Da Vinci Recursive Improvement CAD Harness

Use the exact supplied conservative baseline for initial four-load-case screening, preserving the fixed carriage, pad, and running clearances.

Baseline passes at 523.6 g moving mass. Combined loading controls stress (1.891 MPa in 0–4) and deflection (0.00242 mm); pinch controls buckling (factor 9542 in 1–5). These results support testing a substantially simpler topology.

Test one full-height braced bay: retain nodes 0–3 with edges 0–2, 1–3, 2–3, 0–3 at current sections. Preserve fixed interfaces; recheck all four loads, longer-member buckling, STEP mass and travel clearance before claiming improvement.

Replace the heavy ladder with a 10-mm-deep tapered triangle using 4-mm uprights, 5-mm diagonals and a 3-mm midpoint tie, preserving fixed interfaces pending four-load-case and clearance screening.

Triangle passes at 207.1 g moving mass versus 523.6 g baseline. Combined loading controls: 15.94 MPa in lower upright 0–3, 0.0470 mm tip deflection, and buckling factor 188.9 in lower diagonal 1–4. Clearance is 0.30 mm at all nine travel samples.

Test two unsplit root-to-tip legs: remove tie 3–4 and midpoint nodes; use edges 0–2 (4 mm) and 1–2 (5 mm), retaining 10 mm depth and fixed interfaces. Recheck all four loads, full-length buckling, lateral stiffness, STEP mass and travel clearance.

Use the prior 15.94-MPa combined-load stress margin to replace the tied, split frame with direct 3-mm upright and 4-mm diagonal ribs, preserving fixed interfaces pending four-load-case, full-length buckling and travel screening.

Direct legs pass at 198.45 g, saving only 8.60 g over the tied frame. Combined load controls upright 0–2 stress (20.28 MPa), deflection (0.0616 mm) and diagonal 1–2 buckling (24.08). Clearance stays 0.30 mm at nine samples.

Benchmark a Y graph: retain roots/tip and join both roots at (8,35), with one shared trunk to the tip. Size the trunk for combined bending, not the former upright’s axial role. Compare four loads, buckling, STEP mass and nine-position travel; do not assume savings.

Target lower mass than the 198.45-g passing frame with 3-mm root ribs merging at (8,60) into a 4-mm shared trunk, limiting its new bending span to 10 mm while retaining fixed interfaces pending four-load stress, deflection, buckling and STEP/travel screening.

Y passes screening at 193.52 g, saving 4.93 g but nearly doubling deflection versus prior direct legs. Combined load controls root 0–3 stress (54.39 MPa), tip deflection (0.1196 mm) and diagonal 1–3 buckling (factor 12.16).

Benchmark two direct 3-mm root-to-tip legs at 10-mm depth, removing the junction and shared bending span. Compare mass–stiffness tradeoffs without assuming savings; preserve interfaces and recheck four loads, full-length buckling and STEP/travel.

Replace the Y junction and shared bending span with direct 3-mm root-to-tip ribs to address the prior 54.39-MPa combined-load root stress and benchmark mass against the 193.52-g best design, preserving fixed interfaces pending four-load stress, deflection, buckling and STEP/trave

Direct 3-mm legs pass at 194.56 g, 1.04 g above the Y, but reduce combined-load stress to 22.15 MPa (0–2) and deflection to 0.0714 mm. Combined compression in diagonal 1–2 controls buckling at 10.12; sampled travel clearance remains 0.30 mm.

Test a 6-mm-deep tied triangle: split both 3-mm legs at mid-height and add a 3-mm midpoint tie. Seek mass savings without a shared bending trunk. Preserve interfaces; recheck lateral/combined deflection, effective buckling lengths and STEP/travel.

Replace the direct legs with an all-3-mm Y merging at (10,59), retaining the contract-required 10-mm depth rather than 6 mm and limiting the shared bending rise to 11 mm to target the 193.52-g best while preserving fixed interfaces, pending four-load and travel screening.

Passes at 193.38 g, just 0.14 g below the prior Y. Combined loading controls trunk 3–2 stress (74.77 MPa) and deflection (0.1427 mm); pinch controls diagonal 1–3 buckling (12.89). The tiny saving comes with substantially higher bending stress.

Use the proven direct 3-mm legs as the next baseline: 1.17 g more mass halves deflection and lowers peak stress to 22.15 MPa. Avoid further Y-junction nudges; retain 10-mm depth and require a meaningful load-path change before repeating four-load and CAD travel screening.

Replace the stepped mast, whose combined-load stress reached 77.11 MPa and deflection 0.2463 mm, with two inclined 3-mm root branches feeding a 4-mm shared spine, targeting lower mass than 193.19 g while preserving fixed interfaces pending four-load, buckling and STEP/travel scre

Screening passes but misses the mass target: 193.27 g, up 0.08 g. Combined stress in root 0–3 reaches 79.71/80 MPa. Pinch controls deflection (0.24634/0.25 mm) and diagonal 1–3 buckling (15.73). The inclined Y leaves little stress or stiffness margin.

Remove the shared cantilever: restore direct 3-mm edges 0–2 and 1–2 at 10-mm depth. Prior screening gave 194.56 g, 22.15 MPa and 0.0714 mm—a stronger tradeoff than junction nudges. Preserve interfaces; recheck four loads, full-length buckling and STEP/travel.