The reality → model direction: paste your measurements and PolySim fits a validated model, with R² and residuals — then hands the identified plant to controller design.
Model Fit & ValidateLive
fit a model to your real measured data
Controls
Paste your measurements (x,y per line) and identify a validated model — with R², residuals, and a handoff to controller design.
Reading this result: Strong fit (R² = 0.988): this model explains your data well. You've identified the plant — send the K/τ to Controller → Code to tune a PID for your real system.
Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.
★ Sign in to save this setupSave your tuned setup, or drop this simulation into your own site, docs, or course page.
How it works
Model Fit & Validate closes the loop back from reality to simulation. Paste real measured data (x,y per line — for example a step-response you logged from a motor or heater through the Hardware Bridge) and fit a model: linear, exponential, first-order step (K, τ — system identification), logistic, or power. It reports the identified parameters, R², and RMSE so you know whether the model actually captures your system. When you fit a first-order step, it also suggests IMC-tuned PID gains and links straight to Controller → Code — so you can measure a real system, identify its model, design a controller for it, and flash the code. Uses Gauss–Newton (with Levenberg damping) least-squares fitting, entirely in your browser.
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Ask the AI about this model
The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.
Is this fit model to data system identification tool really free?▾
Yes. Model Fit & Validate runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?▾
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.