Abstract: A servo-system includes a high-gain direct-coupled direct current (dc) differential amplifier to which a dc input signal is fed. An adder adds the dc amplifier output to a comparison voltage, and the adder output is applied through a filter circuit to a second input of the differential dc amplifier. A servo-amplifier drives a servo-motor in accordance with the dc amplifier output. Means are provided for zero-balancing the dc amplifier output while varying the comparison voltage by the servo-motor.

Abstract: A servo system wherein a servo motor is continuously controlled in response to a pulse width modulated digital command signal is disclosed. A servo motor having a variable output is controlled in response to a variable amplitude error signal. A pulse code converter converts a pulse code modulated digital command signal to provide a pulse width modulated digital command signal for controlling the variable output of the servo motor. The digital command signal is provided at a predetermined frame rate in response to a frame pulse signal. A feedback transducer and network senses the variable output of the servo motor and provides a variable amplitude feedback signal that is indicative of the variable output. A synchronous pulse forming network converts the variable amplitude feedback signal to a proportional pulse width modulated digital feedback signal. The digital feedback signal is provided at the predetermined frame rate and in synchronization with the digital command signal.

Abstract: A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.

Abstract: In a control device which includes an integrating positioning drive comprising a motor and transmission with backlash and lag, the backlash being the hysteresis of the transmission of mechanical quantities which occurs when the direction of rotation changes and which is caused, for example, by gear tolerances in the transmission due to manufacturng constrains, in addition to a first feedback path which supplies a signal proportional to the position of a control member, there is also provided a second feedback path developing a signal dependent on the positioning rate and the magnitude of the lag in the motor and, the mechanical members of the positioning drive are designed in such a manner that the transmission lag which occurs is greater than the sum of the position changes of the control member during starting of the positioning member over the period from stand-still to reaching its nominal speed and the position change occuring during the lag after the positioning motor is deenergized, providing a control

Abstract: An inverse timer for a process line is disclosed in which the forward end of the material is detected at a known distance from an instrument which is to be activated. The inverse timer is initiated upon forward end detection, and in a small increment of time, .DELTA.T seconds later, the instrument is activated; .DELTA.T is equal to the time required for the material to move from the point of detection to the location of the instrument, i.e., the transport time minus the reaction time of the instrument. The inverse timer includes two potentiometers for independently adjusting the transport time and the reaction times. Since the velocity of the material may vary widely during production, the inverse timer enables rapid adjustments to be made to accommodate for these new conditions without the laborious empirical determination of optimum settings of interacting potentiometers.

Abstract: A nonlinear servo compensator for insertion in the position servo loop of a robot or automatic machine comprising a direct path with an operational amplifier and a second amplifier for summing the direct signal and its derivative; and a shunt path with an inversion circuit, an analog multiplier, a resistive divider, a follower amplifier and a differentiating circuit.

Abstract: In a plotting apparatus such as a spectrophotometer having a modifying system which introduces a phase lag between the occurrence of a change in a dependent variable quantity and plotting thereof against an independent variable quantity, in one embodiment, a cam is used to provide a quantity representing the dependent phase lag and the output of the cam is coupled to the driving system for the plotter so as to introduce therein a phase shift to compensate for the phase lag. In another, electrical embodiment the same object is accomplished by digitizing the phase lag and using the digital value to offset the wavenumber stepper motor and the chart stepper motor in the spectrophotometer with respect to each other.

Abstract: A device is disclosed for damping the critical frequencies of a rotor suspended by a radial electromagnetic bearing which has means associated therewith for detecting the radial position of the rotor, comprising a servo-circuit for connection between the detecting means and windings of the electromagnetic bearing and including a circuit for controlling the current supply to the windings in response to signals from the detecting means to keep the rotor in a predetermined radial position. The servo-circuit is provided with means for the selective amplification of the phase advance gain of said circuit in a frequency equal to the speed of rotation of the rotor for damping said critical frequencies.

Abstract: A system for providing a stable caging loop for two-degree-of-freedom dry tuned gyros used in a strap-down inertial navigation system. The system provides satisfactory noise rejection and good navigation accuracy using cross axis torquing only with extremely simple analog shaping circuits in place of the combination of cross axis and direct axis torquing with complex shaping circuitry that is normally required with these gyros in such an application. A 64 Hz bandwidth loop is provided with less than 1.degree. phase lag below 5 Hz, 10 db attenuation of rotor spin rate noise, and at least 35 db attenuation of all higher frequencies. Its performance is such that it can be used in a navigation system requiring accuracy on the order of one nautical mile per hour in a typical missile environment.

Abstract: A redundant channel control system includes one or more voters having a high-pass filter connected between a pair of voter inputs.

Abstract: An automatic control system wherein repetitive pulses, the frequency of which is responsive to a remote condition, such as prime mover RPM, are converted to a DC voltage level. The voltage level is compared to a reference by a difference amplifier to produce an error signal. Further signals are produced from the error signal, including an integral thereof, which signals are ultimately used to control the remote condition. The integrator is provided with an offset circuit to prevent saturation thereof during override of the normal control signal by an external limit signal as, for example, excessive engine temperature or smoke output.

Abstract: A self-adjusting regulation system comprising a regulator embodying an input adder for forming the difference of the feedback magnitude and the command magnitude as well as a regulation device for forming an adjustment magnitude from such difference. A linearity detector produces a control signal upon the occurrence of a non-linear behaviour of the regulation circuit. A supplementary adder is arranged between the input adder and the regulation device and has its first input connected with the output of the input adder and its output connected with the input of the regulation device, whereas its second input is connected with the output of a supplementary device composed of a number N of similar integration stages forming a series. Each stage contains an integrator and an auxiliary adder, the output of which is connected with an input of the integrator via a control switch which can be actuated by the control signal.

Abstract: A control system is specifically designed to improve the performance of an aircraft or other vehicle having undesirable dynamic characteristics. For this purpose there is employed a compensator, either hydromechanical or electrical (hydro-electrical) depending upon the basic control system, which is incorporated into that system and modifies command inputs to the directional controls of the vehicle. This compensator is designed and preset to impose predetermined dynamic characteristics on the command inputs so as to create a resulting input which eliminates or substantially diminishes the undesirable dynamic characteristics.

Abstract: In the measurement of a variable process parameter and control of the process in response thereto, the time derivative of a second order or higher lagged process measurement signal is utilized to provide predictive capability in generating a process variable signal, in generating a process control signal, and in controlling the process in response to the measured parameter. The system is particularly well adapted to control of a non-self-regulating process.

Abstract: A velocity-change control system and method are described for numerical control machines enabling the programming of higher speeds of operation for curved and straight-line paths while reducing positional errors and maintaining the acceleration and deceleration at a prescribed value. The system includes a hardwired digital logic unit for each axis interposed between the axis path generator and the axis drive. The input to each axis unit corresponds to the programmed path and velocity and is in the form of electrical pulses each representing a small fixed increment of motion for the particular axis. The output is in the form of pulses representing the same resolution of motion as the input pulses but providing an output trace which lags the input trace by a distance related to the path velocity.