Many practical problems in structural dynamics are modeled with a high number of degrees of freedom in order to properly describe the structure. A formulation to design robust controllers is theH∞technique where the controller has the same order of the mathematical model and this becomes unpractical and infeasible for most practical problems where the number of degrees of freedom is not small. One way to overcome this difficulty is to employ a model reduction technique, and design a reduced order controller based on this reduced model. In this case, it is required that the reduced controller ensures a good performance also for the nominal model (reduced) and for the real model (non-reduced) of the structure. Since the reduced controller is designed based on a truncated dynamic model, the non-modeled vibration modes can be excited causing the spillover phenomena, which is a severe undesirable effect. This work investigates the behavior of a reduced order controller obtained based on a reduced model through the Guyan reduction. TheH∞robust control and Linear Matrix Inequalities (LMI) formulations are employed to the problem of controlling a flexible structure subjected to an external disturbance. Some simulations are performed using a cantilever beam modeled by the finite element method. The results show that the Guyan reduced order model can be used to design a controller to the non-reduced model with success.
One of the main challenges for OEMs to reduce tailpipe emissions is to meet emissions regulation at minimum costs, keeping the vehicle at affordable price to the final customer. Starting in January 2022, all vehicles sold in Brazil will need to comply with PROCONVE L7 (PL7) emissions regulation. PL7 imposes more stringent emissions limits and new procedures to be followed such as the NMOG (Non-Methane Organic Gases) determination. This paper details the NMOG calculation with ozone formation potential corrections. The PL7 NMOG + NOx emissions limit is one of the biggest challenges when running tests with EHR fuel (reference hydrous ethanol) mainly due to aldehydes and unburned ethanol generation prior to engine warmup. The majority of NMOG is generated during the cold phase of ABNT NBR 6601 emissions cycle. This paper aims to detail potential actions to reduce NMOG and meet the PL7 emissions limit when running a light passenger vehicle with low displacement PFI (Port Fuel Injection), normally aspirated, three cylinders engine and fueled with EHR fuel. The emissions tests were run at Ford Tatuí Development Center.
Com objetivo de redução de custos e aumento de eficiência, as montadoras de veículos estão buscando alternativas para minimizar a demanda por protótipos veiculares durante a fase de desenvolvimento de projetos. Este estudo tem o intuito de demonstrar uma solução de Hardware in the Loop (HiL) que integra o Módulo Eletrônico de Controle do Motor (ECM) e o Painel de Instrumentos (IPC) em ambiente de bancada.
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