Adaptive motor acceleration

Claim 2

Motor speed-control servomechanism, comprising: a variable speed motor capable of accepting variable energization, a controllable network connected to said motor and operable to control the energization of said motor, sample data distance measuring means connected to said motor and operable to provide a discrete output for each unit of motor movement, period measuring means controlled by said distance measuring means and operable to measure the time interval required for the motor to move a unit distance, addressable memory means having a plurality of unique memory locations each of which is accessible by a different address, said memory means being constructed and arranged to define an acceleration and/or decelEration profile which the motor is to follow as the motor accelerates and/or decelerates from different unique motor positions, between time adjacent discrete outputs of said sample data distance measuring means, to a different speed condition, an address selection means controlled by said distance measuring means and operable to address unique memory locations in accordance with the relationship of said unique motor position and said time adjacent discrete outputs of said distance measuring means, said unique memory locations adaptively defining points on said acceleration and/or deceleration profile in accordance with said unique motor position, and comparison means connected to compare the output of said period measuring means to the output of said memory means and operable to control said controllable network in accordance with the comparison.

Claim 3

A motor control servomechanism as defined in claim 1 wherein said distance measuring means is constructed and arranged to provide an output pulse for equal incremental units of motor motion, and wherein said address selection means is controlled in accordance with the relationship of said unique motor position to a predetermined output pulse which occurs as said motor accelerates and/or decelerates from said unique position.

Claim 4

A motor control servomechanism as defined in claim 2 wherein said address selection means includes counter means, a clock, and means enabling said counter means to begin counting said clock upon speed change of said motor from said unique position, said predetermined output pulse being effective to enable said counter means to address said memory means upon the occurrence of said predetermined output pulse.

Claim 5

A motor control servomechanism as defined in claim 3 wherein said counter means is operable to select a unique period measure from said memory means which is indicative of the desired time interval to a subsequent predetermined output pulse, and wherein said comparison means is effective to compare this desired time interval to the actual time interval upon the occurrence of said subsequent predetermined output pulse.

Claim 6

In a sampled-data motor speed-control servomechanism wherein the motor drives a digital tachometer and is variably energized during acceleration and/or deceleration to follow a predefined acceleration and/or deceleration profile, an improved means for defining said profile, comprising: addressable memory means containing a plurality of addressable locations which define said profile, address selection network means operable to uniquely address said memory means locations, means connecting said digital tachometer in controlling relation to said address selection network means to control the same in a manner to adaptively select memory locations which are uniquely related to the unique motor position at which the motor begins its acceleration and/or deceleration as this position is distance related to the next subsequent pulse derived from said digital tachometer, and motor energizing means controlled by said digital tachometer and by said memory means and operable to variably energize said motor during acceleration and/or deceleration, causing the motor''s acceleration and/or deceleration profile to follow the profile defined by the data stored in said memory means.

Claim 7

In a sampled-data motor speed-control servomechanism wherein the motor drives a digital tachometer and is variably energized during acceleration and/or deceleration to follow a predefined acceleration and/or deceleration profile, an improved means for defining said profile, comprising: addressable memory means containing a plurality of addressable locations which define said profile, address selection network means operable to uniquely address said memory means locations, means connecting said digital tachometer in controlling relation to said address selection network means to control the same in a manner to adaptively select memory locations which are uniquely related to the unique motor position at which the motor begins its acceleration and/or deceleration as this position is distance related to the next subsequent pulse derived from said digital tachometer, and motor energizing means controlled by said digital tachometer and by said memory means and operable to variably energize said motor during acceleration and/or deceleration, causing the motor''s acceleration and/or deceleration profile to follow the profile defined by the data stored in said memory means.

Claim 8

A sampled-data motor control servomechanism as defined in claim 5 wherein each location of said memory means contains data defining a unique time period which should exist between a tachometer output pulse which has just occurred and a preselected subsequent tachometer output pulse, and wherein said motor energizing means includes time period measuring means including a time reference controlled by said tachometer, comparison means operable to compare the data selected from said memory means to the measured time period to said subsequent tachometer output pulse, and means controlled by said comparison means for variably energizing said motor.

Claim 9

In a mAgnetic tape unit wherein a length of tape is adapted to be maintained in continuous engagement with a single rotatable capstan, such that capstan movement is directly translated into tape movement, and wherein the tape is adapted to contain a format of data blocks separated by interblock gaps, said capstan having a rest position which places a magnetic head in said gap and being capable of decelerating from a steady-state target speed to said rest position and subsequently accelerating to said steady-state target speed such that said head enters and traverses an adjacent data block at said target speed, the improvement comprising: an electric motor directly connected to said capstan, a digital tachometer connected to said motor, said tachometer providing an output pulse for equal units of motor rotation, memory means having a plurality of addressable locations which define a desired motor deceleration and acceleration profile from said target speed to said rest position and from said rest position to said target speed, means providing a capstan stop command and a capstan start command, address selection means controlled by said capstan stop command and said capstan start command and by said first tachometer deceleration output pulse and said first tachometer acceleration output pulse, and the succeeding output pulses which occur during deceleration and acceleration, and operable to address unique locations of said memory means in accordance with the distance said motor moves from the occurrence of a capstan command to said tachometer output pulses, measuring means controlled by said tachometer and operable to measure the motor''s actual deceleration profile from said first deceleration pulse to said rest position, and additionally operable to measure the motor''s actual acceleration profile from said first acceleration output pulse to said target speed, and comparison means operable to variably energize motor in accordance with a comparison of the output of said measuring means to said memory means.

Claim 10

In a mAgnetic tape unit wherein a length of tape is adapted to be maintained in continuous engagement with a single rotatable capstan, such that capstan movement is directly translated into tape movement, and wherein the tape is adapted to contain a format of data blocks separated by interblock gaps, said capstan having a rest position which places a magnetic head in said gap and being capable of decelerating from a steady-state target speed to said rest position and subsequently accelerating to said steady-state target speed such that said head enters and traverses an adjacent data block at said target speed, the improvement comprising: an electric motor directly connected to said capstan, a digital tachometer connected to said motor, said tachometer providing an output pulse for equal units of motor rotation, memory means having a plurality of addressable locations which define a desired motor deceleration and acceleration profile from said target speed to said rest position and from said rest position to said target speed, means providing a capstan stop command and a capstan start command, address selection means controlled by said capstan stop command and said capstan start command and by said first tachometer deceleration output pulse and said first tachometer acceleration output pulse, and the succeeding output pulses which occur during deceleration and acceleration, and operable to address unique locations of said memory means in accordance with the distance said motor moves from the occurrence of a capstan command to said tachometer output pulses, measuring means controlled by said tachometer and operable to measure the motor''s actual deceleration profile from said first deceleration pulse to said rest position, and additionally operable to measure the motor''s actual acceleration profile from said first acceleration output pulse to said target speed, and comparison means operable to variably energize motor in accordance with a comparison of the output of said measuring means to said memory means.

Claim 11

A magnetic tape unit as defined in claim 7 wherein the first deceleration output pulse and the first acceleration output pulse, and all subsequent deceleration and acceleration output pulses, are operable to select data from said memory means indicative of the desired time interval to the subsequent output pulse, wherein said measuring means is operable to measure the actual time interval between each tachometer output pulse and a subsequent output pulse as a measure of the motor''s actual deceleration and acceleration profile, and wherein said comparison means is operable to variably energize said motor upon the occurrence of said second tachometer output pulses.

Claim 12

A magnetic tape unit as defined in claim 10 including means controlled by said capstan start command to provide preselected energization of said motor, which preselected energization is maintained until the occurrence of the second acceleration output pulse.

Claim 13

A magnetic tape unit as defined in claim 11 wherein said address selection means includes time interval measuring means initially operable to select data from said memory means in accordance with the time interval between the occurrence of said capstan start command and said first acceleration output pulse, and operable thereafter to select data in accordance with the time interval between adjacent acceleration output pulses, said data being indicative of the desired time interval to a subsequent tachometer pulse in accordance with the desired acceleration profile.

Claim 14

A magnetic tape unit as defined in claim 10 wherein said memory means locations additionally define said target speed by containing data indicative of equal time intervals between adjacent tachometer output pulses.

Claim 15

A magnetic tape unit as defined in claim 9 including means controlled by said capstan stop command to provide preselected plugging energization of said motor, which preselected energization is maintained until occurrEnce of the second deceleration output pulse.

Claim 16

A magnetic tape unit as defined in claim 12 wherein said address selection means includes time interval measuring means initially operable to select data from said memory means in accordance with the time interval between the occurrence of said capstan stop command and said first deceleration output pulse, and operable thereafter to select data in accordance with the time interval between adjacent deceleration output pulses, said data being indicative of the desired time interval to a subsequent tachometer pulse in accordance with the desired deceleration profile.

Claim 17

A magnetic tape unit as defined in claim 13 wherein a means responsive to a given motor speed lower than said target speed is effective to interrupt further plugging energization of said motor.

Claim 18

A sample-data motor acceleration servo for use in accelerating a motor from rest to a target speed comprising: a distance measuring transducer connected to said motor and providing an output pulse for each distance unit of motor movement subsequent to the first output pulse, said first output pulse occurring at variable distances less than said unit distance, in accordance with the rest position of said motor, a period counter, a high frequency clock connected to increment said period counter from an initial state, said frequency being higher than the frequency of said transducer output pulses when said motor is running at said target speed, means connecting said transducer in controlling relation to said period counter to initialize said period counter upon the occurrence of each said transducer output pulses such that the content of said period counter prior to initializing is indicative of the time interval between adjacent transducer output pulses, memory means containing a plurality of storage locations, each one of which contains a unique number indicative of the desired contents of said period counter prior to initialization during different portions of the motor''s acceleration profile from rest to said target speed, address selection means controlled both by the occurrence of a motor start command and by said transducer output pulses, initially operable to address a memory location whose number decreases as the time interval for the motor to move from its variable rest position to the occurrence of said first transducer output pulse increases, and thereafter operable to address a memory location whose number additionally decreases in accordance with the additional time for the motor to move to the subsequent transducer output pulses, comparison means operable to compare the memory location number which was selected upon the occurrence of a transducer output pulse to the content of said period counter which exists upon the occurrence of the subsequent transducer output pulse, and means controlled by said comparison means and operable to energize said motor in accordance with said comparison, said energization being operable to cause said motor to achieve said acceleration profile.

Claim 19

A sample-data motor acceleration servo for use in accelerating a motor from rest to a target speed comprising: a distance measuring transducer connected to said motor and providing an output pulse for each distance unit of motor movement subsequent to the first output pulse, said first output pulse occurring at variable distances less than said unit distance, in accordance with the rest position of said motor, a period counter, a high frequency clock connected to increment said period counter from an initial state, said frequency being higher than the frequency of said transducer output pulses when said motor is running at said target speed, means connecting said transducer in controlling relation to said period counter to initialize said period counter upon the occurrence of each said transducer output pulses such that the content of said period counter prior to initializing is indicative of the time interval between adjacent transducer output pulses, memory means containing a plurality of storage locations, each one of which contains a unique number indicative of the desired contents of said period counter prior to initialization during different portions of the motor''s acceleration profile from rest to said target speed, address selection means controlled both by the occurrence of a motor start command and by said transducer output pulses, initially operable to address a memory location whose number decreases as the time interval for the motor to move from its variable rest position to the occurrence of said first transducer output pulse increases, and thereafter operable to address a memory location whose number additionally decreases in accordance with the additional time for the motor to move to the subsequent transducer output pulses, comparison means operable to compare the memory location number which was selected upon the occurrence of a transducer output pulse to the content of said period counter which exists upon the occurrence of the subsequent transducer output pulse, and means controlled by said comparison means and operable to energize said motor in accordance with said comparison, said energization being operable to cause said motor to achieve said acceleration profile.

Claim 20

A sample-data motor acceleration servo as defined in claim 15 wherein said address selection means includes an address counter which is driven at a constant frequency from an initial setting, said address counter drive being initiated by the occurrence of said motor start command, and said address counter being interrogated by said transducer output pulses, with the then-existing contents of said address counter being used to effect selection of a number from said memory means.

Claim 21

A sampled-data motor deceleration servo for use in decelerating a motor from a target speed to rest, comprising: a distance measuring transducer connected to said motor and providing an output pulse for each distance unit of motor movement subsequent to the first output pulse to occur after a motor stop command is received, said first output pulse occurring at variable distances less than said unit distance, in accordance with the uniQue motor position at which a stop command is received, a period counter, a high frequency clock connected to increment said period counter from an initial state, said frequency being higher than the frequency of said transducer output pulses when said motor is running at said target speed, means connecting said transducer in controlling relation to said period counter to initialize said period counter upon the occurrence of each of said transducer output pulses such that the content of said period counter prior to initializing is indicative of the time interval between adjacent tachometer output pulses, memory means containing a plurality of storage locations, each one of which contains a unique number indicative of the desired contents of said period counter prior to initialization during different portions of the motor''s deceleration profile from said target speed to rest, address selection means controlled both by the occurrence of said motor stop command and by said transducer output pulses, initially operable to address a memory location whose number increases as the time interval for the motor to move from said unique position to the occurrence of said first transducer output pulse increases, and thereafter operable to address a memory location whose number additionally increases in accordance with the additional time for the motor to move to the subsequent transducer output pulses, comparison means operable to compare the memory location number which was selected upon the occurrence of a transducer output pulse to the contents of said period counter which exists upon the occurrence of the subsequent transducer output pulse, and means controlled by said comparison means and operable to energize said motor in accordance with said comparison, said energization being operable to cause said motor to achieve said deceleration profile.

Claim 22

A sampled-data motor deceleration servo for use in decelerating a motor from a target speed to rest, comprising: a distance measuring transducer connected to said motor and providing an output pulse for each distance unit of motor movement subsequent to the first output pulse to occur after a motor stop command is received, said first output pulse occurring at variable distances less than said unit distance, in accordance with the uniQue motor position at which a stop command is received, a period counter, a high frequency clock connected to increment said period counter from an initial state, said frequency being higher than the frequency of said transducer output pulses when said motor is running at said target speed, means connecting said transducer in controlling relation to said period counter to initialize said period counter upon the occurrence of each of said transducer output pulses such that the content of said period counter prior to initializing is indicative of the time interval between adjacent tachometer output pulses, memory means containing a plurality of storage locations, each one of which contains a unique number indicative of the desired contents of said period counter prior to initialization during different portions of the motor''s deceleration profile from said target speed to rest, address selection means controlled both by the occurrence of said motor stop command and by said transducer output pulses, initially operable to address a memory location whose number increases as the time interval for the motor to move from said unique position to the occurrence of said first transducer output pulse increases, and thereafter operable to address a memory location whose number additionally increases in accordance with the additional time for the motor to move to the subsequent transducer output pulses, comparison means operable to compare the memory location number which was selected upon the occurrence of a transducer output pulse to the contents of said period counter which exists upon the occurrence of the subsequent transducer output pulse, and means controlled by said comparison means and operable to energize said motor in accordance with said comparison, said energization being operable to cause said motor to achieve said deceleration profile.

Claim 23

A sampled-data motor deceleration servo as defined in claim 17 wherein said address selection means includes an address counter which is driven at a constant frequency from an initial setting, said address counter drive being initiated by the occurrence of said motor stop command, and said address counter being interrogated by said transducer output pulses, with the then-existing contents of said address counter being used to effect selection of a number from said memory means.

Claim 24

In a closed-loop sampled-data motor speed servo which receives a motor speed feedback signal from a digital transducer whose pulse frequency is proportional to the motor''s speed, an improved apparatus for accelerating and/or decelerating the motor between a given speed and a variable rest position, comprising: storage means containing a plurality of predefined numbers indicative of desired transducer pulse time intervals commensurate with said motor accelerating and/or decelerating from one of a range of unique variable motor positions defined by the two transducer pulses which bracket the unique position from which acceleration and/or deceleration begins, an address counter, means providing motor start and stop commands, means controlled by said motor start and stop commands for advancing said address counter as said motor begins its acceleration and/or deceleration from said unique position, means controlled by a given transducer pulse which occurs after beginning of acceleration and/or deceleration to interrogate said address counter and to select a unique number from said storage means in accordance with said address, said unique number representing the desired time interval to a subsequent transducer pulse, motor speed measuring means controlled by said digital transducer and operable to measure the speed of said motor as a function of the time interval between transducer pulses, and motor energizing means controlled by said speed measuring means and said unique number selected from said storage means and operable to variably energize said motor in a manner to cause the time inTerval between transducer pulses to be as defined by said unique number.

Claim 25

In a closed-loop sampled-data motor speed servo which receives a motor speed feedback signal from a digital transducer whose pulse frequency is proportional to the motor''s speed, an improved apparatus for accelerating and/or decelerating the motor between a given speed and a variable rest position, comprising: storage means containing a plurality of predefined numbers indicative of desired transducer pulse time intervals commensurate with said motor accelerating and/or decelerating from one of a range of unique variable motor positions defined by the two transducer pulses which bracket the unique position from which acceleration and/or deceleration begins, an address counter, means providing motor start and stop commands, means controlled by said motor start and stop commands for advancing said address counter as said motor begins its acceleration and/or deceleration from said unique position, means controlled by a given transducer pulse which occurs after beginning of acceleration and/or deceleration to interrogate said address counter and to select a unique number from said storage means in accordance with said address, said unique number representing the desired time interval to a subsequent transducer pulse, motor speed measuring means controlled by said digital transducer and operable to measure the speed of said motor as a function of the time interval between transducer pulses, and motor energizing means controlled by said speed measuring means and said unique number selected from said storage means and operable to variably energize said motor in a manner to cause the time inTerval between transducer pulses to be as defined by said unique number.

Claim 26

The motor speed servo defined in claim 19 wherein said motor speed measuring means includes, a speed counter, a high frequency clock connected to increment said speed counter, means controlled by said digital transducer and effective to initialize said counter on the occurrence of said given transducer pulse, and wherein said motor energizing means includes, comparing means effective to compare said unique number to the contents of said speed counter upon the occurrence of said subsequent transducer pulse.

Claim 27

The motor speed servo defined in claim 20, wherein said motor energizing means includes, means controlled by said comparing means and operable to servo control motor acceleration and/or deceleration for the time interval between said subsequent transducer pulse and a further subsequent transducer pulse in accordance with the error between said unique number and the contents of said speed counter at the occurrence of said subsequent transducer pulse.