Higher Bandwidth Tracking

Adaptive XY control takes advantage of a Bruker-proprietary control technology “Model Based Inverted Iterative Control” to achieve a tracking accuracy (e.g., peak error) of less than 1% of the total scan range in a minimum amount of time. This inversion-based iterative control (IIC) is based on the work of Q. Zou et al., “Precision tracking of driving wave forms for inertial reaction devices,” Rev. Sci. Instrum. 76, 023701 (2005).Zou et. al.

After a user specifies a new Scan Size, Scan Rate or Scan Angle, the Adaptive XY algorithm automatically generates and optimizes a scan table. The scan table ensures high bandwidth tracking without introducing sensor noise.

For conventional PID (proportional, integral, derivative) closed-loop XY control, the tracking bandwidth is well below scanner's resonant frequency in the X and Y directions.

With Adaptive XY control, the tracking bandwidth can be even higher than the scanner's resonant frequency. Tens of Hertz can be achieved without compromising image quality:

Figure 1: Scan taken with Adaptive XY Control Disabled. The periodic artifact is a product of XY scanner ringing.

Figure 2: Scan taken with Adaptive XY Control Enabled. The ringing seen in figure 1 is absent.

Figure 3: Adaptive XY 8 nm square Scan of Mica Showing Atomic Resolution (Left, Height data; Right, Height Sensor Data)

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