Abstract : During the continuous casting of steel, several disturbances occur and affect all the parts of the caster, including the mould where the molten steel has to be stable for good quality of the final product. Especially at high casting velocities, it is difficult to achieve, using the conventional control schemes, both stability and performance robustness because of different classes of disturbances and parameters uncertainties in the process. Therefore, improved process control techniques are needed to cope with such obstacles. This thesis focuses on developing methods for designing controllers to force the level to respond in a desired manner to a setpoint change and to counter the effects of disturbances. An online monitoring of some of the most disruptive phenomena is also developed because more information is needed to improve casting inspection. In addition, particular attention is paid to reject some disturbances with the help of an estimator module. Since the process is prone to important variability, other needed developments include robust control design methods that incorporate other casting parameters such as mould section, tundish weight and argon flow rate. The water model is used to validate the theoretical developments and to investigate several important issues related to mould level control. The combination of these techniques is used as a sophisticated control tool for the continuous casting machine as well as for other iron and steel processes.