Latte art is a complex task requiring dexterity and precision, making it a challenging and commercially relevant task. A one-shot learning system is employed in which a single barista demonstration is segmented into five functionally distinct phases, each encoded as an independent Cartesian Dynamic Movement Primitive (CDMP) with its own parameters. Against a single-CDMP baseline, per-phase encoding reduces transition endpoint error by 3.2-4.5 times and art-stroke shape error by 2.7 times, reproducing jug tilt to below 1 degree RMS in the pouring phases. The learnt pour scales from a 280mL to a 400mL cup through a single spatial offset and a scaled recipe, with no re-demonstration. The phase-based CDMP approach generalises beyond latte art to any demonstration task whose phases have distinct spatial or temporal requirements whilst demonstrating the ability to adapt reproductions to suit different task requirements.
Figures & tables
Figure 1: Robot pour in motion with highlight results
#
Phase
Type
1
base_to_mix
transition
2
mixing
pouring
3
mix_to_art
transition
4
art
pouring
5
return_base
transition
Table 1: Phase decomposition of a latte art demonstration
Figure 2: Phase decomposition shown across each layer. Each column is one phase; rows show the human demonstration, the learnt primitives, and the robot reproduction.
280ml
400ml
Espresso dose
21g (single)
42g (double)
Milk volume
250ml
350ml
Rim diameter
80mm
90mm
Table 2: Beverage parameters for the two cup sizes.
Phase
αs
K
ρ
τ
base_to_mix
7.0
500
5.0
1.0
mixing
7.0
800
10.0
1.0
mix_to_art
7.0
700
6.0
4.0
art
7.0
800
8.0
1.0
return_base
7.0
500
5.0
1.0
Table 3: Per-phase CDMP parameters: temporal scaling τ , basis-function density ρ , stiffness K ( D=2K ).
Figure 3: Top-down trajectories of the mix_to_art transition for (a) the one-shot and (b) the phased reproduction, showing the human demonstration, the CDMP rollout and the executed robot motion.
Phase Evaluation Metric
Tilt RMS ( \SIUnitSymbolDegree )
Height RMS ( mm )
Phase
Type
Metric
E1
E2
×
Unit
E1
E2
E1
E2
base_to_mix
transition
endpoint error
30.1
9.5
3.2
mm
5.05
1.03
22.1
6.3
mix_to_art
transition
endpoint error
14.9
3.3
4.5
mm
9.51
0.61
60.8
18.7
return_base
transition
endpoint error
38.3
11.9
3.2
mm
9.35
3.54
40.7
12.4
mixing
pouring
coverage ratio
1.18
1.17
1.0
—
4.35
0.88
18.0
15.9
art
pouring
shape RMS
6.35
2.38
2.7
mm
3.15
0.75
11.3
16.5
Table 4: Per-phase comparison of one-shot (E1) and phased (E2) reproduction against the human demonstration. Phases are grouped by type. × denotes the improvement factor E1/E2; lower is better except for coverage ratio, where 1.00 is ideal.
Figure 4: Jug tilt relative to ground plane over the art phase for (a) the one-shot and (b) the phased reproduction.
Figure 5: Top-down photographs of the produced latte art. E1 is omitted as it was not poured with milk (Section 5.3 ).
During steady pouring, images and robot pose may remain nearly unchanged while transferred mass accumulates, making the return decision ambiguous for a whole-task vision-language-action (VLA) policy. We present FlowVLA, which separates motor generation from physical-completion estimation. A shared π0.5 action expert learns approach, pour, and return with boundary-aware supervision. A target-independent estimator fuses visual, joint, wrist-wrench, and recurrent force-belief histories to maintain an estimate of transferred mass. The controller initiates return when this estimate plus predicted residual outflow reaches the requested mass. In coffee-pot/water experiments, FlowVLA achieves 13.1 g goal-balanced mean absolute error (MacroMAE), lower than all tested VLA baselines. Across all attempts, 53.7% both complete the task and finish within +/-10% of the requested mass. The same model interpolates to held-out 150/250-g targets without retraining. Independently trained models further evaluate the formulation in three additional container-fluid settings.
Liwen Yang, Yutian Zhang, Jiaqi Zhai +10
Zhejiang University · DEEP Robotics · Shanghai Artificial Intelligence Laboratory +2
Learning from Demonstration (LfD) enables robots to learn complex behaviors from expert examples, yet existing approaches often fail to generalize to new compositions of known skills without retraining. Modern generative policies model distributions over action trajectories alone, thus are unable to reason about the symbolic outcomes required for robust composition. We propose that skills should jointly model action trajectories and the symbolic outcomes they induce. To address this gap, we introduce Predicate Action Skills (PACTS), a class of closed-loop visuomotor policies that model skills as a joint generative process over action and predicate belief trajectories, producing coherent action-outcome rollouts within a single model. Jointly generating actions and predicates enables PACTS to learn internal representations that improve both action generation and predicate classification. Furthermore, we demonstrate zero-shot composition of learned skills via planning by leveraging online predicate predictions from PACTS as a symbolic interface for sequencing and monitoring execution. Project website: https://planpacts.github.io/
Robotic reproduction of oil paintings using soft brushes and pigments requires force-sensitive control of deformable tools, prediction of brushstroke effects, and multi-step stroke planning, often without human step-by-step demonstrations or faithful simulators. Given only a sequence of target oil painting images, can a robot infer and execute the stroke trajectories, forces, and colors needed to reproduce it? We present IMPASTO, a robotic oil-painting system that integrates learned pixel dynamics models with model-based planning. The dynamics models predict canvas updates from image observations and parameterized stroke actions; a receding-horizon model predictive control optimizer then plans trajectories and forces, while a force-sensitive controller executes strokes on a 7-DoF robot arm. IMPASTO integrates low-level force control, learned dynamics models, and high-level closed-loop planning, learns solely from robot self-play, and approximates human artists' single-stroke datasets and multi-stroke artworks, outperforming baselines in reproduction accuracy. Project website: https://impasto-robopainting.github.io/
Yingke Wang, Hao Li, Yifeng Zhu +6
Stanford University. · The University of Texas at Austin. · University of California, Berkeley. +1