Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Neyland on August 26, 2011, 03:19:53 AM

Title: Curve smoothing, CV, and processing.
Post by: Neyland on August 26, 2011, 03:19:53 AM
Hi Guys,

I have been doing research on curve smoothing in general and the constant velocity function in Mach 3. I have read the CVSettings document however it does not provide a lot of detail on any of the processes.

1). First of all, does anybody have a general understanding of curve smoothing or constant velocity functions and how they actually work?
     Does Mach 3 interpolate curves between separate points, or does it fit a curve between multiple points.
     Or am i totally off track and its achieve some other way?

2). Is curve speed limited by motor acceleration and tolerance only or can it be limited by computer processing speeds? Are there any other factors affecting these speeds?

3). Has anybody looked into interpolatory compensation and look-up tables for compensation of sagged axis? If so, could you please enlighten me with your knowledge.

4). I would like to thank the entire Mach 3 community for such a plethora of user knowledge and genuine interest.

Cheers  :D
Title: Re: Curve smoothing, CV, and processing.
Post by: ger21 on August 26, 2011, 08:10:59 AM
1) Afaik, you're totally off track. Mach3 attempts to follow the actual path. In order to try to maintain constant velocity, it "blends" corners by starting the direction change a little earlier. The amount of blend is mostly determined by the current feedrate and the machines acceleration.
The majority of CV options provide different methods to reduce the blending.

Contrary to your belief, mach3 is actually blending at the points, rather than in between them.

2) Acceleration is the main factor.

3) You might want to look into formulas, but the fact that they don't work while jogging can lead to some problems.