Where you put the meter
Two axes, one shared DC link, one point-to-point motion. Nothing about the physics changes as you move the meter or switch the energy model, but the number does. This is the reason energy claims for robot trajectories are not comparable across papers, and it is why a measurement convention has to fix the plane and the model before it fixes anything else.
The motion
Meter plane
Energy model
Regeneration path
Power flow through the motion
The same motion, measured every way
| Model \ plane | mains | cabinet | DC link | per-axis sum | ratio max/min |
|---|
Each column is one place to put the instrument; compare across a row. Each row is a different definition of "energy" in different units, so the rows are not competing estimates of one quantity and must not be compared to each other: that conflation is itself one of the findings. A published figure is one cell, and nothing requires the author to say which.
Schematic two-axis model: rigid inertia, viscous and Coulomb friction, motor torque constant Kt, winding resistance R, quintic point-to-point profile. Regeneration routing follows the shared-DC-link behaviour disclosed in Fanuc US 8,040,097 (Ebrg = Ebsg − Ebng − RRg) and the chopper-threshold race in Yaskawa JP2005253213A. The ∫|τ| model is the one used in 机器人 43(6):653-663; the I²R dissipation model is Izumi's 散逸エネルギー (JRSJ 15(4), 1997). For intuition, not for mission design: the point is the spread between cells, not any single number.