US3668494A - Constant displacement stopping control - Google Patents

Constant displacement stopping control Download PDF

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Publication number
US3668494A
US3668494A US48249A US3668494DA US3668494A US 3668494 A US3668494 A US 3668494A US 48249 A US48249 A US 48249A US 3668494D A US3668494D A US 3668494DA US 3668494 A US3668494 A US 3668494A
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Prior art keywords
stop
phase
single shot
latch
motor
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Expired - Lifetime
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US48249A
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English (en)
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Gerald J Agin
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P3/00—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters
    • H02P3/06—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter
    • H02P3/08—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing a DC motor
    • H02P3/10—Arrangements for stopping or slowing electric motors, generators, or dynamo-electric converters for stopping or slowing an individual dynamo-electric motor or dynamo-electric converter for stopping or slowing a DC motor by reversal of supply connections

Definitions

  • ABSTRACT [52] U.S. Cl ..318/373, 318/612, 318/561 stopping f a 1. Servo m;- i ff t d in two phases, during [51 Int. Cl. .1102]! 3/10 the fi f which the velocity is brought to half its initial value [58] FIG!
  • FIG. 2b - ZERO VELOCITY TACHOMETER CONTROL FIG. 2b
  • FIG. 2C
  • This invention relates to d-c servo motors and it has reference in particular to a constant displacement stopping control for a d-c printed circuit motor driving a carriage for a printer.
  • incrementing of d-c servo motors has been effected by accelerating the motor quickly to a given velocity, maintaining this velocity by servo control, and then decelerating the motor quickly to a stop.
  • the deceleration is usually initiated by a signal from a displacement transducer (sometimes called a precoincidence signal), the length of the deceleration pulse being enough to bring the motors velocity to zero, this being determined by a fixed timing source such as a single shot, by a tachometer, or by a stop integrator such as disclosed in the IBM Technical Disclosure Bulletin for May 1969, on page 1,697.
  • Another object of the invention is to provide for using a velocity detector which fires twice during stopping to reset a stop latch during the two phases of a stopping sequence fora d-c servo motor.
  • An important object of the invention is to provide for using a reference single shot and a proportional single shot to set a stop latch during the second phase of a two-phase stopping sequence for a d-c servo motor.
  • Yet another object of the invention is to provide for using a half-velocity detector for resetting a stop latch during a d-c servo motor stopping sequence.
  • FIG. 4 shows a plurality of timing curves and a typical motor velocity waveform illustrating the operation of the stop control of FIG. 3.
  • FIG. 5 shows curves illustrating the stopping velocity waveform of the stop control circuit of FIG. 3 as a function of temperature.
  • FIG. 6 is a more detailed schematic block diagram of a constant displacement stop control system for a d-c servo motor embodying the invention.
  • FIGS. 7a through 7c show timing curves illustrating the operation of the stop control system of FIG. 6 under difierent temperature conditions.
  • FIG. 8 illustrates a velocity waveform used in connection with the derivation of an optimum proportional single shot ratio covered in the appendix.
  • a common method of incrementing d-c servo motors is to accelerate the motor quickly to a given velocity, maintain this velocity by servo control, then to decelerate quickly to a stop.
  • a typical velo'city waveform is shown in FIG. 1.
  • the deceleration is usually initiated by a signal from a displacement transducer (sometimes called a precoincidence signal).
  • the length of the deceleration pulse should be enough to bring the motor's velocity exactly to zero, and may be controlled by a fixed timing source (single shot), by a tachometer, or by a stop integrator such as described in the IBM Technical Disclosure Bulletin for May 1969, on page 1,697.
  • the system of the present invention makes use of the pro portional single shot of U. S. Pat. No. 3,541,418, which issued Nov. 17, 1970, to Gerald J. Agin et al, entitled Proportional Damping for Motor Drive," application Ser. No. 665,5 39, filed Sept. 5, 1967. Its operation may be summarized as follows: An input pulse charges a capacitor to a level determined by the length of the pulse. During the discharge of the capacitor the output is switched; the length of the output pulse is determined by the level the capacitor was charged to by the input pulse. The ratio of output pulse length to input pulse length is equal to the ratio between'the discharging and charging time constants of the circuit.
  • FIG. 3 A simplified logic circuit diagram of a constant displacement deceleration system embodying the invention is shown in FIG. 3 and its waveforms in FIG. 4.
  • a Stop latch 10 is provided to control the Driver 11 for a Servo Motor 13 in order to supply; reverse drive thereto for stopping.
  • the Stop latch 10 is set in response to termination of a Go or Not Stop signal from a servo latch (not shown), which is applied to set the latch through an OR 12, Inverter 14, and Single Shot 16.
  • the same servo latch signal is applied to an Inverter l8 and a Reference Single Shot 20 to gate the Off output of the Stop latch 10 in AND 22 for controlling a Proportional Single Shot 24, to provide a signal through OR 26 back to OR 12 to again set the Stop latch 10.
  • the Stop latch 10 is reset by applying the On output of the latch 10 through a Half-Velocity Detector 30 such as, for example, the current integrator described in the IBM Technical Disclosure Bulletin for May I969 on page 1,697, with the charging rate doubled.
  • a Half-Velocity Detector 30 such as, for example, the current integrator described in the IBM Technical Disclosure Bulletin for May I969 on page 1,697, with the charging rate doubled.
  • the present circuit utilizes the Half-velocity Detector 30, which fires twice.
  • the Detector 30 is connected to a Resistor 31 in the armature circuit of the Motor 13 to respond to a predetermined integral of deceleration (change in motor velocity), such as, for example, half the normal velocity of the motor.
  • the first phase of the stopping sequence is initiated by the termination of the Not Stop or Go signal from the servo latch, which provides an output from the Inverter 18 to start the end of the Reference single shot pulse.
  • the Proportional single shot capacitor is charged during the interval between the end of the first stopping phase and the timeout of the Reference Single Shot 20. If the ratio of its time constants is unity, the second stopping phase will begin at an equal interval after the timeout of the Reference Single Shot 20.
  • the result of this action is to introduce a coasting interval in the middle of the stopping sequence. If the motor is warm and its deceleration low, it will take longer to reach half velocity and travel farther to reach it than when the motor is cold and its deceleration high. However, the additional coasting displacement at half velocity, when the motor is cold, should exactly make up forthe difference in displacement.
  • FIG. shows the constancy of displacement in a different way.
  • Two velocity wavefomis are shown: one for hot and one for cold operation.
  • the difierence in displacement is the area between the two curves. But this area is the sum of the two shaded areas of the figure, one a positive area (with hot wavefonn above) and one for a negative area (with the cold waveform above). Since the two shaded areas are equal, their sum will be zero, and the displacement on stopping will not be afunction of deceleration rate.
  • the ratio of the time constants of the Proportional single shot will have to be adjusted to other than unity.
  • the optimum ratio is (l aI/a2 )/2 where a1 is the deceleration rate during the first phase of stopping, and a2 is the deceleration rate during the second phase.
  • a1 is the deceleration rate during the first phase of stopping
  • a2 is the deceleration rate during the second phase.
  • the logic circuit of FIG. 3 is partially incomplete in that no provision is made for the case where the first phase of deceleration approaches the length of the reference single shot.
  • FIG. 6 shows the complete control system necessary to implement constant displacement stopping
  • FIG. 7 shows its waveforms under various operating conditions.
  • the additional features over what is shown in FIG. 3 include I an Oscillator 32 for applying pulses through a Duty-Cycle Single Shot 34, OR 36, and AND 38 to the motor Driver 11 to give a variable rate of deceleration (dependent on the duty cycle), (2) a First Phase latch 40, which is connected to be set by the Not Stop or Go signal from the servo latch to override a pulsed drive from Oscillator 32 and provide a dc level signal through the AND 38 in conjunction with the On output of the Stop latch 10, (3) a Recovery Single Shot 42, which connects the Off output of the First Phase latch 40 through OR 26A to control set of the Stop latch through Inverter 28 and Single Shot 29 to guarantee the Stop Integrator 30 sufficient time to discharge for the next cycle, (4) the First Phase latch 40 and the Recovery Single Shot 42 together guarantee that if the first phase of stopping overruns the Reference Single Shot 20 signal and the Pro
  • a useful byproduct of this method of stopping is that the final stopping position may be adjusted with respect to the position of the precoincidence signal by varying the Reference Single Shot 20 instead of mechanically moving a displacement transducer, which provides the precoincidence signal as was done heretofore.
  • a termination of the Not Stop or Go signal from the servo latch turns on the Reference Single Shot 20 through the Inverter 18.
  • the Stop latch I0 is set through the OR 26A, Inverter 28, and the Single Shot 29 so as to gate an output from AND 38.
  • the Stop latch I0 When the Stop latch I0 is first set, the First Phase latch 40 will still be on, and the pulse drive from the Oscillator 32 will be overridden by the d -c level output of the First Phase latch 40 through OR 36 to maintain a solid drive through AND 38 to the Driver 1 l for decelerating the Motor 13.
  • the Stop latch 10 and the First Phase latch 40 are reset by the Stop Integrator 30 to terminate the first phase of the stopping sequence.
  • the Proportional Single Shot 24 times out and through OR 26A, Inverter 48, and Single Shot 50, again sets the Stop latch 10.
  • Stop latch 10 gates the pulse output of the Oscillator 32 through the Duty-Cycle Single Shot 34, OR 36, and AND 38 to provide a pulsed drive to the driver during the second phase of the stopping sequence.
  • the Stop latch 10 is again reset by the Stop Integrator 30 .to terminate the sequence.
  • a control circuit embodying the invention is capable of extremely accurate positioning and is substantially independent of temperature effects. While the Stop Integrator has been described as a Half-velocity Detector, other predetermined proportions may be used as desired.
  • bistable switch means connected to said driver circuit means operable to turn on said driver circuit means to provide reverse energization of said motor armature for stopping said motor
  • circuit means connected to said bistable switch means for effecting operation thereof a first time in response to a stop signal to start a first phase of a stop sequence
  • bistable switch means connected to said bistable switch means to render said bistable switch means operable a second time to start a second phase in the stop sequence, said integrating means operating to again render said bistable switch means inoperative and terminate said second phase and provide a second phase having a duration detem'iined by the value of the armature current during said second phase.
  • bistable switch means comprising a stop latch having set and reset operating conditions
  • additional circuit means comprising a reference single shot connected to respond to said stop signal and a proportional single shot connected to said reference single shot and to said stop latch to be activated by said stop latch being reset.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Stopping Of Electric Motors (AREA)
  • Feedback Control In General (AREA)
  • Control Of Electric Motors In General (AREA)
  • Character Spaces And Line Spaces In Printers (AREA)
US48249A 1970-06-22 1970-06-22 Constant displacement stopping control Expired - Lifetime US3668494A (en)

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JP (1) JPS5144724B1 (enrdf_load_html_response)
DE (1) DE2128943A1 (enrdf_load_html_response)
FR (1) FR2095584A5 (enrdf_load_html_response)
GB (1) GB1317673A (enrdf_load_html_response)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748566A (en) * 1970-02-28 1973-07-24 Licentia Gmbh Stepping motor with compensated angular error
US3809986A (en) * 1972-02-18 1974-05-07 Philips Corp Positioning device
US3924170A (en) * 1973-07-31 1975-12-02 Int Computers Ltd Bang-bang servo system
US4023080A (en) * 1975-03-26 1977-05-10 Fuji Xerox Co., Ltd. Phase synchronizing circuit
US4166970A (en) * 1975-12-24 1979-09-04 Compagnie Internationale pour l'Information Cii Honeywell Bull Apparatus and method for shifting a head movable relative to a carrier for recorded information
US4460857A (en) * 1983-05-31 1984-07-17 Rca Corporation Encoder controlled apparatus for dynamic braking
US4682822A (en) * 1983-12-31 1987-07-28 Marabuwerke Erwin Martz Gmbh & Co Electronic carriage brake for a drawing machine
EP0322177A3 (en) * 1987-12-19 1990-05-30 Pioneer Electronic Corporation Spindle motor stop control device

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5158610A (enrdf_load_html_response) * 1974-11-15 1976-05-22 Yamato Sewing Machine Mfg
JPS5359815A (en) * 1976-11-10 1978-05-30 Fujitsu Ltd Motor stop controlling system
FR2470506A1 (fr) * 1979-11-27 1981-05-29 Thomson Brandt Dispositif de freinage d'un moteur de rotation, et lecteur de videodisque comprenant un tel dispositif
JPS59156174A (ja) * 1983-02-24 1984-09-05 West Electric Co Ltd モ−タ駆動制御装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2821672A (en) * 1952-08-25 1958-01-28 Siemens Ag Electric control systems for elevators, particularly high-speed passenger elevators and the like
US2846026A (en) * 1955-10-05 1958-08-05 Asea Ab Elevator control system
US3154730A (en) * 1961-03-14 1964-10-27 Ibm Speed control of a d. c. motor
US3240290A (en) * 1962-08-13 1966-03-15 Dover Corp High and low speed leveling control for an elevator with tach speed sensor
US3500163A (en) * 1967-03-02 1970-03-10 Potter Instrument Co Inc Motor control circuit
US3541418A (en) * 1967-09-05 1970-11-17 Ibm Proportional damping for motor drive

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2821672A (en) * 1952-08-25 1958-01-28 Siemens Ag Electric control systems for elevators, particularly high-speed passenger elevators and the like
US2846026A (en) * 1955-10-05 1958-08-05 Asea Ab Elevator control system
US3154730A (en) * 1961-03-14 1964-10-27 Ibm Speed control of a d. c. motor
US3240290A (en) * 1962-08-13 1966-03-15 Dover Corp High and low speed leveling control for an elevator with tach speed sensor
US3500163A (en) * 1967-03-02 1970-03-10 Potter Instrument Co Inc Motor control circuit
US3541418A (en) * 1967-09-05 1970-11-17 Ibm Proportional damping for motor drive

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3748566A (en) * 1970-02-28 1973-07-24 Licentia Gmbh Stepping motor with compensated angular error
US3809986A (en) * 1972-02-18 1974-05-07 Philips Corp Positioning device
US3924170A (en) * 1973-07-31 1975-12-02 Int Computers Ltd Bang-bang servo system
US4023080A (en) * 1975-03-26 1977-05-10 Fuji Xerox Co., Ltd. Phase synchronizing circuit
US4166970A (en) * 1975-12-24 1979-09-04 Compagnie Internationale pour l'Information Cii Honeywell Bull Apparatus and method for shifting a head movable relative to a carrier for recorded information
US4460857A (en) * 1983-05-31 1984-07-17 Rca Corporation Encoder controlled apparatus for dynamic braking
US4682822A (en) * 1983-12-31 1987-07-28 Marabuwerke Erwin Martz Gmbh & Co Electronic carriage brake for a drawing machine
EP0322177A3 (en) * 1987-12-19 1990-05-30 Pioneer Electronic Corporation Spindle motor stop control device

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JPS5144724B1 (enrdf_load_html_response) 1976-11-30
JPS471165A (enrdf_load_html_response) 1972-01-20
DE2128943A1 (de) 1971-12-30
GB1317673A (en) 1973-05-23
FR2095584A5 (enrdf_load_html_response) 1972-02-11

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