A fuel cell system comprises a fuel cell including an anode and cathode, a fuel reformer, and a water gas shift reactor. The end effectors include fiber optic light transmission sensors for determining various wafer surface, edge, thickness, tilt, and location parameters. A lead compensator determines a compensated command to compensate for an admittance function of the load. A push restriction unit restricts pushing of the knob that has been rotated from the base position.