Um Sistema de Controle Utilizando Algoritmo NAP Aplicado a uma Unidade Experimental no Controle de Vazão

Abstract

—A L´ogica Paraconsistente (LP) vem sendo pesquisada para que seus algoritmos possam ser aplicados com ˆexito em diversos campos da ´area industrial. Entre estes campos, destacam-se: a rob´otica, a eletrˆonica, e controle de processos (que pode associar l´ogica com t´ecnicas convencionais de controle). Esta pesquisa teve como objetivo principal a implementac¸˜ao de um algoritmo denominado de N´o de An´alise Paraconsistente (NAP), em um Controlador Program´avel (CP), algoritmo este baseado nos princ´ıpios e fundamentos da L´ogica Paraconsistente Anotada com anotac¸˜ao de dois valores (LPA2v), que ´e um ramo da LP. Nesta implementac¸˜ao do algoritmo NAP, houve a aplicac¸˜ao direta deste em uma malha de controle real, cuja vari´avel controlada foi a vaz˜ao. Detalhando, o NAP foi implantado em uma unidade experimental, composta por: dois reservat´orios, transmissor de vaz˜ao, bomba, inversor de frequˆencia e software supervis´orio, onde foi poss´ıvel realizar o controle da vaz˜ao em tubulac¸˜ao entre os reservat´orios. Para tornar poss´ıvel o uso do NAP, foi criado um bloco funcional na programac¸˜ao do CP, denominado NAP PARACON, o qual recebeu o sinal de setpoint (SP) – correspondente ao valor de vaz˜ao desejado pelo operador na tubulac¸˜ao –, e o sinal da vari´avel de processo (VP), que representou a vaz˜ao medida na tubulac¸˜ao pelo transmissor de vaz˜ao. Assim, o bloco funcional 61131, n˜ao- Paraconsistente, Controle de vaz˜ao. Abstract —Paraconsistent logic (PL) algorithm applications have been researched for a successful implementation in various industries, including robotics, electronics, and process control (which might associate logic with conventional control tech-niques). The purpose of this study was to implement a paracon- sistent analyzer node (PAN) in a programmable controller (PC), based on annotated paraconsistent logic principles and funda- mentals with annotation of two values (PAL2v) — a branch of PL. The PAN algorithm was directly implemented in a real control loop on the flow rate variable. It was implemented in an experimental unit with two reservoirs, a flowmeter, a pump, a frequency inverter, and supervisor software to control the flow rate through a pipeline connecting both reservoirs. The PAN was made possible through a NAP PARACON functioning block programmed into the PC, which received a setpoint signal (equaling the desired flow rate through the pipeline) and the process variable (PV) signal representing the flow rate from the flowmeter. Thus, the NAP PARACON functioning block acted as a paraconsistent control system, receiving both input signals (SP and PV) and emitting an output signal to the frequency inverter, which controlled the pump speed, and consequently, the intended flow rate. The results obtained demonstrated reliable PAN algorithm behavior, similar to that of the proportional–integral–derivative algorithm, providing a new alternative for closed-loop processes, based on the paraconsistent control action. This technique, using PAL2v, expands the initiative concurrently with item 3 of the IEC 61131 standard, which specifies the application of nonclassical logics in PCs.