Technical Issues on Velocity Measurement for Motion Control

Robust motion control requires accurate velocity information. The authors have proposed "synchronous-measurement method (S method)" that measures the velocity synchronous with alteration of pulse numbers. Accurate velocity measurement is achieved in all speed ranges with this method. The method, however, has several technical issues for application in practice: accuracy often deteriorates with nonideality of interpulse angles in optical encoders; and disturbance observer needs modification to deal with nonregular velocity measurement. This paper proposes some solutions for the issues in S method. Experimental results verify the validity of the solutions