Abstract: A servo-motor control system having a load that is supported by a gear ring. The gear ring and the associated load are rotated by a driving wheel that is connected to the shaft of a servo motor. At least one transmitter rotatably contacts the gear ring at a point substantially 90.degree. from the point of contact of the driving wheel. As the gear ring rotates, the transmitter generates a control signal that corresponds to the angle of rotation of the gear ring and includes a backlash signal component corresponding to either the magnitude or speed of the backlash and/or resilience of the servo system. A measuring means rotatably contacts the shaft of the servo motor and generates a servo operating signal corresponding to the operational angle of rotation of the servo motor. The control signal and the servo operating signal are combined by an adder to generate a difference output signal having a component corresponding to the negative backlash signal component.

Abstract: The guidance system for a flying vehicle having at least one guidance channel for converting an error signal to a command signal for a control surface servo of the vehicle includes means for damping oscillations at the natural frequency of the vehicle. A damping means includes a notch filter in the guidance channel which serves to damp oscillations at the notch frequency. The notch frequency is controlled and conformed to the natural frequency of the vehicle, as the natural frequency of the vehicle varies with vehicle speed, by providing the notch filter with a signal related to vehicle speed. The notch filter is arranged to vary the notch frequency in accordance with the signal provided thereto.