“…Bifurcation control refers to the task of designing a controller to modify the bifurcation properties of a given nonlinear system, thereby achieving some desirable dynamical behaviors. Typical bifurcation control objectives include delaying the onset of an inherent bifurcation [Tesi et al, 1996;, introducing a new bifurcation at a preferable parameter value [Abed, 1995;Chen et al, 1998b], changing the parameter value of an existing bifurcation point [Chen & Dong, 1998;Moiola & Chen, 1996], modifying the shape or type of a bifurcation chain , stabilizing a bifurcated solution or branch [Abed & Fu, 1986, 1987Abed et al, 1994;Kang, 1998aKang, , 1998bLaufenberg et al, 1997;Littleboy & Smith, 1998;Nayfeh et al, 1996;Senjyu & Uezato, 1995], monitoring the multiplicity [Calandrini et al, 1999;Moiola & Chen, 1998], amplitude [Berns et al, 1998a;Moiola et al, 1997a], and/or frequency of some limit cycles emerging from bifurcation [Cam & Kuntman, 1998;Chen & Moiola, 1994;Chen & Dong, 1998b], optimizing the system performance near a bifurcation point [Basso et al, 1998], or a combination of some of these objectives Chen 1998Chen , 1999aChen , 1999b. Bifurcation control with various of objectives have been implemented in experimental systems or tested by using numerical simulations in a great number of engineering, biological, and physicochemical systems; examples can be named in chemical engineering [Alhumaizi & Elnashaie, 1997;Moiola et al, 1991], mechanical engineering [Liaw & Abed, 1996;Wang et al, 1994b;Cheng, 1990;Gu et al, 1997, Hackl et al, 1993…”