Abstract: A novel robust tracking control design method was proposed for hypersonic vehicles with timevarying uncertainties. Compared with traditional robust controller with fixed gains， the method presented had better capability to deal with large timevarying parameter perturbation and enhance the robustness of hypersonic vehicles. Sufficient conditions for controller design were given in the framework of robust optimization technique， and the controller gains was online adjusted based on the designed switchinglaws. The proposed robust tracking controller could not only guarantee the stability of hypersonic vehicles， but also track the command signals about height and speed quickly， even in the case of external disturbance existing. Some numerical simulations demonstrated the validity of this new robust control method.

Key words: hypersonic vehicle, timevarying uncertainty, controller with variable gains, tracking control, robust control