EP0132341A2
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EP
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Machine tool control
Assignee: AE PLC
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Filing: 1984-07-09
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Granted: —
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Expires: 2004-07-09
Abstract
Abstract A control system is provided for allowing complex shapes to be machined on a workpiece at high speed. The control system is computer (13) controlled and receives workpiece profile data which are converted into a succession of tool position signals during machining. Not all the digital signals are calculated at one time, a number of future digital signals are calculated during a succession of time intervals. In each time interval, a tool position signal is outputted which is of a constant amplitude corresponding to the required tool position and which is fed to a signal processor (19) where it is converted into a continuous signal which so changes progressively that at successive time intervals, equal to the time intervals of the tool position signals, the amplitude of the continuous signal is related to the successive values of the tool position signals. This continuous signal is fed to a closed-loop control system (22) which controls the movement of the tool holder in accordance with the continuous signal. The tool holder is of a type having a bandwidth sufficient to allow the required movements at the required speed. The control system has proportional and differential feedback (24, 25).
Inventors
- 👤 Walter Gwyn Edwards
- 👤 Robert John Holdsworth Winterbottom
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 04:08
CPC Classifications
B; B23; B23Q; B23Q15/00; G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/41
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
100 words
A control system for a machine tool in which a tool holder and a workpiece rotate relatively to one another during machining, of the kind comprising a computer (13) for producing from input data fed thereto, a succession of digital signals defining required successive tool holder positions to machine a workpiece to a predetermined profile, and characterised in that there is provided a signal processor (19) for converting said digital signals to a corresponding continuous signal, and a closed-loop continuous control system (22) for receiving the continuous signal and for controlling the movement of the tool holder in accordance therewith.
Claim 2
Dependent Claim
100 words
A control system for a machine tool in which a tool holder and a workpiece rotate relatively to one another during machining, of the kind comprising a computer (13) for producing from input data fed thereto, a succession of digital signals defining required successive tool holder positions to machine a workpiece to a predetermined profile, and characterised in that there is provided a signal processor (19) for converting said digital signals to a corresponding continuous signal, and a closed-loop continuous control system (22) for receiving the continuous signal and for controlling the movement of the tool holder in accordance therewith.
Claim 3
Dependent Claim
105 words
A control system according to claim 1, characterised in that the digital signals are produced during each of a succession of equal time intervals, each digital signal being converted into a tool position signal of constant amplitude corresponding to the value of the associated digital signal, the signal processor (19) producing the continuous signal from the succession of constant amplitude tool position signals, the continuous signal so changes progressively that at the end of successive time intervals, each equal to the time interval of the toll position signals, the amplitude of the continuous signal is related to the successive values of the tool position signals.
Claim 4
Dependent Claim
55 words
A control system according to claim 2, characterised in that each digital signal produced by the computer (13), in each time interval, is a group of bits representative of the required tool holder position for that interval, a digital-to-analogue converter (18) being provided for converting the group of bits into the tool holder position signals.
Claim 5
Dependent Claim
88 words
A control system according to claim 3, characterised in that the computer includes a store (14) for receiving input data defining a required workpiece profile, the computer (13), during at least some of said time intervals, producing, from said data, groups of bits corresponding to some of the required future tool holder positions, said groups being fed to the store (14), and the computer also outputting from said store during each time interval, a group of bits corresponding to the required tool holder position for that time interval.
Claim 6
Dependent Claim
59 words
A control system according to any one of claims 1 to 4, characterised in that there is further provided a workpiece position feedback (15) for feeding to the computer digital signals corresponding to the instantaneous position of the workpiece (10) relatively to a datum, the duration of said succession of equal time intervals being determined by said feedback signals.
Claim 7
Dependent Claim
89 words
A control system according to any one of claims 1 to 5 and characterised in that a workpiece is to be machined to a profile which is symmetrical about at least one plane including the axis of relative rotation of the workpiece and the tool holder, the computer (13) receiving data defining the workpiece profile for only one of the symmetrical portions, the computer (13) producing, from said data, tool holder position signals representative of required tool positions in both said one portion and the remaining portion or portions.
Claim 8
Dependent Claim
38 words
A control system according to any one of claims 1 to 6, characterised in that the closed-loop control system includes a linear motor (23) for receiving the continuous signal and for moving the tool holder in accordance therewith.
Claim 9
Independent Claim
103 words
A method of machining a workpiece using a tool holder, with the workpiece and the tool holder rotating relatively to one another, of the kind comprising feeding to a computer data defining a required profile of the workpiece, producing from the computer a succession of digital signals defining a succession of required tool holder positions to machine the workpiece to said profile, characterised in that said succession of digital signals are processed to produce a corresponding continuous signal, said continuous signal being fed to a closed-loop control system, and then the movement of the tool holder being controlled with said closed-loop control system.
Claim 10
Independent Claim
103 words
A method of machining a workpiece using a tool holder, with the workpiece and the tool holder rotating relatively to one another, of the kind comprising feeding to a computer data defining a required profile of the workpiece, producing from the computer a succession of digital signals defining a succession of required tool holder positions to machine the workpiece to said profile, characterised in that said succession of digital signals are processed to produce a corresponding continuous signal, said continuous signal being fed to a closed-loop control system, and then the movement of the tool holder being controlled with said closed-loop control system.
Claim 11
Dependent Claim
92 words
A method according to claim 8, characterised in that the method further includes producing from the succession of digital signals, in each of a corresponding succession of equal time intervals, a signal of constant amplitude corresponding to the digital signals, and processing said tool holder position signals to produce said continuous signal which so changes progressively that at the end of successive time intervals equal to the time intervals of the tool holder position signals, the amplitude of the signal is related to the successive values of the tool holder position signals.
Claim 12
Dependent Claim
108 words
A method according to claim 9, characterised in that the computer has fed thereto data defining the required profile of the workpiece at intervals which are greater than the intervals at which the digital signals are produced, the input data being stored in a store of the computer, the input data, during in at least some of the time intervals, being used to calculate future values of the tool holder position signals necessary to produce the required profile, said future values being fed to the store, and outputting, during each interval, the tool holder position signal corresponding to the required tool holder position in that interval being outputted.
Claim 13
Dependent Claim
78 words
ll. A method according to any one of claims 8 to 10, characterised in that a workpiece is machined to have a profile which is symmetrical about at least one plane including the axis of relative rotation between the tool and the workpiece, the method then comprising feed to the computer profile data defining the profile for one of said symmetrical portions and calculating within the computer, signals corresponding to required tool positions for all the symmetrical portions.
References Cited (Backward Citations)
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