“…It should be pointed out that most of the existing results with either the logarithm ‐type BLF or the tangent ‐type BLF are mainly based on the backstepping design and focused only on systems in the strict‐feedback form, which is a special case of system with p i =1 for all i =1,…, n . Therefore, the schemes in other works are inapplicable to system on account of the inherent nonlinearities resulting from both p i 's and ϕ i ( t , x , u )'s. For example, consider the planar system , , y = x 1 with p 1 =5 and .…”