Arm Motor Controller

[pablo-collantes]

Things that we currently believe to be on our arm.

Quick overall summary of the discussion:

First Joint - Nema 17 connected to worm gear

Second and third Joints - DC motors with encoders also most likely connected to a gearbox (Motors could be CIMS or our RC brushed motors)

End effector / claw - single 35 kg servo

All motors, servos, and encoders will have to go back to a teensy that will handle the state of the arm.
PCB needs DC motor controllers, Stepper controller, and inputs for encoders, pwm of motors and servo, and input for stepper.

More Detailed Explanation:

The main layout is to place a worm gear on the base joint. worm gear part
It is 600 dollars but were applying to igus to hopefully get it free. We would also then use this worm gear with one of their nema 17 motor kits motor kit
So this combo would be our first joint making sure the arm can go up and down from the base and where most of the weight of our payload and arm would be supported by.

The next joints have been talked about to simply be more brushed dc motors, whether they will be our cims like the ones on our drivetrain or our old rc brushed motors or even just completely new dc motors is still up in the air.
Each dc motor however will have to be connected with an encoder so the encoder info will have to go back to our teensy so we can calculate the arms current position.

For our end effector or claw I know it can be designed with a single servo in mind. Most designed typically use a worm gear between two gears and this allows both sides of the claw to work together. Here's a design that i found that does this. claw

And finally all of these motors and servos should be controlled by a teensy, When we create a PCB for it would need to have to have our DC motor controllers, a stepper controller (which we have), and it would need to connect everything to it and print the state of each motor so that it can be sent to our ROS nodes.