Master's Thesis from the year 2020 in the subject Engineering - Automotive Engineering, Jimma University College of Agriculture and Veterinary Medicine, language: English, abstract: To improve the road handling and passenger comfort of a vehicle, a suspension system is provided. An active suspension system is considered to be better than the passive suspension system. In this thesis, 2 degrees of freedom of a linear quarter car active suspension system is designed, which is subject to different disturbances on the road. Since the parametric uncertainty in the spring, the shock absorber, mass and the actuator has been considered, robust control is used. In this thesis, H∞ and μ− synthesis controllers are used to improve the driving comfort and the ability to drive the car on the road. For the analysis of the time domain, using a MATLAB script program and performed a test using four disturbance inputs of the road (bump, random, sinusoidal and harmonic) for the suspension deflection, the acceleration of the body and the body travel for the active suspension with the H∞ controller and active suspension with μ− synthesis controller and the comparative simulation and reference results demonstrate the effectiveness of the presented active suspension system with μ− synthesis controller. In addition, in this thesis, comparison have been made between the active suspension system with μ−synthesis controller and 5 different robust controller for suspension deflection, body acceleration and body travel tests using bump, random, sinusoidal pavements and harmonic road disturbances. Body accelerations comparison of the active suspension system with μ−synthesis controller with VW (Volkswagen) Passat B5 passenger car is done for a bump road input disturbance and the result shows that there is a 50% reduction in body acceleration for the active suspension system with μ− synthesis controller.