Two methods for improved accuracy calibration and control of ion implanter incidence angle

2003 ◽  
Author(s):  
R.D. Elzer ◽  
P. Oakey ◽  
J. Chen ◽  
D. Sing
Keyword(s):  
Incidence Angle ◽  
And Control ◽  
Improved Accuracy

scholarly journals Automated Measurement and Control of Germination Paper Water Content

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2232
Author(s):  
Lina Owino ◽  
Marvin Hilkens ◽  
Friederike Kögler ◽  
Dirk Söffker
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Plant Development ◽  
Growth Substrate ◽  
Irrigation Amount ◽  
Control Approach ◽  
Predictive Controller ◽  
And Control ◽  
Improved Accuracy ◽  
Measurement And Control

Germination paper (GP) is used as a growth substrate in plant development studies. Current studies bear two limitations: (1) The actual GP water content and variations in GP water content are neglected. (2) Existing irrigation methods either maintain the GP water content at fully sufficient or at a constant deficit. Variation of the intensity of water deficit over time for plants grown on GP is not directly achievable using these methods. In this contribution, a new measurement and control approach was presented. As a first step, a more precise measurement of water content was realized by employing the discharging process of capacitors to determine the electrical resistance of GP, which is related to the water content. A Kalman filter using an evapotranspiration model in combination with experimental data was used to refine the measurements, serving as the input for a model predictive controller (MPC). The MPC was used to improve the dynamics of the irrigation amount to more precisely achieve the required water content for regulated water uptake in plant studies. This is important in studies involving deficit irrigation. The novel method described was capable of increasing the accuracy of GP water content control. As a first step, the measurement system achieved an improved accuracy of 0.22 g/g. The application of a MPC for water content control based on the improved measurement results in an overall control accuracy was 0.09 g/g. This method offers a new approach, allowing the use of GP for studies with varying water content. This addressed the limitations of existing plant growth studies and allowed the prospection of dependencies between dynamic water deficit and plant development using GP as a growth substrate for research studies.

Flight mechanics of a free-wing tilt-body aircraft

2008 ◽  
Vol 112 (1137) ◽  
pp. 625-640
Author(s):  
K. Ro ◽  
J. W. Kamman ◽  
J. B. Barlow
Keyword(s):  
Mathematical Model ◽  
Incidence Angle ◽  
Equations Of Motion ◽  
Dynamic Modelling ◽  
Flight Simulation ◽  
The Body ◽  
Flight Mechanics ◽  
Short Takeoff And Landing ◽  
And Control ◽  
The Mathematical Model

Abstract The free-wing tilt-body aircraft refers to a vehicle configuration in which the wing, fuselage, and empennage are in a longitudinally articulated connection. This allows the main wing to freely rotate relative to the body, while the empennage, which is in the form of a long twin boom connected to the rear of the body, changes its incidence angle relative to the body in response to external commands. The principal advantages claimed for the configuration are short takeoff and landing capability, and reduced gust sensitivity. The aerodynamics of the free-wing tilt-body configuration has been previously studied, but analysis of its flight mechanics is limited. In this paper we present derivations of the flight dynamic equations of motion using multi-body dynamic modelling techniques, and combine the resulting equations of motion with experimental aerodynamic data to achieve a nonlinear mathematical model for flight simulation of a generic free-wing tilt-body vehicle. The mathematical model is suitable for the study of detailed dynamic characteristics as well as for model based control law synthesis. Key flight performance, and stability and control characteristics of a generic configuration are obtained from the mathematical model.

scholarly journals Modulation and Control Technology for Generating Movable Super-Diffraction Optical Needle by Oblique Incidence

2020 ◽  
Vol 10 (15) ◽  
pp. 5237
Author(s):  
Simo Wang ◽  
Siyang Yu ◽  
Fanxing Li ◽  
Fuping Peng ◽  
Jialin Du ◽  
...  
Keyword(s):  
High Resolution ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Laser Processing ◽  
Oblique Incidence ◽  
Incidence Angle ◽  
Scanning System ◽  
Control Technology ◽  
Depth Of Focus ◽  
And Control

The movable super-diffraction optical needle (MSON) is a tightly focused beam like a “needle”, which can realize vector scanning on the focusing plane. Not only does it have a long focal depth, but its resolution also exceeds the diffraction limit. The modulation and control technology required for generating MSON by oblique incidence is explored in this manuscript for the purpose of processing high-aspect-ratio, sub-wavelength structures. As the optical needle generated by traditional methods is static and sensitive to variation of the angle information of the incident beam, here we introduce a confocal scanning system by using a two-dimensional galvanometer system, a scan lens, and a tube lens to control the oblique incidence angle. The effects of the oblique incidence angle on the resolution, depth of focus, uniformity, and side lobes of the MSON were analyzed. Further, the voltage-controlled liquid crystal located between the scan lens and the 2D galvanometer system can be used to compensate for the additional phase difference caused by oblique incidence. The aspect ratio is defined as the ratio of depth of focus to resolution. By modulating and controlling the light field, the MSON with high aspect ratio (7.36), sub-diffractive beam size (0.42λ), and long depth of focus (3.09λ) has been obtained with homogeneous intensity, and suppressed side lobes. High speed, high axial positioning tolerance, and high-resolution laser processing can also be achieved, which removes the restrictions presented by traditional laser processing technology, for which high resolution and long depth of focus cannot be achieved simultaneously.

Experimental Validation of a Dynamic Model (Equivalent Rigid Link System) on a Single-Link Flexible Manipulator

1989 ◽  
Vol 111 (4) ◽  
pp. 667-672 ◽  
Author(s):  
R. P. Petroka ◽  
Liang-Wey Chang
Keyword(s):  
Dynamic Model ◽  
Robot Manipulator ◽  
Flexible Manipulator ◽  
Flexible Manipulators ◽  
Rigid Link ◽  
Future Design ◽  
Single Link ◽  
Manipulator Design ◽  
And Control ◽  
Improved Accuracy

Flexibility effects on robot manipulator design and control are typically ignored which is justified when large, bulky robotic mechanisms are moved at slow speeds. However, when increased speed and improved accuracy are desired in robot system performance it is necessary to consider flexible manipulators. This paper simulates the motion of a single-link, flexible manipulator using the Equivalent Rigid Link System (ERLS) dynamic model and experimentally validates the computer simulation results. Validation of the flexible manipulator dynamic model is necessary to ensure confidence of the model for use in future design and control applications of flexible manipulators.

scholarly journals DL-IPS: Deep Learning Based Indoor Positioning System for Improved Accuracy

2019 ◽  
Vol 8 (4) ◽  
pp. 10797-10801
Keyword(s):  
Deep Learning ◽  
Low Cost ◽  
Signal Strength ◽  
Low Energy ◽  
Positioning System ◽  
Received Signal Strength Indicator ◽  
Indoor Tracking ◽  
And Control ◽  
Improved Accuracy ◽  
Indoor Positioning System

Indoor tracking has evolved with various methods and well known these days. There are diverse types of solutions that concentrate on exactness, low cost, and control utilization within the field. Particularly in recent years, Received Signal Strength Indicator based positioning estimation have been getting popular. Still, the accuracy are not adequate, and there's no correct way chosen to overcome this issue. In this paper, we propose a strategy that leverage Deep Learning and Wi-Fi/BLE (Bluetooth Low Energy) Fingerprinting strategy to produce superior precise accuracy.

Characterization Improvement Through Signal Processing: Application to Radiography Inspection — 3D Reconstruction

2005 ◽  
Author(s):  
Laurence Chatellier ◽  
Valery E. Just ◽  
Louis Fournier ◽  
Bruno Charbonnier ◽  
Lionel Robillard
Keyword(s):  
Signal Processing ◽  
3D Reconstruction ◽  
Incidence Angle ◽  
Vertical Direction ◽  
Regulatory Requirements ◽  
Reconstruction Process ◽  
Processing Application ◽  
Improved Accuracy ◽  
Service Inspection

During in-service inspections, experts are faced with the delicate task of establishing a complete diagnosis of defects from radiographs. Should a defect be detected, one must be able to demonstrate that the component still meets regulatory requirements. Thus, it is essential to be able to characterize precisely the defect, especially when the demonstration relies on mechanical calculus. However the characterization of the defect by only g or X-ray is sometimes very difficult, and the justification process can thus be jeopardized. In such cases, signal processing can be very helpful for the interpretation of the data and for the characterization (positioning and sizing) of the defect. This paper presents a 3-D reconstruction processing in hard conditions representatives of pipe inspections: the incidence angle is very reduced and thus the radiographs contain very little information along the vertical direction. The reconstruction process relies on the estimation of the attenuation. It is called inversion because it restores the attenuation from both data and prior information. The method has been tested on radiographs of a block with real defects and the performances were evaluated from a mock-up with several electro-drilled cylindrical defects. Even in the case of limited incidence, the method provides very useful 3D results. Moreover this process can be applied whatever the nature of the source. When a larger source is used in order to inspect thick components, signal processing allows to reduce the inevitable blur which leads to improved accuracy. In conclusion, signal processing and especially 3D reconstruction in the case of radiography can turn out to be a key step fur in-service inspection of major NPP components.

New Pneumatic Cylinders for Improving Servo Actuator Positioning Accuracy

2004 ◽  
Vol 126 (4) ◽  
pp. 744-747 ◽  
Author(s):  
Igor L. Krivts
Keyword(s):  
Control System ◽  
Friction Force ◽  
Pneumatic Cylinder ◽  
Experimental Examination ◽  
Positioning Accuracy ◽  
Servo Actuator ◽  
And Control ◽  
Improved Accuracy ◽  
Accuracy Performance ◽  
Pneumatic Cylinders

Positioning accuracy of pneumatic servo actuators depends on parameters of the actuator and control system, and also on the friction force. This paper reports on new constructions of the pneumatic cylinders, which are the integral part of the servo actuator. Experimental examination of these servo actuators has shown that they could provide improved accuracy performance over the system with ordinary pneumatic cylinder.

scholarly journals Improved Accuracy of a Single-Slit Digital Sun Sensor Design for CubeSat Application Using Sub-Pixel Interpolation

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1472
Author(s):  
Fuat Kaan Diriker ◽  
Alexander Frias ◽  
Ki Hwan Keum ◽  
Regina S. K. Lee
Keyword(s):  
Sun Sensor ◽  
Simple Geometry ◽  
Lower Accuracy ◽  
Mask Design ◽  
Slit Size ◽  
Micro Systems ◽  
And Control ◽  
Improved Accuracy ◽  
Pixel Interpolation ◽  
Better Than

In recent years, we have seen significant improvements in the digital sun sensor (DSS) design enabled by advanced micro-systems fabrication and optical sensing technologies. In this paper, we propose a simple single-slit DSS concept with improved accuracy using sub-pixel interpolation. In considering the DSS design, we focused on several characteristics of the sun sensor, including field-of-view, sensor accuracy, complexity, and computational requirements. First, the optimal mask design was determined based on the simple geometry of the slit size, mask height and pixel width. Then, a two-step pixel read-out algorithm was implemented for sub-pixel level interpolation to determine the illumination ratio using 1-, 2-, 4- and 8-bit readouts. Lastly, the improved DSS was integrated with typical CubeSat, commercial-grade attitude sensors suite and a simple TRIAD method to determine the attitude of a CubeSat in LEO. Compared to standard 1-bit read-out mode (0.32 deg RMSE), 8-bit DSS achieves better than 0.01 deg RMSE. In a CubeSat scenario, improvements in attitude knowledge and control accuracy are marginal when using TRIAD, due to the significantly lower accuracy in other CubeSat-scale sensors (magnetometer, for example).

Loran-C Chain and UTC Synchronisation

2000 ◽  
Vol 53 (2) ◽  
pp. 215-223
Author(s):  
William F. Roland
Keyword(s):  
Time Management ◽  
Service Providers ◽  
Digital Signal ◽  
Timing Control ◽  
Control Techniques ◽  
Timing Information ◽  
History Of ◽  
And Control ◽  
Improved Accuracy ◽  
Measurement And Control

There has been much discussion recently implying that Loran-C chain synchronisation using ‘System Area Monitor’ (SAM) control and using ‘Time of Transmission (or Emission)’ (TOT or TOE) are incompatible mechanisations of Loran-C chain time management because of their differing impact on users. Further, the mechanisation of UTC synchronisation is described as either satellite (GPS/GLONASS) based or Loran Chain measurement based, thereby excluding integrated use of both techniques for reliability. These differences are not mutually exclusive. Well-defined chain synchronisation can logically apply all measurement and control techniques as well as providing improved accuracy. This paper defines synchronisation and describes the history of Loran-C synchronisation control and the current methods employed. The existence of Cesium Standards at Loran stations, and the recent introduction of digital signal processing receivers, have greatly changed the potential for extremely precise timing control, detection of extraordinary timing changes, and the maintenance of very tight UTC synchronisation. This paper describes a number of techniques for defining, observing and applying the various sources of timing information, optimising performance for users and simplifying implementation for service providers.

scholarly journals Belt Conveyor Dynamic Characteristics and Influential Factors

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Junxia Li ◽  
Xiaoxu Pang
Keyword(s):  
Control Strategy ◽  
Longitudinal Vibration ◽  
Viscoelastic Model ◽  
Influential Factors ◽  
Belt Conveyor ◽  
Continuity Equations ◽  
Belt Conveyors ◽  
Continuous Dynamic ◽  
And Control ◽  
Improved Accuracy

This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed approach provides improved accuracy for dynamic design of belt conveyors.

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