Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2015 Nov 23;6:2193–2206. doi: 10.3762/bjnano.6.225

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2015, Wagner et al.

This is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (https://www.beilstein-journals.org/bjnano/terms)

PMC Copyright notice

Block diagram of a Kelvin controller based on a) a proportional–integral–differential (PID) controller, and b) the Kalman filter. In the PID controller, the system output is compared to a setpoint to yield the error signal. The output signal, i.e., the sum of amplified errors and their respective integral or derivative, is fed back into the system. When the system output is nullified (setpoint 0), the controller output U_dc equals the surface potential U_lcpd. In contrast, knowing an approximate model of the system, the Kalman filter estimates solely based on the system output and the applied dc bias, U_dc. With the switch S closed, the estimated surface potential is applied as the dc bias, corresponding to a feedback configuration.

Inline graphic — Block diagram of a Kelvin controller based on a) a proportional–integral–differential (PID) controller, and b) the Kalman filter. In the PID controller, the system output is compared to a setpoint to yield the error signal. The output signal, i.e., the sum of amplified errors and their respective integral or derivative, is fed back into the system. When the system output is nullified (setpoint 0), the controller output U_dc equals the surface potential U_lcpd. In contrast, knowing an approximate model of the system, the Kalman filter estimates solely based on the system output and the applied dc bias, U_dc. With the switch S closed, the estimated surface potential is applied as the dc bias, corresponding to a feedback configuration.