Abstract: An electronic speed error signal processing circuit is provided which attenuates rapid fluctuations ocurring in the speed error signal used to control the fluid inlet valve of a fluid driven prime mover. Such fluctuations contribute greatly to valve wear by causing "valve flutter," the continual rapid opening and closing of the inlet valve as the speed control system of a prime mover instantaneously responds to any small speed error signal fluctuation. By attenuating these rapid fluctuations, valve flutter is reduced.

Abstract: An apparatus to produce accurately limited angular or pivotal movements of a shaft of a DC motor with a control circuit to supply appropriate signals to control the operation thereof. Position indicators are provided to detect the shaft position and a second indicator is located to detect a rearward pivot position. Means are provided to establish a direction signal to indicate direction of rotation of the shaft, and the direction signal means and the position indicators produce outputs which are connected to the control circuit. The DC motor has a motor drive which receives signals from the control circuit during movement of the motor between forward and rearward pivot positions. The control circuit produces, first, an acceleration current and then a deceleration and finally a correction current with the current dropping to "zero" when the desired angular position has been reached by the shaft.

Abstract: A servo control system for maintaining a direct current motor in operation at a constant speed is provided with two velocity feedback control loops. One feedback control loop is a rate damping loop which responds quickly to minor variations in motor speed to hold the motor at a predetermined command speed. The other loop is a steady state error loop through which a command speed is fed and which responds much more slowly to variations in command speed. The utilization of dual velocity control loops allows the servo system to adjust motor speed quickly in response to deviations in actual motor speed from commanded speed, yet is sensitive to low frequency variations in velocity feedback such as result from disturbances in motor loading.

Abstract: The stiffness of a second-order damped servo system with position and velocity feedback circuits is increased without affecting the command response, damping factor, or natural frequency of the system by adding an acceleration feedback circuit and maintaining a specified relationship between the effective gain of the acceleration feedback circuit and the effective gain of the servo driver.

Abstract: This invention relates to a driving signal control circuit, in which at least four detecting points (or detectors) are arranged for detecting the position of the working table, which is repeatedly reciprocated between the detecting points.

Abstract: A servo system incorporating an attenuator for reducing the error signal an amount proportional to the magnitude of the error signal so as to minimize overshoot without affecting the stability in the system.

Abstract: A signal compensator for a position servo loop system to attenuate the position error signal and provide stability at a larger band width by limiting the position actuator current in selected frequency ranges.

Abstract: A control system for a d.c. motor, in which a cyclical d.c. drive signal is applied to the motor power input terminals as the system approaches balance. In each cycle, during at least part of the time interval between drive signal application to the motor terminals, a very low impedance (virtually a short circuit) is applied to the motor terminals. These braking pulses provide progressive braking as the motor approaches its balance point, limiting overshoot and ensuring a return without hunting from an overshoot condition to the balance point. As the system nears its deadband range, each braking pulse exceeds in duration the electrical time constant of the motor and constitutes a substantial portion of its associated cycle.

Abstract: A method of controlling a motor in which an elastic element is coupled in a sub-critically damped manner to the load and the natural frequency of the system which comprises the elasticity of the element and the mass of the driven part is utilized to cause the speed of the load to increase and to decrease as quickly as possible.

Abstract: A filter is provided to substantially nullify the effect of process noise of less than a preset amplitude limit on the measurement of a process variable. The filter passes on to a controller or other device all signal changes greater than this amplitude. Within the amplitude limit the signal is damped by a first order lag with a filter time constant typically at least an order of magnitude greater than the average period of the noise to be filtered, but outside the amplitude limit, signal changes are passed immediately with no lag to a device such as a controller. The filter functions by generating a compensating signal essentially duplicating the process noise and then subtracting this compensating signal from the filter input signal, thus canceling this noise from the signal passed to the controller or other device. By subtracting only a limited value of this compensating signal from the filter input, changes of input greater than this limit are not compensated, and are thus immediately passed with no lag.

Abstract: This is concerned with an electric circuit for controlling or damping the shock loading on the structural components and parts of machinery which are moved by a conventional hydraulic cylinder. It is more specifically concerned with a control circuit to be used with a proportional control valve so that the mass moved by the cylinder will be gradually accelerated and decelerated to avoid abrupt starts and stops.