scholarly journals Experimental studies of electrical noise in the aircraft control system

2020 ◽  
pp. 31-46
Author(s):  
Mykola Chernyak ◽  
Roman Chornomorets
Keyword(s):  
Control System ◽  
Flight Control ◽  
High Speed ◽  
Experimental Studies ◽  
Electrical Equipment ◽  
Satellite System ◽  
Phase Locked Loops ◽  
Electrical Noise ◽  
Clock Signal ◽  
Global Navigation Satellite

Currently, the problem of reducing noise in electrical equipment is important, because a noise in the system affects its components and can cause unpredictable behavior of the electrical system. This is especially important onboard of unmanned aerial vehicle (UAV), where all components are located close to each other and their noise has a significant cross-effect. Conductors passing through a noisy environment can pick up a noise and direct it to another circuits, where it creates interference. Some examples of such noise problems are: degraded accuracy characteristics of microcontroller modules (Analog-to-Digital Converters (ADC), Phase-Locked Loops (PLL) and other) due to noise on supply and reference voltages, wrong acquisition of the digital signals and interference with global navigation satellite system (GNSS) or remote control system of UAV. This article is dedicated to the research of the influence of electrical noise, which is formed by the components of the UAV control system (engines, electric motor controllers, microcontroller etc.), on the performance and noise protection of electronic components of the UAV control system. After the research it was concluded that the main sources of elecrtrical noise in the UAV control system are: high currents, consumed by electronic speed controllers (with motors), high-speed toggling of clock signal of SPI / I2C communication, regulation by step-down voltage regulator and internal processes inside the microcontroller due to work of flight control firmware. The waveforms of generated noises, caused by each source was measured with oscilloscope and depicted in the article.

Design of sliding mode flight control system for a flexible aircraft

2021 ◽  
pp. 095441002110455
Author(s):  
Majeed Mohamed ◽  
Madhavan Gopakumar
Keyword(s):  
Control System ◽  
Rigid Body ◽  
Flight Control ◽  
High Speed ◽  
Sliding Mode ◽  
Flight Mechanics ◽  
Frequency Separation ◽  
Flight Control System ◽  
Flexible Aircraft ◽  
Aircraft Dynamics

The evolution of large transport aircraft is characterized by longer fuselages and larger wingspans, while efforts to decrease the structural weight reduce the structural stiffness. Both effects lead to more flexible aircraft structures with significant aeroelastic coupling between flight mechanics and structural dynamics, especially at high speed, high altitude cruise. The lesser frequency separation between rigid body and flexible modes of flexible aircraft results in a stronger interaction between the flight control system and its structural modes, with higher flexibility effects on aircraft dynamics. Therefore, the design of a flight control law based on the assumption that the aircraft dynamics are rigid is no longer valid for the flexible aircraft. This paper focuses on the design of a flight control system for flexible aircraft described in terms of a rigid body mode and four flexible body modes and whose parameters are assumed to be varying. In this paper, a conditional integral based sliding mode control (SMC) is used for robust tracking control of the pitch angle of the flexible aircraft. The performance of the proposed nonlinear flight control system has been shown through the numerical simulations of the flexible aircraft. Good transient and steady-state performance of a control system are also ensured without suffering from the drawback of control chattering in SMC.

scholarly journals Optimization of parameters for diesel shaft speed control system

2019 ◽  
Vol 140 ◽  
pp. 10003
Author(s):  
Vladimir Markov ◽  
Victor Furman ◽  
Sergey Plakhov ◽  
Bowen Sa
Keyword(s):  
High Pressure ◽  
Control System ◽  
Diesel Engine ◽  
High Speed ◽  
Experimental Studies ◽  
Pi Control ◽  
Control Law ◽  
Acceleration Process ◽  
Natural Oscillations ◽  
Fuel Supply

This work presents a fuel supply electronic control system (model ESUVT.01) developed by Dizelavtomatika (Saratov) for the D50 (6 CHN 31.8/33) locomotive diesel engine manufactured by Penzadieselmash. In this system, the fuel supply process is controlled by a high-speed electro-hydraulic valve installed in the high-pressure line of the fuel system. A set of electrically controlled high pressure fuel pumps (mode 4ETN.03) with electro-hydraulic valves for the diesel was manufactured. This system can also control the engine speed. It was noted that the best quality indicators of the speed regulating process are provided by the PID control law. It was shown that for a diesel with high inertia, it is advisable to use the PI control law. Experimental studies were conducted to assess the influence of structure and parameters of this control system on the dynamic qualities of this diesel engine. The object of bench testing was a 1-PDG4D-type diesel-generator from the above-mentioned diesel engine and MPT-84/39 traction generator. The dependences of the duration of the transient process, the overspeed and the period of natural oscillations of the regulated parameter on the PI controller parameters were obtained. The necessity of optimizing the coefficients of proportional (P) and integral (I) components of the PI control law was confirmed. A method for optimizing the coefficients of proportional and integral components of the PI control law was proposed. The optimized coefficients for the transient acceleration process of the diesel engine according to the locomotive characteristic were obtained.

scholarly journals The Effect of Contextual Variables on Match Performance across Different Playing Positions in Professional Portuguese Soccer Players

2021 ◽  
Vol 18 (10) ◽  
pp. 5175
Author(s):  
Joel Barrera ◽  
Hugo Sarmento ◽  
Filipe Manuel Clemente ◽  
Adam Field ◽  
António J. Figueiredo
Keyword(s):  
Physical Performance ◽  
High Speed ◽  
Satellite System ◽  
Soccer Players ◽  
Physical Demands ◽  
Situational Variables ◽  
All Speeds ◽  
Global Navigation Satellite ◽  
Walking Speeds ◽  
Very High

This study investigated the position-specific physical demands of professional Portuguese players. The effects of situational variables on the physical performance demands were also analysed (match location, match half and match result). Match performance observations were collected using Global Navigation Satellite System devices across 11 matches during a competitive season (2019–2020). Data were analysed according to five playing positions: goalkeepers (n = 11), central defenders (n = 42), wide defenders (n = 31), central midfielders (n = 34), open attackers (n = 28), and centre forwards (n = 14). Central midfield players completed the greatest total distance (10,787 ± 1536 m), while central defenders covered the least distance (9272 ± 455; p < 0.001). Open attackers covered the greatest high and very-high-speed distance (1504 ± 363 m), number of high-speed decelerations per match (11 ± 4) and were the fastest players (30.6 ± 1.5 km/h), along with center forwards (30.6 ± 2.0 km/h), versus all other positions (p < 0.05). Greater distances were performed in teams that were winning (9978 ± 1963 m) or drawing (10,395 ± 875 m) versus losing (9415 ± 2050) p = 0.036 and p = 0.006, respectively. Increases in distance covered at walking speeds were observed during the 2nd half (1574 ± 179 m) compared with the 1st half (1483 ± 176; (p < 0.003). A higher number of decelerations across all speeds were performed in the 1st half (144 ± 39) versus the 2nd half (135 ± 37). The distance covered in home matches (10,206 ± 1926 m) far exceeded away matches (9471 ± 1932 m; p < 0.001). The number of faster accelerations were higher in away (7 ± 5) versus home matches (6 ± 4; p < 0.049). The data demonstrate the different physical demands of each playing position and suggest that situational variables influence physical performance. These findings suggest position-specific physical training is required to condition players for the bespoke demands of each playing position.

scholarly journals Structural Coupling and Whirl-Flutter Stability with Pilot-in-the-Loop

2021 ◽  
Author(s):  
Vincenzo Muscarello ◽  
Giuseppe Quaranta
Keyword(s):  
Control System ◽  
Flight Control ◽  
High Speed ◽  
Sensitivity Analyses ◽  
Critical Parameters ◽  
Flight Control System ◽  
Structural Coupling ◽  
Yaw Control ◽  
Whirl Flutter ◽  
Biodynamic Model

This paper investigates structural coupling problems for tiltrotors, considering not only the interaction of the flight control system with the flexible structure but also the potentially adverse effects on the aeroservoelastic stability that may be caused by the pilot's involuntary, high-frequency, biodynamic response. The investigation is focused on the analysis of the side effects that could appear at high speed in the airplane flight regime, where the whirl flutter boundaries may be significantly reduced. A detailed tiltrotor model, representative of the Bell XV-15 and of a flight control system has been built and joined with a pilot biodynamic model acting on the power-lever and on the center stick, available in the literature. Additionally, a modified version of the XV-15 using differential collective pitch for yaw control in airplane mode instead of rudder has been investigated to show the effect of different yaw control designs.The stability analyses presented demonstrate that the structural coupling analysis and the flutter boundaries for tiltrotors must be evaluated not only considering the closed loop created by the flight control system but also the effect of involuntary pilot response. Sensitivity analyses examine the most critical parameters impacting tiltrotor aeroservoelastic stability. Finally, the employment of notch filters as a means of prevention is discussed.

scholarly journals Investigation of method of elimination of interference situation effect on GPS navigation receiver operation by smoothing of pseudorange measurements by pseudophase increment

2020 ◽  
pp. 46-53
Author(s):  
V. Y. Vovasov ◽  
D. A. Sukharev
Keyword(s):  
High Precision ◽  
Experimental Studies ◽  
Satellite System ◽  
Mobile Object ◽  
Time Interval ◽  
Urgent Task ◽  
Long Time ◽  
The Difference ◽  
Navigation Signals ◽  
Global Navigation Satellite

The wide application of high-precision GNSS (global navigation satellite system) positioning technologies for unmanned mobile object management requires the acquisition of solutions with subdecimeter accuracy and the reduction of the convergence period to such accuracy from the beginning of measurements to 20–25 minutes. Unfortunately, the accuracy of the obtained navigation solutions and the time of convergence to high-precision solutions are influenced by re-reflection of GNSS signals from the ground, buildings and structures, as well as interference from different sources of radio emissions of the urban environment. Therefore, it is an urgent task to implement methods of eliminating the influence of the interference situation on the operation of the navigation receiver of GNSS signals and investigating their effectiveness. The paper considers the results of investigation of the method of elimination of interference situation effect on GPS signal navigation receiver operation using smoothing of raw pseudorange measurements by pseudophase increment. Justification of the difference of measurement of pseudo-range by carrier phase and pseudo-range by code is given as a criterion of efficiency of estimation of interference situation influence in the area of navigation signals reception. As a result of the analysis of experimental studies, it has been shown that using the described method, starting from 900 seconds, the values of the smoothed parameter do not deviate from the averaged measurements over a long time interval by more than 0.1 meters, which indicates the efficiency of the method of smoothing by phase increments and is potentially promising for highly accurate measurements.

Designing a Control Failure Survival System for High Speed Transport Aircraft Using Eigenvalue Assignment Method

2012 ◽  
Author(s):  
Zairil A. Zaludin
Keyword(s):  
Control System ◽  
Flight Control ◽  
High Speed ◽  
Control Surface ◽  
Longitudinal Motion ◽  
State Variables ◽  
Flight Control System ◽  
Short Period ◽  
Control Failure ◽  
Eigenvalue Assignment

Jika kerosakan berlaku kepada permukaan kawalan penerbangan, tujuan “Sistem Pereka Bentuk Kawalan Penerbangan” ialah untuk membahagi dan menyelaras usaha kawalan antara permukaan-permukaan kawalan yang masih aktif untuk tujuan mengekalkan mutu penerbangan yang diingini. Tugas utama ‘Sistem Pereka Bentuk Kawalan Penerbangan’ adalah untuk menyelaraskan unit kawalan semasa kerosakan berlaku ataupun menukar unit kawalan kepada sistem kawalan yang lebih sesuai untuk tujuan membaiki kerosakan tersebut. Dalam kertas ini, cara yang kedua dipertimbangkan. Reka bentuk “Sistem Keselamatan Kegagalan Kawalan” untuk pesawat hipersonik dibentangkan. Cara tersebut adalah berdasarkan cara penetapan nilai eigen dan teori pengatur kuadratik linear. Terdapat tiga masukan kawalan ke pesawat tersebut. Jika cara yang dibentangkan di dalam kertas ini digunakan, keputusan analisis yang dibentangkan menunjukkan bahawa sistem kawalan penerbangan untuk pesawat ini boleh direka bentuk sehingga kestabilan pesawat tersebut dicapai semula apabila salah satu ataupun gabungan permukaan kawalan gagal berfungsi pada masa yang sama. Didapati juga gerakan tabii pesawat yang mengalami kerosakan dapat dibaik pulih seperti sebelum kerosakan berlaku. Satu contoh disertakan dalam kertas ini menggunakan model matematik pesawat hipersonik. Kata kunci: dinamik penerbangan; penerbangan hipersonik; kawalan optimal; penetapan nilai eigen; Teori LQR In the event of a control surface failure, the purpose of a reconfigurable flight control system is to redistribute and coordinate the control effort among the aircraft’s remaining effective surfaces such that satisfactory flight performance is retained. A major task in control reconfiguration deals with adjusting the controller gains on-line or switching to a different control law to compensate for the failure. In this paper, the former option is considered. The design of a Control Failure Survival System (CFSS) for a hypersonic transport (HST) aircraft is presented. The method is based on eigenvalue assignment which was developed using Linear Quadratic Regulator theory. There are three control inputs available on board the HST; the change in the flaps deflection, the change in the propulsion diffuser area ratio and the change in the total temperature across combustor. Using the method discussed in this paper, the results showed that it was possible to reconfigure the flight control system such that the aircraft stability is regained when either a single or a combination of, control failures occurred simultaneously. In addition, the natural motion characteristics (i.e short period, phugoid and height motion) of the aircraft before the failure occurred are conserved and the transient response of the aircraft state variables after failure was almost the same as before failure occurred. An example is included in this paper using the mathematical model of the longitudinal motion of the HST. Key words: Aircraft dynamics; hypersonic flight; optimal control; eigen value assignment; LQR Theory

scholarly journals Simulating actuator energy consumption for trajectory optimisation

2017 ◽  
Vol 232 (11) ◽  
pp. 2178-2192
Author(s):  
Michael Cooper ◽  
Craig Lawson ◽  
Amir Zare Shahneh
Keyword(s):  
Control System ◽  
Flight Control ◽  
High Speed ◽  
Electrical Energy ◽  
Guidance System ◽  
Control Surface ◽  
Aerodynamic Load ◽  
Actuation System ◽  
Heading Control ◽  
Trajectory Optimisation

This work aims to construct a high-speed simulation tool which is used to quantify the dynamic actuator power consumption of an aircraft in flight, for use within trajectory optimisation packages. The purpose is to evaluate the energy penalties of the flight control actuation system as an aircraft manoeuvre along any arbitrary trajectory. The advantage is that the approximations include major transient properties which previous steady state techniques could not capture. The output can be used to provide feedback to a trajectory optimisation process to help it compute the aircraft level optimality of any given flight path. The tool features a six degree of freedom dynamic model of an aircraft which is combined with low frequency functional electro-mechanical actuator models in order to estimate the major transient power demands. The actuator models interact with the aircraft using an aerodynamic load estimator which generates load forces on the actuators that vary as a function of flight condition and control surface demands. A total energy control system is applied for longitudinal control and a total heading control system is implemented to manage the lateral motion. The outer loop is closed using a simple waypoint following guidance system with turn anticipation and variable turn radius control. To test the model, a simple trajectory analysis is undertaken which quantifies a heading change executed with four different turn rates. The tool shows that the actuation system requires 12.8 times more electrical energy when performing a 90° turn with a radius of 400 m compared to 1000 m. A second test is performed to verify the model’s ability to track a longer trajectory under windy conditions.

scholarly journals A New Avionics-Based GNSS Integrity Augmentation System: Part 1 – Fundamentals

2013 ◽  
Vol 66 (3) ◽  
pp. 363-384 ◽  
Author(s):  
Roberto Sabatini ◽  
Terry Moore ◽  
Chris Hill
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Multipath Fading ◽  
Satellite System ◽  
Safety Critical ◽  
Research Activities ◽  
Aerial Vehicle ◽  
System Part ◽  
Global Navigation Satellite ◽  
Gnss Data

The aviation community has very stringent navigation integrity requirements that apply to a variety of manned and Unmanned Aerial Vehicle (UAV) operational tasks. This paper presents the results of the research activities carried out by the Italian Air Force Flight Test Centre (CSV-RSV) in collaboration with the Nottingham Geospatial Institute (NGI) and Cranfield University (CU) in the area of Avionics-Based Integrity Augmentation (ABIA) for mission- and safety-critical Global Navigation Satellite System (GNSS) applications. Based on these activities, suitable models were developed to describe the main causes of GNSS signal outage and degradation in flight, namely: antenna obscuration, multipath, fading due to adverse geometry and Doppler shift. Adopting these models in association with suitable integrity thresholds and guidance algorithms, the ABIA system delivers integrity caution (predictive) and warning (reactive) flags, as well as steering information to the pilot and electronic commands to the aircraft/UAV flight control system. These features allow real-time avoidance of safety-critical flight conditions and fast recovery of the required navigation performance in case of GNSS data losses. This paper presents the key ABIA concepts, architecture and mathematical models. A successive paper will address the ABIA integrity thresholds criteria and detailed results of a TORNADO simulation case-study.

Helicopter load alleviation using active control

2008 ◽  
Vol 112 (1137) ◽  
pp. 663-672
Author(s):  
M. Voskuijl ◽  
D. J. Walker ◽  
B. J. Manimala
Keyword(s):  
Control System ◽  
Flight Control ◽  
High Speed ◽  
Flight Control System ◽  
Order Model ◽  
Longitudinal Control ◽  
Handling Qualities ◽  
Control Techniques ◽  
Maneuvering Flight

Abstract This paper discusses how structural load objectives can be included in a rotorcraft flight control system design in an efficient and straightforward way using multivariable control techniques. Several research studies have indicated that pitch link loads for various rotorcraft types can reach high or even unacceptable values, both in steady state and maneuvering flight. This is especially the case for high-speed aggressive maneouvers. Pitch link loads at high-speed flight are therefore taken as a case study. A novel longitudinal control system is presented, designed to reduce helicopter pitch-link loads during high-speed longitudinal manoeuvres whilst providing a pitch attitude command attitude hold response type. The design is based on a high-order model of a helicopter representative of the UH-60 Black Hawk. New metrics are presented for the analysis of structural loads that can be used in combination with ADS-33 handling qualities requirements.

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