PD arm interface checks
For the arm.local interface supplied for this PD. Each teacher uses their own arm and assigned control device.
Practice before the check
Everyone operates their own arm. In the individual run, take five minutes to set up, fifteen to practice both endpoints with help, ten to try again and measure, and five to explain the result. Keep your written measurements. The facilitator checks actions live during PD or a follow-up. No filming is required.
Before the cohort arrives
- Label each arm, control device, and matching wi-fi network. Join that arm’s network and open its arm.local interface. Keep printed references or a second device for internet access.
- Confirm the physical reference pose before recalibrating. The interface asks the operator to center the arm at 90 degrees, which by its own field conventions (J₁ = θ₁, J₂ = signed θ₂ + 90°) puts both links straight out in one line at 12 o’clock. Nothing on screen reports whether the arm actually reached that pose, so check it by eye on the hardware.
- Test the installed arm and interface together. Verify a known target and measure the result. Replace or repair any arm that cannot operate consistently. Keep one front demonstration arm as a spare.
What the supplied interface establishes
| Control | Meaning in degrees |
|---|
| Shoulder field | The calculated shoulder angle. The displayed range is 20° to 150°. |
| Elbow field | The signed joint angle plus 90°. The displayed range is −70° to 250°. |
| SEND TO HOME | Requests 90° in both displayed joint fields. This is not an instruction to enter zero in both fields. |
| Target coordinates and GO | The interface calculates the joint angles and applies the field conversion. |
During a teacher’s demonstration
- Clear the workspace and confirm the assigned connection, degrees, cm, and link lengths of 18 cm and 22 cm.
- For a manual elbow-up solve, make the calculated bend negative, then add 90°. A bend of 144.4° gives −144.4° + 90° = −54.4°. Enter the shoulder angle as calculated.
- For FK, run the committed angles and measure the landing. For IK, verify the hand solve with FK first, then operate the two targets and measure both. A successful GO run does not prove a separate hand solve.
- If the arm misses, check the calculation, units, connection, calibration, and measurement. Use the approved hardware procedure if recalibration is needed.
Before signing the physical criterion, the facilitator must verify the teacher’s operation and measurements live during PD or the follow-up. Peer notes alone do not establish readiness. A simulation cannot replace the physical check.
Interface behavior checked against the supplied arm-local.html on September 8, 2026. No physical arm or firmware was tested in that source review. The cohort lead must verify calibration and the physical reference pose on the installed hardware before PD.