Abstract: Velocity, at which a work point of a robot passes through respective reference points, has previously been given magnitude and directions dependent on a relative positional relation between a plurality of continuous reference points. The work point passes through the respective reference points. Between adjacent reference points, interpolation arithmetic is performed along the above condition, whereby the work point defines a smooth locus in accordance with the result of the arithmetic.

Abstract: A method of interpolatively controlling the movement of an arm portion of a robot along a line between predetermined first and second spatial positions which comprises teaching and playback steps. The teaching steps include inputting and storing in a teaching data storing memory the values of coordinates defining the first and second spatial positions, inputting and storing in the memory the predetermined velocity of the arm at the first spatial position, and determining from the coordinates and velocity stored in the memory the distance to be traversed by the arm between the first and second positions and the time required for this traversal. The playback steps include dividing the traverse time by a predetermined time unit to obtain a plurality of time-separated interpolation points and calculating sequentially incremental coordinate values for each of distance-separated points, corresponding to the time-separated points, from the stored coordinate values.

Abstract: This invention relates to a machining apparatus for repeating the position and the attitude of a desired point on a work, memorizing as a plurality of data in a memory device, and automatically operating a jig from the stored point to the stored point in accordance with calculated result of a calculator for calculating to interpolate between these points while a machining head remains stationary. The device comprises a detector for teaching the position and the attitude of the machining head with respect to the work independently from the machining head in case of forming teaching data. A calculator is provided for calculating the spatial position and attitude entirely in the same manner as the detector with respect to the work by the stored data under playback condition so that the machining head takes with respect to the work.

Abstract: An end effector move is executed by transforming the end effector position and orientation into joint coordinates at a large number of points on the end effector trajectory. On-line joint trajectories are determined in real time by looking ahead a few points on the end effector trajectory and generating points along the different joint trajectories. The current point and the look-ahead points are referred to as a block. An initial estimate of the slope at the block end points is made and then improved by overlapping the next block with the current block. The coefficients of the polynomials converting the points in the joint trajectories are interpolated to provide position commands to a servo control associated with the robot joint to control robot joint motion.

Abstract: A numerical controller of the type in which acceleration or deceleration processing is performed by an acceleration/deceleration circuit (7) prior to an interpolation by an automatic mode distributor (1); a smooth acceleration or deceleration is carried out when a distribution pulse from a manual mode distributor (2) is superimposed by an adder 3 on a distribution pulse from the automatic mode distributor (1). To achieve this, the command pulse to be superimposed is also subjected to independent acceleration or deceleration processing by an acceleration/deceleration circuit (10).

Abstract: A curvilinear interpolation system and method for use in a numerical control apparatus such as a machine tool or a robot having two or more drive axes and movable while effecting linear interpolation on a given curve with a plurality of line segments. For each line segment a curvature K.sub.p of the curve is calculated at a current curve interpolating point P.sub.p, and a curvature K.sub.n calculated at a point P.sub.n on the curve spaced a given search length l.sub.S from the point P.sub.p along the curve. Then, a curvature K.sub.s is set equal to K.sub.p when K.sub.p .gtoreq.K.sub.n and set equal to K.sub.n when K.sub.p <K.sub.n. The curvature K.sub.s is compared with a limit curvature K.sub.L established for determining whether a curve portion is a straight line or an arc for establishing the curve portion as an arc having the curvature K.sub.s when K.sub.s .gtoreq.K.sub.

Abstract: A numerical control system suited for application to a machine tool having an axis of rotation, such as a robot which employs a cylindrical coordinate system. For example, when the arm (3) of an industrial robot is rotated to transport a wrist (2), which is attached to the end of the arm (3), from a starting point (P.sub.1) to an end point (P.sub.2), the straight line (L.sub.n) interconnecting the starting point (P.sub.1) and the end point (P.sub.2) is divided into a plurality of intervals {Q.sub.i, Q.sub.(i+1), . . . }, positional data for each axis at each of the division points is generated, and linear interpolation for each of the intervals is performed by using the positional data for each axis to move the wrist (2) approximately along the straight line.

Abstract: A method of controlling a robot is disclosed in which the displacement of each of a plurality of kinematic pairs of a robot is detected by a detector, the present spatial position of a hand or tool of the robot is calculated on the basis of the detected displacement of each kinematic pair, a set position to be occupied by the hand or tool and a deviation of the present position of the hand or tool from the set position are calculated, the speed of the hand or tool is determined in accordance with the deviation, a desired displacement value or speed of each of the kinematic pairs is calculated from the speed of the hand, and actuators are controlled on the basis of the calculated displacement values or speeds of the kinematic pairs to drive the kinematic pairs.

Abstract: A machine present position region discrimination method divides a stroke, over which a movable portion of a machine travels along a single controlled axis, into n equal parts to partition the stroke into regions, each region having a length I. A region number is assigned to each region sequentially from one end of the stroke to the other. A present position region number A is incremented or decremented in dependence upon the travelling direction when an accumulated travelling distance B of the movable portion of the machine exceeds the region interval length I (during movement in the positive direction), or is less than zero (during movement in the negative direction). The resulting present position region number A, which is indicative of the present position region of the movable portion of the machine, is supplied by an NC unit in which the present position region number A is calculated to the controlled machine.

Abstract: A technique of determining the distribution of pulses along two perpendicular X-Y axes of a numerically controlled machine can be used for linear, circular, and parabolic interpolations and may be extended to computer graphics. At the initial point on the curve and at each succeeding point, a decision is made to increment the X axis, the Y axis, or both axes. This decision is based on a deviation index which is an index of closeness to the desired curve. Hardware is minimized and involves only additions, compares, shifts, and increments/decrements.

Abstract: A method is disclosed for machining multiple entry threads on a workpiece. The preferred steps of the method are preferably carried out in conjunction with a computer-based numerical control system. The method includes the steps of: determining the angular position of the workpiece as it is being rotated by a machine tool spindle; determining the desired separation of thread entry points; specifying the angular position of the workpiece at the start of tool motion for cutting a first thread on the workpiece, the angular position being stored as a reference angle; and for each subsequent thread, starting motion of the cutting tool from the first thread starting point whenever the angular position of the workpiece is displaced from the reference angle by an amount equal to the desired entry point separation from the first entry point, the motion being maintained along the identical path used to cut the first thread.

Abstract: A control system and method for controlling a hand of an industrial robot are disclosed wherein the hand is driven at a predetermined speed along a polygonal path defined by a plurality of straight lines which interconnect a plurality of point coordinates taught to the robot. The straight lines are continuously interconnected by a parabola at predetermined locations in the vicinity of the centers of the straight lines, wherein the hand is continuously moved along the parabola from a straight line to the next straight line, and wherein the parabola is generated by dividing a span between two predetermined positions through arithmetic linear interpolation technique in a manner in which points located between the predetermined positions are defined on a straight line interconnecting the two predetermined positions.

Abstract: A numerical control method for executing numerical control processing using a numerical control unit (102), based on a machining program having plural items of command data recorded on an NC tape (101). Under the numerical control method, numerical control processing is executed based on a succeeding item of command data which has been preread or which has been read after completion of numerical control processing based on an item of preceding command data. An upper limit feed speed (V.sub.L, V.sub.C), based on a workpiece shape commanded by the machining program and on an allowable machining error, is previously determined and stored in registers (RG1, RG2). The magnitude of the upper limit feed speed (V.sub.L, V.sub.C) and the magnitude of an actual feed speed (Vi) is compared, and the actual feed speed is clamped to the upper limit feed speed V.sub.L, V.sub.C, even when Vi exceeds V.sub.L or V.sub.C.

Abstract: A process for acquiring data representative of at least one contour of an object by means of a feeler constrained to move in a plane, consisting of storing a succession of coordinates representative of a succession of contact points between the feeler and the object, these coordinates defining successive poles, and further associating to said successive poles a succession of arcs of circle whose radii are close to the radii of curvature of portions of the contour.

Abstract: A path control method and apparatus which are well-suited especially for application to articulated machine tools and industrial robots having path-controlled parts, using commands calculated from teach point information and orders calculated from the commands by operations performed without coordinate transformations so that a large number of path points can be evaluated without considerably lengthening an operating period of time.

Abstract: A method of and apparatus for controlling the path of an industrial robot, in which a slight change in the shape of the work or the position of the work relatively to the robot, if any, can be detected by a position detection arrangement capable of detecting the work position, and a previously given data concerning the path of the robot is corrected in accordance with the result of the detection by the position detection arrangement, so that the range of work conducted by robot, such as welding, sealing and so forth, is broadened advantageously.

Abstract: Disclosed is a numerical control method for positionally controlling a movable element of a machine tool in such a manner that numerically controlled machining is performed along a projected path obtained by projecting a programmed path, lying on a predetermined plane, onto a plane of projection inclined at a predetermined angle with respect to the first-mentioned plane. The method includes the steps of entering data specifying a programmed path on the predetermined plane, subjecting the entered data to a projective transformation in accordance with entered projection angle data to generate projective transformation data specifying the projected path, and performing an interpolation on the basis of the projective transformation data to produce an output signal indicative of the results of the interpolation, and positionally controlling the movable element on the basis of the projective transformation output signal.

Abstract: A numerical control method for moving a tool along a commanded curve on a curved surface, which includes entering the curved surface defined by data representing a mathematical expression or by a group of numerical data, entering numerical control data specifying a projected curve obtained by projecting the commanded curve onto a predetermined plane, successively finding positional coordinates on the commanded curve through use of the curved surface data and numerical control data specifying the projected curve, and controlling the position of the tool on the basis of the positional coordinates.

Abstract: A numerical control method for controlling a numerical control device and prereading the numerical control data in a succeeding block during the execution of numerical control in accordance with the current block. A plurality of line segments, each specified by a block of numerical control data, approximate a curve. When the length of a line segment is less than a prescribed length (defined by required machining precision), control of movement of a member such as a tool based on the data specifying said line segment is skipped. This eliminates intermittent tool movement, improves machining precision, and prevents damage to the machine tool.

Abstract: A numerically controlled machine tool for producing tangential entry into a compensated contour and for the tangential leaving from a compensated contour. The numerically controlled machine tool also produces the interior or exterior rounding of intersections between two contours.

Abstract: A method and apparatus are disclosed for providing very precise incremental motion of a numerically controlled machine tool, or other similarly controlled object, along a circularly arced path. For a mutually perpendicular X and Y coordinate system, X and Y indices are determined based on certain prescribed input information related to the parameters of the circular path and the relative rate of motion between the machine tool and the workpiece, and on immediate, continuously recomputed, coordinates of the tool or object. The indices are each scaled by a modulus related to the radius of the arc to generate incremental distances .DELTA.X and .DELTA.Y according to which the next move is to be made. The process is reiterated until the desired circular path is complete. In both method and apparatus, only integer values of .DELTA.X and .DELTA.Y are used for implementing each increment of motion. Non-integer values are carried forward to the next iteration of the process to prevent error accumulation.

Abstract: A calibration system for a programmable manipulator having a base and a plurality of segments movable with respect to each other includes a fixture for attachment to the base of the manipulator and a hand-held application module for directing the operation of the programmable manipulator, including a calibration mode operation for initiating calibration of the programmable manipulator. The fixture has an end point to which the end effector of the programmable manipulator attaches. The end point is exactly positioned and oriented with respect to the base thereby establishing a known position and orientation of the end effector. The link lengths (distances between centers of rotation) of the programmable manipulator segments are entered and a computation is made of the displacement between each pair of the plurality of segments and compared with a measured displacement. The difference is an offset which is stored for future correction.

Abstract: A method and apparatus for circular interpolation on the basis of a given arc center O, arc starting point P.sub.s and arc end point P.sub.e. In a case where the given arc end point P.sub.e does not lie on an arc of center O passing through the given arc starting point P.sub.s, a new center O.sub.N of an arc passing through the points P.sub.s, P.sub.e is computed, and circular interpolation is performed on the basis of the computed center O.sub.N, the given starting point P.sub.s and the given end point P.sub.e.

Abstract: A manipulator and control are provided for moving a function element carried by the manipulator in accordance with programmed input signals defining positions and path velocities therebetween of a tool centerpoint associated with the function element. The path velocity is made susceptible of variation in accordance with unprogrammed variations of a parameter manually or automatically produced. Motion of the tool centerpoint is effected by interpolation of intermediate point along a predetermined path between any two preprogrammed positions. Each intermediate point is displaced from its predecessor by an increment computed in accordance with a fixed increment interval period and an instantaneously variable increment velocity. Incremental velocity values are computed selectively in accordance with a simple function relating the variable parameter and velocity and in accordance with the preprogrammed definition of motion.

Abstract: The process of linearly interpolating between data taken from adjacent storage locations in a memory non-integrally addressed has the initial subtraction and final addition steps eliminated from it, and the partial products to be summed in the intervening multiplication process are modified to compensate for the elimination of these steps. This modification is done with a relatively fast select-one-of-four process, reducing the time for linear interpolation to that required for a simple multiplication--or, in the case of a single-bit multiplier, to the time for selection of the modified multiplicand to be used as linear interpolation result.

Abstract: Milling machine apparatus and method for controlling the relative movement between a working surface and a cutting edge in which said relative movement approximates a mathematically definable path and occurs in a series of line segments each intersecting said path at first and second points with the second point of each line segment being the first point of the next successive line segment. The system comprises first means for determining a maximum distance d' between each successive line segment and said path measured along a line extending from a predetermined reference and passing between said first and second points, where d'=d+.DELTA.d, a predetermined range of value. Also provided are second means responsive to the determination of d' for each successive line segment to then establish the first point of intersection of the next successive line segment, and control means responsive to the determined points of intersection to generate prime moving control signals.

Abstract: A teaching-playback type robot is disclosed having a manipulator with a plurality of movable members connected to each other, a detector detecting the relative positions of the members, a switch for designating position signals from the detector upon a teaching operation, a memory for storing position signals from the detector, an interpolating arithmetic circuit for performing interpolating operation based on two position signals read out from memory upon playback operation.

Abstract: A machine tool provided with a movable table supported by a stationary table, the movable table being displaceable relative to the stationary table in all directions and being supported by the stationary table by pressurized fluid bearing. The movable table is positioned by at least three actuators pivotally connected at one end to the stationary table and at their other end to the movable table such that the lengths of the actuators, controlled by an appropriate numerical control system, result in a predetermined position of the movable table relative to a reference position.

Abstract: A mechanical element is moved from a first position to a second position along a vector path. Individual step controllers provide drive along each axis at respective velocities for vector movement. The velocity along the greatest distance axis is the master against which acceleration and velocity of the other axes is measured. Optional closed-loop operation insures synchronism of movement along the different axes.

Abstract: An automatic positioning apparatus comprises a smoothing means. The smoothing means is adapted to connect smoothly a 3-dimensional path based on the preceding and succeeding four taught points irrespective of a straight line or a curved line, while correcting a driving system with a delay of a system of a means being controlled, thereby to achieve a control in consideration of not only inertia but also a response characteristic.

Abstract: Serving to control at least two pulse-controlled drive means for moving a tool along respective coordinate axes, the control system comprises input means for presenting workpiece data and tool data; an arithmetic unit for processing said workpiece data and tool data presented by said input means and for providing section end point data which are related to said coordinate axes and define section end point positions of said tool on a path along which the tool is to be moved by said drive means; clock means operable to produce clock signals at a plurality of clock frequencies; and interpolating means arranged to receive said section end point data and clock signals and to deliver speed control pulses to each of said drive means to cause said drive means to move said tool between successive ones of said section end point positions along path sections having predetermined configurations.

Abstract: A robot is disclosed having a robot manipulator, detectors for detecting the positions between each of the movable members of the manipulator, a memory unit for successively storing positional signals supplied from the detectors upon teaching operation, interpolating operation circuits for executing interpolating operation based on two positional signals which are read out from the memory unit in order to determine required number of positions between the two positional signals thus read out upon playback operation, and servo circuits for positioning each of the movable members of the manipulator by the operation result signals from the interpolating operation circuits.

Abstract: A plurality of pulse motors (225X, 225Y, 225Z) can rotate driver devices (222X, 222Y, 222Z). The driver devices are fitted in the parts of, for example, a horizontal oscillation circuit, a vertical output circuit and a power source circuit of a television circuit, which are formed on a printed circuit board (220). The outputs of the horizontal oscillation circuit, vertical output circuit and power source circuit are supplied to a digital frequency counter (223X), a first digital voltmeter (223Y) for measuring vertical amplitude and a second digital voltmeter (223Z) for measuring power source voltage, respectively. They are converted into digital data.The output data of the digital frequency counter (223X), the first digital voltmeter (223Y) and the second digital voltmeter (223Z) are compared with predetermined data at digital comparators (224X, 224Y, 224Z), respectively.

Abstract: A machine tool and its associated control system has workpiece holding me which are mounted on a frame for rotation about a fixed axis and are adapted to support and to be fixedly connected to a workpiece, such as a crankshaft, centered on that axis. The machine tool further has a tool carriage which is slidably mounted on the frame for displacement in a direction which is transverse to the rotational axis; first drive means which serve to impart angular rotation to the workpiece holding means about the axis; second drive means which serve to displace the tool carriage in the transverse direction; and electronic control means for controlling the first and second drive means so that the desired angular rotation and transverse displacement are performed with a predetermined, generally nonlinear relationship to each other.

Abstract: In a system which calculates a digital quantity at known time intervals and converts the calculated result to analog form to apply a command, for example, to a numerical-controlled machine tool, there is provided a circuit which obtains a difference value between current and previous calculated results and outputs a value obtained by dividing the difference value by N, and an adder which adds the output from the dividing circuit to the previous calculated result at time intervals of 1/N of the known time interval. The added result by the adder is converted to analog form at time intervals of 1/N of the known time interval to issue the command; as a consequence, the command does not change abruptly but undergoes a smooth change, eliminating the possibility of a great shock being imparted to controlled equipment, for example, a numerical-controlled machine tool.

Abstract: A control system for an automatic machine or robot having an articulated arm, comprising position transducers for sensing the position of the arm, actuators for effecting displacement of the arm and a mini-processor which receives signals from the transducers and feeds signals to the actuators, the mini-processor including a memory in which are stored digital data representing the movement of the arm, the stored data being memorized by the mini-processor at a selected frequency depending on the movement of the arm in a learning mode of operation of the machine, this selection being effected cyclically by sampling the transducer signal at a plurality of different frequencies and then calculating for each sequence of signals sampled at a frequency lower than a maximum frequency the values of the signals at points, interpolated between the sampled points, which would have been sampled at the maximum frequency: the calculated values are then compared with the actual sampled values at the maximum frequency and the

Abstract: In a numerically controlled machine includes a first computer which stores command data for a path and derives sets of interpolation point data from said command data for a plurality of points along the path. A second computer stores two sets of interpolation point data from said first computer and extrapolates a set of said stored interpolation point data by incrementing velocity with acceleration and position with velocity using a noncircular high order polynomial to produce a sequence of driver command signals.A timing means provides timing signals to the second computer to determine the number and rate of iterations of drive command signals in said sequence as predetermined by the first computer for each set of interpolation point data.The program execution time in the second computer is reduced by a unique method of multiprecision calculation which requires a carry flip flop for each variable calculated and a sign flip flop for eliminated word segments.

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: 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: The coordinates (X.sub.n+1 Y.sub.n+1) of an arc to be traced at time t.sub.n+1 are preliminary calculated using the coordinates (X.sub.n Y.sub.n) at time t.sub.n, the radius (r) of the arc and a specified length l.sub.n during the time t.sub.n+1 -t.sub.n, thus the number of the calculations required for tracing an arc is considerably reduced and a low speed digital element which is cheap can be utilized in the present arc interpolation system. The formula for obtaining the coordinates is;X.sub.n+1 =X.sub.n +Y.sub.n .multidot.l.sub.n r-X.sub.n .multidot.l.sub.n.sup.2 /2r.sup.2Y.sub.n+1 =Y.sub.n -X.sub.n .multidot.l.sub.n /r-Y.sub.n .multidot.l.sub.n.sup.2 /2r.sup.2The asymptotic change of the above formulae and the apparatus according to the asymptotic formulae is also possible.

Abstract: The present invention discloses an arrangement wherein a wall thickness of a plastic bottle formed by means of a blow-molding process is formed into the desired configuration by controlling the wall thickness of a parison from which the bottle is made. A control pin arranged opposite an extrusion outlet of an extruding machine for adjusting the wall thickness of the parison is finely moved in response to a fine step-like control voltage signal to thereby suitably set and vary the opening degree of the extrusion outlet of the extruding machine, thus obtaining the desired wall thickness for the parison.

Abstract: In path control apparatus for a numerically controlled machine tool, a computer determines the trajectory to be traversed in space, resolves the latter by way of interpolation into the axial increments of the individual feed axes and performs complete position control for each axis. The interpolation is accomplished by the method of direct function computation, using travel distance increments proportional to the trajectory velocity. The position control is designed as a discrete control and operates with the premise that the minimum total computing cycle time is shorter than the sampling time of the fastest position control loop required by the control system.

Abstract: A numerical controller having a memory device for storing a profiling program composed of a series of data blocks, each of which designates an incremental rotational amount of an oval workpiece and an incremental feed amount of a tool slide, and a digital computer for reading out the data blocks one by one from the memory device when no rough grinding is instructed, so as to provide, based upon a read-out data block, interpolation data of feed pulses which are to be distributed for tool slide feed in connection with feed pulses to be generated for workpiece rotation. In rough grinding, the digital computer reads out a predetermined number of the data blocks and accumulates profiling data included therein so as to provide interpolation data based upon the accumulated profiling data, thereby shortening processing time for providing the interpolation data in rough grinding.

Abstract: The prior D.D.A. (Digital Differential Analyzer) having an integrand register, a remainder register and an adder for pulse interpolation has been improved by attaching some new units to the same, including a counter for counting the reference instruction pulses, a register for storing the content of the counter, and a multiplier for providing the product of the content of said register and the content of said integrand register. The product provided by the multiplier instead of the output of the integrand register, is applied to one input of the adder, the other input of which receives the output of said remainder register. Thus, the interpolation calculation has only to be performed once in every several periods of the instruction pulses, therefore, a slow speed digital element can be utilized for high speed instruction calculation.

Abstract: Control apparatus is provided to control a programmable manipulator having a manipulator arm movable in a plurality of axes to perform a predetermined pattern of work operations in a replay cycle with respect to a movable workpiece while the workpiece is moving or is stationary at a point along a predetermined workpiece path. In replay, the control apparatus generates interpolation control signals from stored data in accordance with the workpiece position. The stored data includes two or more series of signals representing manipulator arm positions to accomplish the predetermined pattern of work operations with respect to the workpiece at two or more respective positions of the workpiece.During replay, data is read out from the two series of signals that are associated with workpiece positions on either side of the present workpiece position.

Abstract: This invention relates to a computer numerical control (CNC) machine tool system having a novel terminal controller and system therefor to control a machine tool generally with at least two axes and more probably three, with stepping motor controls for point-to-point positioning of the machine tool to an almost infinite variety of steps (generally not more than 200). The novelty resides in the ease of programming directly on the terminal controller of the CNC machine tool system. Generally at least some editing and offsets will be programmed from the machine tool.The terminal controller consists of a microprocessor with some RAM and ROM, together with address and data bus plus I/O for magnetic tape handling and display for 6 to 8 digits in each of the X and Y positions, together with numeric keyboard for data input to the program steps and functional keys to control operation-automatic, manual and step-by-step, as well as controls for program input from tape to memory and memory to tape.

Abstract: A method and system of velocity control for an automatic welding apparatus, wherein at least either a welding torch or a workpiece is movable in the directions of the three rectangular axes and point-to-point (PTP) position control of the torch and workpiece is effected between two preset positions at a preset relative velocity. In effecting the PTP position control, the direction of movement is determined based on information about the two preset positions, and the components of the preset velocity in the directions of the three rectangular axes are determined based on the direction of movement thus found and also based on information about the preset velocity, these components being used as instruction velocities in the respective axes.

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 controller minimizes periodic torque or force perturbations in an inductor-type synchronous motor drive by supplying current waveforms to each motor phase that contain a fundamental frequency component and selected harmonic components. The harmonic components in the phase currents heterodyne with the periodic permanent magnet flux fundamental frequency to create periodic torques or forces which subtract from the unwanted torques or forces perturbing the moving portion of the motor. The controller, which includes an interpolator, a memory, and a converter, provides for smooth incremental movement of a member such as a plot head, at substantially constant velocity, by applying selected continuous periodic waveform signals as phase currents to the windings of inductor-type synchronous motors.