Digitizing control equipment utilizing normal vector calculations and a position sensor

• US 5,266,811 A
• Filed: 07/01/1992
• Issued: 11/30/1993
• Est. Priority Date: 11/08/1990
• Status: Expired due to Fees

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Matsuura, Hitoshi
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): DAVENPORT, TERESA
• Application Number:
  US07/877,184
• Time in Patent Office: 517 Days
• Field of Search: 250/560, 250/561, 356/376
• US Class Current: 250/559.23
• CPC Class Codes: B23Q 35/128 Sensing by using optical means
• CPC Class Codes: G05B 19/41 characterised by interpolation, e.g. the computation of intermediate points between programmed end points to define the path to be followed and the rate of travel along that path G05B19/25, G05B19/31, G05B19/37, G05B19/39, G05B19/40 take precedence
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded

Abstract

A digitizing control device which is inexpensive and capable of generating a normal vector representing the direction of a normal line to a model surface on a real-time basis by a light-section method, wherein a table (31), on which a model (6) is placed, is horizontally moved relative to a tracer head (4) to which a light source (5a) and a camera (5b) are mounted, and a processor (11) of a control device (1) periodically samples measurement data representing two detection points, at which a received-light pattern on the camera crosses two one-dimensional optical sensors arranged at a light-receiving face of the camera, and table/camera movement control data, generates tracing data in accordance with the coordinates of two points on the model surface obtained from the sampled data, calculates a normal vector of the model surface on the basis of the coordinates of the two points and the coordinates of a point on the model surface obtained at a previous sampling time, and positions the tracer head at a rotational position corresponding to the normal vector so that the slit light accurately fall upon the camera.

Claims

1. A digitizing control device for generating tracing data representing a model shape while carrying out a non-contact tracing of a model surface, comprising:

a light-projecting section for projecting a slit light onto the model surface;

a light-receiving section for receiving the slit light reflected from the model surface;

movement control means for moving the light-projecting section and the light-receiving section along the model surface relative to the model in accordance with movement control data;

a position sensor for simultaneously measuring two-dimensional positions of at least two points on the model surface in accordance with a received-light pattern obtained at the light-receiving section, and generating measurement data representing the two-dimensional positions of said at least two points; and

vector calculating means for calculating a normal vector of a slit-light-irradiated portion of the model surface in accordance with the movement control data and the measurement data.

2. The digitizing control equipment according to claim 1, which further comprises a tracer head, to which the light-projecting section and the light-receiving section are fixed, the movement control means moving the tracer head along the model surface with the tracer head being spaced from the model surface.

3. The digitizing control equipment according to claim 1, which further comprises two one-dimensional optical sensors arranged on a light-receiving face of the light-receiving section extending parallel to each other, and rotation control means for positioning the two optical sensors at a rotational position such that the received-light pattern crosses both the optical sensors.

4. The digitizing control equipment according to claim 1, wherein said vector calculating means includes memory means for storing measurement data representing a two-dimensional position of at least one point on the model surface to which the slit light was already irradiated, and calculating means for specifying three points on the model surface in accordance with the measurement data read from the memory means, the data generated by the position sensor and representing the two-dimensional positions of said at least two points on the model surface and the movement control data, as well as for calculating an outer product of two surface vectors both having a start point at one of the three points, as the normal vector.

5. The digitizing control equipment according to claim 1, wherein the position sensor simultaneously measures two-dimensional positions of at least three points on the model surface in accordance with a received-light pattern of two slit lights.