scholarly journals ENGINEERING OF ACOUSTIC TECHNOLOGY FOR UNDERWATER POSITIONING OBJECT

2018 ◽  
Vol 10 (3) ◽  
pp. 629-637
Author(s):  
Billi Rifa Kusumah ◽  
Indra Jaya ◽  
Henry M. Manik ◽  
. Susilohadi
Keyword(s):  
Control System ◽  
Sound Source ◽  
Arrival Time ◽  
Equation Model ◽  
Control Device ◽  
Electromagnetic Signal ◽  
Positioning System ◽  
Underwater Sound ◽  
Underwater Positioning ◽  
The Difference

Underwater Positioning System (UPS) is a system to track the existence of the position of an object by utilizing the arrival time of the signal measurement. On land, the system uses an electromagnetic signal called GPS. However, because it cannot penetrate water effectively, an acoustic signal is used as an alternative. The purpose of this research is to engineer the control system of data acquisition and underwater acoustic device to measure arrival time (TOA) and apply equation model for underwater sound source positioning system. the effective frequency resonance of the transducer and the hydrophone is at a frequency of 6 kHz. The acquisition control device is able to measure the TOA signal with an error on a digital channel smaller than an analog channel. The difference between the TOA values measured by oscilloscope and acquisition control system is caused by inaccuracy of threshold estimates at the receiver's peak detector circuit. The position of the sound source coordinates obtained from the equation model shows the highest difference in depth point (z) compared to points (x) and (y), caused by the equation model used is limited to four hydrophone units forming a horizontal baseline.

Accuracy Considerations in a 3-D Ultrasonic Positioning System Based on the Difference in Time of Flights

2002 ◽  
Vol 124 (4) ◽  
pp. 688-693 ◽  
Author(s):  
Nishant Unnikrishnan ◽  
Probir Kumar Ray ◽  
Ajay Mahajan ◽  
Tsuchin Chu
Keyword(s):  
Precision Measurement ◽  
Autonomous Vehicles ◽  
Vibration Analysis ◽  
Arrival Time ◽  
Wave Theory ◽  
Positioning System ◽  
Multiple Receivers ◽  
Critical Issues ◽  
Measurement Devices ◽  
The Difference

This paper presents a method to improve the accuracy of an ultrasonic 3-D positioning system that uses the differences in the time of flights from a single transmitter to multiple receivers. The paper presents techniques to overcome errors in ultrasonic systems due to critical issues such as misalignment of transducers, changes in the speed of sound, arrival time of signals, etc. Further, the work presented here is not just applicable to ultrasonic systems but to all systems based on wave theory. This work will impact applications in robotics, virtual reality, precision measurement devices and probes, guidance of autonomous vehicles, and vibration analysis.

scholarly journals A Combined Ray Tracing Method for Improving the Precision of the USBL Positioning System in Smart Ocean

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3586 ◽  
Author(s):  
Jian Li ◽  
Qi Gu ◽  
Ying Chen ◽  
Guiqing Sun ◽  
Haocai Huang
Keyword(s):  
Ray Tracing ◽  
Sound Speed ◽  
Acoustic Noise ◽  
Positioning System ◽  
Underwater Sound ◽  
Short Baseline ◽  
Ray Tracing Method ◽  
Tracking Method ◽  
Underwater Positioning ◽  
Tracing Method

The ultra-short baseline positioning system (USBL) has the advantages of flexible application and easy installation, and it plays an extremely important role in the underwater positioning and communication. The error of the USBL in underwater positioning is mainly caused by a ranging error due to ray tracing, a phase difference error of the USBL, and acoustic noise in the underwater communication. Most of these errors are related to the changes in the sound speed during its propagation through the ocean. Therefore, when using the USBL for underwater detection, it is necessary to correct the sound speed profile in the detection area and optimize the ray tracing. Taking into account the actual conditions, this paper aims at correcting the model of underwater sound speed propagation and improving the tracking method of sound lines when the marine environment in the shallow sea area changes. This paper proposes a combined ray tracing method that can adaptively determine whether to use the constant sound speed ray tracing method or the equal gradient ray tracing method. The theoretical analysis and simulation results show that the proposed method can effectively reduce the error of slant distance in USBL compared with the traditional acoustic tracking method and the constant sound speed ray tracing method. The proposed sound ray correction algorithm solves the contradiction between the number of iterations and the reduction of positioning error and has engineering application value.

Effect of Inner and Outer Wheels Driving Force Control on Small Electric Vehicle

2020 ◽  
Vol 17 (4) ◽  
pp. 8246-8254
Author(s):  
K. Shibazaki ◽  
H. Nozaki
Keyword(s):  
Control System ◽  
Angular Velocity ◽  
Electric Vehicle ◽  
Force Constant ◽  
Force Control ◽  
Driving Force ◽  
Vehicle Control ◽  
Steering Angle ◽  
Force Control System ◽  
The Difference

In this study, in order to improve steering stability during turning, we devised an inner and outer wheel driving force control system that is based on the steering angle and steering angular velocity, and verified its effectiveness via running tests. In the driving force control system based on steering angle, the inner wheel driving force is weakened in proportion to the steering angle during a turn, and the difference in driving force is applied to the inner and outer wheels by strengthening the outer wheel driving force. In the driving force control (based on steering angular velocity), the value obtained by multiplying the driving force constant and the steering angular velocity,  that differentiates the driver steering input during turning output as the driving force of the inner and outer wheels. By controlling the driving force of the inner and outer wheels, it reduces the maximum steering angle by 40 deg and it became possible to improve the cornering marginal performance and improve the steering stability at the J-turn. In the pylon slalom it reduces the maximum steering angle by 45 deg and it became possible to improve the responsiveness of the vehicle. Control by steering angle is effective during steady turning, while control by steering angular velocity is effective during sharp turning. The inner and outer wheel driving force control are expected to further improve steering stability.

Ultra Short Baseline (USBL) Calibration for Positioning of Underwater Objects

2019 ◽  
Vol 2 (2) ◽  
pp. 73-85
Author(s):  
Bagus Septyanto ◽  
Dian Nurdiana ◽  
Sitti Ahmiatri Saptari
Keyword(s):  
Acoustic Wave ◽  
Scale Factor ◽  
Positioning System ◽  
Radio Waves ◽  
Short Baseline ◽  
Error Angle ◽  
Satellite Navigation System ◽  
The Earth ◽  
Underwater Positioning ◽  
Radio Signals

In general, surface positioning using a global satellite navigation system (GNSS). Many satellites transmit radio signals to the surface of the earth and it was detected by receiver sensors into a function of position and time. Radio waves really bad when spreading in water. So, the underwater positioning uses acoustic wave. One type of underwater positioning is USBL. USBL is a positioning system based on measuring the distance and angle. Based on distance and angle, the position of the target in cartesian coordinates can be calculated. In practice, the effect of ship movement is one of the factors that determine the accuracy of the USBL system. Ship movements like a pitch, roll, and orientation that are not defined by the receiver could changes the position of the target in X, Y and Z coordinates. USBL calibration is performed to detect an error angle. USBL calibration is done by two methods. In USBL calibration Single Position obtained orientation correction value is 1.13 ̊ and a scale factor is 0.99025. For USBL Quadrant calibration, pitch correction values is -1.05, Roll -0.02 ̊, Orientation 6.82 ̊ and scale factor 0.9934 are obtained. The quadrant calibration results deccrease the level of error position to 0.276 - 0.289m at a depth of 89m and 0.432m - 0.644m at a depth of 76m

Determinants of Control System Design in Divisionalized Firms

2004 ◽  
Vol 79 (3) ◽  
pp. 545-570 ◽  
Author(s):  
Margaret A. Abernethy ◽  
Jan Bouwens ◽  
Laurence van Lent
Keyword(s):  
Control System ◽  
System Design ◽  
Performance Measures ◽  
Simultaneous Equation ◽  
Equation Model ◽  
Control System Design ◽  
Information Asymmetries ◽  
Endogenous Variables ◽  
And Performance ◽  
Using Data

We investigate two determinants of two choices in the control system of divisionalized firms, namely decentralization and use of performance measures. The two determinants are those identified in the literature as important to control system design: (1) information asymmetries between corporate and divisional managers and (2) division interdependencies. We treat decentralization and performance measurement choices as endogenous variables and examine the interrelation among these choices using a simultaneous equation model. Using data from 78 divisions, our results indicate that decentralization is positively related to the level of information asymmetries and negatively to intrafirm interdependencies, while the use of performance measures is affected by the level of interdependencies among divisions within the firm, but not by information asymmetries. We find some evidence that decentralization choice and use of performance measures are complementary.

scholarly journals Intelligent Control Wheelchair Using a New Visual Joystick

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Yassine Rabhi ◽  
Makrem Mrabet ◽  
Farhat Fnaiech
Keyword(s):  
Control System ◽  
Intelligent Control ◽  
Visual Recognition ◽  
Low Cost ◽  
Control Device ◽  
Control Technique ◽  
Hand Gesture ◽  
Functional Rehabilitation ◽  
Number Of Patients ◽  
Real Patients

A new control system of a hand gesture-controlled wheelchair (EWC) is proposed. This smart control device is suitable for a large number of patients who cannot manipulate a standard joystick wheelchair. The movement control system uses a camera fixed on the wheelchair. The patient’s hand movements are recognized using a visual recognition algorithm and artificial intelligence software; the derived corresponding signals are thus used to control the EWC in real time. One of the main features of this control technique is that it allows the patient to drive the wheelchair with a variable speed similar to that of a standard joystick. The designed device “hand gesture-controlled wheelchair” is performed at low cost and has been tested on real patients and exhibits good results. Before testing the proposed control device, we have created a three-dimensional environment simulator to test its performances with extreme security. These tests were performed on real patients with diverse hand pathologies in Mohamed Kassab National Institute of Orthopedics, Physical and Functional Rehabilitation Hospital of Tunis, and the validity of this intelligent control system had been proved.

Curved Exponential Models in Econometrics

1997 ◽  
Vol 13 (6) ◽  
pp. 771-790 ◽  
Author(s):  
Kees Jan van Garderen
Keyword(s):  
Structural Equation ◽  
Equation Model ◽  
Econometric Models ◽  
Demand Systems ◽  
Likelihood Ratios ◽  
Sufficient Statistics ◽  
Sufficient Statistic ◽  
Exponential Models ◽  
Minimal Sufficient Statistic ◽  
The Difference

Curved exponential models have the property that the dimension of the minimal sufficient statistic is larger than the number of parameters in the model. Many econometric models share this feature. The first part of the paper shows that, in fact, econometric models with this property are necessarily curved exponential. A method for constructing an explicit set of minimal sufficient statistics, based on partial scores and likelihood ratios, is given. The difference in dimension between parameterand statistic and the curvature of these models have important consequences for inference. It is not the purpose of this paper to contribute significantly to the theory of curved exponential models, other than to show that the theory applies to many econometric models and to highlight some multivariate aspects. Using the methods developed in the first part, we show that demand systems, the single structural equation model, the seemingly unrelated regressions, and autoregressive models are all curved exponential models.

Limits to the Control of the Human Thumb and Fingers in Flexion and Extension

2010 ◽  
Vol 103 (1) ◽  
pp. 278-289 ◽  
Author(s):  
W. S. Yu ◽  
H. van Duinen ◽  
S. C. Gandevia
Keyword(s):  
Control System ◽  
Healthy Subjects ◽  
Neural Control ◽  
Force Production ◽  
Total Force ◽  
Neural Drive ◽  
Antagonist Muscles ◽  
Hand Performance ◽  
The Difference ◽  
Flexion And Extension

In humans, hand performance has evolved from a crude multidigit grasp to skilled individuated finger movements. However, control of the fingers is not completely independent. Although musculotendinous factors can limit independent movements, constraints in supraspinal control are more important. Most previous studies examined either flexion or extension of the digits. We studied differences in voluntary force production by the five digits, in both flexion and extension tasks. Eleven healthy subjects were instructed either to maximally flex or extend their digits, in all single- and multidigit combinations. They received visual feedback of total force produced by “instructed” digits and had to ignore “noninstructed” digits. Despite attempts to maximally flex or extend instructed digits, subjects rarely generated their “maximal” force, resulting in a “force deficit,” and produced forces with noninstructed digits (“enslavement”). Subjects performed differently in flexion and extension tasks. Enslavement was greater in extension than in flexion tasks ( P = 0.019), whereas the force deficit in multidigit tasks was smaller in extension ( P = 0.035). The difference between flexion and extension in the relationships between the enslavement and force deficit suggests a difference in balance of spillover of neural drive to agonists acting on neighboring digits and focal neural drive to antagonist muscles. An increase in drive to antagonists would lead to more individualized movements. The pattern of force production matches the daily use of the digits. These results reveal a neural control system that preferentially lifts fingers together by extension but allows an individual digit to flex so that the finger pads can explore and grasp.

scholarly journals Performance and style in the work of Olgyay and Olgyay

2014 ◽  
Vol 18 (2) ◽  
pp. 167-176 ◽  
Author(s):  
David Leatherbarrow ◽  
Richard Wesley
Keyword(s):  
Graphical Representation ◽  
Building Design ◽  
The United States ◽  
Energy Performance ◽  
Control Device ◽  
Simulation Software ◽  
Open Architecture ◽  
Form Generation ◽  
The Difference ◽  
Building Energy Analysis

The sun control device has to be on the outside of the building, an element of the facade, an element of architecture. And because this device is so important a part of our open architecture, it may develop into as characteristic a form as the Doric column.Victor Olgyay (1910–1970), a Hungarian architect who came to the United States in 1947 with his twin brother and collaborator, Aladár (1910–1963), is best known today as the author of Design with Climate: Bioclimatic Approach to Architectural Regionalism (1963), an important book often referenced in the environmental building design field [1]. As leaders in research in bioclimatic architecture from the early 1950s to the late 1960s, the Olgyay brothers could be considered the ‘fathers’ of contemporary environmental building design. Their research and publications laid the foundation for much of the building simulation software in use today. Other than the difference between working on graph paper and using computer-generated graphics, there is little difference between Autodesk's Ecotect Analysis (simulation and building energy analysis software) and the Olgyays' techniques for the analysis of environmental factors and graphical representation of climate. The manner in which the Olgyays established connections between building design and the science of climate laid the foundation for the development of environmental simulation, one of contemporary architecture's leading methods of form generation. Victor Olgyay's teaching, however, represents another kind of thinking, a broader concern for architecture, beyond energy performance. ‘The primary task of architecture,’ Olgyay announced to his students, ‘is to act in man's favour; to interpose itself between man and his natural surroundings in order to remove the environmental load from his shoulders.

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