Appendix-620 Spline interpolation
7Appendix
When a continuous arc is designated, depending on the path points the arc may
have a sharp return point as shown in the following drawing. If the spline cancel
does not function and decelerate to stop does to take place between the connec-
tions of adjacent arcs, a sharp reversal will take place. Take special care to the
shape of the generated arc curve.
■Spline cancel
To create a corner edge at path points having a large change in movement direction instead of passing
through them with a smooth spline curve, designate the cancel angle to split the spline curve at that path
point.
Fig.7-18:Spline cancel
For example, to create a corner edge at the path point n shown in Fig. 7-18, if a smaller angle than the angle
θn created by path point n’s previous and next blocks (block n-1 and block n) is set as the cancel angle, the
spline curve will be split at path point n. The robot will decelerate to a stop once at the path point n where the
spline curve is split, and then will accelerate and execute the remaining interpolation.
The cancel angle setting range is shown below. This angle can be set individually for each spline interpola-
tion.
Setting range: 0 to 180 degrees (1 degree increments)
* Spline cancel does not function when 0 degrees is set.
* The default value is 120 degrees.
Relation of arc designation and other path point adjustment functions
Tolerance and block length ratio do not function on a block that draws an arc. Spline cancel does not
function on the arc's transit points (path point n+1). For the start point (path point n) and end point (path
point n+2), if the angle created by the previous and next block is larger than the cancel angle, the move-
ment will decelerate to a stop once.
Path point n
経路点
n-1 n
n+1
θ
n
n-1 n
n+1
ブロックn-1
ブロックn
スプライン
キャンセル
スプライン曲線を分割
θ
n
＞キャンセル角度
Path point
Block n-1
Block n
Spline
cancel
Split spline curve
Cancel angle
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