Automated control of an actively compensated Langmuir probe system using simulated annealing

A simulated annealing (SA) method has been developed to deduce 14 Fourier terms in a radio frequency waveform for active compensation of a Langmuir probe system. The active compensation system uses seven harmonics to generate a required waveform. Therefore, 14 heavily interacting continuous parameters need to be tuned before measurements can be taken. Because of the magnitude of the resulting search space, it is virtually impossible to test all possible solutions within an acceptable time. An automated control system employing SA has been developed for online tuning of the waveform. This control system has been shown to find better solutions in less time than skilled human operators. The results are also more reproducible and hence more reliable.