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Lesson 15 of 21 in this unit

Build AI Systems · ORIGINAL LEARN AI LESSON

Predict several actions at once.

Compare predicted action chunks with fresh-feedback execution.

By the end: Compare predicted action chunks with fresh-feedback execution.

Start with the exampleJump to the experimentRead the explanation
Prerequisites and path options

Why learn this? Compare the work saved by action chunks with the delayed feedback and errors they can introduce.

01 · TRY

Start with something concrete.

Planning three pushes at once can reduce decision calls. A bump after the first push can also make the remaining two commands stale.

Try the interactive model
02 · PREDICT
Before you experiment

Does predicting three actions require executing all three?

Does predicting three actions require executing all three?
03 · EXPERIMENT

Change one thing. Watch what follows.

Loading this browser experiment…

04 · UNDERSTAND
READ & CONNECT

Understand what changed.

Back to the experiment

A shorter explanation, with the original worked examples available below. Both explain the same experiment and its limits.

Same learning goal in both modes: Compare predicted action chunks with fresh-feedback execution.

The question

Planning three pushes at once can reduce decision calls. A bump after the first push can also make the remaining two commands stale.

Try it and inspect what changed

Compare horizons one and three using the same trained weights and displacement.

Inspect the selected receipt immediately after the ninth interval. Compare observedAt between single-step and chunk modes. Count observations and learned-policy calls, then compare full-task success and final error. Keep drag, delay and random offsets matched.

The calculation in words

Six network outputs encode commands at offsets zero, one and two. Targets are consecutive teacher commands, with the last available command repeated at the episode boundary. A horizon of three executes all three outputs; a horizon of one executes only the first and requests another observation. Each command lasts 0.1 seconds.

Keep the conclusion within the evidence

A three-command block spans 0.3 seconds. If a disturbance occurs just after its first command, two later commands can be issued without seeing the changed position. Fewer calls therefore trades feedback frequency against execution work. The model can be frozen throughout; observing again is not retraining.

The interface reports simulated seconds, not real latency or energy. Chunk predictions are learned, but the scheduler choosing how many to execute is programmed. These public comparisons do not establish real-robot timing safety.

You can explore every lesson directly. Completing this page, submitting a project report and demonstrating understanding on a separate case are different records. Optional code is available in the robot-learning studio; it does not increase guided lesson completion requirements.

Open the full worked examples, calculations and limitations

This is the same reference used in Technical mode. Expand it whenever you need the exact numbers, assumptions or further explanation.

Start with the task

Planning three pushes at once can reduce decision calls. A bump after the first push can also make the remaining two commands stale.

Mechanism and units

Six network outputs encode commands at offsets zero, one and two. Targets are consecutive teacher commands, with the last available command repeated at the episode boundary. A horizon of three executes all three outputs; a horizon of one executes only the first and requests another observation. Each command lasts 0.1 seconds.

A three-command block spans 0.3 seconds. If a disturbance occurs just after its first command, two later commands can be issued without seeing the changed position. Fewer calls therefore trades feedback frequency against execution work. The model can be frozen throughout; observing again is not retraining.

Work through the evidence

Inspect the selected receipt immediately after the ninth interval. Compare observedAt between single-step and chunk modes. Count observations and learned-policy calls, then compare full-task success and final error. Keep drag, delay and random offsets matched.

Compare horizons one and three using the same trained weights and displacement.

What this experiment can establish

The interface reports simulated seconds, not real latency or energy. Chunk predictions are learned, but the scheduler choosing how many to execute is programmed. These public comparisons do not establish real-robot timing safety.

Keep collection, fitting, frozen execution and interpretation as separate records. Save the configuration and complete result, including failures, in the robot-learning project. Report submission checks required evidence and text presence; reasoning and implementation quality need independent review.

05 · APPLY
Check your understanding

A three-command chunk lasts 0.1 s per command. A bump follows command one. How many stale commands can remain?

A three-command chunk lasts 0.1 s per command. A bump follows command one. How many stale commands can remain?
06 · CONTINUE

Take this idea with you.

The interface reports simulated seconds, not real latency or energy. Chunk predictions are learned, but the scheduler choosing how many to execute is programmed. These public comparisons do not establish real-robot timing safety.

My Learning
Explore related topics and the topic map

How this topic connects

Explore this topic on the interactive map

Use these connections to review a foundation or choose where to go next. You can open any topic without completing the others.

What it builds on

  • Geometry and control

    Prevent coordinate-frame mistakes when combining robot positions, sensor readings and targets.

You are herePredict several actions at once

Compare predicted action chunks with fresh-feedback execution.

What it enables

  • Robot-learning project Apply in a project

    Combine demonstration provenance, policy comparisons and complete-task evidence in the robot-learning project; keep embodiment limits and review status explicit.

Original Learn AI lesson ·Primary robotics reference