I follow a forum called On-Step where similar technology is used to point telescopes at specific parts of the sky and follow the apparent motion of the stars for astrophotography.
The same issues arise. Gears have backlash, except for harmonic drives. Belts and pulleys have zero backlash and are the favoured method of gearing up a small stepper motor to provide sufficient torque. Or just to link the drive to the driven 1:1.? Harmonic drives are ace but kinda spendy for most of us. There are a couple of builds in the gallery that use them.
Technology from 3D printers is heavily leaned on in the form of various supported motor drivers. Mostly of the silent stepper stick variety. They have a fair bit of intelligence built in and can change the way they drive the motor to optimise it's use for a given task. Microstep control features quite a lot in this. The TMC2130 is well used and the TMC5160 or the S109 can handle more current. The TMC2209 shows promise but the clone makers haven't settled out a standard format yet.? 3D printers are also often used to print parts and cases.
Cheap microcontrollers are used to run the On-Step software. There is a range of options with varying cost and capabilities. The ESP32 is well favoured at the moment. Good bang for little bucks.
The software to run it all is written by the group founder with help from others and feedback and testing from all users. It uses GitHub as a repository for development of the open source code.
The purpose of this snapshot of another group is not to advertise that group but to suggest that as a development model it has worked very well to achieve a similar goal with similar tech. I'm sure some of what they use would be helpful here. You have a lot in common.
They have the same intelligent, rational approach and discussion that happens here. Like minds. I think that develops in these groups because you can't blag a machine.
Ant?
