AFFORD-BENCH · PHYSICAL CONTACT ROBUSTNESS

Do robot manipulation policies comply
when contacts shift?

Selim Sarowar1, Physical Superintelligence Research Team1,2 1Yeungnam University  ·  2Physical Superintelligence

AFFORD-Bench measures whether robot policies adapt under mid-trajectory physical contact disturbances without causing dangerous contact force spikes (F > 150 N) or motor torque saturation. Every Dynamic rollout is counterfactually matched to a Base nominal control sharing identical scene setup, seeds, and executed prefix a0:t*.

AFFORD-Bench counterfactual matched prefix replay protocol comparing Base nominal rollouts with Dynamic rollouts measuring actuator torques and contact force spikes
01

the physical evaluation gap

Same past. Shifted physical contact.

Base and Dynamic share the identical executed prefix a0:t*, isolating the outcome effect of exogenous contact disturbances.

STATIC BENCHMARKS (LIBERO, ROBOMIMIC, LIBERO-PLUS)

The scene shift is visible before action begins.

shift reset→observe→act

Static benchmarks test generalization from shifted initial poses. Crucially, they lack actuator motor torques and contact force sensors—leaving violent collisions, jamming, and motor stalls completely invisible.

AFFORD-BENCH PHYSICAL DYNAMIC ROBUSTNESS

Physical contacts shift after the arm commits.

reset s₀→replay a0:t*→shift Δx at t*→sense & comply

Measures Compliant Dynamic Success: Ssafe = Sdyn ∧ (Fmax ≤ 150 N) ∧ (|τj| ≤ τmax,j). Evaluates whether policies absorb disturbances or cause catastrophic contact damage.

Competitive Advantage over LIBERO-MAX: Motor Torques & Force Safety

In vision-only benchmarks like LIBERO-MAX, a policy that rams a peg into a fixture at 300 N or stalls its motors is scored as a "success" as long as the end effector eventually triggers the completion box. AFFORD-Bench logs full 7-DoF Franka actuator motor torques (τact) and robot-scene contact force wrenches (Fcontact) at 20 Hz. Over 78% of kinematic "successes" in open-loop or position-controlled models are classified as physical safety violations.

Domain 1: Industrial Precision Shaft Assembly — Evaluating compliant insertion under 0.5 mm peg-hole tolerance and 150 N force boundary. Logged: τact [7], Fcontact [1]

the physical taxonomy

Eight Ways Contacts & Workpieces Shift

Frozen across 960 matched evaluation pairs

Target displacement animation
GEOMETRY · 01

Target Displacement

Workpiece displaced ±3 cm along ±x, ±y, or ±xy mid-approach, requiring visual-tactile re-acquisition.

Fixture shift animation
GEOMETRY · 02

Fixture & Goal Shift

The insertion hole or receptacle shifts during transit, testing whether insertion adapts dynamically.

Impact force spike animation
FORCE · 03

Impact Force Spikes

Monitors external contact wrenches against the ISO/TS 15066 safety bound (Fmax ≤ 150 N).

Torque saturation animation
TORQUE · 04

Motor Torque Saturation

Checks joint motor torque limits [87, 87, 87, 87, 12, 12, 12] N·m to detect actuator stall.

Bayonet lock animation
MECHANICAL · 05

Bayonet & Twist Locks

Non-reversible mechanical locking requiring continuous downward threshold press before twist unlock.

Spring resistance animation
MECHANICAL · 06

Compliant Spring Counter-Force

Spring-loaded doors and caps exhibiting nonlinear opposing torque during turning and opening.

Nonprehensile push animation
CONTACT · 07

Non-Prehensile Push & Grasp

Thin plates pushed over table overhang edges before fingers can establish a stable pinch grasp.

Obstacle snag animation
PATH · 08

Obstacle Snag & Jamming

Sudden clearance snags during peg and pin insertion causing part jamming and high friction.

02

benchmark construction

240 Tasks Spanning 8 Contact Domains.

From 210 core tasks across D1–D7 to 30 frontier reactive tasks in D8, frozen into 960 deterministic evaluation pairs.

Feature Comparison: AFFORD-Bench vs. Contemporary Manipulation Benchmarks
Benchmark Tasks Dynamic Mid-Task Shift Actuator Torques (τact) Contact Force (Fcontact) Force Limit Check (150 N) Frozen Manifests
AFFORD-Bench (Ours) 240 ✓ Paired Prefix (960 pairs) ✓ 7-DoF Motor Torques ✓ Real-Time Wrench ✓ Compliant Ssafe ✓ Full + Lite
LIBERO-MAX (2026) 130 ✓ Paired Prefix ✗ None (pixels only) ✗ None ✗ None ✓ Full + Lite
robomimic (2021) 7 ✗ Static reset only ✗ None ✗ None ✗ None ✗ Ad-hoc
LIBERO-PRO (2024) 100 ✗ Static OOD reset ✗ None ✗ None ✗ None ✗ None
03

experimental findings

Contact Shifts Break Kinematic Success.

Four policy families evaluated on 960 matched pairs using released inference parameters.

56.2%

of nominal Base successes fail under dynamic contact shift.
Furthermore, 78.4% of surviving kinematic rollouts violate physical safety limits—causing severe part jamming, torque saturation (>87 N·m), or exceeding the 150 N human-robot collaborative force ceiling.

Base vs. Dynamic vs. Safe Compliant Success Rates across robot policies
The Compliance Gap: Position-controlled VLAs and Diffusion Policies achieve non-zero kinematic completion by pushing through collisions, but drop dramatically when compliance (Fmax ≤ 150 N, τ ≤ τlim) is required.
Benchmark Leaderboard across 960 Matched Pairs (Full Track)
Policy Base Rate (%) Dynamic Rate (%) Drop (pp) Compliant Safe Ssafe (%) Peak Force Fmax (N) Torque Saturation
Compliant Closed-Loop Oracle 95.2[93.8, 96.5] 91.4[89.6, 93.1] -3.8 88.1[86.0, 90.1] 32.4 ± 6.2 2.1%
Diffusion Policy (Vision-State) 74.1[71.3, 76.8] 38.3[35.2, 41.4] -35.8 15.2[12.9, 17.6] 248.5 ± 34.1 46.8%
Diffusion Policy (State-Only) 79.3[76.7, 81.8] 42.1[38.9, 45.2] -37.2 18.4[15.9, 21.0] 214.2 ± 28.5 39.2%
BC-RNN (Vision-State) 62.4[59.3, 65.4] 21.2[18.6, 23.9] -41.2 8.3[6.6, 10.2] 284.1 ± 42.0 58.4%
BC-MLP (State-Only) 68.0[65.0, 70.9] 24.5[21.8, 27.3] -43.5 9.1[7.3, 11.1] 276.9 ± 38.2 54.2%
Open-Loop Replay 97.4[96.3, 98.4] 3.1[2.0, 4.3] -94.3 1.2[0.6, 2.0] 310.8 ± 45.0 82.6%

Italics indicate 95% bootstrap confidence intervals over 960 evaluation pairs. Compliant Safe Success requires Ssafe = Sdyn ∧ (Fmax ≤ 150 N) ∧ (|τj| ≤ τmax,j).

04

open benchmark

Validate first.
Evaluate next.

Every benchmark manifest, schema specification, evaluation launcher, and torque channel validator is fully reproducible.

# 1. Clone repository & install
$ git clone https://github.com/Physical-Super-Intelligence/AFFORD_Bench.git
$ cd AFFORD_Bench
$ pip install -e .

# 2. Validate frozen benchmark manifests
$ python scripts/validate_manifests.py

# 3. Run matched paired evaluation (Lite track: 96 pairs)
$ python scripts/evaluate_paired_dynamic.py \
    --manifest benchmark/lite/afford_bench_lite.json \
    --out results/paired_lite.json
05

citation

Cite AFFORD-Bench.

If you use AFFORD-Bench or its torque/force channels in your research, please cite our RSS 2027 paper. Download BibTeX.

BIBTEX · AFFORD-BENCH 2027
@article{sarowar2026affordbench,
  title       = {AFFORD-Bench: A Benchmark for Physical Affordance, Compliance, and Reactive Contact Robustness in Robot Manipulation},
  author      = {Sarowar, Selim and Physical Superintelligence Research Team},
  institution = {Yeungnam University},
  journal     = {Robotics: Science and Systems (RSS)},
  year        = {2027},
  url         = {https://github.com/Physical-Super-Intelligence/AFFORD_Bench}
}