A design method of universal model reference adaptive controller

A design method of universal model reference adaptive controllers for processes with uncertain relative degrees r, r+1 or r+2 (with known p∈N), and with unknown signs of high-frequency gains, is given. This is an extension of Morse´s (1985) universal adaptive controllers where it was assumed that the relative degrees are uncertain but known to be 1 or 2. It is shown that single adaptive control schemes can deal with unknown signs of high-frequency gains, and enlarged uncertainties of relative degrees compared with the previous works, and that the resulting model reference adaptive control systems are asymptotically stable