METHOD OF CURVATURE CONTROLLED DATA SMOOTHING

• US 20070085850A1
• Filed: 03/23/2006
• Published: 04/19/2007
• Est. Priority Date: 03/23/2005
• Status: Active Grant

• Current Assignee: Hurco Companies, Inc.
• Original Assignee: Hurco Companies, Inc.
• Inventors: Hong, Jiawei, Tan, Xiaonan
• Granted Patent: US 7,693,588 B2
• Time in Patent Office: Days
• US Class Current: 345/442
• 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 19/4103 Digital interpolation
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 19/4163 Adaptive control of feed or cutting velocity without NC B23Q15/12
• CPC Class Codes: G05B 2219/34171 Generate polynomial fitting in tolerance zone around polygon
• CPC Class Codes: G05B 2219/34175 Overlap, between two blocks, continuous, smooth speed change, movement
• CPC Class Codes: G05B 2219/43057 Adjust acceleration, speed until maximum allowable moment for axis
• CPC Class Codes: G05B 2219/43199 Safety, limitation of feedrate
• CPC Class Codes: G05B 2219/43203 Limitation of speed, permissible, allowable, maximum speed
• CPC Class Codes: G05B 2219/50179 Dynamic tolerance, limit values as function of speed, type of command

Abstract

The present invention involves a method of adjusting path data for a motive body includes identifying four consecutive points of the path data. The four consecutive points include a first point, a second point, a third point and a fourth point. It is determined whether the second point is suitable for smoothing. If the second point is suitable for smoothing, then a first arc and a second arc are located, and the second point is moved into an area between the first arc and the second arc. The first arc is defined by the first point, the second point and the fourth point. The second arc is defined by the first point, the third point and the fourth point. A line move associated with the second point is replaced with at least one arc move associated with the second point.

Claims

1. A method of adjusting path data for a motive body, said method comprising the steps of:

identifying four consecutive points of the path data including a first point, a second point, a third point and a fourth point;

determining whether the second point is suitable for smoothing;

if the second point is suitable for smoothing, then;

locating a first arc defined by the first point, the second point and the fourth point;

locating a second arc defined by the first point, the third point and the fourth point;

moving the second point into an area between the first arc and the second arc; and

replacing a line move associated with the second point with at least one arc move associated with the second point.

2. The method of claim 1 wherein the at least one arc move is tangent to both a preceding move and a succeeding move.

3. The method of claim 1 wherein the at least one arc move comprises two arc moves, the two arc moves being tangent to one another.

4. The method of claim 1 comprising the further step of moving the third point into the area between the first arc and the second arc.

5. The method of claim 1 wherein the line move and the at least one arc move are also associated with the third point.

6. The method of claim 1 comprising the further steps of:

identifying a fifth consecutive point succeeding the fourth point;

determining whether the third point is suitable for smoothing;

if the third point is suitable for smoothing, then;

locating a third arc defined by the second point, the third point and the fifth point;

locating a fourth arc defined by the second point, the fourth point and the fifth point;

moving the third point into an area between the third arc and the fourth arc; and

replacing a line move associated with the third point with at least one arc move associated with the third point.

7. A method of adjusting path data for a motive body, said method comprising the steps of:

identifying three consecutive points of the path data;

ascertaining at least one of;

a first distance between a circular arc defined by the three points and a middle portion of a first line extending between a first of the points and a second of the points; and

a second distance between the circular arc and a middle portion of a second line extending between the second point and a third of the points;

determining a turn angle between the first line and the second line; and

performing smoothing on the second point if;

at least one of the first distance and the second distance is less than a threshold distance; and

the turn angle is greater than a threshold angle.

8. The method of claim 7 wherein smoothing is performed on the second point if a first move from the first point to the second point comprises a first line move and a second move from the second point to the third point comprises a second line move.

9. The method of claim 8 wherein the step of performing smoothing includes replacing at least one of the first line move and the second line move with at least one arc move.

10. The method of claim 7 wherein the threshold line distance is approximately between 0.0002 inch and 0.001 inch.

11. The method of claim 7 wherein the threshold angle is approximately between 130 degrees and 160 degrees.

12. The method of claim 7 wherein the first distance is between the circular arc and a midpoint of the first line, and the second distance is between the circular arc and a midpoint of the second line.

13. The method of claim 12 wherein smoothing is performed on the second point if each of the first distance and the second distance is less than the threshold distance.

14. A method of adjusting path data for a motive body, said method comprising the steps of:

identifying four consecutive points of the path data including a first point, a second point, a third point and a fourth point;

locating a first arc defined by the first point, the second point and the fourth point;

locating a second arc defined by the first point, the third point and the fourth point; and

moving the second point into an area between the first arc and the second arc.

15. The method of claim 14 wherein the second point is moved in a direction toward a closest point on the second arc.

16. The method of claim 14 comprising the further step of moving the third point into the area between the first arc and the second arc.

17. The method of claim 16 comprising the further step of determining whether the first point, the second point and the third point are suitable for smoothing.

18. The method of claim 17 wherein:

if each of the first point, the second point and the third point is suitable for smoothing, moving the second point less than 45% of a distance between the second point and the second arc;

if the second point is suitable for smoothing, one of the first point and the third point is suitable for smoothing, and an other of the first point and the third point is not suitable for smoothing, moving the second point approximately between 45% and 55% of a distance between the second point and the second arc; and

if the second point is suitable for smoothing, and neither of the first point and the third point is suitable for smoothing, leaving the second point unmoved.

19. The method of claim 18 comprising the further steps of:

identifying a fifth consecutive point succeeding the fourth point;

locating a third arc defined by the second point, the third point and the fifth point;

locating a fourth arc defined by the second point, the fourth point and the fifth point; and

moving the third point and the fourth point into an area between the third arc and the fourth arc.

20. The method of claim 16 wherein the second point is moved in a direction toward a closest point on the second arc, and the third point is moved in a direction toward a closest point on the third arc.

21. A method of adjusting path data for a motive body, said method comprising the steps of:

identifying a line move extending from a first point of the path data to a second point of the path data; and

replacing the line move with a first arc move and a second arc move, the first arc move beginning at the first point and terminating at a junction point, the second arc move beginning at the junction point and terminating at the second point.

22. The method of claim 21 wherein the first arc move is tangent to a preceding move at the first point.

23. The method of claim 21 wherein the first arc move is tangent to the second arc move at the junction point.

24. The method of claim 21 wherein the second arc move is tangent to a succeeding move at the second point.

25. The method of claim 21 wherein the first arc move has a first radius and the second arc move has a second radius different from the first radius.