Probe Actuation Feedback Control for Trajectory Accuracy
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Solution Overview
Problem
Conventional scanning probe microscope control systems are limited in their ability to precisely control the position and angle of the probe over time, particularly in following complex trajectories and maintaining accuracy and speed during scanning processes.
Innovation Solution
A probe actuation system that measures the position or angle of the probe using detection signals and adjusts illumination to drive the probe along predetermined trajectories, incorporating feedback control mechanisms that vary the desired value over time to achieve precise control, enabling the probe to move along complex paths such as raster scans or Lissajous curves with constant or varying speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional feedback control systems are used to control probe height, then the system can maintain basic stability, but the probe cannot follow complex trajectories with precise speed control
Solution Approach 1:
The patent applies dynamics by making the desired value time-varying to enable the probe to follow complex trajectories with predetermined speed profiles. The feedback controller receives a desired value that changes over time, allowing the system to dynamically adjust probe position along predetermined paths such as raster scan patterns or Lissajous curves while maintaining constant or varying speed as required
Solution Approach 2:
The patent employs feedback control by continuously comparing the actual probe position (measured by the detection system) with the desired time-varying position and adjusting the piezo actuator accordingly. This closed-loop feedback mechanism ensures that the probe follows the predetermined trajectory with high accuracy while maintaining the desired scanning speed
2Productivity
If the probe moves quickly across the sample surface, then scanning productivity increases, but measurement precision and trajectory following accuracy deteriorate
Solution Approach 1:
The feedback controller continuously monitors the probe position through the detection system and compares it with the desired time-varying position, generating error signals that drive the piezo actuator to correct any deviations. This real-time feedback ensures high measurement precision even at increased scanning speeds
Solution Approach 2:
The system uses dynamic desired value profiles that are optimized for the specific trajectory and speed requirements. By carefully designing the time-varying desired position signals, the system can maintain measurement accuracy while achieving higher productivity through faster scanning speeds
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the speed and accuracy of the scanning process by allowing the probe to follow precise trajectories, improving interaction with the sample surface and enabling more detailed topographical measurements or material property analysis.
Implementation Method 1
the angle of the probe is measured by an optical sensor which generates a detection signal
Implementation Method 2
the height of the probe is controlled by a piezo actuator
Data Source
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AI summary
A probe actuation system has a detection system arranged to measure a position or angle of a probe to generate a detection signal. An illumination system is arranged to illuminate the probe. Varying the illumination of the probe causes the probe to deform which in turn causes the detection signal to vary. A probe controller is arranged to generate a desired value which varies with time. A feedback controller is arranged to vary the illumination of the probe according to the detection signal and the desired value so that the detection signal is driven towards the desired value. The probe controller receives as its inputs a detection signal and a desired value, but unlike conventional feedback systems this desired value varies with time. Such a time-varying desired value enables the probe to be driven so that it follows a trajectory with a predetermined speed. A position or angle of the probe is measured to generate the detection signal and the desired value represents a desired position or angle of the probe.