot hands and describes the hand mechanics, sensors and local controllers of the Belgrade-USC Hand, and the multilevel manipulator control using computer vision and expert system (for preshaping, grasping mode, etc.
Journal of Advanced Computational Intelligence and Intelligent Informatics, Nov 20, 2007
This paper addresses the predictive control of the harmonic drive in an automotive application. T... more This paper addresses the predictive control of the harmonic drive in an automotive application. The goal of the control was to provide good steering feel for the driver and satisfactory tracking performance in a steering system. The paper presents the dynamic model of the harmonic drive, a design framework and a two step algorithm for predictive controller design. The elaborated model predictive controller is similar to a cascade type controller with constraints in the performance function to ensure closed loop stability and a useful compromise between torque tracking and position tracking. The controller was developed and implemented in a real-time environment for rapid prototype design using Matlab, Simulink, Real-Time Workshop and dSPACE AutoBox hardware, then it was experimentally tuned for best steering feel and good tracking performance.
Simulation tools can support robot control design and help to find the most critical parts of the... more Simulation tools can support robot control design and help to find the most critical parts of the control algorithms. The paper describes a simulation system to examine a class of control algorithms containing usual industrial robot control (position , revolution and current control) , computed torque technics and decentralized PID controllers, resolved motion acceleration control, hybrid position and force control and fuzzy control. The simulation system consists of a PC/ AT-386, a multitransputer card , graphic monitor and plotter. The software is well structured and only the inverse kinematics depends on the robot type. A separate program running on PC can generate the dynamic model of the robot in symbolic form for nonrecursive computations and has a source-format compatible output to the simulation system. The system to be simulated is decomposed into robot and actuators, control algorithm and sensors. All parts can be prescribed in files containing help by using standard editors. Saturations and time constants of the sensors can be modelled. The transients of select able signals can be stored in files and drawn on screen and plotter by using a separate program. Illustration examples for SCARA type robots are discussed in the paper.
The paper deals with path design and control realization problems of collision avoidance systems ... more The paper deals with path design and control realization problems of collision avoidance systems (CAS) of cars (ground vehicles). CAS emergency path design is based on the principle of elastic band with improved reaction forces for road borders and static obstacles allowing quick computation of the force equilibrium. The CAS path (reference signal) is smoothed and realized using receding horizon control (RHC). The car can be modelled by full (non-affine) or simplified (input affine) nonlinear models. The nonlinear predictive control problem is solved by using time varying linearization along appropriately chosen nominal control and state sequences, and analytical solution of the minimization of a quadratic criterion satisfying endconstraint. Differential geometric approach (DGA), known from control literature for the input affine nonlinear model, has been used for control initialization in the first horizon. For state estimation Kalman filters and measurements of two antenna GPS and Inertial Navigation System (INS) are used. A stand-alone software has been been developed using the C Compiler of MATLAB R2006a satisfying real time expectations.
We address the motion planning problem (open-loop trajectory design) for manipulating rigid bodie... more We address the motion planning problem (open-loop trajectory design) for manipulating rigid bodies with permanent rolling contact without slipping. This problem is related in particular to dextrous manipulation with robotic hands, consisting in changing the position and orientation of the manipulated object together with its grasp. We prove the flatness property for planar structures allowing to solve the motion planning problem by simple interpolation, without need to integrate the system differential equations and without quasi-static approximations. Though this property fails to be valid for general three-dimensional hand structures, similar results can be obtained for special structures thanks to the notion of Liouvillian systems. The links between flat or Liouvillian handobject structures and non-holonomy of the contacts between fingers and object are also discussed. Several examples are studied in details.
The primary scope of the paper lies on the identification of an aircraft's nonlinear dynamic ... more The primary scope of the paper lies on the identification of an aircraft's nonlinear dynamic model. It is assumed that the aircraft has no inbuilt navigational system, nor any sensors mounted on its control surfaces. The flight of the airplane is influenced by the control column and pedals manipulated by the pilot whose positions can only visually be observed. This situation can often occur in the first phase of control system development of airplanes. Hence, for the time of data logging, an external sensory system (GPS, IMU) and a camera system were deployed on the airplane supporting the collection of flight data for state estimation and model identification. An earlier paper discussed the computation of the actuator signals thus the paper deals mainly with the state estimation and model identification. State estimation is based on two-level Extended Kalman Filters with additional correction in an external loop. System identification is based on the dynamical equations of rigid body with additional weighted nonlinear terms for 3D forces and torques. Wind effects are taken into consideration. From the inertial parameters only the mass is known. Dominating nonlinear functions in the force and torque model are selected by using hypotheses tests. The results are presented for a real sailplane using flight data.
The paper deals with the identification of the system parameters in the nonlinear dynamic model o... more The paper deals with the identification of the system parameters in the nonlinear dynamic model of fixed wing UAVs. Fixed wings airplanes are popular in long distance applications and have to be modelled accurately to guarantee efficient control properties. Different methods are suggested to solve the parameter estimation beginning with the standard linear regression (LR) and continued with its extension (ELR), the optimization using interior point methods and finally using the FireFly technique, which is a metaheuristic algorithm. The methods illustrate the convergence and the speed of these approaches. The known default parrameter values of a Sekwa UAV were used to demonstrate that the elaborated identification methods can also reconstruct the numerical values of the dimensionless system parameters embedded into the nonlinear model using the physical weighting functions. After the extension of linear regression, MinMax optimization algorithm was used to get the best and optimal solution and reconstruct the parameters of the Sekwa aircraft. FireFly optimization gives also comparable results with minmax method. Flight data was needed for simulation and testing the different approaches. Matlab and toolboxes were used as simulation software. The results showed the estimated parameters are more accurate than linear regression estimation. Even though it is a small improvment this will reflect in all calculations.
This paper presents two object manipulation planning methods based on fitted stratified and semi-... more This paper presents two object manipulation planning methods based on fitted stratified and semi-stratified approaches using finger relocations. The problem is discussed in the framework of a motion planning problem. The goal of the methods is to steer an object from an initial configuration to a final configuration while it is possible to reposition the fingertips on the surface in a predefined way. We assume there is no rolling and sliding but finger relocations are allowed. The first technique follows a pure stratified approach, however unlike the previously published method, the exact kinematic model of the manipulation system is matched with a virtual model masking the behavior of the original system. This provides a simpler model than the earlier stratified method by reducing the generally hard symbolic computation problem to a simple (almost pure numerical) one. The paper also introduces a semi-stratified manipulation
This paper addresses new algorithms for motion planning of walking robots if they are given by st... more This paper addresses new algorithms for motion planning of walking robots if they are given by stratified holonomic and nonholonomic kinematic models. The mathematical details for general stratified systems are investigated in [1], [2], [3], [4]. The main motivation of our concept is to complete motion planning algorithms that are able to avoid obstacles in the configuration space of walking robots. The proposed methods achieve this goal by leading the robot along a decomposed reference trajectory. Although the reference trajectory should still be restricted, it can be used to obstacle avoidance. The algorithms are demonstrated on an illustrative example of the hexapod robot.
Abstract—The paper introduces a new model to describe the friction phenomenon at low velocities. ... more Abstract—The paper introduces a new model to describe the friction phenomenon at low velocities. The model has the useful property that it is linear in parameters. Using this model robust adaptive control algorithm is developed for high precision positioning. Simulations were performed to show the performances of the applied control algorithm. Keywords—Friction modelling, Friction Compensation, Robust Adaptive Control.
The paper presents a control algorithm for high precision position tracking of the DC motor drive... more The paper presents a control algorithm for high precision position tracking of the DC motor driven mechatronic systems near Striebeck velocities. The algorithm is based on a linearized friction model, which is introduced in the control algorithm and its aim is to compensate the effect of nonlinear friction force. An identification method, to obtain the parameters of the linearized friction model is also presented. Experimental measurements are provided to show the performances of the proposed control algorithm.
IEEE Transactions on Control Systems and Technology, Sep 1, 2015
Many applications require fast control action and efficient constraint handling, such as in aircr... more Many applications require fast control action and efficient constraint handling, such as in aircraft or vehicle control, where instead of the slow online computation of the model predictive control (MPC) the explicit MPC can be an alternative solution. Explicit MPC controllers consist of several affine feedback gains, each of them valid over a polyhedral region of the state space. The exponential blow-up of the number of regions with increasing the prediction horizon increases the searching time among the regions extremely which together with the requirement of the full state measurement decreases its applicability for real systems. First, discrete-time actual Kalman filter is designed for the semiactive suspension and applied to explicit MPC controller that requires only measurement of the suspension deflection. Second, this paper presents a systematic way to design Gaussian radial basis function-based neural network (NN) approximation of the explicit MPC controller and shows that a well-tuned NN with some neurons can replace the explicit MPC controller. This nonlinear state-feedback controller can ensure the fast control action but price of the approximation is some deterioration of the performance value. The complete novel nonlinear control system with Kalman filter is analyzed in detail. The derived controllers are evaluated through simulations, where shock tests and white noise velocity disturbances are applied to a real quarter car vertical model.
Received 2012-06-25, revised 2012-10-11, accepted 2012-10-12 The primary scope of this study lays... more Received 2012-06-25, revised 2012-10-11, accepted 2012-10-12 The primary scope of this study lays on system technique so-lutions of collecting data required for the identification of an aircraft’s nonlinear dynamic model. It is assumed that the aircraft has no inbuilt navigational sys-tem, nor any sensors mounted on its control surfaces. The con-trol column and pedals manipulated by the pilot can only visu-ally be observed. For the time of data logging, an external sen-sory system (GPS, IMU) and a camera system were deployed on the airplane supporting the collection of flight data. The paper presents the data acquisition solutions required for aircraft’s nonlinear model identification, with an emphasis on the determination of the control surface positions as the sys-tem’s input signals using image processing. During flight, the control column and pedal positions manipulated by the pilot are recorded using a video camera and with post processing, data is converted to control surface ...
Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepe... more Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepezik a biztonsagos erőművi es folyamatiranyitasi rendszereknek, robotizalt gyartorendszereknek es az autonom foldi, legi, vizi es űrbeli jarművek iranyitasi rendszereinek. A harom kotetre tervezett sorozat eme utolso kotete a robusztus iranyitasok elmeletevel es tervezesevel foglalkozik. Szerves folytatasa az altalanos rendszertechnikai ismereteket ado első kotetnek es a tobbvaltozos optimalis, nemlinearis es adaptiv szabalyozasok korszerű tervezesi modszereit bemutato masodik kotetnek. A robusztus iranyitasok elmelete arra a kerdesre keres mernoki valaszt, hogyan lehet olyan fix, a tervezes es implementalas utan uzem kozben mar nem valtozo szabalyozot tervezni, amely valtozo szabalyozott szakaszok eseten is biztositani tudja a szabalyozassal szemben tamasztott elvarasok (stabilitas, zavaras elnyomas, kis dinamikus es statikus hiba) teljesuleset. A kotet előszor osszefoglalja a tervezeshez szukseges matematikai alapokat. Az idő- es frekvenciatartomanybeli jelek nagysaganak jellemzesere normakat definial, es bevezeti a targyalasukhoz szukseges Lebesgue- es Hardy-tereket. Megfogalmazza a belső stabilitas elvet es perturbaciok esetere a kis erősites tetelt. Bemutatja a stabilizalo szabalyozok Youla-parameterezeset. A perturbalt rendszer leirasara bevezeti a linearis tort transzformaciokat (LFT). Megadja a stabilizalo szabalyozok allapotteres alakjat. A tervezesi modszerek kozul előszor a linearis rendszer kvadratikus kriterium szerinti optimalis iranyitasaval foglalkozik LTV, LTI es sztochasztikus rendszer eseten. Modszert mutat be a nagy fazistobbletet biztosito hurokatvitel visszaallitasra. Megfogalmazza az altalanos H2 (energia) optimalis szabalyozotervezesi feladatot es megadja az optimalis iranyitas szamitasi modszeret. Ezutan a Hinf optimalis szabalyozas tervezesere mutat be modszereket. Megadja a gamma-optimalis centralis Hinf szabalyozo tervezesi algoritmusat, az integralo szabalyozas biztositasat es a telites kezeleset. Ket megoldast (1-DOF, 2-DOF) mutat be a hurokformalas tervezesere, utobbiban lehetőseget adva referencia modell előirasara is. Az eredmenyeket repulőgep iranyitas eseten illusztralja. Modszert mutat be a Hinf szabalyozo tervezesere mu-analizis, DK-iteracio es LMI technika bevonasaval, melyet az invertalt inga instabil munkapontja koruli szabalyozassal illusztral. Ezutan a kotet bemutatja a nemsima, nemkonvex optimalizalason alapulo előirhato fokszamu es stabil Hinf robusztus szabalyozo tervezesi modszereket es a tervezest tamogato szoftver eszkozoket. A tervezesi modszer lehetőve teszi megvalaszthato fokszamu mintaveteles Hinf szabalyozo es előirt strukturaju analog (pl. MIMO PID) szabalyozok tervezeset, valamint kozos Hinf szabalyozo tervezeset egyszerre tobb szabalyozott szakaszhoz. Pelda mutatja be az optimalizalast az ujabb MATLAB eszkozok bevonasaval is. Vegul a konyv az LPV rendszerek robusztus iranyitasanak bemutatasaval zarul. A modszereket egy pelda illusztralja az ujabb MATLAB eszkozok bevonasaval. A kotet jol hasznosithato az egyetemi szabalyozastechnikai szakiranyu mester- es PhD-kepzesben, es rendszertechnikailag megalapozza a korszerű folyamatiranyitasi, mechatronikai es az autonom (vezető nelkuli) jarműiranyitasi rendszerek tervezeset.
Periodica polytechnica. Electrical engineering and computer science /, Jun 26, 2023
This paper presents the estimation of stability and control derivatives of an unmanned aircraft. ... more This paper presents the estimation of stability and control derivatives of an unmanned aircraft. The aerodynamics are described using regressors composed of velocity, angular rates, flow angles and control surface deflections. The flight data is generated from numerical simulation of postulated equations of motion describing the aerodynamics model. Least squares based on the equation error method is used to estimate the parameters representing the different force and moment aerodynamic coefficients. Statistical analysis is done on the estimates to determine the accuracy and adequacy of the estimates to describe the aerodynamic model. A dynamic simulation based on the identified aerodynamic model is used to improve the parameter estimates through regression of the errors between the flight data and the model response. The aircraft under consideration is a scaled Yak-54 fixed wing unmanned aerial vehicle.
Periodica polytechnica. Electrical engineering and computer science /, May 31, 2022
An estimation model is key in the design and development of an unmanned aerial vehicle's control ... more An estimation model is key in the design and development of an unmanned aerial vehicle's control system. This work presents a complete methodology for modelling the dynamics of a fixed-wing UAV for aerobatic maneuvers. The UAV dynamic non-linear model considered uses total variables instead of a nominal values and perturbation values about certain trimmed conditions for conventional flight envelopes. Such modelling allows the expansion of the flight envelope of an unmanned aerial vehicle to cover the full range of the angle of attack. The quaternion formulation is used since it eliminates the nonlinearity of the aerodynamics due to Euler angles for high angle of attacks. The objective is to have a complete and accurate representation of a highly dynamic fixed wing UAV capable of making aerobatic maneuvers without encountering singularities. A set of controllers are then designed for the inner and outer loops for attitude control using nonlinear dynamic inversion in cascade with a PI controller. Simulations carried out show robust tracking of reference attitude angles.
Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepe... more Az iranyitastechnika tudomanya rohamosan fejlődik, eredmenyei ma mar elengedhetetlen alapjat kepezik a biztonsagos erőművi es folyamatiranyitasi rendszereknek, robotizalt gyartorendszereknek es az autonom foldi, legi, vizi es űrbeli jarművek iranyitasi rendszereinek. A harom kotetre tervezett sorozat eme utolso kotete a robusztus iranyitasok elmeletevel es tervezesevel foglalkozik. Szerves folytatasa az altalanos rendszertechnikai ismereteket ado első kotetnek es a tobbvaltozos optimalis, nemlinearis es adaptiv szabalyozasok korszerű tervezesi modszereit bemutato masodik kotetnek. A robusztus iranyitasok elmelete arra a kerdesre keres mernoki valaszt, hogyan lehet olyan fix, a tervezes es implementalas utan uzem kozben mar nem valtozo szabalyozot tervezni, amely valtozo szabalyozott szakaszok eseten is biztositani tudja a szabalyozassal szemben tamasztott elvarasok (stabilitas, zavaras elnyomas, kis dinamikus es statikus hiba) teljesuleset. A kotet előszor osszefoglalja a tervezeshez szukseges matematikai alapokat. Az idő- es frekvenciatartomanybeli jelek nagysaganak jellemzesere normakat definial, es bevezeti a targyalasukhoz szukseges Lebesgue- es Hardy-tereket. Megfogalmazza a belső stabilitas elvet es perturbaciok esetere a kis erősites tetelt. Bemutatja a stabilizalo szabalyozok Youla-parameterezeset. A perturbalt rendszer leirasara bevezeti a linearis tort transzformaciokat (LFT). Megadja a stabilizalo szabalyozok allapotteres alakjat. A tervezesi modszerek kozul előszor a linearis rendszer kvadratikus kriterium szerinti optimalis iranyitasaval foglalkozik LTV, LTI es sztochasztikus rendszer eseten. Modszert mutat be a nagy fazistobbletet biztosito hurokatvitel visszaallitasra. Megfogalmazza az altalanos H2 (energia) optimalis szabalyozotervezesi feladatot es megadja az optimalis iranyitas szamitasi modszeret. Ezutan a Hinf optimalis szabalyozas tervezesere mutat be modszereket. Megadja a gamma-optimalis centralis Hinf szabalyozo tervezesi algoritmusat, az integralo szabalyozas biztositasat es a telites kezeleset. Ket megoldast (1-DOF, 2-DOF) mutat be a hurokformalas tervezesere, utobbiban lehetőseget adva referencia modell előirasara is. Az eredmenyeket repulőgep iranyitas eseten illusztralja. Modszert mutat be a Hinf szabalyozo tervezesere mu-analizis, DK-iteracio es LMI technika bevonasaval, melyet az invertalt inga instabil munkapontja koruli szabalyozassal illusztral. Ezutan a kotet bemutatja a nemsima, nemkonvex optimalizalason alapulo előirhato fokszamu es stabil Hinf robusztus szabalyozo tervezesi modszereket es a tervezest tamogato szoftver eszkozoket. A tervezesi modszer lehetőve teszi megvalaszthato fokszamu mintaveteles Hinf szabalyozo es előirt strukturaju analog (pl. MIMO PID) szabalyozok tervezeset, valamint kozos Hinf szabalyozo tervezeset egyszerre tobb szabalyozott szakaszhoz. Pelda mutatja be az optimalizalast az ujabb MATLAB eszkozok bevonasaval is. Vegul a konyv az LPV rendszerek robusztus iranyitasanak bemutatasaval zarul. A modszereket egy pelda illusztralja az ujabb MATLAB eszkozok bevonasaval. A kotet jol hasznosithato az egyetemi szabalyozastechnikai szakiranyu mester- es PhD-kepzesben, es rendszertechnikailag megalapozza a korszerű folyamatiranyitasi, mechatronikai es az autonom (vezető nelkuli) jarműiranyitasi rendszerek tervezeset.
Third-generation robotic systems are intelligent in the sense that they can perform a large reper... more Third-generation robotic systems are intelligent in the sense that they can perform a large repertory of complex tasks under conditions not known a priori. They are usually sensor-coupled using multisensory (vision, force, tactiie, etc.) information about their initial state and environment, have decision-making capabilities, can monitor and modify their plans learning from past experience. They have the properties of flexibility and artificial intelligence. The aim of the book was to provide wide coverage of these concepts based on the latest developments of well-known experts working in academic and research institutions. The book is addressed to scientists, engineers, postgraduate students and professionals working or having interest in intelligent robotics and control. The book is divided in 5 parts containing 18 chapters. Part I is devoted to introductory issues and it consists of Chapter 1: Introduction to Intelligent Robotic Systems written by Tzafestas (National Technical University of Athens,. Greece). The general architecture of intelligent robotic control (consisting of organization, coordination and execution levels), the basic problems of robot modeling and motion control, and the classification of sensors including vision are introduced. Three examples of intelligen t robotic systems are selected from the field of sensor-based (Espirit 278 and Pardue system) and mobile (KAMRO) robots. Part II deals with the structure and programming of intelligent robotic systems. Chapter 2: Theory and Design of Intelligent Robotic Systems by Valavanis (Northeastern University, Boston, Massachusetts), presents a general theory of intelligent machines and robotic systems based on a heuristic probabilistic model and entropy functions to describe the system performance of structures composed of organization, coordination and execution levels. Chapter 3: Hierarchy oj Intelligent On-Line Execution by Kelley (Rensselaer Polytechnic Institute, Troy, New York) deals with a robotic assembly system that allows both automatic programming and execution despite uncertainties in the task environment. The principle ofleast commitment is followed, and the system is partitioned into off-line (planners, specialists) and on-line (supervisor, specialists, interfaces) modules. Some details are given for the design of the supervisor and its implementation with 4 specialists on VAX running under Unix. Chapter 4: Skill-Based Expert Systems in Robotics by Tomovic (University of Belgrade, Yugoslavia), deals with the skill level (functional motion of human extremities) of a hierarchical control structure using both numerical and non numerical models. It concentrates on multifinger robot hands and describes the hand mechanics, sensors and local controllers of the Belgrade-USC Hand, and the multilevel manipulator control using computer vision and expert system (for preshaping, grasping mode, etc.
Journal of Advanced Computational Intelligence and Intelligent Informatics, Nov 20, 2007
This paper addresses the predictive control of the harmonic drive in an automotive application. T... more This paper addresses the predictive control of the harmonic drive in an automotive application. The goal of the control was to provide good steering feel for the driver and satisfactory tracking performance in a steering system. The paper presents the dynamic model of the harmonic drive, a design framework and a two step algorithm for predictive controller design. The elaborated model predictive controller is similar to a cascade type controller with constraints in the performance function to ensure closed loop stability and a useful compromise between torque tracking and position tracking. The controller was developed and implemented in a real-time environment for rapid prototype design using Matlab, Simulink, Real-Time Workshop and dSPACE AutoBox hardware, then it was experimentally tuned for best steering feel and good tracking performance.
Simulation tools can support robot control design and help to find the most critical parts of the... more Simulation tools can support robot control design and help to find the most critical parts of the control algorithms. The paper describes a simulation system to examine a class of control algorithms containing usual industrial robot control (position , revolution and current control) , computed torque technics and decentralized PID controllers, resolved motion acceleration control, hybrid position and force control and fuzzy control. The simulation system consists of a PC/ AT-386, a multitransputer card , graphic monitor and plotter. The software is well structured and only the inverse kinematics depends on the robot type. A separate program running on PC can generate the dynamic model of the robot in symbolic form for nonrecursive computations and has a source-format compatible output to the simulation system. The system to be simulated is decomposed into robot and actuators, control algorithm and sensors. All parts can be prescribed in files containing help by using standard editors. Saturations and time constants of the sensors can be modelled. The transients of select able signals can be stored in files and drawn on screen and plotter by using a separate program. Illustration examples for SCARA type robots are discussed in the paper.
The paper deals with path design and control realization problems of collision avoidance systems ... more The paper deals with path design and control realization problems of collision avoidance systems (CAS) of cars (ground vehicles). CAS emergency path design is based on the principle of elastic band with improved reaction forces for road borders and static obstacles allowing quick computation of the force equilibrium. The CAS path (reference signal) is smoothed and realized using receding horizon control (RHC). The car can be modelled by full (non-affine) or simplified (input affine) nonlinear models. The nonlinear predictive control problem is solved by using time varying linearization along appropriately chosen nominal control and state sequences, and analytical solution of the minimization of a quadratic criterion satisfying endconstraint. Differential geometric approach (DGA), known from control literature for the input affine nonlinear model, has been used for control initialization in the first horizon. For state estimation Kalman filters and measurements of two antenna GPS and Inertial Navigation System (INS) are used. A stand-alone software has been been developed using the C Compiler of MATLAB R2006a satisfying real time expectations.
We address the motion planning problem (open-loop trajectory design) for manipulating rigid bodie... more We address the motion planning problem (open-loop trajectory design) for manipulating rigid bodies with permanent rolling contact without slipping. This problem is related in particular to dextrous manipulation with robotic hands, consisting in changing the position and orientation of the manipulated object together with its grasp. We prove the flatness property for planar structures allowing to solve the motion planning problem by simple interpolation, without need to integrate the system differential equations and without quasi-static approximations. Though this property fails to be valid for general three-dimensional hand structures, similar results can be obtained for special structures thanks to the notion of Liouvillian systems. The links between flat or Liouvillian handobject structures and non-holonomy of the contacts between fingers and object are also discussed. Several examples are studied in details.
The primary scope of the paper lies on the identification of an aircraft's nonlinear dynamic ... more The primary scope of the paper lies on the identification of an aircraft's nonlinear dynamic model. It is assumed that the aircraft has no inbuilt navigational system, nor any sensors mounted on its control surfaces. The flight of the airplane is influenced by the control column and pedals manipulated by the pilot whose positions can only visually be observed. This situation can often occur in the first phase of control system development of airplanes. Hence, for the time of data logging, an external sensory system (GPS, IMU) and a camera system were deployed on the airplane supporting the collection of flight data for state estimation and model identification. An earlier paper discussed the computation of the actuator signals thus the paper deals mainly with the state estimation and model identification. State estimation is based on two-level Extended Kalman Filters with additional correction in an external loop. System identification is based on the dynamical equations of rigid body with additional weighted nonlinear terms for 3D forces and torques. Wind effects are taken into consideration. From the inertial parameters only the mass is known. Dominating nonlinear functions in the force and torque model are selected by using hypotheses tests. The results are presented for a real sailplane using flight data.
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Papers by Béla Lantos