LADRC-Based Magnetic Field Measurement Method for a Nuclear Magnetic Resonance Rotation Sensor

Magnetic field measurement is fundamental to nuclear magnetic resonance rotation sensors (NMRRS). A phase-locked loop (PLL)-based measurement with two nuclear isotopes is commonly applied to observe the magnetic field. However, the phase-loop and frequency-loop of the nuclear isotopes cannot be optimized simultaneously by a PLL-based method. In this paper, an approach based on a linear active disturbance rejection controller (LADRC) is proposed for synchronous phase-loop control of the two nuclear isotopes. Meanwhile, the frequencies of the nuclear isotopes are observed by linear extended state observers (LESOs). The phase and frequency loops can be decoupled and optimized with the proposed method. An experimental NMRRS prototype used for verification is built. The effectiveness and the feasibility of the proposed method are validated with the experimental results.

Rotational Seismology with a Quartz Rotation Sensor

We describe the construction and performance of a new high-precision ground- or platform-rotation sensor called the Quartz Rotation Sensor (QRS). The QRS is a mechanical angular accelerometer that senses rotational torque with an inherently digital, load-sensitive resonant quartz crystal. The noise floor is measured to be ∼45 pico-radians/root (Hz) near 1 Hz, and the resonant period of the sensor is about 10 s, making it a broadband sensor. Among similarly sized broadband rotation sensors, this represents more than two orders of magnitude improvement in noise floor near 0.1 Hz. We present measurements of rotational components of teleseismic waves recorded with the sensor at a vault. The QRS is useful for rotational seismology and for improving low-frequency seismic isolation in demanding applications such as the Laser Interferometer Gravitational-Wave Observatories.

Arm Cycle Ergometer Electro-Mechanical System Design For Post-Stroke Medical Rehabilitation

This study was done to make the electro-mechanical arm ergometer cycle system used as post-stroke patient physiotherapy. The management system was expected to set the rotary frequency according to the therapeutic needs. To set the frequency of the rotation, the PID control with rotation sensor was used as feedback. The rotating sensor used consisted of the optocoupler and a rotary encoder. Based on the research that has been done, obtained constants of Kp = 0055, Ki and Kd = 2545 = 0.00005. Constants were selected because they were the most optimum constant trial and error method. The system is made to have a more significant percentage of error of 5%. In this study, the response time values obtained for each additional mass of the load at each frequency setting result are increased.

Design of CDI (Capasitive Discharge Ignition) and Motor Spark Plugs Test Kits

The Ignition on a motorcycle is an electrical system that produces sparks in the combustion chamber. If there is a mass of ferromagnetic material moving closer to the sensor, then the pulser will generate an electric current. Greater the electric current it generates. With the working principle of such a pulser, it can be used as a rotation sensor and sent to the ignition coil to produce a higher voltage which will produce sparks at the end of the spark plug electrode. The perfection of the system affects the motor work system. A good CDI condition will make it easier to increase the RPM (Rotations Per Minute) and when the spark plugs are in good condition, the motorbike's performance is getting optimal. There can be a useful tool for analyzing the damage to the CDI and the spark on the spark plug by integrating the electronic system in the motor ignition system. An electronic circuit that connects the motorcycle's ignition system through the output of the pulser circuit signal, which triggers the CDI input instead of the pulse magnet. Because the CDI and motor spark plugs are one of the main components that play an important role in the performance of the combustion motor. So that the electrical system can work without using mechanics and can be used as a tool to be able to analyze CDI damage and motor spark plug performance because CDI and spark plugs are some of the main components that play an important role in combustion motor performance. The result is that the tool can test CDI and motor spark plugs efficiently after which it can conclude the damage and can distinguish the characteristics of the CDI and the motor plugs.

Comparing Direct Observation of Torsion with Array-Derived Rotation in Civil Engineering Structures

In this article, we analyze the rotation rates in a building derived from a network of translation sensors and recorded by a rotation sensor. The building is Grenoble city hall, a reinforced concrete structure with permanent accelerometric translation sensors at the top and bottom of the building. A temporary experiment was conducted, consisting in installing a BlueSeis-3A rotation sensor for more than 24 h at the top of the structure. The ambient vibrations were analyzed. The amplitudes of translation accelerations and rotation rates at the top and bottom of the building, along with their variations over time, were analyzed. The acceleration/rotation ratios were then compared with the impulse wave velocities derived from seismic interferometry by deconvolution between the top and bottom. Perspectives with regard to building imaging, time monitoring of structural integrity and understanding the contribution of rotations to the structure’s response are discussed, offering new suggestions for research projects.