Then we can tune the PPF parameters δ, δ¯, ϕi0 and thedesign parameters η1 , η2 and matrix P to guarantee thesuspension travel constraints (5). It should be noted that theparameters η1 and η2 are used for analysis only; they are notused in the control implementation. Thus, they can be set verysmall such that β1 is small to fulfill (35)–(37).