Identification of Euler angles of permanent magnet spherical motor rotor based on Hall sensors array

Abstract

Rotor position detection is an indispensable link in the closed-loop control system of permanent magnet spherical motors. This paper proposes a method to determine the position of the rotor by calculating the Euler angles using the Hall sensors array. The accuracy of Euler angle calculation is related to the installation position and quantity of the sensors. This article uses a spherical quadrilateral triangle model to determine the location of the Hall sensors. According to the different rotation axis around which the rotor rotates, the projection planes are calculated respectively. The output result of the Hall sensor array is converted into an encoded signal. The rotor magnetic pole coordinates are calculated according to the encoded signal. The coordinates are projected onto the corresponding projection plane, and the angle of rotation of the rotor is calculated. When the angles obtained at multiple consecutive sampling moments are the same, the angle corresponding to the intermediate moment is used as a sign quantity, and the angle corresponding to each sampling time is calculated according to the sign quantity. Finally, in order to verify the correctness of the method proposed in this paper, the experiments are carried out to verify the different motion postures of the spherical motor, and the experimental results verify the feasibility of the proposed method for calculating Euler angles of the permanent magnet spherical motor.