G Code Generation

I need understand more about how LinuxCNC work in trajectory planner and lookahead. Exist any document about this?Or how can I learn about this themes?

From the user side there is this chapter

linuxcnc.org/docs/html/common/User_Concepts.html

From a programmer side you would have to examine the code.

John

I have readed linuxcnc.org/docs/html/common/User_Concepts.html. In critical distance say that A is 1/2 of Max aceleration but in the examples use the complete aceleration.

I'm not sure if your asking a question or not? If you are can you describe it a bit differently?

John

Ok.

There is a possibility of bug in the examples of Section 1.4. The theory says that A is half of the maximum acceleration but the examples used without dividing the maximum acceleration for two

To keep up the feed rate, the move must be longer than the distance it takes to accelerate from 0 to the desired feed rate and then stop again. Using A as 1/2 the ini file MAX_ACCELERATION and F as the feed rate in units per second, the acceleration time is ta = F/A and the acceleration distance is da = F*ta/2. The deceleration time and distance are the same, making the critical distance d = da + dd = 2 * da = F2/A.

For example, for a feed rate of 1 inch per second and an acceleration of 10 inches/sec2, the critical distance is 12/10 = 1/10 = 0.1 inches.

For a feed rate of 0.5 inch per second, the critical distance is 52/100 = 25/10 = 0.025 inches.

So your saying the two examples from the manual I quoted above are wrong? What should the correct example be?

John