EP0300823A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Incremental positioning system
Assignee: HP Inc
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Filing: 1988-07-22
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Granted: —
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Expires: 2008-07-22
Abstract
Abstract A control system providing a control of position, velocity, and direction of movement of a member in an axis of freedom which employs a scale (13) having scale divisions (13a) thereon and bands or zones (A,B,C) defining limits of constant velocity control, acceleration and deceleration zone limits, and a rest or parking position. The scale spans and parallels the axis of freedom. A single channel transducer or encoder (12) mounted on and moving with the member produces time varying output signals in response to the sensing of scale divisions along the scale and signals of different characteristic in response to encoder sensing of the limit bands. The time varying output signals are employed as scale division count signals for position determination and as scale division count signals per unit of time, for velocity feed-back. The signals of different characteristic produced upon entering and during crossing of the limit bands, are utilized in a system of logic for computing control sytem signals to compensate control uncertainties in differing functional modes of the control system.
Inventors
- 👤 Mark W. Majette
- 👤 John A. Wickeraad
- 👤 William J. Walsh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 14:14
CPC Classifications
G; G05; G05D; G05D3/00; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/21; G05B19/23; G05B19/231; B; B41; B41J; B41J19/00; B41J19/18; B41J19/20; B41J19/202; B41J19/205; B41J19/207; G01; G01D; G01D5/00; G01D5/12; G01D5/244; G01D5/245; G01D5/2454; G01D5/2455; G01D5/2457; G06; G06K; G06K15/00; G06K15/22; G05B2219/00; G05B2219/30; G05B2219/37; G05B2219/37153; G05B2219/37296; G05B2219/42; G05B2219/42118; G05B2219/42237; G05B2219/43; G05B2219/43008; G05B2219/45; G05B2219/45187
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
135 words
A distance measuring device for controlling movement of a work element means along a path, comprising a stationary scale (13) with equally spaced marks (13a) extending along the path, a scale detector (12) associated with the work element means and movable adjacent the scale (13) to detect the marks (13a) and produce a time varying voltage, and a control system employing the time varying voltage as a measure of movement along the path to provide work commands for the work element means, characterised in that the scale has a pair of spaced work limit bands (B) of greater length along the path than the marks (13a) and which produce a steady state voltage in the detector (12), which voltage is used by the control system to provide further work commands for the work element means.
Claim 2
Dependent Claim
135 words
A distance measuring device for controlling movement of a work element means along a path, comprising a stationary scale (13) with equally spaced marks (13a) extending along the path, a scale detector (12) associated with the work element means and movable adjacent the scale (13) to detect the marks (13a) and produce a time varying voltage, and a control system employing the time varying voltage as a measure of movement along the path to provide work commands for the work element means, characterised in that the scale has a pair of spaced work limit bands (B) of greater length along the path than the marks (13a) and which produce a steady state voltage in the detector (12), which voltage is used by the control system to provide further work commands for the work element means.
Claim 3
Independent Claim
292 words
A device having work element means movable along a path in an axis for performing a work function within predetermined limits of movement in said axis, motor means (9) for driving said work element means and a control system (2,4) for operating said motor means in response to work commands, the improvement comprising: a stationary scale (13) paralleling said axis with equally spaced marks (13a) along it; a pair of spaced work limit bands (B) on said scale, each having a dimension along said scale greater than that of each of said marks (13a); a scale detector (12) connected to and movable with said work element adjacent said scale; to produce a time varying voltage in traversing each mark and the space adjacent thereto, and a work limit steady state voltage upon detection of a work limit band, said steady state voltage existing while said detector remains in said work limit band; means connecting said scale detector (12) to said control system to supply said time varying voltage and said work limit steady state voltage thereto; means in said control system (2,4) responsive to said work commands for operating said motor means (9) to move said work element means in said axis and detector along said scale; and means in said control system responsive to a first work limit steady state voltage of said detector while crossing a first of said work limit bands, to initiate a work function of said work element means upon the occurrence thereafter of a time varying voltage of said detector, and for terminating said work function of said work element means upon a second occurrence of said work limit steady state voltage of said detector when said detector detects the other of said work limit bands.
Claim 4
Independent Claim
292 words
A device having work element means movable along a path in an axis for performing a work function within predetermined limits of movement in said axis, motor means (9) for driving said work element means and a control system (2,4) for operating said motor means in response to work commands, the improvement comprising: a stationary scale (13) paralleling said axis with equally spaced marks (13a) along it; a pair of spaced work limit bands (B) on said scale, each having a dimension along said scale greater than that of each of said marks (13a); a scale detector (12) connected to and movable with said work element adjacent said scale; to produce a time varying voltage in traversing each mark and the space adjacent thereto, and a work limit steady state voltage upon detection of a work limit band, said steady state voltage existing while said detector remains in said work limit band; means connecting said scale detector (12) to said control system to supply said time varying voltage and said work limit steady state voltage thereto; means in said control system (2,4) responsive to said work commands for operating said motor means (9) to move said work element means in said axis and detector along said scale; and means in said control system responsive to a first work limit steady state voltage of said detector while crossing a first of said work limit bands, to initiate a work function of said work element means upon the occurrence thereafter of a time varying voltage of said detector, and for terminating said work function of said work element means upon a second occurrence of said work limit steady state voltage of said detector when said detector detects the other of said work limit bands.
Claim 5
Dependent Claim
155 words
A device according to Claim 1, comprising: a pair of sweep limit bands (A) on said scale, each being disposed between a work limit band and the adjacent end of said scale and each having a dimension along said scale greater than that of each of said marks (13a); equally spaced marks (13a) on said scale between each work limit band (B) and each sweep limit band (A), defining equal scale divisions therebetween; said detector producing a sweep limit steady state voltage upon entering a sweep limit band (A); and means in said control system responsive to said second occurrence of said work limit steady state voltage for operating said motor means (9) to decelerate said work element means and to stop said work element means in said sweep limit band (B) in response to the occurrence and existence of said sweep limit steady state voltage when said detector detects said sweep limit band (A).
Claim 6
Dependent Claim
88 words
A device according to Claim 2, comprising: means in said control system responsive to the presence of a work command after the occurrence of said sweep limit steady state voltage for operating said motor means to reverse the direction of movement of said work element means; and means in said control system for applying voltages to said motor means for accelerating said work element means to a desired speed in the space along said scale between said sweep limit band (A) and the adjacent work limit band (B).
Claim 7
Independent Claim
107 words
A device according to any preceding Claim, comprising: means responsive to said time varying voltages for producing first pulses having a pulse count per inch of scale related to the number of scale divisions per inch of scale; means responsive to said first pulses for producing second pulses with twice the pulse count of the first and for producing third pulses having four times the pulse count of the first; means for applying said third pulses as feedback in said control system; and means for applying said second pulses to the work element means when it lies between within limits set by the work limit bands (B).
Claim 8
Independent Claim
36 words
A device according to any preceding Claim, wherein said work commands move said work element at a first constant speed in said path between the first and second occurrences of said work limit steady state voltage.
Claim 9
Dependent Claim
64 words
A device according to Claim 6, comprising: means in said control system responsive to a work command to reverse said work element between the occurrence of said first and said second work limit steady state voltages, for decelerating said work element means to a second speed less than the first speed and thereafter for holding said motor means inoperative for a predetermined time period.
Claim 10
Dependent Claim
44 words
A device according to Claim 7, comprising: means in said control system responsive to said time varying voltages for producing four voltage pulses with the occurrence of each time varying voltage, said voltage pulses holding said motor means inoperative for said predetermined time period.
Claim 11
Dependent Claim
37 words
A device according to Claim 8, wherein: said predetermined time period comprises 5 time intervals each of which is determined by the time between said voltage pulses when said work element means is moving at constant speed.
Claim 12
Dependent Claim
62 words
A device according to Claim 4, comprising: means in said control system responsive to the first occurrence of said work limit steady state voltage during acceleration of said work element means to desired speed and after the occurrence of said time varying voltage of said detector for delaying initiation of said work function for a predetermined number of time varying voltage cycles.
Claim 13
Independent Claim
18 words
A device as claimed in any preceding Claim wherein the work element means is a thermal inkjet head.
Claim 14
Dependent Claim
175 words
An incremental positioning system for a device having a carriage movable along a path, a work element means on said carriage, a scale along said path having equal scale divisions and a scale detector on said carriage for reading said scale, comprising: a control system coupled to said carriage for moving said carriage along said path; means for applying incremental position commands to said control system to move said carriage; means responsive to the output of said scale detector when moving along said scale for forming first pulses having a pulse count per inch of scale related to the number of scale divisions per inch of scale, for forming second pulses having a pulse count twice that of the first and for forming third pulses having a pulse count equal to four times the first; means for coupling said third pulses as feedback to said control system when the pulse rate is above a predetermined mined minimum pulse rate; and means for coupling said second pulses to said work element means for causing its actuation.
Claim 15
Dependent Claim
175 words
An incremental positioning system for a device having a carriage movable along a path, a work element means on said carriage, a scale along said path having equal scale divisions and a scale detector on said carriage for reading said scale, comprising: a control system coupled to said carriage for moving said carriage along said path; means for applying incremental position commands to said control system to move said carriage; means responsive to the output of said scale detector when moving along said scale for forming first pulses having a pulse count per inch of scale related to the number of scale divisions per inch of scale, for forming second pulses having a pulse count twice that of the first and for forming third pulses having a pulse count equal to four times the first; means for coupling said third pulses as feedback to said control system when the pulse rate is above a predetermined mined minimum pulse rate; and means for coupling said second pulses to said work element means for causing its actuation.
References Cited (Backward Citations)
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