where W 1 ( s ) = K a K ϕ K m ϕ ( 1 + τ a s ) ( 1 + τ m s ) + K a K m ( K ϕ ϕ ) 2 {\displaystyle W_{1}(s)={\frac {K_{a}K_{\phi }K_{m}\phi }{(1+\tau _{a}s)(1+\tau _{m}s)+K_{a}K_{m}(K_{\phi }\phi )^{2}}}} (10)