title: Comment on "Control of hyperchaos".
abstract: In this Comment we show that the adaptive adjustment mechanism proposed by Shouliang, Shaoqing, and Hengqiang [Phys. Rev. E 64, 056212 (2001)] does not ensure that the feedback system will converge to the desired orbit as the real system is, in general, not known.
authors.affiliation: Departamento de Engenharia Elétrica, Universidade de São Paulo, 13566-590 São Carlos SP, Brazil.
authors.forename: Vilma A
authors.initials: VA
authors.lastname: Oliveira
authors.forename: José R
authors.initials: JR
authors.lastname: Rosolen