Design:

For the superposition of the action has to be verified:

on simultaneous action of F₁ and F₃/F₄

$\backslash frac\{F\_\{1,d\}\}\; \{R\_\{1,d\}\}\backslash le1$

and

$\backslash frac\{H\_\{d\}\}\; \{R\_\{H,d\}\}\backslash le1$

and

$\backslash left(\backslash frac\{F\_\{1,d\}\}\; \{R\_\{1,d\}\}\backslash right)+\backslash left(\backslash frac\{H\_\{d\}\}\; \{R\_\{H,d\}\}\backslash right)\backslash le1,4$

on simultaneous action of F₂ and F₃/F₄

$\backslash left(\backslash frac\{F\_\{1,d\}\}\; \{R\_\{1,d\}\}\backslash right)+\backslash left(\backslash frac\{H\_\{d\}\}\; \{R\_\{H,d\}\}\backslash right)\backslash le1$