Comparison to DSHOT control?


(Irie Blue) #1

I’d be curious if we could ever get to this type of buttery smooth control over CAN with the latest firmware , but more importantly just what type of parameters I’d need to tweak, to get to this point. I have been to a couple drone events, where I literally walked up to the operator afterwards and asked, “are you using DSHOT”, to which the answer has been, why yes of course. I’m not a motor control guy, and I don’t even need this level of control, but there is something about how smooth and controlled the handful of drones appear to operate when communicating via DSHOT. I’d be curious to know if this is within the capabilities of the ZUBAX architecture.

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(Pavel Kirienko) #2

One CAN frame at 1 Mbps (the default bit rate for UAVCAN) takes about 145 microseconds to propagate to all nodes, so CAN offers a comparable throughput & latency, higher data integrity guarantees (because of a stronger checksum), and a uniform bus architecture (you don’t need to dedicate a separate interface just for ESC).

Please observe that latencies below approximately 300 microseconds hardly matter, because control loops of the autopilot and motor controllers usually don’t run at higher frequencies, so the delays become insignificant compared to the temporal scale of the control loops.