US3737751A — Servomechanism stop control

Claim 1

Independent Claim 188 words

In a motor velocity servomechanism having motor feedback transducer means, means responsive to a GO command to accelerate the motor and to thereafter control motor velocity to a desired running value, and means responsive to a STOP command to decelerate the motor from the running value to zero velocity in a preselected manner; an improved deceleration control apparatus comprising; means responsive to the occurrence of said STOP command to energize said motor in a manner to achieve forced deceleration thereof, distance measuring means responsive to the distance traversed by said motor after the occurrence of said STOP command, means storing a nominal velocity-versus-distance stopping profile for said motor to thereby define the preselected manner of controlling the motor''s velocity from the running value to zero, comparison means receiving as inputs the actual motor velocity and said stopping profile, and controlled by said distance measuring means to compare actual motor velocity at a known distance to the nominal motor velocity which should exist at that distance, and means controlled by said comparison means and effective to variably control said motor energization in a manner to achieve said stopping profile.

Claim 2

Dependent Claim 188 words

In a motor velocity servomechanism having motor feedback transducer means, means responsive to a GO command to accelerate the motor and to thereafter control motor velocity to a desired running value, and means responsive to a STOP command to decelerate the motor from the running value to zero velocity in a preselected manner; an improved deceleration control apparatus comprising; means responsive to the occurrence of said STOP command to energize said motor in a manner to achieve forced deceleration thereof, distance measuring means responsive to the distance traversed by said motor after the occurrence of said STOP command, means storing a nominal velocity-versus-distance stopping profile for said motor to thereby define the preselected manner of controlling the motor''s velocity from the running value to zero, comparison means receiving as inputs the actual motor velocity and said stopping profile, and controlled by said distance measuring means to compare actual motor velocity at a known distance to the nominal motor velocity which should exist at that distance, and means controlled by said comparison means and effective to variably control said motor energization in a manner to achieve said stopping profile.

Claim 3

Dependent Claim 49 words

A motor servomechanism as defined in claim 1 wherein said distance measuring means is effective to establish a plurality of distance checkpoints at which said comparison means is effective to compare actual motor velocity at each distance checkpoint to a different nominal motor velocity at each of said checkpoints.

Claim 4

Dependent Claim 61 words

A motor servomechanism as defined in claim 2 wherein said motor is a direct current motor and said forced deceleration is a plugging mode of energization, and including means controlled by said distance measuring means to inhibit motor plugging energization while the actual motor velocity is greater than zero, and including means to thereafter dynamically brake said motor to zero velocity.

Claim 5

Independent Claim 108 words

The method of speed controlling the stopping distance of DC motor comprising the steps of; responding to a motor STOP command and instituting plugging as a result thereof, measuring the distance traveled by the motor after the occurrence of the STOP command and selecting certain distances as speed checkpoints, making a comparison of actual motor speed at each checkpoint to a nominal speed which should exist at that checkpoint, deriving a speed error signal as a result of said comparison, and adjusting the mode of plugging as a function of said error signal and in a manner devised to achieve the desired nominal speed at the next checkpoint.

Claim 6

Independent Claim 108 words

The method of speed controlling the stopping distance of DC motor comprising the steps of; responding to a motor STOP command and instituting plugging as a result thereof, measuring the distance traveled by the motor after the occurrence of the STOP command and selecting certain distances as speed checkpoints, making a comparison of actual motor speed at each checkpoint to a nominal speed which should exist at that checkpoint, deriving a speed error signal as a result of said comparison, and adjusting the mode of plugging as a function of said error signal and in a manner devised to achieve the desired nominal speed at the next checkpoint.

Claim 7

Dependent Claim 29 words

The method as defined in claim 4 including the step of selecting a final checkpoint which is shorter than said stopping distance and terminating plugging as a function thereof.

Claim 8

Dependent Claim 20 words

The method as defined in claim 5 including the step of dynamically braking the motor subsequent to said final checkpoint.

Claim 9

Dependent Claim 139 words

Servomechanism stop control apparatus for use in reducing the velocity of a direct current motor from a known running velocity to zero velocity in a given distance, comprising; means defining an optimum velocity-versus-distance stopping curve for said motor, means responsive to a desire to stop said motor and effective thereupon to institute plugging of said motor, disTance measuring means controlled by said motor, velocity measuring means controlled by said motor, comparison means controlled by said distance measuring means, and receiving as inputs said optimum stopping curve and said velocity measuring means, said comparison means being effective to compare actual motor velocity to an optimum motor velocity defined by said stopping curve, and means controlled by said comparison means in accordance with said comparison to adjust the plugging of said motor in a manner devised to achieve said stopping curve.

Claim 10

Dependent Claim 139 words

Servomechanism stop control apparatus for use in reducing the velocity of a direct current motor from a known running velocity to zero velocity in a given distance, comprising; means defining an optimum velocity-versus-distance stopping curve for said motor, means responsive to a desire to stop said motor and effective thereupon to institute plugging of said motor, disTance measuring means controlled by said motor, velocity measuring means controlled by said motor, comparison means controlled by said distance measuring means, and receiving as inputs said optimum stopping curve and said velocity measuring means, said comparison means being effective to compare actual motor velocity to an optimum motor velocity defined by said stopping curve, and means controlled by said comparison means in accordance with said comparison to adjust the plugging of said motor in a manner devised to achieve said stopping curve.

Claim 11

Dependent Claim 50 words

A servomechanism as defined in claim 7 wherein said comparison means is controlled by said distance measuring means at a plurality of selected distances, and wherein said last named means adjusts the plugging of said motor in a manner devised to achieve said stopping curve at a subsequent distance checkpoint.

Claim 12

Dependent Claim 47 words

A servomechanism as defined in claim 8 including dynamic brake means effective to dynamically brake said motor to a stop, said dynamic brake means being rendered effective by said distance measuring means upon said motor reaching a final checkpoint at a distance less than said given distance.

Claim 13

Dependent Claim 156 words

In a data processing magnetic tape unit having a capstan, a direct current high torque - low inertia motor directly connected to the capstan, and tension means holding a length of tape in continuous engagement with the capstan; deceleration control apparatus to control the capstan stopping velocity in the interblock gap between blocks of tape data, comprising; means defining a desired capstan velocity-versus-stopping distance curve to control the length of the interblock gap, capstam distance measuring means, capstan velocity measuring means, control means for said motor receiving as inputs said first named means and said velocity measuring means, and being controlled by said distance measuring means to variably plug said motor in a manner devised to achieve the desired capstan velocity-versus-stopping distance curve during deceleration of said motor, and means responsive to said capstan traversing a distance less than said stopping distance and effective to terminate plugging of said motor and to institute dynamic braking thereof.

Claim 14

Dependent Claim 156 words

In a data processing magnetic tape unit having a capstan, a direct current high torque - low inertia motor directly connected to the capstan, and tension means holding a length of tape in continuous engagement with the capstan; deceleration control apparatus to control the capstan stopping velocity in the interblock gap between blocks of tape data, comprising; means defining a desired capstan velocity-versus-stopping distance curve to control the length of the interblock gap, capstam distance measuring means, capstan velocity measuring means, control means for said motor receiving as inputs said first named means and said velocity measuring means, and being controlled by said distance measuring means to variably plug said motor in a manner devised to achieve the desired capstan velocity-versus-stopping distance curve during deceleration of said motor, and means responsive to said capstan traversing a distance less than said stopping distance and effective to terminate plugging of said motor and to institute dynamic braking thereof.

Claim 15

Dependent Claim 50 words

A magnetic tape unit as defined in claim 10 wherein said distance measuring means establishes a plurality of discretely spaced distance checkpoints, and wherein said control means variably controls said motor at each checkpoint in a manner devised to achieve the desired capstan velocity-versus-stopping distance curve at a subsequent checkpoint.

Claim 16

Dependent Claim 122 words

Stop control servomechanism apparatus, comprising; a motor whose stopping distance is to be controlled from a known velocity to zero velocity in accordance with a preselected velocity-versus-distance profile, means establishing said preselected velocity-versus-distance profile as a control reference, motor distance measuring means providing an output at a plurality of discrete distance checkpoints, motor velocity measuring means, and control means for said motor receiving as inputs said first named means and said velocity measuring means, and being controlled by said distance measuring means to compare said motor velocity to said control reference in accordance with the known distance parameter and to variably control said motor at each distance checkpoint in a manner devised to achieve the profile velocity at a subsequent distance checkpoint.

Claim 17

Dependent Claim 122 words

Stop control servomechanism apparatus, comprising; a motor whose stopping distance is to be controlled from a known velocity to zero velocity in accordance with a preselected velocity-versus-distance profile, means establishing said preselected velocity-versus-distance profile as a control reference, motor distance measuring means providing an output at a plurality of discrete distance checkpoints, motor velocity measuring means, and control means for said motor receiving as inputs said first named means and said velocity measuring means, and being controlled by said distance measuring means to compare said motor velocity to said control reference in accordance with the known distance parameter and to variably control said motor at each distance checkpoint in a manner devised to achieve the profile velocity at a subsequent distance checkpoint.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1976-06-04	1976-12-04	1977-06-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1980-06-04	1980-12-04	1981-06-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1984-06-04	1984-12-04	1985-06-05	$7700.00	Window Closed / Lapsed

Servomechanism stop control

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