LMI based antiswing adaptive controller for uncertain overhead cranes

This paper proposes an adaptive anti-sway controller for uncertain overhead cranes. The state-space model of the 2D overhead crane with the system parameter uncertainties is shown firstly. Next, the adaptive controller which can adapt with the system uncertainties and input disturbances is established. The proposed controller has ability to move the trolley to the destination in short time and with small oscillation of the load despite the effect of the uncertainties and disturbances. Moreover, the controller has simple structure so it is easy to execute. Also, the stability of the closed-loop system is analytically proven. The proposed algorithm is verified by using Matlab/Simulink simulation tool. The simulation results show that the presented controller gives better performances (i.e., fast transient response, position tracking, and low swing angle) than the state feedback controller when there exist system parameter variations as well as input disturbances

Adaptive fuzzy observer based hierarchical sliding mode control for uncertain 2D overhead cranes

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This paper proposes a new approach to robustly control a 2D under-actuated overhead crane system, where a payload is effectively transported to a destination in real time with small sway angles, given its inherent uncertainties such as actuator nonlinearities and external disturbances. The control law is proposed to be developed by the use of the robust hierarchical sliding mode control (HSMC) structure in which a second-level sliding surface is formulated by two first-level sliding surfaces drawn on both actuated and under-actuated outputs of the crane. The unknown and uncertain parameters of the proposed control scheme are then adaptively estimated by the fuzzy observer (FO), where the adaptation mechanism is derived from the Lyapunov theory. More importantly, stability of the proposed strategy is theoretically proved. Effectiveness of the proposed adaptive FO-based HSMC approach was extensively validated by implementing the algorithm in both synthetic simulations and real-life experiments, where the results obtained by our method are highly promising

Sliding mode robot controller parameter tuning with genetic algorithms and fuzzy logic

Sliding Mode Controllers (SMC) possess robustness properties under parameter uncertainties. Usually, a Lyapunov based controller design with a switching control signal constitutes the backbone of robustness. However, the ideally zero switching time of the controller output cannot be achieved in digital implementation. This causes a phenomenon called chattering – high frequency oscillations observed in systems state variables. Chattering also shows itself as high amplitude oscillatory behavior in the control signal. A chattering actuator output is not favorable for many plants, including robot manipulators driven by actuator torques. This problem is traditionally solved by smoothing the switching control output, deviating from the original mathematical foundations robustness. Over-smoothing causes performance deterioration, while too limited smoothing action may lead to the wear of the mechanical system components. This motivates the exploration of automatic tuning approaches which consider chattering and performance simultaneously. This thesis proposes two SMC smoothing and parameter tuning methods with soft computing (SC) methodologies. The first method is based on Genetic Algorithms (GA). SMC controller parameters, including the ones governing the smoothing action are tuned off-line by evolutionary computing. A measure is employed to assess the instantaneous level of chattering. The integral of this value combined with performance indicators including the rise time and steady state error in a step reference scenario are used as the fitness function. The method is tested on the model of a direct drive (DD) SCARA type robot, via simulations. The GA-tuned SMC is, however, tailored for a fixed reference signal and fixed payload. Different references and payload values may pronounce the chattering effects or lead to performance loss due to over-smoothing. The second SMC parameter tuning method proposed employs a fuzzy logic system to enlarge the applicability range of the controller. The chattering measure and the sliding variable are used as the inputs of this system, which tunes the controller output smoothing mechanism on-line, as opposed to the off-line GA technique. Again, simulations with the direct-drive robot model are employed to test the control and tuning method

Development of the algorithm for energy efficiency improvement of belt conveyor system on open pit mines.

Potrošnja električne energije je u porastu zbog stalne potrebe za poboljšanjem kvaliteta života. Energetska efikasnost je danas jedan od ključnih elementa u energetskoj politici svih razvijenih zemalja sveta, jer doprinosi unapređenju ekonomije u celini, i produžava vek korišćenja neobnovljivih izvora energije, iz kojih se danas dobija najveći deo električne energije. U mnogim zemljama najveći deo električne energije dobija se iz uglja, npr. u Srbiji je 62% svih kapaciteta za proizvodnju električne energije je u termoelektranama na ugalj, a 65% proizvedene električne energije dobija se iz ovih elektrana. U narednim decenijama težište daljih povećanja kapaciteta za proizvodnju električne energije biće na termoelektranama, što će zahtevati povećanje proizvodnje uglja. Povećani zahtevi za proizvodnjom uglja vode ka povećanju količine uglja i jalovine koju treba transportovati u okviru rudnika sistemom tračnih transportera, zbog čega se povećava njihova dužina i kapacitet, a time i instalisana snaga njihovih pogona. Zbog značajnih snaga pogona i po pravilu 24-časovnog rada od posebnog interesa je unapređenje energetske efikasnosti tračnih transportera. U različitim granama industrije, u kojima se proizvodi ili koristi rastresiti materijal, za transport se koriste različiti tipovi tračnih transportera, sa različitim konstruktivnim i pogonskim karakteristikama. Bez obzira na vrstu i organizaciju površinskog kopa, elektromotorni pogoni na rudarskoj mehanizaciji zbog velikih snaga, složenosti rudarske opreme i vrlo teških uslova rada predstavljaju izazov za primenu savremenih metoda pokretanja i upravljanja, u cilju povećanja efikasnosti rada, kao i energetske efikasnosti. Kod konvencionalnih sistema transportera, rastresiti materijal se transportuje stalnom, nazivnom brzinom. Pri nazivnom kapacitetu sistema površina poprečnog preseka materijala na traci je optimalna (maksimalna), odnosno traka je maksimalno popunjena. Međutim, istraživanja i statističke analize pokazuju da ovakvi sistemi zbog tehnologije kopanja bagera vrlo retko rade sa punim kapacitetom, odnosno da se veliki deo radnog vremena na trakama nalazi manja količina materijala od maksimalno moguće, pa čak i da prazan hod čini značajan deo radnog vremena sistemaElectrical energy consumption is increasing globally in order to keep improving our quality of life. Energy efficiency is today one of the key elements in energy policy of all developed countries in the world, because it contributes to the improvement of economy globally and extends the lifetime of conventional energy sources, since the greatest part of total electrical energy is generated by fossil fuels. In many countries, most electrical energy comes from coal, for example in Serbia, 62% of all capacities for energy production is in thermal power plants which use coal, and they produce 65% of total electrical energy production. In the following decades, the focus will be on thermal power plants to further increase electrical energy capacities, requiring the rise of coal production. The growing demand for coal production leads to increased amounts of coal and overburden to be transported within the mine with belt conveyors systems. The length and the capacity are increasing causing the installed power of these systems to increase. Due to the large power of these drives and existing requirement for continuous operation, 24 hours per day, the improvement of energy efficiency of belt conveyors is naturally of significant interest. In various branches of industry where bulk materials are produced or used, various types of belt conveyors are used for the transport of materials, with different mechanical and drive characteristics. Despite of the type and the organization of the open pit mine, electrical drives on mining machines present a unique challenge to the application of modern techniques of driving and control, due to very large installed power, complexity of mining equipment and demanding environmental conditions, in order to increase the operational and energy efficiency. Conventional systems of conveyors transport bulk material at the constant, rated speed. When the system is at rated capacity, the cross section of material on the belt is at the maximum value, i.e. the belt is fully loaded. However, investigations and statistic analyses show that systems like this, due to technology of excavation very often work at reduced capacity. Most often the instantaneous cross section area of material on the belt is less than the rated value, and even no-load operation makes up a significant part of the system’s operational time

Proceedings - 30. Workshop Computational Intelligence : Berlin, 26. - 27. November 2020

Dieser Tagungsband enthält die Beiträge des 30. Workshops Computational Intelligence. Die Schwerpunkte sind Methoden, Anwendungen und Tools für Fuzzy-Systeme, Künstliche Neuronale Netze, Evolutionäre Algorithmen und Data-Mining-Verfahren sowie der Methodenvergleich anhand von industriellen und Benchmark-Problemen