JP3276534B2 - Shape measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring method using a coordinate measuring machine.

[0002]

2. Description of the Related Art In a design department and a design department including an automobile design department and a home appliance, a modeler (a worker who creates a model) creates a model for product design evaluation using clay or resin. After the model is evaluated and corrected, it is necessary to measure the shape of the model in order to create a product having the same shape. In general, a coordinate measuring machine is used for measuring the shape of the model. Hereinafter, an example of a measurement procedure of a conventional automobile model using the three-dimensional measuring machine will be described.

FIG. 3 shows an outline for explaining a measuring procedure of an automobile model using a three-dimensional measuring machine, and FIG. 4 shows an outline for explaining a character line and a sectional line of an automobile.

As shown in FIG. 3, in a coordinate measuring machine 11 installed adjacent to an automobile, an elevating frame 13 is supported on a fixed frame 12 erected at a predetermined position so as to be vertically movable. A horizontally movable support arm 14 is mounted on the lifting frame 13, and a needle 15 is attached to a hand 15 rotatably mounted on the tip of the support arm 14. ing. Therefore, the operator operates the coordinate measuring machine 11, operates the support arm 14 and the hand 15, and moves the stylus 16 along the outer shape of the vehicle while making contact with the body of the car, and thereby, the coordinates of the contact point. Is read and stored.

[0005] In the case of such an automobile model, as shown in Fig. 4, character lines such as contours of windows and doors, lines representing the characteristics of the body, and cross-section lines indicating the shape of the model at regular intervals are called. Measure the line. In FIG. 4, the character line is represented by a thick line, and the sectional line is represented by a thin line.

[0006]

However, in such a conventional measuring method in which such a worker operates the coordinate measuring machine 11 to measure a model of a car, the model of the car is a modeler. It is a shape created by the (worker) and an unknown shape. Therefore, it is impossible to store or teach the movement locus for measurement in the coordinate measuring machine 11 in advance, and the measurement must be performed manually.

Further, in the case of an actual vehicle-size model of an automobile, the number of measurement points may range from thousands to tens of thousands, and it is difficult for an operator to operate the CMM 11 manually. There is a problem that the working time is long and the working efficiency is not good. Furthermore, since the operator manually performs the measurement operation, the contact points between the body of the automobile and the probe 16 vary, and high measurement accuracy cannot be obtained.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a shape measuring method which improves the efficiency of measuring work.

[0009]

In order to achieve the above-mentioned object, a shape measuring method according to the present invention is characterized in that an intersection of characteristic line data and several sectional line data of a measurement model already measured with a separately designated plane is provided. The line connecting these intersections is regarded as the cross-sectional shape of the model in the corresponding plane, and the movement of the CMM is generated based on the line to automatically measure the cross-sectional shape of the measurement model. It is assumed that.

[0010]

When the characteristic line data of the model and several cross-sectional line data are measured, the general shape of the entire model is grasped, and when measuring the cross-sectional shape of the model, the characteristic line data and several lines already measured are obtained. Determines the intersection of the cross-section line data and the measured section, regards the line connecting the intersection as an approximation of the shape in the measured section of the model, and moves the CMM based on this line to automatically measure the shape. Becomes possible.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a control block diagram of a shape measuring apparatus for performing a shape measuring method according to an embodiment of the present invention.
An outline for explaining the shape measuring method of this embodiment is shown in FIG.

As shown in FIG. 1, the shape measuring apparatus according to this embodiment has an intersection calculator 21, an intersection rearranger 22, a trajectory creator 23, a trajectory modifier 24, and a correction command input device 25.
It is composed of

That is, the intersection calculator 21 receives the character line data of the automobile model and several section line data, and calculates the intersection of the character line data, several section line data, and the measured section data. is there. The intersection rearranging unit 22 rearranges the intersection data calculated in accordance with the measurement procedure, and in this embodiment, the Z coordinates shown in FIG. 2 are in descending order. The trajectory creator 23 creates a trajectory connecting the calculated and rearranged intersections as an automatically measured trajectory.

The correction command input unit 25 inputs correction data to the trajectory correction unit 24 in accordance with a command from an operator for a rapidly changing shape portion or a non-measuring portion on the model of the vehicle. The trajectory corrector 24 corrects the measured trajectory according to the instruction of the correction data.

Therefore, when the character line data and several section line data are input to the intersection calculator 21, the intersection calculator 21 intersects the intersection of the character line data, several section line data, and the measured section data. Is calculated. The intersection rearranging unit 22 rearranges the measurement data in accordance with the measurement procedure. As shown in FIG. 2, a, b, c, d, e, f, g, and h are arranged in descending order of the Z coordinate. Rearrange. The trajectory creator 23 creates a trajectory connecting the obtained intersections as an automatically measured trajectory. In this case, in the case of a contact sensor,
The trajectory is corrected by the length of the sensor, and a movement command of the measuring machine such as approach, retraction, and change of the attitude of the sensor is also created. Similarly, in the case of an optical sensor, the trajectory is corrected so that the measurement trajectory enters the measurement area of the optical sensor. The correction command input unit 25 inputs the correction data to the trajectory correction unit 24 in accordance with a command from the operator for the shape suddenly changing part or the non-measurement part on the model of the vehicle, and the trajectory correction unit 24 performs measurement according to the instruction of the correction data. Modify the trajectory.

Note that such a series of control operations are executed by software of a computer.
Normally, existing measurement data is uploaded by a CAD / CAM workstation, and the processing is performed by interactive operation with an operator.

[0018]

As described above in detail with reference to the embodiments, according to the shape measuring method of the present invention, the characteristic line data and the cross-sectional line data of the measurement model already measured are compared with the plane designated separately. Intersections are determined, the line connecting those intersections is regarded as the cross-sectional shape of the model in the corresponding plane, and the movement of the CMM is generated based on that, and the cross-sectional shape of the measurement model is automatically measured. Therefore, even for an unknown model shape, it is possible to generate a trajectory for automatically measuring the cross-sectional shape of the model simply by measuring some of the lines representing the features of the model, contributing to unmanned measurement. Measurement efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a shape measuring apparatus for performing a shape measuring method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a shape measuring method according to the present embodiment.

FIG. 3 is a schematic diagram for explaining a measurement procedure of an automobile model using a coordinate measuring machine.

FIG. 4 is a schematic diagram for explaining a character line and a cross-sectional line of an automobile.

[Explanation of symbols]

 Reference Signs List 11 Coordinate measuring machine 21 Intersection calculator 22 Intersection rearranger 23 Locus creator 24 Locus corrector 25 Correction command input device

Continued on the front page (72) Inventor Masatoshi Michibata 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Tadashi Kitayama 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) Reference Reference JP-A-3-12511 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 21/20 101 G01B 5/20 101

Claims (1)

(57) [Claims] An intersection between a characteristic line data and several cross-section line data of a measurement model already measured and a separately designated plane is determined, and a line connecting these intersections is regarded as a cross-sectional shape of the model in the corresponding plane. And a method for generating a movement of the coordinate measuring machine based on the information and automatically measuring a cross-sectional shape of the measurement model.