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EN
The paper presents an adaptive control algorithm for an asymmetric quadcopter. For determining the control algorithm, the identification was made, and an identification algorithm is presented in the form of a recursive method. The control method is realized using inverse dynamics, full state feedback and finally adaptive control method. The algorithms for the off-line and on-line identification of quadcopter model parameters are also presented. The paper shows the effectiveness of the selected algorithm on the example of the movement along a given trajectory. Finally, recommendations of the application of these different methods are made.
PL
W pracy przedstawiono algorytm sterowania adaptacyjnego dla asymetrycznego quadrocoptera. W celu określenia sterowania zrealizowano identyfikację parametrów i przedstawiono algorytm identyfikacji w formie metody rekurencyjnej. Metoda sterowania realizowana jest z wykorzystaniem dynamiki odwrotnej, przesuwania biegunów oraz sterowania adaptacyjnego. Zaprezentowano algorytmy identyfikacji parametrów modelu quadrocoptera w trybie off-line i on-line. W artykule przedstawiono skuteczność wybranych algorytmów na przykładzie ruchu wzdłuż podanej trajektorii. Na zakończenie artykułu przedstawiono zalecenia dotyczące stosowania różnych metod sterowania.
EN
To solve the nonlinear control problems of the unknown time-varying environmental disturbances and parametric uncertainties for ship course-keeping control, this paper presents an adaptive self-regulation PID (APID) scheme which can ensure the boundedness of all signals in the ship course-keeping control system by using the Lyapunov direct method. Compared with the traditional PID control scheme, the APID control scheme not only is independent of the model parameters and the unknown input, but also can regulate the gain of PID adaptively and resist time-varying disturbances well. Simulation results illustrate the effectiveness and the robustness of the proposed control scheme.
EN
In this paper, the issue related to control of the plant with nonconstant parameters is addressed. In order to assure the unchanged response of the system, an adaptive state feedback speed controller for permanent magnet synchronous motor is proposed. The model-reference adaptive system is applied while the Widrow-Hoff rule is used as adjustment mechanism of controller’s coefficients. Necessary modifications related to construction of the cost function and formulas responsible for adjustment of state feedback speed controller’s coefficients are depicted. The impact of adaptation gain, which is the only parameter in proposed adjustment mechanism, on system behaviour is experimentally examined. The discussion about computational resources consumption of the proposed adaptation algorithm and implementation issues is included. The proposed approach is utilized in numerous experimental tests on modern SiC based drive with nonconstant moment of inertia. Comparison between adaptive and nonadaptive control schemes is also shown.
EN
The paper describes a nonlinear controller design technique applied to a servo drive in the presence of hard state constraints. The approach presented is based on nonlinear state-space transformation and adaptive backstepping. It allows us to impose hard constraints on the state variables directly and to achieve asymptotic tracking of any reference trajectory inside the constraints, despite unknown plant parameters. Two control schemes (with and without integral action) are derived, investigated and then compared. Several examples demonstrate the main features of the design procedure and prove that it may be applied in case of motion control problems in electric drive automation.
EN
The paper presents a method for designing a neural speed controller with use of Reinforcement Learning method. The controlled object is an electric drive with a synchronous motor with permanent magnets, having a complex mechanical structure and changeable parameters. Several research cases of the control system with a neural controller are presented, focusing on the change of object parameters. Also, the influence of the system critic behaviour is researched, where the critic is a function of control error and energy cost. It ensures long term performance stability without the need of switching off the adaptation algorithm. Numerous simulation tests were carried out and confirmed on a real stand.
EN
This paper deals with two control algorithms which utilize learning of their models’ parameters. An adaptive and artificial neural network control techniques are described and compared. Both control algorithms are implemented in MATLAB and Simulink environment, and they are used in the simulation of a postion control of the LWR 4+ manipulator subjected to unknown disturbances. The results, showing the better performance of the artificial neural network controller, are shown. Advantages and disadvantages of both controllers are discussed. The usefulness of the learning algorithms for the control of LWR 4+ robots is discussed. Preliminary experiments dealing with dynamic properties of the two LWR 4+ robots are reported.
EN
This paper analyses the management process of the vessel traffic control on one-way section on navigable canal with the adaptive time-sequential filter (traffic lights). One-way section on canal significantly decreases waterway capacity and requests special attention in control and regulation of the vessel traffic. The vessel traffic is a stochastic variable, and the vessel traffic control needs to be flexible and adaptive in order to achieve the required traffic flow with minimal delays. On the one-way section, two independent variable vessel flows from opposite directions are encountered, and fixed (predefined) signal plans lead to an increase in vessel delays. An appropriate solution is development of a Fuzzy Control System (FCS) for the vessel traffic control. A control algorithm is designed according to a set of linguistic rules that describes input parameters for the control strategy. The estimated and approximate input parameters are implemented in the algorithm as fuzzy sets. The final result of the developed algorithm is the traffic light scheme (duration of green light for certain direction). The presented control system can be used as an adaptive automatic control system for the vessel traffic control processes on navigable canals or on critical sections of other waterways.
EN
Today's highly automated manufacturing specifies the service time of a tool in a way that the tooling costs are balanced against the potential costs of a tool failure. However, the potential cost induced by a tool malfunctioning are rather high. Therefore, the current state-of-the art tackles this issue by replacing the tools prematurely at fixed intervals. To tap into the potential of under-utilized tool runtime this work purposes the use of sensory-tool holders and an interfering feedback loop to the machine tool control system. Besides its real-time closed loop control, to avoid tool failure, it also provides data in the context of (a) the work order, (b) the produced part, (c) the NC-block and command line, on (d) specific machines. Based on this data an ex-post analysis to optimize tool-life and productivity scenarios becomes possible, e.g. custom NC-programs for certain work-orders, configurations and machines. Furthermore, downstreamed work steps can be changed e.g. only to measure produced workpieces if abnormal vibrations are reported by in-process-monitoring.
EN
The issue addressed in the article concerns the current needs and possibilities of computer-aided design of adaptive control strategies in machining processes. A simulative method of selecting the adaptive feed control strategy while rough turning materials difficult to machine, effective and inexpensive in its implementation, based on controlling the load placed on the machine's drives, has been presented. The results of a number of virtual tests of the proposed feed control strategy have been included, while paying particular attention to the stability of the machining process during moments of sudden change in the machining allowance. The obtained results meet the accepted quality indicators of the control algorithm. At the same time, the experiences collected by the author while conducting the tests confirmed the complexity of the issue and the resulting necessity to implement a comprehensive simulation testing program.
EN
We introduce a control strategy to solve the regulation control problem, from the perspective of trajectory planning, for an uncertain 3D overhead crane. The proposed solution was developed based on an adaptive control approach that takes advantage of the passivity properties found in this kind of systems. We use a trajectory planning approach to preserve the accelerations and velocities inside of realistic ranges, to maintaining the payload movements as close as possible to the origin. To this end, we carefully chose a suitable S-curve based on the Bezier spline, which allows us to efficiently handle the load translation problem, considerably reducing the load oscillations. To perform the convergence analysis, we applied the traditional Lyapunov theory, together with Barbalat’s lemma. We assess the effectiveness of our control strategy with convincing numerical simulations.
EN
Torsional vibrations induced in drilling systems are detrimental to the condition of the machine and to the effectiveness of the engineering process. The cause of vibrations is a nonlinear and unknown friction between a drill string and the environment, containing jumps in its characteristics. Nonlinear behaviour of the friction coefficient results in self-excited vibration and causes undesirable stick-slip oscillations. The aim of this paper is to present a novel adaptive technique of controlling vibrating systems. The scheme is based on the linear quadratic regulator and uses direct measurements of the friction torque to synthesize its linear dynamic approximation. This approach allows generating a control law that takes into account the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The controller’s performance is examined via numerical simulations of the stabilization of the drilling system. The proposed solution outperforms the comparative LQG regulator in terms of the minimization of the assumed cost functional and the overall stability of the control system under the nonlinear disturbance.
EN
The genesis of both coherent structures and reactive flow control strategies is explored. Futuristic control systems that utilize microsensors and microactuators together with artificial intelligence to target specific coherent structures in a transitional or turbulent flow are considered. Of possible interest to the readers of this journal is the concept of smart wings, to be briefly discussed early in the article.
EN
This work describes a new study to achieve a combination of modified function projective synchronization between three different chaotic systems through adaptive control. Using the Lyapunov function theory, the asymptotic stability of the error dynamics is obtained and discussed. Further, we set some appropriate initial conditions for the state variables and assigning specific values to the parameters and obtain the graphical results, which shows the efficiencies of the new method. Finally, we summarized our work with conclusion and references.
EN
We study an elegant snap system with only one nonlinear term, which is a quadratic nonlinearity. The snap system displays chaotic attractors, which are controlled easily by changing a system parameter. By using analysis, simulations and a real circuit, the dynamics of such a snap system has been investigated. We also investigate backstepping based adaptive control schemes for the new snap system with unknown parameters.
EN
Passive noise reduction methods require thick and heavy barriers to be effective for low frequencies and those clasical ones are thus not suitable for reduction of low frequency noise generated by devices. Active noise-cancelling casings, where casing walls vibrations are actively controlled, are an interesting alternative that can provide much higher low-frequency noise reduction. Such systems, compared to classical ANC systems, can provide not only local, but also global noise reduction, which is highly expected for most applications. For effective control of casing vibrations a large number of actuators is required. Additionally, a high number of error sensors, usually microphones that measure noise emission from the device, is also required. All actuators have an effect on all error sensors, and the control system must take into account all paths, from each actuator to each error sensor. The Multiple Error FXLMS has very high computational requirements. To reduce it a Switched-Error FXLMS, where only one error signal is used at the given time, have been proposed. This, however, significantly reduces convergence rate. In this paper an algorithm that uses multiple errors at once, but not all, is proposed. The performance of various algorithm variants is compared using simulations with the models obtained from real active-noise cancelling casing.
EN
The paper describes an adaptive control system of the waves, implemented in the Ship Design and Research Centre, CTO S.A. The purpose of generating the waves in the towing tank is the modelling of the environmental conditions during hydrodynamic model tests. The tests are performed on scale models of towed or free running ships, anchored structures like oil rigs or bottommounted structures, e.g. wind turbines. In the towing tank of CTO S.A., the waves are generated using a flap-type wavemaker with hydraulic drive. The adaptive control system includes gain scheduling and Black-Box model. It has been developed and implemented using the 32-bit embedded system and computer application (C#.NET). The Black-Box model was proposed as a simple solution allowing compensating the hydromechanical phenomena affecting the generated waves, i.e. disintegration, reflection, damping and nonlinear energy transfer. The solution proved to be sufficient to generate required wave spectra with expected accuracy in a user-friendly manner.
PL
Artykuł opisuje adaptacyjny system sterowania falami basenowymi, który został wdrożony w Centrum Techniki Okrętowej (CTO) S.A. Fale są generowane w głębokowodnym basenie holowniczym podczas testów modelowych w celu odwzorowania warunków oddziaływania środowiska morskiego. Testy są przeprowadzane na modelach holowanych lub pływających swobodnie (statki), zakotwiczonych (platformy) lub przymocowanych trwale do dna (turbiny wiatrowe). W głębokowodnym basenie holowniczym CTO S.A., fale generowane są przez płytowy wywoływacz fal z płytą mocowaną powyżej dna basenu i z napędem hydraulicznym. Adaptacyjne sterowanie falą basenową obejmuje harmonogramowanie wzmocnienia i model typu Black-Box. Opracowany system sterowania został implementowany w 32-bitowym systemie wbudowanym i aplikacji komputerowej w języku C# w środowisku .NET. Wprowadzony model typu Black-Box uwzględnia efekty hydromechanicznych procesów i zjawisk – m. in. rozpadu, odbicia, tłumienia i nieliniowego transferu energii – które mają wpływ na generowane fale. Przedstawione rozwiązanie pozwala w prosty sposób i z oczekiwaną dokładnością modelować zadane widma fal basenowych.
EN
Cogeneration of electric energy and heat as well as seasonal changes of the condenser pressure in low-pressure extraction/condensing turbines require adaptive control to adapt the geometry of the blading system to the changing flow conditions. In this paper adaptive control is achieved by means of restaggering (rotating) adjustable stator blades. An increase of turbine efficiency and power coming from adaptive control is numerically estimated for a group of two exit stages of an extraction/condensing turbine of power 60 MW. The calculations are made with the help of a computer code FlowER – a 3D solver of turbomachinery flows based on Reynolds-averaged Navier-Stokes equations for perfect gas.
PL
W artykule dokonano przeglądu rozwiązań systemów wizyjnych na stanowiskach zrobotyzowanych. Zaprezentowano urządzenia wchodzące w skład takiego systemu. Dokonano klasyfikacji systemów wizyjnych ze względu na rodzaj rejestrowanego obrazu oraz ze względu na rozmieszczenie kamery lub kamer na stanowisku roboczym. Omówiono możliwości systemów wizyjnych w zależności od konfiguracji sprzętowej. Przedstawiono przebieg procesu wizyjnego rozpoczynając od akwizycji obrazu. Omówiono stosowane metody przetwarzania i analizy obrazu pochodzącego z kamer systemu wizyjnego. Pokazano także przykładowe aplikacje zrealizowane z wykorzystaniem systemów wizyjnych.
EN
The article presents an issue related to the use of vision systems at robotic stands. Devices included in such a system have been presented. The classification of vision systems was made due to the type of image being recorded and due to the location of the camera or cameras at the workstation. The capabilities of vision systems are discussed depending on the hardware configuration. The course of the video process was presented starting from image acquisition. The methods of image processing and analysis originating from video camera cameras are discussed. Also shown are examples of applications implemented using vision systems.
PL
W artykule opisano sterowanie układem napędowym z połączeniem sprężystym, pętla regulacji prędkości została zaprojektowana w oparciu o dwa modele neuronowe. Jeden z nich stanowi główny regulator, natomiast drugi jest modelem odniesienia wykorzystywanym w trakcie obliczeń. Adaptacja wag sieci neuronowych jest realizowana on-line. Artykuł zawiera opis teoretyczny zaimplementowanej struktury, a także badania symulacyjne oraz eksperymentalne zrealizowane z wykorzystaniem procesora sygnałowego karty dSPACE1103.
EN
Paper presents control system applied for electrical drive with elastic connections. Speed control loop of the whole structure is based on two neural models. One of them is applied as the main controller, the second is the internal model of the plant used for calculations of control signal. Adaptation of weights in neural networks is done in on-line mode. Article contains theoretical description of implemented control structure, simulation tests as well as experimental tests using digital signal processor of dSPACE1103.
20
Content available remote Adaptive control of two-mass drive system with nonlinear stiffness
EN
The paper describes a nonlinear controller design technique for a servo drive in the presence of nonlinear friction together with a flexible shaft connecting the motor and the load. The shaft is characterized by the nonlinear stiffness curve. Two different type of the nonlinear stiffness curve are considered. The proposed controller is based on adaptive backstepping, modified by the use of command filtering. The proposed approach allows to accomplish the rigorous proof of the closed-loop system stability. Several experiments prove the control effectiveness.
PL
Opisano problem sterowania prędkością układu napędowego z nieliniowym tarciem, połączeniem sprężystym i nieznanymi parametrami. Elastyczne połączenie jest opisane przy pomocy nieliniowej funkcji sztywności. Rozważane są dwa typy nieliniowej funkcji sztywności: wypukła i wklęsła. Układy regulacji są projektowane przy pomocy metod „adaptive backstepping” z filtracją wartości zadanych. Opisano szereg eksperymentów, które ilustrują charakterystyczne właściwości układu regulacji.
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