We present an approach to network control analysis that applies to some important time-dependent dynamical states for both autonomous and non-autonomous dynamical systems. In particular, the theory applies to periodic solutions of autonomous and periodically forced differential equations. The key results are summation theorems that substantially generalise previous results. These results can be interpreted as mathematical laws stating the need for a balance between fragility and robustness in such systems. We also present the theory behind what has been called global sensitivity analysis where sensitivities are defined in terms of principal components and principal control coefficients.