Force control based on parameter estimation applied to fatigue testing machines
DIEGO PEREIRA-DIAS1; ALESSANDRO JACOUD PEIXOTO2; ALAN MACHADO DE ARAUJO1; RAMON ROMANKEVICIUS COSTA2; OSCAR ROSA MATTOS3
1 LNDC/COPPE/UFRJ; 2 PEE/COPPE/UFRJ; 3 LNDC/COPPE/EP/UFRJ
doi:10.20906/CPS/COB-2015-2333
Resumo
This paper addresses the force control of hydraulic fatigue testing machine (HTM) applied to material characterisation under corrosive and pressurised environment. It is verified via numerical simulations that the specimen stiffness variation due to the crack propagation should be compensated via force feedback. Since the specimen stiffness varies slowly, the system has two main time scales allowing us to use a normalised least squares identification algorithm to estimate the specimen stiffness which is subsequently used in the control design. The aim is to keep the force error within the standard limits while the specimen stiffness varies along the fatigue test. Simulation and experimental results are presented to demonstrate the effectiveness and feasibility of the proposed solution in real world conditions.
Palavras-chave: hydraulic fatigue testing machine ; Force control; Parameter estimation