Authors' reply [to comments on "A composite energy function-based learning control approach for nonlinear systems with time-varying parametric uncertainties"]

For original paper see ibid., vol.47, p.1940-5 (2002); for comment see ibid., vol.48, no.9, p.1671-2 (2003). In that paper, a composite energy function learning control approach was proposed to asymptotically eliminate the mismatch between the desired and actual periodic trajectory of a system. The comment highlighted alleged technical errors, especially in light of the fdadt that the boundedness of the learning estimate has historically been a problematic issue. The authors defend their work, pointing out that learning control needs different designs and requires different conditions when addressing different tasks, and acknowledging some error.