Marlin: Circular Nozzle clean

[Core3dTech]

Bug Report

• Description: Circular nozzle cleaning P2 does not make a circular motion
• Expected behaviour: when defining NOZZLE_CLEAN_START_POINT (center) and NOZZLE_CLEAN_CIRCLE_RADIUS and NOZZLE_CLEAN_CIRCLE_FN (assuming this represents slices of circle) nozzle properly goes to start location but does not make circular motion.

code used to create circle currently:

float x, y;
    for (uint8_t s = 0; s < strokes; s++) {
      for (uint8_t i = 0; i < NOZZLE_CLEAN_CIRCLE_FN; i++) {
        x = middle.x + sin((M_2_PI / NOZZLE_CLEAN_CIRCLE_FN) * i) * radius;
        y = middle.y + cos((M_2_PI / NOZZLE_CLEAN_CIRCLE_FN) * i) * radius;

        do_blocking_move_to_xy(x, y);
      }
   } 

Assuming NOZZLE_CLEAN_CIRCLE_FN represents a slice of the circle, the M_2_PI should be 2*M_PI

    float x, y;
    for (uint8_t s = 0; s < strokes; s++) {
      for (uint8_t i = 0; i < NOZZLE_CLEAN_CIRCLE_FN; i++) {
        x = middle.x + sin((2* M_PI / NOZZLE_CLEAN_CIRCLE_FN) * i) * radius;
        y = middle.y + cos((2* M_PI / NOZZLE_CLEAN_CIRCLE_FN) * i) * radius;

        do_blocking_move_to_xy(x, y);
      }
    }

```

[bjarchi]

Confirmed - it looks like the M_2_PI define in Arduino/Math.h is for 2/pi, not 2*pi as someone might expect:

#define M_2_PI      0.63661977236758134308

Later on there's a M_TWOPI define that's correct but it's guarded as follows:

#ifndef __STRICT_ANSI__

#define M_TWOPI         (M_PI * 2.0)
#define M_3PI_4     2.3561944901923448370E0
... 

So I'm not sure if that's available for use or not. Fixing this would be better achieved by using (or creating) a 2*pi constant, rather than doing the extra 2 * M_PI multiplication in each loop iteration IMO.

@thinkyhead This is a bug I could actually fix, but I'm curious about whether that M_TWOPI define is available (and guaranteed to be available across boards/Arduino versions)

[bjarchi]

@mvl03 This should be fixed now in latest bugfix-1.1.x branch (and bugfix-2.0.x). I don't use the nozzle clean feature, so I could only verify that it compiles correctly and that the intent of the code is correct. Can you give it a try on your hardware, and close the issue if it is indeed fixed?

[bjarchi]

@thinkyhead Realized that I can test this since the config gives full control over positioning and Z height.

Tested on bugfix-1.1.x...
G12 P2 S3 - Nozzles goes to the specified point, does a cute little circular dance (3x) and returns to where it started.

[Core3dTech]

excellent. thank you. I created some custom code of my own but I'll have a look at the new code when I get a chance.

[Core3dTech]

Tested the new circular code on my printer and it worked. Thx

[bjarchi]

Thanks for testing!

Are you on bugfix-1.1.x or bugfix-2.0.x? I've also tested on 1.1.x, would be nice to see a test on 2.0.x (although the code change is identical)

[Core3dTech]

To be honest I tested your code snippet from bugfix-1.1.x . I'm not quite ready right now to overwrite my entire installation. I haven't looked at 2.0.x release yet.

[bjarchi]

That's fine - I'm in the same boat in terms of changing to bugfix-2.0.x. I was hoping you might already be there :)

I'll probably be switching to track that version soon, so I'll test when I do if nobody else gets there first.