Can a FOC control scheme be done using a rotary encoder to measure the position, speed and acceleration directly, or is measuring current necessary?
FOC is a motor control scheme as described in links below:
Quote from the second link:
Field Oriented Control is one of the methods used in variable frequency drives or variable speed drives to control the torque (and thus the speed) of three-phase AC electric motors by controlling the current. With FOC, the torque and the flux can be controlled independently. FOC provides faster dynamic response than is required for applications like washing machines. There is no torque ripple and smoother, accurate motor control can be achieved at low and high speeds using FOC.