AFM Raster-Scan Imaging: Constant-Force Topography Feedback

This simulator turns the single-point AFM force-curve physics into a real raster-scan imaging instrument: a PI feedback loop drives the cantilever's piezo command to hold a constant tip–sample contact force while the tip sweeps line by line across a genuine 2D sample topography with a spatially varying, stickier "material" patch. The recorded piezo-command trace builds up into a reconstructed height image in real time, exactly the way a real constant-force AFM works — and switching to open-loop constant-height imaging reproduces the real distortion artifact that closed-loop feedback exists to fix, driven by the same damped-oscillator and DMT contact equations rather than a scripted image.