This thesis addresses the issues of design and mathematical model identification of an advanced hydraulic system referred to as Electro Hydraulic Actuator (EHA).

In the design part, insights into system design methodology are presented and used for the EHA prototype manufacturing. To get better knowledge of the system behavior, extensive open loop tests were performed. Test results are presented in the time and frequency domain, and it was concluded that system behavior is nonlinear.

In the modeling part, a nonlinear mathematical model of the EHA is derived. Some of the unknown model parameters had to be identified experimentally by optimization. The last step in the system mathematical modeling was open and closed loop model validation using the experimental data. Proposed nonlinear mathematical model gives good correspondence with experimental data and can be used for system studying or controller design.

Performed test show that the EHA system has high positioning accuracy (0.01mm), fairly high bandwidth (23 Hz with 20kg inertial load) and is easy to control. It shows significant benefits when compared to conventional hydraulic systems in the areas of control, efficiency and physical dimensions.