High-Resolution Absolute Position Vernier Shaft Encoder Suitable for High-Performance PMSM Servo Drives

Abstract

Abstract-Permanent magnet synchronous motor (PMSM) drives are suitable for high-performance servo applications, as in robotics. This, however, requires an accurate position feedback, which is not possible with the existing absolute position encoders, unless one is prepared to compromise on the size of the encoder. This paper proposes a new encoding scheme based on the simple Vernier principle. The proposed scheme improves the resolution of the encoder within limited disk diameter. An improved encoder based on the same principle is also presented with minor modifications to improve the resolution. Computer simulations and experimental work have shown that a suitable modification of the Vernier concept can result in an encoder that is superior to the existing ones. Details of this work are presented.

Two‐degree‐of‐freedom proportional integral speed control of electrical drives with Kalman‐filter‐based speed estimation

“…where E(•) is expectation, V(•) is variance and || || ∞ is infinite norm. As can be seen from (11), in the backward differentiation method, the mean value of noise is zero, and its variance and infinite norm depend on m. Increasing m suppresses the noise, but it also enlarges the measurement window length, causing a larger time delay. When incremental encoder and enhanced quadrature encoder pulse unit are used, the noise can be suppressed by setting a high sampling frequency and no excessive time delay is caused.…”

“…On high‐performance servo occasions, absolute optical encoders are often used to acquire rotor position information. Compared with the incremental optical encoders, absolute optical encoders have great advantages in rotor positioning [11]. However, its speed measurement performance is not as good as the former.…”

Medición del sentido de giro, velocidad y posición angular de un eje mediante encoders

“…En este trabajo se utiliza un encoder absoluto, con el fin de comparar y ajustar el comportamiento del incremental, dado que el absoluto entrega lecturas de posición angular de manera precisa. Al respecto la literatura es extensa, y por ejemplo hay trabajos en donde se utiliza el encoder absoluto y se busca incrementar su resolución, como en [15]. Esto, porque aunque entregan una medida con precisión, su resolución es baja, en caso contrario son costosos; por ejemplo, el que se utiliza en este artículo tiene pasos de 45°.…”

Dual-Gap Dual-Pole Composite Machine for Mechanical Rotor Position Estimation

“…is demanding higher compactness and robustness from electric drive units [1]. Different from common speed and torque control systems where the electrical rotor position is sufficient for Field Oriented Control (FOC), high performance motion control requires the mechanical rotor position (also known as absolute rotor position) of servo motor as the indispensable feedback for position closed loop [2][3][4]. The relationship between electrical rotor position θe and mechanical rotor position θm follow…”