Study on the electromagnetic fields of a novel small-angle transducer used in high-precision inertial sensors

Purpose Microsyn signal generators have been used in high-precision inertial sensors for their good structural stiffness and high sensitivity. However, as the stator and the rotor of the microsyn are both constructed of silicon-steel laminations with high permeability, an extremely small non-concentricity between the stator and rotor of microsyn will cause two random reaction torques acting on the output axis. As a result, difficulty arises in compensating for these random reaction torques. This study aims to investigate the electromagnetic fields of a novel angular transducer characterized by high sensitivity. Design/methodology/approach Based on the operation principles of the new transducer, the output voltage is decided by the time rate of change of the net magnetic flux of each output pole. The transient analysis of the electromagnetic field of the transducer is carried out by ANSYS Maxwell-3D. Findings The distributions of the magnetic flux of the transducer’s interior and eddy current on the rotor are consistent with the results of theory analysis. Moreover, the leakage flux mainly distributes nearby the excitation poles. The novel small-angle transducer also possesses a remarkably low reaction torque and power loss. Practical implications Study on the electromagnetic fields of the new transducer not only provides a powerful basis to further improve the precision of the new transducer but also expands the scope of applications of the new transducer. Originality/value This new transducer is not only characterized by a high sensitivity, high linearity and fast response but also extremely low reaction torque and power losses. Thus, the new transducer is suitable for high-precision inertial sensors.

Analysis of the Output Characteristics of a Novel Small-Angle Transducer Used in High-Precision Inertial Sensors

This paper presents the design of a novel small-angle transducer characterized by a simple structure, fast response and very low reaction torque. A theoretical model is presented which describes the linear relationship between the output voltage and the angular displacement when the rotor rotates away from the null position. By analysis of the theoretical model, it is revealed that the small-angle transducer possesses a very high linearity within ±4° and a high sensitivity (approximately 0.34 V/°), and the parameters affecting output characteristics can be obtained. Furthermore, it is found that the transducer sensitivity can be improved by optimizing the load impedance and excitation frequency. These findings are verified by numerical evaluations. In addition, the established theoretical model and simulation analysis provide a quantitative method for analyzing the output characteristics of the novel small-angle transducer.

Experimental study on initial loss of tension in bolted joints

The initial loss of tension in individual bolts after initial tightening obviously affects the level and the stability of the clamp load in bolted joints. A high-precision instrument to analyze the clamp load loss was developed. In this instrument, an Atlas Copco’s high performance spindle with an accuracy of ±2.5% under the conditions of one million duty cycles was used to tighten the test bolts and nuts. A rotary torque-angle transducer was integrated in the tightening spindle to measure the tightening torque. KMR force washer with a repeatability of < ±1% was applied to monitor the clamping force in real time. Using this instrument, the design of experiment analysis was performed to determine the effect of variables on the initial loss of tension. Those variables included the joint materials, the fastener class, the gasket grade, the lubrication, the surface roughness, the tightening speed, and the number of repeated tightening. The results showed that the tightening speed and the number of repeated tightening had a significant effect on the initial loss of tension. Moreover, a process criterion of eliminating plastic deformation was proposed to minimize the initial loss of tension. The findings presented in this paper will be expected to enhance the reliability and the safety of bolted assemblies, especially in critical applications.

Research on Solving the Watertightness Problem of Underwater Angular Sensor Driven by New Magnetism

The angular sensor is frequently used to measure relative angle changes between two structural components, from the perspective of working principles, it can be divided into "angular displacement" and "linear displacement" angular sensor. In the application under water, the watertightness of traditional angular sensor can not meet the requirements, and the sensor is easy to corrode in the sea water, causing damage to the sensor. The outer shell of new underwater angular sensor is made of 304 stainless steel, by making use of the exclusion principle of magnet and the synchronous changes of magnetic axis driven by magnetism, the angle transducer in the body can measure the relative angle changes between two structural components under water.

Design of a LEGO NXT Two-Wheeled Self-Balanced Robot Based on Inverted Pendulum Model

Two-wheeled self-balanced robot based on the inverted pendulum model belongs to the category of the wheeled robots and it shares many characters with inverted pendulum, which are non-linear, strong coupling, multi-variable and parameter uncertainty. Because there are many methods to keep this unstable robot self-balanced, this kind of robot has become an ideal platform to verify various kinds of control theories. In this paper, the two-wheeled robot is built on LEGO NXT set and depends on the sensors like gyro, angle transducer to keep upright. The mathematic and kinetic model of the robot is established according to the Lagrangian Dynamics and state-space equation of the whole system is presented. At last, a kind of state feedback control with the state observer is set up to make the system closed and stable.

Measurement Research of Pipe Automatic Welding Bug Speed

Walking speed of pipe automatic welding bug influences directly the quality of pipe welding. Measurement of walking speed of pipe automatic welding bug is very necessary. Direct measurement of walking speed of pipe automatic welding bug has the certain difficulty. Indirect measurement of walking speed of pipe automatic welding bug is realized by angle transducer installed in pipe automatic welding bug. Measuring precision of walking speed of pipe automatic welding bug is influenced by angle signal sampling frequency , angle resolution of angle transducer, walking speed of pipe automatic welding bug, the resolution of the AD converter and so on. The method of subsection of speed is adapted to measure indirectly walking speed of pipe automatic welding bug . Its effect is well.