Saturation prevention for MIMO LPV controllers: An error governer approach

In many applications, it is essential to limit control signals. This paper presents methods that process accessible system signals (e.g., plant and compensator states, reference commands) to limit control signals. In contrast to "classical techniques" which limit variables by unnecessarily reducing control system bandwidth, the proposed methods limit variables in a nonconservative manner, reducing bandwidth only when necessary. A fundamental contribution of this work is that the methods presented are applicable to linear parameter varying (LPV) and quasi-LPV plants and controllers. The methods presented rely on appropriately "scaling back" key signals. The methods are conservative in that they are applicable to "slowly varying" LPV systems. Although the methods require access to all internal closed loop system state variables, one could use an appropriately designed LPV state estimator, if necessary. The Error Governer (EG) methods are applied to an LPV missile autopilot example.