Positioning System forSensor less Linear DCMotor

Linearmotorhasgainpopularity aslinear motiondriveinoffice andfactory automation which provides analternative methodtoconventional rotary motor.Chipmounting isoneoflinear motorapplications especially forLinearDC Motor(LDM).Displacement sensorwhichisnormally usedforpositioning onthe system, madethesystem expensive. Thispaperdiscusses theapplication ofsensor lessonpositioning systemfor LDM.A spring isusedtodetermine theposition, while thespring displacement whichisproportional tothe thrust wasproduced bythemotor.Thethrust itself can becontrolled bycontrolling thecurrent supplied tothe motor.Therefore, thepositioning ofLDM canbe controlled byvarying thecurrent value. Theapproach usedinthispaperistocontrol thecurrentisby manipulating various pattern ofPulse WidthModulation (PWM) signal. As a result, thesettling timelessthan 32msfor10mmpositioning hasbeenachieved.