Online System Identification of DC Motor Using LabVIEW-myRIO

Abstract

An accurate model is required for the design of a controller. In many cases some or all of the parameters are unknown to the designer. These parameters has to be identified using system identification technique. The important step in system identification is to collect the input and output data of the system by exciting the plant using some input signal such as Pseudo Random Binary Sequence (PRBS) signal, but it requires a large hardware support. Getting motivated from the above facts, this paper investigates the system identification of DC Motor in an user friendly LabVIEW-myRIO environment. The PRBS signal is generated in LabVIEW and applied to a 12V DC Motor with encoder through myRIO. The pulse from the encoder is converted in to rpm using LabVIEW Virtual Instrumentation (VI) program. The input-output data is collected in LabVIEW for every 50 ms. LabVIEW interact with MATLAB and estimate the unknown parameters using the Recursive Least Square (RLS) Algorithm. The obtained model with estimated parameters is validated by comparing its response with actual motor. The results are presented and discussed.