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This article proposes an absolute-type inductive angle sensor for detecting the position of the YRT turntable bearing. The sensor comprises a multispeed incremental measuring unit and a single-speed absolute measuring unit sharing the same stator, rotor, and excitation circuit. The stator is composed of a ferromagnetic gear groove, two groups of excitation coils, and one group of induction coils arranged according to certain rules. The end cover of the YRT turntable bearing is machined as rotor and it rotated eccentrically relative to the rotation of the stator. A bridge circuit is used to acquire and process the sensor signal from the single-speed measuring unit. Compared with the traditional dual-channel absolute measurement, the proposed measurement method avoids the effects of different magnetic circuit disturbances on signal quality and measurement accuracy, and has more advantages in the volume and weight of the sensor. The structure and working principles of the sensor are presented in detail, the feasibility of sensing scheme is verified via simulation, and a sensor prototype is designed for the final experiment. Experimental results show that the accuracy of the sensor prototype is –0.06758° to 0.1203° before compensation and –0.001139° to 0.0015° after compensation in the range of [0°, 360°], respectively.

Absolute Inductive Angular Displacement Sensor for Position Detection of YRT Turntable Bearing

Abstract The commercially available and research-developed positive-type ankle joints do not provide eversion and inversion movements and are limited to dorsiflexion and plantar-flexion. The aim of the research is to create an ankle joint that is simple to install, low in cost and closes in performance to the biological joint. The passive ankle joint is designed to perform dorsiflexion, plantar-flexion, eversion, and inversion movements. A biomechanical test was performed to find the similarity between the functions of the engineered ankle joint and the biological ankle joint. The conclusions show, the designed ankle joint on the simplicity of its structure and components, has come close to the biological function of the ankle in terms of angles. 

Kinematic analysis for passive multi-axes ankle joint

In order to meet the requirements of high precision and rigidity of the two-dimensional turntable, it is necessary to carry out the structural design and position accuracy analysis of the two-dimensional turntable. The study found that the structure of the turntable, the resistance torque, the shaft structure, and the selection and design of the motor and sensor are all key factors affecting the performance of the two-dimensional turntable. In this paper, a method for structural design and simulation of a two-dimensional space turntable is proposed. In the process of structural design, these key factors are analyzed in detail, and the statics, modal and dynamic simulation analysis of the two-dimensional turntable are carried out using ANSYS Workbench software. Through simulation analysis, various indicators of the turntable are checked. Finally, it is concluded that the simulation results fully meet the requirements of the design indicators, which verifies the rationality of the design method and provides a strong basis for the structural design of the two-dimensional space turntable.

Structural Design and Simulation Analysis of Two-Dimensional Space Turntable

Slewing support is widely used in large slewing machinery such as rocket launching platform, wind turbine and port crane. The accurate analysis of the internal stress in the raceway of ball roller is an important basis for studying the cause of bearing fatigue failure and improving the reliability of slewing support. In this paper, the finite element model of thrust angular contact rotary support was established in ANSYS. The stress distribution of the raceway of the ball under different working conditions was calculated by using bilinear isotropic plastic materials and linear elastic materials, and the equivalent stress resulted of the contact surface were compared with the Hertz contact model. This paper studied the factors that affect the distribution of the equivalent stress on the contact surface, calculates the ratio of the equivalent shear stress and the normal stress on the contact surface by finite element method, namely the equivalent friction coefficient, and studied the effect of the equivalent friction coefficient on the distribution of the stress inside the rolling ball. Simulation results show that plasticity occurs in the rolling ball.

Sub-surface stress analysis of slewing bearing ball based on plastic deformation

Turntable bearing is widely used in heavy industry. Raceway structure is the most direct factor that affects the contact stress change between raceway and rolling element. Therefore, it is the key to improve the safety of turntable bearing and determine the processing technology reasonably to study the stress distribution of contact area in different raceways. In this paper, the finite element slicing model of rolling element and raceway in turntable bearing is established in ABAQUS. Under the action of axial load and radial load, the distribution characteristics of contact stress of raceway are compared under different raceway structures. The finite element results show that, compared with the two-point contact disc bearing, the rolling element and raceway in four point contact turntable bearing are in four point contact under axial load, The contact stress distribution of raceway is uniform, which is a pair bearing distribution. However, when only considering the radial load, the rolling element and raceway are in two-point contact, and the contact stress distribution characteristics are consistent with those of two-point contact rotary table bearing.

Analysis of the influence of raceway structure on contact characteristics of turntable bearing

The stability of the rolling elements in the slewing bearing is an important factor that determines the smooth rotation of the slewing bearing. The slewing radius of the slewing bearing is large and the load is complicated. In this paper, the contact relationship between the rolling elements and the raceway is established by establishing a slice model of the slewing bearing. Considering the effects of axial load and radial load, respectively, the contact deformation and displacement changes of the rolling elements are analyzed. The simulation results show that the rolling elements of the two-point contact slewing bearing rotate during the load process, and the four-point contact slewing bearing is in the axial direction. Under load, the rolling contact state in the raceway with the raceway is stable without spinning; under radial load, the contact relationship between the rolling element and the four-point contact raceway at this time is essentially two-point contact, but compared to the one used Two-point contact raceway, the rolling elements have better radial stability in the newly designed raceway

Jianwei Chen

Papers

Sub-surface stress analysis of slewing bearing ball based on plastic deformation

Analysis of the influence of raceway structure on contact characteristics of turntable bearing

Analysis of the influence of the contact mode of the rolling elements of the slewing bearing on its stability