Levitation-guidance stabilization of superconducting maglev through LSM currents
This paper presents a modeling and simulation of a superconducting maglev vehicle with a levitation and guidance assist method we have proposed. The assist system stabilizes and assists the vehicle operation so that the vehicle does not need to depend on the mechanical wheels as much as possible at low speeds. By controlling the LSM armature currents, the auxiliary levitation and guidance forces are provided. The results show that the assist system produces appropriate levitation and guidance forces, establishing the reference levitation height and a sufficient guidance at low speeds even against the disturbance force of lateral wind.
Robust uncertainty compensation in MagLev by using extended state observer
The magnetic levitation (MagLev) system control is one of the most complex problems due to open-loop instability, nonlinear dynamics and uncertain parameters. The 3rd order differential model of MagLev is linearized by using input-output linearization. The control law is designed using feedback linearization (FL) augmented by uncertainty estimates. The states and uncertainties are estimated using extended state observer (ESO). This paper addresses the issue of robustification of FL control law against the uncertainty and nonlinear perturbation by using ESO. The stability of overall system is assured and is dependent on the pole placement. The results demonstrate the efficacy of extended state observer for estimating wide range of uncertainty in a highly nonlinear plant, when maximum information of MagLev system is unknown.
Outputs of Plural Tin Oxide Gas Sensors for Compound Gaseous Indoor-Air Pollutants
Output patterns of four types of tin oxide gas sensors for compound gaseous indoor air-pollutants are investigated. The sensor patterns prefer higher gas-sensitivity characteristics when there is a compound gaseous pollutant including two kinds of gases. After the experimental system detects a lower gas-sensitivity pattern in a residence, it can detect a higher one. The reverse is impossible. Three NDVs (NDVA, NDVC, NDVN) characteristics are also adopted to increase the reliability of the system. NDVA characterisitic decreases for a few minutes and gets back to an original state or under the state when an alcoholic gas generates. The system can identify whether the alcoholic gas is generating or not in an indoor environment by using NDV characteristics with high reliability.