Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Optimization of the LQR and SDRE control scheme for a non-linear semi-active MR damper on a quarter vehicle model
Submission Author:
Leonardo da Costa Rodrigues Ferreira , DF
Co-Authors:
Leonardo da Costa Rodrigues Ferreira, Marcus Vinicius Girão de Morais
Presenter: Leonardo da Costa Rodrigues Ferreira
doi://10.26678/ABCM.COBEM2023.COB2023-1202
Abstract
This work aims to compare the behavior of a semi-active suspension on a quarter vehicle model using the Linear-Quadratic Regulator (LQR) control scheme and one of its non-linear variations (State Dependent Riccati Equation - SDRE) per report to a passive suspension system. The semi-active suspension mathematical model is based upon equations of physically motivated models present in the literature, incorporating nonlinear behaviors such as force hysteresis and asymmetry. Due to this complex relationship between force and speed, the LQR technique is considered sub-optimal regarding control, leading to the deployment of better suited alternatives such as the SDRE technique to gauge the degree of inadequacy. To measure performance to form the basis for the comparisons, the movement of the vehicle is characterized using the H2 metric of the upper body and the H8 metric of the lower body, also known as the RMS gain and roadhold of the vehicle. A Gaussian white noise function is used for the road profile. The systems are evaluated using numerical integration methods. An optimization on the free parameters of the suspension control is performed by means of the NSGA-II Genetic Algorithm. The Pareto optimums of the metrics for the evaluated systems for each control scheme is found, with the system showing robustness with regards to the controller parameters. The SDRE control scheme showed better performance in both evaluated metrics, having significantly better H2 results.
Keywords
Semi-active suspension, non linear control, LQR controller, SDRE Control, Mr damper, Multi-Objective Optimization, genetic algorithm
