Estimation of dynamic model of a missile fin with freeplay by using system identification methods

In this study, an approach which is easy to apply, requiring less computational time and representing the real dynamis better (more accurate) has been developed to estimate the dynamic model of a missile fin with freeplay by using system identification methods. First, by using the time data obtained from the force controlled test method and displacement-controlled test method and the frequency data calculated from the time data, the mathematical models of the system were obtained by using auto regressive with exogenous inputs (ARX) and output error (OE) methods. Afterwards, whether the obtained models have embedded dynamics or not were checked by examining the correlation of each model within itself. Then, the mathematical model that is most appropriate to the test data obtained by force and displacement controlled test methods was selected as the model that defines the system. After that, the modal parameters of the system have been obtained by using the chosen model. As a result, it has been observed that the system identification model obtained from the ARX model using the time data of the displacement-controlled test is the most appropriate model representing the dynamics of the missile fin with freeplay.