Study on the observability of double parallel magnetic suspension systems

The observability of parallel suspension is discussed based on mathematical models. The treated parallel suspension systems use a voltage-output power amplifier for energizing the multiple electromagnets. They are classified to series-connected and parallel-connected according to the connection of the coils of the electromagnets. The condition for each system to be observable is presented analytically. The analyses clarify that the condition of observability is same as that of controllability in the series-connected parallel magnetic suspension system with the coil current sensed solely. Such equivalence is also found for the parallel-connected suspension system with the sum of the coil currents sensed.