Elimination of the hysteresis effect of PAM actuator: modelling and experimental studies

Fluidic Muscle koji je proizvela Festo Company najviše je korišteni i istraživani tip aktuatora pneumatskih umjetnih mišića (PAM - pneumatic artificial muscle) koji se može okarakterizirati kao snažan i dinamičan (čak 6000 N, 50 m/s2), bez vibracija i otporan na prljavštinu i prašinu. Stoga se ti aktuatori uvelike koriste u industriji uz električne motore ili hidraulične aktuatore. Jedan od najviše spominjanih nedostataka PAMova je postojanje histereze. U ovom se radu opisuju dva eksperimenta povezana s pojavom histereze kod PAMova. Cilj je predstaviti točan model statičke sile za krivulju histereze u krivulji sila-kontrakcija (pomak u odnosu na silu) i regulator stanja klizanja za točno pozicioniranje neovisno od histereze na temelju LabVIEW. Uz primjenu algoritma aproksimacije za silu koju je ostvario Fluidic Muscle postignut je korelacijski koeficijent R od gotovo 1 i 0,01 mm točnosti u pozicioniranju.Fluidic Muscle produced by Festo Company is the most used and investigated type of pneumatic artificial muscle (PAM) actuators which can be characterized such as powerful, dynamic (even 6000 N, 50 m/s2), judder-free and resistant to dirt and dust, therefore these actuators are widely used in industrial environment besides electric motors or hydraulic actuators. One of the most mentioned drawbacks of PAMs is the existence of hysteresis. In this paper two experiments related to hysteresis phenomena of PAMs are described. The goal is to present a precise static force model for the hysteresis loop in the force-contraction (force-relative displacement) curve and a LabVIEW based sliding mode controller for hysteresis independent accurate positioning. Using the approximation algorithm for the force produced by the Fluidic Muscle the correlation coefficient R of nearly 1 and 0,01 mm accuracy in positioning is reached