Adaptive velocity‐dependent proportional‐integral controller for high‐speed atomic force microscopy

摘要: High-speed atomic force microscopy (AFM) has been rapidly developed in recent years. To reduce the oscillation of scanner, a single-tone sinusoidal wave is widely used as scanning rather than triangular high-speed AFM. However, nonlinear, resulting nonconstant relative linear velocity between sample and tip while x-direction. If traditional proportional-integral controller still feedback z-direction, control errors will be enormous. Therefore, paper proposes new adaptive velocity-dependent controller. The relationship parameters achieved by fitting experimental results. controllers are compared against each other some examples. experiments demonstrate that decreases z-direction to half, which provides more precise AFM images. LAY DESCRIPTION: Typically, scanner follows waveform fast axis (x-axis), very slow ramp signal (y-axis) conventional This mode can called raster scan. contains high-order Fourier harmonics, vibrating distorting image easily. In AFM, effect harmonics severe. above problems solved replacing waves with waveform. sinusoidal-raster scan nonraster based on microscopy. nonlinearly path cause variable tip. standard Z direction, large, this difference evident at scanning. Thus, solve problem. Experiments show obtained using about half without it. These illustrate proposed method improve quality both low high speeds.