Numerical control device with speed override control
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorYuji Mizukami
Life of this patent
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Abstract
A multi-system numerical control device which receives input commands for each system and is operative to control the speed and acceleration/deceleration of corresponding moveable objects, such as a motors. Each system has an interpolation unit and an acceleration/deceleration unit that is responsive to a corresponding time constant. A speed override device is operative to generate a speed reduction control signal that is applied to the interpolation unit to reduce the speed and to the acceleration/deceleration unit to reduce the time constant, thereby ensuring that the position relationship between the systems will not be lost even when override is applied.
Claims19
A numerical control device for a machine tool comprising:
- a plurality of controlled systems, the operation of at least a first and second of said systems being synchronized and being represented by respective acceleration/deceleration time constants;
- a speed override input for inputting a speed override command;
- an interpolation processor for reading a machining program and outputting resultant drive signals;
- a time-constant processor that modifies said respective acceleration/deceleration time constants for said first and second systems in response to said speed override command and in accordance with a predetermined functional relationship, and that outputs acceleration and deceleration control signals based on the modified time constants and the drive signals;
- wherein said functional relationship substantially maintains the synchronized operation of said first and second systems.
A numerical control device for a machine tool comprising:
- at least a first and a second controlled system, each comprising a moveable part and being responsive to input commands;
- means for providing a speed override to at least said first and said second controlled systems;
- speed calculating means, responsive to said speed override means, for producing a speed signal for controlling the speed of each said moveable part;
- and
- acceleration/deceleration means for providing acceleration and deceleration control signals for said first and second controlled systems for respective prescribed periods of time, said acceleration/deceleration means being responsive to said speed override means for modifying said prescribed periods of time in predetermined functional relationship to said provided speed override;
- wherein said functional relationship substantially maintains a positional relationship between said movable parts.
The method of controlling a plurality of systems in a numeral control device, each said system having a corresponding acceleration/deceleration time constant, in response to input control signals, comprising:
- generating respective speed control signals for each said system in response to said input control signals and at least one speed override command;
- and
- modifying each said time constant, in response to said speed override command, according to a predetermined functional relationship which substantially maintains a positional relationship between controlled portions of said systems.
A multi-line numerical control method for numerically controlling independent lines individually under control of independent machining programs, each said line having a respective acceleration/deceleration time constant and being operative to operate a motor, comprising the steps of:
- (a) analyzing each of said machining programs to identify a commanded feedrate for a corresponding line;
- (b) in response to said analysis, overriding each feedrate commanded by said each machining program analyzed at step (a) to provide respective override values;
- (c) calculating a modified corresponding acceleration/deceleration time constant to maintain positional relationships between the lines according to each override value at step (b);
- and
- (d) exercising acceleration/deceleration control of the motor on each line using each modified acceleration/deceleration time constant calculated at step (c).
A multi-line numerical control apparatus for numerically controlling independent lines individually under control of independent machining programs, each said line having a respective acceleration/deceleration time constant and being operative to operate a motor, comprising:
- (a) program analyzing means for analyzing each of said machining programs to identify a commanded feedrate for each said motor;
- (b) an overriding device for overriding each feedrate commanded by said each machining program analyzed by said program analyzing means;
- (c) acceleration/deceleration time constant calculating means for calculating a modified acceleration/deceleration time constant for each said line in order to maintain positional relationships between the lines according to each override value of said overriding device;
- and
- (d) accelerating/deceleration means for exercising the acceleration/deceleration control of a motor on each line using each modified acceleration/deceleration time constant calculated by said acceleration/deceleration time constant calculating means.
Dependencies are inferred from the claim text.