Manipulation in Clutter

(aka "Bin Picking")

Part 1

MIT 6.800/6.843:

Robotic Manipulation

Fall 2021, Lecture 8

Follow live at https://slides.com/d/flsZtLY/live

(or later at https://slides.com/russtedrake/fall21-lec08)

Course Roadmap

1. Hardware basics (iiwa + WSG)
2. Basic pick and place
   • Kinematics / Jacobian-based control
   • Moved a single object assuming we knew its pose
3. Geometric perception
   • Pose estimation from depth for a single known object

Probability distributions over environments.  Work by Greg Izatt

How do you generate random kitchens?

"Clutter clearing" (an early project at TRI)

YCB Benchmarks – Object and Model Set

Richer contact geometries

The cartoon from walking is not rich enough for manipulation...

Rich collision geometries

Green arrow is the force on the red box due to the overlap with the blue box.

"Point contact" as implemented in Drake

"Point contact" as implemented in Drake

Multi-point contact

Many heuristics for using multiple points...

"Hydroelastic contact" as implemented in Drake

"Hydroelastic contact" as implemented in Drake

Red box is rigid, blue box is soft.

"Hydroelastic contact" as implemented in Drake

Both boxes are soft.

Point contact vs hydroelastic

Point contact (discontinuous)

Hydroelastic

(continuous)

vs

Hydroelastic is

• more expensive than point contact
• (much) less expensive than finite-element models

State-space (for simulation, planning, control) is the original rigid-body state.

"Hydroelastic contact" as implemented in Drake

Point contact and multi-point contact can produce qualitatively wrong behavior.

Hydroelastic often resolves it.

Point contact vs hydroelastic

Example: Simulating LEGO® block mating

Manually-curated point contacts

Hydroelastic contact surfaces

Stable and symmetrical hydroelastic forces

Before

Now

Text

The corner cases

Point contact

the frictionless case

The corner cases

Point contact (no friction)

Hydroelastic

(no friction)