Upravljačke strukture vibracionog transporta rasutih materijala baziranog na elektromagnetnim aktuatorima

Abstract

REZIME: Primena elektromagnetnog vibracionog pogona u kombinaciji sa energetskim pretvaračem omogućava fleksibilnost vibracionog transporta. Na ovaj način je dobijen vibraciono-transportni sistem, koji se ponaša kao kontrolisani mehanički oscilator. Regulisani rezonantni elektromagnetni transporteri dodatno obezbeđuju visoku energetsku efikasnost koja se ogleda u minimalnoj vrednosti pobudne struje kalema vibracionog aktuatora, minimalnoj potrošnji električne energije i poboljšanju faktora snage celokupnog elektromagnetnog pogona. Glavni doprinos ove disertacije ogleda se u predlogu modela vibracionog transporta rasutog materijala, zasnovanog na elektromagnetnim aktuatorima, i u predlogu primene upravljačke strukture za kontrolu amplitude oscilovanja korita i protoka materijala, koristeći prediktivni kontroler. Budući da se postojeće upravljačke strukture vibracionog transporta uglavnom baziraju na primeni nekog oblika PID regulatora, ova disertacija značajno doprinosi razvoju upravljačkih struktura vibracionog transporta, što je omogućeno primenom brzih mikrokontrolera sa velikom računskom snagom. Za izrađeno eksperimentalno postrojenje izvršeno je modeliranje dinamičkog sistema objekta upravljanja. Nelinearni model sistema, u kontinualnom obliku, izrađen je primenom softverskog paketa MATLAB/Simulink. Razmatrana su dva algoritma upravljanja. Prediktivni algoritam upravljanja, zasnovan na primeni ''Model predictive control'' (MPC) kontrolera, i konvencionalni algoritam upravljanja, zasnovan na primeni PID kontrolera. Za obradu signala sa senzora pomeraja korita i za generisanje upravljačke promenljive koriste se dva zasebna mikrokontrolera STM32F407VGT6. Na osnovu dobijenih frekventnih karakteristika, jasno je da PI kontroler ima znatno širi propusni opseg. Ovakav rezultat je očekivan, s obzirom na prirodu MPC kontrolera. Dobijeni simulacioni i eksperimentalni rezultati potvrđuju da je usvojeni model vibracionog transportera sa elektromagnetnim aktuatorom prihvatljiv ukoliko se pobuđivanje aktuatora vrši strujnim impulsima čija je učestanost jednaka mehaničkoj rezonantnoj učestanosti transportera. Izvršena je eksperimentalna verifikacija usvojenog modela transportera i definisani su parametri pomoću kojih je moguće odrediti radnu tačku transportera sa maksimalnom energetskom efikasnošću. Ukoliko je ispunjen uslov da je brzina kretanja materijala kroz korito manja od kritične, promena mase koja opterećuje opruge je zanemarljiva i MPC kontroler predstavlja rešenje koje treba primeniti za sporopromenljive procese, dok PI kontroler treba primenjivati u sistemima koji zahtevaju znatno širi propusni opseg.

ABSTRACT: The application of electromagnetic vibration drive in combination with an energy converter allows for the vibration transport flexibility. In this way, a vibration-transport system, which acts as a controlled mechanical oscillator, is obtained. Regulated resonant electromagnetic transducers additionally provide high energy efficiency, which is reflected in the minimum value of the excitation current of the vibration actuator, the minimum power consumption and the improvement of the power factor of the entire electromagnetic drive. The main contribution of this dissertation is reflected in the proposal of the vibratory transport model of the bulk material, based on electromagnetic actuators, and in the proposal of application of the control structure for controlling the amplitude of the oscillation of the trough and the flow of material, using the predictive controller. Since the existing control structures of vibration transport are mainly based on the application of some form of PID controller, this dissertation significantly contributes to the development of control structures of vibration transport, which is enabled by the use of fast microcontrollers with large computational power. For the created experimental facility, a dynamic system of the management object was modeled. The nonlinear system model, in continuous form, was created using the MATLAB / Simulink software package. Two management algorithms were considered. Predictive control algorithm, based on the application of the MPC controller, and a conventional control algorithm, based on the application of the PID controller. Two separate microcontrollers STM32F407VGT6 are used to process the signals from the tilt sensor and to generate the control variables. Based on the obtained frequency characteristics, it is clear that the PI controller has a much wider bandwidth. This result is expected, given the nature of the MPC controller. The obtained simulation and experimental results confirm that the adopted model of a vibrating conveyor with an electromagnetic actuator is acceptable if the actuator's excitation is carried out by current impulses whose frequency is equal to the mechanical resonance frequency of the conveyor. Experimental verification of the adopted model of the conveyor is performed and defines the parameters by which it is possible to determine the operating point of the conveyor with the maximum energy efficiency. If the case is that the speed of material movement through the trough is less than critical, the change in the mass that bursts the springs is negligible and the MPC controller is a solution that should be applied to slow processes, while the PI controller should be applied in systems that require a much wider bandwidth.