A general scheme that combines piecewise-linear control, low-high-gain control and over-saturation to achieve high performance in the presence of input saturation

The effect of input saturation on control system performance depends on the range of control action required relative to the saturation bounds. Much of the prior work on this topic has centred on how to switch linear controllers so as to avoid saturation occurring. This, however, has meant that the full input authority has not been exploited in the control law. Recently, two alternative methods have been proposed for switching linear controllers so as to force the input into saturation. They achieve this goal by scaling the controls or by allowing over-saturation in the switching scheme. In the paper the two methods are shown to be special cases of a more general scheme. It is also shown that the combined scheme is capable of achieving superior performance