The motion differential characteristics estimation using incremental encoders in the CNC feedback loop

Abstract

There is a steady trend in the mechanical engineering industry to increase the required accuracy of parts manufacturing using high-speed equipment. The control of such equipment requires consideration of the motion differential characteristics such as velocity, acceleration, and jerk. However, due to the discrete nature of the incremental encoder operating as a pulse generator, estimation of these characteristics requires the use of special data processing methods. Considered encoder resolution limitations and proposed a method for determining the discreteness providing the maximum possible accuracy of position measurement. Discussed methods of the velocity estimation using incremental encoders. Determined the required sampling frequency of the time counter. The use of CNC-based software and hardware complex for the study of the velocity estimation methods is proposed. Results of experimental investigations confirm the possibility of acceleration estimation and demonstrate problems with jerk estimation. Analysis of the error sources in the measurement of differential characteristics is performed. Topical areas for further research is proposed.