Comparison between robust and multi-model controllers

Advances in microelectronics and software allow the implementation of some control laws in embedded systems. In this work, the STM32 microcontroller is used to implement a robust fixed low-order controller for linear systems. The parametric uncertainty model is employed to describe the system behavior and the controller objective is to ensure, in the presence of model uncertainties and disturbances at the plant output, some specified time response performances. The controller design is expressed as a min-max non-convex optimization problem while taking into consideration uncertainties and the desired closed-loop specifications. Consequently, the use of a local optimization method to resolve such kind of problem may lead to a local solution and then, the obtained control law is not optimal. Therefore, with the purpose of obtaining an optimal solution which will be able to satisfy the desired specifications, the application of a global optimization method is recommended. The optimization method exploited in this work is the generalized geometric programming. In order to evaluate the performances of the proposed method, the implementation of a fixed low-order controller by applying the multi-model approach is also considered.