Application of Optimal Kalman Filter to Improve the Accuracy of Aircraft Wing Vibration Parameters Measurement System

This paper discusses the advantages of constructing a vibration parameters measurement system of an aircraft wing using mems IMUs. In addition to mems IMUs, the system makes use of displacement sensor and navigation system as secondary measurements, along with the optimal Kalman filter estimation. The basic principles of system operation are described. The main algorithms of the system and its errors mathematical model are presented. The results of simulation are presented, demonstrating the expected measurement accuracy of the system as a whole.

Improved Grey Particle Swarm Optimization and New Luus-Jaakola Hybrid Algorithm Optimized IMC-PID Controller for Diverse Wing Vibration Systems

The PID control plays important role in wing vibration control systems. However, how to efficiently optimize the PID parameters for different kinds of wing vibration systems is still an open issue for control designers. The problem of PID control optimization is first converted into internal mode control based PID (IMC-PID) parameters optimization problem for complex wing vibration systems. To solve this problem, a novel optimization technique, called GNPSO is proposed based on the hybridization of improved grey particle swarm optimization (GPSO) and new Luus-Jaakola algorithm (NLJ). The original GPSO is modified by using small population size/iteration number, employing new grey analysis rule and designing new updating formula of acceleration coefficients. The hybrid GNPSO benefits improved global exploration of GPSO and strong local search of new Luus-Jaakola (NLJ), so as to avoid arbitrary and inefficient search of global optimum and prevent the trap in local optimum. Diverse wing vibration systems, including linear system, nonlinear system and multiple-input-multiple-output system are considered to verify the effectiveness of proposed method. Simulation results show that GNPSO optimized method obtains improved vibration control performance, stronger robustness and wide applicability on all system cases, compared to existing evolutionary algorithm based tuning methods. Enhanced optimization convergence and computation efficiency obtained by GNPSO tuning technique are also verified by statistical analysis.

OPTICAL RESEARCH OF THE PECULIARITIES OF THE FLOW AROUND MODELS WITH LOCAL SUPERSONIC ZONES IN INDUSTRIAL ADT T – 128

The paper discusses the results of the effective application of the method of spatial visualization of the flow around models in industrial ADT T - 128, combined with standard weight tests. Visualization of flow over the model was performed by varying humidity and temperature of the flow in test section. The results of a consistent standard weight experiment and a physical study of the characteristics of the flow around an aerodynamic model in an industrial ADT T - 128 are presented. In standard weight tests using video methods, the complex flow structure arising from the flow around an aerodynamic model at subsonic and transonic speeds is investigated. The results of balance measurements with simultaneous application of the method of spatial flow visualization around model in industrial T - 128 wind tunnel allowed to obtain physical information on the flow structure - a shock-waves, flow separation, wing vibration and deformation, the onset of asymmetric vortices. This greatly allows to expand the information content of experimental studies, to increase their reliability and to give a correct interpretation of the results obtained.

Vibrational behavior of psyllids (Hemiptera: Psylloidea): functional morphology and mechanisms

Vibrational behavior of psyllids was first documented more than six decades ago. Over the years, workers have postulated as to what the exact signal-producing mechanisms of psyllids might be but the exact mechanism has remained elusive. The aim of this study is to determine the specific signal-producing structures and mechanisms of the psyllids. Here we examine six hypotheses of signal-producing mechanisms from both previous and current studies that include: wing vibration, wing-wing friction, wing-thorax friction, wing-leg friction, leg-abdomen friction, and axillary sclerite-thorax friction. Through selective removal of possible signal producing structures and observing wing-beat frequency with a high-speed video recorder, six hypotheses were tested. Extensive experiments were implemented on the species Macrohomotoma gladiata Kuwayama, while other species belonging to different families, i.e., Trioza sozanica (Boselli), Mesohomotoma camphorae Kuwayama, Cacopsylla oluanpiensis (Yang), and Cacopsylla tobirae (Miyatake) were also examined to determine the potential prevalence of each signal-producing mechanism within the Psylloidea. Further, scanning electron microscopy (SEM) was used to examine possible rubbing structures. The result of high speed photography showed that wing-beating frequency did not match the dominant frequency of vibrational signals, resulting in the rejection of wing vibration hypothesis. As for the selective removal experiments, the axillary sclerite-thorax friction hypothesis is accepted and wing-thorax friction hypothesis is supported partially, while others are rejected. The SEM showed that the secondary axillary sclerite of forewing bears many protuberances that would be suitable for stridulation. In conclusion, the signal-producing mechanism of psyllids involves two sets of morphological structures. The first is stridulation between the axillary cord and anal area of the forewing. The second is stridulation between the axillary sclerite of the forewing and the mesothorax.

Discovery of a new song mode in Drosophila reveals hidden structure in the sensory and neural drivers of behavior

SummaryDeciphering how brains generate behavior depends critically on an accurate description of behavior. If distinct behaviors are lumped together, separate modes of brain activity can be wrongly attributed to the same behavior. Alternatively, if a single behavior is split into two, the same neural activity can appear to produce different behaviors [1]. Here, we address this issue in the context of acoustic communication in Drosophila. During courtship, males utilize wing vibration to generate time-varying songs, and females evaluate songs to inform mating decisions [2-4]. Drosophila melanogaster song was thought for 50 years to consist of only two modes, sine and pulse, but using new unsupervised classification methods on large datasets of song recordings, we now establish the existence of at least three song modes: two distinct, evolutionary conserved pulse types, along with a single sine mode. We show how this seemingly subtle distinction profoundly affects our interpretation of the mechanisms underlying song production, perception and evolution. Specifically, we show that sensory feedback from the female influences the probability of producing each song mode and that male song mode choice affects female responses and contributes to modulating his song amplitude with distance [5]. At the neural level, we demonstrate how the activity of three separate neuron types within the fly’s song pathway differentially affect the probability of producing each song mode. Our results highlight the importance of carefully segmenting behavior to accurately map the underlying sensory, neural, and genetic mechanisms.

A time-space synchronized fluid-structure coupling algorithm for the prediction of wing flutter

A fast dynamic mesh technology by our research group has been applied in the time synchronized fluid-structure coupling. It is found that flow mesh update after the convergent calculation of the flow will induce excessive iterations in the computation of flow increasing the computing time of fluid-structure coupling. To reduce the computing time, a time-space synchronized fluid-structure coupling algorithm was developed in this paper based on the pre-existing time synchronized method and the fast dynamic mesh technology. The wing vibration and flow mesh deformation were computed using the fast dynamic mesh technology after each iteration in the calculation of the flow. Namely, the flow and the wing vibration were solved in space synchronization. The calculating convergence of the flow and the wing vibration were both achieved through iterations every time step. Namely, the flow and the wing vibration were solved in time synchronization. Thus, the flow and the wing vibration are coupled both in time and space synchronization. The flutter boundary of wing 445.6 was predicted using the present algorithm. The calculated results compare well with the experimental data and the computing time was almost reduced by 75%.

An energy method for flutter analysis of wing using one-way fluid structure coupling

In this paper, an energy method for flutter analysis of wing using one-way fluid structure coupling was developed. To consider the effect of wing vibration, Reynolds-averaged Navier–Stokes equations based on the arbitrary Lagrangian Eulerian coordinates were employed to model the flow. The flow mesh was updated using a fast dynamic mesh technology proposed by our research group. The pressure was calculated by solving the Reynolds-averaged Navier–Stokes equations through the SIMPLE algorithm with the updated flow mesh. The aerodynamic force for the wing was computed using the pressure on the wing surface. Then the aerodynamic damping of the wing vibration was computed. Finally, the flutter stability for the wing was decided according to whether the aerodynamic damping was positive or not. Considering the first four modes, the aerodynamic damping for wing 445.6 was calculated using the present method. The results show that the aerodynamic damping of the first mode is lower than the aerodynamic damping of higher order modes. The aerodynamic damping increases with the increase of the mode order. The flutter boundary for wing 445.6 was computed using the aerodynamic damping of the first mode in this paper. The calculated flutter boundary is consistent well with the experimental data.

MODEL MATEMATIKA SEDERHANA REDAMAN GETARAN PADA SAYAP PESAWAT TERBANG

We have known that when the plane encountered turbulence or in a hard landing, the aircraft engine will swing to dampen vibrations of the aircraft wing. Thus, based on rights, this research is investigating and constructing mathematical model of aircraft wing vibration. In this research, we described not only the creation of mathematical models, but also the analysis of the model and its interpretation.