Abstract: In a control method wherein a control signal is generated in response to the deviation of a process variable signal from a setpoint signal and the time integral over this deviation, the windup of the respective controller is prevented by automatically modifying this deviation by a signal representative of the difference between the control signal and the process control signal such as to reduce the deviation of the process variable signal from the setpoint signal by an amount representative of the difference mentioned.

Abstract: A microprocessor-based controller for a stepper motor driven machine tool compensation system is disclosed. The step pulses for the motor are stored in the controller firmware as a table of numbers, each number representing the time elapsing from one motor step command to the next, thus enabling precise generation of the desired motor velocity versus time characteristic. The controller additionally interprets compensation system command inputs, drives a system display unit, and activates appropriate output status signals to the compensation system and machine tool apparatus. The controller is capable of detecting impending commercial power failure and protecting, via battery back-up power, its volatile random access memory.

Abstract: In a control apparatus for a machine tool, a resolver interface circuit is utilized to determine whether or not the axis motors have driven the machine tool to the selected position. The resolver interface circuit synthesizes sine and cosine wave forms which are applied to a resolver which is mechanically coupled to the corresponding axis motor. The resolver interface circuit also synthesizes a signal which is phase related to the resolver excitation wave forms by the selected rotational displacement of the resolver and axis motor shafts required to achieve the selected position for the machine tool. The phase related signal and a positional feedback signal from the resolver are compared to generate an error signal to the driver for the axis motor. The selected position can be each incremental step where the axis motor is a stepping motor.

Abstract: An encoder interface circuit is responsive to command direction signals and pulsed command incremental rotation signals and to actual direction signals and pulsed actual incremental rotation signals to generate an error signal to a motor driver for controlling the movement of a servo motor. A position encoder is mechanically coupled to the servo motor for generating the actual direction and incremental rotation signals. The interface circuit generates a reference pulse train and an error pulse train, both at a relatively high frequency. The error pulse train is phase modulated by adding or subtracting the pulsed actual and command incremental signals according to the state of the corresponding direction signals. The reference and phase modulated error pulse trains are then compared to generate the error signal to the motor driver.

Abstract: A stepping motor turns 45.degree. for each step in response to a digital control signal different than the signals for other step adjacent thereto. An angle sensor produces a digital position indicating signal for sectors centered about the step positions and of the same magnitude as the angle between motor steps. The position indicating signal for a sector corresponds to the digital signal of the motor step that falls within that sector. An evaluation circuit comprising a microprocessor produces an error signal when, after a predetermined elapsed time after receipt of a control signal, a corresponding position indicating signal is not received. The evaluation circuit also checks for correspondence of signal within a minimum time after receipt of a control signal, and failing to find such correspondence assumes that the motor has not performed the directed step.

Abstract: A theoretically optimum motor drive time period or drive pulse width is computed as a function of the number of steps from the present motor shaft step to the desired command step. A compensation time period is computed as a function of a previous motor drive time period and combined with the computed drive time period to produce a present drive time period for energization of the motor (12) for movement of the motor shaft (14) from the present step to the next step.

Abstract: The phases of a multi-phase stepping motor (16) are individually energized to rotate the motor shaft (14) to a desired step position. A sensor (12), (27) driven by the shaft (14) is constructed to generate a plurality of position signals (L1), (L2), (L3) equal in number to the motor phases. The position signals (L1), (L2), (L3) are symmetrical and are displaced in phase from each other by the angle (15.degree.) between adjacent shaft steps. These signals (L1), (L2), (L3) are decoded to energize the motor phases in such a manner as to rotate the shaft (14) to a next step during rotation of the shaft (14). A hold decoder (26) decodes the position signals (L1), (12), (13) to energize the motor phases in such a manner as to hold the shaft (14) at the desired step when rotation of the shaft (14) is stopped. If the shaft (14) is manually rotated to another shaft position, the hold decoder (26) will energize the motor phases in a different manner so as to hold the shaft (14) at the new step.

Abstract: Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes an electronic switch connected in series with the coil for selectively connecting the coil to a source of direct current, and a device adapted for providing an electronic digital signal having a frequency proportional to motor speed.

Abstract: A programmable automatic assembly system is provided which may be employed to assemble small parts. Each assembly station includes cooperating manipulator arms which are programmable to assemble parts on a centrally located work table. Improved facilities are provided for teaching the manipulator arms at each station, these facilities including a computer which assists the teaching operator in setting up the programs required for assembly of small parts to close tolerances. Each manipulator arm includes closed loop teach facilities for maintaining the arm at a previously located position during the teaching mode of operation. The computer is employed as a teach assist facility in performing a number of tasks during the teaching operation which are extremely difficult for the operator to perform manually. All of the assembly stations may be controlled during playback from a common disc storage facility so that the control circuitry and memory storage facilities at each manipulator are minimized.

Abstract: Apparatus and a related method for detecting failures of control elements, such as skewed-axis reaction wheels with closed-loop speed control, used in satellite attitude control systems, and for compensating for such failures and thereby maintaining continuity of operation. The apparatus includes a wheel loop model for simulating operation of each of the reaction wheels and speed control loops in the satellite, and for deriving an estimated wheel speed from a command speed for each wheel. By comparing the estimated speed of each wheel with the corresponding actual or observed speed, the apparatus determines whether a failure was occurred in the wheel, or in its control loop.

Abstract: A programmable automatic assembly system is provided which may be employed to assemble small parts. Each assembly station includes cooperating manipulator arms which are programmable to assemble parts on a centrally located work table. Improved facilities are provided for teaching the manipulator arms at each station, these facilities including a computer which assists the teaching operator in setting up the programs required for assembly of small parts to close tolerances. Each manipulator arm includes closed loop teach facilities for maintaining the arm at a previously located position during the teaching mode of operation. The computer is employed as a teach assist facility in performing a number of tasks during the teaching operation which are extremely difficult for the operator to perform manually. All of the assembly stations may be controlled during playback from a common disc storage facility so that the control circuitry and memory storage facilities at each manipulator are minimized.

Abstract: A numerically controlled transfer machine comprises a rotary index table having thereon a plurality of jig tables for holding workpieces, and a plurality of working units are disposed in spaced relation around the index table so that rotary indexing of the index table successively positions the jig tables opposite different ones of the working units. Each working unit includes a positioning feed mechanism for controlling the feeding and return movements of the working unit to enable a working operation to be carried out on the workpieces. Each working unit has a position detector comprised of a microswitch mounted on a slide member slidably mounted on the working unit.

Abstract: In a control device of an AC motor wherein a torque equivalent to that of a DC motor is created by controlling the instantaneous values of its stator current, or in a vector control device, signals from a position detector such as a resolver coupled to the AC motor are utilized to form stator current instruction signals and to provide rotation position feed-back signals and rotation speed feed-back signals for the AC motor, thereby to perform precise servo-control.

Abstract: An apparatus for controlling the length of movement of a controlled member along a path of repeated operating positions. The apparatus comprises a function generator with an axis digital integrator for each axis of movement of the controlled member and a resultant length of movement digital integrator. All digital integrators have the same input iterate rate. By initially setting the integrand of the resultant length of movement integrator to the square root of the sum of the squares of the initial integrand values of the axis digital integrators of the function generator, the output of the resultant length of movement digital integrator is proportional to the resultant of the distances commanded along the axes by the axis integrators of the function generator. A counter is set to the incremental distance between repeated operating positions and is counted down by the output of the resultant length of movement digital integrator.

Abstract: A stepping motor with toothed stator poles and two sets of oppositely magnetized rotor teeth has its stator poles energized by a driver which responds to input pulses to successively deenergize alternate poles and keep them deenergized and then successively reenergize the alternate poles in the opposite direction. Thereafter the driver successively deenergizes the poles intermediate the alternate poles and keeps them deenergized until all intermediate poles are deenergized and then successively reenergizes the intermediate poles in the other direction until all the intermediate poles are reenergized. This drives the rotor in fractional steps. For larger fractional steps, larger numbers of poles are deenergized in response to each pulse. For even larger fractions the deenergization process is eliminated.

Abstract: In order to provide high accuracy shaft angle to linear DC voltage conversion using low accuracy devices, a linear synchro is excited by a 2.5 KHZ square wave which is power buffered, the square wave also used to synchronously demodulate the output of the wound component by sampling and a demodulated voltage then filtered and scaled to the required levels using commonly available operational amplifiers.

Abstract: This invention concerns a method for the synchronization of a gear machining instrument that works according to the hobbing method. It has different drives for the tool and the work-piece. In the process, a series of pulses are produced, dependent upon the rotational speed of each drive. The occurrence of the pulses are compared digitally resulting in an analog control signal for the adjustment of the work-piece drive.

Abstract: In a variable reluctance electric drive system motor the fractions of a cycle during which the winding inductance of a phase increases with movement in either direction are such that the motor is self starting in either direction. The timing of the power converter in relation to the cycle of inductance is such that the current increases from its minimum value to substantially its maximum value while the winding inductance is substantially at its minimum value and thereafter substantially decreases before the power converter disconnects the winding from the supply. This can be achieved by making the switch-on and commutation of current occur at predetermined positions so related to the variation of inductance that the peak current ip at maximum power and maximum speed, is greater than I, where I=E/(R+dL/dt), E is the supply voltage, R the winding resistance and dL/dt is the maximum rate of increase of inductance before the commutation point.

Abstract: A digitally controlled acceleration and deceleration system in which the goal velocity applied to the object in the acceleration mode and the deceleration mode changes linearly, instead of the flat goal velocity, thus, the acceleration and/or deceleration applied to the object to be controlled in the feedback loop becomes flat, and the acceleration time and/or deceleration time is reduced. The outputs of the variable frequency pulse generator and the fixed frequency pulse generator are combined together to provide said goal velocity, and the number of the sum of two pulse generators is utilized as a command position for the movement of the object.

Abstract: A control installation for a dental apparatus which has at least one part capable of being moved to a selected position of a plurality of positions characterized by the control installation including a drive motor for moving the part to the selected position, a clock pulse generator coupled to the drive motor creating a pulse received by a pulse counter, a read-only memory producing a nominal or reference value indication, a comparator comparing the nominal value indication with the indication of the counted pulses to produce an error signal which is applied to a switching amplifier and then to the drive motor so that the operation of the drive motor depends on the presence of the error signal with the direction of rotation of the drive motor depending upon the operational polarity of the error signal.