When does one shared robot beat a dedicated robot per job in a pick-and-place shop?

What it found

A stdlib extension of osrobot-specialise equips a shop of 2 to 8 pick-and-place trays three ways: a robot per job, one shared gantry spanning all trays, or one shared arm, on capital cost over 200 random job mixes per row. Sharing wins only while the total load fits one machine (4 jobs at scatter 0.4 m: shared cheapest in every mix at demand 0.2 of a gantry per job, a robot per job from 0.3) and only while changeover is short (a robot per job in 99% of mixes at 1,800 s). Trays spread beyond about 0.6 m erode the saving. The shared arm can hold 1 to 2 mm in only 13% of default mixes, but is cheapest in about half of mixes with loose (5 and 10 mm) tolerances. Stylised: every cost, speed, demand and changeover figure is assumed.

A figure from its own output

Paper, code and results

• README and method
• Experiments and results
• Code
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More in Open-source purpose-built robots

• What does a shared pick-and-place robot cost once it has to stay up, and do spares change when sharing beats a robot per job?What does a shared pick-and-place robot cost once it must stay up? Spares priced per job or for every job at once: the shared fleet costs the same fraction of a robot per job when its load fits one machine (0.68 at 4 jobs), and falls to 0.34 to 0.51 when all jobs must run at once. Stylised, assumed availabilities.
• When a spoon-feeding arm meets a moving mouth, what sets the force on the lips: the sensor, the approach speed or a force cap?What sets the force on the lips when a spoon-feeding arm meets a swaying mouth: the sensor, the approach speed or a force cap? Peak force tracks approach speed (1.0 N at 0.05 m/s, 4.0 N at 0.20), a camera cuts how often the lips are touched (0.40 against 0.72 of trials) but not how hard, and latency erodes that gain. Stylised point-mass model, assumed constants.
• Does a spoon-feeding arm need more than two joints? Tip mass, lip force and servo cost of 2 to 6 joint armsDoes a spoon-feeding arm need more than two joints? From 2 to 6 joints the tip mass moves only 0.63 to 0.50 kg and lip force not clearly at all, while servo cost triples (stylised; extends osrobot-assist).
• Does the stylised feeding-arm lip-force result survive real contact physics? osrobot-assist re-run in MuJoCoDoes the stylised feeding-arm lip-force result survive MuJoCo contact physics? The steady push matches KP × LEAD × speed, but the impact peak is 1.84 × higher and the share fed at most 2 N falls from 1.00 to 0.45 at 0.10 m/s (stylised; extends osrobot-assist).
• Is the peak force of a feeding arm on the lips set by the lips' stiffness, the arm's force loop, or its approach lead?Is the peak force of a feeding arm on the lips set by lip stiffness, the force loop or the approach lead? Lip stiffness moves the mean peak from 0.32 to 2.02 N at 0.20 m/s (stylised; extends osrobot-assist).
• If the person being fed judges the spoon better as it nears the mouth, how much of a camera's value does a blind feeding arm get back?If the person being fed judges the spoon better as it nears the mouth, how much of a camera's value does a blind arm get back? A misjudgement shrinking to zero at the lips lifts the blind arm's safe share at 40 mm from 0.47 to 0.84 and restores every feed; stylised, extends osrobot-leannoise.

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Other research topics

Proper scoring & elicitation28Effort & peer prediction9Verification games & slashing19Detection & tolerances14Markets as routers13Prediction-market design9Paying contributors8Decentralised training systems23Digital twins & sim-to-real164LLM chip design loops40Robot manufacturing loops53Ambient AI assistant46Self-replicating manufacturing34Simulation-first design64Engineered clothing45Task-specific AI accelerators40Algorithmic chip-design loops42Open-source purpose-built robots44The software-engineering loop43Adversarial human imitation41Open-source residential construction41Autonomous multi-angle capture34Sensing, imaging and 3D31Energy supply and dense energy storage39Robot societies among people31Agentic co-design of low-cost robots27Laundry-hanging robots25Machine learning on qualitative data23Robots on the building site27Civilizations & group psychology1History & human sciences1

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.