Automatic deceleration to zero velocity in iteratively computing numerical control systems

Claim 3

The method set forth in claim 1 wherein i. said changeable first number is PVA, ii. said distance Delta U is equal to PVA. Delta T, iii. said changeable second number is Rp Uep-Upp, iv. said changeable third number signaled during each period Delta T is equal to Rp(1-C)/ Delta T, and v. said step (f) includes setting the first number PVA equal to Rp(1-C)/ Delta T during each period Delta T when PVA > or = Rp(1-C)/ Delta T.

Claim 4

The method set forth in claim 1 wherein i. said first changeable number is Delta U ii. said step (c) includes moving the element Delta U per Delta T and at a velocity equal to Delta U/ Delta T where Delta T is a predetermined constant, iii. said changeable second number signaled during each period Delta T is Rp Uep-Upp, iv. said changeable third number signaled during each period Delta T is equal to Rp(1-C), and v. said step (f) includes setting the first number Delta U equal to Rp(1-C) during each period Delta T when Delta U > or = Rp(1-C).

Claim 5

The method set forth in claim 1 wherein said step (f) includes setting said first number equal to said third number during any period Delta T when the first number exceeds the third number and is also greater than a predetermined constant representing a creep speed Vf, whereby the velocity of the element prior to reaching the end point does not fall below Vf,

Claim 6

The method set forth in claim 2 wherein said changeable third number is equal to Rp(1-C)/ Delta T + M, where M is predetermined constant representing a minimum velocity Vf to which PVA will be reduced as Rp reaches zero.

Claim 7

The method set forth in claim 2 wherein said changeable third number is equal to Rp(1-C) + M, where M is a predetermined constant and M. Delta T represents a minimum velocity Vf to which the elements velocity can be reduced as Rp reaches zero.

Claim 10

The method set forth in claim 7, wherein said step (e) includes computing and signaling during each period Delta T a look-ahead distance number LAD which is proportional to the value of

Claim 11

The method set forth in claim 8 wherein said distance number LAD is computed and signaled as being equal to (V0. Delta T)/(1-C).

Claim 12

The method set forth in claim 7, wherein said step (e) includes computing and signaling during each period Delta T a look-ahead distance number LAD which is proportional to the value ( Delta U)/(1-C), where Delta U is the then existing value of the quantity Delta U named in step (c).

Claim 13

The method set forth in claim 7, wherein said step (e) includes computing and signaling during each period Delta T a look-ahead distance number LAD which is proportional to said first number and therefore proportional to ( Delta U)/( Delta T(1-C)).

Claim 14

The method set forth in claim 10 wherein said step (f) includes comparing during each period Delta T the then existing value of Delta U with the then existing value of Rp(1-C), and changing said first number to said fraction C of its previous value during each period Delta T after such comparing first indicates that the first of the two compared values equals or exceeds the second.

Claim 15

The method set forth in claim 11, wherein said step (f) includes comparing during each period Delta T the then existing value of said first number with the then existing value of (Rp (1-C))/ Delta T and changing said first number to said fraction C of its previous value during the Delta T periods following that in which the first of the two compared values equals or exceeds the second.

Claim 16

The method set forth in claim 10 wherein said step (f) further includes said changing of the values of said signaled first number by making it equal to Rp (1-C).

Claim 17

The method set forth in claim 13, wherein said step (f) further includes said changing of said signaled first number by setting it to a new value which is equal to the then existing value of (Rp(1-C))/ Delta T.

Claim 18

In a system wherein a movable element is translated at a velocity corresponding to a signaled number PVA by causing the element to move through a distance correspoNding to a signaled number Delta U during each of successive equal time periods Delta T, where the signaled number PVA is changeable from instant to instant and the signaled number Delta U is proportional to PVA X Delta T during each period Delta T, the method of signaling on a substantially continuous basis the distance LAD which the element will travel before reaching zero velocity if, beginning during any period Delta To, its velocity PVA is changed to a predetermined fraction C (where C is a constant less than 1.0 ) of the previous value during each of the subsequent periods Delta T, said method comprising computing and signaling during each period Delta T a number LAD which is equal to V0. Delta T. 1/(1-C), where V0 is the value of PVA during that period.

Claim 19

In a system wherein a movable element is translated at a velocity corresponding to a signaled number PVA by causing the element to move through a distance correspoNding to a signaled number Delta U during each of successive equal time periods Delta T, where the signaled number PVA is changeable from instant to instant and the signaled number Delta U is proportional to PVA X Delta T during each period Delta T, the method of signaling on a substantially continuous basis the distance LAD which the element will travel before reaching zero velocity if, beginning during any period Delta To, its velocity PVA is changed to a predetermined fraction C (where C is a constant less than 1.0 ) of the previous value during each of the subsequent periods Delta T, said method comprising computing and signaling during each period Delta T a number LAD which is equal to V0. Delta T. 1/(1-C), where V0 is the value of PVA during that period.

Claim 20

The method set forth in claim 16 further characterized in that the number LAD is computed and signaled during each period Delta T as being equal to Delta U/(1-C).

Claim 21

The method set forth in claim 16 further including the step of signaling, during any period Delta T, that the distance LAD is greater than a remaining distance Rp, and wherein during each period Delta T two numbers respectively proportional by the same factors to Delta U and Rp(1-C) are compared, and signal SDZ is produced whenever the former number exceeds the latter.

Claim 22

In a method for controlling the velocity of a movable element by iteratively incrementing a signaled number USC by amounts Delta U during successive equal time periods Delta T and causing the element to move dynamically along an axis U in accordance with changes in the number USC, the velocity of the element thus being proportional to Delta U/ Delta T and determined by the incrementing amount Delta U, the improvement for decelerating the element to substantially zero velocity and which comprises the steps of a. producing a signal SDZ during the period Delta T when deceleration to zero is to begin, and b. in response to said signal SDZ reducing the incrementing amount Delta U by a predetermined percentage C during each successive period Delta T, such that Delta Un 1 C Delta Un.

Claim 23

In a method for controlling the velocity of a movable element by iteratively incrementing a signaled number USC by amounts Delta U during successive equal time periods Delta T and causing the element to move dynamically along an axis U in accordance with changes in the number USC, the velocity of the element thus being proportional to Delta U/ Delta T and determined by the incrementing amount Delta U, the improvement for decelerating the element to substantially zero velocity and which comprises the steps of a. producing a signal SDZ during the period Delta T when deceleration to zero is to begin, and b. in response to said signal SDZ reducing the incrementing amount Delta U by a predetermined percentage C during each successive period Delta T, such that Delta Un 1 C Delta Un.

Claim 24

The method set forth in claim 19 wherein said step (a) includes a1. signaling during each period Delta T a numerical value Rp representing the distance remaining for the element to travel to reach a stopping point at which its velocity is to be zero, a2. signaling during each period Delta T a numerical value LAD representing the distance which the element will travel if said step (b) is initiated during that particular period, a3. comparing said signaled values LAD and Rp during each period Delta T and producing said signal SDZ when the latter value equals or exceeds the former.

Claim 25

The method set forth in claim 20 wherein said steps (a2) and (a3) include signaling and comparing during each period Delta T the values of Delta U and Rp (1-C) to produce the signal SDZ when the former value equals or exceeds the latter.

Claim 26

The method set forth in claim 21 wherein said step (b) includes setting said incrementing amount Delta U to a new value during each period Delta T such that Delta Un 1 Rp (1-C).

Claim 27

In an apparatus for controlling the velocity of an element movable along a path to a commanded end point, said apparatus including a. means for measuring off successive, equal periods Delta T in actual time, b. means for signaling a first number which is changeable during each Delta T and which is proportional by a given factor to the desired velocity at which the element is to be moved, c. means for moving the member toward the end point a distance Delta U during each period Delta T and controlling said distance Delta U directly or indirectly from said first number to make the velocity Delta U/ Delta T be always substantially equal to said desired velocIty, and d. means for signaling a changeable second number which during each period Delta T represents the remaining distance between the then existing position of the element and said end point, the improvement which comprises e. means for deriving and signaling from said signaled second number a changeable third number which is a function of said remaining distance and which during each period Delta T is proportional by said factor to a schedule velocity, said schedule velocity being that at which said element must then be moving to make its velocity at the end point substantially zero if its velocity is changed to a predetermined fraction C of its previous velocity during each subsequent period Delta T, and f. means for setting said first number equal to said third number during any period Delta T when the first number exceeds the third number.

Claim 28

In an apparatus for controlling the velocity of an element movable along a path to a commanded end point, said apparatus including a. means for measuring off successive, equal periods Delta T in actual time, b. means for signaling a first number which is changeable during each Delta T and which is proportional by a given factor to the desired velocity at which the element is to be moved, c. means for moving the member toward the end point a distance Delta U during each period Delta T and controlling said distance Delta U directly or indirectly from said first number to make the velocity Delta U/ Delta T be always substantially equal to said desired velocIty, and d. means for signaling a changeable second number which during each period Delta T represents the remaining distance between the then existing position of the element and said end point, the improvement which comprises e. means for deriving and signaling from said signaled second number a changeable third number which is a function of said remaining distance and which during each period Delta T is proportional by said factor to a schedule velocity, said schedule velocity being that at which said element must then be moving to make its velocity at the end point substantially zero if its velocity is changed to a predetermined fraction C of its previous velocity during each subsequent period Delta T, and f. means for setting said first number equal to said third number during any period Delta T when the first number exceeds the third number.

Claim 29

In apparatus for controlling the velocity of an element movable along a path U to a commanded end point Uep, said apparatus including a. means for measuring off in actual time successive, equal period Delta T, b. means for signaling a first changeable number proportional to the desired velocity at which the element is to be moved, c. means responsive to the signals representing said first number for driving the element along the path an incremental distance Delta U during each period Delta T to make the actual velocity equal to Delta U/ Delta T, where Delta U is proportional to said first number, d. means for determining and signaling a second changeable number which during each period Delta T represents the remaining distance Rp between the then-existing position of the element and the end point position, the improvement which comprises, in combination e. means responsive to the signals representing said first and second numbers for signaling during each period Delta T a third changeable number representing a look-ahead distance LAD which the element will travel in reaching zero velocity if its then existing actual velocity is decremental during each period Delta T to a predetermined percentage C of its previous value, where C is a constant less than 1.0, and f. means responsive to the signals representing said first, second and third numbers for changing the first number to said predetermined fraction C of its previous value during each period Delta T when said third number equals or exceeds said second number until said first number is reduced to a predetermined minimum value.

Claim 30

In apparatus for controlling the velocity of an element movable along a path U to a commanded end point Uep, said apparatus including a. means for measuring off in actual time successive, equal period Delta T, b. means for signaling a first changeable number proportional to the desired velocity at which the element is to be moved, c. means responsive to the signals representing said first number for driving the element along the path an incremental distance Delta U during each period Delta T to make the actual velocity equal to Delta U/ Delta T, where Delta U is proportional to said first number, d. means for determining and signaling a second changeable number which during each period Delta T represents the remaining distance Rp between the then-existing position of the element and the end point position, the improvement which comprises, in combination e. means responsive to the signals representing said first and second numbers for signaling during each period Delta T a third changeable number representing a look-ahead distance LAD which the element will travel in reaching zero velocity if its then existing actual velocity is decremental during each period Delta T to a predetermined percentage C of its previous value, where C is a constant less than 1.0, and f. means responsive to the signals representing said first, second and third numbers for changing the first number to said predetermined fraction C of its previous value during each period Delta T when said third number equals or exceeds said second number until said first number is reduced to a predetermined minimum value.

Claim 31

The combination set forth in claim 24 further characterized in that said means (e) includes means for signaling during each period Delta T a third changeable number which is equal to V0. Delta . 1/(1-C), where V0 is the velocity at which said element is then moving, Delta T is numerically the length of said time periods, and C is said predetermined percentage.

Claim 32

The combination set forth in claim 24 further characterized in that i. said signaled first number represents numerically a velocity PVA, and said incremental distance Delta U is equal to PVA. Delta T, ii. said means (e) for signaling a third number comprises means responsive to the signals representing said second number for signaling the third number with a value representing Rp(1-C)/ Delta T, iii. said means (f) includes means for setting said first number to a new value PVAi which is equal to said third number during any period Delta T when the first number value PVAi 1 equals or exceeds the value of the third number.

Claim 33

The combination set forth in claim 24 further characterized in that i. said signaled first number represents numerically an incremental distance Delta U, and said means (c) includes means for driving the element, during each period Delta T, an incremental distance which is equal to the value of the first number, ii. said means (e) for signaling a third number comprises means respoNsive to the signals representing said second number for signaling the third number with a value representing Rp(1-C), and iii. said means (f) includes means for setting said first number Delta U to a new value Delta Ui which is equal to said third number during any period Delta T when the first number value Delta Ui 1 equals or exceeds the value of the third number.