Resolver compatible capacitive rotary position sensor

Abstract

This paper describes a capacitive rotary position sensor that is characterized by its high compatibility with commercial resolvers. The main components are two electrode plates. Both parts are composed of simple circular or annular electrodes. The sensor is excited by two sinusoidal voltages, which are same as the excitation voltages of resolvers. These excitation voltages are applied to the stator transmitting electrodes. Then, these voltages arise on rotor electrodes by capacitive couplings. The stator pick-up electrodes detect voltages on the rotor that are amplitude-modulated due to the capacitance changes depending on the rotor position. The specifications of these signals are same as those of resolvers. Therefore, the rotor position can be calculated by the same way as resolvers. Due to the similarities with resolvers (excitation signals, generated signals and the way of calculate positions), this sensor can easily replace a commercial resolver. In this paper, the principle is verified by a prototype sensor, which shows a non-linearity error of +/-4 degrees.

Random Rotary Position Sensor Based on Fiber Bragg Gratings

“…The methods above mentioned cannot have the function of detecting a rotor to be rotated at the same direction infinitely. Although several Manuscript 360-degree rotation position sensors based on electrical and electromagnetic mechanisms and devices, such as resolvers [6], magnetoresistance elements (MRE) [7], [8] and capacitive sensing elements [9], [10], have been proposed, they are actually not immune to electromagnetic interference and ground loop as compared with the optical-fiber structured sensors. For improving these disadvantages to be practically applied in meteorological anemoscope, ship's rudder indicator, airfoil control, and other relevant servomechanisms, the rotary position sensors should have capability to detect the rotating angle of a rotor which is rotated infinitively at arbitrary direction.…”

Kapasitif Enkoderler için Sağlam bir Algılayıcı Mekaniği

“…Zheng ve arkadaşları, herhangi bir yazılımsal hata minimizasyonu algoritması kullanmadan algılayıcı mekaniklerinde yaptıkları iyileştirmelerle enkoderin doğrusal olmama hatasını indirgemişlerdir [7]. Kapasitif enkoder çıkış sinyalindeki hataların benzer şekilde algılayıcı mekanikleri üzerinden giderildiği buna benzer bir kaç çalışma daha bulunmaktadır [8,9]. Bu çalışmaların tamamı sağlam bir algılayıcı mekaniğin kapasitif enkoderler için ne kadar önemli bir bileşen olduğunu gösteren değerli çalışmalardır.…”

Periodic Nonlinear Error Analysis and Compensation of a Single-Excited Petal-Shaped Capacitive Encoder to Achieve High-Accuracy Measurement

“…The encoders are classified as optical, magnetic, inductive, and capacitive according to their measurement principle. Optical and magnetic encoders are dominant in the market as they can achieve high precision, but they tend to be relatively expensive and bulky [2,6,7,8,9,10]. Currently, capacitive encoders have been gaining interest owing to their simplified design, potential for further miniaturization, insensitivity to magnetic field variation, long lifespan, low cost, and high measurement accuracy [5,10,11,12].…”

“…While rotating, capacitances formed between plates change and the angle of shaft can be obtained. Many types of capacitive encoders have been proposed, and the most prominent is by modulating the angular information to two orthogonal triangular signals [6,7,8]. Encoders of this type have the advantage of high robustness to common mode errors.…”