To effectively implement the nCOS function method, it is essential to accurately derive the nCOS function in relation to the relevant design parameters. Although the method is originally formulated for single-input single-output (SISO) nonlinear systems, its applicability can be extended to multi-input multi-output (MIMO) systems, as well as to nonlinear systems characterized by multiple optimization variables or non-polynomial nonlinearities, such as exponential functions. The critical step lies in transforming the system of interest into an equivalent set of SISO systems. This study focuses on vehicle suspension systems exhibiting inherent nonlinear behavior, which can be reformulated as single-input, multiple-output (SIMO) systems. Under this framework, the nCOS function method can be employed to establish a direct and analytically tractable relationship between controller gains and the objective function.