Abstarct: In this thesis a novel approach to control active suspension system by using the concept of impedance in mechanical systems that will be able to control the dynamic behavior of the system against road roughness is proposed. A quarter car is simulated as a model with an active suspension with a nonlinear electro-hydraulic actuator. The desired dynamic behavior of the system is modeled the suspension system as a second order system. The controller is designed in such a way that the suspension system can track the second order system. The output of the position control is a desired force produced with the electro-hydraulic actuator. The force should control to reach the goal so the control system has two loops. The internal loop controls the force and the outer loop is a position control loop. In this thesis fuzzy sliding mode impedance is used to control position of an active suspension system of a car and back stepping control used to control the force. The simulation results show the effectiveness of the method