Analog-to-digital converter for positional coordinates

Claim 1

A digitizing system for producing a digital representation of a line in a rectangular coordinate system having X- and Y-axes, said system comprising; a resolver adapted to receive an angular input signal and to develop first and second output signals corresponding respectively to the cosine and sine of the angular input signal, a tracer connected with the resolver for supplying a direction angle input signal thereto corresponding to the direction angle between adjacent points on the line, an X-axis pulse generator connected with the cosine output of said resolver and adapted to produce output pulses having a pulse repetition rate corresponding thereto, a Y-axis pulse generator connected with the sine output of said resolver and adapted to produce output pulses having a pulse repetition rate corresponding thereto, an X-axis pulse stepping motor connected with the X-axis pulse generator and responsive to the output pulses thereof to produce relative displacement of the tracer and the line corresponding to the number of pulses generated thereby, a Y-axis pulse stepping motor connected with the Y-axis pulse generator and responsive to the output pulses thereof to produce relative displacement of the tracer and the line corresponding to the number of pulses generated thereby, said X-axis and Y-axis pulse stepping motors being connected to produce said relative displacement in accordance with said direction angle whereby the positional coordinates of successive points are represented by the number of pulses produced by the X-axis and Y-axis pulse generators corresponding thereto, a quadrant-switching means connected between said resolver and said pulse generators and adapted to selectively switch the output of each pulse generator between a reference phase and a quadrature phase in accordance with the quadrant of said direction angle whereby said pulse stepping motors are rotated in a forward direction in response to pulses of the reference phase and are rotated in a reverse direction in response to pulses of the quadrature phase, and whereby the accuracy of such digitized positional coordinates is verified by the displacement of the tracer to said successive points.

Claim 4

A system for use in generating digital data for use in controlling numerically controlled machine tools and comprising: support means adapted to receive an object with a line representing the contour of a workpiece, tracing means having a direction indicating member adapted to be aligned with the direction angle of said line at any point thereon, first and second pulse stepping motors for displacing one of said means along respectIve first and second axes, a sine-cosine resolver having its input operatively connected with the indicating member and adapted to produce first and second output signal quantities corresponding respectively to the sine and cosine of said direction angle, first and second pulse generators operatively connected with said resolver and responsive to the respective output signal quantities to produce output pulses having a pulse repetition rate corresponding thereto, said first and second pulse generators being connected respectively with said first and second pulse stepping motors for controlling energization thereof, a quadrant-switching means connected between said resolver and said pulse generators and adapted to selectively switch the output of each pulse generator between a reference phase and a quadrature phase in accordance with the quadrant of said direction angle whereby said pulse stepping motors are rotated in a forward direction in response to pulses of the reference phase and are rotated in a reverse direction in response to pulses of the quadrature phase, whereby said one of said means is displaced along each axis a distance corresponding to the number of pulses and at a rate corresponding to the repetition frequency of the respective pulse generator so that said indicating member is maintained in alignment with the direction angle of the line.

Claim 5

A system for use in generating digital data for use in controlling numerically controlled machine tools and comprising: support means adapted to receive an object with a line representing the contour of a workpiece, tracing means having a direction indicating member adapted to be aligned with the direction angle of said line at any point thereon, first and second pulse stepping motors for displacing one of said means along respectIve first and second axes, a sine-cosine resolver having its input operatively connected with the indicating member and adapted to produce first and second output signal quantities corresponding respectively to the sine and cosine of said direction angle, first and second pulse generators operatively connected with said resolver and responsive to the respective output signal quantities to produce output pulses having a pulse repetition rate corresponding thereto, said first and second pulse generators being connected respectively with said first and second pulse stepping motors for controlling energization thereof, a quadrant-switching means connected between said resolver and said pulse generators and adapted to selectively switch the output of each pulse generator between a reference phase and a quadrature phase in accordance with the quadrant of said direction angle whereby said pulse stepping motors are rotated in a forward direction in response to pulses of the reference phase and are rotated in a reverse direction in response to pulses of the quadrature phase, whereby said one of said means is displaced along each axis a distance corresponding to the number of pulses and at a rate corresponding to the repetition frequency of the respective pulse generator so that said indicating member is maintained in alignment with the direction angle of the line.