Application of the MRAC with simplified discrete parameter adaptation algorithm for control of the DC electromotor drive

Abstract

The application of the simplified model reference adaptive control algorithm with parameter adaptation, to the DC motor drive has been considered. DC motor drive, with a basic control loops and changeable moment of inertia belongs to the class of the higher order systems with changeable parameters. In a way to preserve the desired system behaviour, even in the case of system parameter change, the simplified MRAC algorithm with parameter adaptation was developed and applied for control of the DC motor drive. The algorithm is based on the classical model reference adaptive control approach with parameter adaptation, including few simplifications. The simplifications are as follows: the reference model and the state vector were reduced to the third order, only output variable was used in the algorithm and the total number of the algorithm coefficients was reduced to seven. The satisfactory behaviour of the adaptive control algorithm was preserved by using differences of the output variable instead of its derivatives. Furthermore, an adaptive control algorithm was normalized for the usage in the whole range of reference signal changing. Adaptive control coefficients were obtained by off line optimization, for the extreme amount of the changeable system parameter. Therefore, the same coefficients could be used in whole range of the system parameter variation. The simplified MRAC algorithm with parameter adaptation was implemented in the dSPACE DS1102 micro controller platform based on microprocessor TMS320C37. This controller is used for control of the DC motor drive with a changeable moment of inertia. Finally, it was evident from the experimental results that the application of the MRAC with the simplified discrete parameter adaptation algorithm significantly decreases the influence of the plant parameter variations and the influence of disturbance to the system behaviour.