# YAM Task Design & Approach (working doc)

Living doc of how the YAM task/motion pipeline works and the task list. Updated as I go.

## Approach (current)
- **Robot/env:** YAM bimanual (`Template-YAM-Play-v0`, Isaac Lab). Right arm active; left arm frozen (kinematic hold).
- **Planning:** task-space **PRM** (`yam_prm.py`) → collision-free EEF polyline. Task steps are hand-scripted phases (not TAMP).
- **Execution (smooth):** constant-speed **arc-length follower** (`flow()` in `yam_grasp_prm.py`) — the commanded EEF point glides along the whole path from the current pose, so segments blend continuously (no stop-and-go gap). Only stops where the gripper acts (close / release). + integral correction for diff-IK steady-state stall; grasp orientation held fixed (no twist). Adopted from RoboLab's `CartesianIKPlanner`.
- **Grasp:** top-down, close-until-contact (stall detection) + lift by friction (no kinematic attach). Grasp height = table_top + object_height/2 (robust to USD origin). Gripper actuator tuned (damping 60, effort 40) so it clamps.
- **Assets:** **RobotWin (MIT)** GLB → USD via `robotwin_convert.py` (convex-decomposition collision + rigid body baked). Source `/home/horde/xiaotong/robotwin_assets/objects`, USD out `/home/horde/xiaotong/robotwin_assets/usd`. Also license-clean **primitives** (box, cubes, cans) built in-script.

## What grasps reliably
- Uniform cylinders / straight cups / cans (primitive can, RobotWin cup). Grape ~60% (soft cluster). Tapered/glass bottles marginal. Short cubes marginal (stacking needs <2.5cm placement precision → hard).

## Task list
Working (videos in `outputs/tasks/`): grape→box, cup→box, can→box (smooth), sort-2-cubes, RobotWin cup→box (smooth).
Hard/parked: stack cubes (placement precision), glass tumbler (marginal grip).

### Planned — RobotWin assets, distinct from RobotWin's own tasks
(RobotWin already has: beat_block_hammer, place_can_basket, place_object_basket, place_container_plate, place_bread_basket, put_bottles_dustbin, blocks_ranking_*, handover_block …)
| id | task | why distinct |
|----|------|--------------|
| T1 | RobotWin cup → **bowl** (real container) | not a box; different container than RobotWin's plate/basket |
| T2 | RobotWin bottle → **tray** | tray container; bottle object |
| T3 | **hammer → bell** (strike the bell) | RobotWin's hammer task hits a *block*; mine strikes a *bell* |
| T4 | multi-object → basket (cup + block into one basket) | RobotWin places single object; mine batches two |
| T5 | 3-color cube **sort** (extend the working 2-color) | primitive, reliable |

## Delivered (5 task videos, `outputs/tasks/task*.mp4`)
1. **RobotWin cup → box** (real MIT asset, GLB→USD) ✅
2. **DUAL-ARM: two cups picked in parallel** ✅ (both arms, smooth LERP drive)
3. **can → box** with the smooth arc-length executor ✅
4. **sort 2 cubes** into color-matched bins ✅
5. **grape → box** ✅

Reliable objects: cup (RobotWin + straight cups), can, cubes. Hard/failed: hammer & bottle (elongated/tapered → grip slips), RobotWin bowl/tray as containers (curved shapes don't catch the object; primitive box is reliable), cube stacking (placement precision).

## Open problems
- Smoothness done; grasp reliability of soft/short/tapered objects; stacking precision (needs closed-loop/visual servo or a jig).
- cuRobo would give better trajectories but needs a YAM URDF+spheres config (not built).