Robot payload screening calculator

Static horizontal arm payload from available joint torque, including link self-weight.

robotics-payload.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	payloadkg
	2.89789
	2.21831

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

positive payload capacity2.90 kg✓ passes

BASELINE INPUTS

torque10 N*mreach0.3 mlinkMass1 kggravity9.81 m/s^2

CALCULATED

payload2.8979 kg

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Robot payload screening
# Scope: Static horizontal arm payload from available joint torque, including link self-weight.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

torque = 10 N*m
reach = 0.3 m
linkMass = 1 kg
gravity = 9.81 m/s^2

payload := (torque-linkMass*gravity*reach/2)/(gravity*reach) [kg]

check positive payload capacity: payload >= 1 kg

scenario alternative: torque = 8 N*m

Calculated from your source · not saved

Baseline · Baseline

positive payload capacity2.90 kg ✓ passes

alternative · alternative

positive payload capacity2.22 kg ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

payload: payload = (torque-linkMass*gravity*reach/2)/(gravity*reach) [kg]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

torque: 10 N*m
reach: 0.3 m
link mass: 1 kg
gravity: 9.81 m/s^2

Calculated

payload: 2.89789 kg

Assumptions and limits

Static horizontal arm payload from available joint torque, including link self-weight.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Robot payload screening. Inputs: joint torque limits; geometry; pose; duty. Outputs: conditional payload envelope. Model scope: Rigid links with explicit joints, loads and coordinate frames. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: joint torque limits, geometry, pose, duty
Outputs: conditional payload envelope
Modes: calculate, compare, sweep
Drawing: Robot workspace and trajectory

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS