Problems associated with reaction mass actuators used in conjunction with LQG control on the Mini-Mast

The work being done at NASA LaRC on developing control laws for the Mini-Mast experimental facility is reviewed with particular attention given to the problems associated with the stroke limit of the reaction mass actuators used in conjunction with the LQG control. An algorithm for converting the force commands of the LQG algorithm into position command for the reaction mass devices is described. It is shown that the position command can be used as an input to a local controller so that the relative position of the reaction mass would track the commanded relative position. The stabilization of the integration scheme makes it possible to avoid the position drift arising in the direct double integration method of converting force commands to position commands.