scholarly journals Method of reference image selection to provide high-speed aircraft navigation under conditions of rapid change of flight trajectory

2021 ◽  
Vol 8 (85) ◽  
Keyword(s):  
High Speed ◽  
Rapid Change ◽  
Reference Image ◽  
Flight Trajectory ◽  
Aircraft Navigation

Current Command Compensation Method for the PM Servo Motor Considering Voltage Saturation Caused by Both Rapid Change in the Current Command and High-Speed Rotation

2014 ◽  
Vol 134 (7) ◽  
pp. 691-698
Author(s):  
Yoichi Egashira ◽  
Masaya Harakawa ◽  
Takayuki Ozaki ◽  
Hiroto Takei ◽  
Atsuo Haishi ◽  
...  
Keyword(s):  
High Speed ◽  
Rapid Change ◽  
Compensation Method ◽  
Servo Motor ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Voltage Saturation

scholarly journals Characteristics of verbal fluency in patients with a primary episode of bipolar affective disorder

2020 ◽  
Keyword(s):  
Depressive Symptoms ◽  
Affective Disorder ◽  
Test Performance ◽  
Verbal Fluency ◽  
High Speed ◽  
Bipolar Affective Disorder ◽  
Rapid Change ◽  
Verbal Fluency Test ◽  
Manic Symptoms ◽  
Fluency Test

A study was conducted using the verbal fluency test of 153 patients with a primary episode of bipolar affective disorder: with prevalence of depressive symptoms (44 men and 75 women), with prevalence of manic symptoms (15 men and 8 women), and with simultaneous presence of depressive symptoms and manic symptoms phase change (6 men and 5 women). Significant impairment of test performance in patients with depression with respect to phonetic and semantic verbal fluency was revealed: the average number of words per letter "K" per 60 sec. in all patients 14,1±2,7 words, in men – 13,8±3,1 words, in women - 14,3±2,4 words, on the letter "P" – 12,5±2,8 respectively words, 12.3±3.2 words, 12.6±2.6 words, "Male Names" – 13.1±2.6 words respectively, 12.8±3.0 words, 13.3±2,4 words; "Fruits / furniture" – 12.0±2.4 words, 11.9±2.8 words, 12.1±2.1 words. Deterioration in the performance of semantic and phonemic verbal fluency test reflects the state of bradypsychism inherent in patients with depressive variant, which manifests a slow thinking rate, difficulty concentrating attention, motor inhibition, deterioration of operational capacity, rapid exhaustion. In patients with a maniacal variant, the high speed of the test is offset by a large number of errors due to the chaotic mental activity, instability and scattering of attention, the difficulty of maintaining focus of attention: the indicators were respectively 21.7±5.7 words, 22.5±5.7 words, 20,3±6.0 words; 20.3±5.6 words, 21.1±5.5 words, 19.0±5.9 words; 20.5±5.4 words, 21.2±5.2 words, 19.1±5.7 words; 19.5±5.4 words, 20.2±5.2 words, 18.1±5.7 words. In patients with mixed variants, the indicators of verbal fluency are reduced due to the influence of complex polymorphic symptoms with rapid change of state: respectively 16.5±5.6 words, 18.2±6.1 words, 14.4±4.8 words; 14.5±5.4 words, 16.2±5.7 words, 12.4±4.8 words; 15.4±5.4 words, 17.0±5.8 words, 13.4±4.8 words; 13.9±5.0 words, 15.5±5.3 words, 12.0±4.3 words. The differences in scores across all subtests in all groups between men and women are statistically insignificant (p>0.05).

Novel Type of Biaxial Wheel-Type Haptic Input Device With MR-Brakes to Control Hydraulic Multi-Axis Manipulators

2017 ◽  
Author(s):  
Adam Myszkowski ◽  
Tomasz Bartkowiak ◽  
Roman Staniek
Keyword(s):  
High Speed ◽  
Angular Displacement ◽  
Rapid Change ◽  
Initial Study ◽  
Resistance Force ◽  
Input Device ◽  
Motion Direction ◽  
University Of Technology ◽  
Motion Resistance ◽  
Haptic Input

In the paper, authors present a design of a novel input device, in which, thanks to two ergonomically placed wheels, the operator can control the multi-axis manipulator with a single hand. The application of rotating elements provides the following benefits: achieving unlimited angular displacement, controlling numerous number of axes thanks to the certain combination of wheels motions, assigning force and position amplification individually, what helps to obtain both high speed and precision. In order to generate feedback force in the joystick, dedicated MR brakes were designed and built. The proposed feedback approach is an example of admittance control [1]. The joystick was built and tested at the Institute of Mechanical Technology of Poznan University of Technology. In the article, a theoretical model of the brake was shown together with analysis and discussion of its parameters. Additionally, it was supplemented with the results of theoretical and simulative studies. The paper also contains the outcome of the initial study focused on the analysis of the functionality, ergonomics and possibility of two-, three- and four axis control. It showed that the control algorithms played an essential role in motion control. They allow a rapid change of the generated resistance force during the change of motion direction. The obtained results validated the assumed design of the joystick with rotary elements and applied MR brakes due to the possibility of precisely control the motion resistance.

scholarly journals Serve Ball Trajectory Characteristics of Different Volleyballs and Their Causes

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 146
Author(s):  
Takehiro Tamaru ◽  
Shinichiro Ito ◽  
Masaki Hiratsuka
Keyword(s):  
High Speed ◽  
Trajectory Analysis ◽  
Force Measurement ◽  
Aerodynamic Characteristics ◽  
Flight Trajectory ◽  
Fluid Force ◽  
Spin Speed ◽  
Trajectory Measurement ◽  
Ball Trajectory ◽  
Effective Service

Volleyball is a sport that starts with a serve, so effective service is essential to win the game. The trajectory of the ball is complicatedly affected by the fluid force, which depends on the speed, spin speed, and panel shape. To understand the aerodynamic characteristics of the ball and to propose an ideal serve method, we measured the fluid force and flight trajectory. The fluid force applied to the ball was measured at a wind speed of 4–30 m/s in the wind tunnel. The fluid force on the ball was strongly dependent on the ball type and orientation of the panel. In the flight trajectory measurement, the trajectory of the ball was measured using a high-speed camera under controlled speed and spin speed using a shotting machine. The effect of the panel orientation shown by the fluid force measurement was consistent with the results of the trajectory analysis, clarifying the importance of the panel orientation in serving.

scholarly journals Investigation on the Effects of Prefabricated Crack and Strain Rate on Uniaxial Compressive Properties of Frozen Silty Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Dongdong Ma ◽  
Ezra Esanju Kaunda ◽  
Kun Huang
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Shear Failure ◽  
Rapid Change ◽  
Stress Wave Propagation ◽  
Peak Strain ◽  
Soil Specimen ◽  
Silty Soil ◽  
Fracturing Process ◽  
Deformation Properties

To investigate the uniaxial compressive strength and deformation properties of frozen silty soil with prefabricated crack under various strain rates, the static uniaxial compressive tests were conducted for frozen silty soil using three kinds of binder materials to select the suitable prefabricated crack manufacturing method. Afterward, the static and dynamic stress-strain curves of frozen silty soil with different prefabricated crack numbers were obtained based on static and splitting Hopkinson pressure bar (SHPB) tests. In addition, the high-speed camera was employed to record the fracturing process of frozen silty soil under impact loads. Results indicated that the frozen silty soil specimens with no binder showed higher static strength compared with other two binder materials (plaster and Vaseline). The strength growth rate of frozen silty soil showed three-stage (fast-slow-rapid) change characteristics. The peak strain of frozen silty soil under static loads scope was higher compared with that under dynamic loads, while its dynamic peak strain with various prefabricated crack numbers was remarkably rate-dependent. The absorbed energy density of frozen silty soil was subject to a negative (positive) relationship with the prefabricated crack numbers (strain rate). The dominated crack of intact frozen silty soil specimen finally presented Y-shaped shear failure. However, tensile cracks parallel to stress wave propagation direction were observed for the frozen silty soil specimen with prefabricated crack.

High-Speed and Robust Scene Matching Algorithm Based on ORB for SAR/INS Integrated Navigation System

2012 ◽  
Vol 241-244 ◽  
pp. 439-443
Author(s):  
Fang Chen ◽  
Yun Xi Xu
Keyword(s):  
Navigation System ◽  
High Speed ◽  
Hamming Distance ◽  
Reference Image ◽  
Integrated Navigation ◽  
Sar Images ◽  
Matching Algorithm ◽  
Integrated Navigation System ◽  
Scene Matching ◽  
Position Errors

It is important that scene matching algorithm should satisfy the requirements of real-time, robustness and high-precision for inertial integrated navigation system. And considering the serious distortion and speckle noises of SAR images, we proposed a new scene matching algorithm for the SAR/INS integrated navigation system with high-speed and robustness based on Oriented FAST and Rotated BRIEF (ORB). We started by detecting scale-space FAST-based features in combination with an efficiently computed orientation in the image. Then, we calculated feature point's Rotation-Aware BRIEF descriptor which performs well with rotation and match features by computing Hamming distance between descriptors. Finally, we adopted GroupSAC which are proposed recently to remove the false matching points and the least square algorithm for getting the distortion transformation parameters that are the aircraft position errors and rotation transform parameters between real image and reference image. Experimental results on real SAR images indicate that our algorithm is invariant to various image transformations due to rotation and scale, and also robust to speckle noise and extremely efficient to compute, better than SIFT in many situations. Therefore, our algorithm can meet the high performance needs for matching navigation in the SAR/INS integrated navigation system.

Current Command Compensation for PM Servo Motor Considering Voltage Saturation Caused by Both Rapid Change in the Current Command and High-Speed Rotation

2016 ◽  
Vol 196 (2) ◽  
pp. 24-33
Author(s):  
YOICHI EGASHIRA ◽  
MASAYA HARAKAWA ◽  
TAKAYUKI OZAKI ◽  
HIROTO TAKEI ◽  
ATSUO HAISHI ◽  
...  
Keyword(s):  
High Speed ◽  
Rapid Change ◽  
Servo Motor ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Voltage Saturation

Parameter study of Variation noise in outdoor of air conditioner

2021 ◽  
Vol 263 (4) ◽  
pp. 2822-2829
Author(s):  
Minkyu KIM ◽  
Byoungha Ahn ◽  
Simwon Chin
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
High Speed ◽  
Rapid Change ◽  
Volume Control ◽  
Parameter Study ◽  
Air Conditioner ◽  
Load Variations ◽  
Compressor Inlet ◽  
The Difference

In the outdoor unit of a room air conditioner, the main factors that made it possible to vary the ability of cooling and heating are the development of BLDC motors, advances in inverter technology, and the development of refrigerant volume control technology. The main reason for this change in cooling and heating capacity is that it is possible to change the RPS of compressors. As the range of the compressor's RPS expands, so does the range of response to load variations. This is mainly based on the capacity of the high-pressure refrigerant produced by the compressor. When the compressor rotates at high speed or low speed, the difference in noise occurs depending on the difference in rotational speed. Of course, fans and motors also contribute to noise fluctuations, but the overall governing factor is the greater contribution of refrigerant from compressors and compressors. The refrigerant flows into the cycle configured in the outdoor unit and varies in speed and flow rate depending on the amount of refrigerant. This results in vibration and noise appearing in the form of radiations, resonances, solid sounds, resonances, and so on. There are several factors that can cause vibration or noise changes depending on the flow velocity and flow rate. In this paper, we selected reactance of compressor motors, mufflers directly connected to compressor discharge ports and accumulator at compressor inlet where fluid vibrations occur the most. First of all, reactance of motor responds quickly to load fluctuations and has a large instantaneous torque to instantaneous load fluctuations. The muffler, which is directly connected to the compressor discharge port, is the first Cavity where high-pressure gas meets, and can evaluate the concentration of kinetic energy that generates noise and improve the collection center to reduce fluctuating noise. The Accumulator is the part with the lowest temperature of refrigerant gas entering the compressor, and the rapid change in the flow path causes the most fluid to generate vibration and radiation of the structure. For this reason, we select three elements first. In this paper, we specifically describe the background of selecting three elements of an air conditioning outdoor unit for the variability of noise over RPS changes. We demonstrate that these factors can review the feasibility of the experiment, explain the results of the analysis, and possibility of reduce the variation noise.

High-speed autonomous quadrotor navigation through visual and inertial paths

2018 ◽  
Vol 38 (4) ◽  
pp. 486-504 ◽  
Author(s):  
Tien Do ◽  
Luis C Carrillo-Arce ◽  
Stergios I Roumeliotis
Keyword(s):  
Optical Flow ◽  
High Speed ◽  
The Other ◽  
Reference Image ◽  
Short Baseline ◽  
Adverse Conditions ◽  
Flow Algorithm ◽  
Commercial Off The Shelf ◽  
Indoor Spaces ◽  
Gravity Direction

This paper addresses the problem of autonomous quadrotor navigation within indoor spaces. In particular, we focus on the case where a visual map of the area, represented as a graph of linked images, is constructed offline (from visual and potentially inertial data collected beforehand) and used to determine visual paths for the quadrotor to follow. In addition, during the actual navigation, the quadrotor employs both wide- and short-baseline random sample consensuses (RANSACs) to efficiently determine its desired motion toward the next reference image and handle special motions, such as rotations in place. In particular, when the quadrotor relies only on visual observations, it uses the 5pt and 2pt algorithms in the wide- and short-baseline RANSACs, respectively. On the other hand, when information about the gravity direction is available, significant gains in speed are realized by using the 3pt+1 and 1pt+1 algorithms instead. Lastly, we introduce an adaptive optical-flow algorithm that can accurately estimate the quadrotor’s horizontal velocity under adverse conditions (e.g., when flying over dark, textureless floors) by progressively using information from more parts of the images. The speed and robustness of our algorithms are evaluated experimentally using a commercial-off-the-shelf quadrotor navigating in the presence of dynamic obstacles (i.e., people walking) along lengthy corridors and through tight corners, as well as across building floors via poorly lit staircases.

Studies and simulations on the flight trajectories of spinning table tennis ball via high-speed camera vision tracking system

2018 ◽  
Vol 233 (2) ◽  
pp. 210-226 ◽  
Author(s):  
Ping Wang ◽  
Qian Zhang ◽  
Yinli Jin ◽  
Feng Ru
Keyword(s):  
High Speed ◽  
Tracking System ◽  
Tennis Ball ◽  
Table Tennis ◽  
Flight Trajectory ◽  
Tennis Players ◽  
Simulated Trajectory ◽  
Ideal Tool ◽  
Ball Flight ◽  
Actual Trajectory

When a table tennis ball is hit by a racket, the ball spins and undergoes a complex trajectory in the air. In this article, a model of a spinning ball is proposed for simulating and predicting the ball flight trajectory including the topspin, backspin, rightward spin, leftward spin, and combined spin. The actual trajectory and rotational motion of a flying ball are captured by three high-speed cameras and then reconstructed using a modified vision tracking algorithm. For the purpose of model validation, the simulated trajectory is compared to the reconstructed trajectory, resulting in a deviation of only 2.42%. Such high modeling accuracy makes this proposed method an ideal tool for developing the virtual vision systems emulating the games that can be used to train table tennis players efficiently.

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