Showing papers by "Vaughn College of Aeronautics and Technology published in 2019"
TL;DR: It is proved that, with the proposed strategy, all signals of the closed-loop system are globally uniformly bounded, and the formation tracking error converges to an arbitrarily small residual set.
Abstract: This paper considers the adaptive time-varying formation tracking control of unmanned aerial vehicles (UAVs) with quantized input. Uncertainties and nonholonomic constraint are involved in the UAV model. With a novel transformation of the final control signal, a very coarse quantization can be achieved. Adaptive quantized controllers are proposed by employing backstepping technique. It is proved that, with our proposed strategy, all signals of the closed-loop system are globally uniformly bounded, and the formation tracking error converges to an arbitrarily small residual set. Simulation results are given to illustrate the effectiveness of the proposed strategy.
36 citations
TL;DR: In this paper, the La3+-doped double perovskites were used as anode materials for solid oxide fuel cells, and a crystalline symmetry transition of SLFM from tetragonal to orthorhombic with the increase of La content was revealed.
Abstract: Electron doping in perovskites is an effective approach to design and tailor the structure and property of materials. In A2BB′O6−δ-type double perovskites, B-site cation order can be tunable by A-site modification, potentially leading to significant effect on the oxygen nonstoichiometry of the compounds. La3+-doped Sr2FeMoO6−δ (Sr2−xLaxFeMoO6−δ, SLFM with 0 ≤ x ≤ 1) double perovskites have been designed and characterized systematically in this study as anode materials for solid oxide fuel cells. Rietveld refinement of powder X-ray diffraction reveals a crystalline symmetry transition of SLFM from tetragonal to orthorhombic with the increase of La content, driven by the extra electron onto the antibonding orbitals of eg and t2g of Fe/Mo cations. An increase in Fe/Mo anti-site defect accompanies this phase transition. Solid oxide fuel cells incorporating the Sr1.8La0.2FeMoO6−δ (SLFM2) anode demonstrate impressive power outputs and stable performance under direct CH4 operation because of its altered electronic structure, desired oxygen vacancy concentration and enhanced reducibility. Density functional theory plus U correction calculations provide an insight into how La doping affects the Fe/Mo anti-site defects and consequently the oxygen transport dynamics.
36 citations
TL;DR: The results confirm that heat treatment does reduce the force needed for flake propagation, and demonstrate that such treatment has no significant effect on major morphological aspects of flake form.
Abstract: Intentional heat treating of toolstone has been documented to have begun at least by 70 K BP; however, the advantages of such treatment have been debated for decades. There are two schools of thought with regard to its purpose. One, is that it merely reduces the force required for flake propagation. A second is that it also alters flake morphological properties. We systematically tested these hypotheses by generating flakes from cores exposed to three different temperatures (ambient, 300 °C, and 350 °C) using automated propagation procedures that bypassed any human agency. While the force propagation magnitude is altered by heat treatment, the flakes were not. We examined these flakes according to nine measures of morphology. None differed significantly or systematically within the three categories. While our results confirm that heat treatment does reduce the force needed for flake propagation, they also demonstrate that such treatment has no significant effect on major morphological aspects of flake form.
25 citations
TL;DR: The complete synchronization between the average behaviors of the two oscillators is obtained, and the analytical expression of the output amplitude gain (OAG) is derived and the SR of the coupling system is analyzed based on the analytical results.
24 citations
23 citations
TL;DR: In this article, an adaptive finite-time formation tracking control approach for multiple UAVs with quantized input signals is proposed for multiple unmanned aerial vehicle (UAV) systems.
Abstract: Summary An adaptive finite‐time formation tracking control approach is proposed for multiple unmanned aerial vehicle (UAV) system with quantized input signals in this paper. The UAVs are described ...
22 citations
TL;DR: It is suggested that it was the unusual level of purity in the North American copper sourced by North American groups, and that naturally occurring alloys yielded sufficiently superior tools to encourage entry into the copper-bronze-iron continuum of tool manufacture in other parts of the world.
Abstract: Most prehistoric societies that experimented with copper as a tool raw material eventually abandoned stone as their primary medium for tool making. However, after thousands of years of experimentation with this metal, North American hunter-gatherers abandoned it and returned to the exclusive use of stone. Why? We experimentally confirmed that replica copper tools are inferior to stone ones when each is sourced in the same manner as their archaeological counterparts and subjected to identical tasks. Why, then, did copper consistently lead to more advanced metallurgy in most other areas of the world? We suggest that it was the unusual level of purity in the North American copper sourced by North American groups, and that naturally occurring alloys yielded sufficiently superior tools to encourage entry into the copper-bronze-iron continuum of tool manufacture in other parts of the world.
20 citations
01 Oct 2019
TL;DR: Results show that Trust-repair is effective in restoring trust to a level intermediate between normal and faulty conditions.
Abstract: Swarm robots are coordinated via simple control laws to generate emergent behaviors such as flocking, rendezvous, and deployment. Human-swarm teaming has been widely proposed for scenarios, such as human-supervised teams of unmanned aerial vehicles (UAV) for disaster rescue, UAV and ground vehicle cooperation for building security, and soldier-UAV teaming in combat. Effective cooperation requires an appropriate level of trust, between a human and a swarm. When an UAV swarm is deployed in a real-world environment, its performance is subject to real-world factors, such as system reliability and wind disturbances. Degraded performance of a robot can cause undesired swarm behaviors, decreasing human trust. This loss of trust, in turn, can trigger human intervention in UAVs’ task executions, decreasing cooperation effectiveness if inappropriate. Therefore, to promote effective cooperation we propose and test a trust-repairing method (Trust-repair) restoring performance and human trust in the swarm to an appropriate level by correcting undesired swarm behaviors. Faulty swarms caused by both external and internal factors were simulated to evaluate the performance of the Trust-repair algorithm in repairing swarm performance and restoring human trust. Results show that Trust-repair is effective in restoring trust to a level intermediate between normal and faulty conditions.
19 citations
TL;DR: In this paper, the resonance behavior of two coupled harmonic oscillators with fluctuating mass was studied and the analytical expression of the output amplitude gain was derived by using the stochastic averaging method.
Abstract: This paper studies the resonance behavior in two coupled harmonic oscillators with fluctuating mass. Firstly, the statistic synchronization between the two particles is obtained and defined. Then, the analytical expression of the output amplitude gain is derived by using the stochastic averaging method. Based on the analytical result and some corresponding numerical results, we analyze the coupling’s influence on the resonance behaviors of the output amplitude gain, including the parameter-induced stochastic resonance, the bona fide resonance, and the stochastic resonance. In weak coupling region, the coupling can not only enhance or weaken the resonance behaviors, but also change the resonance forms. In strong coupling region, the two particles are forced together by the coupling force and move synchronously; thus, the coupling’s influence will vanish. Finally, some numerical simulations are performed to provide a verification and an intuitive understanding of the theoretical results.
16 citations
TL;DR: In this paper, NCCR+ was also proposed to include the omitted terms in Myong's simplification, and a coupled solution process based on the time-independent method for non-conserved variables was employed, which is different from the previous uncoupled solution process used for the nonlinear coupled constitutive relations.
Abstract: Generalized hydrodynamic equations were originally proposed to describe the rarefied non-equilibrium flows beyond the Navier–Stokes–Fourier (NSF) equations by constructing a non-equilibrium canonical distribution function for the mesoscopic Boltzmann equation. Subsequently, nonlinear coupled constitutive relations (NCCR) were developed under the adiabatic assumption, the Eu’s closure, and Myong’s simplification. NCCR+ was also proposed to include the omitted terms in Myong’s simplification. The goal of this paper is to assess the improvements in the accuracy due to NCCR+ and the influence of the bulk viscosity in one-dimensional steady shock wave structure for monatomic and diatomic gases. In order to solve NCCR+ equations, a coupled solution process based on the time-independent method for non-conserved variables is employed, which is different from the previous uncoupled solution process used for the NCCR equations. Shock structures in argon and nitrogen are calculated up to Mach 50, where the shock profile, inverse shock thickness, asymmetry parameter, and temperature–density separation distance are validated by DSMC and available experimental measurements. The results show that NCCR+ could not provide much improvement in accuracy compared to NCCR but adds to the computational cost, suggesting that Myong’s simplification used in NCCR is satisfactory. Both NCCR and NCCR+ perform better than NSF in computing the one-dimensional shock wave structure at high Mach numbers. It is also shown that the bulk viscosity has significant influence on the accuracy of prediction of the shock wave structure in a diatomic gas using both NSF and NCCR. Stokes’ hypothesis in conventional NSF is valid only for flows in a monatomic gas and for very low Mach number flows in a diatomic gas. Additionally, it is also found that the viscosity exponent s = 0.81 in variable-hard-sphere model provides a good fit with the experimental data for shock wave in argon using NCCR.
15 citations
TL;DR: In this article, a method involving sequential dip-coating, leaching, and co-sintering was developed and applied to fabricate inert substrate-supported microtubular solid oxide fuel cells through acid leaching nickel from the conventional Ni-yttria-stabilized zirconia (YSZ) anode.
TL;DR: In this article, fully bonded plates composed of aluminum plates (381mm in diameter and 1.59mm thick) and commercial epoxy adhesive were tested under shock wave loading, and the influence of the adhesive thickness and Young's modulus on the behavior of the bonded adhesive under shock-wave loading were investigated using an FEM model.
TL;DR: This paper explores an adaptive WOA variant using Gaussian distribution strategies (GDSs), named GDS-WOA, which outperforms other competitors in terms of convergence efficiency and accuracy and is applied to solve the optimal task allocation problem of heterogeneous unmanned combat aerial vehicles (UCAVs).
Abstract: To overcome the defect of whale optimization algorithm (WOA) being easily fallen into local optimum caused by the ill-distribution of solutions, this paper explores an adaptive WOA variant using Gaussian distribution strategies (GDSs), named GDS-WOA. In GDS-WOA, by means of one GDS, named the Gaussian estimation of distribution method, the superior population information is used to evolve the distribution scope and modify the evolution direction. Moreover, an adaptive framework is adopted to integrate the Gaussian estimation of distribution method and WOA together, in which each individual can update its position using Gaussian estimation of distribution method or WOA according to an adaptive probability parameter. When the algorithm falls into stagnation, another GDS, named Gaussian random walk, is activated to enrich the population diversity and help the algorithm get rid of the local optimum. Additionally, the greedy strategy is carried out to select the offspring from the parents and the generated candidates to fully retain the promising solutions. The GDS-WOA is benchmarked on CEC 2014 test suite, and the performance of GDS-WOA is evaluated by comparing with WOA and its promising variant IWOA, as well as other five state-of-the-art evolutionary algorithms, i.e., COA, VCS, CoBiDE, HFPSO and GWO. The statistical results demonstrate that GDS-WOA outperforms other competitors in terms of convergence efficiency and accuracy. Finally, GDS-WOA is applied to solve the optimal task allocation problem of heterogeneous unmanned combat aerial vehicles (UCAVs). To address this constrained real-world optimizing problem efficiently, the mathematical model of heterogeneous UCAVs task allocation is described with the operational effectiveness value as the objective. The validity and practicauility of the model as well as the performance of GDS-WOA for solving constrained optimization problem are demonstrated by the experimental results.
TL;DR: The new radar chart index, which is composed of several popular incomprehensive measures, are presented, and the method of the weight of the each index is calculated based on vector ranking method.
Abstract: Comprehensive measures for the estimation performance evaluation (EPE) has become increasingly prominent. This paper proposed a new radar chart evaluation method to measure the estimation performance. Firstly, the new radar chart index, which is composed of several popular incomprehensive measures, are presented, and the method of the weight of the each index is calculated based on vector ranking method. Secondly, the new comprehensive measures for the EPE is designed according to the fan area and the fan arc length. Finally, two cases study are provided to verify the effectiveness of this method.
TL;DR: The development of new liquid crystalline materials exhibiting interesting properties and phases continues to be an enabling enterprise in the forward march of their successful display and non-display applications as discussed by the authors, which is supported by a large number of companies.
Abstract: Development of new liquid crystalline materials exhibiting interesting properties and phases continues to be an enabling enterprise in the forward march of their successful display and non-display ...
TL;DR: The economic dispatch optimization is implemented using a reduced gradient algorithm to optimize the Operation and Maintenance cost in the islanded mode of the microgrid, achieving the optimal solution by considering the change in wind forecast and battery energy storage profiles.
Abstract: A microgrid, an emerging technology in the electric power systems, has various benefits due to the implementation of distributed energy sources along with the loads. A microgrid utilizing the wind ...
TL;DR: Compared with the unprocessed reverberation speech, the estimation error is reduced, which shows that the proposed algorithm can effectively improve the estimation accuracy of DOA estimation when the received signals are in a reverberant environment.
Abstract: The accuracy performance of traditional direction of arrival (DOA) estimation algorithms is seriously affected by the reverberation. Considering the advantage of the sparse characteristic of speech signal in time-frequency (T-F) domain, this paper presents a new blind DOA estimation method based on integrated deep learning and convolutional non-negative matrix factorization (NMF). Firstly, mathematic models of microphone array and room impulse response are built. In addition, we extracted blindly initialization parameters of 2-D convolutional NMF using k-means clustering algorithm and singular value decomposition algorithm, which can be used to accurately estimate the main components of desired sound source in the reverberation environment of multi-path propagation. Moreover, the feedback mechanism is introduced into deep 2-D convolutional NMF and correlation coefficient between the signal decomposed by NMF and the signal to be decomposed is used to select the best separated signal for DOA estimation, which make the separation algorithm simpler and more efficient. Finally, test of orthogonality of projected subspaces (TOPS) algorithm is used to validate the DOA estimation capability of this algorithm. Compared with the unprocessed reverberation speech, the estimation error is reduced, which shows that the proposed algorithm can effectively improve the estimation accuracy of DOA estimation when the received signals are in a reverberant environment.
TL;DR: This is the first of two papers aimed at establishing a dynamically grounded hierarchy comprising Clausius, Boltzmann, Gibbs, Shannon, metric and topological entropy in which each element is ideally a special case of its successor or some kind of limit thereof.
Abstract: A rigorous dynamical systems-based hierarchy is established for the definitions of entropy of Shannon (information), Kolmogorov–Sinai (metric) and Adler, Konheim & McAndrew (topological). In particular, metric entropy, with the imposition of some additional properties, is proven to be a special case of topological entropy and Shannon entropy is shown to be a particular form of metric entropy. This is the first of two papers aimed at establishing a dynamically grounded hierarchy comprising Clausius, Boltzmann, Gibbs, Shannon, metric and topological entropy in which each element is ideally a special case of its successor or some kind of limit thereof.
TL;DR: In this paper, the authors used replicated copper and bone awls in a controlled punching experiment that utilized an Instron Universal Materials Tester, and demonstrated that copper awls require significantly less force to punch through leather relative to bone tools, which strongly support the hypothesis that tool function played an important role in the evolution of the North American copper tool repertoire.
Heidelberg University1, Institut d'Astrophysique de Paris2, Goddard Space Flight Center3, Las Cumbres Observatory Global Telescope Network4, University of Warsaw5, Istituto Nazionale di Fisica Nucleare6, New York University Abu Dhabi7, University of St Andrews8, University of Manchester9, University of Edinburgh10, Liverpool John Moores University11, International Space Science Institute12, Ohio State University13, University of Copenhagen14, Max Planck Society15, Keele University16, University of Antofagasta17, Korea Astronomy and Space Science Institute18, University of Hamburg19, Aarhus University20, Sharif University of Technology21, Chinese Academy of Sciences22, University of Liège23, Pontifical Catholic University of Chile24, California Institute of Technology25, University of Salerno26, University of Rome Tor Vergata27, Nagoya University28, University of Maryland, College Park29, University of Auckland30, Osaka University31, Massey University32, Vaughn College of Aeronautics and Technology33, Victoria University, Australia34, University of Canterbury35, Kyoto Sangyo University36
TL;DR: In this article, the authors present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes, and find that the event was most likely caused by a stellar binary-lens with masses M{\star 1} = 0.87 ± 0.12 M{⊙} and M_{\star 2} =
Abstract: We present the analysis of stellar binary microlensing event OGLE-2015-BLG-0060 based on observations obtained from 13 different telescopes. Intensive coverage of the anomalous parts of the light curve was achieved by automated follow-up observations from the robotic telescopes of the Las Cumbres Observatory. We show that, for the first time, all main features of an anomalous microlensing event are well covered by follow-up data, allowing us to estimate the physical parameters of the lens. The strong detection of second-order effects in the event light curve necessitates the inclusion of longer-baseline survey data in order to constrain the parallax vector. We find that the event was most likely caused by a stellar binary-lens with masses M_{\star 1} = 0.87 ± 0.12 M_{⊙} and M_{\star 2} = 0.77 ± 0.11 M_{⊙}. The distance to the lensing system is 6.41 ± 0.14 kpc and the projected separation between the two components is 13.85 ± 0.16 au. Alternative interpretations are also considered.
01 Jun 2019
TL;DR: Human testing of the novel assistive device indicated that the SW-SiStA was able to provide effective sit-to-stand assistance in a natural way, and the users were able to expend significantly less muscle efforts in the process.
Abstract: With the aging of the population in the United States, an increasing number of individuals suffer from mobility challenges. For such individuals, the difficulty of standing up from a seated position is a major barrier for their daily physical activities. In the paper, a novel assistive device, namely Semi-Wearable Sit-to-Stand Assist (SW-SiStA), is presented, which provides effective lower-limb assistance to overcome such difficulty for the mobility-challenged individuals. Unlike traditional exoskeletons, the SW-SiStA can be easily detached after the completion of the sit-to-stand process, and thus will not cause additional burden to the user during the subsequent ambulation. The SW-SiStA is powered with a pneumatic actuator, leverage its advantages of low cost and high power/force density. The complexity of the device is reduced by the use of a simple solenoid valve in combination with two adjustable needle valves, providing the desired individualized adjustability without the expensive proportional valves. Human testing of the device indicated that the SW-SiStA was able to provide effective sit-to-stand assistance in a natural way, and the users were able to expend significantly less muscle efforts in the process.
TL;DR: In this paper, a new scheme is proposed and demonstrated by using a polarization-maintaining bidirectional coupled optoelectronic oscillator (COEO) incorporating a Sagnac loop structure.
01 Oct 2019
TL;DR: Results show that this adaptive EMD-TNMF algorithm can estimate the source number and convolution order correctly and obtain better separated source signals.
Abstract: Single channel blind source separation (SCBSS) using time-frequency nonnegative matrix factorization (NMF) has some shortcomings, where the source number and convolution order must be known and it's sensitive to the factors (e.g. window function, window length and overlap ratio of adjacent windows). To compensate these shortcomings that cannot meet the real application, we proposed an adaptive EMD-TNMF algorithm, which can estimate both the source number and the convolution order and is applicable to both single channel linear instantaneous and convolutive mixtures. Firstly, the single channel signal is mapped into multiple channels by utilizing empirical mode decomposition (EMD), and the number of independent sources is estimated by applying eigenvalue descent ratio of the IMFs' covariance matrix. Secondly, the autocorrelation-based method is used to estimate the convolution order. Thirdly, the nonnegative matrix is constructed by adding one positive matrix (all elements are positive). Finally, in time domain, NMF algorithm is used to separate source signals. The algorithm's performance is verified by two experiments where the single channel signal is linear instantaneous mixing of four artificial signals and linear convolutive mixing of two speech signals respectively. Results show that this algorithm can estimate the source number and convolution order correctly and obtain better separated source signals.
01 Jun 2019
TL;DR: Results showed that quadruped robotic platform can maintain a statically stability which demonstrate the feasibility and capability of the robotic application for walking assistance.
Abstract: Mobility impairment is becoming a challenging issue around the world with a rapid increase on aging population. Existing tools of walking assistance for mobility-impaired people include passive canes or wheeled rollators which increase energy consumption on the users and disturb the users’ walking rhythm, and powered wheeled chairs which could preclude the muscle activities and accelerate the degeneration of the lower limbs. The research in this paper aiming at helping mobility-impaired people proposes a novel robotic platform with quadrupedal locomotion. With motorized actuation, the quadruped robotic platform could accompany the user at the center and provide protection and possible walking assistance if needed. As the robotic platform is equipped with a leg locomotion, it can enlarge the user’s activity environments, such as both indoor flat floor and outdoor uneven terrain. It can even assist the user to involve in some mobility challenging activities, such as climbing stairs. In this paper, we illustrate the mechanical design of the robotic platform. A continuous gait planning is proposed to create a smooth locomotion for the robot. To quantify the performance, a system-level walking experimentation was conducted, and the results showed that quadruped robotic platform can maintain a statically stability which demonstrate the feasibility and capability of the robotic application for walking assistance.
TL;DR: In this article, an analisis del nivel de contaminación produced by the gases generated by monoxido de carbono (CO), dioxido of carbono(CO2), and the hidrocarburos (HC) in the limpieza de metalicas de acero inoxidable AISI/SAE 304 is presented.
Abstract: La presente investigacion aborda un analisis del nivel de contaminacion producido por los gases generados de monoxido de carbono (CO), dioxido de carbono (CO2) y los hidrocarburos (HC) en la limpieza de laminas metalicas de acero inoxidable AISI/SAE 304 aplicando plasma frio de oxigeno a baja presion para la remocion de los aceites ISO 32, ISO 68 e ISO 220, con diferentes parametros de control del generador de acuerdo con el aceite lubricante removido de la superficie de la lamina metalica de acero inoxidable. La experimentacion se realizo en un primer proceso con una descarga aplicada directamente a la superficie de la lamina impregnada con el aceite colocando con un volumen de 0,1 ml y en un segundo proceso donde la lamina con el aceite impregnado fue sumergida en un desengrasante para aceites y grasas con la finalidad de realizar una limpieza previa a la aplicacion del plasma frio a baja presion en la superficie. Para el analisis de los resultados en el nivel de gases generados por cada aceite se aplica un analisis estadistico para determinar si existe una diferencia significativa en el nivel de los gases generados en las dos etapas.
01 Oct 2019
TL;DR: The results show that the fault diagnosis implementation proposed in this paper has high real-time performance, low resource consumption and low power consumption, which can provide an important reference for complex equipment PHM engineering applications.
Abstract: Aiming at the problems of poor real-time fault diagnosis and low efficiency in the complex equipment PHM engineering maturity, a fault diagnosis implementation scheme based on PHM high performance computing platform is proposed. The BP neural network algorithm is used as an example to verify. Firstly, the current technical status and urgent needs of the existing PHM operation platform are analyzed. The overall structure and software and hardware optimization configuration of PHM high performance computing platform with FPGA and DSP as the core are expounded. Then, by means of module division, HDL design, functional verification and package testing of the time domain feature extraction method and BP neural network, the implementation of the platform fault diagnosis algorithm is carried out. Finally, combined with the analysis of a certain type of on-board fuel pump fault data, comparative analysis was carried out with the CPU platform operation. The results show that the fault diagnosis implementation proposed in this paper has high real-time performance, low resource consumption and low power consumption, which can provide an important reference for complex equipment PHM engineering applications.
04 Jun 2019
TL;DR: In this paper, the remaining useful life of an airborne fuel pump was predicted based on condition-based maintenance under the technology framework of prognostic and health management, which is the core of condition prediction.
Abstract: Remaining useful life prediction is the core of condition-based maintenance under the technology framework of prognostic and health management. But the remaining useful life of airborne fuel pump a...
01 Feb 2019
TL;DR: A new robust high-degree Cubature Kalman filtering algorithm is proposed, which takes into account the nonlinearity of the system and non-gaussian noise, and improves the measurement updating process by using the Maximum correntropy criterion and converts the traditional measurement updating problem into the linear regressione quation solving problem.
Abstract: As the integrated navigation system is a nonlinear system, in the case of non-gaussian noise, the traditional nonlinear gaussian filtering algorithm has a serious problem of decreasing filtering precision. In this paper, a new robust high-degree Cubature Kalman filtering algorithm is proposed, which takes into account the nonlinearity of the system and non-gaussian noise. The algorithm improves the measurement updating process by using the Maximum correntropy criterion(MCC), and converts the traditional measurement updating problem into the linear regressione quation solving problem. Combines the advantages of Maximum correntropy criterion and Cubature Kalman filter to deal with non-Gaussian and nonlinear systems. The proposed algorithm is applied to the SINS/GPS integrated navigation system, the simulation results show that the proposed algorithm's filtering performance is greatly affected by the kernel width. Under the condition of gaussian mixture noise, the new robust high-degree Cubature Kalman filter based on Maximum correntropy criterion(MCC-HCKF) is more robust and has higher filtering precision than the traditional high-degree Cubature Kalman filter(HCKF).
TL;DR: This paper first proves the existence of fuzzy prekernels and fuzzy nucleolus in TU fuzzy games which generalize the corresponding results for classical TU games and provides an axiomatization theorem for fuzzy preKernels.
01 Nov 2019
TL;DR: An optimization method based on Bessel curve's minimum and high-order displacement derivative trajectory is proposed, which solves the problem of energy loss during flight.
Abstract: Aiming at the problem that there could be a lot of non-differentiable points in the displacement, velocity and acceleration functions of the trajectory generated in the path planning of Four-rotor UAV, an optimization method based on Bessel curve's minimum and high-order displacement derivative trajectory is proposed. Firstly, the trajectory is optimized by the method of minimum displacement derivative, which provides input for the Four-rotor position loop controller. Secondly, the Bessel curve is introduced to the optimization function. By discussing the flight constraints of the Four-rotor UAV, the trajectory is transformed into a convex quadratic programming problem and solved by the interior point method. Finally, the trajectory is created by using the fast marching algorithm to optimize the simulation before and after. The simulation results show that the optimized trajectory is continuous and differentiable, which solves the problem of energy loss during flight.