Class of suboptimal feedback policies for linear and nonlinear systems

A class of suboptimal feedback control policies which are easily implemented on line and which give a value for performance index close to the truly optimal is suggested. Necessary basic conditions are derived for a general nonlinear case and specifically applied to linear quadratic problems. Numerical computations are made for linear and nonlinear examples and the results are tabulated and discussed. It is seen that, particularly in the case of nonlinear systems, an integral state feedback introduced in the paper non only synthesises the control in a completely feedback configuration, but also improves system optimisation to a point where it is remarkably close to the truly optimal open loop.