Feedrate control system for numerical control apparatus

Claim 2

Apparatus for generating axis command pulses to be supplied to at least two drives having mutually orthogonal axes of motion to produce a reSultant movement of a member in accordance with a predetermined path and velocity programmed in a program store, the program store including axes command data representing the programmed axes distances and feedrate command data representing the programmed vector velocities, the apparatus comprising: a path generator system operative to generate, in response to the program store axes command data, a train of axes command pulses for each axis, to be supplied to the respective drives, and a velocity control system operative to compare the program store feedrate command data with the vector velocity that is the resultant of the generated axes command pulses and to produce feed pulses controlling the path generator system such that said resultant vector velocity will correspond to said program store feedrate command data; said velocity control system comprising: means for converting the feedrate command data to a train of feedrate command pulses; a feedrate command register accumulating said feedrate command pulses; an axis command register for each axis, accumulating the command pulses of its respective axis; an error register; means effective upon the occurrence of each axis command pulse for summing, according to one sign, the count of the respective axis register into the error register; means effective upon the occurrence of each feedrate command pulse for summing, according to the opposite sign, the count of the feedrate command register into the error register; and means enabling the path generator system to generate axis command pulses only when the count in the error register is of said opposite sign.

Claim 3

Apparatus as defined in claim 1, wherein: the means effective upon the occurrence of each axis command pulse adds the count of the respective axis register into the error register; the means effective upon the occurrence of each feedrate command pulse subtracts the count of the feedrate command register from the error register; and said enabling means enables the path generator system to generate axis command pulses only when the error register is negative.

Claim 4

Apparatus as defined in claim 1, further including means for clearing all said registers when the feedrate command register reaches the limit of its capacity.

Claim 5

Apparatus as defined in claim 1, further including means for clearing all said registers upon receiving a new motion command from the program store.

Claim 6

Apparatus according to claim 1, wherein the means for converting the feedrate command data to a train of feedrate command pulses comprises a pulse generator and a multiplier receiving the pulses produced by the pulse generator at one of its inputs, and the feedrate command data at another of its inputs.

Claim 7

Apparatus as defined in claim 5, wherein said pulse generator is of variable frequency, and said apparatus further includes an operator feedrate over-ride controlling the frequency of the pulse generator.

Claim 8

Apparatus as defined in claim 6, further including mode controlling means enabling the apparatus to operate according to the distance-per-minute mode or the distance-per-revolution mode; said apparatus further including, to enable its operation in the latter mode, a counter receiving the output pulses from said multiplier, means for resetting the counter to zero at a fixed sample interval, a second multiplier, means for applying the count of said latter counter to one input of said second multiplier, and a spindle-driven digital tachometer supplying pulses to the other input of said second multiplier.

Claim 9

Numerical control equipment for moving a member in accordance with a predetermined path, comprising: apparatus for generating axis command pulses as defined in claim 1, means for introducing path and feedrate data into said apparatus for generating said axis command pulses; and at least two drives having mutually orthogonal axes of motion controlled by the generated axes command pulses to produce a resultant movement of the member driven by the drives in accordance with said path and feEdrate data.

Claim 10

Apparatus for generating axis command pulses to be supplied to at least two drives having mutually orthogonal axes of motion to produce a resultant movement of a member in accordance with a predetermined path, comprising, a path generator system operative to generate, in response to axes command data introduced into the apparatus, a train of axes command pulses for each axis to be supplied to the respective drives, and a control system operative to compare the generated axes command pulses with vector command data introduced into the apparatus and to produce feed pulses controlling the path generator system, said latter control system comprising: means for converting the vector command data to a train of vector command pulses; a vector command register accumulated said vector command pulses; an axis command register for each axis accumulating the command pulses of its respective axis; an error register; means effective upon the occurrence of each axis command pulse for summing, according to one sign, the count of the respective axis register into the error register; means effective upon the occurrence of each vector command pulse for summing, according to the opposite sign, the count of the feedrate command register into the error register; and means enabling the path generator system to generate axis command pulses only when the count in the error register is of said opposite sign.

Claim 11

Apparatus for generating axis command pulses to be supplied to at least two drives having mutually orthogonal axes of motion to produce a resultant movement of a member in accordance with a predetermined path, comprising, a path generator system operative to generate, in response to axes command data introduced into the apparatus, a train of axes command pulses for each axis to be supplied to the respective drives, and a control system operative to compare the generated axes command pulses with vector command data introduced into the apparatus and to produce feed pulses controlling the path generator system, said latter control system comprising: means for converting the vector command data to a train of vector command pulses; a vector command register accumulated said vector command pulses; an axis command register for each axis accumulating the command pulses of its respective axis; an error register; means effective upon the occurrence of each axis command pulse for summing, according to one sign, the count of the respective axis register into the error register; means effective upon the occurrence of each vector command pulse for summing, according to the opposite sign, the count of the feedrate command register into the error register; and means enabling the path generator system to generate axis command pulses only when the count in the error register is of said opposite sign.

Claim 12

Apparatus for generating axis command pulses to be supplied to at least two drives having mutually orthogonal axes of motion to produce a resultant movement of a member in accordance with a predetermined path and velocity programmed in a program store, the program store including axes command data representing the programmed axes distances and feedrate command data representing the programmed vector velocity, the apparatus comprising a path generator system operative to generate, in response to the program store axes command data, a train of axes command pulses for each axis to be supplied to the respective drives, and a velocity control system operative to compare the program store feedrate command data with the vector velocity that is the resultant of said generated axes command pulses and to produce feed pulses controlling the path generator system such that said resultant vector velocity will correspond to said program store feedrate command data; said velocity control system comprising means for converting the feedrate command data to a train of feedrate command pulses; a feedrate command register accumulating said feedrate command pulses; an axis command register for each axis, accumulating the command pulses for its respective axis; an error register; means effective upon the occurrence of each axis command pulse for adding the count in the respective axis command register into the error register; means effective upon the occurrence of each feedrate command pulse for subtracting the count in the feedrate command register from the error register; means enabling the path generator system to generate axis command pulses only when the count in the error register is negative; means for clearing all said registers when the feedrate command register reaches the limit of its capacity; and means for clearing all said registers upon receiving a new motion command from the program store.

Claim 13

Apparatus for generating axis command pulses to be supplied to at least two drives having mutually orthogonal axes of motion to produce a resultant movement of a member in accordance with a predetermined path and velocity programmed in a program store, the program store including axes command data representing the programmed axes distances and feedrate command data representing the programmed vector velocity, the apparatus comprising a path generator system operative to generate, in response to the program store axes command data, a train of axes command pulses for each axis to be supplied to the respective drives, and a velocity control system operative to compare the program store feedrate command data with the vector velocity that is the resultant of said generated axes command pulses and to produce feed pulses controlling the path generator system such that said resultant vector velocity will correspond to said program store feedrate command data; said velocity control system comprising means for converting the feedrate command data to a train of feedrate command pulses; a feedrate command register accumulating said feedrate command pulses; an axis command register for each axis, accumulating the command pulses for its respective axis; an error register; means effective upon the occurrence of each axis command pulse for adding the count in the respective axis command register into the error register; means effective upon the occurrence of each feedrate command pulse for subtracting the count in the feedrate command register from the error register; means enabling the path generator system to generate axis command pulses only when the count in the error register is negative; means for clearing all said registers when the feedrate command register reaches the limit of its capacity; and means for clearing all said registers upon receiving a new motion command from the program store.