Combined Approach Helping to Reduce Periodic Disturbances in Speed Measuring

Speed measurement counts among ordinary sectional tasks connected with control or monitoring of many industrial processes. Incremental rotary encoders represent widespread devices which, together with corresponding electronics, provide sufficient accuracy and reliability in most cases. Mechanical arrangement of the complete measuring device then determines overall accuracy of the speed measurement. Nevertheless, there exist applications where even a relatively low error of the encoder itself cannot be neglected. Periodic character of related disturbances can help in solving the problem of reduction of their impact on the measurement accuracy. Solution provided in the paper combines two approaches to provide corrected signal. Motivation of the work comes from the field of control of cold rolling mills.