Sensorless Position Estimation of a Planar Motor Having Multi Movers

Abstract

　A planar motor with multiple movers has been developed to save the temporary storage space and automate packages loading and unloading in small warehouses. We propose a sensorless position estimation method for the multiple movers with permanent magnets and iron cores using each coil’s inductance under the movers. The inductances are measured in real-time using the current response, and each distance between the coil and the iron core is determined. The position measurement accuracy is evaluated using an experimental planar motor.