159. SOURCE SEEKING WITH VERY SLOW OR DRIFTING SENSORS
Name: Nima Ghods
Grad Year: 2010
Slow sensors arise in many applications, including sensing chemical concentrations in tracking of contaminant plumes. Slow sensors are often the cause of poor performance and a potential cause of instability. In this poster we present a modified extremum seeking scheme to account for and exploit slow sensor dynamics. We also consider the worst case, which is sensor dynamics governed by a pure integrator. We develop a design for source seeking in a plane using a fully actuated vehicle, prove its closed-loop convergence, and present simulation results. We use metal-oxide microhotplate gas sensors as a real world example of slow sensor dynamics, model the sensor based on experimental data, and employ the identified sensor model in our source seeking simulations. Metal oxidebased microhotplate gas sensors have become popular because of their small size, high sensitivity, low power consumption, and compatibility with semiconductor manufacturing technology. Here we modify extremum seeking to account for the dynamics of slow sensors and apply it to tuning the position of the sensor to find the position with the maxim gas concentration (i.e. the point where the nonlinear map output is maximized). As the first step of proof of concept we pervade the local stability proof of the scheme via averaging and show some numerical results.