Controller, forming machine, and control method

1. A controller for controlling operation of a forming machine for forming a workpiece, comprising:

a non-transitory memory storing information; and

one or more hardware processors coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to cause the controller to perform operations comprising:

acquiring, from a depth sensor which outputs image data for determining a distance in a height direction by sensing a predetermined area including a machining area of the forming machine, first image data not including an image of the workpiece and an operator of the forming machine, and second image data representing a current state of the predetermined area during operation of the forming machine, as the image data;

calculating difference data indicating a difference between the first image data and the second image data;

determining an area of the workpiece based on the difference data;

determining a flat area of the workpiece as the determination of the area of the workpiece, wherein the workpiece has a flat worked surface;

determining an area of the operator in the predetermined area based on the difference data; and

controlling operation speed of the forming machine based on the difference data.

2. The controller according to claim 1 , the operations further comprising:

dividing a difference image based on the difference data into a plurality of cells, and to calculate a HOG (Histogram of Oriented Gradients) feature value in the difference data for each of the cells, and

calculating similarity between the HOG feature value and a feature value of a shape of the workpiece for each of the cells, and

wherein the area of the operator and the area of the workpiece is determined based on the calculated similarity.

3. The controller according to claim 2 , wherein the operations further comprise:

determining that an area including a prescribed proportion or more of the cells in which the similarity is less than a reference value is the area of the operator.

4. The controller according to claim 2 , wherein the operations further comprise:

determining that an area including a prescribed proportion or more of the cells in which the similarity is equal to or greater than a reference value is the area of the workpiece.

5. The controller according to claim 1 , the operations further comprising:

dividing a difference image based on the difference data into a plurality of cells, and to calculate a normal vector of an edge portion in the difference data for each of the cells, and

calculating similarity between the normal vector and a vector representing a feature of a shape of the workpiece for each of the cells, and

wherein the area of the operator and the area of the workpiece is determined based on the calculated similarity.

6. The controller according to claim 5 , wherein the operations further comprise:

determining that an area including a prescribed proportion or more of the cells in which the similarity is less than a reference value is the area of the operator.

7. The controller according to claim 5 , wherein the operations further comprise:

determining that an area including a prescribed proportion or more of the cells in which the similarity is equal to or greater than a reference value is the area of the workpiece.

8. The controller according to claim 1 , wherein the operations further comprise:

determining an inclined area inclined at a prescribed angle based on the difference data, and

limiting the operation speed when the inclined area is equal to or larger than a predetermined size.

9. A forming machine for forming a workpiece, comprising:

a body having a machining area where the workpiece is machined;

a controller for controlling operation of the forming machine; and

a depth sensor which outputs image data for determining a distance in a height direction by sensing a predetermined area including the machining area of the forming machine,

the controller being configured to:

acquire, from the depth sensor, first image data not including an image of the workpiece and an operator of the forming machine, and second image data representing a current state of the predetermined area during operation of the forming machine, as the image data,

determine all area of the workpiece based on the difference data;

determine a flat area f the workpiece as the determination of the area of the, workpiece, wherein the workpiece has a flat worked surface;

determine an area of the operator in the predetermined area based on difference data indicating a difference between the first image data and the second image data, and

control operation of the forming machine based on a result of the determination.

10. The forming machine according to claim 9 , wherein the depth sensor is mounted on the body above the machining area.

11. A control method for controlling operation of a forming machine for forming a workpiece, comprising:

acquiring, from a depth sensor which outputs image data for determining a distance in a height direction by sensing a predetermined area including a machining area of the forming machine, first image data not including an image of the workpiece and an operator of the forming machine, as the image data;

after acquiring the first image data, acquiring, from the depth sensor, second image data representing a current state of the predetermined area during operation of the forming machine, as the image data;

calculating difference data indicating a difference between the first image data and the second image data;

determining an area of the workpiece based on the difference data;

determining a flat area of the workpiece as the determination of the workpiece, wherein the workpiece has a flat worked surface;

determining an area of the operator in the predetermined area based on the difference data; and

controlling operation of the forming machine based on a result of the determination.

12. A controller for controlling operation of a forming machine for forming a workpiece, comprising:

a non-transitory memory storing information; and

one or more hardware processors coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to cause the controller to perform operations comprising:

acquiring, from a sensor which outputs image data for determining a distance in a height direction by sensing a predetermined area including a machining area of the forming machine, first image data not including an image of the workpiece and an operator of the forming machine, and second image data representing a current state of the predetermined area during operation of the forming machine, as the image data;

calculating difference data indicating a difference between the first image data and the second image data;

determining an area of the operator in the predetermined area and an inclined area inclined at a prescribed area based on the difference data; and

controlling operation speed of the forming machine based on the difference data, wherein the operation speed is limited when the inclined area is equal to or larger than a predetermined size.