A velocity measurement method for acceleration control

An injecting method of physical damping to haptic interfaces based on FPGA

“…It counts the number of pulses n P from the encoder during a fixed sampling period s T and calculates velocity by finite difference derivative. Following equation (3) shows the formulation of M-method [17]:…”

Adaptive High-Performance Velocity Evaluation Based on a High-Resolution Time-to-Digital Converter

“…4. Comparison of the theoretical resolution of our method with four other methods: 1) the M method (simple encoder pulses measurement in a fixed sampling period); 2) the T method (simple period measurement -division of interpulse angle by the pulse interval time); 3) the M/T method; and 4) the S method [4]. the 10-ns range and with 400 ps per channel resolution, the number of usable channels is 25.…”

“…Fig. 4 gives the measurement resolution for the following five methods: 1) the M method (simple encoder pulses measurement in a fixed sampling period); 2) the T method (simple period measurement, i.e., division of interpulse angle by the pulse interval time); 3) the M/T method; 4) the S method described in [4]; 5) our method.…”

“…This is an adaptive method, which results in a greater accuracy at a wide range of velocity measurements rather than the simple CET or double-buffered method. Our method is based on a combination of three previous works: 1) the immediate measurement of encoder pulses and the corresponding time interval that many authors have previously described in the literature [1]- [4]; 2) the adaptive sampling interval method [10], which allows the widening of the measurement range of velocities with a very high accuracy; and 3) the improved method for measuring time intervals with 200-ps resolution and 43-s range [12].…”

“…The elapsed time between two subsequent readouts is managed by the processor, according to previous estimates. In [4], a novel method of velocity measurement for motor drives with optical encoders is proposed. The method, which is called the "synchronous measurement method or the S method," measures the velocity, which is synchronized with the alteration of pulse numbers.…”