Abstract: Trajectory correlation and error detection apparatus is provided for use with a programmed manipulator to detect movement during an operational work cycle outside a predetermined volumetric envelope. The trajectory correlation and error detection apparatus stores positional data representations of the manipulator during an observed acceptable operational work cycle and compares those stored positional data representations with the actual positional representations during subsequent work cycles to thereby detect an error mode. The detected error during an operational work cycle may be caused by a memory readout malfunction, drive train system malfunction, manipulator positional representation apparatus malfunction, control circuitry malfunction, etc.

Abstract: This invention relates to the protection of power transistors in an H configuration power amplifier which drives a D.C. motor. When the amplifier is switched off, it may be possible for the base terminals of the transistors to be turned "on" which results in the transistors conducting. If two series transistors conduct, the resulting short circuit may damage or destroy the transistors. This invention provides an easy and economical apparatus for protecting the transistors in the power amplifier by grounding the base input terminals of the power transistors during all times when the transistors are switched "off.

Abstract: There is disclosed a gap eliminator used for reducing working cycle time in machine tools. With over-all voltage variations in power sources in a factory taken into consideration, an output .function.(t.sub.0) under no or light load condition of an electric motor and an output k.function.(t) obtained by attenuating an output .function.(t) under loaded condition by an attenuator circuit are compared with each other to provide a primary signal, by which the feed rate is controlled. In this operation, particularly when an output obtained through a detecting circuit is an electric power, a circuit for eliminating periodic noise is disposed immediately after the electric power detector in order to eliminate adverse effects on power waves of periodic noise due to a belt. Further, abnormal overload condition is detected to provide a secondary signal, by which the machine is brought to a stop. Other merits and details of the arrangement will be made clear.

Abstract: A string of short pulses is impressed across the input circuit of a multipoint recorder and a pulse magnitude detecting circuit. If the input circuit is open, the magnitude of the pulses appearing at the pulse magnitude detecting circuit is higher than would be the case if the input circuit were completed by a normal input device. The pulse magnitude detecting circuit is operable to apply to the measuring circuit of the multipoint recorder a positive potential whenever the pulse detecting circuit detects pulses of a magnitude indicating that the input circuit is open. As a result, the multipoint recorder is driven upscale to its limit where the particular point which is open-circuited is identified by a printed indicia.

Abstract: Monitoring apparatus for redundant control systems includes means for preventing the monitoring apparatus from failing to a "good" state. Each of the channels in the redundant system generates a command signal which is compared to a signal provided by adding the command signal generated by another of the channels to a tracer signal. The amplitude of the addition signal is such so that the comparator toggles between its "good" and "fail" states to obviate failure of the monitoring apparatus to its "good" state.

Abstract: A system for controlling the operation of a numerically controlled machine tool used for cutting threads on workpieces, in which means are provided so that the quality of the products may not be adversely affected even when the thread cutting operation is interrupted for some reasons incidental to the thread cutting.

Abstract: A positioning device for a critical aircraft surface, such as a stabilizing elevator in a helicopter, includes a pair of reversible electric jack-screw type actuators acting in series, each being controlled in a closed-loop fashion by separate electronic hardware, the position of each as well as the rate of change thereof being compared with the other, against limits which, according to the invention, are relatively broader at low speeds and are tightened at higher speeds. If either of the positions or the rate of change of positions of the two actuators fail to track within the variable threshold disparity, an alarm condition is manifested and the actuators are disconnected from automatic control and rendered operable by manual control.

Abstract: A system for rapidly disengaging, with minimum nuisance disengagements, a nventional autopilot system upon detecting hardover failure, which is defined as any autopilot failure which results in rapid and sustained displacement of an aircraft aerodynamic control surface. The aircraft pitch rate is measured and compared with established limits. If these limits are exceeded, the system causes automatic disengagement. Disengagement is inhibited for gust disturbances by deriving a nose up or down signal from the pitch rate signal which is then compared with a signal indicating the direction of elevator hinge moment; if the two directions are opposing, disengagement is inhibited. Disengagement is also inhibited in the event of pilot action. Also, the autopilot pitch axis command line is monitored and a disengagement overriding any inhibits is generated when the signal on that line exceeds certain limits for the altitude hold mode and for the attitude hold mode of the autopilot.

Abstract: A limiter circuit is installed in a servomechanism that establishes a signal at the output terminal of a filter contained therein, in the absence of an input signal within the lock range of the servomechanism, in a manner that maintains the charge on the filter consistent with the established output signal, thus providing favorable initial conditions for rapid reacquisition and smooth reacquisition transients.

Abstract: In a prime mover control system, control over the prime mover is dependent, in part, upon the validity of a reference signal to the control system. Circuitry is provided between a reference signal generator and the control system whereby under normal conditions the reference signal to the control system is the same as the output of the reference signal generator. However, if the reference signal generator output becomes invalid, then a stored reference signal may be substituted for the reference signal generator output by switching from a first signal channel to an alternate second signal channel, each channel selectably interconnecting the reference signal generator and the control system.

Abstract: Three-axis attitude control of a substantially zero momentum satellite is achieved by a control system which includes three mutually orthogonal reaction wheels and a fourth backup reaction wheel. The backup wheel is mounted on an axis which is skewed with respect to the axes of the three mutually perpendicular wheels. Spacecraft attitude is normally maintained by torques developed by the mutually orthogonal wheels. If one and only one of the orthogonal wheels should fail to correct the attitude error on its associated axis, the backup wheel is caused to rotate and develop a torque to maintain spacecraft attitude.

Abstract: A digital type controller for a punch press or the like which includes a shaft angle encoder for generating control pulses corresponding to specific main shaft angles of the machine, a plurality of sensors for generating signals in response to the operating condition of the machine and process, a plurality of circuits for enabling the reception of said signals at selectable shaft angles of the machine, a plurality of circuits for enabling the reception of said signals in a selectable prescribed order, a plurality of circuits for storing said signals, a plurality of circuits for sampling the stored signals at selectable shaft angles of the machine, a plurality of circuits which detect the presence or absence of the sampled signals, an output circuit for deenergizing the machine Run control circuit when an absence of a sampled signal occurs, a plurality of circuits for energizing and deenergizing external electrical loads at selectable shaft angles of the machine, and a shaft encoder/decoder which provides cont

Abstract: A control system for hydrofoil craft is one in which control surfaces are moved automatically in response to signals derived from the motion of the craft to stabilize and control the craft. In such systems, a potentially dangerous condition can occur in case of a failure or malfunction in the roll control system. In order to prevent such conditions, two roll sensing devices are provided which normally generate identical signals to actuate the control surfaces to stabilize the rolling motion. In case a failure or malfunction, the signals provided by the two sensing devices become different and apparatus is provided to compare these signals and to respond to a difference in the signals to initiate landing of the craft rapidly and safely.

Abstract: The disclosure relates to a method and apparatus for checking and monitoring the movement of a tool carriage in response to a numerical controlled program. The path of movement of the tool carriage is recorded independently of the program control during the initial run of the carriage, in a manner capable of being subsequently sensed. The recorded path is thereafter sensed during the subsequent runs of the carriage and a signal is produced when the carriage deviates from the recorded path. The recording device includes a stationary supporting member having a surface upon which a drawing or etching may be made. The drawing or etching member is mounted to the movable carriage so as to become jointly movable therewith. The sensing member is mounted in conjunction with the drawing instrument and is interchangeable therewith during the sensing portion of the procedure.