Abstract: Gradually increasing and decreasing the friction torque feedforward term in time, prior to and immediately following intended motion, respectively, reduces the effects of variations in Coulomb friction load in an open loop step motor system.

Abstract: Gradually increasing and decreasing the friction torque feedforward term in time, prior to and immediately following intended motion, respectively, reduces the effects of variations in Coulomb friction load in an open loop step motor system.

Abstract: A stepping motor which includes a rotor and a stator having a plurality of poleshoes extending inwardly in closely spaced relation to the rotor, each of the poleshoes being disposed in one of a plurality of groups of poleshoes. Each poleshoe in each of the groups is uniformly angularly spaced from each other adjacent poleshoe in the same group, and each group is angularly spaced from each adjacent group by an angle which is different from the angle between adjacent poleshoes in the same group.

Abstract: In the disclosed electro-mechanical system of a stepping motor and its control circuit, positive electrical damping is provided for avoiding loss of synchronism and loss of torque over the range of intermediate and high stepping frequencies by imposing a self-adjusting limit on the motor current over a period of time longer than any prominent period of parametric oscillation of the system and supplying current to the motor with a d-c supply having high impedance.

Abstract: A power control unit causes a high supply voltage to be intermittently chopped to provide energy pulses in a core transformer and the energy in the core is discharged into a capacitor with the capacitor constituting the power source for a stepping motor and with the extent of the energy pulse accepted by the capacitor being determined by the condition of the capacitor which in turn is set by the instantaneous operating state of the motor.

Abstract: The tendency of a unipolar energized stepping motor, having a circuit for enabling the self-decay of winding currents, to oscillate or flutter under some mid-velocity conditions is minimized by reducing the deviation of the motor's rotor from the synchronized position dictated by the energization of its winding by inversely altering the time about a nominal time when a change of the motor's energization is to occur after receipt of an input pulse in accordance with the extent of the decay current in the winding being deenergized.

Abstract: A chopping power supply controls power to the bifilar winding phases of a stepping motor with the power being applied to one winding until a selectable value of current flows and is then removed for a fixed duration to have induced current in the other winding be directed back to the power source while still producing usable magnetic flux and in which each phase has its own chopper circuit with both being operated at super-audible rates at least during standstill operation.

Abstract: A method and system for producing relative movement of an element along two perpendicular axes to closely approximate a desired path with the movement being sub-divided into a plurality of successive lengths with a determination being made of the number of steps for each axis that is needed to constitute each length. The number of steps in adjacent lengths on each axis is made to vary only within a constant amount so that the minimum and maximum lengths of each next length is determinable from its preceding length. The determination for each length involves calculating in one operation the deviation from the desired path for a minimum length and then calculating the addition of individual steps thereto within limits of deviation and velocity to arrive at the most acceptable length. This reduces the number of calculations as compared to prior known systems which calculate each individual step.

Abstract: A numerical control system and method for providing actual relative movement along a path commanded by the distance along three perpendicular axes by digital movement in each axis. The actual movement is sub-divided into a plurality of successive final lengths each of which may include a movement on each axis. The extent of each final length is determined by initially determining the extent of a length that is most acceptable as to deviation and velocity on the two axes having the largest and middle commanded distance and then setting the extent of the final length by determining the most acceptable extent as to deviation on the axis having the smallest distance. Each final length is made to have an extent on each axis which bears a numerical relationship with the movement on the same axis for the immediately prior length.

Abstract: A method and apparatus for producing relative arcuate movement which may be greater than one quadrant for each input command by subdividing the movement into a plurality of sequential linear lengths of varying extent and proper direction. The extent of each length is defined by the number of steps of movement to be produced simultaneously over the same time interval on each of the pair of perpendicular axes. The extent of each length is determined to be that which both maintains the actual movement within a maximum deviation from the commanded path and is within the change of velocity limitation of the system thereby inherently providing acceleration and deceleration as well as not excessively exceeding any feed rate command.The method and system further selects the extent of the length from a group of possible extents by investigating which extent is most acceptable having regard to relative emphasis of path deviation and velocity error. The relative emphasis may be set by input commands.

Abstract: A circuit for causing command pulses to control the energization of a two winding phase bifilar stepping motor to produce a step or half step by either one or both phases being energized for each command pulse and in which the circuit self-generates command pulses which have a minimum selectable base rate.

Abstract: One coil of a bifilar winding of a stepping motor is energized until the current therein reaches a set value and then energization is terminated which creates an induced current that supports the magnetic flux produced by the energizing current and in which the duration of the induced current is increased by being directed through both coils of the winding thereby decreasing the motor's power requirements.

Abstract: A system for accepting a number and causing the same number of steps to be produced by a stepping motor with the motor essentially linearly accelerating to a settable maximum velocity and then linearly decelerating in small velocity changes to the end of the movement with the deceleration duration being inversely related to the maximum velocity.

Abstract: The ability of a stepping motor to assume the same static rotational position for each step when a step position results from simultaneous energization of two windings is enhanced by having the same quantity of current flow through both windings by always connecting in series the windings that are energized with the source of unidirectional power.

Abstract: A circuit for accepting a train of command pulses produced as a number of evenly spaced pulses for each consecutive equal time interval and which may have abrupt small changes in rates between adjacent time intervals and providing a motor pulse for each command pulse to a digital pulse to step motor circuit with the motor pulses having less abrupt rate changes and lagging its corresponding command pulse generally by about the extent of a time interval and in which the deviation of the position of the motor's rotor from its energized dictated position also alters the rate of the motor pulses in order to decrease the tendency of the motor to flutter, oscillate and/or lose synchronism especially when the motor is operating at a light or no load within a moderate velocity range.

Abstract: A system for directing sequential commands to a plurality of device control circuits, each of which is capable of being individually addressed and controlled to perform one of a plurality of modes of energization by the input commands. The control circuits are used to control energization of devices, such as peripheral devices of numerical control machines and may utilize feedback status signals from the devices, in some modes, to regulate the receiving of further input commands. The commands may be each acted upon sequentially or some may be grouped to be acted upon simultaneously.

Abstract: The tendency of a stepping motor to oscillate or flutter under some mid-velocity conditions is minimized by reducing the deviation of the motor's rotor from its normal synchronous position by altering the time about a nominal time when a change of energization of the motor's windings is to occur after receipt of an input pulse in accordance with the duration of the decay current that existed at the prior change of energization.

Abstract: Linear velocity changes between steps are obtained by a digital circuit in a stepping motor system that receives commands of the number of steps to be produced in successive time intervals by providing a string of pulses during each interval and selecting certain of said pulses to provide motor steps with the selection being initially determined by the number of commanded steps in the interval and further being determined by whether the number of commanded steps for the interval has the same number of steps, a greater number or a lesser number than in the immediately preceding interval.

Abstract: A system for accepting commands of the number of steps in a movement and for producing motion commands in a motion system that divides the movement into the number of steps in successive time intervals with the motion commands consisting of altering the number of steps between adjacent time intervals that are required to produce the movement.

Abstract: A circuit for supplying an error signal when the instantaneous difference between the number of command pulses and the number of steps produced by a stepping motor exceeds a value from which the motor cannot recover to overcome the difference.