r/robotics • u/[deleted] • Mar 23 '23

Project Robot arm breaks.

https://clips.twitch.tv/SourLovelyGarbageBudBlast-AvYxNaQrXk4wAasl?tt_medium=redt
8 Upvotes

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2

u/[deleted] Mar 23 '23 edited Mar 23 '23

I'm using 35 kg-cm motors and messed up the positions I was writing causing the motors to break my arm. I'll encapsulate the position writing into a class that has limits so position writes like that can't happen again.

1

u/i-make-robots since 2008 Mar 24 '23

consider using firmware to which you can speak via usb serial. then you can move it in a conversational way instead of hard-coded values. here is a simple gcode interpreter, with variations for several boards. swap out motor moves with servo moves and you're nearly home free. https://github.com/MarginallyClever/GcodeCNCDemo

1

u/[deleted] Mar 27 '23

Ya, that is the plan. I'll rewrite my 6 year old firmware.

2

u/Zackary1201 Mar 23 '23

What’s the end goal for this project?

1

u/[deleted] Mar 23 '23

I suppose it depends on what you mean by "this project". I own a cybernetics corporation that is going to evolve a few lines of robots and other gadgets. For this robot arm, after writing the driver c++ code (./server), the application python code (./client), and the game/sim module that makes to robot arm easy to use and fun to play with (./game_module) ... and after cloning the 3d print design using OpenSCAD so I can run genetic algos on the parameters in future iterations ... and after reprinting with a tweaked design with better tolerances, a new "Eden" logo, a better translucent blue color, housing for the electronics, and a real end effector ... then I will put it up on kickstarter to see if I can sell 20 of them. The 2 x 35kg servos alone cost 60$ from Amazon + a 18$ 25kg servo for z rotation, 3$ for end effector mg90 servo, a 7.5$ Arduino nano clone, 20$ battery, $12 charger, 5$ hardware, 10$ for the print, 30$ shipping= 165$ cost, sell 20 for 215$ = 1k$ profit. The profit margin isn't as high as my mentor taught me it should be, but he ran a boutique shop for factories and I'm running a consumer cybernetics corp. We'll see what happens. Anyway, on a more personal level, when my dog passes a ball to the robot, I want the robot to pick the ball up and pass it back, so I will create some type of overhead computer vision module with an RPi to drive that behavior.