[Drew Rogge]

Here’s my STEPS_PER_MM section from the defaults/defaults_generic.h file:

; ;// In here we are interpreting MM as degrees of rotation

; #define STEPS_PER_DEGREE(motor_steps, micro_steps, reduction)

; ; ; ; ((motor_steps * micro_steps * reduction) / 360.0)

; #define DEFAULT_A_STEPS_PER_MM STEPS_PER_DEGREE(200., 32., 5.)

; #define DEFAULT_B_STEPS_PER_MM STEPS_PER_DEGREE((200.*(5+2./11.)), 32., 5.)

; #define DEFAULT_C_STEPS_PER_MM STEPS_PER_DEGREE((200.*(5+2./11.)), 32., 5.)

; #define DEFAULT_D_STEPS_PER_MM STEPS_PER_DEGREE((200.*(5+2./11.)), 32., 77./13.5)

; #define DEFAULT_E_STEPS_PER_MM STEPS_PER_DEGREE(200., 32, 2.)

; #define DEFAULT_F_STEPS_PER_MM STEPS_PER_DEGREE(200., 32, 2.)

; #define DEFAULT_G_STEPS_PER_MM STEPS_PER_DEGREE(200., 32, 2.)

It takes into account the gear reduction in the axis, the steps per revolution of the motor and the micro steps setting of the driver. Currently all my motor drivers are set to 32 microsteps per step.

[Drew Rogge]

There’s another gripper in Danny Van Den Heuvel’s Hackaday project. It’s in the ;STL_V2.02.zip ;file. I’m not sure but I think it’s based on the one from the Mantis Robot Arm.

[Drew Rogge]

It could be that you don’t have the current set right on that axis’ driver but I think a lot of people are using a 2 amp stepper like the one ;here ;instead of the 0.4 amp referenced in the BOM.

[Drew Rogge]

Hi Angel,

I’ve finally able to drive at least two axis of my Thor arm with Asgard and that brings up the question of where in Asgard or your version of GRBL to you take into account the different microstep settings and the gear reduction of the various articulations? I know that Art1 needs a 5x increase, art2 is 5x + 5.18x for the gear motors. In the defaults_generic.h file all axis are set to a value of 250 for DEFAULT_?_STEPS_PER_MM.
Just wondering if I’m missing something.
Thanks for all your good work,Drew

[Drew Rogge]

Jesse, i had some of AngelLM’s ControlPCBs made at Seeed Studios and have some spares. I can sell you one for $15.00 including shipping in the US.
Drew

[Drew Rogge]

Please do, Angel! Glad to contribute any way I can.

[Drew Rogge]

I’ve attached an image from a Fusion 360 project. The idea is that the head of the 3mm socket head cap screw pushes on the inside of the Art2 body when it’s unscrewed and presses the roller into the belt.

[Drew Rogge]

I feel that I should also point out that using Sepio’s Art3LowerBody will also require using his entire Art3 design. Not sure is it affects Art4 and above.

[Drew Rogge]

Art1 is 5 to 1.Art2 is 5 to 1 plus a 5.18 to reduction for the gear motor.For Art3 I’m using a 77/13.5 to 1 reduction for the gt2 belt plus 5.18 reduction for the gear motor.Art4 is 2 to 1.
Haven’t figured out reductions for Art5 and 6 yet.
Drew

[Drew Rogge]

Andrea, There’s a user named Sepio that’s done a lot of redesign of Art3 through Art56. His project log on this page:
https://hackaday.io/project/26341-building-and-improving-the-thor-robot-arm/log/70087-day-18-redesign-of-art3-and-art4
contains a Art3LowerBody with a fan added to it.
Drew

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