“…In order to development of the analytic design method of
DOB,
8,13 proposed pseudo loop factorization and shaping (PLFS) method, in which the
norm condition on complementary sensitivity function for the robust stability is transformed into the
norm condition on Q‐filter itself and then standard
solution framework is applied to analytically derivate the optimized high order Q‐filter. In Reference
31, this method was employed to design high order DOB for attitude stabilization control of a two axes gimbal system. However, the model uncertainties in these applications were parameter variations of the plant but not uncertain time delay.…”