Abstract: An electro-hydraulic servo control system which has N dynamic state variables and includes a servo actuator adapted to variably position a load mass. An actuator control system includes sensors coupled to the actuator for providing indications of X measured state variables, such as actuator position and/or velocity, and a digital observer responsive to the X measured actuator variables for estimating the remaining N-X variables at the actuator such as velocity and/or acceleration. Signals indicative of measured and estimated state variables are fed to a comparator together with a state command signal, for obtaining a difference or error signal to provide a control input to the actuator. The observer electronics include digital computation means suitably programmed to estimate N state variables as solutions to N linear equations for N unknowns.

Abstract: An electro-hydraulic servo control system which includes a servo actuator adapted to variably position a load mass, and an actuator control system which includes a sensor coupled to the actuator for providing an indication of measured actuator position and a digital observer responsive to measured actuator position for estimating velocity and acceleration at the actuator. Signals indicative of measured actuator position, estimated velocity and estimated acceleration are fed to a comparator, together with a position command signal, for obtaining a difference or error signal to provide a control input to the actuator. The observer electronics includes digital computation means suitably programmed to estimate position, velocity and acceleration as solutions to three linear equations with three unknowns. Equation constants, which are functions of actuator and driven mass physical characteristics, are entered through operator-adjustable resistors.