Toshiba Kikai Kabushiki Kaisha

Minoru Hamamura

Jun Fujita

Sadaji Hayama

Kazuhiro Shiba

Takao Date

Kazuo Nagashima

Ichiro Matsumoto

Katsuhito Endo

Takahiro Funaki

Shigeichi Yamamoto

A servo motor controlling method includes: directly or indirectly detecting a position of a moving body which performs a circular-arc interpolation feeding motion by a servo motor; performing a feedback control for enabling the position of the moving body to comply with a position command; and at a quadrant changing time when a moving direction of the moving body is changed, performing torque correction on a torque command value according to a distance from a position where the moving direction is changed. By this method, a quadrant protrusion and a torque change with respect to a friction caused from a free zone at a time of reversion of a ball screw can be appropriately corrected. Especially, by performing a first torque correction for a static friction at the position where the moving direction is changed, and by performing a second torque correction for a moving friction after movement by the distance corresponding to the free zone, more appropriate correction can be obtained.

Servo motor controlling method

A numerical control device is disclosed having a parameter memory sectionB that stores discrete optimum parameters for respective operational modes, an operational mode setting switchto allow operational modes to be selectively set through user's operation, and a defect content setting means for registering defect contents of machined results. The optimum parameter, suited for a particular operational mode selected and set with the operational mode setting switch, is retrieved for executing setting of the parameter while enabling setting of the parameter based on information obtained with the defect content setting means.

Numerical control device

A position control apparatus and method has been devised which provides for an improved means of suppressing tracking error from a variable position reference occurring when a control object positioned via a transmission mechanism with mechanical transmission error resumes movement from a state stopped at a target position. A selection between two alternative tracking error compensating means within the control apparatus is made based on whether the detected position of the control object changes in a period after the control object stops and before the variable position reference is input again to a control deviation generating unit.

Position control apparatus and position control method

A portion ( ) of a chip remover ( ) is defined to be vibratory to give an NC machine tool (MT ) a vibration transferable onto a surface (FS) of a work ( ) under a finishing by the NC machine tool (MT ), a decision is made whether the NC machine tool (MT ) enters the finishing, and vibration of the vibratory portion ( ) is controlled, as the decision is true. A chip removal method and an NC machine tool equipped with a spiral chip remover ( ) as a chip remover have various chip removal rules for determining permission/prohibition of the operation of the spiral chip remover ( ). This spiral chip remover ( ) operates based on commands described in a machining program. When a command in the machining program is executed, the permission/prohibition of the operation of the spiral chip remover ( ) is controlled according to the chip removal rules.

Chip removal method and chip removal system for NC machine tools

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 as a controlled object and which ends with a detection of the re-start of the movement of the table . During the period, a correction amount for correcting a positional deviation E is issued.

Positional control system and positional control method

A feed velocity of a control axis and acceleration thereof do not exceed a maximum feed velocity and a maximum acceleration defined in mechanical specifications even if a radial operation is carried out for the purpose of a cut-in or escape operation in a contour describing control. A radial permissible maximum velocity (Vnp) and a radial permissible maximum acceleration ( np) in a contour describing control using a circular interpolation is set separately from a setting value of a maximum feed velocity (Vm) of a control axis and that of a maximum acceleration ( m) thereof set as mechanical specifications, and when a command of the circular interpolation is given, limitations are given to a radial velocity (Vn) and acceleration ( n) so that the radial velocity (Vn) and acceleration ( n) do not exceed the radial permissible maximum velocity (Vnp) and permissible maximum acceleration ( np).

Numerical controller and numerical control method for NC machine tools

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.

Lost motion correction system and lost motion correction method for numerical control machine tool

The servo control method operates a set value of a first-order lag time constant of a feedback compensation by both a detected mechanical position value and a transfer function corresponding to a change of an angular velocity about each axis under a multiple-axes simultaneous control. Further, the servo control method sets a feedforward amount so that the transfer function about the each axis is the same.

Servo control method

For an orbit boring to be performed by a tool ( ) in an orbital motion along an orbit (A), a permissible range of an acceleration (a) of the orbital motion is provided to meet a criterion of a machining precision of the orbit boring, and the acceleration (a) is controlled to be suppressed within the permissible range.

Controller and control method for orbit boring

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.

Numerical control apparatus and feed control processing method therefor

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.

Servo control method for orbital machining with cutting tool and servo

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.

Servo adjustment method and apparatus therefor

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.

Servo control method and servo control system for feed drive system

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.

Servo adjustment method and apparatus thereof

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.

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Shizuoka-ken, Japan

Minoru Hamamura