Bill of Materials

A photo of our shop, with a chicken on the workbench.

Configurations

The robot can be built with a DIY frame and four corner assemblies, or as a complete robot with aluminum frame.

Complete Robot

Solar Panels x 4
Chassis Wiring - data
Chassis Wiring - power
Corner Assemblies x4
Super Capacitors
Motherboard Assembly
GPS Modules x 2 (Source) GPS Antennas x 2 (Source) Frame Side x 2
Frame Front x 2
Frame solar panel mounts

Corner Assembly

Motor controller PCB assembly with UI PCB
$100
Induction encoder PCB
$20

Aluminum fork upper weldment
Aluminum fork lower weldment
Thrust bearings
3D printed steel steering drive gear
Drive motor phase and hall cable
Steering motor phase cable
Induction encoder interface cable

Drive Motor

Supplier URL
$275.00
This motor is generally pretty good, but it may not be weatherproof enough. May need to order a custom motor, but suppliers we have contacted have not wanted to make a motor with the high gear ratio reduction of this wheelbarrow motor. Bafang requires a 500 piece order to custom make a motor. It may be possible to convince Bafang that the world needs a robust electric farm robot wheel which supports larger diameter tires, better weather sealing, and planetary gearing. Or someone on the ground in China may be able to find a manufacturer which can support our needs. So far efforts to do so over Alibaba have failed.

Tires

Carlisle X Trac ATV Bias Tire - 4.80-8 $40
Amazon link

Steering Motor

AM Equipment AMP240-0502
Supplier URL
$300 - We no longer need the built-in encoder, so a cheaper weather sealed motor should be found, or a non-sealed motor plus enclosure should be tested.

Something in the 60 RPM range similar to these $45 aliexpress motors could be viable:
Aliexpress URL
Warning these shippers seem slow and unreliable. A reliable supplier would need to be found, if testing showed the motors to be of acceptable performance. These motors may be under powered - needs testing.