ONERA accelerometers for future gravity mission

2020 ◽  
Author(s):  
Marine Dalin ◽  
Vincent Lebat ◽  
Damien Boulanger ◽  
Francoise Liorzou ◽  
Bruno Christophe ◽  
...  
Keyword(s):  
Attitude Control ◽  
High Performance ◽  
Small Volume ◽  
Proof Mass ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Dynamic Analyses ◽  
Electrostatic Accelerometer ◽  
Scientific Return ◽  
Gravity Mission

<p>ONERA (the French Aerospace Lab) is developing, manufacturing and testing ultra-sensitive electrostatic accelerometer for space application. ONERA has procured the accelerometer for all the previous gravity missions (GRACE, GOCE, GRACE-FO) and works to improve the scientific return of the instruments.</p><p>One way is to propose an accelerometer with 3 sensitive linear acceleration measurements as well as 3 angular acceleration measurements for the attitude control or reconstruction. Two different configurations are proposed: CubSTAR, a miniaturized version with low accuracy but adapted for constellation or nanosat; and MicroSTAR, a high accuracy accelerometer.</p><p>CubSTAR accelerometer is a small volume instrument with the same performance on the 3 axes, the baseline being 20x20x20mm proof-mass in a 15x15x20cm volume envelope. A prototype was manufactured and tested during a drop-tower test. Moreover this prototype will be tested in vibration environment to check its good mechanical behavior.</p><p>MicroSTAR accelerometer is designed with a disruptive mechanical concept allowing using a 30x30x30mm proof-mass, with the same high-performance on the 3 axes. Modal and dynamic analyses have been performed and a prototype is under manufacturing.  </p>

Sine-Wave Exciting Circuit for Quartz Vibrating Gyroscope

2013 ◽  
Vol 562-565 ◽  
pp. 417-420
Author(s):  
Qing Yi Wang ◽  
Xiao Wei Liu ◽  
Rui Zhang ◽  
Liang Yin ◽  
Zhi Ping Zhou
Keyword(s):  
High Performance ◽  
Small Volume ◽  
Angular Rate ◽  
Sine Wave ◽  
Processing Technology ◽  
Angular Rate Sensor ◽  
Square Wave ◽  
Rate Sensor ◽  
Is Design ◽  
Cmos Processing

Quartz vibrating gyroscope is a kind of angular rate sensor which is the compromise between the high performance and the small volume. Improvement of the performance is a focus of reach. In this paper, a sine-wave exciting method is discussed. A sine-wave exciting circuit is design and processed with 0.5μm CMOS processing technology. During comparing the sine-wave exciting response and the square-wave one, the sine-wave exciting circuit is more beneficial to improve the performance of the quartz vibrating gyroscope.

Laboratory and field evaluation of a small form factor head impact sensor in un-helmeted play

2017 ◽  
Vol 232 (3) ◽  
pp. 242-254 ◽  
Author(s):  
Derek Nevins ◽  
Kasee Hildenbrand ◽  
Jeff Kensrud ◽  
Anita Vasavada ◽  
Lloyd Smith
Keyword(s):  
Form Factor ◽  
Center Of Mass ◽  
False Negative ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Field Evaluation ◽  
Head Impact ◽  
Sensor Data ◽  
Small Form ◽  
Small Form Factor

Head impact sensors are increasingly used to quantify the frequency and magnitude of head impacts in sports. A dearth of information exists regarding head impact in un-helmeted sport, despite the substantial number of concussions experienced in these sports. This study evaluated the performance of one small form factor head impact sensor in both laboratory and field environments. In laboratory tests, sensor performance was assessed using a Hybrid III headform and neck. The headform assembly was mounted on a low-friction sled and impacted with three sports balls over a range of velocities (10–31 m/s) at two locations and from three directions. Measures of linear and angular acceleration obtained from the small form factor wireless sensor were compared to measures of linear and angular acceleration obtained by wired sensors mounted at the headform center of mass. Accuracy of the sensor varied inversely with impact magnitude, with relative differences across test conditions ranging from 0.1% to 266.0% for peak linear acceleration and 4.7% to 94.6% for peak angular acceleration when compared to a wired reference system. In the field evaluation, eight male high school soccer players were instrumented with the head impact sensor in seven games. Video of the games was synchronized with sensor data and reviewed to determine the number of false positive and false negative head acceleration event classifications. Of the 98 events classified as valid by the sensor, 20.5% (20 impacts) did not result from contact with the ball, another player, the ground or player motion and were therefore considered false positives. Video review of events classified as invalid or spurious by the sensor found 77.8% (14 of 18 impacts) to be due to contact with the ball, another player or player motion and were considered false negatives.

Research on Attitude Control of Spacecraft Based on ADRC

2011 ◽  
Vol 383-390 ◽  
pp. 358-365 ◽  
Author(s):  
Fu Lin Teng ◽  
Hong Yu Ge ◽  
Hong Sheng Li ◽  
Jian Hua Zhang
Keyword(s):  
Attitude Control ◽  
Disturbance Rejection ◽  
High Performance ◽  
Control Technology ◽  
Attitude Control System ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Simulation And Experiment ◽  
Attitude Controller ◽  
Very High

Modern spacecraft demands from an attitude control system very high performance and accuracy, and many new features, such as disturbance rejection capability. The recently developed active disturbance rejection control technology is applied to the attitude control of spacecraft subject to disturbances and parametric uncertainties. Simulation and experiment show significant advantages of the proposed attitude controller over the controller resulting from conventional PID approach.

Design of a Hybrid Acoustic Device Based on Proof-Mass Actuators

2012 ◽  
Author(s):  
Francesco Braghin ◽  
Francesco Castelli-Dezza ◽  
Simone Cinquemani ◽  
Ferruccio Resta
Keyword(s):  
High Performance ◽  
Proof Mass ◽  
Supporting Surface ◽  
Low Frequencies ◽  
High Frequencies ◽  
Sound Reproduction ◽  
Different Types ◽  
Magnetostrictive Actuator ◽  
Acoustic Device

The paper deals with the design of a device for sound reproduction to be fixed to a supporting surface. The device is made up of two different types of acoustic actuators based on different technologies that allow good sound reproduction in the range of frequencies from 20Hz to 20kHz. The generation of sound at high frequencies is demanded to a magnetostrictive actuator, while a more traditional magnetodynamics actuator is used to generate sound at low frequencies. The coupling between these two actuators leads to a device having small overall dimensions and high performance.

Functions of separate sensory receptors of nonauditory labyrinth of the cat

1962 ◽  
Vol 202 (6) ◽  
pp. 1211-1220 ◽  
Author(s):  
Kenneth E. Money ◽  
John W. Scott
Keyword(s):  
Intact Animal ◽  
Angular Acceleration ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
The Other ◽  
Sensory Receptors ◽  
Vestibular Tests ◽  
Normal Orientation ◽  
Angular Displacements ◽  
Vertical Semicircular Canals

A technique for plugging individual semicircular canals of cats was developed, and it was established that the plugging of a semicircular canal completely blocked its receptivity without influencing the functions of the other vestibular receptors. It was found that cats with all six semicircular canals plugged were lacking all sensitivity to angular acceleration, but they retained normal responses to linear acceleration. Results of several vestibular tests led to the conclusion that the vertical semicircular canals initiate corrections for fast angular displacements from the normal orientation when the displacements are about horizontal axes and that the otoliths initiate corrections for slow angular displacements about horizontal axes. In tests of single horizontal canals, the durations of postrotatory nystagmus were the same after rotations in opposite directions. It was concluded that in the intact animal both horizontal semicircular canals contribute equally to reception of angular acceleration in both directions.

Proportional Derivative Controller Using Discrete Kalman Filter Estimation Method for Spacecraft Attitude Control

2015 ◽  
Vol 789-790 ◽  
pp. 923-926 ◽  
Author(s):  
Mohamad Fakhari Mehrjardi ◽  
Hilmi Sanusi ◽  
Mohd Alauddin Mohd Ali ◽  
Montadar Abas Taher
Keyword(s):  
Kalman Filter ◽  
Attitude Control ◽  
Estimation Method ◽  
Angular Acceleration ◽  
Gravity Gradient ◽  
Noise Covariance ◽  
Proportional Derivative Controller ◽  
Typical Satellite ◽  
Noisy Measurements ◽  
Data Updating

This paper deals with the objective of controlling a satellite by driving a six-state discrete Kalman Filter to estimate angular rates of satellite base on control sensor noisy data. A typical satellite is assumed in a special orbit and orbital angular velocity and orbital angular acceleration are established. For completion of simulation linear dynamics model of satellites and environment disturbances model such as solar pressure and gravity gradient torque is derived as well. The simulation is progressed at discrete ten second which assumed as data updating rate from sensor. The noisy measurements are produced by sensor and these data is sent to the discrete Kalman Filter part to estimate the attitude and attitude rate. A right balance for Plant noise covariance matrix is determined and also results show that the rate estimates are appropriate for space missions.

scholarly journals Brain injury in sports

2016 ◽  
Vol 124 (3) ◽  
pp. 667-674 ◽  
Author(s):  
John Lloyd ◽  
Frank Conidi
Keyword(s):  
Brain Injuries ◽  
Scientific Evidence ◽  
Head Injuries ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Impact Testing ◽  
Common Belief ◽  
Percentage Reduction ◽  
Football Helmets

OBJECT Helmets are used for sports, military, and transportation to protect against impact forces and associated injuries. The common belief among end users is that the helmet protects the whole head, including the brain. However, current consensus among biomechanists and sports neurologists indicates that helmets do not provide significant protection against concussion and brain injuries. In this paper the authors present existing scientific evidence on the mechanisms underlying traumatic head and brain injuries, along with a biomechanical evaluation of 21 current and retired football helmets. METHODS The National Operating Committee on Standards for Athletic Equipment (NOCSAE) standard test apparatus was modified and validated for impact testing of protective headwear to include the measurement of both linear and angular kinematics. From a drop height of 2.0 m onto a flat steel anvil, each football helmet was impacted 5 times in the occipital area. RESULTS Skull fracture risk was determined for each of the current varsity football helmets by calculating the percentage reduction in linear acceleration relative to a 140-g skull fracture threshold. Risk of subdural hematoma was determined by calculating the percentage reduction in angular acceleration relative to the bridging vein failure threshold, computed as a function of impact duration. Ranking the helmets according to their performance under these criteria, the authors determined that the Schutt Vengeance performed the best overall. CONCLUSIONS The study findings demonstrated that not all football helmets provide equal or adequate protection against either focal head injuries or traumatic brain injuries. In fact, some of the most popular helmets on the field ranked among the worst. While protection is improving, none of the current or retired varsity football helmets can provide absolute protection against brain injuries, including concussions and subdural hematomas. To maximize protection against head and brain injuries for football players of all ages, the authors propose thresholds for all sports helmets based on a peak linear acceleration no greater than 90 g and a peak angular acceleration not exceeding 1700 rad/sec2.

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