Hierarchical fuzzy controllers for explicit MPC control laws: adaptive cruise control example

Abstract

This paper presents a methodology to approximate explicit Model Predictive Control (MPC) laws by hierarchical fuzzy systems, particularly piecewise-affine hierarchical (PWAH) systems. These hierarchical controllers provide high operation speed with low cost in computational and memory resources because they are formed only by single-input and single-output (SISO) fuzzy modules connected in cascade. The methodology employs the CAD tools of Xfuzzy environment to describe, adjust, verify, and implement the controllers in a Field Programmable Gate Array (FPGA). The methodology is illustrated with the design and FPGA implementation of a hierarchical controller for a car adaptive cruise control (ACC) system. The resulting controller is better in terms of speed and FPGA resource consumption than other solutions reported in the literature.