Abstract: A paint-out shape display method and an apparatus in a numerical control apparatus judges whether the inside of basic shapes divided for each shape element should be painted out or erased and in turn combines those basic shapes, thereby enabling a cross sectional shape of a rotating body to be displayed accurately. The cross sectional shape of the rotating body can be displayed properly, easily and at a high speed, and therefore the efficiency of a series of machining operations, beginning with program test, is greatly improved and a reduction in cost can be achieved.

Abstract: A method for determining a machining method in a numerical control information generating apparatus is realized by the steps of: dividing an area where recessed shapes overlap into a machining area where recessed shapes overlap and an area where recessed shapes do not overlap; determining a cutting tool for a machining area where recessed shapes do not overlap; determining whether or not the machining area where recessed shapes overlap can be cut by the same cutting tool, and combining the machining area where recessed shapes overlap with the machining area where recessed shapes do not overlap. As a result of this, machining modes can be determined automatically for a shape where recessed shapes overlap.

Abstract: A method whereby the numerical control information preparing function determines the manner of machining. On the basis of the input shape of a workpiece and on the basis of the input shape of a component part to be obtained from the workpiece, a portion of the workpiece which is to be subjected to outer diameter machining and a portion of the same which is to be subjected to inner diameter machining are determined. Thereafter, a division candidate point is obtained so that each of the portions may be divided, at the division candidate point, into a sub-portion to be subjected to forward cutting and a sub-portion to be subjected to backward cutting. On the basis of the configuration of the backward cutting sub-portion and the shape of the tool to be used, a check is made as to whether any part of the sub-portion can remain uncut after the backward cutting. On the basis of the result of this check, a determination is made as to whether the entire portion should be divided at the division candidate point.

Abstract: A spindle control system enables a gear change while a spindle is rotating by calculating the position of a motor shaft when gears are reengaged by a target position calculating circuit, and outputting speed commands for the motor shaft by a position control circuit based on the calculation result, and switching by a switching circuit so as to input the speed commands to a speed control circuit.

Abstract: A machining method is for determining numerical control information in a numerical control machine tool apparatus. A method includes inputting workpiece data denoting an initial shape of a workpiece which is to be machined, and further inputting product data denoting a desired final shape of the workpiece after it has been machined. Then, a machining area of the workpiece based on the workpiece data and the product data is determined. The thus determined machining area is divided into plural machining locations, and the numerical control information is prepared based on the plural machining locations. The workpiece is then machined based on the thus prepared numerical control information.

Abstract: A linear attuator of the present invention performs the fixing of a driving base by the primary fine means when the deflection of the moving velocity of the driving base in a driven direction and the moving velocity of the primary fine means driven by the secondary fine means in the driven direction becomes less than or equal to a specified allowable value, i.e., when the relating velocity becomes nearly zero, and moves the primary fine means driven by the secondary fine means in the direction opposite to that of the driven direction after not transferring the driving force of the secondary fine means to the driving base when the driving base is separated from the primary fine means. Thus, the driving base can be driven by a stroke longer than the driving stroke of the fine actuator itself at a specific velocity and it can be driven smoothly.

Abstract: A numerical control apparatus is characterized by a structure in which: a machining program stores the final shape of a work as well as the shape of a material; designates the outermost point (an apex) on the work in a direction opposing a cutting direction as a cutting reference point; sets linear lines which are respectively lowered from the cutting reference point by cutting depths, and obtains the inter-sections of the lines and the material shape. The intersections thus obtained are classified into points where the tool enters the work zone and points where the tool emerges from the work zone, so that the tool can be moved at a predetermined cutting rate for a cutting operation between the point where it enters and the point where it emerges from the work zone while it is moved at a rapid traverse rate between the emerging point and the point where it re-enters the work zone.

Abstract: A digitize control apparatus having a measuring function of the present invention determines a correct contact point between a stylus and a model on the basis of the displacement vector of a stylus obtained by a scanning head and a position vector indicating a machine coordinate value obtained by a position detecting apparatus, and therefore the influence of friction generated between a stylus and a model can be removed, thereby reducing error in the measurements.

Abstract: The tool feed rate correcting method for numerical control system and the apparatus therefor according to this invention correct the feed override values using an override correction coefficient which is calculated from the displacement information of the tool and control the tool feed rate so that machining loads can be maintained within predetermined range irrespective of the machining conditions. This invention is therefore effective in realizing machining with a high efficiency as well as in reducing the cost.

Abstract: An optical encoder of the present invention includes a first diffraction grating and a second diffraction grating which is displaceable relative to the first diffraction grating to detect the relative displacement. The second diffraction grating has a grating pattern which removes a component having a period which is a factor of 1/n (n: a positive odd number) of the period of a displacement signal representing the relative displacement. In the optical encoder according to the present invention, higher harmonic components are cancelled by adding the amounts of light which passes through the grating portions whose phase differs by a predetermined distance. Consequently, a non-distorted displacement signal can be obtained.

Abstract: In an averaged diffraction moire position detector of the present invention, diffracted lights which have passed through the same places as those through which measuring diffracted lights have passed are used for monitoring a quantity of light. Therefore, change in the quantity of light of a light source and change in the transmittance of diffraction gratings can be suitably corrected.

Abstract: An induction motor is controlled using a control device having a current control loop by detecting a current of the induction motor, and by detecting a current error corresponding to a difference between the detected current of the motor and a current command signal of the control device. The current error is processed to obtain a slip frequency. A field speed control command is generated based on the slip frequency and a motor speed of the induction motor.

Abstract: A position detecting apparatus detects the position of an object and includes a sensor device which outputs first and second AC detection signals which have a predetermined phase relationship and which correspond to a detected position of the object. An instantaneous value detecting unit detects and outputs instantaneous values of the first and second AC detection signals. A DC component detecting unit processes the instantaneous values to obtain first and second DC components of the first and second AC detection signals, respectively. A position calculating section calculates the position of the object based on a difference between the first DC component and the first AC detection signal, and a difference between the second DC component and the second AC detection signal.

Abstract: A tool retracting method and apparatus is for retracting a tool in an NC machine tool upon the detection of the occurrence of an abnormal machining condition during operation of the NC machine tool. The tool retraction direction is determined which is counter to the direction of the cutting load acting on the work at the moment of the occurrence of the machining abnormality, so that the tool can be promptly retracted without interfering with the work.

Abstract: The drive control apparatus for a linear actuator according to the present invention uses fine actuators, such as an electrostrictive element, so that it is possible to manufacture a linear actuator drive control apparatus obtaining big driving force in spite of a size considerably smaller than the conventional magnetic motor and linear motors utilized electromagnetic force. In addition, since the fine actuator and the driving base repeats their fixings and seperatings, it is possible to make the driven stroke range of the driving base wide. Since the fixing operation and the separating operation are carried out when the speeds of the fine actuator and of the driving base are almost the same, generation of the shock due to sudden speed change of the fine actuator and the driving base at the same of their fixing and separating is prevented, and it is possible to obtain smooth driving of the driving base.

Abstract: During synchronous control, a first servo motor controls a position of a first spindle system and a second spindle system having a second servo motor makes calculations for estimating the torque required for the second servo motor and gives a command, so that, when a rotational phase difference between the two servo motors exceeds a predetermined value, the rotational phase difference is made equal to zero by a rotational phase difference signal. A torque command to the first servo motor, an inertia ratio between the first and second servo motors, the rotational resistance of the two spindle systems and so on are input to a torque estimator which makes calculations for estimating the torque required for the second servo motor. The estimated torque is used to control the second servo motor. The two servo motors thus generate the appropriate torque when a work held between the two spindle systems is processed. It is therefore possible to significantly reduce the torsional torque applied to the work.

Abstract: A braking device for a rotary motor includes a braking member movably mounted to a non-rotating member of the rotary motor. The braking device further includes a compression spring coupled to the braking member for exerting a force on the braking member to cause the braking member to contact a rotating member of the rotary motor. The braking device further includes a piezoelectric element for actuating in response to a signal applied thereto to exert a force on the braking member to counteract the force applied to the braking member by the compression spring so as to cause the braking member to separate from the rotating member of the rotary motor.

Abstract: An absolute position detector for detecting an absolute position of a rotating shaft (1) includes a rotatable shaft and first gearing for operatively coupling the rotating shaft to the rotatable shaft (3a). Resolvers are provided, each having a stator and a rotor. The stator includes pole teeth made of a magnetic material and arranged along an outer circumference of the rotating shaft at a distance from the rotating shaft. The rotor includes a rotor made of a magnetic material respectively associated with pole teeth and located between the rotating shaft and pole teeth. Second gearing operatively couples the rotor of the resolvers to the rotatable shaft. Upon a rotation of the rotating shaft, the first gearing causes the rotatable shaft to rotate, and upon a rotation of the rotatable shaft, the second gearing (14 and 15) causes the rotor of each of the resolvers, at incrementally different gear ratios, to vary reluctance of a magnetic circuit formed by the pole teeth of an associated stator portion.

Abstract: For controlling the rotation angle of a main shaft of a numerical control machine tool in synchronization with the position of a feed shaft, the learning control method according to the present invention comprises steps of reading the positional command value of the feed shaft corresponding to the detected value of the current revolutional angle of said main shaft out of the table which stores in advance the positional instruction values corresponding to the angle equivalent to one rotation of the shaft, subtracting the detected value of the current position of the feed shaft from the read out positional value to obtain the positional deviation table of the shaft, renewing the correction value table of the positional deviation values of the shaft which are stored in advance by using afore-mentioned deviation table, and suspending the renewal operation of the correction table of the positional deviation when the difference between the positional deviation table which has been added with the correction value ta

Abstract: A linear encoder has a plurality short main scales arranged separately in their longitudinal direction and plural sliders situated in parallel with the longitudinal direction so as to more along these main scales. In operation, data obtained through these sliders are joined and processed in a signal processor in order to get position data of a table. Consequently, any position along a long movement stroke of the table can be detected easily and at a low cost.