This paper is concerned with the design of robust controllers for active suspensions using μ methods, which take the structure of the model uncertainty into consideration. The complex μ method is conservative in the case of the real parametric uncertainty, while in the mixed μ method, both the real parametric and the complex uncertainties are handled together. Two half-car model structures are constructed, a rigid half-car model, and a high-order flexible one, which is more realistic and closer to the real situation. In the example, the result of the mixed μ method will be compared with the complex μ method and the traditional methods.