# Research on LPV-H∞ control strategy of magnetorheological semi-active suspension with air spring

## TL;DR

This paper proposes an LPV-H∞ control strategy for magnetorheological semi-active suspensions to improve vehicle ride comfort and safety.

## Contribution

A novel LPV-H∞ control method is introduced to address parameter variations and disturbances in semi-active suspensions.

## Key findings

- LPV-H∞ control outperforms H∞ and passive control in terms of ride comfort metrics.
- The controller improved sprung mass acceleration by 11.60% compared to H∞ control.
- Vehicle performance on various road surfaces was significantly enhanced using LPV-H∞.

## Abstract

In order to improve the ride comfort and safety of the vehicle, a linear parameter varying H∞ control of magnetorheological semi-active air suspension was proposed to solve a series of problems caused by parameter changes and external disturbances. Based on the improved hyperbolic tangent model, the forward magnetorheological damper model was established, and the inverse magnetorheological damper model was established by using CNN. The accuracy of the mechanical model of the magnetorheological damper was verified by comparing the tensile test and simulation data. A linear parameter varying H∞ controller (LPV-H∞) based on quarter semi-active air suspension model was designed to solve the problem of time-varying system caused by the traditional H∞ optimal control which cannot observe and estimate the parameter changes in real time. After solving the controller through the LMI toolbox, simulations were carried out using speed bump road surface and random road surface, and real vehicle tests were carried out using continuous trapezoidal speed bumps road surface, bad road surface and Belgian road surface. The results show that the root mean square values of three performance indexes of MR semi-active suspension under LPV-H∞ control strategy are better than those of H∞ control and passive control. Compared with H∞ control, LPV-H∞ control increased by 11.60%, 14.26% and 23.12% in Sprung mass acceleration, Suspension working space and Dynamic tire Deformation, respectively. Compared with passive control, it is improved by 22.50%, 33.64% and 17.12%, respectively. LPV-H∞ control has a significant improvement in vehicle ride comfort.