A structural equivalence between nonlinear and linear adaptive controllers

The mathematical structure of a linear adaptive controller is compared with the structure of several conventional types of nonlinear adaptive controllers. Through a term-by-term comparison of the equations representing each control law, using certain identity relations, it is shown that the structure of a linear adaptive control law is essentially equivalent to the structure of conventional nonlinear adaptive control laws. This result demonstrates that linear adaptive controllers are genuine adaptive controllers, and not just another form of robust controller