Cobot joints are small servo systems where brushless motors drive the joints through precision gearboxes, field-oriented control ensures smooth and accurate motion, and encoders feed position readings back to the controller over a differential serial link. Torque measurements or estimates allow cobots to detect collisions, give way when someone pushes on them, and be taught by hand.
Functionalities and devices
| Block | Function | ST devices |
|---|---|---|
| Motor-control MCU | Runs the motor with field-oriented control | STM32G4, STM32C0/C5, STM32H5/H7 |
| Gate driver | Switches the power stage on command | STDRIVE, STSPIN |
| Power stage | Delivers current to the motor windings | STripFET MOSFETs, power GaN, integrated STSPIN/GANSPIN |
| Current and voltage sensing | Closes the torque loop and catches overcurrent | Current-sense amplifiers, op-amps, comparators |
| Encoder interface | Brings position data back to the controller | RS-485 / RS-422 transceivers |
| Encoder line protection | Shields the feedback lines from ESD | 4-line data-line ESD |