Pub Date : 2024-10-21DOI: 10.1016/j.ast.2024.109683
Carlos Montañez-Molina , Javier Pliego-Jiménez
Multirotor aerial vehicles are versatile flying robots that perform hovering, vertical take-off and landing, and aggressive maneuvers in a 3D environment. Due to their underactuated nature, the aerial vehicles' position and orientation cannot be controlled independently. For this reason, most of the quadrotors' tasks involved position tracking or regulation tasks. This paper focuses on the position-tracking problem of quadrotors using the reduced orientation of the vehicle, meaning that only two degrees of freedom of the robot's orientation are controlled. We propose an almost global exponential reduced attitude control law that aligns the aerial robot's thrust direction with the desired force that drives the robot along the desired position trajectory. For the translational subsystem, we propose a dynamic control law that drives the position and velocity of the quadrotors asymptotically to the desired trajectories. The proposed attitude control law is computationally simple, and thus, it is suitable to run on board. Finally, we provide experimental results performed on a low-cost quadrotor and a comparison study with a full-attitude controller to illustrate the performance and advantages of the proposed control laws.
{"title":"Position and reduced attitude trajectory tracking control of quadrotors: Theory and experiments","authors":"Carlos Montañez-Molina , Javier Pliego-Jiménez","doi":"10.1016/j.ast.2024.109683","DOIUrl":"10.1016/j.ast.2024.109683","url":null,"abstract":"<div><div>Multirotor aerial vehicles are versatile flying robots that perform hovering, vertical take-off and landing, and aggressive maneuvers in a 3D environment. Due to their underactuated nature, the aerial vehicles' position and orientation cannot be controlled independently. For this reason, most of the quadrotors' tasks involved position tracking or regulation tasks. This paper focuses on the position-tracking problem of quadrotors using the reduced orientation of the vehicle, meaning that only two degrees of freedom of the robot's orientation are controlled. We propose an almost global exponential reduced attitude control law that aligns the aerial robot's thrust direction with the desired force that drives the robot along the desired position trajectory. For the translational subsystem, we propose a dynamic control law that drives the position and velocity of the quadrotors asymptotically to the desired trajectories. The proposed attitude control law is computationally simple, and thus, it is suitable to run on board. Finally, we provide experimental results performed on a low-cost quadrotor and a comparison study with a full-attitude controller to illustrate the performance and advantages of the proposed control laws.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109683"},"PeriodicalIF":5.0,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.ast.2024.109676
Salman Ijaz , Yuhao Shi , Yasir Ali Khan , Maria Khodaverdian , Umair Javaid
In precision agriculture, such as crop spraying, controlling UAVs presents various challenges such as variable payload, inertial coefficient variation, influence of external disturbances such as wind gusts, and uncertainties associated with the dynamics. To address these challenges, this paper proposes a hybrid control technique that combines higher-order integral sliding mode control, fast-terminal sliding mode control, and adaptive law. The objective is to mitigate the effects of variable payload, external disturbances, and uncertainties while maintaining the stability and performance of the UAV during spraying. Initially, a mathematical model is constructed for a coaxial octocopter UAV that is fitted with a spraying tank. This model takes into account the variation in mass and moment of inertia. Then, a two-loop control structure is employed to attain control of both the translational and rotational axis of the UAV. The numerical simulations are performed on a nonlinear model of the agricultural UAV system and compared with neural network based sliding mode control and robust adaptive backstepping control schemes. The robustness of the proposed scheme is tested in wind gusts and sensor measurement error conditions. Finally, hardware-in-loop simulations are performed using the Pixhawk Orange Cube flight controller to validate the real-time capability of the proposed scheme.
{"title":"Robust adaptive control law design for enhanced stability of agriculture UAV used for pesticide spraying","authors":"Salman Ijaz , Yuhao Shi , Yasir Ali Khan , Maria Khodaverdian , Umair Javaid","doi":"10.1016/j.ast.2024.109676","DOIUrl":"10.1016/j.ast.2024.109676","url":null,"abstract":"<div><div>In precision agriculture, such as crop spraying, controlling UAVs presents various challenges such as variable payload, inertial coefficient variation, influence of external disturbances such as wind gusts, and uncertainties associated with the dynamics. To address these challenges, this paper proposes a hybrid control technique that combines higher-order integral sliding mode control, fast-terminal sliding mode control, and adaptive law. The objective is to mitigate the effects of variable payload, external disturbances, and uncertainties while maintaining the stability and performance of the UAV during spraying. Initially, a mathematical model is constructed for a coaxial octocopter UAV that is fitted with a spraying tank. This model takes into account the variation in mass and moment of inertia. Then, a two-loop control structure is employed to attain control of both the translational and rotational axis of the UAV. The numerical simulations are performed on a nonlinear model of the agricultural UAV system and compared with neural network based sliding mode control and robust adaptive backstepping control schemes. The robustness of the proposed scheme is tested in wind gusts and sensor measurement error conditions. Finally, hardware-in-loop simulations are performed using the Pixhawk Orange Cube flight controller to validate the real-time capability of the proposed scheme.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109676"},"PeriodicalIF":5.0,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.ast.2024.109679
Yanpi Lin , Lei Wang , Fang Zhang , Xiaojun Li , Zuchao Zhu
The harsh and complex working environment such as low temperature, high pressure and high speed in the turbopump brings great challenges to the working performance, operation stability and structural safety of the turbine pump device. In this research, the cryogenic cavitation of methane pump in liquid oxygen-methane rocket engine is studied by the combination of experiment and high-performance computing cluster numerical simulation. The unsteady flow calculation of the methane pump is carried out to reveal the cavitation and its temperature-pressure correlated characteristics of the methane pump in different operation conditions. A cryogenic cavitation model considering the thermal effect of cryogenic medium is established and the cryogenic cavitation simulation of methane pump is carried out. The hydraulic and cavitation performance experiments of methane pump are also performed. It is demonstrated that: 1) The volume fraction and cycle of cavitation in pump will decrease exponentially with the increase of inlet pressure. The cavitation cycle under low inlet pressure (0.146 MPa) is five times of that under high inlet pressure (0.3 MPa). 2) The decrease of inlet pressure will lead to the decrease of Strouhal number, which will weaken the unsteady cavitation effect of methane pump and enhance the influence of fluid inertia effect on cavitation. 3) Cavitation in inducer is mainly dominated by the backflow vortex cavitation (BVC) and the blade cavitation (BC) under lower inlet pressure condition, while the backflow vortex cavitation (BVC) and the tip vortex (TVC) cavitation are the main contribution in higher inlet pressure conditions. Through the study of cryogenic cavitation under harsh pump working conditions is benefit to reveal the cavitation mechanism of methane pump, and provide theoretical basis and technical support for the improvement design of turbopump.
{"title":"Study on cryogenic cavitation and its temperature-pressure correlated characteristics of methane pump in rocket engine","authors":"Yanpi Lin , Lei Wang , Fang Zhang , Xiaojun Li , Zuchao Zhu","doi":"10.1016/j.ast.2024.109679","DOIUrl":"10.1016/j.ast.2024.109679","url":null,"abstract":"<div><div>The harsh and complex working environment such as low temperature, high pressure and high speed in the turbopump brings great challenges to the working performance, operation stability and structural safety of the turbine pump device. In this research, the cryogenic cavitation of methane pump in liquid oxygen-methane rocket engine is studied by the combination of experiment and high-performance computing cluster numerical simulation. The unsteady flow calculation of the methane pump is carried out to reveal the cavitation and its temperature-pressure correlated characteristics of the methane pump in different operation conditions. A cryogenic cavitation model considering the thermal effect of cryogenic medium is established and the cryogenic cavitation simulation of methane pump is carried out. The hydraulic and cavitation performance experiments of methane pump are also performed. It is demonstrated that: 1) The volume fraction and cycle of cavitation in pump will decrease exponentially with the increase of inlet pressure. The cavitation cycle under low inlet pressure (0.146 MPa) is five times of that under high inlet pressure (0.3 MPa). 2) The decrease of inlet pressure will lead to the decrease of Strouhal number, which will weaken the unsteady cavitation effect of methane pump and enhance the influence of fluid inertia effect on cavitation. 3) Cavitation in inducer is mainly dominated by the backflow vortex cavitation (BVC) and the blade cavitation (BC) under lower inlet pressure condition, while the backflow vortex cavitation (BVC) and the tip vortex (TVC) cavitation are the main contribution in higher inlet pressure conditions. Through the study of cryogenic cavitation under harsh pump working conditions is benefit to reveal the cavitation mechanism of methane pump, and provide theoretical basis and technical support for the improvement design of turbopump.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109679"},"PeriodicalIF":5.0,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.ast.2024.109677
Zhenwei Ma , Qiufeng Wang
This paper investigates the adaptive control problem for nonlinear time-varying systems with unknown parameters and model uncertainties. A novel class of switching functions is designed, and its construction method is detailed, along with a proof of the continuity of its order derivatives. Two simple examples are provided to illustrate how the proposed congelation of variables method handles unknown high-frequency time-varying parameters in both the feedback and input paths. A new neural network control scheme is then developed, integrating an adaptive neural network controller with a robust controller. The smooth transition between these two controllers is ensured by the novel switching function, which guarantees global system stability. Furthermore, by combining the congelation of variables method with adaptive backstepping, a new adaptive tracking control scheme is proposed. This scheme effectively handles unknown high-frequency time-varying parameters while achieving asymptotic tracking of arbitrary reference signals. Simulation results show that the proposed novel adaptive control method delivers superior control accuracy while reducing energy consumption: it achieves an order of magnitude improvement over the traditional adaptive robust control method and two orders of magnitude improvement over the conventional sliding mode control method.
{"title":"Adaptive control of nonlinear time-varying systems with unknown parameters and model uncertainties","authors":"Zhenwei Ma , Qiufeng Wang","doi":"10.1016/j.ast.2024.109677","DOIUrl":"10.1016/j.ast.2024.109677","url":null,"abstract":"<div><div>This paper investigates the adaptive control problem for nonlinear time-varying systems with unknown parameters and model uncertainties. A novel class of switching functions is designed, and its construction method is detailed, along with a proof of the continuity of its <span><math><mi>n</mi><mo>−</mo><mn>1</mn></math></span> order derivatives. Two simple examples are provided to illustrate how the proposed congelation of variables method handles unknown high-frequency time-varying parameters in both the feedback and input paths. A new neural network control scheme is then developed, integrating an adaptive neural network controller with a robust controller. The smooth transition between these two controllers is ensured by the novel switching function, which guarantees global system stability. Furthermore, by combining the congelation of variables method with adaptive backstepping, a new adaptive tracking control scheme is proposed. This scheme effectively handles unknown high-frequency time-varying parameters while achieving asymptotic tracking of arbitrary reference signals. Simulation results show that the proposed novel adaptive control method delivers superior control accuracy while reducing energy consumption: it achieves an order of magnitude improvement over the traditional adaptive robust control method and two orders of magnitude improvement over the conventional sliding mode control method.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109677"},"PeriodicalIF":5.0,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-20DOI: 10.1016/j.ast.2024.109684
I.P. Wall, M.R. Amoozgar, A.A. Popov
In this paper, the effectiveness of nonlinear energy sinks on enhancing aeroelastic stability and post-instability response of aircraft wings is investigated. The wing has two degrees of freedom in bending and torsion, and is modelled using an extended Euler-Bernoulli beam theory with hardening nonlinearity. A Nonlinear Energy Sink (NES) absorber is embedded inside the wing distributed along the wing span. The wing attached unsteady aerodynamic loads are simulated using the Wagner's indicial lift model. The structural dynamics of the wing are derived using Extended Hamilton's Principle and it is discretised using Galerkin's method. The NES mass is connected to the wing spar through a linear damper and nonlinear spring with a cubic stiffness nonlinearity. The coupled aeroelastic equations are then transformed to state space. Then, integrated numerically to resolve the bending and torsional response of the wing to study the impact of spanwise and chordwise positions of the embedded NES on flutter suppression and instability response enhancement. The results demonstrate that the NES is most efficient and is most sensitive to changes in the stiffness when placed at the wingtip. For a given chordwise location, it is found that there is a range of flow speeds over which the NES is most effective and reducing the chordwise offset lowers the speed of the peak efficiency range and moves it closer to the flutter speed. In addition, increasing the stiffness coefficient of the NES improves the efficiency of the device in the immediate post-flutter region. Two near optimum NES devices are proposed with a mass ratios of 1% (located at the wingtip) and 2.5% (located at 75% span). Both of these improve the flutter speed by 5%, and reduce the post-flutter response by 64.5% and 59.2%, respectively.
本文研究了非线性能量汇对增强飞机机翼气动弹性稳定性和失稳后响应的有效性。机翼在弯曲和扭转时有两个自由度，并使用带有硬化非线性的扩展欧拉-伯努利梁理论进行建模。机翼内部嵌入了一个沿翼展分布的非线性能量吸收器（NES）。利用瓦格纳指示升力模型模拟了机翼附着的非稳定气动载荷。机翼的结构动力学是利用扩展汉密尔顿原理推导出来的，并采用伽勒金方法对其进行离散化处理。NES 质量通过线性阻尼器和具有立方刚度非线性的非线性弹簧与翼展相连。然后将耦合气动弹性方程转换到状态空间。然后，通过数值积分解析机翼的弯曲和扭转响应，研究嵌入式 NES 的跨度和弦向位置对抑制扑翼和增强失稳响应的影响。结果表明，当 NES 位于翼尖时，其效率最高，对刚度的变化最为敏感。对于给定的弦向位置，发现 NES 最有效的流速范围是存在的，而减少弦向偏移会降低峰值效率范围的速度，并使其更接近扑翼速度。此外，增大 NES 的刚度系数还能提高设备在紧接扑翼后区域的效率。我们提出了两个接近最佳的 NES 装置，其质量比分别为 1%（位于翼尖）和 2.5%（位于 75% 跨度）。这两种装置都将扑翼速度提高了 5%，并将扑翼后响应分别降低了 64.5% 和 59.2%。
{"title":"Aeroelasticity of an aircraft wing with nonlinear energy sink","authors":"I.P. Wall, M.R. Amoozgar, A.A. Popov","doi":"10.1016/j.ast.2024.109684","DOIUrl":"10.1016/j.ast.2024.109684","url":null,"abstract":"<div><div>In this paper, the effectiveness of nonlinear energy sinks on enhancing aeroelastic stability and post-instability response of aircraft wings is investigated. The wing has two degrees of freedom in bending and torsion, and is modelled using an extended Euler-Bernoulli beam theory with hardening nonlinearity. A Nonlinear Energy Sink (NES) absorber is embedded inside the wing distributed along the wing span. The wing attached unsteady aerodynamic loads are simulated using the Wagner's indicial lift model. The structural dynamics of the wing are derived using Extended Hamilton's Principle and it is discretised using Galerkin's method. The NES mass is connected to the wing spar through a linear damper and nonlinear spring with a cubic stiffness nonlinearity. The coupled aeroelastic equations are then transformed to state space. Then, integrated numerically to resolve the bending and torsional response of the wing to study the impact of spanwise and chordwise positions of the embedded NES on flutter suppression and instability response enhancement. The results demonstrate that the NES is most efficient and is most sensitive to changes in the stiffness when placed at the wingtip. For a given chordwise location, it is found that there is a range of flow speeds over which the NES is most effective and reducing the chordwise offset lowers the speed of the peak efficiency range and moves it closer to the flutter speed. In addition, increasing the stiffness coefficient of the NES improves the efficiency of the device in the immediate post-flutter region. Two near optimum NES devices are proposed with a mass ratios of 1% (located at the wingtip) and 2.5% (located at 75% span). Both of these improve the flutter speed by 5%, and reduce the post-flutter response by 64.5% and 59.2%, respectively.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109684"},"PeriodicalIF":5.0,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.ast.2024.109663
Ze Wang , Weiwei Zhang , Xu Wang , Shufang Song
Data-driven modeling methods have become one of the main technologies for predicting aerodynamic heat in hypersonic conditions. However, due to the limitations of wind tunnel experimental conditions, the spatial distribution of aerothermal wind tunnel experimental data is often sparse, and the sample size is relatively small. Furthermore, there is a lack of direct correlation in the aerodynamic heat distribution data among different shapes of vehicles, which poses challenges for constructing high-performance data-driven aerodynamic heat prediction models. To address these issues, this paper proposes a high-precision aerodynamic heat modeling and prediction method based on data augmentation and transfer learning. First, integrating the concept of data fusion, we propose to enhance the sparse aerothermal wind tunnel experimental data by using deep neural networks and introducing low-precision numerical computation results. Next, based on the close physical correlation between boundary layer outer edge information and wall surface aerodynamic heat, we construct the aerodynamic heat prediction model ED-ResNet using a double-series residual neural network. Finally, by fine-tuning the ED-ResNet model for transfer learning, high-precision predictions of aerothermal wind tunnel experimental results for different shaped vehicles are achieved under small sample conditions. Verification using hypersonic double-ellipsoid, blunt cone, and blunt bicone shows that after data augmentation, the prediction error of the aerodynamic heat prediction model is significantly reduced to 1/3 of that when data augmentation is not used. Moreover, through transfer learning, the model effectively leverages existing hypersonic double-ellipsoid aerothermal wind tunnel experimental data to achieve high-precision predictions of aerodynamic heat distribution for blunt cone and blunt double cone under different incoming flow conditions, with normalized root mean square error(NRMSE) maintained below 10 %.
{"title":"High precision aerodynamic heat prediction method based on data augmentation and transfer learning","authors":"Ze Wang , Weiwei Zhang , Xu Wang , Shufang Song","doi":"10.1016/j.ast.2024.109663","DOIUrl":"10.1016/j.ast.2024.109663","url":null,"abstract":"<div><div>Data-driven modeling methods have become one of the main technologies for predicting aerodynamic heat in hypersonic conditions. However, due to the limitations of wind tunnel experimental conditions, the spatial distribution of aerothermal wind tunnel experimental data is often sparse, and the sample size is relatively small. Furthermore, there is a lack of direct correlation in the aerodynamic heat distribution data among different shapes of vehicles, which poses challenges for constructing high-performance data-driven aerodynamic heat prediction models. To address these issues, this paper proposes a high-precision aerodynamic heat modeling and prediction method based on data augmentation and transfer learning. First, integrating the concept of data fusion, we propose to enhance the sparse aerothermal wind tunnel experimental data by using deep neural networks and introducing low-precision numerical computation results. Next, based on the close physical correlation between boundary layer outer edge information and wall surface aerodynamic heat, we construct the aerodynamic heat prediction model ED-ResNet using a double-series residual neural network. Finally, by fine-tuning the ED-ResNet model for transfer learning, high-precision predictions of aerothermal wind tunnel experimental results for different shaped vehicles are achieved under small sample conditions. Verification using hypersonic double-ellipsoid, blunt cone, and blunt bicone shows that after data augmentation, the prediction error of the aerodynamic heat prediction model is significantly reduced to 1/3 of that when data augmentation is not used. Moreover, through transfer learning, the model effectively leverages existing hypersonic double-ellipsoid aerothermal wind tunnel experimental data to achieve high-precision predictions of aerodynamic heat distribution for blunt cone and blunt double cone under different incoming flow conditions, with normalized root mean square error(NRMSE) maintained below 10 %.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109663"},"PeriodicalIF":5.0,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.ast.2024.109670
Hanwen Guo , Donghai Jin , Jiancheng Zhang , Hao Yu , Yucheng Dai
Profiled end wall provides a novel and effective solution for end wall flow control in turbines and compressors. However, the application of profiled end walls in compressors still lacks quantitative design rules. This paper presents a quantitative design rule for end wall profiling based on a three-dimensional inverse method and numerically validates it on a highly loaded compressor cascade. The current inverse method can solve the corresponding end wall shape from a given end wall pressure distribution, but the determination of the end wall pressure distribution heavily relies on empirical knowledge. This study establishes a model between streamline curvature and cross-passage pressure gradient (CPG) through the circumferential equilibrium equation in the S1 stream surface, thereby providing a quantitative basis for determining the end wall pressure distribution. The quantitative design rule proposed in this paper is expressed as follows: at the axial position where the separation begins on the suction surface (SS), within the range of 0.1–0.2 pitch away from the SS, the end wall boundary layer fluid with a higher velocity than the corner region average velocity should possess the same streamline curvature as the fluid within the viscous sublayer. The inverse-designed profiled end wall using the quantitative design rule enhances the local cross-flow near the SS by imposing a stronger CPG, thus encouraging the end wall boundary layer fluid with relatively higher momentum to arrive at the SS earlier and enhancing the radial migration on the SS. Consequently, the intensified cross-flow entrains relatively higher momentum into the corner region, while the enhanced radial migration drives the low-momentum fluid away from the corner region towards the midspan. Finally, the inverse-designed profiled end wall reduces the half-span mass-flow-weighted average loss by 4.3%.
异型端壁为涡轮机和压缩机的端壁流量控制提供了一种新颖而有效的解决方案。然而，在压缩机中应用异型端壁仍缺乏定量设计规则。本文提出了一种基于三维逆方法的端壁仿形定量设计规则，并在高负荷压缩机级联上进行了数值验证。目前的反演方法可以根据给定的端壁压力分布求解相应的端壁形状，但端壁压力分布的确定在很大程度上依赖于经验知识。本研究通过 S1 流面的圆周平衡方程，建立了流线曲率与跨通道压力梯度（CPG）之间的模型，从而为确定端壁压力分布提供了定量依据。本文提出的定量设计规则表述如下：在吸力面（SS）上分离开始的轴向位置，距离 SS 0.1-0.2 节距范围内，速度高于转角区域平均速度的端壁边界层流体应与粘性子层内的流体具有相同的流线曲率。采用定量设计规则的反设计异型端壁通过施加更强的 CPG 来增强 SS 附近的局部交叉流，从而促使具有相对较大动量的端壁边界层流体更早到达 SS，并增强 SS 上的径向迁移。因此，加强的交叉流将相对较高的动量夹带到转角区域，而加强的径向迁移则将低动量流体从转角区域驱向中跨。最后，反向设计的异型端壁将半跨质量流加权平均损失降低了 4.3%。
{"title":"A quantitative three-dimensional inverse design rule based on cross-flow control of profiled end wall","authors":"Hanwen Guo , Donghai Jin , Jiancheng Zhang , Hao Yu , Yucheng Dai","doi":"10.1016/j.ast.2024.109670","DOIUrl":"10.1016/j.ast.2024.109670","url":null,"abstract":"<div><div>Profiled end wall provides a novel and effective solution for end wall flow control in turbines and compressors. However, the application of profiled end walls in compressors still lacks quantitative design rules. This paper presents a quantitative design rule for end wall profiling based on a three-dimensional inverse method and numerically validates it on a highly loaded compressor cascade. The current inverse method can solve the corresponding end wall shape from a given end wall pressure distribution, but the determination of the end wall pressure distribution heavily relies on empirical knowledge. This study establishes a model between streamline curvature and cross-passage pressure gradient (CPG) through the circumferential equilibrium equation in the S1 stream surface, thereby providing a quantitative basis for determining the end wall pressure distribution. The quantitative design rule proposed in this paper is expressed as follows: at the axial position where the separation begins on the suction surface (SS), within the range of 0.1–0.2 pitch away from the SS, the end wall boundary layer fluid with a higher velocity than the corner region average velocity should possess the same streamline curvature as the fluid within the viscous sublayer. The inverse-designed profiled end wall using the quantitative design rule enhances the local cross-flow near the SS by imposing a stronger CPG, thus encouraging the end wall boundary layer fluid with relatively higher momentum to arrive at the SS earlier and enhancing the radial migration on the SS. Consequently, the intensified cross-flow entrains relatively higher momentum into the corner region, while the enhanced radial migration drives the low-momentum fluid away from the corner region towards the midspan. Finally, the inverse-designed profiled end wall reduces the half-span mass-flow-weighted average loss by 4.3%.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109670"},"PeriodicalIF":5.0,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.ast.2024.109657
Prajakta Surve, Arnab Maity, Shashi Ranjan Kumar
This paper proposes a three-dimensional impact angle-constrained nonlinear guidance strategy against different types of targets. To avoid the occurrence of singularities, in Euler angle-based approaches, the development of this guidance strategy is solely based on quaternion dynamics. An explicit relationship between the quaternions representing impact orientation and line-of-sight orientation at the time of collision is derived. Based on the obtained relation, a guidance law is derived using a sliding mode control technique to track the desired line-of-sight orientation for target interception. The performance of the proposed guidance strategy is evaluated for constant-speed and different time-varying-speed interceptor models accounting for the effect of varying aerodynamic parameters on interceptor speed. The numerical simulations performed show satisfactory results for all engagements, validating the efficacy and robustness of the proposed guidance law.
{"title":"Quaternion-based non-singular nonlinear impact angle guidance for three-dimensional engagements","authors":"Prajakta Surve, Arnab Maity, Shashi Ranjan Kumar","doi":"10.1016/j.ast.2024.109657","DOIUrl":"10.1016/j.ast.2024.109657","url":null,"abstract":"<div><div>This paper proposes a three-dimensional impact angle-constrained nonlinear guidance strategy against different types of targets. To avoid the occurrence of singularities, in Euler angle-based approaches, the development of this guidance strategy is solely based on quaternion dynamics. An explicit relationship between the quaternions representing impact orientation and line-of-sight orientation at the time of collision is derived. Based on the obtained relation, a guidance law is derived using a sliding mode control technique to track the desired line-of-sight orientation for target interception. The performance of the proposed guidance strategy is evaluated for constant-speed and different time-varying-speed interceptor models accounting for the effect of varying aerodynamic parameters on interceptor speed. The numerical simulations performed show satisfactory results for all engagements, validating the efficacy and robustness of the proposed guidance law.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109657"},"PeriodicalIF":5.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.ast.2024.109674
Tsung-Ming Huang , Yueh-Cheng Kuo , Wen-Wei Lin , Chin-Tien Wu
The proposed strategy, finite-time state-dependent Riccati equation (FT-SDRE)-based impact angle guidance, is generally employed to solve the 3D pursuer/target interception model with fixed lateral accelerations. This article expands its application to a general scenario where the lateral acceleration of a target may change. To achieve this, we approximate the accelerations of the azimuth and elevation angles of the target in the inertial frame via second-order finite difference schemes and develop a high-performance FT-SDRE algorithm with structure-preserving doubling algorithms (SDAs). As a result, the update frequency of the controller can be increased, and better guidance of the pursuer can be obtained to address the high maneuverability of the target during the entire interception procedure. At every state of the FT-SDRE, a modified Newton–Lyapunov method is employed to solve the continuous algebraic Riccati equation (CARE), and a new simplified SDA with adaptive optimal parameter selection is proposed for solving the associated Lyapunov equation. Our numerical results demonstrate that the FT-SDRE algorithm accelerated by our proposed methods is approximately three times faster than the FT-SDRE algorithm, in which the MATLAB functions icare and lyap are used to solve the CARE and the Lyapunov equation, respectively, throughout the entire interception procedure. In other words, the control frequency can be increased threefold. In our benchmark cases where the target maneuvers with nonlinear lateral acceleration, the target can be intercepted earlier via the proposed FT-SDRE algorithm.
{"title":"An optimal parameterized Newton-type structure-preserving doubling algorithm for impact angle guidance-based 3D pursuer/target interception engagement","authors":"Tsung-Ming Huang , Yueh-Cheng Kuo , Wen-Wei Lin , Chin-Tien Wu","doi":"10.1016/j.ast.2024.109674","DOIUrl":"10.1016/j.ast.2024.109674","url":null,"abstract":"<div><div>The proposed strategy, finite-time state-dependent Riccati equation (FT-SDRE)-based impact angle guidance, is generally employed to solve the 3D pursuer/target interception model with fixed lateral accelerations. This article expands its application to a general scenario where the lateral acceleration of a target may change. To achieve this, we approximate the accelerations of the azimuth and elevation angles of the target in the inertial frame via second-order finite difference schemes and develop a high-performance FT-SDRE algorithm with structure-preserving doubling algorithms (SDAs). As a result, the update frequency of the controller can be increased, and better guidance of the pursuer can be obtained to address the high maneuverability of the target during the entire interception procedure. At every state of the FT-SDRE, a modified Newton–Lyapunov method is employed to solve the continuous algebraic Riccati equation (CARE), and a new simplified SDA with adaptive optimal parameter selection is proposed for solving the associated Lyapunov equation. Our numerical results demonstrate that the FT-SDRE algorithm accelerated by our proposed methods is approximately three times faster than the FT-SDRE algorithm, in which the MATLAB functions <strong>icare</strong> and <strong>lyap</strong> are used to solve the CARE and the Lyapunov equation, respectively, throughout the entire interception procedure. In other words, the control frequency can be increased threefold. In our benchmark cases where the target maneuvers with nonlinear lateral acceleration, the target can be intercepted earlier via the proposed FT-SDRE algorithm.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109674"},"PeriodicalIF":5.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.ast.2024.109681
Huifeng Miao , Zhibo Zhang , Xing Zheng , Lan Zhang , Yun Wu , Yinghong li
Ignition characteristics of the long electrode distance high-energy spark igniter (LHSI) in a cavity-stabilized scramjet combustor at low flight Mach has been numerically and experimentally investigated and compared with those of conventional lower energy spark igniter (SI). The effects of ignition and injection schemes on ignition performance were analyzed and the enhancement of greater spark energy were verified. The results show that the widest ignition boundary of SI is observed when the kerosene is injected in far field due to the sufficient evaporation of kerosene droplets and the disturbance caused by upstream cavity. Due to the greater energy deposition by LHSI, the ignition performance is markedly improved and the ignition boundary of combustor is extended from 0.131–0.148 to 0.091–0.224 under the scheme of I1+L2. The increased energy deposition of spark plasma ignites more combustible mixture and enhances the initial combustion, leading to a larger high-temperature zone. This is crucial for ensuring the survival of the flame kernel against dissipation of airflow in the scramjet combustor operating at low fight Mach numbers due to the short duration of spark discharge.
{"title":"Investigation on ignition enhancement characteristics by high-energy spark in a scramjet combustor under low flight Mach conditions","authors":"Huifeng Miao , Zhibo Zhang , Xing Zheng , Lan Zhang , Yun Wu , Yinghong li","doi":"10.1016/j.ast.2024.109681","DOIUrl":"10.1016/j.ast.2024.109681","url":null,"abstract":"<div><div>Ignition characteristics of the long electrode distance high-energy spark igniter (LHSI) in a cavity-stabilized scramjet combustor at low flight Mach has been numerically and experimentally investigated and compared with those of conventional lower energy spark igniter (SI). The effects of ignition and injection schemes on ignition performance were analyzed and the enhancement of greater spark energy were verified. The results show that the widest ignition boundary of SI is observed when the kerosene is injected in far field due to the sufficient evaporation of kerosene droplets and the disturbance caused by upstream cavity. Due to the greater energy deposition by LHSI, the ignition performance is markedly improved and the ignition boundary of combustor is extended from 0.131–0.148 to 0.091–0.224 under the scheme of I1+L2. The increased energy deposition of spark plasma ignites more combustible mixture and enhances the initial combustion, leading to a larger high-temperature zone. This is crucial for ensuring the survival of the flame kernel against dissipation of airflow in the scramjet combustor operating at low fight Mach numbers due to the short duration of spark discharge.</div></div>","PeriodicalId":50955,"journal":{"name":"Aerospace Science and Technology","volume":"155 ","pages":"Article 109681"},"PeriodicalIF":5.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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