Does an arm-wait-aware printer demand fix queueing analysis of a robot-printer cell?
research/robofab-cell-stall
Does adding the arm's queueing delay (a fixed point, no fitted parameter) to the held printer's demand fix MVA of the robot-printer cell? No: it underpredicts in all 32 settings and is worse overall (7.9% mean error against 6.2% for held-demand and 4.7% for plain MVA). Negative result. Stylised.
What it found
A follow-up to the held-printer project: the printer’s demand is increased by the arm’s queueing delay, found as a fixed point from the arm’s own queue with no fitted parameter. Against the simulated cell (cv 0.3 and 1.0, 4–16 printers, four loads, 20 seeds, 32 settings; illustrative times) it underpredicts throughput in every setting and is worse overall: mean absolute error 7.9%, against 6.2% for held-demand MVA and 4.7% for plain MVA. At saturation it ties held demand (3.1% against 2.9%) but on the other 24 settings it is worse (9.5% against 7.3%). A negative result: a demand-side patch to product-form MVA is the wrong tool here. Stylised and simulation-only.
A figure from its own output
Paper, code and results
More in Robot manufacturing loops
- Can a blocking-aware correction to queueing analysis predict a robot-printer cell across loads?Can a blocking-aware correction to MVA predict the held-printer robot cell across loads? A fitted stall helps only at saturation (1.4% error) and worsens other loads (8.5%); keeping latency apart from capacity gives 3.6% against plain MVA's 4.7% on the design grid, but only ties plain MVA (3.4% against 3.5%) on a held-out job mix. Stylised.
- Can a parallel-jaw arm assemble its own gripper?Can a parallel-jaw arm assemble its own toy gripper? A complete order exists only once the jaw opens to the widest part (30 mm); a top-down-only arm accepts 120 of 720 orderings against 384 with sideways moves; pad thickness changes nothing (negative). Stylised boxes.
- Can a printed gripper assemble its own next generation?Can a printed gripper assemble its own next generation? With fixed-size jaw pads a gripper builds a copy only at scale ≥ pad thickness in mm (4 mm pads: scale 4); a stroke cap of S mm needs 30·pad ≤ S; seeds of 130 and 140 mm sustain a chain, 60 and 100 mm decay. Largely algebraic given an assumed opening; stylised.
- How long an arm does it take to assemble its own toy gripper?How long an arm does it take to assemble its own toy gripper? A planar two-link arm needs 60–140 mm links as the tray moves 40–400 mm away, and a 90° elbow limit more than doubles it (stylised).
- Does the assembly order change the arm an arm needs to build its own gripper?Does the assembly order change the arm needed to build its own gripper? Across all 384 valid orders the shortest arm is identical in every setting tried (negative result, stylised).
- Can friction hold each printed part of a gripper?Can friction hold each printed part of the toy gripper? The simulated minimum jaw force matches the m·g/(2μ) bound to within 5% over 33 cases and is at most 0.1 N, so the jaw opening, not friction, is the constraint (stylised).
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Produced with AI assistance (Claude). Results are from the code in this repository and are simulated or stylised unless the abstract says otherwise; nothing here implies affiliation with or endorsement by any lab, researcher or company cited. MIT licensed.