Compiled Firmware with 5bar-Scara / Dual-Arm-Scara

Enpixa

Hello DC42,

thats what i already did, see my latest post/config: https://forum.duet3d.com/topic/13631/compiled-firmware-with-5bar-scara-dual-arm-scara/18

@Enpixa said in Compiled Firmware with 5bar-Scara / Dual-Arm-Scara:

M574 X2 S1 P"xstop" ; X min active high endstop switch
M574 Y2 S1 P"ystop" ; Y min active high endstop switch
;M574 Z1 S0 P"zstop" ; Z min active high endstop switch

I tried all thinkable variations ( active low/high / trigger min/max )

Right now, i dont know what more i could try to make it work.

JoergS5

@Enpixa I don't have more ideas. I would try a last test inverting with the ! sign *), then trying other endstop hardware.

*)
P"pin_name" Defines the pin name(s) that the endstop(s) for the specified axis are connected to. Needed when S=1. May need ! before pin name to invert signal. in https://duet3d.dozuki.com/Wiki/Gcode#Section_M574_RepRapFirmware_Num_3

Enpixa

Is the red LED on the mainboard a good indicator if it is working properly hardware-wise ? Because when
i press the endstop manually the LED is on. if not pressed it is off.

If you have a recommendation for me which endstops i should buy. i would appreciate it.

JoergS5

@Enpixa i've read "The second line (S1) defines all
active high endstops.

If you are unsure if your endstops
are active high or active low, you
can test them by observing the
light next to the corresponding
stepper motor connector. If the
light is lit when the button is
pressed, then this would indicate
an active low endstop"
in https://dozuki-guide-pdfs.s3.amazonaws.com/pdf/duet3d/guide_10_en.pdf page 11. So the light tells you the type of endstop. If it is the light you mean, then it would be a active low endstop.

JoergS5

@Enpixa which type of endstop recommendation: for your current printer setup the endstop would be sufficient imho which you use. An alternative would be an optical endstop.

I want to go another direction with an optical encoder like described in https://github.com/JoergS5/OpticalEncoder

Enpixa

Hello Jörg,

thx for that information, for my understanding i got an active low endstop. LED next to stepper plug is lit when endstop is pressed.

Video of pressing Endstop: http://nörds.de/video_2020-03-05_14-04-43_1.mp4

This is the direction setting used in my Config

M569 P0 S1 ; Drive 0 (X) goes forwards
M569 P1 S1 ; Drive 1 (Y) goes forwards
M569 P2 S1 ; Drive 2 (Z) goes forwards
M569 P3 S1 ; Drive 3 (E0) goes forwards

That Information i found for setting the endstops

The electrical type of the endstop (S parameter). This used to be just active high (S1, e.g. a normally-closed switch or opto switch), or active low (S0, e.g. normally-open switch or Hall sensor). There are now also options for using a Z probe (S2) and for using motor stall detection (S3).

These are the X, Y and Z parameters. 0 means no endstop present, 1 means an endstop switch at the minimum end, 2 means an endstop switch at the maximum end of the axis.

As the Arm is moving towards me and the Endstop when using positive X-Values i set X and Y to 2 for maximum checking. (G1 S2 X20 F100 makes the arm moving in direction to the endstop)

M574 X2 S0 P"xstop" ; X max active low endstop switch
M574 Y2 S0 P"ystop" ; Y max active low endstop switch
;M574 Z1 S0 P"zstop" ; Z min active high endstop switch

I just set an Axis-Limit
; Axis Limits
M208 X-300 Y-300 Z0 S1 ; Set axis minima
M208 X300 Y300 Z300 S0 ; Set axis maxima

Best, Johannes

bondus

Cool! Another 5-bar.

By putting the proximal inner joints on top of each other you actually have a 4-bar, the 5'th has zero length. I hope the math in the code works, it is a special case.
One effect of that is that most of the work modes no longer work, you will always be in work mode 2. Assuming your proximal arms have the same length.

Your case with all arms the same length and inner joints in the same place is actually a much simpler case than what the current implementation can handle, but it should work fine.

I think your homing move is not right, you should use the H1 option to G1.

My homing file "home5barscara.g":

G91              ; relative positioning

G1 H1 Z300 F1500 ; move quickly to endstop and stop there (first pass)
G1 H2 Z-5 F900      ; go back a few mm
G1 H1  Z300 F90  ; move slowly to endstop once more (second pass)

G1 H1 X300 Y300  F2500 ; move quickly to endstop and stop there (first pass)
G1 H1 X300 F2500
G1 H1 Y300 F2500
G1 H2 X-2 Y-2 F900      ; go back a few degrees
G1 H1 X300 F90  ; move slowly to endstop once more (second pass)
G1 H1 Y300 F90  ; move slowly to endstop once more (second pass)

G0 Z-2  ; move down a bit to not make mesh calibration move it out of machine limits
G90              ; absolute positioning

G0 X0 Y0 F6000 ; move to a reasonable position

You would have to remove z-homing and make X (or is it Y?) move towards negative instead. I have my right arm homing switch in between the arm joints.

I think your steps/mm, G92, is wrong. It should be steps/deg in this case.
Assuming you have 200step/rev steppers. it should be 71.1111111111.
200 steps/rev * 128microstepping / 360degrees = 71.1111....
With the steppers directly attached to the arms you should be able to move stupendously fast but with pretty poor precision.

dc42

@Enpixa said in Compiled Firmware with 5bar-Scara / Dual-Arm-Scara:

Is the red LED on the mainboard a good indicator if it is working properly hardware-wise ? Because when
i press the endstop manually the LED is on. if not pressed it is off.

That's as expected for a normally-open switch; however normally-closed switches are preferred (which reverses the sense). The LED is a reliable indicator when the endstop is a simple microswitch. It isn't always reliable if the endstop is an optical switch.

Enpixa

@bondus

Hi Bondus, thx for your feedback. Yes, in future i will use some kind of gears. For the very first protoype
i wanted the Software/Firmware getting working... later on alle the fine-tuning, rigid mechanics etc.

********* UPDATE **********
I found this important info in the doku.

Endstop type S0 (active low switch) is no longer supported in M574 commands. Instead, use type S1 and invert the input by prefixing the pin name with '!'. Ex: M574 X1 S1 P"!xstop" I think Jörg also mentioned it somewhere before.

Now is see pressing the X-Endstop with M119 !

Endstops - X: at max stop, Y: not stopped, Z: not stopped, Z probe: at min stop

Yeeehaa ! Thx alot, Video of first time homing:

http://nörds.de/first_time_homing.mp4

Best, Johannes

Enpixa

How can i tell the Firmware that there is no Z-Endstop and homing for it is not needed:
i tried to set M574 Z0 or removed that Line from config.

G28 Error: G0/G1: insufficient axes homed
The following axis is not homed: Z

bondus

@Enpixa Use G92 Z0

Enpixa

Hello Jörg, Bondus and DC,

thx for your input. As you suggested i built a small transmission for the steppers. Had to wait for the GT2 belts till today and printed some Gear-Pulleys.

Left Arm on Image is X and right Arm Y.

Working Mode 2, Distance of Rods 70mm, Length of arms 260.5mm and the Degree Defintion of Endstops 128/38

This is the most relevant Line in the config.g:

M669 K9 L2 X0:70 Y0:0 P260.5:260.5 D260.5:260.5 B128:38

Is this as it is meant with the forward direction ? (Also tried for X-arm M569 P0 S0 )
M569 P0 S1 ; Drive 0 (X) goes forwards
M569 P1 S1 ; Drive 1 (Y) goes forwards
M569 P2 S1 ; Drive 2 (Z) goes forwards
M569 P3 S1 ; Drive 3 (E0) goes forwards

Homing seems to work fine First it moves X arm zu Endstop, then Y arm to Endstop.

home5barscara.g

G91 ; relative positioning

G1 H1 X-120 F2000 ; move quickly to endstop and stop there (first pass)
G1 H1 Y120 F2000 ; move quickly to endstop and stop there (first pass)

G92 X60
G92 Y60
G92 Z0
G90; abs pos

When trying to drawing a square everything seemes to be rotated by 45° and all Lines are very Curvy (and its not really a square, but that comes later, i hope):

Drawing Square Test ( See Cyan Color on Image )
G90
G1 H1 X0 Y0 F2000
G1 H1 X0 Y60 F2000
G1 H1 X60 Y60 F2000
G1 H1 X60 Y0 F2000
G1 H1 X0 Y0 F2000

Any idea what i am doing wrong with the machine-setup/ config ?

Thx in advance, Johannes

JoergS5

This post is deleted!

bondus

@Enpixa That "square" looks like the firmware still thinks it is a cartesian printer.

Run your M669 command from config.g on the console to make sure there are not errors.

Edit: Looks like the firmware requires 4 parameters to the "D" option, that's not intended. That's a bug. Just add some 0's and it should be fine.

bondus

@Enpixa said in Compiled Firmware with 5bar-Scara / Dual-Arm-Scara:

Drawing Square Test ( See Cyan Color on Image )
G90
G1 H1 X0 Y0 F2000
G1 H1 X0 Y60 F2000
G1 H1 X60 Y60 F2000
G1 H1 X60 Y0 F2000
G1 H1 X0 Y0 F2000

And if you use H1 in the G1 command you will move a specific motor, it will not use the kinematics. Remove the H1s:

G90
G1 X0 Y0 F2000
G1 X0 Y60 F2000
G1 X60 Y60 F2000
G1 X60 Y0 F2000
G1 X0 Y0 F2000

Edit: One more thing, you might want to change the Y parameters to M669 as well. As it is set up now Y 0 is on the arm joints where you pullys are. If you set it to negative about the distance to where your work area is your 0,0 coordinate will be on the work area.
For example: M669 .... X-35:35 Y-300:-300 ... will make X0 in the middle between the joints and Y0 300mm in front of the joints.

Enpixa

Hello Bondus,

thx a lot for your great inputs again ! About the construction: Right now this is really only a functional test-model
for making first tests with the software / firmware. Mechanical stuff will come later. At the moment i want to be able
to quickly replace some parts. remove 1-2 screws, put it in a different place for testing etc. Atm i dont even have a Z.
I definetly will consider your suggestions when it comes to the next steps with the machanics. The rigidy should be fine
for the first testing. ( At least i can repeat my "square" 10x and it is drawing always the same lines in the same place )
Yesterday for example i still had smaller Pulleys and replaced them quickliy with larger ones.

But now to my testing

M669 K9 L2 X-35:35 Y0:0 P260.5:260.5 D260.5:260.5 B128:38
Wrong number of values after '''D''', expected 4 (as you wrote)
M669 K9 L2 X-35:35 Y0:0 P260.5:260.5 D260.5:260.5:0:0 B128:38
Gives no Feedback, seems to be ok

First thing i always do is the homing-process. After that:

When running a simple G1 X1 or G1 X-1 it tells me
Error: G0/G1: target position not reachable from current position

Even after Homing (G28) it tells me
G28 Error: G0/G1: target position not reachable from current position

also tried to define the Printarea with Z Parameter
M669 K9 L2 X0:70 Y0:0 P260.5:260.5 D260.5:260.5:0:0 Z0:0:500:500 B128:38
same result.

Is there a parameter for deactivating Position-Checking for the testing-phase.
Or am i missing more Parameters which needs to be defined.

Also tried different G92 Positions after G28 (G92 X60Y60) as starting point etc.

bondus

@Enpixa My first prototypes were far worse than yours

I would guess it has to do with Y coordinate limits. After a homing it should be somewhere around X27 Y400. If you changes the Y argument as I suggest you should get a more reasonable Y.

I'm not sure if you can run without limit checks, but set them to something crazy should work fine, go large negative too. The kinematics will always check the limits of the various joints, but the defaults should be very allowing.
You could try to set the arm joint limits in M669. I run A10:170:0:360:0:360 C-90:270:-90:270 right now. But be careful and be ready to stop it

Check the M208 limits in config.g too.

Enpixa

i am going crazy. i am not sure if it is just my stupidness or the firmware or the bad construction.

For being sure i loosened the screws a little bit that there is no friction ( want to be sure not to loose steps to the cost of being not that precise)

Homing went fine... G92 X0Y-250 After that G91 for relative positioning and then i go stepwise G1 Y+10 which creates that green line (can do it till i reach Y-30 then it tells me out of drawing area).... ok , its not perfect straight... but kind of At 3 random points on the Y-Line I do several times G1 X+10 till endstop and several times G1 X-10 till endstop. This creates my pink lines and look like parabolas.

When moving it looks like there is no loss of steps or friction.

Any idea why this is happening ? Is it bad configuration, bad hardware or maybe a failure in math fo firmware ?
I think as there is a trinsmission now that 71.1 steps / mm is too low now, could this cause this behavior ?

I also attached my config.g
config.g

Best,
Johannes

dc42

@Enpixa said in Compiled Firmware with 5bar-Scara / Dual-Arm-Scara:

Is it bad configuration, bad hardware or maybe a failure in math fo firmware ?
I think as there is a trinsmission now that 71.1 steps / mm is too low now, could this cause this behavior ?

If the firmware is know to work on another machine, then most likely bad calibration and/or incorrect steps/degree IMO.

JoergS5

@Enpixa I checked your config, I don't see an error.

Please tell me your stepper types (200 or 400 steps), pulley and big wheel teeth count, I'll setup the same configuration like you and process your tests.