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An optimal algorithm for estimating angular speed using incremental encoders
Un algoritmo óptimo para la aproximación de la velocidad angular utilizando encoders
DOI:
https://doi.org/10.15446/ing.investig.v33n2.39518Keywords:
Fixed-space, fixed-time, incremental encoder, optimal algorithm, estimating speed, truncation error (en)Aproximación de la velocidad, error de truncamiento, espacio fijo, tiempo fijo (es)
This paper proposes a new algorithm using signals from an incremental encoder for estimating a rotating shaft's speed. This algorithm eliminated the oscillations appearing in classical fixed-time and fixed-space algorithms, even when speed was constant. A fixed-time algorithm measures angular displacement at fixed-time intervals, while a fixed-space algorithm measures time every fixed-angular displacement. Time and displacement measurements were used to generate estimations for speed. The new algorithm generated a unique value for estimating speed due to synchronising encoder pulses and a signal formed by impulses every time increase (delta). A first modification of the proposed algorithm was defined, resulting in the harmonic mean between these two proposed alternatives having the smallest relative error possible. This error was always smaller than half the error with fixed-time and fixed-space algorithms. Experimental setup and algorithms are shown, as well as Simulink results using signals acquired from an incremental encoder.
En este artículo se propone un algoritmo nuevo, el cual utiliza las señales provenientes de un encoder incremental para aproximar la velocidad de giro de un eje. Este algoritmo elimina las oscilaciones que aparecen en los algoritmos clásicos, conocidos como a espacio fijo y a tiempo fijo, las que son visibles incluso a velocidad constante. Un algoritmo a tiempo fijo mide desplazamiento angular a intervalos de tiempo fijo, mientras que un algoritmo a espacio fijo mide tiempo a intervalos de espacio fijo. Las medidas de tiempo y desplazamiento se utilizan para estimar la velocidad. El algoritmo nuevo genera una aproximación sin saltos a velocidad constante, dada la sincronización entre los pulsos del encoder y la señal formada a partir de impulsos cada delta de tiempo. Se propone una primera modificación del algoritmo, y el resultado es que el promedio armónico entre las dos propuestas de algoritmo tiene el menor error relativo posible. Ese error siempre es menor que la mitad del error que se produciría con los algoritmos a tiempo fijo o a espacio fijo. Finalmente, se presenta un arreglo experimental para probar los algoritmos, y se muestran los resultados de la ejecución en Simulink, usando señales adquiridas de un encoder incremental.
References
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Copyright (c) 2013 José Danilo Rairán Antolines
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