Senior design project quadruped robot built under $1000 using rewound BLDC motors, capstan drives, and cheap FOC controllers.
Key Takeaways
Target BOM under $1000 and under 20 lbs achieved by replacing $250/actuator hardware with $59 TYI 5008 motor + MKS XDrive Mini combos.
TYI 5008 motors rewound from 335 KV to 90 KV (22 AWG delta to 24 AWG star, 40 turns/slot) tripling stall torque from 0.421 Nm to 1.274 Nm.
XDrive Mini CAN bus communication only works reliably with native/custom firmware; ODrive open-source firmware caused random disconnects regardless of tuning.
Capstan drive joint (9.6:1, 12 Nm peak, 120 deg ROM) costs ~$80 using 1mm Mastrant-M Dyneema DM20 rope with prestretching to reduce slack.
