Abstract

In a control system having a manipulatable unit, such as an aircraft stick, which is biased toward a neutral position to provide control "feel", an input which at each instant signifies the position of displacement of the stick from its neutral position is processed to provide an output signifying the magnitude of the biasing force to be applied to the stick. In a range of positions spaced to one side of its neutral position (or in such a range at each side of neutral) the output provides for a steep biasing force gradient as the stick is moved through a predetermined distance in either direction from a turning point to which the stick had been brought by movement in the opposite direction. For all other movements of the stick within that range the biasing force has a low gradient. The higher gradient of bias for small trimming movements provides better feel for trimming without requiring stick bias to be unduly stiff during coarser stick displacements.