A performance comparison of nonlinear and linear control for a DC series motor

Résumé 0

The aim of this article is to compare the performance of linear and non-linear control in the case of a series wound DC motor. The research was focused on determining when the differences in the performance between these controllers are significant. The comparison was made on the MS150 feedback module and it included the phases of parameter estimation for the linear and the non-linear models, the statistical validation of these models and the design and implementation of the controllers. In order to make the comparison there were defined two performance criteria respectively based on the tracking error and on the control effort. These criteria were applied by considering three scenarios defined according to the range in which the velocity set point is varied. In the first scenario, the reference velocity remained constant and equal to the value of the operation point around which the linear model was obtained (60%). In the second and third scenarios the reference velocity was respectively increased from 40 % to 60 % and from 20 % to 100 %. From the experimental tests it was observed for the scenarios two and three that the tracking error and the control effort for the linear controller are superior to the non-linear ones. While for the first scenario, the linear controller presents a lower tracking error with an approximately equal control effort. From this work it was concluded that for reference velocities that are close to the operation point, the linear controller presents a significant advantage over non-linear controller.