Robot morphology × learned control

LACE–CRAFT

Robot Co-Design with Actor Inheritance and Blackboard Collaboration

Continue learning on the current robot.
Adapt what it has learned to new designs.

Hardware-adapted prototype 8× playback
The hardware-adapted robot walking indoors with its arm removed
Generated geometry. Physical motion.12 leg joints

Yuhan Wen1,2 · Jiawei Wang1,3 · Qixuan Zhang1,2 · Yusen Qin4 · Lan Xu1,2,*

1 Deemos Corporation2 ShanghaiTech University3 University of Cambridge4 D-Robotics

* Corresponding author: Lan Xu

The idea

A new body need not
start from scratch.

Robot co-design changes both the body and its training reward. LACE–CRAFT preserves useful control experience while testing those changes: LACE trains and selects candidates; CRAFT proposes and cross-reviews morphology–reward pairs.

01

Reuse learned control

Continue from the full training state, or copy actor parameters and observation statistics into a new design.

02

Review body and reward together

Four specialist roles share experimental records, develop proposals, and cross-review their interaction.

03

Select, record, repeat

Compare trained candidates with the retained incumbent using a fixed task metric, then update the shared record.

Inside the framework

Two training routes.
One shared design process.

01 / METHOD

Carry experience into the next round.

Both routes begin with the same best robot so far. Continuation restores the full learner state on the unchanged body and reward. New designs inherit actor parameters and observation statistics, with other learner components initialized anew.

  1. Continue trainingSame body and reward · restored training state
  2. Adapt new designsProposed bodies and rewards · inherited actor
  3. Compare candidatesEqual additional training budget per branch · retained incumbent

See the process

From the first checkpoint
to the next robot.

02 / DEMONSTRATION

Narrated demonstration · 2 min 44 sec · 1080p · Real-world walking shown at 8× speed Download video ↓

Five locomotion tasks

Evaluating the selected policies.

03 / RESULTS

Across the five tasks, LACE–CRAFT's mean task score is 6.4–91.9% higher than the reproduced D2C baseline under the reported budgets.

Each fixed policy is evaluated with three seeds and 128 episodes per seed. Both searches generate 30 new designs; LACE–CRAFT additionally runs four continuation training units.

Ant

Task score · mean ± sample standard deviation across evaluation seeds

All results and ablations
Final-policy evaluation scores
TaskDefaultD2CNo Actor inheritanceNo replay evidenceLACE–CRAFT

D2C's final selected morphology–reward pair is retrained once before these evaluations. Evaluation-seed variability is distinct from variability across independent training runs or complete searches.

Beyond parameterized bodies

From shape reference
to an articulated robot.

04 / HARDWARE

Generated meshes become editable links, configured joints, motor interfaces, and simulation assets. Hardware adaptation turns the geometry into printable parts and a walking prototype.

Built, assembled,
and tested in motion.

The assembled robot includes an SO-101 arm. Because of the current hardware constraints, the indoor walking demonstration uses the hardware-adapted 12-leg-joint robot with its arm removed.

The geometry-stage model and the hardware-adapted controller are described separately in the paper.

See assembly and walking

LACE–CRAFT

Reuse control.
Revisit the design.

Robot Co-Design with Actor Inheritance
and Blackboard Collaboration

Watch the demonstration

Figure