Abstract: A numerical control device for a machine tool switching two reference axes comprising switching timing determining means for determining a timing for switching the moving position definition on the basis of the first reference axis and the moving position definition on the basis of the second reference axis; and reference axis switching means for switching, in response to the switching timing determining means, the moving position definition on the basis of the first reference axis and the moving position definition on the basis of the second reference axis.

Abstract: A method, system, and computer program product for non-real-time trajectory planning and real-time trajectory execution. A trajectory planning process receives data generated by high-level control software. This data defines positions and scan velocities, where multiple axis motion must be precisely synchronized. The trajectory planning process creates sequences of constant acceleration intervals that allow critical motions to be executed at maximum throughput. The output of a trajectory planning process is known as a profile. A profile executor, using the profile output by the trajectory planner process, generates continuous, synchronized, filtered, multi-axis position and acceleration commands (i.e., execution data) that drive control servos. Time intervals generated by the trajectory planner are quantized to be integer multiples of a real time clock period.

Abstract: This invention relates to a control apparatus for numerical control in a cutting machine having a turret which can be rotated to arbitrary positions, and characterized by including means for obtaining turret axis data (?X, ?Z) from reference offset values (X0, Z0) corresponding to a length from a cutting edge to a turret axis B, turret angle data ?, and cutting edge data (m, n), and moving the turret on the basis of these turret axis data (?X, ?Z) to perform a cutting.

Abstract: Inductive position detector (10) is described which includes scale (20) having a longitudinal axis containing a train of magnetic balls (22), and a transducer (30) moveable relative to the scale (20). The transducer (30) includes means to induce a magnetic field in the scale (20). Magnetic markers (23) are provided at axially spaced locations along the scale (20). As the transducer (30) is moved along the scale (20), the pattern of magnetic markers (23) detected enables the position of the transducer to be determined.

Abstract: There is provided a finite type rolling guide deviation correcting method and system capable of detecting the deviation in relative position between a rolling guide and a movable body if the deviation in relative position increases, and automatically carrying out a correcting operation for returning the deviation in relative position to a normal positional relationship. The finite type rolling guide deviation correcting method corrects a relative positional relationship between a finite type rolling guide for guiding a reciprocating motion of a movable body and the movable body.

Abstract: In a machine tool with a spindle capable of motion along at least three axes x, y, and z, the position of the spindle is checked by a device that operates utilizing electromagnetic signals sent out by four emitters, located externally of the machine tool, and picked up by a receiver mounted directly to the spindle. The signals are fed into a master control unit and processed by circuits in such a way as to produce an output that can be used to verify and if necessary correct the position of the spindle on the three axes X, Y, and Z.

Abstract: The invention relates to a control method and a control device for the operation of rotationally or linearly driven axes with a position control. This involves determining the difference between the setpoint position value (LS) and actual position value (WI) caused by an additional movement component during the time period of the occurrence of at least one superposed movement by subtraction of one value from the other. Furthermore, it is possible to eliminate movement components which are known, periodic and can be mathematically determined as desired from all the required control data paths during the time period of the superposed movement.

Abstract: A spline interpolation motion control system and method that can automatically determine where sharp corners and flat sections were intended in a part program. In one embodiment, based upon the length ratio of two consecutive spans, the system and method determines whether to interpolate the first span with a line or with a spline function. If a parameter range is not met, then the span is interpolated as a line to maintain the intended flat section in the program. Also, in this embodiment, the angle defined by a pair of consecutive spans is used to determine whether the two spans should be interpolated with lines or with splines. If a tolerance is exceeded, then the spans are interpolated linearly to maintain the intended sharp corner in the part program.

Abstract: A position is obtained from a command movement for a controlled axis. The position of a virtual axis with respect to time and an I/O signal are obtained. The position of the controlled axis and the state of the I/O signal are stored in association with the position of the virtual axis, and cam shape data and I/O signal state data are obtained. During an electronic cam operation, the virtual axis position is controlled by means of virtual axis control means. Corresponding to the position of the virtual axis, the position of the controlled axis or the I/O signal state is read from the cam shape data and the I/O signal state data and outputted, whereby the controlled axis is driven.

Abstract: An apparatus for automatically controlling the work flow of a machine—equipped with effectors (2) driven by rotational motors (12)—comprises: electronic storage means (11) having resident functions that relate the angle of rotation described by a controlling motor (12) with the desired instantaneous position of a controlled effector (2); means (13) for detecting the actual instantaneous position of the controlled effector (2); comparator means (14) for determining the positional error of the controlled effector (2) relative to a given expected position upon reaching a certain angle of rotation of the controlling motor (12); and means (15a) for controlling the motor (12) of the controlled effector (2), which receive the error signal from the comparator means (14) and apply to the motor (12) a corresponding corrective action designed to control and synchronize the angular position of the controlled motor (12) with that of the controlling motor (12).

Abstract: An apparatus for automatically controlling the work flow of a machine—equipped with effectors (2) driven by rotational motors (12)—comprises: electronic storage means (11) having resident functions that relate the angle of rotation described by a controlling motor (12) with the desired instantaneous position of a controlled effector (2); means (13) for detecting the actual instantaneous position of the controlled effector (2); comparator means (14) for determining the positional error of the controlled effector (2) relative to a given expected position upon reaching a certain angle of rotation of the controlling motor (12); and means (15a) for controlling the motor (12) of the controlled effector (2), which receive the error signal from the comparator means (14) and apply to the motor (12) a corresponding corrective action designed to control and synchronize the angular position of the controlled motor (12) with that of the controlling motor (12).

Abstract: An arrangement for generating command variables for control loops of a numerically controlled machine that includes an interpolator unit for providing position set points with a defined interpolator scanning rate and a precision interpolator unit. The precision interpolator unit includes a scanning rate converter and a downstream-connected low-pass filter, wherein the precision interpolator unit is arranged downstream of the interpolator unit, which generates command variables at an output side from position set points at an input side for one or several downstream-connected control loops, wherein the precision interpolator unit generates command variables in a time pattern of the control loops with a control loop scanning rate.

Abstract: An indirect axis address command, “AX[controlled-axis number]=commanded movement amount”, which can designate a controlled axis to be commanded through a controlled axis number is used. The controlled axes number can be stored in a variable by “variable #100=AXNUM [axis address]”, for example. In this way, it is possible to cause different axes to carry out the same operations by the same program by changing the axis addresses stored in the variables. Because the controlled axis is designated by using the controlled axis number, operation can be performed.

Abstract: A lithography system and method for calculating an optimal discrete time trajectory for a movable device is described. A trajectory planner of the lithography system calculates an optimal discrete time trajectory subject to maximum velocity and maximum acceleration constraints. The trajectory planner begins by calculating a continuous time, three-segment trajectory for a reticle stage, a wafer stage or a framing blade, including a first phase for acceleration at the maximum acceleration to the maximum velocity, a second phase for travel at the maximum velocity and a third phase for deceleration at the negative maximum acceleration to a final velocity. Next, the trajectory planner converts continuous time, three-segment trajectory to a discrete time trajectory. The time of execution of the resulting trajectory is at most three quanta greater than the time of execution of the continuous time trajectory. One advantage of the system is the reduction of scanning times of a lithography system.

Abstract: A method and system for providing control that include providing a workpiece that includes a target shape, providing a cutting tool, providing a 3-D image associated with the workpiece, identifying the target shape within the workpiece image, providing a 3-D image associated with the cutting tool, registering the workpiece with the workpiece image, registering the cutting tool with the cutting tool image, tracking at least one of the workpiece and the cutting tool, transforming the tracking data based on image coordinates to determine a relationship between the workpiece and the cutting tool, and, based on the relationship, providing a control to the cutting tool. In one embodiment, the workpiece image can be represented as volume pixels (voxels) that can be classified and/or reclassified based on target shape, waste, and/or workpiece.

Abstract: A method and system compensates for vertical deflection for parts manufactured by a numerically controlled (NC) machine. The (NC) machine has an application head position programmed to a plurality of nominal tool coordinates. Each nominal tool coordinate has a horizontal coordinate, a rotational coordinate, and a vertical coordinate. A tool used to manufacture the part is placed on the NC machine. The tool has a plurality of actual tool coordinates, each actual tool coordinate has a horizontal component, a rotational component, and a vertical sag component. A difference between each vertical sag component and a corresponding one of the nominal tool coordinates is calculated. Each difference is multiplied by a multiplier value providing an adjusted sag value. Each adjusted sag value is subtracted from the application head position for each actual tool horizontal or rotational coordinate to compensate the part for the vertical sag of the tool during manufacture.

Abstract: A positional control system wherein the position of the controlled object connected to a drive is controlled to a variable target or desired position. A period is determined which starts with a detection of a reversal in the direction of the feed of a positional command Pr as well as the detection of a stoppage of a table 104 as a controlled object and which ends with a detection of the re-start of the movement of the table 104. During the period, a correction amount for correcting a positional deviation E is issued.

Abstract: A system and method for estimating the position of an object in three dimensions uses two cameras interconnected with a machine vision search tool. The search tool is capable of registering transformation of a pattern in at least two translational degrees of freedom, along the image plane, and at least one non-translational degree of freedom along a camera axis perpendicular to the image plane. The tool can be a rotation/scale-invariant (RSIS) search tool. A nominal position for each camera's acquired image of the object is determined and a set of uncertainty vectors along each of the degrees of freedom is generated. The vectors are weighted, with the respective vectors along the camera axis being weighted more-highly than orthonormal vectors within the image plane. The weighted vectors are combined to define an error.

Abstract: A profile data compensating method comprises a step of generating effective profile data by operating a machine tool under a non-load condition in accordance with theoretical profile data, a step of generating first error profile data representing error components of a control system, a step of generating first compensated profile data based upon the first error profile data, a step of generating measured profile data by measuring the shape of the workpiece machined in accordance with the first compensated profile data, a step of generating second error profile data representing error components of a mechanical system, and a step of generating second compensated profile data based upon the first and second error profile data.

Abstract: The machine controlled by the device comprises a set of cutting tools interchangeable in dependence on the blank to be cut, means adjustable in dependence on the jobs to be performed by each tool, and means for actuating the adjustable means. The control device comprises a memory (1) associated with each cutting tool in order to store the data relating to the characteristics of the tool and of the operations for adjusting the machine (5) in order to use the tool, reading means (2) for reading the data in the said memory, means (3) for displaying a menu relating to the data and control means (4) for generating and transmitting control signals (6, 7, 8) to the actuating means in dependence on the menu.

Abstract: An automated computer-implemented method for generating commands for controlling a computer numerical control machine to fabricate an object from a workpiece. The method includes the steps of: (1) determining a first set of Z coordinates for machining a first set of Z level planar slices with a first tool; and (2) determining a second set of Z coordinates for machining a second set of Z level planar slices with the first tool. The second set of Z coordinates is partitioned into one or more subsets. Each subset corresponds to a pair of adjacent Z coordinates belonging to the first set of Z coordinates. A distance between the Z coordinates of each subset is a unit fraction of a distance between the Z coordinates of the pair of adjacent Z coordinates which corresponds to each subset.

Abstract: The invention includes: a numerical controller for controlling a servo amplifier in accordance with a given motion command; a memory for storing as variables motion command data such as speeds and positions; a motion API which is called by an application program on a personal computer and which gives a motion command via a bus such as a PCI bus to the numerical controller; and means for indirectly specifying the address of a variable of motion command data present in the memory by way of the motion API.

Abstract: A method of recording aligned images on two sides of a printed circuit board substrate, including: recording an image of an electrical circuit pattern on a first side of a printed circuit board substrate; forming an alignment pattern on a side of the printed circuit board substrate, wherein the alignment pattern has a known spatial relationship to said image of an electrical circuit pattern; determining a location of the alignment pattern on the printed circuit board substrate; and recording an image of an electrical circuit pattern on a second side of the printed circuit board substrate in response to the determined location of the alignment pattern.

Abstract: A method for creating and/or optimizing a cam-disk function for a controller for controlling a moving machine element of a numerically controlled production machine during its operating time system, movement of the machine element being described in sections by the cam-disk function, comprising defining individual movement sections by segments and/or points, and interpolating between said movement sections in accordance with prescribable interpolation rules; wherein instructions for inserting said segments and points and for prescribing said interpolating rules are provided at the point in time during the operating time of the system of the machine controller.

Abstract: A lost motion correction value setting method for a machine tool of a hybrid control system that performs a positional loop control with both machine position signals outputted from position detecting scales for detecting machine positions and motor position signals outputted from rotary encoders for detecting a rotational angle of a feed driving servomotor includes executing a test program; periodically inputting the machine position signals outputted from the position detecting scale and the motor position signals outputted from the rotary encoder; determining errors by determining the difference between the machine position signals and the motor position signals, determining the difference between an average value on an advance side and an average value on a return side of the errors, and storing the difference in lost motion correction value memories as a dynamic lost motion correction value.

Abstract: A method for processing one or more manufactured parts is provided. The method includes generating a number of tool paths corresponding to a feature to be added to the one or more manufactured parts. Each of the tool paths has an effect on a respective one of the representative manufactured parts. The method further includes clustering the tool paths into a number of clusters based on the respective effect and a tolerance of the feature being added to the representative manufactured part and processing a manufactured part using one of the tool paths, which corresponds to a respective subpopulation in which the manufactured part lies.

Abstract: A method for controlling a mechanism through the use of higher-dimensional n-curves is disclosed. An electronically-controlled mechanism is provided. Electronic communication is established between a computer and the electronically-controlled mechanism. A controller is running or executing on the computer to send mechanism commands to the electronically-controlled mechanism. Process control software is used to control the electronically-controlled mechanism. The process control software uses higher-dimensional n-curves to control the electronically-controlled mechanism.

Abstract: A method for defining a numerically controlled (NC) tool path on a identified region of a solid computer model is disclosed. In an exemplary embodiment, the method includes identifying boundary points so as to bound the identified region. The boundary points are processed so as to generate a plurality of bounding curves, wherein the bounding curves are generated so as to conform to a surface of the identified region. The NC tool path is then generated in a manner conforming to the bounding curves.

Abstract: Slitting knife arrangement in a slitter is controlled by a controller by use of a fixed common program without changing the program when a new setting of slitting knife arrangement is specified. To derive a series of signals to move slitting knives in the slitter, the controller requires input of a next slitting width and the number of slitting knives to be used next. In addition to the two input parameters, additional parameters of current positions of the slitting knives and the number of slitting knives currently used can be acquired from memory in the controller for deriving the series of signals.

Abstract: In detecting a boundary line between areas different in light reflectance, it has so far been impossible to specify the boundary line at a distance shorter than the arrangement pitch of photodetectors (pixels) arranged in the camera. In the present invention, luminance variations near the boundary line between areas different in light reflectance are derivated. Further, in unit blocks G corresponding to pixels and arranged in a direction (Y direction) in which the boundary line extends, derivated values of luminance for each row of unit blocks are added and then a variation curve of the added values of derivated luminance values in unit block rows is drawn to specify a peak position thereof and also specify the position of the boundary line X0. Thus, it is possible to specify the position of the boundary line with a high accuracy at a distance shorter than the unit block pitch.

Abstract: The position of the inner surface of a hollow metal workpiece on a machine tool is detected by connecting an operating member of the machine, preferably a tool, to a first terminal of an electric power source; connecting the inner surface to a second terminal of the power source; moving the operating member gradually towards the inner surface to detect the emission of a signal generated by an emitting device interposed between one of the terminals and the inner surface, and corresponding to a condition in which initial contact is established between the operating member and the inner surface; and determining the position of the operating member at the instant the signal is emitted.

Abstract: A numerical control device for a machine tool switching two reference axes comprising switching timing determining means for determining a timing for switching the moving position definition on the basis of the first reference axis and the moving position definition on the basis of the second reference axis; and reference axis switching means for switching, in response to the switching timing determining means, the moving position definition on the basis of the first reference axis and the moving position definition on the basis of the second reference axis.

Abstract: A machining program is read in and interpreted and a determination is made as to whether the amount of movement called for by a block of commands is larger or smaller than a minimum amount of movement that is established by a feed speed and a one sampling period of a numerical control apparatus. If the amount of movement called for is greater than the minimum amount of movement, feed control is performed in accordance with the current block. If the amount of movement called for by the current block of commands is smaller than the minimum movement amount, an immediate subsequent block of commands is concatenated with the current block, and this concatenation of command blocks is continued until a synthesized block calling for an amount of movement greater than the minimum amount of movement is obtained, this synthesized block then being used to perform feed control.

Abstract: A numerical control apparatus of a machine tool capable of shortening a machining time while maintaining a machining precision of a workpiece, provided with an analyzer for analyzing a machining program defining machining process of a workpiece by the machine tool to extract information for specifying a feed speed of a cutting tool to the workpiece and cutting/non-cutting information for defining actual cutting by the cutting tool added to a cutting feed command program from the cutting feed command program contained in this machining program, a feed speed optimizer for calculating a permissible feed speed of the cutting tool in accordance with content of the cutting/non-cutting information based on the extracted information and optimizing the feed speed of the cutting tool so as to be within the permissible feed speed, and a distribution unit for calculating control commands to be distributed to the control axes of the machine tool based on the optimized feed speed.

Abstract: The invention relates to a method of displaying a shape of a material and a shape of a product for a speedy machining simulation. In the machining simulation wherein the shape of the material, the shape of the product, and a shape of a tool are displayed as images on a display unit, and portions of the image of the material and the image of the product overlapping the image of the tool are successively eliminated, the shape of the product in accordance with a portion to be machined is displayed as a line image indicating only an outline of the product, on the other hand, the shape of the material is displayed as a plane image indicating an area in correspondence with a machining allowance, in case that the material includes the portion to be machined which is formed by adding the specified machining allowance to the outline of the product. Therefore, a data input in relation to the shape of the material can be simplified, whereby the speedy machining simulation is enabled.

Abstract: A method of making a tool path, wherein a shape to which an object surface is to be processed and processing conditions are inputted, and a processing region is designated on the processing region, and a tool path on the processing region is calculated on the basis of the reference lines. When the number of the processing region is one, a tool escaping expansion region is added to a terminal end in the picking direction of the processing region, or a tool approaching expansion region is added to a starting end in the picking direction of the processing region. When the number of the processing regions is not smaller than two, a tool escaping expansion region is added to a final end in the picking direction of the processing region precedingly, and a tool approaching expansion region to a starting end in the picking direction of the processing region posteriorly.

Abstract: SmartPath provides CNC machinists using CNC Controllers a database of cutting methods, which will be automatically applied when the CNC Controller anticipates the upcoming scenario. SmartPath acts as a database collecting information about the machine's stresses and the machine's ability to cut a part. The CNC Controller in real time gathers this information as the machine moves and then automatically adds the information to the database. SmartPath is a form of artificial intelligent learning gathering its knowledge from the feedback of the CNC machine controller as it cuts. The operator can insert and override any of the cutting methods or scenarios.

Abstract: A controlling apparatus for a robot of the type formed by a plurality of joint actuators and operating in accordance with a behavioral schedule comprises a behavior scheduling unit for setting a robot's behavioral schedule, an operation controller for implementing an operational pattern corresponding to the behavioral schedule as determined by the behavior scheduling unit by driving each joint actuator, a detector for detecting the state of operation implementation by the operation controller and a recording unit for recording a log including the behavioral schedule by the behavior scheduling unit and the state of operation implementation by the detector. A user issuing a command for the robot is authenticated and the contents of the command supplied from the user are recorded in combination with the behavior taken by the robot responsive to the command and the time point of implementation of the behavior.

Abstract: Functions in various kinds of forms, whether to be rational functions or not, to express a plurality of curved surfaces are unified into a set of functions with respect to parameters u and v by an algebraic method or an analytical method. Based on the set of functions, intersections which are necessary for machining of the curved surfaces are calculated, and paths of a cutting tool to machine the curved surfaces are determined.

Abstract: A lithography system and method for calculating an optimal discrete time trajectory for a movable device is described. A trajectory planner of the lithography system calculates an optimal discrete time trajectory subject to maximum velocity and maximum acceleration constraints. The trajectory planner begins by calculating a continuous time, three-segment trajectory for a reticle stage, a wafer stage or a framing blade, including a first phase for acceleration at the maximum acceleration to the maximum velocity, a second phase for travel at the maximum velocity and a third phase for deceleration at the negative maximum acceleration to a final velocity. Next, the trajectory planner converts said continuous time, three-segment trajectory to a discrete time trajectory. The time of execution of the resulting trajectory is at most three quanta greater than the time of execution of the continuous time trajectory. One advantage of the system is the reduction of scanning times of a lithography system.

Abstract: A semiconductor circuit that includes components and registration features that are electrically isolated from the components. The registration features form projecting parts that are uniformly distributed in the form of a matrix over at least part of the external surface of the circuit so as to define adjacent registration areas. In a preferred embodiment, the semiconductor circuit also includes metal registration features that are produced in at least one metallization level of the circuit. Also provided is a method of adjusting a tool so as to put it into a particular position with respect to the surface of a semiconductor circuit that has registration features defining adjacent registration areas. According to the method, an at least partial topographic record of the registration features on the surface of the semiconductor circuit is produced, and the registration features of the topographic record are brought into coincidence with reference features of a reference drawing.

Abstract: A robot alignment system (10) includes a sensor system (12). The sensor system (12) is designed to attach to an end effector of a robot arm (14). A rough alignment target (16) is attached to a work station. A fine alignment target (22) is placed on a work surface of the work station. The sensor system (12) first determines the rough alignment target (16). The robot arm (14) is then moved to detect the fine alignment target (22).

Abstract: By implementing a sequence control in a numerical control, tool-related machining operations and position elements are executed depending on the technology-dependent sequence in the machining program so that all cycles of a machining operation are selected consecutively as modal cycles, with all cycles being selected consecutively for a position element for each cycle for a machining operation, and the respective operation being executed at the position of the respective position element prior to the following cycle being selected as a modal cycle for an operation. Thus unnecessary tool changes are avoided and therefore machining productivity is increased.

Abstract: An automated computer-implemented method for generating commands for controlling a computer numerical control machine to fabricate an object from a workpiece. The method includes the steps of: (1) determining a first set of Z coordinates for machining a first set of Z level planar slices with a first tool; and (2) determining a second set of Z coordinates for machining a second set of Z level planar slices with the first tool. The second set of Z coordinates is partitioned into one or more subsets. Each subset corresponds to a pair of adjacent Z coordinates belonging to the first set of Z coordinates. A distance between the Z coordinates of each subset is a unit fraction of a distance between the Z coordinates of the pair of adjacent Z coordinates which corresponds to each subset.

Abstract: The chuck 10, for positioning and holding a pipe at any rotational angle position around the axial center, is provided with the three dimensional linear processing machine. When the machining program PRO is composed, a plurality of the shape patterns KPT classified machining modes concerning pipes by machining shape is displayed on the display 23. Furthermore, dimensional data item concerning selected shape pattern is displayed on the display 23. Then, the machining program PRO is composed on the basis of the input code parameter CP and the selected shape pattern KPT. Besides, shift quantity TMz and TMy are measured when the pipe to be machined is installed on the chuck 10, and on the basis of this, the machining program PRO is amended and executed.

Abstract: The present invention relates to a data generating device, a data generating method and a data generating program for generating numerical data for controlling the operation of a cutting tool when machining an article.

Abstract: In the movable shaft (32) constructed by a plurality of motion modules (31), since the moving command based on the machining program (1) in unit of the movable shaft like the prior art is converted into moving commands of the motion modules (31) to control this movable shaft (32), the machining can be executed if the machining for the movement of the movable shaft is defined like the machining program in the prior art. Also, assignment of a plurality of motion modules (31) to the movable shaft (32) can be set arbitrarily and then the pulse distribution to the movable shaft (32) is executed in response to this assignment. In addition, if the failure is caused in the motion module (31), such motion module (31) can be disconnected.

Abstract: Disclosed is a system and method for processing crank angle signals. The system comprises a crank angle sensor for converting a rotation of a crankshaft into analog signals; a switching circuit for converting the analog signals into crank angle signals; a timer/counter for detecting a number of pulses and tooth periods of the crank angle signals; a phase sensor for converting a rotation of a camshaft into cylinder identity signals and outputting the cylinder identity signals; and an electronic control unit for receiving the crank angle signals and the cylinder identity signals and using the signals to determine cylinder identity and rpm.

Abstract: A method of making a tool path, capable of making a difference in level of a part of a surface being processed inconspicuous, and obtaining a smooth processed surface. According to this method, a shape to which an object surface is to be processed and processing conditions are inputted, and a processing region is designated on the surface to be processed. Reference lines are designated on the processing region, and a tool path on the processing region is calculated on the basis of the reference lines. When the number of the processing region is one, a tool escaping expansion region is added to a terminal end in the picking direction of the processing region, or a tool approaching expansion region is added to a starting end in the picking direction of the processing region.

Abstract: A position detector detects the position of a detector section relative to a record medium having recorded thereon a periodic position signal. The detector section has two detectors that produce first and second detection signals that are polar converted and processed, based on the number of divisions in a quadrant of the periodic position signal.