Abstract: A manipulator having a plurality of articulations to be controlled with a given destination value of position and orientation, has a finite difference unit for obtaining a finite difference between the destination value and a present value for each articulation, and a fuzzy inference determination unit for executing a fuzzy inference for each articulation by using the finite difference and determining a command value for each articulation. The position of the manipulator terminal may be obtained on the basis of each articulation angle data, video data from a TV camera, or data from an ultrasonic sensor.

Abstract: An NC statement preparing system of an interactive numerical control device. Whether a tool (2) is a one-way cutting tool or a tool capable of multi-directional cutting is determined, and an NC statement is prepared by choosing between an NC statement composed of a tool passage for the one-way cutting tool and an NC statement composed of a tool passage for the multi-directional cutting. Accordingly, a machining program for a short machining time can be prepared.

Abstract: A desired curved path is approximated by spline segments, which in their entirety define the path of motion for a machine-tool or for a robot. The deviation in position of this path of motion from the desired curved path is maintained within a specified tolerance band. Through an iterative process, the path of motion is formed with the fewest possible spline segments. If two many spline segments were used, they could overtax the processing speed of a numerical control system. But, on the other hand, the interpolation of spline segments is technically a relatively simple process.

Abstract: Disclosed is a synchronous control system for effecting a synchronous and superimposed operation among different channels of a multi-channel-control machine tool. A follow-up error amount (.epsilon.3) of a servomotor responsive to a superimposing instruction is simulated, a difference is determined by subtracting the follow-up error amount (.epsilon.3) to the superimposing instruction from a follow-up error amount (.epsilon.2) of a servomotor for a superimposed operation axis (Z2) and the difference is compared with a follow-up error amount (.epsilon.1) of a servomotor for a synchronous operation axis (Z1) to produce an alarm when the comparison indicates the operation of the servomotors is synchronized and superimposed.With this arrangement, a synchronous error can be checked when a superimposed operation of the servomotors is effected.

Abstract: A driving control circuit controls a robot in grasping a desired product positioned within an injection mould, safely moving the desired product to a predetermined place, and then returning the robot to its initial position. The circuit uses a plurality of relays, timers and sensors without the use of a computer system to mechanically operate the robot. The driving control circuit allows the robot to function using a general motor without the use of an expensive stepping motor standard in robotics. The elimination of the stepping motor reduces the manufacturing cost, thereby, improving industrial automation.

Abstract: A numerical control apparatus according to the invention for interpolatory control of a tool along the shape of a workpiece to be machined. In order to perform offsetting of a cutting tool by an amount equivalent to the tool diameter when involute interpolation is carried out, an involute curve is approximated by a circular which is set in dependence upon the intersection angle of a machining trajectory at a command point commanding the start of machining.

Abstract: The method of controlling a mechanical hand includes releasing the head in its initial position, moving the hand to its target position and retaining the hand in its target position. With the hand moving towards its target position, the path of its travel is divided into a portion registering the parameters of its motion and a portion correcting the law of its motion. With the hand moving over the registering portion, a reference voltage is supplied to the drive motor, and the speed and running coordinate of the moving hand are measured and registered. With the hand moving over the correcting portion, its speed is measured, and the difference between the speeds measured at the two portions is computed to shape an additional voltage. A voltage is then fed to the drive motor, which is an algebraic sum of the reference voltage and additional voltage.

Abstract: A method and apparatus for controlling the tracking path of a working element so that the working element moves along a path having a predetermined positional relationship with a working object by adjusting the relative positional relationship between the working element and the working object through the movement of individually movable at least one moving element.

Abstract: A multiple-degree-of-freedom manipulator having a plurality of joints is improved by providing some of said plurality of joints being provided with holding brakes, and providing any remaining joints with actuators which generate angular acceleration or linear acceleration in the joints provided with holding brakes while the holding brakes of the joints are released. A method of controlling the multiple-degree-of-freedom manipulators provided with one or more joints provided with holding brakes and one or more joints provided with actuators, comprises the steps of controlling the angular displacement or linear displacement of joints which have no actuators by the torque or force of joints which have actuators by means of the dynamic coupling between joints while the holding brakes are released, and controlling the angular displacement or linear displacement of joints which have actuators by means of the actuators while the brakes are engaged.

Abstract: A robot system in which a force (torque) exerted on an end effector disposed at an end of a robot to hold an object is sensed to achieve a positioning control. The robot system includes a unit to sense an inertial force exerted on the end effector and the sensed result is fed back so as to remove the influence of the inertia force, thereby effecting an accurate positioning control.

Abstract: Disclosure is made of a system for remote transmission of the angular position and force between the master and slave shafts, which includes master and slave synchronous machines (1,2) whose shaft position sensors (9,10) are electrically connected to inputs (11,12) of a unit (13) for assigning orientation of stator magnetic fields of the synchronous master and slave machines and to information inputs (15,14) of a device (16) for assigning the amplitude of stator magnetic fields of master and slave synchronous machines, having its output electrically connected to a control input (21) of a unit (22) producing current in the windings of the synchronous machines, having its setting input (23) connected to the output of the unit (13) for orientation assigning. The outputs of the producing current unit (22) are connected to electrically linked respective windings of the synchronous machines (1,2).

Abstract: A digital servor system can swiftly stop a moving object, having a small friction resistance to the motion, at the position where the object should stop, without vibration thereof. A velocity command generating device (3) calculates a velocity command (V.sub.cmd) based on the deviation value of a position fedback from a position command detected by a position deviation detecting device (2). A velocity deviation detecting device (5) calculates a deviation (E) of a velocity fedback from the velocity command (V.sub.cmd). A torque command generating device (6) calculates a torque command (T.sub.cmd) giving a delay processing to the deviation (E), and outputs the torque command (T.sub.cmd) to a motor driving means (7).

Abstract: A numerical control method and an apparatus therefor, in which a mold opening operation or an eject operation is performed during a metering operation so that the injection-molding cycle time is shortened. When a cooling period terminates or mold opening is completed during the metering operation, a programmable machine controller for sequentially controlling an injection-molding machine delivers information specifying a clamp axis or an eject axis, the displacement, moving speed, and moving direction of the axis, and a step feed command to a numerical control unit for controlling servomotors for axes of the injection-molding machine, through a common RAM. Pulse distribution for the clamp axis or the eject axis, based on this information, and pulse distribution for a screw rotating axis are alternately executed by a numerical control unit, which responds to the step feed command.

Abstract: This disclosure describes a method and associated apparatus, in the manufacture of flat tension mask cathode ray tubes, for detecting the edges of a mask receiving surface in a plane, identifying its coordinates and subsequently delineating the path of an attachment device for permanently affixing a tensed foil shadow mask to the mask receiving surface of a mask support structure.

Abstract: A method of positioning a tool along a circular arc. The tool is carried by an automaton which is moved through a teaching phase during which it is taught coordinates and wrist orientation angles for three reference points. The method then proceeds into a work phase in which calculations are performed to determine coordinates and wrist angles for a series of work points spaced along the circular arc defined by the three reference points. Thereafter the automaton is direction to position the tool at the calculated coordinates and orientations.

Abstract: A digital robot control employs planning and trajectory programs which generate the trajectory plan and trajectory position commands with the use of an acceleration profile and a deceleration profile selected from at least square wave and sine wave profiles.

Abstract: A groove is milled along a predetermined line using a cutter (2) mounted at the end of a rotary shaft (3) which is displaced under computer control (A) via a control interface (B) in such a manner as to ensure that its axis X.sub.4 remains constantly substantially perpendicular to the wall of the tube and that the depth to which the cutter penetrates into the thickness of the wall is under constant control.

Abstract: A completely digital robot control operates at a predetermined sampling rate. The robot arm has a plurality of joints with each driven by an electric brushless or brush-type DC motor which is in turn supplied with drive current by a power amplifier bridge circuit having power switches connected therein to supply motor winding current in the forward or reverse direction.Incremental or absolute encoders and tachometers provide for generating digital position and velocity feedback signals generated synchronously with the sampling rate. Digital motor current feedback signals are also generated synchronously with the sampling rate.Paired position/velocity microprocessors generate torque commands for each of the robot axes at the sampling rate in response to the position commands and the position and velocity feedback signals. Paired torque microprocessors generate motor voltage commands for each of the robot axes at the sampling rate in response to the torque commands and the current feedback signals.

Abstract: A numerical control system has a tool holder which supports tools . . . attached to at least two intersecting sides, preferably three sides of a rectangular shape. The tool holder is movable along plural axes, e.g., X and Y-axis directions. A memory circuit is provided for storing the positional data regarding the tips of the tools and a workpiece diameter when the tool holder is predetermined reference points. When a workpiece is to be machined by a selected tool, the data regarding the selected tool and the workpiece diameter are called from the memory circuit, the distance from the tool tip to the outer periphery of the workpiece is computed, and the tip of the tool is moved to the outer periphery of the workpiece. With this arrangement, tools can be changed quickly.

Abstract: A digital control for a robot having a plurality of arm joints includes an electric motor for driving each of the robot arm joints and a power amplifier operable to supply drive current to each motor. Pulse width modulators generate digital control signals for the power amplifiers.Feedback control loop means for each joint motor includes at least position, velocity and torque control loops operable to control the associated power amplifier. Motor position, velocity and drive current feedback signals are generated for the control loop means for all of the robot axes.A position/velocity microprocessor control executes a planning program to generate a time profile including acceleration, slew and deceleration time segments for implementing each commanded robot program move.

Abstract: A numerical control apparatus is disclosed by which tools are controlled concurrently with respect to their translations in the X-axis, the Y-axis, and the Z-axis in synchronism with or independently of each other. The numerical control apparatus comprises a memory region for storing the translation axis data; a memory region for storing the distance data; a memory region for storing synchronous-translation velocity data; a memory region for storing independent-translation velocity data; and a memory region for storing independent-translation axis data.

Abstract: A circular path control apparatus and method for a multi-axis servomechanism having a plurality of driving shafts. Any disturbance to a command circular path is calculated from the amount of contour error of a circular path or a square of a circular-arc center angle error and a control for cancelling the disturbance is added, thereby improving the circular path accuracy of the multi-axis servomechanism.

Abstract: A playback system grinding robot is disclosed which includes a No. 2 arm attached for ocillation to the head of a No. 1 arm turning around a main axis, a drive arm arranged adjacent to the No. 1 arm so as to drive the No. 2 arm, and abrasive tool attached to the No. 2 arm head axis and pressed perpendicularly downward by a fluid cylinder to be freely turnable in different directions, and possessed of a dual degree-of-freedom of control in the polar coordinate system. A positional data generator for indicating a horizontal movement position of the abrasive tool is also provided as is a memory to store directional data together with positional data in the memory at the time of "teaching", especially to input turnback point data on the tool traveling locus exactly into the memory in accordance with a change of the directional data.

Abstract: A method of controlling a welding robot substantially comprises (i) teaching three points in the neighborhood of a teaching line to define a weaving pattern, and (ii) controlling three basic axes of a welding robot so that a welding torch tip of the robot moves on one of the surfaces of a triangular pillar formed by shifting a triangular plane defined by the above three points along the teaching line, while executing a weaving operation which is determined by a weaving amplitude, a weaving frequency, and a welding velocity. After continuing the above movement until the torch tip arrives at the end point of the teaching line, the weaving operation along the next teaching line is effected utilizing a new triangular plane which is formed by rotating the former triangular plane on an axis defined by the former teaching line and the next teaching line.

Abstract: A real time steering capability is provided to permit robot motion to be modified continuously in three dimensions as the robot is moving along a taught path. An arc welding robot or other taught path robot has a sensor located on the robot arm to sense the position of a desired path. The tracking control provides real time steering commands to the standard robot taught path and are calculated based on maintaining a constant, preprogrammed velocity along the desired path and coordination with the taught path. Offsets to the robot taught path are computed in a manner that allows the robot to smoothly follow the actual path as measured by the look ahead path sensor. The offsets are determined as separate x, y, z and twist integrations for the end effector and represent the total deviations from the robot taught path.

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 for effecting a weaving-like movement of a hand of an industrial robot, which hand is moved along a principle line while undergoing the weaving-like movement with respect to the principle line. Reference weaving-like pattern information stored as coordinate values in a predetermined reference coordinate system is transformed into actual displacements of the hand with respect to an actual moving direction thereof according to a hand attitude vector and a hand moving direction vector.

Abstract: A method of flank milling complex surfaces comprising the steps of analyzing the design surface to determine discrete areas in which straight lines can be drawn, determining straight lines in the discrete areas, transposing the coordinates of these straight lines and comparing them with the flank tool cutter positions, determining the tool positions to said straight lines, back generating the contact lines of said surface and comparing these with the design surface, determining the number of passes of said cutter tool and generating data for numerical control machining.

Abstract: A pen-lift system is provided which can achieve high speed plotting while maintaining line definition of drafting quality. The system includes a pen-lift mechanism for raising and lowering the pen, a pressure control system in order to provide a constant pen force for different kinds of pens, a velocity controller for varying the vertical velocity of the pen in response to changes in platen height and relative lateral pen position, and a position controller for sensing the present pen height relative to the platen and for actuating the pen-lift mechanism to achieve the desired pen-lift heights for different plotting situations.

Abstract: A device for positioning a semiconductor substrate is provided comprising magnetic field group formed from a plurality of magnetic fields disposed on a plane in a two-dimensional array. The magnetic fields are provided with a perpendicular orientation relative to the plane and adjacent magnetic fields are directed in alternate directions. Coil sets are formed of a plurality of coils, the coils having a specific dimensional relationship with the magnetic field array. Coil groups are formed by fixedly securing a plurality of these coil sets to each other the coil groups being disposed within the magnetic field group so as to be freely movable along the plane. Electric current is applied to the coils which generates a force in each coil set so as to move the coil set in either one of the longitudinal and lateral directions of the array of magnetic fields, whereby a current-motion converter and a driving device making use of the converter can be formed.

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: An apparatus and method are provided for controlling the motion of a point associated with a function element carried by a machine. The motion describes an oscillatory pattern in a selectable plane through a path between two positions defined by input signals. The oscillatory motion pattern defines cyclic excursions about the path. Motion is effected by iteratively interpolating intermediate positions along the path, computing incremental excursion amplitudes associated with the intermediate position displacements, calculating coordinates of the intermediate position excursions and producing machine actuator control signals to move the machine members to advance the point from its position along the pattern to an intermediate position.

Abstract: A valve seat (28) having a generally saddle-shaped, eccentric surface (52); a groove (50) of constant depth and width formed in the eccentric surface, having sidewalls (70) perpendicular to the eccentric surface and a base (72) parallel to the eccentric surface; and a flexible O-ring (54) retained by friction within the groove. The groove sidewalls and base have a surface finish in the range of about 32 to 125, which provides sufficient smoothness to retain the O-ring in the required non-planar shape.The valve seat groove (50) can be produced according to the disclosed method, which is preferably implemented in a numerically controlled four-axis horizontal milling tool system. The valve seat part (100) is mounted in a fixture (102) on a rotary table (104) such that the part axis (56) is aligned with the longitudinal axis (Z) of the tool (106).

Abstract: In a control device for an industrial articulated robot, in the linear interpolation between two specified points, the distance between the two points is divided into segments, and the interpolation increments of the articulation drive axes for each interpolation internal, which correspond to the segments, are calculated for interpolation so that the interpolation increments are distributed uniformly with time.

Abstract: An articulated manipulator and control are provided for producing controlled motion of a function element carried by the manipulator. The motion is defined by input signals specifying with respect to a rectangular coordinate system the positions and path velocities therebetween of a tool centerpoint associated with the function element. The control interpolates intermediate points along a predetermined path between any two positions. The intermediate points are produced in accordance with a fixed period interval and incremental velocity values instantaneously variable with each interval. Continuous functions of acceleration and deceleration are produced to vary the velocity in accordance with the programmed description of motion. Further velocity adjustment is permitted in accordance with unprogrammed variations of a preselected parameter.

Abstract: A feedback system for a robot controller provides feedback signals representing incremental motion along an axis in either a first or second direction based upon a pair of encoder signals from a position encoder. The feedback system includes circuitry which produces a pair of signals indicating the state of the first encoder signal and whether the first encoder signal has changed state, and circuitry which produces a pair of signals indicating the state of the second encoder signal and whether the second encoder signal has changed state. A read only memory receives these four signals at its address inputs and produces the first and second feedback signals at its data outputs based upon stored microcode. The encoder signals may be in the form of pulsed up/down feedback, where one of the two encoder signals contains pulses and the other encoder signal remains unchanged.

Abstract: A drafting machine which employs two variable speed and one constant speed motors. A pencil is moved along both X- and Y-axes by means responsive to the speed differentials of the motors. Speeds of the motors are controlled by an electrical circuit having a plurality of off-on switches and a plurality of rocking switches. The latter load counters from a pulse generator into counters for straight line, circle, spiral and logarithmic spiral controls which control activation of resistors which govern the speeds of the two variable speed motors. Indicators indicate to the operator the direction in which the pencil is moving, the diameter of a circle being drawn, the increment (or decrement) of a spiral being drawn as compared with a circle and the increment (or decrement) of a logarithmic spiral being drawn as compared with a spiral.

Abstract: A tracking type welding apparatus wherein a torch follows a probe along a weld seam and the probe senses lateral seam deviations and stores them in a pin cam and wherein the deviations are later used to move the torch in the same manner. The pin cam is remote from the torch and probe assembly and is electrically synchronized with it. Means are also disclosed to permit a single pin cam wheel to store horizontal and vertical deviation information and gap width information simultaneously.

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 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: An articulated robot arm (10) comprises n arm sections (13, 16, 18, 21) pivotally mounted one to the other. A plurality of independently controlled servomotors (12, 14, 17, 19) at each of the arm joints moves the tip (22) of the arm towards the desired location. All arm angles are measured with respect to a common reference plane, e.g. the horizon.

Abstract: A position control system for a welder includes a probe pivotably supported on the welding head assembly for motion through an arc extending ahead of the path of motion of the welding head. A sensor supported on the probe connects to a control system which generates an output representing coordinates of points along the center line, and an output proportional to the gap of the line of abutment between a pair of plates to be welded and controls the direction and rate of motion of the welding head along the center line of the abutment as well as the rotation of the head to maintain it in a proper disposition to the seam being welded and to maintain the sensor motion generally in front of the path of motion of the head.

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 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 method and apparatus for moving a device, such as a robot arm, through complex movements. The complex movement is divided into a principal movement between two defined end points A, B. Superposed on the principal movement is a closed loop series of subordinate movements (at least two subordinate movements) which loop is executed, at least once, during the principal movement. Data defining the end points of both principal and subordinate movements is stored in a storage device. Both principal and subordinate movements are divided into a number of equal incremental principal and subordinate movements. The sum of the principal and subordinate incremental movements is a composite incremental movement. Signals related to each composite incremental movement are provided to a drive means for moving the device.

Abstract: The invention discloses a digital position instruction signal modification device for use with a memory controlled manipulator apparatus of the type in which, during a teaching operation, a desired position of manipulator arm means is stored in memory means, and the stored position is read out during repetitive work cycles to cause the manipulator apparatus to reproduce a series of motions taught during the teaching operation. The digital position instruction or command read out from the memory means may be modified by a modifying value entered by a modifying value setting device so that all or desired digital position command or instruction signals stored in the memory means may be modified without repeating the teaching operation.