Won Hee Kim Donghoon Shin Chung Choo Chung Microstepping with nonlinear torque modulation for position tracking control in permanent magnet stepper motors. 915-921 2011 CDC/ECC https://doi.org/10.1109/CDC.2011.6161184 conf/cdc/2011 db/conf/cdc/cdc2011.html#KimSC11