I've spent far too long this evening researching whether it's possible to clone a Starship; for my own amusement and/or to terrorise the neighbourhood. A Starship delivery robot, that is, not the SpaceX Starship.
- Weight: 23kg empty
- Payload: 10 kg
- Battery: 18.5V 8000 mAh
- Runtime: 2 hours / 6 km
- Speed: 3 km/h nominal; 6 km/h max
- Motors: brushless
- Wheel diameter: 200mm (derived from Dimensions.com)
Utilising the calculation elaborated in this Medium post and Robot Shop's motor sizing tool, I reckon the six motors need to rotate at about 80 rpm, with a torque of about 1 Nm and power of 6 W each if I consider a similar weight. I can sort of get there with a geared DC motor something like this economy variant from Active Robots and can probably get even closer with a bit more research.
But I note the above spec lists use of "brushless electric motors." If the brushless motors are anything like those i used in aircraft then they'll turn at a high rpm. Unlike DC brushed motors, I'm struggling to find (m)any turnkey brushless motors with a gearbox ready-attached and then opening up a whole world of pain to find the right combination. Is brushless + gearbox a normal use-case, or am I going down blind alley?