ROTARY ANGLE SENSOR FOR MONITORING THE POSITION OF ACTUATORS

The reliability of actuators is determined by the criteria of limit states, which are assessed by different types of sensors. The reliability of sensors depends on their design properties, features of technological support of their quality in the manufacturing process. The angular position of the rotary links of actuators is determined by different types of sensors, including rotary angle sensors. A non-contact sensor is considered. The sensor operation is based on the Hall measurement principle, which ensures its structural simplicity, reliability and long service life. The accuracy characteristics of the sensor are determined by manufacturing errors of its individual parts. The purpose of the study is to develop a model of sensor error depending on manufacturing inaccuracies of the permanent magnet, which is part of its primary measuring transducer. Materials and Methods. The rotary angle sensor manufactured by Specialized Design Bureau “Induction” has been chosen as a prototype, during the production of which deviations in its technical cha¬racteristics caused by defects in the permanent magnets have been detected. The methods used in the paper include theoretical mechanics, calculation of electric and magnetic circuits, and numerical modelling. The calculations have been performed for a cylindrical permanent magnet with radial magnetization, wherein the magnetization vector is shifted in the radial direction. To perform the error calculations, the schemes of the arrangement of defective magnets relative to the magnetization vector of the external field created by additional magnets have been used. The coaxial arrangement of additional magnets is ensured by arranging them in coaxial cylindrical guides. Results. Analytical dependencies that relate the displacement of the magnet dipole relative to its geometric centre with the error in determining the rotary angle have been presented. The sensor errors have been shown in sketches of the primary measuring transducer in various positions of the magnet relative to the Hall elements in the primary transducer. Conclusion. The research results can be used in engineering facilities that allows for a quantitative assessment of the radial displacement of the magnetic dipole relative to the geometric centre of the magnet. The practical significance of the results lies in the rejection of permanent magnets at the stage of incoming inspection of the permissible displacement of the magnetic dipole relative to its geometric centre.