Browse Prior Art Database

# Numerical Control

IP.com Disclosure Number: IPCOM000075091D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 36K

IBM

## Related People

Warsewa, HR: AUTHOR

## Abstract

In order to limit the amount of data for numerical control of tool 4, these data are compressed before being stored in storage 1 and expanded again in control unit 2. The compressed data consists of selected coordinate values (e.g. R, x, y) or other values (e.g. temperature, pressure) and their derivations. For expanding the data, control unit 2 approximates from a fed-in value group strings of the missing consecutive value groups.

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Numerical Control

In order to limit the amount of data for numerical control of tool 4, these data are compressed before being stored in storage 1 and expanded again in control unit 2. The compressed data consists of selected coordinate values (e.g. R, x, y) or other values (e.g. temperature, pressure) and their derivations. For expanding the data, control unit 2 approximates from a fed-in value group strings of the missing consecutive value groups.

A coordinate point and its derivations are expressed by the following formulas: R(T) = AT/n/+BT/n-1/+CT/n-2/+...+IT/5/+JT/4/+KT/3/+LT/2/IMT+N R'(T) = nAT/n-1/+(n-1)BT/n-2/+...+5IT/4/+4JT/3/+ 3KT/2/+2LT+M R"(T) = n(n-1)AT/n- 2/+(n-1)(n-2)BT/n-3/+...20IT/3/+12JT/2/+6KT+2L etc.

in these formulas R is a coordinate value, T is the time, A,B,C... N are factors. If for simplification n is made 3, the formulas are reduced to: R(T) = AT/3/+BT/2/+CT + D R'(T) = 3AT/2/+ 2BT + C R"(T) = 6AT + 2B R"'(T) = 6A For T = 0, the selected group of values is reduced to: R(0) = D R'(0) = C R"(0) = 2B R'"(0) = 6A.

From this selected group of values control unit 2 approximates the consecutive groups of values with the following Taylor formulas: R(T+1) = R(T) + R'(T) + R"(T) over 2 + R'"(T) over 6 R'(T+1) = R'(T) + R"(T) + R"'(T) over 2 R"(T+1) = R"(T) + R"'(T) R"'(T+1) = R"'(T) = 6A = constant.

Since for calculating R"'(T)/6 a division operation is necessary, R"'(T)/3 is stored in storage 1 instead of R"'(T) if a binary code is used. Having stored R"'(T)/3, all above Taylor formulas can be calculated by simply adding and shifting (division by two). R"'(T)/2 can be computed according to R"'(T)/2 = R"'(T)/3 + 1/2 R"'(T)/3.

Because the consecutive recomputation in control unit 2 is performed by using approximation formulas, the comparison of the approximate values against the values stored in storage 1 might indicate growing deviations after a number of cycles. Counter value 2, indicating the number of cycles over which the approximated values do not deviate by more than a given tolerance from the values, is appended to the initial group of values.

In control unit 2, Z is decremented one increment each time a new value group has been approximated. If Z = 0, a new group of selecte...