Robotics / Digital twin / Check against prediction

Digital twin · prediction check

Overload against Reach and hold

Observed run

Prediction

• base: position is 0.040 rad rms off the prediction
• base: current is 612% off the prediction (1.138 A rms)
• base: winding peaks 38.6 C above the prediction
• shoulder: position strays 1.356 rad from the prediction, past the 0.1 rad fault limit
• shoulder: position is 0.701 rad rms off the prediction
• shoulder: current is 486% off the prediction (4.352 A rms)
• shoulder: winding peaks 63.8 C above the prediction
• elbow: position strays 0.978 rad from the prediction, past the 0.1 rad fault limit
• elbow: position is 0.429 rad rms off the prediction
• elbow: current is 598% off the prediction (1.731 A rms)
• elbow: winding peaks 58.8 C above the prediction
• wrist: position strays 0.567 rad from the prediction, past the 0.1 rad fault limit
• wrist: position is 0.070 rad rms off the prediction
• wrist: current is 1130% off the prediction (1.024 A rms)
• wrist: winding peaks 32.2 C above the prediction

Both runs are simulations: the observed run stands in for a real joint until a device posts one with source device:<id>.

The observed run carries 3 kg on tool; the prediction carries nothing held.

The observed scenario is "min-jerk reach and hold, payload past the shoulder's peak torque" and the prediction's is "min-jerk reach and hold".

Observed

Printed arm, stand test fault

Prediction

Printed arm, stand test ok

Rules

command within 0.01 rad rms; position watch 0.02 rad rms, fault 0.1 rad max; current watch 25%; winding watch 5 °C, fault 15 °C

Joints