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 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: The invention relates to a numerical controlling unit 10 having a speed-feedback controlling system. A peak-frequency detector 20 determines a peak frequency from a characteristic of a frequency transfer function whose input is a speed-instruction input signal and whose output is a speed feedback signal. A band elimination component 30 conducts a band elimination process to the speed-instruction input signal, based on the peak frequency.

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 (9x and 9y) for detecting machine positions and motor position signals outputted from rotary encoders (7x and 7y) 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 (19x and 19y) as a dynamic lost motion correction value.

Abstract: For an orbital machining in which a spindle having a cutting tool attached thereto and a work to be machined are moved, by feed shaft control, to make a relative displacement to each other along a plane perpendicular to an axis of rotation of the spindle, such that a mutual interpolation motion is achieved between the spindle and the work, and a rotation angle of the spindle is controlled quantitatively and synchronously to have a predetermined correlation to the shaft control so that, at any angular position in rotation of the spindle, a blade direction of the cutting tool is maintained in a preset direction to thereby achieve a cutting into a configuration to be defined by an interpolation locus based on the mutual interpolation motion, there is effected a combination of feed-forward compensation for a follow-up delay in control of a motor servo system of a respective feed shaft and for a follow-up delay in control of a motor servo system of the spindle.

Abstract: Response delay error is calculated from an instructed position based on a position of a moving body and a position instruction to detect reversal of a servo motor and to compare response delay error produced in reversal of the servo motor and threshold value. In the case where response delay error is a threshold value or greater, the value of the already determined compensation torque is updated into a value that enables the response delay error to be decreased, and allows the moving body to carry out circular arc complementary feed motion under the same condition to compensate, based on the updated compensation torque, instructed torque for instructing the servo motor when reversal of the servo motor is detected. Compensating the instructed torque and updating the compensation torque is repeated until the response delay error is at the threshold value or less. Thus, a reasonable compensation torque is determined such that response delay error at the time of reversal of the servo motor is minimized.

Abstract: Letting a differential value of a command value of a position command to a position control loop be an input variable, a feed forward compensation value is calculated depending on the input variable and a combination of a proper vibration frequency and an attenuation constant of a vibration in a moving direction of a moving mechanism to be set in a parameter setting manner, and a feed forward compensation is effected for the command value of the position command to the position control loop by the feed forward compensation value.

Abstract: The variation of deviations of actual positions of a moving body from corresponding command positions is quantitatively evaluated as a servo control error, whether a feedback control system is oscillating is decided on the basis of the servo control error, set values of parameters expressing characteristics of a closed loop or a control element included in the feedback control system are adjusted on the basis of the result of the decision whether the feedback control system is oscillating, and the values of the parameters are adjusted to optimum values slightly different from values which will cause the feedback control system to oscillate.

Abstract: The position of a movable body driven for circular interpolation movement by servomotors is measured directly or indirectly, and the servomotors are controlled in a feedback control mode to drive the movable body for movement according to a position command signal. A torque signal at quadrant change in which the direction of movement of the movable body changes, and a maximum or minimum torque signal at a moment immediately after the reversion of the servomotor are detected, a reference torque for correction is determined on the basis of the difference between the torque signal value at quadrant change and the maximum or minimum torque command value, and the torque signal at quadrant change is corrected with reference to the reference torque.

Abstract: A method for displaying a circular interpolation locus which is used in a numerical control apparatus. The method is constituted by the steps of detecting movements of axes controlled by the numerical control apparatus, synthesizing signals detected in the detected step, displaying a movement locus of two axes as a circular interpolation locus on a display. A numerical control apparatus which has a circular interpolation locus display function is also disclosed. The numerical control apparatus is constituted by first detecting unit for detecting a motion of a control object controlled by a first servo motor, second servo detecting unit for detecting a motion of the control object by a second servo motor, two axes synthesizing unit for synthesizing the output signals for the first detecting unit for displaying the two axes movement locus. The method and apparatus can be applicable both semi-closed loop and hybrid control.

Abstract: In a hydrostatic pressure worm-rack device of the type comprising a worm formed with operating oil supply opening at the opposite flanks of respective teeth of the worm, opposite flanks of respective teeth of the rack being formed with oil pockets, there are provided an oil distributor mounted on one end of the worm shaft for supplying oil to mating surfaces and not mating surfaces of the teeth of the worm and rack and for supplying pilot oil to pilot oil supply ports provided for the flanks of the teeth at the opposite ends of the worm which firstly mate with the teeth of the rack.

Abstract: An attachment for fitting a tool to a hollow spindle of a machine tool, in a case where a shank portion of the tool has a taper-size smaller than that of a tapered hole of the spindle, comprises a hollow attachment body to be secured to the lower end of a ram of the machine tool, a sleeve rotatably supported in the attachment body, and an arbor assembly disposed axially movably in the sleeve. The arbor assembly comprises a stud arbor, a pull-stud to be engaged with a collet chuck disposed in the spindle, and a collet chuck to be engaged with a pull-stud of the tool inserted into a tapered hole of the sleeve.