Experimental assessment of the dynamic stiffness of a fault-tolerant fly-by-wire hydraulic actuator

2012 ◽  
Vol 226 (6) ◽  
pp. 679-690 ◽  
Author(s):  
G Di Rito ◽  
R Galatolo
Keyword(s):  
High Speed ◽  
High Performance ◽  
Position Control ◽  
Fault Tolerant ◽  
Dynamic Stiffness ◽  
Feasibility Studies ◽  
Hydraulic Actuator ◽  
Dynamic Interactions ◽  
Flight Controls ◽  
Vibration Tests

The stiffness of an actuator depends on the closed-loop position control (architecture and parameters), on the load frequency, and, for fault-tolerant actuators, on the operative mode. The stiffness response is of basic importance for the design of actuators for primary flight controls, especially for high-performance aircrafts. Actually, during flight conditions characterized by high speed and high angle-of-attack, the dynamic interactions between aircraft structure, actuator, and aerodynamic loads can induce aeroservoelastic effects, which, if not controlled, can imply performance degradation and even instability. The study and the compensation of such concerns require the assessment of the resonant frequencies of the aeroservoelastic system, which can be performed only by characterizing the dynamic stiffness of the actuator. This article reports the experimental activities carried out for the characterization of the stiffness response of a fault-tolerant fly-by-wire actuator for the primary flight controls of a modern jet trainer, starting from the feasibility studies of the experiments up to the execution of the vibration tests. The actuator stiffness performance is evaluated in different fail-operative modes by artificially injecting hydraulic and electrical failures, and the experimental data are interpreted by means of an LTI model of the flight actuator, highlighting and discussing the effects that the failures induce on the stiffness performance.

Quantitative Fault Tolerant Control Design for a Leaking Hydraulic Actuator

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Mark Karpenko ◽  
Nariman Sepehri
Keyword(s):  
High Performance ◽  
Closed Loop ◽  
Position Control ◽  
Fault Tolerant ◽  
Linear Time ◽  
Fault Tolerant Control ◽  
Variable Load ◽  
Hydraulic Actuator ◽  
Control Approach ◽  
Piston Seal

This paper documents the design of a low-order, fixed-gain, controller that can maintain the positioning performance of an electrohydraulic actuator operating under variable load with a leaking piston seal. A set of linear time-invariant equivalent models of the faulty hydraulic actuator is first established, in the frequency domain, by Fourier transformation of acceptable actuator input-output responses. Then, a robust position control law is synthesized by quantitative feedback theory to meet the prescribed design tolerances on closed-loop stability and reference tracking. The designed fault tolerant controller uses only actuator position as feedback, yet it can accommodate nonlinearities in the hydraulic functions, maintain robustness against typical parametric uncertainties, and maintain the closed-loop performance despite a leakage fault that can bypass up to 40% of the rated servovalve flow across the actuator piston. To demonstrate the utility of the fault tolerant control approach in a realistic application, the experimental fault tolerant hydraulic system is operated as a flight surface actuator in the hardware-in-the-loop simulation of a high-performance jet aircraft.

FPGA-Based Intelligent Software Hardening Chip for Computer Numerical Control System

2011 ◽  
Vol 105-107 ◽  
pp. 2217-2220
Author(s):  
Mu Lan Wang ◽  
Jian Min Zuo ◽  
Kun Liu ◽  
Xing Hua Zhu
Keyword(s):  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Position Control ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Cnc System ◽  
Intelligent Software

In order to meet the development demands for high-speed and high-precision of Computer Numerical Control (CNC) machine tools, the equipped CNC systems begin to employ the technical route of software hardening. Making full use of the advanced performance of Large Scale Integrated Circuits (LSIC), this paper puts forward using Field Programmable Gates Array (FPGA) for the functional modules of CNC system, which is called Intelligent Software Hardening Chip (ISHC). The CNC system architecture with high performance is constructed based on the open system thought and ISHCs. The corresponding programs can be designed with Very high speed integrate circuit Hardware Description Language (VHDL) and downloaded into the FPGA. These hardening modules, including the arithmetic module, contour interpolation module, position control module and so on, demonstrate that the proposed schemes are reasonable and feasibility.

scholarly journals High-Performance and Energy-Efficient Fault Tolerance FPGA-to-FPGA Communication

2021 ◽  
Author(s):  
Naresh Kumar Reddy ◽  
Swamy Cherukuru ◽  
Veena Vani ◽  
Vishal Reddy
Keyword(s):  
Error Detection ◽  
High Speed ◽  
High Performance ◽  
Fault Tolerant ◽  
Key Factors ◽  
Error Detection And Correction ◽  
Performance Error ◽  
Increasing Demand ◽  
Accuracy Performance ◽  
Or Applications

Abstract These days, due to the increasing demand for high speed and parallel computation, several real world applications and systems include multiple FPGAs in them. Due to this, FPGAs often need to communicate among them. So, communication between the FPGAs is one of the key factors that determines the accuracy, performance and correctness of the entire multiple FPGAs systems or applications. This paper presents the design of an efficient multi-bit fault tolerant communication system for FPGA-to-FPGA communication. The proposed design is synthesized and also simulated through Vivado design suit 2018.3 and was communicated with two Kintex-7 FPGA boards. When compared with the existing FPGA-to-FPGA communication and inter FPGA communication designs, the proposed design have higher performance, error detection and correction capability.

scholarly journals Deflection Analysis of the Thin-Web Workpiece Structure Using Similarity Concept

2011 ◽  
Vol 337 ◽  
pp. 479-488
Author(s):  
Nurhaniza Mohamad ◽  
M.K.A.M. Arifin ◽  
Aidy Ali ◽  
Faizal Mustapha
Keyword(s):  
High Speed ◽  
High Performance ◽  
Tool Path ◽  
Dynamic Stiffness ◽  
Cutting Parameters ◽  
High Speed Machining ◽  
Workpiece Vibration ◽  
Deflection Analysis ◽  
Optimum Solution ◽  
Element Removal

The thin-web structure component is widely used in aviation and aerospace industries with the reason of light weight and high performance. However, the thin-web components are tending to deflect because of their poor rigidity and the effect of cutting force during cutting process. It is required to perform of high-speed machining that can remove the large number of material in a shorter time in order to allow machining of such structure. The performance of high-speed machining operation is restricted by the static and dynamic stiffness of the tool and part that can cause some problems such as regenerative chatter and ‘push-off’. The tool path plays an important function to avoid the problem occurs as it assists to reduce the workpiece vibration during machining. The optimization of tool path is done by determining the element removal sequences and the materials removal are implemented using milling cutter. The maximum deflection for each element removed is recorded in order to define the optimum solution of element removal sequences. The analysis shows that there are significant effects of workpiece stiffness with relation to the cutting parameters setting.

scholarly journals Algorithm for Clustering the Moduli of RNS for the Application of Optimization of Time Complexity in Standard Cipher System

2020 ◽  
Vol 9 (7) ◽  
pp. 92-97
Keyword(s):  
High Speed ◽  
High Performance ◽  
Fault Tolerant ◽  
Number System ◽  
Residue Number System ◽  
New Method ◽  
Residue Number ◽  
Residue Numbers ◽  
Performance Computing ◽  
Selection Of

Residue number system (RNS) has emerged as a knocking field of research due to its high speed, fault tolerant, carry free and parallel characteristics. Due to these features it has got important role in high performance computing especially with reduced delay. There are various algorithms have been found as a result of the research with respect to RNS. Additionally, since RNS reduces word length due to the modular operations, its computations are faster compared to binary computations. But the major challenges are the selection of moduli sets for the forward (decimal to residue numbers) and reverse (residue numbers to decimal) conversion. RNS performance is purely depending on how efficiently an algorithm computes / chooses the moduli sets [1]-[6]. This paper proposes new method for selecting the moduli sets and its usage in cryptographic applications based on Schonhage modular factorization. The paper proposes six moduli sets {6qk1, 6qk+1, 6qk+3, 6qk+5, 6qk+7, 6qk+11} for the RNS conversions but the Schonhage moduli sets are expressed as the exponents that creates a large gap between the moduli’s computed. Hence, a new method is proposed to for computing moduli sets that helps in representing all the decomposed values approximately in the same range.

A Magnetic Bearing System for More-Electric Engines

2000 ◽  
Author(s):  
R. Jett Field ◽  
Christopher K. Sortore ◽  
Victor Iannello
Keyword(s):  
High Speed ◽  
High Performance ◽  
Fault Tolerant ◽  
High Reliability ◽  
Industrial Applications ◽  
Magnetic Bearing ◽  
Tip Clearance ◽  
Critical Components ◽  
Maintenance Requirements ◽  
Bearing System

Magnetic bearing systems for more-electric engines (MEEs) are under development for aircraft and industrial applications to improve performance and reduce maintenance requirements. Key features of the magnetic bearing system are high performance, high temperature actuators with integrated sensors; a high speed digital controller; a high reliability, fault-tolerant system architecture; modular amplifiers; active control of tip clearance; and adaptive control algorithms. Critical components of the magnetic bearing system have been demonstrated in an engine manufacturer’s rotordynamic test stand and other components are in various stages of development.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

The bright future of digital imaging in scanning electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 768-769
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Imaging ◽  
High Speed ◽  
High Performance ◽  
Mass Storage ◽  
Analog To Digital ◽  
Central Processing ◽  
Digital Imaging Technology ◽  
Scanning Electron

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

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