Abstract: The performance of prior automated welding systems has been limited by their inability to independently track and weld and by their inability to accurately determine the groove profile. The adaptive welding system disclosed herein includes a weld torch (20) adapted to be controllably positioned in at least two dimensions, and means (28,38) for tracking a workpiece seam (12) to be welded. The tracking means (28,38) is pivotably connected to the weld torch (20). Means (19,40) for pivoting the tracking means (28,38) relative to the weld torch (20) is included to permit both the tracking means (28,38) and the weld torch (20) to be independently maintained over the seam (12). The tracking means (28,38) monitors the seam (12) by optical triangulation of a rotating laser beam (60) projected against the workpieces. This rotating laser beam (60) crosses the seam twice during each cycle of the beam (60).

Abstract: An arc welding system with image acquisition utilizing a non-planar beam of electro-magnetic radiation, such as, a hollow conical beam of light, to illuminate at least a portion of the welding object is disclosed. The conical beam of light is generated by impinging a light beam on the surface of a concave, cylindrical reflector having a longitudinal axis that preferably is parallel to the longitudinal axis of the welding torch. The light beam enters the concave cylindrical reflector through the hollow shaft of a motor. Rotation of the motor angularly positions the reflected light beam on the welding object. The illuminated portion of the object is imaged on an array of photosensitive elements to produce corresponding signals that are representative of the image on the array. These signals are used to obtain identification information concerning the welding object and guidance information for a plural axis manipulator that guides the welding torch tool along a welding seam.

Abstract: The invention pertains to a welding system having automatic groove tracking and adaptive groove filling capabilities. Data produced by a coordinated laser spot projector (10) and TV-scanner (12) combination is determined to an Intel 8085 computer (28) to provide a substantially continuous analysis of groove locations in a three-axis coordinate system as well as groove depth and area. Location information is fed to an LSI-11 computer (38) to control the tracking function through coordinate axis servo-type drives (46) and to control a fourth-axis or "swing" function which provides freedom between the welding torch (14) and the optical system (10, 12) which leads the torch by several inches. The groove depth and area information is also fed to the LSI-11 to control the welding parameters, i.e.; deposition rate and voltage and produce the desired weld along the groove.

Abstract: A scanning angle tracker which includes a laser beam and a beamsplitter for developing two beams which intersect on a scanning mirror. The scanning mirror sweeps the two beams across a retro-reflective tape on the object. Return signals are generated for processing to provide the desired angular information.

Abstract: Structured light patterns are introduced into the arc vicinity within the field of view of the integral optical sensor on a gas tungsten arc welding torch. Processing the image yields data needed to guide the torch and control and assess the weld process. The optical welding torch has a projector system with a remote light source and flexible fiber optic bundle over which the light pattern passes to an exit projection and relay assembly mounted on the torch. A programmable laser pattern projector, useful for other applications, has a beam deflection device that traces a two-dimensional pattern on the entrance of a coherent fiber optic bundle; no moving parts or electrical connections are needed at the terminal end. An optional modulator changes the pattern intensity spatially or temporally.

Abstract: An optical pattern tracing system of the type having a tracing head with a scanner that projects a photocell onto a pattern in a closed path and provides two signals for each complete path across a line with an approach control for driving the tracing head toward the pattern-line that permits the operator to preselect either clockwise or counterclockwise tracing. The tracing head approach control includes circuitry that selectively blocks the first or the second pulse from the photocell and then terminates the blocking function shortly after the line is reached. An improved line detector is also disclosed that detects the true center of the line to be traced, and a dual pulse detector is also provided that assures that the scanner is fully locked onto the line prior to switching from manual to automatic control.

Abstract: A method of controlling an operation of a copycutting apparatus including a tracer for tracing automatically a pattern and a cutting gas torch interconnected to the tracer in a given relationship. Prior to the actual working, the tracer is manually moved with respect to the pattern along a given path and stores coordinates of operational points such as a piercing point, a copy start point, a copy end point, an intermediate point, a slow down point, etc. During the actual working the stored coordinates are readout to control the movement of the tracer in such a manner that until the tracer does not reach a copy start point the copying apparatus is set in a position setting mode in which the tracer is moved under the control of the readout coordinates. After the tracer has reached the copy start point the copying apparatus is switched into a copying mode in which the movement of tracer along the pattern is controlled by detecting the pattern.

Abstract: A method of controlling the operation of a copying apparatus which includes a tracer for tracing automatically a contour of a pattern to be copied and a working machine arranged in conjunction with the tracer in a given relationship is disclosed. At first, the tracer is moved manually with respect to the pattern to be traced to detect point data such as a working start point, a copy start point and a copy end point, and then automatically moved along the contour of the pattern to detect pattern data, while the working operation is performed. Next, the thus detected point and pattern data are stored in a cassette tape. Therefore, in case of performing the repetitive working operation for the same pattern, since the working operation can be performed in accordance with the data read out of the cassette tape, the required working operation can be effected in a simple and rapid manner.

Abstract: A method for tracing an object such as an outline of a picture or a line image, wherein the object is sensed by a set of sensing elements arranged in an optical head moving along the object, to detect a position and a direction of the object, wherein the optical head is controlled to trace the object depending on the detected position and the direction of the object, and wherein the object is reproduced by reproduction means which is moved in synchronization with the optical head. Present invention improves this method by moving the optical head along portions of the object, which the sensing elements can discriminate hardly or not at all nor follow the object, according to line segment data which is predetermined and represent a plurality of points of coordinates.

Abstract: In an X-Y addressable workpiece positioner the workpiece to be positioned, such as a semiconductive wafer to be aligned with a mask image, is coupled to move with a work stage moveable in the X-Y direction and having a two-dimensional array of positioning indicia affixed thereto for movement therewith. An enlarged image of a portion of the positioning array is projected onto a relatively stationary sensor stage to derive an output determinative of the X and Y coordinates of the positioning array relative to the position of the sensor. The sensed X and Y coordinates of the positioning array are compared with the X and Y coordinates of a reference positioning address to derive an error output. The work stage is moved in response to the error output for causing the workpiece to be positioned to the reference address.

Abstract: In order to track a distinctive line on a workpiece area to be followed by an operating implement, specifically a junction line between two workpieces to be welded by a torch advancing along that line, a narrow beam is trained generally perpendicularly from a pulsating source of luminous radiation--e. g. a laser--upon that area and is shifted parallel to itself around the implement so as to intersect the workpiece area along a closed trace substantially bisected by the line being tracked. The source of radiation is part of a photosensor including an objective with an optical axis inclined to the beam at a small angle to generate an image of the latter on a slanting straight line parallel to a central ray which passes through the point of intersection of the beam axis with the front focal plane of the objective, this image line starting at the intersection of the rear focal plane with a central ray parallel to the beam.

Abstract: An apparatus for controlling positioning of an implement relative to a workpiece, such as a welding head with respect to members to be welded, projects light patterns including an array of light elements each having a known shape and spacing relative to one another on the workpiece. The light elements as reflected from the workpiece are detected and output signals produced in response to the detected light elements. The output signals are classified into groups based on at least one common characteristic resulting from workpiece geometry. The workpiece geometry is defined from at least one relationship between different ones of the groups of the first output signals. Second output signals are produced indicative of the so-determined workpiece geometry. The second output signals are used to control positioning of the implement relative to the workpiece. This apparatus and process allows workpiece geometry to be defined and the implement to be positioned relative to the workpiece on a real-time basis.

Abstract: An optical pattern tracer is disclosed, of the circular scanning type. The interception of the pattern by the scan produces electrical outputs which are reduced to numerical values representative of their time of occurrence with reference to the scanning circle. The numbers derived and the nature of the signal generated are then processed to indicate the direction of the pattern, presence or absence of command marks and combined with other reference inputs, such as kerf and direction of tracing used to control a drive mechanism to move the tracer around the pattern.

Abstract: A method for recording and reproducing information characterized in that an information train in which synchronizing signals are arrayed at equal time intervals between information signals is recorded in an information track on a recording medium which is wobbled in synchronism with the synchronizing signals and at a frequency integral times the frequency of the synchronizing signals, that the information train recorded in the information track is read out by read-out means, and that a position of the read-out means is controlled on the basis of the information train read out. The wobbling waveform is 90.degree. out of phase with a harmonic component of the synchronizing signals.

Abstract: A window generation circuit is provided for gating image signals from an electronically scanned sensor array in a line tracing machine. The window generation circuit includes two shift registers of variable length for measuring intervals of time for setting first and second bounds to a sector scan. The interval of the second register corresponds to the width of the window. Logic circuitry, responsive to the detection of image data, alters the electrical lengths of the registers to enlarge the window in the absence of an image, and restores the original lengths upon return of the image.

Abstract: An optical scanner for a pattern tracing system for scanning an irregular two-dimensional pattern using an optical beam deflection principle. A scanning head is non-rotatably mounted above the pattern on a frame moveable in two coordinate directions. The scanning head reflects an image onto the pattern by a pivotally mounted mirror in the scanning head and is deflected at high frequency in two normally orthogonal planes by the interaction of a pair of perpendicularly related electromagnets with a permanent magnet. The geometric axis of the mirror nutates around a scan axis to provide a generally circular scan image on the pattern. The axis about which the mirror nutates, referred to as the scan axis, is shiftable from a fixed reference axis to achieve offsets for the scan image to provide both forward offset and "kerf" offset perpendicular to the forward offset. A control circuit derives out of phase alternating signals for the two scanner coils to cause this nutational motion of the mirror.

Abstract: Eccentricity control apparatus is provided in a system for optically recording and reading information on a rotating disc medium. The information may be recorded on concentric or spiral tracks. The eccentricity control apparatus includes a detector for detecting track crossings as an optical scanning head scans the disc surface. The detector provides pulses representative of track crossings. The number of pulses in a once-around is representative of the amplitude of an eccentricity control signal. The angle measured between a once-around pulse and a minimum pulse rate of the track crossings indicates the phase of the error. An eccentricity error signal which is generated by suitable circuitry is applied to affect the manner in which the optical scanning head scans the disc surface such that number of track crossings is reduced.

Abstract: The invention concerns an automatic welding apparatus for plates. A regular reciprocatory scan is carried out by an optical sensor 18 of the joint 32 between two plates 28 and 30 to be welded: the sensor 18 moves transversely of the general direction of the joint to be welded which moves past under the welding torch 10 and under the sensor 18; the time interval between the instant when the joint is sensed and the instant when the sensor passes the axis of the torch is measured and the torch is moved transversely, by means of a motor 15, in response to the measurement of the time interval, in a direction corresponding to a reduction in this interval, so as to recenter the torch on the joint 32 to be welded. This arrangement avoids drift and possible disengagement from the joint which can occur in welding processes with continuous following of the joint.

Abstract: Apparatus for cutting a metal workpiece including pipe in any desired shape and in a cutting cycle governed by a numerical controller having a plurality of separate output control signal channels. The apparatus is highly versatile and automatically operable to cut any preselected contour in accordance with control or program instructions carried on a control tape. In an illustrative embodiment of the cutting apparatus, a metal cutting torch is supported on a first support and the workpiece to be cut is mounted on a second support so arranged relative to the first support that the relative movement between the workpiece and the torch allows a cut to be made along X and Y axes at right angles to one another. The cutting torch is power driven about its own longitudinal or W axis by a reversible motor and is power driven about a fourth or Z axis to vary the bevel of the cut.

Abstract: A method of controlling an operation of a copy-cutting apparatus including a tracer for tracing automatically a pattern and a cutting gas torch interconnected to the tracer in a given relationship. Prior to the actual working, the tracer is manually moved with respect to the pattern along a given path and stores coordinates of operational points such as a piercing point, a copy start point, a copy end point, an intermediate point, a slow down point, etc. During the actual working the stored coordinates are read out to control the movement of the tracer in such a manner that until the tracer has reached a copy start point the copying apparatus is set in a position setting mode in which the tracer is moved under the control of the read out coordinates. After the tracer has reached the copy start point the copying apparatus is switched into a copying mode in which the movement of tracer along the pattern is controlled by detecting the pattern.

Abstract: Apparatus for non-contact tracking of a weld seam to provide lateral position guidance of a welding torch advanced along the weld seam by a traveling carriage utilizes an electromagnetic radiation source for directing an unfocused beam onto the weld seam producing a spatial distribution of reflected electromagnetic radiation having an optical center of power the location of which is functionally related to the lateral position of the welding torch relative to the weld seam, and a lateral cell position sensor for sensing a shift in position of the optical center of power of the reflected electromagnetic radiation spatial distribution. Detection of a shift in position of the optical center of power is utilized as an indication of lateral deviation of the welding torch relative to the weld seam.The apparatus disclosed further includes signal processing circuitry that develops an electrical signal indicative of welding torch position for input to a torch drive servomechanism.

Abstract: Disclosed is an interactive graphic apparatus for obtaining a desired formal drawing from a manuscript bearing rough drawings depicted thereon. In this apparatus, the operator can automatically draw onto a drawing paper put on a drawing table, on the basis of the positional information items of drawings on a manuscript disposed on a reading table and the functional information items inputted from a key board. The apparatus has particularly three component elements of digitizer, controlling device and plotter incorporated into an integral desk-like structure and various operational functions, whereby the interaction of the apparatus is improved.

Abstract: An automatically guided vehicle wherein a guide line is positioned in a predetermined path on the floor and the vehicle has a sensing head positioned over the guide line to detect the position of the guide line with respect to the vehicle and to generate an error signal representative of the vehicle position with respect to the guide line. A control circuit is also provided on the vehicle to steer the vehicle responsive to the error signal generated by the sensing head. The sensing head includes a scanning head to scan across the guide line and to generate an output signal representative of the detected light values at discreet positions of the scan. The control circuit is adapted to steer the vehicle along the right edge, left edge or center of the guide line and is responsive to control codes positioned on the floor adjacent the guide line.

Abstract: A machine for tracing an outline of an original picture and recording the same outline image as the picture for making a cutting mask for photo-printing, which includes an optical head for receiving light from a light spot projected to the picture by a projector, detecting elements in the optical head which detect the outline of the picture and produce signals for controlling a driving arrangement, and a processing head for recording a locus of the outline onto the recording material, wherein the processing head has the same movement relative to the recording material as the optical head has relative to the original picture.

Abstract: An automatic machine for displacing a shaping tool, such as a router, over a work area includes a tool mounting assembly carried by support means such as an articulated arm. The arm is movable by first movement means relative to fixed structure of the machine over the whole work area, while the tool mounting assembly can be moved within a limited zone relative to the arm by second movement means. The movement of the tool mounting assembly (and thus of the tool) is directly measured relative to the machine fixed structure and compared with a required movement to generate an error signal. This signal is fed to the second movement means which endeavors to move the tool mounting assembly as required over the work area.

Abstract: A digital servo system for maintaining a detection device, such as a light beam, centered as closely as possible over an information track, such as an optical track on a video recording disc. The servo system includes circuitry for detecting when the light beam traverses a switching line, which, in the illustrative embodiment, is the track centerline, for applying a constant-magnitude acceleration force to deflect the beam to a corrected position, and for reversing the polarity of the acceleration force when the beam traverses the switching line.

Abstract: A digital servo system for maintaining a detection device, such as a reading beam, as nearly as possible centered with respect to an information track, such as an optical track on a video recording disc. In each of the embodiments disclosed, circuitry is provided to process a signal obtained from the reading beam, to obtain timing signals indicative of transitions of the beam across noncentral switching lines parallel with the track. In one embodiment, a constant-magnitude acceleration signal is applied to a beam position transducer, and is reversed in polarity each time a switching line is crossed after first crossing the centerline. In another embodiment, the polarity of the constant-magnitude acceleration signal is reversed after crossing a switching line a second time and after applying an additional acceleration impulse of relatively short duration.

Abstract: A numerically controlled stitching machine tool comprises a head and a ta movable in relation to each other along two coordinate axes. The head is provided with a stitching needle and an optical follower placed in an invariable position in relation to the needle and receives the image of a drawing of the pattern when the drawing is placed on the table. The machine comprises, for each coordinate axis, a motor for moving the head and the table in relation to each other along that axis, transducer means for supplying an electrical signal whose amplitude depends on the movement along this axis, for A/D conversion and non-volatile storage, means for controlling the motor from the stored signals bringing into action said transducer and conversion means.

Abstract: A system for guiding a tool according to a predetermined direction includes a detector head which photoelectrically scans a line of the pattern with the line varying in width at predetermined locations and with the output signals of the scanning photoreceptors being conductable to a switching device having an adjustable switching threshold so that when the scanning is in the area of the altered line width an auxiliary signal is formed in addition to the control signal for the coordinate motors.

Abstract: The line-trace to be read-out is illuminated by a light spot scanning radially from, and by rotation around, a center that it set near the line-trace to be read, the radial scan having its own scan frequency and the scan turning around the center at a specific frequency of rotation. A signal is formed corresponding to the contrast modulation between the line-trace and the surrounding background, which is processed to give a signal corresponding to the minimum distance between the scan sweep center and the line-trace, the latter signal being processed further to produce the co-ordinates needed for directing the servo-control means of a machine tool.

Abstract: A pattern tracer having provision for recognizing special markings on the pattern termed "command marks" and for recognizing at least two different kinds of commands to enable special control of the machine tool controlled by the pattern tracer.

Abstract: A circular scanning optical pattern tracer produces two impulses per cycle, one impulse in the forward direction and one in the reverse. Means are provided to utilize either one of said impulses selectively to cause the tracer to proceed in a given direction or reverse at will in accordance with the pulse selected.

Abstract: This disclosure deals with a line or pattern following system for use with a machine including first and second motors for moving a device in first and second generally perpendicular directions. The system includes an array of light sensitive elements arranged at angularly juxtaposed positions, the array being positioned adjacent said line or pattern. An image of the line or pattern falls on the array and makes an angle .theta. with a reference point on the array. The system further includes means for sequentially scanning the outputs of the elements, and angle means responsive to said outputs and to said reference point for generating first and second signals. The first signal is a function of sin .theta. and is connected to control energization of the first motor, and the second signal is a function of cos .theta. and is connected to control energization of the second motor.

Abstract: An analog of a path through which a cross slide table, for example carrying a workpiece or a tool is to be moved is traced on a drawing sheet. At points of change of direction or commanded speed of movement, graphic machine-readable symbols are placed on the drawing. A sensor, with sensing elements located in the quadrants of an x-y coordinate system, preferably secured to the cross slide itself, is placed above the graphic drawn representation of the movement path, the graphic representation is introduced by means of a program carrier beneath the cross slide and, upon recognition of symbols representing change of direction, speed of movement, suitable signals are derived which control servo motors moving the cross slide and the sensor in accordance with the sensed signals picked up by the sensor from the graphic representation of the movement immediately beneath the cross slide table itself, thus avoiding the necessity of numerical or other programmed input to the cross slide.

Abstract: A method for the formation of a comparison square wave signal having a reference edge in a curve control device in which a scanning head periodically transversely scans a line to be tracked and transmits a base comparison square wave signal and a measurement square wave signal whose phase position is a criterion for the divergence of the scanning head from the desired value, and is determined by comparison with the position of the base comparison square wave signal, whereby a follow-up signal is formed which is dependent on the direction of the divergence. The method comprises forming by frequency halving, integration and threshold means, needle pulses from the base comparison square wave signal produced by the scanning head, each successive pair of the needle pulses being completely symmetrical to the reference edge and wherein the comparison square wave signal is formed from the needle pulses and the reference edge.

Abstract: A curve-following device having an optical sensing head which senses a guide zone containing the guide line to be followed and having at least a substantial transverse component, and which is movable along the guide zone at a substantially slower speed than the sensing rate and is connected to a control instrument which forms, from the signals delivered by the sensing head, control signals for the movement of the sensing head along the guide line. Marks associated with the guide line and detectable by the sensing head are detected for tripping further control commmands. At least one separate code zone which is sensed separately from the guide zone is provided at the side of the guide zone.

Abstract: Disclosure is made of a system for automatic control of an object by a contrast program, which comprises the following components connected in series: an information scanner producing electrical signals whose combination carries information about the coordinate of the contrast program on the surface being analyzed, having a device for converting a specified portion of a radiation flux into an electrical signal carrying information on the contrast program and a reference signal generator producing electrical signals carrying information on the scanning of the analyzed surface; a unit for processing the electrical signals carrying information on the contrast program and on the scanning of the analyzed surface including a unit for forming normalized electrical signals carrying information on the contrast program and a logical circuit for processing the electrical signals carrying information on the contrast program and on the scanning of the analyzed surface producing electrical signals carrying information on t

Abstract: A photoelectric follower for following centers or edges of lines to control associated cutting torches produces a sharply-defined edge-of-line signal by making the `black` and `white` level signals of equal amplitude and opposite polarity. The follower has adjustable `lead` and a kerf width adjustment. Line scanning is effected by a piezoelectric rod.

Abstract: A curve follower device having an optical scanner head circularly scanning a guide region containing a guide line and a separate code region provided at least on one side of the guide region, the measurement point of the head being a predetermined distance from its pivot point in the direction towards the guide line, and the head being movable along the guide region at a speed considerably slower than the scanning speed and being connected to a control device which forms from the signals delivered by the scanner head, control signals for the movement of the scanner head along the guide line. In the code region marks associated with the guide line as detected by the scanner head are provided in order to initiate further control commands in the control device, the length of the marks being greater than the width of the guide line.

Abstract: Linear photosensitive array rotatably mounted in a digitizing cursor and maintained in an orthogonal relationship with the function (such as a curve or the like) to be digitized. As the cursor is moved along the function, the photosensitive array is maintained at right angles to the direction of the cursor movement. Circuits are provided to sense any difference in position between an indicium in the cursor and the function being traced, to obtain correction values to be applied to the digitized coordinates of the cursor position.

Abstract: An arrangement for cutting workpieces with a scanning device having a signalling photoresistor which detects markings, with an attached control device which contains a first timing element to which a switch for reducing the rate of speed is connected includes an OR-element connected between the first timing element and the switch with a further timing element connected by means of an AND-element to the input and output of the timing element with the input of the further timing element being connected to the output of the AND-element and the output of the further timing element being operationally connected to the input of the OR-element.

Abstract: Particular zones are given a distinctive appearance with respect to surrounding areas on a surface such as a printed-circuit board to be drilled in an automatic process. The surface is automatically scanned in a system of two rectilinear perpendicular coordinates by a reader comprising at least one detector which is responsive to the distinctive appearance. The coordinates of the surface points for which the detector delivers a signal representing the presence of the distinctive appearance during the scanning are recorded in a coded form which can be utilized by the automatic machine.

Abstract: A device for automatically controlling an electroerosion cutting machine in which a unit for selecting a direction of rotation of drive motors in the course of erosion working, includes a coincidence circuit and a reversible ring shift register whose outputs are connected to inputs of the coincidence circuit, whereas the latter's outputs are electrically coupled to coordinate drive motors which move an electroerosion tool relative to the workpiece, and an optical head relative to a coordinate follow table. The optical head is electrically connected to the register and coincidence circuit via a first amplifier having four divided outputs, two of which are connected to respective inputs of the ring shift register, whereas the remaining two are connected to the inputs of the coincidence circuit.

Abstract: A system incorporating a photosensitive device and associated circuitry for scanning a line to be traced.

Abstract: A machine for repetitive cutting of small identical parts from a relatively large metal plate. A scanning head is positioned on a carriage above a template which is mounted to a tracing table, and one or more metal cutting heads are also mounted on the carriage. The scanning head is operable to drive the carriage and cutting head to cut a first series of one or more identically shaped parts from the plate. A further carriage on the machine is movable between a stop and an adjustable limit switch, with the adjusted distance between the stop and switch corresponding to the pre-determined distance it is desired to shift the tracing table to position the template for controlling the cutting of a second series of one or more identical parts from the same plate. The further carriage is selectively connected to a table moving mechanism, and such connection also actuates the latter to move the table until the carriage engages the limit switch.

Abstract: The phototracing system for controlling the motion of the work-performing member of a two-coordinate copying machine for pattern-cutting of sheet materials, wherein the tracing photo-head cooperates with a template drawing wherein the line being traced is represented as a "black" to "white" transition, by means of an optical scanning beam. The aperture of the optical beam in the plane of the template drawing has finite dimensions and is driven through a circular scanning motion at a permanent angular speed about the optical line of the tracing head.The phototracing system includes a train head with a photoelectric transducer connected with two shapers of short pulses of the signal of the prefixed instantaneous change from "white" to "black" and from "black" to "white", respectively. The output of the second shaper of the short pulse of the prefixed instantaneous change from "black" to "white" has connected thereto means for delaying each pulse.

Abstract: A curve tracer comprising: an optical tracer head for scanning a line having at least a substantial transverse component and at least one marking on the line, with a predetermined scanning speed. The head is moved along the line at a speed substantially lower than the scanning speed. There is a control unit for controlling the movement including an integrator, means for feeding the integrator with a voltage proportional to the speed of the tracer head, and means for supplying a signal proportional to the distance travelled by the tracer head when the head moves over the marking.

Abstract: An apparatus capable of digitizing or plotting coordinate locations and lines utilizes an automatically controlled carriage that is translated over the supporting surface of a digitizing and plotting table and a free cursor for identifying specific coordinate locations on the table. Radiation means, such as electromagnetic coils, are mounted on the carriage and the cursor to produce signals indicative of the relative positioning of the carriage and cursor during a digitizing mode of operation. The position signals are transmitted to controlled drive motors which cause the carriage to follow the cursor over the supporting surface. Encoders, also operated by the drive motors, allow the position of the carriage and, hence, the cursor to be recorded for subsequent usage. A plotting instrument such as a pen is mounted on the carriage so that the apparatus can be used in a plotting mode of operation to generate graphic information.

Abstract: A vehicle guidance mechanism for guiding a vehicle along a guide line comprises a radiation source that causes the guide line to reflect or emit a guidance signal; photocell sensors mounted in the vehicle and adapted to sense the guidance signal and produce an error output signal proportional to the variation of vehicle position from a predetermined lateral position with respect to the guide line; and a control device in the vehicle adapted to steer the vehicle in response to the error signal so as to cause the vehicle to follow the guide line. An automatic contrast or gain control circuit eliminates the effect of background illumination in the output signal received from the guide line. Modulation circuitry and appropriate filters reduce the effects of static background illumination and improve the reliability and line detecting ability of the guide system. Line detection circuitry is employed to prevent operation of the automatic control device unless the vehicle is tracking a valid guide line.

Abstract: A system incorporating a photosensitive device and associated circuitry for scanning a line to be traced.