Duet to move a 3 DOF robot



  • Hi everybody,
    I liked so much the duet with my prusa prnter that I thought it would be a great controller also for my new project: a robot arm.
    I am going to buy just the frame on aliexpress (see attached image). The mechanism is like the famous uArm or Dobot.
    My question is: could I use the Duet in order to move the robot?Is there a firmware somewhere that you know I might use? Or you have some materials to start with?
    Thanks for the reply.
    Luca

    0_1555509335518_China-supplier-high-quality-2-5kg-load (1).jpg


  • administrators

    RepRapFirmware doesn't as standard support the kinematics of that robot arm, but it's relatively easy to add new kinematics to RRF. See https://github.com/dc42/RepRapFirmware/blob/dev/AddingNewKinematics.md. You will need to write the mew kinematics classes yourself, but I can provide advice. The two parts of that robot arm look rather like the proximal and distal arms of a SCARA robot but in a different plane, so it should be possible to copy some of the existing SCARA code.

    Is the arm supplied complete with endstop switches?



  • no, there are not endstops. I have to figure out by myself. But why is that important? I mean, I know the importance of the endstops, but why asking me in this early stage of the project? is there a particular/important reason that I missed?

    Thanks
    Luca



  • I am sorry, the endstops for the 2 arms are under the base of the robot, so I could see them first.


  • administrators

    @lucagirolamo said in Duet to move a 3 DOF robot:

    I am sorry, the endstops for the 2 arms are under the base of the robot, so I could see them first.

    It helps to have endstop switches (homing switches) built in. Without them (or an equivalent, such as absolute encoders on the motors), the firmware can't tell what the position of the arns is at power up. This can be worked around when using linear kinematics, but not easily when using nonlinear kinematics such as provided by that arm.


 

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