Wheel odometry and error calculator

Differential-drive short-interval body displacement; no slip or pose integration.

robotics-odometry.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	distancem	headingrad
	0.11	0.0666667
	0.1	0.133333

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.

heading increment budget3.82 deg✓ passes

BASELINE INPUTS

left0.1 mright0.12 mtrack0.3 m

CALCULATED

distance0.11 m

heading0.066667 rad

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Wheel odometry and error
# Scope: Differential-drive short-interval body displacement; no slip or pose integration.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

left = 0.1 m
right = 0.12 m
track = 0.3 m

distance := (left+right)/2 [m]
heading := (right-left)/track [rad]

check heading increment budget: abs(heading) <= 10 deg

scenario alternative: left = 0.08 m

Calculated from your source · not saved

Baseline · Baseline

heading increment budget3.82 deg ✓ passes

alternative · alternative

heading increment budget7.64 deg ✓ 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.

distance: distance = (left+right)/2 [m]
heading: heading = (right-left)/track [rad]

Original worked example

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

Given

left: 0.1 m
right: 0.12 m
track: 0.3 m

Calculated

distance: 0.11 m
heading: 0.0666667 rad

Assumptions and limits

Differential-drive short-interval body displacement; no slip or pose integration.

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: Wheel odometry and error. Inputs: wheel counts; track width; wheel diameters. Outputs: pose increment; sensitivity to wheel mismatch. 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: wheel counts, track width, wheel diameters
Outputs: pose increment, sensitivity to wheel mismatch
Modes: calculate, compare, sweep
Drawing: Robot workspace and trajectory

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