1.
\((I)\)在平面直角坐标系\({xOy}\)中,直线\(l\)的参数方程为\(\begin{cases} x{=}t\cos\alpha \\ y{=}t\sin\alpha \end{cases}(t\)为参数\()\),以原点\(O\)为极点,\(x\)轴的正半轴为极轴建立极坐标系,曲线\(C_{1}\),\(C_{2}\)的极坐标方程分别为\(\rho =4\cos \theta \),\(\rho =2\sin \theta \).
\((1)\)将直线\(l\)的参数方程化为极坐标方程,将\(C_{2}\)的极坐标方程化为参数方程;
\((2)\)当\(\alpha{=}\dfrac{\pi}{6}\)时,直线\(l\)与\(C_{1}\)交于\(O\),\(A\)两点,与\(C_{2}\)交于\(O\),\(B\)两点,求\(\left| {AB} \right|\).
\((II)\)已知函数\(f\left( x \right){=}\left| 2x{-}a \right|{-}\left| x{+}1 \right|\).
\((1)\)当\(a{=}2\)时,求\(f\left( x \right){ < -}1\)的解集;
\((2)\)当\(x{∈}\left\lbrack 1{,}3 \right\rbrack\)时,\(f\left( x \right){\leqslant }2\)恒成立,求实数\(a\)的取值范围.