PR_25_ChannelizedMonitor (0925133-PO)

Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 0925133. A spectrum analyzer device is designed using silicon microring CROWs which measures the C-band optical spectrum with no moving parts.

MEASUREMENT OF WIND POWER AND ENERGY USING AN ANEMOMETER WITHOUT MOVING PARTS

The paper deals with the application of a newly developed anemometer without moving parts. It is digitized and has built-in electronics that convert the vibrations of two aluminum fixed frames into two digital signals: one, which shows the strength (speed absolute value)) of the wind, and the other, which shows its direction. Both of these signals are used to calculate wind power and energy. Earlier works have shown that the two-bit stochastic digital measurement method overcomes (eliminates) the problem of the offset of the analog adder. The authors of this paper apply this idea to the digital output of the sensor, where the role of the offset of the analog adder is taken over by the integral nonlinearity of the digital output of the anemometer. The first step in this direction is digitally dithering the sensor output. This principle is presented in detail, as well as a rough estimate of the accuracy gain in measuring wind energy. The obtained result shows that the accuracy in measuring wind energy is not worse than the limit accuracy in the case of a cup anemometer that generates sinusoidal voltage.

Development of Wrist Interface Based on Fully Actuated Coaxial Spherical Parallel Mechanism for Force Interaction

To develop a wrist robotic exoskeleton-type interface (REI) for force interaction, it should have a suitable range of motion similar to human wrist activities of daily living, large torque output performance, and low moving parts inertia for dynamic motion response to cover the human behavior frequency. In this paper, a wrist REI based on a fully actuated coaxial spherical parallel mechanism (CSPM) is proposed to satisfy the aforementioned features. The fully actuated CSPM-based wrist REI (FC-WREI) has the characteristics of pure rotation similar to the human wrist, high torque output by parallel torque synthesis, and low moving parts inertia due to the base arrangement of the actuators. Due to the mechanical advantages and design optimization, the FC-WREI maximally provides torque as much as 56.49–130.43% of the maximum isometric torque of the human wrist, while providing a consistent range of motion to the human wrist without interference problem. Moreover, it is confirmed that the inertia of the FC-WREI is up to 5.35 times lower than similar devices. These advantages of the FC-WREI mean that the device is applicable to various fields of REIs for force interaction.

Level gauges. Application features

This paper considers various aspects of application of the most common types of level gauges – magnetostrictive, servo-driven, radar and reflex. Much attention is paid to accuracy of level gauges, expressed in error and uncertainty, including those referred to the legally regulated measuring instruments. Due to the fact that the most of the level gauges are installed on tanks, the requirements for them, given in the standards, and possible ways to improve the accuracy of level gauges installed on tanks have been analyzed. Methods of verification and calibration of level gauges are considered, including both verification on standard units using water, and carried out by the simulation method. The requirements for the metrological control of level gauges with moving parts are stated. It is shown that for verification of such level gauges, it is necessary to carry out measurements when the water moves both up and down. However, there is no need to take measurements, as in determining the variation, at the same points when the water moves up and when the water moves down. Some known caution is needed when using the results of the verification of level gauges by the simulation method. Especially big differences in the results of verification on the standard unit with water and the simulation method are observed for magnetostrictive level gauges. This difference is due to the fact that in these level gauges, the float slides along the pipe with a certain friction, and in the simulation method, the float moves by hand and its movement does not depend on friction.

Electromagnetic Devices with Moving Parts—Simulation with FEM/BEM Coupling

The numerical analysis of electromagnetic devices by means of finite element methods (FEM) is often hindered by the need to incorporate the surrounding domain. The discretisation of the air may become complex and has to be truncated by artificial boundaries incurring a modelling error. Even more problematic are moving parts that require tedious re-meshing and mapping techniques. In this work, we tackle these problems by using the boundary element method (BEM) in conjunction with FEM. Whereas the solid parts of the electrical device are discretised by FEM, which can easily account for material non-linearities, the surrounding domain is represented by BEM, which requires only a surface discretisation. This approach completely avoids an air mesh and its re-meshing during the simulation with moving or deforming parts. Our approach is robust, shows optimal complexity, and provides an accurate calculation of electromagnetic forces that are required to study the mechanical behaviour of the device.