SU637783A1 - Circular interpolator - Google Patents

Description

The invention relates to cr {computed computing devices and can be used in digital p | M systems, and for example. machine tools.

Known devices are a circular interpolation, operating according to the method of evaluation function (}. These iterpol mountains contain X and Y coordinate counters, the outputs of which are connected to the information inputs of the adder and the inputs of the current coordinates, the output of which is connected to the first input of the sector selection and measure block interpolations, the second input of which is connected with the output of the clock generator, pulses, the outputs of the sector selection block and the interpolation cycle are connected to the counting inputs of the coordinate counters and with the corresponding inputs of the totalizer upravleii and for receiving information from the coordinate counter.

The main disadvantage of these interpolators is their low accuracy. The interpolation error in them reaches the interpolation step.

The aim of the invention is to improve the accuracy of circular interpolation.

The goal is achieved by introducing an evaluation unit with a radius of an interpolated circle into the proposed device, the first input of which is connected to the output of the adder, the second input is connected to the radius signal bus, and the output is connected to the corresponding input of the sector selection and tact and iteration circuit.

FIG. I image functional diagram of a circular interpolator; in fig. 2 - an example of interpolation of a circle by this interpolator.

The functional diagram of the circular interpolator includes an accumulator adder with controllable mapping inputs, a reversible counter 2 abscissa X of the current point, a reversible counter 3 ordinates At the current point, block 4 compares the current coordinates A and Y, block 5 of the evaluation function with the radius of the interpolated circle, block 6 sector selection and interpolation cycle, the generator 7 clock pulses. The inputs of unit 5, the comparison of the evaluation function with the radius, are connected to the output of the adder 1 and the signal terminal 8 of the radius value. The outputs 9 and 10 of the block for sector selection and the interpolation cycle are connected respectively to the counting inputs of counters 2 and 3 of the coordinates of the current point and with the corresponding inputs of the adder 1 for controlling the reception of information from the counters of the coordinates. The outputs of the counters 2, 3 are connected to the information inputs of the adder and the inputs of the block 4 comparing the current coordinates. The output of block 4 is connected to the input of the result of comparing the current coordinates of block 6 of the sector selection and interpolation cycle. To the input of the result of the evaluation function with the radius of the interpolated circle and the synchronization input of the block 6 are connected, respectively, the generator output 7 clock pulses and the output of the comparison block 5. The adder is used to calculate the value of the evaluation function f {in each i-th cycle of determining the new coordinates of the current interpolation point. In the counters 2, 3, the calculation of new values is performed according to the abscissa Xi. and ordinate Yi, the current point. Block 4 is used to compare the coordinates of the current interpolation point among themselves. The result of the comparison is used to determine the interpolation sector. Block 5 is used to compare the modulus of the evaluation function with the radius of the interpolated circle. Sector selection and interpolation cycle 6 serves to distribute the pulses from generator 7 to the output buses 9 and 0 of the coordinate change signals in X and Y depending on the comparison results in blocks 4 and 5. For definiteness, the interpolator is described for the first quarter of the plane (X 0, Y 0) when the current interpolation point is “counterclockwise. Each cycle of determining the new coordination of the current interpolation point consists of two cycles. By the beginning of the i-ro | cycle for determining the new coordinates of the current point in the adder I, the value of the estimated function functions P. j. and in counters 2 and 3-Xi-i and, respectively, calculated in the previous (i-1) -th cycle. Block 4 compares the current coordinates Xc-t and Yi-i with each other. According to the result, the equa- tions (or XL-I Yi-t) there are two possible cases of device operation. The first case (Xi-i. YL-i) In the first cycle, the sector selection block 6 and the interpolation cycle produces a pulse on the bar 10, which controls the transfer of the doubled contents of counter 3 to the adder 1. The value of the evaluation function is calculated by the formula F1 F1 in the adder -1 -I- 2YL-1 .4- I. The leading edge of the pulse on the tongue 10 increases by one the contents of the counter 3. The value of the estimated function calculated in the first cycle is compared in unit 5 modulo the radius of the circle. If the module of the evaluation function is less than the radius, then the second cycle is not generated, and the cycle of determining new coordinates of the current prices of the point ends. In the counters 2 and 3, the coordinates are the coordinates Xj, XL-I and YI Yi-i -f {respectively, and in the adder the value of the single-core function ((, which are the basis for the next interpolation cycle. If the estimated function modulo is greater than or equal to the radius of the circle, then in the second cycle, the sector selection block 6 and the interpolation cycle outputs a pulse to bus 9, which controls the double value of the contents of counter 2 to the adder. In the adder, the value of the evaluation function is calculated using the formula H 1-2X1- 1-fl The back edge of the pulse on the cheek 9 decreases The counter of the new coordinates is completed by one at this point. The coordinates of counters 2 and 3 contain the coordinates Xl Xi-i - Yi Yl-i +1, respectively, and in the adder the value of the evaluation function is tfi, which are the original for the next interpolation cycle. The second case (Xi-i Yl-i) Here, in the first cycle, block b generates a pulse on bus 9, which delivers twice the contents of counter 2 to the adder and the falling edge reduces by one the value of the contents of counter 2. In the adder, evaluation function evaluation and by the formula F1 F1 -, - 2X1-1 +5 Then a comparison is made modulo the calculated value of the evaluation function with the radius of the circle in block 5. If the modulus of the evaluation function is less than the radius of the circle, then this interpolation cycle ends. The coordinate counters 2 and 3 contain the coordinates Xi - I and Yi i-i, respectively, and in the adder the values of the evaluation function Pj pf, which are then used in the next interpolation cycle. If the estimated function is modulo larger or equal to the radius, then in the second cycle, the sector selection and interpolation cycle 6 produces a pulse on bus 10 that delivers twice the value of the contents of counter 3 to the adder and the falling edge increases by one the content of this counter. In the adder, the evaluation function is calculated using the formula G: - + 2Yi-, + This completes the cycle for determining new coordinates, the coordinates Xi Xt-i - 1 and Yi Yi-i are found in counters 2 and 3, and in the adder - the evaluation function f-fi. The work of the interpolator in the other quarters is similar. FIG. Figure 2 shows a graph of the interpolated circle by this interpolator when the current interpolation point “moves counterclockwise. The radius of the circle is ten samples.