Abstract: Electronic components such as chips are attracted to the tip ends of nozzles under suction, and mounted on printed-circuit boards when the vacuum condition in the nozzles is broken. The time for breaking the vacuum condition in the nozzles is adjusted by a variable time adjusting unit based on angular displacement information of a cam which vertically moves the nozzles depending on the selected mounting cycle. Even when a different mounting cycle is selected, time delays are varied to adjust the time for breaking the vacuum condition in the nozzles for thereby-mounting electronic components accurately and stably on printed-circuit boards.

Abstract: A motor control system and the electrical bus for interconnecting the components of the control system are disclosed herein. The system includes a main motor control unit connected to four motor axis control modules. The control algorithms and commands for the system are stored and executed by the control unit which communicates control commands to the individual motor axis control modules. Each motor control module processes the control commands to control a motor connected to the module, and also communicates feedback signals produced at the associated axis to the control unit. The interconnection between the control unit and the modules is positioned at the face of the components to facilitate removal and insertion of the modules. The electrical bus includes both communications conductors and power conductors, and is included in the interconnection of the components.

Abstract: The present invention is a method and apparatus for defining the critical characteristics of a pallet, or tray, used to supply workpieces to an automated, flexible assembly station or workcell. Once the characteristics are described and stored in memory, they may be used to uniquely identify workpieces which are determined to be defective during the automatic assembly operations.

Abstract: The disclosed method involves teaching a robot by moving a robot member and sampling its position at predetermined times. Only position data changed more than a predetermined difference from the last stored position data are recorded as instruction data and the instruction data are played back as position data at predetermined times independent of the time required to move the robot member in the teaching steps.

Abstract: The present invention is suitable for examination of the rotating state of a Polygonal mirror motor in an image forming apparatus. It is judged whether or not the rotational speed of the motor is a target speed until a first time period has elapsed since the supply of power to the motor for rotating a Polygonal mirror was started every other second time period sufficiently shorter than the first time period and continuously checked over a third time period which is sufficiently shorter than the second time period. If it is judged that the rotational speed of the motor is the target speed continuously for the third time period, it is judged again whether or not the rotational speed of the motor is the target speed after an elapse of a fourth time period since the judgment. If the rotational speed of the motor is the target speed, the motor outputs a signal indicating that the motor is stabilized at the target speed.

Abstract: A duty factor of a pulse is set in accordance with duty factor data at each timing determined by a timer function to change the duty factor of the pulse in one step of the drive of a stepping motor in order to control the motor power in open loop.

Abstract: A numerical controller for an industrial machine such as a robot and an assembling system utilizing plural robots. The numerical controller controls movements of plural movable portions of the industrial machine by a synchronous control in which plural movable portions are moved in a synchronized manner. Based on an operational program, the numerical controller identifies a movable portion or movable portions which must be moved independently from other movable portion. The identified movable portion or portions are moved by an independent control. On the other hand, movable portions which are not designated are moved by synchronous control. Further, plural groups of movable portions may be formed for the synchronous control. In this case, movable portions in each group are controlled in a synchronized manner independently from other groups.

Abstract: A drive control and interface apparatus housed within an advertising display for driving a stepper motor coupled to a display device to sequentially display a plurality of images. The drive control and interface apparatus includes a microprocessor having program memory connected to the motor through a motor driver. A drive control program operates the microprocessor to drive the stepper motor to change the image displayed after a corresponding predetermined period of time. The program includes drive routines for fast and slow image changes that drive the stepper motor to minimize resonance. A control interface connects to the microprocessor. The program is responsive to the control interface to permit manual sequencing of the display and user selection of the corresponding display times for each image.

Abstract: A motorized mount for a laparoscopic camera, with the mount being remotely controlled based upon movements of the user's head. The camera mount is connected to the operating table and to the laparoscopic camera. Control means may cause motion of the mount to pan horizontally, tilt vertically, and zoom the camera. The control means receives input signals from a tracking device which determines the three-dimensional position of a special headset mounted on the user. A foot pedal is operatively connected to the control means. In a first setting of the foot pedal the user may move freely without causing camera movement. Upon moving the foot pedal to the second condition, the control means sets the position of the user's head as a null position. Thereafter, pivotal movement of the head to the left, right, up, or down, or translational movement of the head forward or rear, will result in similar movements of the camera.

Abstract: A robot for guiding movements has its power provided by an operator who handles a tool integral with the robot. Like a conventional robot, the guiding robot has several axes respectively associated with rotation sensors that are connected to a computer system memorizing a path to be followed. When the operator moves the tool beyond the stored path, blocking devices, controlled by the computer system and replacing the robot's motors, prevent the tool from continuing to depart from the path. Thus, at any time, the operator can move the tool within the stored path only. The blocking devices are passive, that is, they are such that they can only resist to a movement but cannot generate a movement, which prevents the occurrence of any uncontrolled movement.

Abstract: A numerical control system for controlling a machine tool including a control device for controlling the machine tool; external portable storage device for storing data; a disabling device for disabling the control device; a read/write device, operable when the external portable storage device is manually coupled thereto, for reading data from the external portable storage device and for writing data to the external portable storage device; and a determining device for determining whether the external portable storage device is coupled to the read/write device.

Abstract: In an numerical control machining system, a plurality of parts on a work are cut into predetermined shapes with one cutting tool by moving back and forth the cutting tool a plurality of times for each part to be cut. When determining a tool running path, a cutting trajectory of the cutting tool for each of the parts is obtained, all the end points of the cutting trajectory which can be a tool inlet end or a tool outlet end for each of the parts are stored, the part the cutting trajectory for which has an end point which is the nearest to the tool outlet end of the cutting trajectory for one of the parts as measured along the path of movement of the tool is determined to be the part to be cut next, and said nearest end point is determined to be the tool inlet end of the cutting trajectory for the part to be cut next.

Abstract: The present invention includes a crucible which holds volatile material to be tested. The crucible is lowered into an oven apparatus and removed from the oven apparatus by equipment programmed in a predetermined manner.

Abstract: In a servo system using a discrete signal relative to a position, a time delay and an error upon detecting a speed due to lack of positional information are eliminated to achieve a positioning to a target position in a short time. A pulse signal X.sub.P relative to a position is used to establish synchronization with an observer which is adjusted to match with an actual apparatus comprising a load, a motor and so on, and an estimated speed value or an estimated position value generated by the observer are used to determine an operating signal for the servo system.

Abstract: A motor controller is programmed for detecting motor-stall condition of a dc motor under the control of a motor control system. The motor control system includes a programmable microcontroller in connection with the motor controller and a motor driver. The motor driver communicates with a dc motor. The dc motor is coupled to a position encoder which encoder is in communication with the microcontroller. The method comprises the steps of providing an average stall threshold value ASV and providing the motor controller with a time counter for counting each time interval T to a maximum count N. The motor controller is programmed to issue a motor command representing the position error between the desired motor position and the actual motor position for some time interval T. During each time interval T, the motor command is compared to the average threshold value ASV, if the motor command is greater than the ASV then the count in the time counter is compared with the maximum count N.

Abstract: A numerical control system controls a plurality of axes with a plurality of channels (10.about.40). A plurality of spindles (61.about.64) or automatic tool changer controllers (51, 52) are selected and controlled by the channels (10.about.40) according to machining programs. The numerical control system efficiently controls a machine tool having a number of spindles and automatic tool changer controllers.

Abstract: A coordinate data converter converts plural shape data of the movable parts from a direction and of the parts that may interfere with the movable parts into the shape data of the three-dimensional coordinate system unique to the machining system, the number of structural shape elements of those parts being different from one another. A generator projects thus converted shape data on the three planes of said three-dimensional coordinate system; an arithmetic operator determines whether or not projected data overlap each other in each of the three planes, and a detector determines that an interference has occurred if the projection data on respective planes overlap and if projected data based on the shape data overlap in all of the three planes.

Abstract: A method and device of achieving motion cycle time reduction that takes motor capabilities, load inertia and gravity into account and, at the same time, produces acceptable tool tip vibration upon stopping. This cycle time reduction is especially applicable to short motions of a robot where the entire motion consists of acceleration and deceleration and there is no constant velocity region. The method and device provide open loop limiting factors for axis jerk, acceleration and velocity, taking into account robot position, payload and inertia.

Abstract: The present invention relates to a method of generating data indicative of robot control axis position. The method has a step of inputting data specifying the shape of a workpiece (WK) and data (.alpha., .beta., .gamma.) specifying the attitude of a tool (TL) conforming to a task to be executed by a robot, a step of calculating a position (X, Y, Z) of a tip (P) of the tool in the workpiece coordinate system X-Y-Z by using the data specifying the workpiece shape, a step of specifying the position of each axis constituting the robot by using the tool tip position and the tool attitude data, and a step of successively specifying positions of each control axis of the robot along a tool path (PT).

Abstract: A system and method for controlling an amount of force supplied by a motor to move an object from an at-rest position is presented. The system comprises a motor controller configured to provide a motor control signal to control the amount of force supplied by the motor, and a position sensor configured to detect an actual position of the object being moved by the motor and to send an actual position signal to the motor controller. The motor control signal supplied by the motor controller controls the motor such that the motor supplies a cubic increase in force on the object to move the object from its at-rest position. The motor controller comprises a profile generator, configured to provide an acceleration profile, a velocity profile and a position profile, and to output a drive signal in response to the position profile, wherein the position profile represents a desired position of the object as a function of time. The position profile is a cubic profile as a function of time.

Abstract: The present invention allows easy restarting of a multiple product machining function in interrupted punch press work. An interrupted machining position is identified with a product number set on a work and a product number of a product for which machine operation is stopped or a product number of a product to be next machined is entered. When this product number is entered, a command program is modified according to a product number entered. The modified program gives machining commands from a work position for a product other than the product for which machine operation is interrupted to a punch press machine.

Abstract: The present invention provides a stroke operation mechanism which is incorporated in a single-structure press machine so that various types of stroke operations can easily be generated on the slide side, and a control method for controlling the stroke operation mechanism so as to cause the mechanism to exhibit various types of stroke operations. The press machine stroke operation mechanism has a driving system having a feed screw member disposed on a plane in parallel therewith, at least one pair of nut members screwed on the screw member and moved by rotation of the screw member so as to separate from and approach to each other, and a servomotor for supplying torques for normal and reverse rotations to the screw member; and a slide system having a slide member supported below the screw member at right angles therewith so as to be vertically slidable, and a transmission bar member having an upper end axially connected to the nut members and a lower end axially connected to the slide member.

Abstract: An electromagnetic sub-stage and an electromagnetic monolithic stage coupled such that one follows the other having a single reference surface positioned therebetween. A sub-stage having linear motors for movement in the X-Y direction is mounted by a U bracket to a monolithic stage. The monolithic stage is suspended by flat electromagnetic coils providing precise motion of the body of the monolithic stage in X, Y, Z, and rotation about the Z axis or .theta.. Follow control means links or tracks the movement of the monolithic stage to the sub-stage such that the monolithic stage positioning coils are centered in their respective magnetic structure. Adjustable mechanical stops attached the monolithic stage in combination with air bearings riding on the reference surface limit travel of the monolithic stage in the focus or Z direction. The single reference surface extends over the entire range of motion of the monolithic stage. This improves position accuracy, and cleaning and servicing of the apparatus.

Abstract: A positional control apparatus capable of readily moving a movable part of an NC device in any desired direction by using a particular handle. The handle is mounted on the movable part by a holding part. When an operator gripping the handle wishes to move the movable part in the desired direction, a strength and a direction of force given to the handle are detected by force sensors, and an axial moving amount calculation means calculates the moving amount of each control axis in consideration of the strength and the direction of the force given to the handle, detected by the force sensors as a strength and a direction of an acceleration given to the movable part. By the moving amount of each control axis, obtained by the axial moving amount calculation means, the positional control of the movable part is performed.

Abstract: An electric control for gas furnaces which controls a two speed main blower fan and an induction draft fan based on inputs from a room thermostat, a high limit and an ignition control including a gas valve. The control has a circuit board having a power supply for providing 24 volts DC current source to drive DC relays and a 5 volt DC power source to power a microprocessor. 24 volt AC input signals are coupled to the input ports of the microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. The output ports of the microprocessor are connected to a relay driver which in turn is connected to the relays. Several breakaway tabs in the board provide optional features such as eliminating a normally provided draft delay timing function. Test pads are provided on the board so that the board can be tested during manufacture.

Abstract: The present invention discloses a control device containing a device detecting a velocity or an acceleration parameter of the main robot body. The velocity or acceleration parameters are expressed in a robot coordinate system and is detected from the detection device. The output from the detection device is even added to a desired value that is expressed in an absolute coordinate system that is in an inertial reference frame for an arm of the robot. In this way, the robot arm can be made to follow any desired path, by using desired positions in the absolute coordinate system that is an inertial coordinate system.

Abstract: Method and device for controlling a motor in a powered seat, wherein a certain standard physique classification is set according to the height of an occupant on the seat, and on the basis of such physical classification, several predetermined standard positions are preset in a central processing unit, and wherein such standard positions may be selected and set temporarily by a mode selection switch and position switch for proper motor control, and further, a desired change of position may be made from the standard position by a manual switch.

Abstract: A numerical control system for controlling a plurality of axes with a plurality of functional arrangements includes a controller bus (1) having a plurality of slots, a plurality of controllers (10, 20, 30) each of which can read, decode, and execute numerical control commands for a group of axes. The controllers are connected to the channel bus (1), and axis control modules (3, 4) for controlling a plurality of servomotors. The controllers (10, 20, 30) share processing operations and use common peripherals, making the numerical control system flexible.

Abstract: In a method of storing teaching points of a robot, when teaching points for a plurality of moving units are input, information for identifying the moving units associated with the teaching points is input, and the teaching points and the identification data are stored in a single area of a memory.

Abstract: A printing cam is rotated forward from a print starting position by a motor in a printing operation. Then, a print hammer is driven in association with a cam follower driven by the printing cam, so that a printing operation is executed. An encoder disk is disposed so as to rotate integrally with the printing cam. A plurality of slits are disposed in an equidistantly spaced relationship in an encoder disk. A phase setting portion is provided in the encoder disk as a reference position for providing a rotational position of the encoder disk. The phase setting portion is an interval between two specific slits, the interval being formed by enlarging the interval between two slits. While the encoder disk rotates forward, a slit counter executes an additional operation every time a photosensor detects a slit. While the encoder disk rotates reversely, a slit counter executes an subtractional operation every time the photosensor detects a slit. After the printing operation is ended, the motor rotates reversely.

Abstract: A tool fastening apparatus for industrial robots comprises a coupling unit attached to the arm of a robot and a coupling unit attached to a tool to be used with the robot. When the two coupling units are joined together, their relative position can be easily and accurately fixed by means of positioning couplings comprising ball rings carrying a set of annularly arranged balls slightly sticking out from the plane of contact between the two coupling units. Accurate positioning is achieved by bringing the balls on the two ball rings into engagement, which, in turn, is achieved by fitting each ball on one ball ring into between two adjoining balls on the other ball ring.

Abstract: A method for controlling a lumbar support device and a motor control device provided, which are applied to a powered seat. The motor for causing fore-and-aft movement of a lumbar plate is controlled under a selected one of burst and fluctuation control modes. In the burst control mode, the lumbar plate is moved periodically in the fore-and-aft direction, whereas in the fluctuation control mode, the lumbar plate is moved in a aperiodic and weavering way in that direction, for example, on the basis of 1/f fluctuation waveform, to thereby alleviate a fatigue of lumbar part of a passenger sitting on the seat.

Abstract: A method of controlling the rotational speeds and phases of drum and capstan motors forming part of a servo system in a VCR by detecting signals that correspond to current rotational speeds and phases of the motors, and controlling the rotational speeds and phases of the motors by using the detected signals in rotational speed control and phase control routines. The speed control routine applys the steps of: inputting current rotational speed signals; producing rotational speed control signals corresponding to a rotational speed error signal; applying the produced rotational speed control signals to the drum and capstan motors to control their rotational speeds, performing a compensating operation necessary to the servo system, and then completing the rotational speed control routine.

Abstract: An improved servomotor control method where a multiplier ratio DMR is computed in advance by an arithmetic unit (20) from a traveling distance L of a movable machine element per revolution of a servomotor, a traveling distance R per pulse of a move command, and a number N of incremental pulses generated by an absolute position-detecting pulse coder (18) per revolution of the servomotor. A move command (.DELTA.R.sub.n) is accumulated by a move command accumulator (11), an absolute position (P.sub.A ') output by the absolute position-detecting pulse coder (18) is multiplied by the multiplier ratio DMR. A difference (E.sub.r) between a value (P.sub.c) obtained by accumulating the move commands and the result (P.sub.A) of the multiplication operation is computed as a position error, and rotation of the servomotor (17) is controlled by using the position error.

Abstract: A method and system for calibration of a primary signal processing path without interruption of signal processing utilizes a calibration signal processing path which is periodically used to process a signal concurrently with processing in the primary path. Any difference is compensated by gain adjustment in the primary path. In one form, a plurality of primary paths are sequentially compared with a calibrated path. The calibrated path is periodically checked using a precision reference and any error is corrected before comparison of the primary paths.

Abstract: The operation of positioning a machine by a numerical control apparatus is completed when it is determined that a current feedback value of a motor, which varies in response to deflection of the machine, is in a given range.

Abstract: A method of calibrating highly precise robots having a plurality of arms and axes comprises the method steps of: attaching an angular rate sensor (30) at an arm of the robot, adjusting the arm to a predetermined nominal position, generating an angular rate about an axis (40) of the robot, comparing the angular rate measured by the angular rate sensor (30) about its input axis (46, 48) with the nominal component of the angular rate generated about said axis (40), which nominal component results for the nominal position, and correcting the parameters of the robot according to the deviation of the measured angular rate and the nominal component.

Abstract: An actuator for a joint comprises a bladder-shaped chamber 5 whose one end is secured to an arm 2 by a mounting 6, whilst a bundle of fibres 7 extend from the other end of the chamber member 5 to a junction 8 on another arm 3. The rear wall 9 of the chamber member 5 is formed from woven bi-directional fibres 10 whilst the outer wall is defined by an array of high tensile fibres 11, at least some of which extend from the fibre bundle 7. The fibres 7, 10 and 11 are embedded in elastic material. When a pneumatic or hydraulic fluid is pumped through an inlet 12 to the chamber member 5, the latter expands and the fibres 11 bow outwardly, thus pulling on the fibres 7 and raising the arm 3, with the respect to the arm 2, to lift a weight 13.

Abstract: A collision detection/drive stoppage method capable of promptly detecting a collision of machine operating parts driven by servomotors with a foreign object, and of promptly stopping drive of the machine operating parts upon detection of a collision, thereby preventing or lessening damage to a machine, etc., caused by the collision. A digital signal processor of an axis controller, forming a software servo system, periodically calculates a velocity deviation (.epsilon.v) in accordance with a command velocity (Vc) calculated based on a command from a main computer and an actual motor velocity (V) from a pulse coder of the servomotor (S2), determines whether the absolute value (.vertline..epsilon.v-.epsilon.v'.vertline.

Abstract: Disclosed is an externally extended programmable controller in which a part of a control function is independently provided as an external unit, which comprises a main programmable machine controller (PMC) (2) contained in a numerically controlled apparatus (CNC) (1) and controlled in response to commands from the numerically controlled apparatus (1), an I/O unit (3) connected to the main PMC (2) for transmitting and receiving signals to and from a mechanical unit A (61), and an extended PMC connected to the main PMC unit through the I/O unit (3) for controlling a particular mechanical unit by an independent sequence program, and the extended PMC (4) independently contains a sequence program for a mechanical unit B (62) to be controlled, and controls the mechanical unit by transmitting and receiving commands and various data to and from the main PMC (2) by a communication means.

Abstract: A plurality of individual positions arranged on a surface area are toured. The individual positions are grouped such that each group occupies a continuous partial area in the positioning plane. The groups are ordered so that the partial areas adjoin each other, forming in their totality a geometrical coarse structure. The individual positions are continuously indexed such that their sequence follows the geometrical coarse structure. The indexing of the individual positions is altered in sections such that the time required for sequentially touring all the individual positions of a section is minimized.

Abstract: A technique of this invention discloses an orthogonal two-axis moving apparatus basically adapted to move in horizontal and vertical directions. In one embodiment the apparatus includes a vertical block, a horizontal moving member movably supported on the vertical block, and a driving mechanism for moving the horizontal moving member, a driving pulley, a driven pulley, and a belt for transmitting a driving force.

Abstract: A servo motor control device which performs suitable interpolation when given an external move command and for setting a target position on each coordinate axis is provided. The device comprises a revolution controller and a position detector for each axis of movement as well as a control gain controller. The revolution controller controls the number of revolutions of each of the servo motors involved using a control gain set individually for each coordinate axis and in accordance with a deviation between the current position of an object and a target position thereof. Based on control response delays which occur relative to each axis, the control gain controller changes a control gain individually set for each coordinate axis. In turn, the revolution controller controls the revolutions of each servo motor using the changed control gain. For any coordinate axis having no response delay, the control gain controller leaves a reference control gain unchanged.

Abstract: A method of controlling an articulated robot having in excess of six axes and up to twelve axes, comprises the steps of dividing the axes into two groups each composed of six axes or less, those axes which are positioned on one side of a dividing point (P) closely to a reference point serving as redundancy axes (11), those axes which are positioned on the other side of the dividing point closely to a robot wrist (Q) serving as basic axes (12), and controlling the dividing point (P), as a first control point, by way of interpolation and controlling the robot (Q), as a second control point, by way of interpolation with the controlled first control point regarded as a new reference point, so that all the axes of the articulated robot can be controlled by way of interpolation.

Abstract: In the program control of a robot intended for painting vehicles and in order to facilitate finding the numerous coating parameters stored in a robot movement program, coordination between the process parameter change point and the relevant coating parameters is to be obtained. To this end, and to establish a path of movement, an individual address is associated with each process parameter change point and, based upon the movement program, a separate parameter file is employed in which the relevant coating parameters are associated with the individual addresses. According to the subject method, the configuration of the workpiece to be coated is shown upon a display screen and, by utilizing the movement program, the selected process parameter change points are indicated visibly upon the workpiece shown.

Abstract: An adaptive controller for robots for driving an actuator of a robot arm under servo control where a servo constant is set such that the robot arm follows up a predetermined reference movement orbit. The controller has a switching section for switching between an adjustment mode where the servo constant is adjusted and a servo control mode where the servo constant is already set. Also included is a deviation supervising section for which obtains the deviation of an actual operation orbit of the robot arm from the reference movement orbit thereof, and operates the switching section to change the servo control mode into the servo adjustment mode when the obtained deviation exceeds a predetermined value. The controller also has a dynamic-characteristic-model identifying section for identifying the movement characteristic of the robot arm when the servo control mode is changed into the servo adjustment mode by the deviation supervising section and the switching section.

Abstract: A control circuit includes a microprocessor, a table store and an amplifier stage to control a controlled device which has a non-linear or linear, but discontinuous response curve. To obtain a linear response curve of the controlled device the table store is loaded with a response curve map in operating the controlled device. Thereafter the data loaded in pairs in the table store are inversely read-out and used as a control signal for the controlled device. The table store thus allows to linearize the response curve of the controlled device. In addition the data may be modified. According to the invention any correcting means to obtain an ideal response of the controlled device is eliminated. The invention provides for an optimum performance, smallest possible expenditure of circuitry and shortest possible control time.

Abstract: NC programs (11a-11d) are provided for corresponding ones of movable elements for prescribed axes, and the movable elements are moved by performing numerical control processing in numerical controllers (12a-12d) based on the NC programs. A plurality of axes to be synchronously controlled are designated by a synchronous axis command (SANC) inserted in the main NC program (11a), queuing commands (WNC) are inserted in the NC programs conforming to the movable elements which include the designated axes, and the corresponding movable elements are moved and controlled by performing numerical control processing while synchronization is achieved by the queuing commands.

Abstract: An NC data execution method which permits an efficient checking of the validity/invalidity of NC data through a simple operation. In an NC data execution process, a processor of an automatic programming apparatus reads out NC data, block by block, from a memory (S2), and determines whether or not the read NC data block satisfies an NC data execution interrupt condition, e.g., whether or not the data block contains a specific code (S3). When the interrupt condition is fulfilled, the data block is displayed at an input display field on the screen (S4), and then the NC data execution, including a graphic display operation based on the content of the data block satisfying the interrupt condition, e.g., a display of a tool path and the reading and display of the next block, is automatically interrupted, whereby the operator is allowed to thoroughly check the data block satisfying the interrupt condition.

Abstract: Herein disclosed are a method and an apparatus for indexing a moving portion of a robot to a mechanical origin. First and second reference holes are formed respectively in the moving portion and a holding portion supporting the moving portion relatively movably. A plug gauge used has a foot to be fitted in the first reference hole and a probe attached to the foot and sized to be inserted into the second reference hole. The plug gauge is fitted in the first reference hole, and the moving portion is then moved in a first direction relative to the holding portion by operating a drive unit. This relative movement of the moving portion is stopped when the probe of the plug gauge comes into contact with the inner wall of the second reference hole.