Digital position measurement and control system

Claim 2

A digital position measurement system adapted to be operatively associated with first and second members relatively movable along a given path, the measurement system including in combination: actual address means having a plurality of digital address indicia disposed along said path indicative of actual relative locations of said members, said path being divided into a plurality of predetermined dimensions, position reference indicia precisely indicative of given relative location reference points on said path in a given spatial relation to locations of said members indicated by said digital address indicia, respectively, said actual address means supplying electrical signals indicative of said digital address indicia and said position reference indicia, incremental displacement measuring means operatively aSsociated with said members for indicating incremental displacements and direction thereof between said members independent of said actual address means, digital delta-address means for storing an initial delta-address indicative of a necessary relative displacement of said members to reach a desired one of said locations and being jointly responsive to said initial delta-address and to said indication of incremental displacement to supply a present delta address indicative of the difference therebetween and further responsive to said position reference indicia to preset a selected portion of said present delta address for calibrating said present delta address to a numerical value indicative of an integral number of said predetermined dimensions along said given path.

Claim 3

The measurement system of claim 1, further including control means operatively associated with said actual address means for receiving said signals indicative of said digital address indicia and being selectively responsive thereto to generate a set of digital initial delta-address signals, and means for selectively transferring said digital initial delta-address signals to said digital delta-address means.

Claim 4

The measurement system of claim 2, wherein said digital address indicia are disposed in a plurality of strips, each strip having indicia of a plurality of contiguous locations along said given path, said strips being spaced apart along said given path by varied spacing dimensions, said spacings capable of being other than an integral number of said predetermined dimensions, spacing means for supplying spacing digital signals indicative of said spacings as an integral number of said predetermined dimensions, and said control means being responsive to said spacing digital signals to effect successive delta-address indications by said digital delta-address means in accordance with said spacing digital signals in addition to said indications of said incremental displacement means altering said initial delta-address such that relative motion of said members traversing some of said spacings is indicated as an integral number of said predetermined dimensions.

Claim 5

The measurement system of claim 3, wherein each said strip has a plurality of rows of said digital indicia, indicia in each row arranged in groups in accordance with said locations and being respectively indicative of the respective location, said digital indicia being directed into groups of strip-identifying indicia and location-identifying indicia, said strip-identifying indicia being disposed intermediate each adjacent location in said strip plus at both extremities of said strip along said given path with said location indicia being interposed between said strip indicia in each of said strips, each strip further including control indicia associated with said digital indicia for indicating whether the address indicated thereby is a strip or location address.

Claim 6

The measurement system of claim 4, wherein said control indicia is narrower along said given path than the respective digital indicia, said actual address means being nonresponsive to said digital indicia intermediate said control indicia.

Claim 7

The measurement system of claim 5, wherein said control indicia associated with said strip address indicating digital indicia is said position reference indicia and has a width along said given path a predetermined number of incremental displacements, said actual address means receiving said indications of incremental displacements and being jointly responsive to said position reference indicia and said indication of incremental displacements to generate said electrical signal indicative of said position reference indicia during one of said incremental displacements occurring in a predetermined relation to said position reference indicia.

Claim 8

The measurement system of claim 6, wherein said control means includes a programmable digital computer having a memory, said spacing means constituting stored signals in saiD memory as a table of spacing lengths and addresses thereof, said control means supplying said spacing digital signals to said digital delta-address means as a part of said initial delta-address such that said spacings are measured in the same manner as said strips.

Claim 9

Digital position indicating means for a pair of relatively movable first and second members wherein the second member has means for sensing indicia, the indicating means including the combination: a plurality of groups of spatial-address indicia stationarily disposed in a predetermined relation with respect to said first member, each group having a plurality of location indicia, each location having a predetermined dimension along a given direction of relative movement, said groups being disposed along said given direction of relative movement, said groups being disposed along said given direction of relative movement between said members in a spaced-apart relationship capable of having spacings between adjacent ones of said groups varied in a nonintegral relationship to said predetermined dimension, each group having a plurality of sets of identical unique group-identifying indicia disposed respectively on both sides of each said location indicia along said direction of relative motion.

Claim 10

Digital position indicating means for a pair of relatively movable first and second members wherein the second member has means for sensing indicia, the indicating means including the combination: a plurality of groups of spatial-address indicia stationarily disposed in a predetermined relation with respect to said first member, each group having a plurality of location indicia, each location having a predetermined dimension along a given direction of relative movement, said groups being disposed along said given direction of relative movement, said groups being disposed along said given direction of relative movement between said members in a spaced-apart relationship capable of having spacings between adjacent ones of said groups varied in a nonintegral relationship to said predetermined dimension, each group having a plurality of sets of identical unique group-identifying indicia disposed respectively on both sides of each said location indicia along said direction of relative motion.

Claim 11

The indicating means of claim 8, wherein each said spatial-address indicia further includes position reference indicia associated with each said group indicia for identifying same as group indicia and further having a precise spatial relationship to the respective location for enabling a precise recalibration regarding relative movements of said members.

Claim 12

A linear positioning system of the numerical type for accurately positioning first and second relatively movable members over an extended range of incremental relative movements along a given path, each relative movement being expressible numerically as a given number of discrete steps, each discrete step including a predetermined number of incremental displacements, the improvement including in combination: a plurality of work locations along said given path at which predetermined functions may be performed, each location having a predetermined positional relation to respective given ones of said discrete steps, some of said discrete steps not having said positional relation to said locations, said members having to traverse spacings between adjacent ones of said locations being other than an integral number of said discrete steps, incremental displacement measurement means sensing and indicating relative displacements between said members, actual address means independent of said measurement means indicating actual relative positions of said members at each said location and indicating a precise relative position of said members with respect to said locations irrespective of said actual address, digital control and motive means responsive to said actual relative location indication to generate an initial digital delta address indicative of relative displacements of said members to desired locations and expressed as an integral number of said discrete steps and being further responsive to said incremental displacement measurement means to generate a present digital address from said initial digital delta address and including measurements of said nonintegral spacings, and being further responsive to said precise position indication when said present digital delta address indicates a nonintegral number of discrete steps at any one of said precise position indications to adjust said present delta address to represent an integral number of said discrete steps.

Claim 13

A linear positioning system of the numerical type for accurately positioning first and second relatively movable members over an extended range of incremental relative movements along a given path, each relative movement being expressible numerically as a given number of discrete steps, each discrete step including a predetermined number of incremental displacements, the improvement including in combination: a plurality of work locations along said given path at which predetermined functions may be performed, each location having a predetermined positional relation to respective given ones of said discrete steps, some of said discrete steps not having said positional relation to said locations, said members having to traverse spacings between adjacent ones of said locations being other than an integral number of said discrete steps, incremental displacement measurement means sensing and indicating relative displacements between said members, actual address means independent of said measurement means indicating actual relative positions of said members at each said location and indicating a precise relative position of said members with respect to said locations irrespective of said actual address, digital control and motive means responsive to said actual relative location indication to generate an initial digital delta address indicative of relative displacements of said members to desired locations and expressed as an integral number of said discrete steps and being further responsive to said incremental displacement measurement means to generate a present digital address from said initial digital delta address and including measurements of said nonintegral spacings, and being further responsive to said precise position indication when said present digital delta address indicates a nonintegral number of discrete steps at any one of said precise position indications to adjust said present delta address to represent an integral number of said discrete steps.

Claim 14

The positioning system of claim 10, wherein said control and motive means includes: motor means for effecting relative movements of said members, up/down counter means for receiving said initial delta address and containing said present delta addresses as numerical contents, being responsive to said incremental displacement measurement means indications to alter The numerical contents thereof in accordance with said incremental indications and having a reference signal state indicative of a reference numerical content, and servocontrol means operatively controlling said motor means in response to the numerical contents of said up/down counter means to cause a relative movement whenever said up/down counter means has a numerical content other than said reference numerical content and further responsive to said reference signal state to actuate said motor means to positively hold said members against relative movements.

Claim 15

The positioning system of claim 11, wherein said control and motive means further includes program means storing a list of said spacings and an equivalent number of said discrete steps representative of lengths of said spacings irrespective of said nonintegral number of discrete steps therein, said equivalent number of discrete steps ignoring nonintegral portions less than one-half of said discrete steps and counting as a complete discrete step nonintegral portions greater than one-half of said discrete steps, and said program means being operative to compare said list with said actual address indication and a desired address indication for determining the number of discrete steps in spacings between locations corresponding to said actual address and said desired address and then being operative to generate an initial delta address in accordance therewith.

Claim 16

The positioning system of claim 12, wherein said actual address means includes a plurality of address strips stationarily associated with said first member and disposed in spaced-apart relationship along said given path, each address strip being positioned on said first member independent of positions therein of any other address strip, each said address strip including a plurality of location actual address indicia, each such location actual address indicia including two sets of identical strip indicia spaced apart along said given path at the extremities of each such location along said given path with a location address with respect to such strip disposed intermediate said strip indicia, position reference indicia having a predetermined and precise relationship to such location disposed at each said extremity along said given path and further identifying said strip indicia, and said actual address means further including, indicia sensing means on said second member movable to an operative position with any one of said address strips and responsive thereto to indicate actual address and precise position reference.

Claim 17

The positioning system of claim 13, wherein each said discrete step is identical in length, and further including: up/down counter means in said control and motive means having a lower portion of a modulus equal to said predetermined number of incremental displacements and an upper portion for containing a delta address expressed as an integral number of discrete steps, said upper portion receiving said initial delta address and being responsive to said lower portion counting past a predetermined count to alter its numerical contents in accordance therewith, and said lower portion being responsive to said position reference signal to assume a signal state representative of one-half said predetermined number of incremental displacements from a reference signal state indicative of a center of said discrete steps, said up/down counter means being responsive to said relative displacement indications to alter its numerical contents in accordance therewith, and said control and motive means being responsive to numerical contents in said up/down counter means to effect relative movement of said members in a direction and extent to alter the numerical contents of both said portions to a reference state.

Claim 18

A digital positioning system for positioning first and second relatively movable members over an extendible range along a given path of relative movements while maintaining location accuracy, a pluraLity of first digital indicia on said first member indicative of a plurality of discrete relative locations spaced along said path, each having a given dimension, spacings between some of said first indicia being varied from said given dimensions in a nonintegral manner, a like plurality of second indicia on said first member precisely located with respect to said discrete locations, digital displacement measuring means responsive to relative movements of said members to supply count signals indicative of incremental displacements and direction thereof along said given path, sensing means on said second member responsive to said first and second indicia to supply actual address and position reference signals respectively, indicative of actual relative positions of said members, program means responsive to said actual address signals to generate an initial digital delta address for a desired actual address to which said members are to relatively move and including table means indicating effect of said spacings on said initial delta address, said initial address including said effect of said spacings, up/down counter means having upper and lower portions, said upper portion receiving said initial delta address from said program means, said lower portion having a modulus numerically indicative of said given dimension, each portion capable of having a reference signal state, said up/down counter means being responsive to said count signals to alter the contents thereof from said initial delta address for generating a present delta address, all counting proceeding from said lower portion to said upper portion, motor means operatively associated with said members and responsive to said up/down counter means containing a delta address to cause a relative displacement of said members effective to alter the contents of said up/down counter means toward said reference signal states and further responsive to said up/down counter means being in said reference states to hold said members from further relative displacements, and said lower portion being responsive to said position reference signal to assume a signal state incrementally representative of said second indicia location thereby compensating for nonintegral variations of said spacings from said given dimension to enable an accurate positioning based upon a delta address representing an integral number of said discrete addresses.

Claim 19

A digital positioning system for positioning first and second relatively movable members over an extendible range along a given path of relative movements while maintaining location accuracy, a pluraLity of first digital indicia on said first member indicative of a plurality of discrete relative locations spaced along said path, each having a given dimension, spacings between some of said first indicia being varied from said given dimensions in a nonintegral manner, a like plurality of second indicia on said first member precisely located with respect to said discrete locations, digital displacement measuring means responsive to relative movements of said members to supply count signals indicative of incremental displacements and direction thereof along said given path, sensing means on said second member responsive to said first and second indicia to supply actual address and position reference signals respectively, indicative of actual relative positions of said members, program means responsive to said actual address signals to generate an initial digital delta address for a desired actual address to which said members are to relatively move and including table means indicating effect of said spacings on said initial delta address, said initial address including said effect of said spacings, up/down counter means having upper and lower portions, said upper portion receiving said initial delta address from said program means, said lower portion having a modulus numerically indicative of said given dimension, each portion capable of having a reference signal state, said up/down counter means being responsive to said count signals to alter the contents thereof from said initial delta address for generating a present delta address, all counting proceeding from said lower portion to said upper portion, motor means operatively associated with said members and responsive to said up/down counter means containing a delta address to cause a relative displacement of said members effective to alter the contents of said up/down counter means toward said reference signal states and further responsive to said up/down counter means being in said reference states to hold said members from further relative displacements, and said lower portion being responsive to said position reference signal to assume a signal state incrementally representative of said second indicia location thereby compensating for nonintegral variations of said spacings from said given dimension to enable an accurate positioning based upon a delta address representing an integral number of said discrete addresses.

Claim 20

A linear digital position measurement system for use with first and second relatively movable members, motor means including motor control means operating associated with said members for effecting relative displacements between said members, the system including in combination: sets of spaced-apart digital indicia stationarily associated with said first member along a direction of relative movement for indicating actual relative discrete locations between said members, each said location having a predetermined dimension along said direction, spacings between some of said indicia being different from other spacings between other indicia, said spacings capable of having nonintegral dimensional relationships with respect to said predetermined dimensions, each said set of digital indicia including precise reference indicia indicative of a given precise relative position of said members with respect to the respective said relative locations indicated by said digital indicia; sensing means on said second member capable of sensing said indicia and operative to supply signals indicative thereof including actual address signals and a precise position reference signal; incremental displacement measuring means disposed in cooperating relationship with said members for measuring relative displacements therebetween irrespective of said discrete locations and supplying count signals indicative of predetermined incremental displacements and a direction signal indicative of relative displacement; programmable control means for receiving said actual address signals and operative to supply initial delta-address digital signals indicative of the number of said locations and spacings to be traversed by said members to reach a desired discrete location; up/down counter means having upper and lower portions, said upper portion receiving said initial delta-address digital signals, said lower portion receiving said count signals and being responsive thereto to count same for indicating incremental displacements and responsive to said direction signal to effect a count up or a count down for indicating direction of such relative incremental displacements and indicating to said upper portion when said second member passes one of said locations, said upper portion being responsive to such latter indication to alter said initial delta-address in accordance therewith; said motor control means being responsive to said up/down counter means containing a delta-address to cause said motor means to effect a relative displacement in a direction to alter the signal contents of said up/down counter means toward a first reference count in each of said portions, said effected displacement being representable by the numerical contents of said upper portion; said lower portion being responsive to said position reference signal to assume a second reference count irrespective of the contents of said upper portion and such that when the numerical content of said upper portion is said first reference count said motor means effects a relative displacement in accordance with said second reference signal state of said lower portion with respect to said desired location and, further, when said upper portion has a numerical content other than said first reference count, to adjust such relative movements to an integral number of said discrete locations whereby said randomness of spacings or any incremental displacement measurement error is erased.

Claim 21

A linear digital position measurement system for use with first and second relatively movable members, motor means including motor control means operating associated with said members for effecting relative displacements between said members, the system including in combination: sets of spaced-apart digital indicia stationarily associated with said first member along a direction of relative movement for indicating actual relative discrete locations between said members, each said location having a predetermined dimension along said direction, spacings between some of said indicia being different from other spacings between other indicia, said spacings capable of having nonintegral dimensional relationships with respect to said predetermined dimensions, each said set of digital indicia including precise reference indicia indicative of a given precise relative position of said members with respect to the respective said relative locations indicated by said digital indicia; sensing means on said second member capable of sensing said indicia and operative to supply signals indicative thereof including actual address signals and a precise position reference signal; incremental displacement measuring means disposed in cooperating relationship with said members for measuring relative displacements therebetween irrespective of said discrete locations and supplying count signals indicative of predetermined incremental displacements and a direction signal indicative of relative displacement; programmable control means for receiving said actual address signals and operative to supply initial delta-address digital signals indicative of the number of said locations and spacings to be traversed by said members to reach a desired discrete location; up/down counter means having upper and lower portions, said upper portion receiving said initial delta-address digital signals, said lower portion receiving said count signals and being responsive thereto to count same for indicating incremental displacements and responsive to said direction signal to effect a count up or a count down for indicating direction of such relative incremental displacements and indicating to said upper portion when said second member passes one of said locations, said upper portion being responsive to such latter indication to alter said initial delta-address in accordance therewith; said motor control means being responsive to said up/down counter means containing a delta-address to cause said motor means to effect a relative displacement in a direction to alter the signal contents of said up/down counter means toward a first reference count in each of said portions, said effected displacement being representable by the numerical contents of said upper portion; said lower portion being responsive to said position reference signal to assume a second reference count irrespective of the contents of said upper portion and such that when the numerical content of said upper portion is said first reference count said motor means effects a relative displacement in accordance with said second reference signal state of said lower portion with respect to said desired location and, further, when said upper portion has a numerical content other than said first reference count, to adjust such relative movements to an integral number of said discrete locations whereby said randomness of spacings or any incremental displacement measurement error is erased.

Claim 24

The method of claim 17, further including the steps of independently ascertaining the relative location of said members when said altered delta address indicates a desired location has been reached and establishing said desired location as a new base of positioning reference for a new digital initial delta address to thereby cause a new movement controlled solely by said new digital initial delta address.