Pub Date : 2023-08-31DOI: 10.3390/aerospace10090772
Shuce Wang, Minghua Hu, Zhening Chang, Xuhao Zhu
Air carriers shall not readily relinquish their held flight slots. In cases where the historical flight slot pool cannot be easily altered, a pressing need arises for an allocation method that can efficiently utilize the incremental resources of these time slots. This paper presents an integer planning model to address the efficient allocation of incremental airport time slot resources. The model considers the capacity of key resource nodes and flight waveforms as constraints to maximize the total incremental slots. Moreover, it considers the adaptation of strategic and tactical optimization. After conducting a case study using Beijing Capital International Airport for verification, the proposed model effectively reduces potential operational delays by 66.27% while adding 366 to 397-time slots. Notably, the model demonstrates remarkable delay reduction capabilities and can serve as a valuable decision-support tool for the incremental allocation of time slots.
{"title":"A Methodology for Allocating Incremental Resources in Single-Airport Time Slots","authors":"Shuce Wang, Minghua Hu, Zhening Chang, Xuhao Zhu","doi":"10.3390/aerospace10090772","DOIUrl":"https://doi.org/10.3390/aerospace10090772","url":null,"abstract":"Air carriers shall not readily relinquish their held flight slots. In cases where the historical flight slot pool cannot be easily altered, a pressing need arises for an allocation method that can efficiently utilize the incremental resources of these time slots. This paper presents an integer planning model to address the efficient allocation of incremental airport time slot resources. The model considers the capacity of key resource nodes and flight waveforms as constraints to maximize the total incremental slots. Moreover, it considers the adaptation of strategic and tactical optimization. After conducting a case study using Beijing Capital International Airport for verification, the proposed model effectively reduces potential operational delays by 66.27% while adding 366 to 397-time slots. Notably, the model demonstrates remarkable delay reduction capabilities and can serve as a valuable decision-support tool for the incremental allocation of time slots.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75645381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-31DOI: 10.3390/aerospace10090774
Kyung-Rae Koo, Hyun-Guk Kim, Dong-Geon Kim, Seong-Cheol Kwon, Hyun-Ung Oh
In the launch environment, satellites are subjected to severe dynamic loads. These dynamic loads in the launch environment can lead to the malfunction of the payload, or to mission failure. In order to improve the structural stability of satellites and enable the reliable execution of space missions, it is necessary to have a reinforcement structure that reduces structural vibrations. However, for active small SAR satellites, the mass requirements are very strict, and this makes it difficult to apply an additional structure for vibration reduction. Therefore, we have developed a carbon fiber-reinforced plastic (CFRP)-based laminated patch to obtain a vibration reduction structure with a lightweight design for improving the structural stability of an S-STEP satellite. To verify the vibration reduction performance of the CFRP-based patch, sine and random vibration tests were conducted at the specimen level. Finally, the structural stability of the S-STEP satellite with the proposed CFRP-based laminated patch was experimentally verified using sine and random vibration tests. The validation results indicate that the CFRP-based laminated patch is an efficient solution which can effectively reduce the vibration response without the need for major changes to the design of the satellite structure. The lightweight vibration reduction mechanism developed in this study is one of the best solutions for protecting vibration-sensitive components.
{"title":"Lightweight Design for Active Small SAR S-STEP Satellite Using Multilayered High-Damping Carbon Fiber-Reinforced Plastic Patch","authors":"Kyung-Rae Koo, Hyun-Guk Kim, Dong-Geon Kim, Seong-Cheol Kwon, Hyun-Ung Oh","doi":"10.3390/aerospace10090774","DOIUrl":"https://doi.org/10.3390/aerospace10090774","url":null,"abstract":"In the launch environment, satellites are subjected to severe dynamic loads. These dynamic loads in the launch environment can lead to the malfunction of the payload, or to mission failure. In order to improve the structural stability of satellites and enable the reliable execution of space missions, it is necessary to have a reinforcement structure that reduces structural vibrations. However, for active small SAR satellites, the mass requirements are very strict, and this makes it difficult to apply an additional structure for vibration reduction. Therefore, we have developed a carbon fiber-reinforced plastic (CFRP)-based laminated patch to obtain a vibration reduction structure with a lightweight design for improving the structural stability of an S-STEP satellite. To verify the vibration reduction performance of the CFRP-based patch, sine and random vibration tests were conducted at the specimen level. Finally, the structural stability of the S-STEP satellite with the proposed CFRP-based laminated patch was experimentally verified using sine and random vibration tests. The validation results indicate that the CFRP-based laminated patch is an efficient solution which can effectively reduce the vibration response without the need for major changes to the design of the satellite structure. The lightweight vibration reduction mechanism developed in this study is one of the best solutions for protecting vibration-sensitive components.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86251343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-31DOI: 10.3390/aerospace10090769
Bin Shen, Lingfei Xiao, Zhuolin Ye
In order to solve the problem of full flight envelope control for aircraft engines, the design of a linear parameter-varying (LPV) controller is described in this paper. First, according to the nonlinear aerodynamic model of the aircraft engine, the LPV engine model for the controller design is obtained through the Jacobian linearization and fitting technique. Then, the flight envelope is divided into several sub-regions, and the intersection of adjacent sub-regions is not empty. The sub-region LPV controller is designed using the parameter-dependent Lyapunov function (PDLF)-based LPV synthesis method, while eliminating the dependence of the LPV controller on scheduling parameter derivatives. In order to ensure the stability and performance of the aircraft engine across the full flight envelope, a mixing LPV control method is proposed to design the LPV controller in the overall region. The effectiveness of the proposed method is verified by simulating a dual-spool turbofan engine on a nonlinear component level model and comparing the proposed method with the gain scheduling based on PI and H∞ point design.
{"title":"A Full Envelope Robust Linear Parameter-Varying Control Method for Aircraft Engines","authors":"Bin Shen, Lingfei Xiao, Zhuolin Ye","doi":"10.3390/aerospace10090769","DOIUrl":"https://doi.org/10.3390/aerospace10090769","url":null,"abstract":"In order to solve the problem of full flight envelope control for aircraft engines, the design of a linear parameter-varying (LPV) controller is described in this paper. First, according to the nonlinear aerodynamic model of the aircraft engine, the LPV engine model for the controller design is obtained through the Jacobian linearization and fitting technique. Then, the flight envelope is divided into several sub-regions, and the intersection of adjacent sub-regions is not empty. The sub-region LPV controller is designed using the parameter-dependent Lyapunov function (PDLF)-based LPV synthesis method, while eliminating the dependence of the LPV controller on scheduling parameter derivatives. In order to ensure the stability and performance of the aircraft engine across the full flight envelope, a mixing LPV control method is proposed to design the LPV controller in the overall region. The effectiveness of the proposed method is verified by simulating a dual-spool turbofan engine on a nonlinear component level model and comparing the proposed method with the gain scheduling based on PI and H∞ point design.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87906093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-31DOI: 10.3390/aerospace10090778
James Blaise, Michael C. F. Bazzocchi
Recent efforts in on-orbit servicing, manufacturing, and debris removal have accentuated some of the challenges related to close-proximity space manipulation. Orbital debris threatens future space endeavors driving active removal missions. Additionally, refueling missions have become increasingly viable to prolong satellite life and mitigate future debris generation. The ability to capture cooperative and non-cooperative spacecraft is an essential step for refueling or removal missions. In close-proximity capture, collision avoidance remains a challenge during trajectory planning for space manipulators. In this research, a deep reinforcement learning control approach is applied to a three-degrees-of-freedom manipulator to capture space objects and avoid collisions. This approach is investigated in both free-flying and free-floating scenarios, where the target object is either cooperative or non-cooperative. A deep reinforcement learning controller is trained for each scenario to effectively reach a target capture location on a simulated spacecraft model while avoiding collisions. Collisions between the base spacecraft and the target spacecraft are avoided in the planned manipulator trajectories. The trained model is tested for each scenario and the results for the manipulator and base motion are detailed and discussed.
{"title":"Space Manipulator Collision Avoidance Using a Deep Reinforcement Learning Control","authors":"James Blaise, Michael C. F. Bazzocchi","doi":"10.3390/aerospace10090778","DOIUrl":"https://doi.org/10.3390/aerospace10090778","url":null,"abstract":"Recent efforts in on-orbit servicing, manufacturing, and debris removal have accentuated some of the challenges related to close-proximity space manipulation. Orbital debris threatens future space endeavors driving active removal missions. Additionally, refueling missions have become increasingly viable to prolong satellite life and mitigate future debris generation. The ability to capture cooperative and non-cooperative spacecraft is an essential step for refueling or removal missions. In close-proximity capture, collision avoidance remains a challenge during trajectory planning for space manipulators. In this research, a deep reinforcement learning control approach is applied to a three-degrees-of-freedom manipulator to capture space objects and avoid collisions. This approach is investigated in both free-flying and free-floating scenarios, where the target object is either cooperative or non-cooperative. A deep reinforcement learning controller is trained for each scenario to effectively reach a target capture location on a simulated spacecraft model while avoiding collisions. Collisions between the base spacecraft and the target spacecraft are avoided in the planned manipulator trajectories. The trained model is tested for each scenario and the results for the manipulator and base motion are detailed and discussed.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89536706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-30DOI: 10.3390/aerospace10090768
Junfeng Wu, Haiquan Wang, Shanshan Li, Shuguang Liu
This paper investigates the distance-based formation and cooperative path-following control problems for multiple fixed-wing unmanned aerial vehicles (UAVs). In this study, we design the distance-based formation control structure to achieve the virtual leader and followers pre-defined rigid formation pattern, ensuring simultaneously relative localization. A path-following control strategy based on adaptive dynamic surface and neural network control technology is proposed to approximate the uncertain disturbances of the environment and unmodeled dynamics. And the longitudinal and lateral subsystems’ adaptive fault-tolerant controllers are designed, respectively, to achieve the fault-tolerant control of UAVs’ formation in three-dimensional environments. Furthermore, the adaptive sliding mode controller with an auxiliary controller is designed to realize the UAVs path following with limited input saturation. Finally, simulation examples are given to clarify and verify the effectiveness of the theoretical results.
{"title":"Distributed Adaptive Path-Following Control for Distance-Based Formation of Fixed-Wing UAVs under Input Saturation","authors":"Junfeng Wu, Haiquan Wang, Shanshan Li, Shuguang Liu","doi":"10.3390/aerospace10090768","DOIUrl":"https://doi.org/10.3390/aerospace10090768","url":null,"abstract":"This paper investigates the distance-based formation and cooperative path-following control problems for multiple fixed-wing unmanned aerial vehicles (UAVs). In this study, we design the distance-based formation control structure to achieve the virtual leader and followers pre-defined rigid formation pattern, ensuring simultaneously relative localization. A path-following control strategy based on adaptive dynamic surface and neural network control technology is proposed to approximate the uncertain disturbances of the environment and unmodeled dynamics. And the longitudinal and lateral subsystems’ adaptive fault-tolerant controllers are designed, respectively, to achieve the fault-tolerant control of UAVs’ formation in three-dimensional environments. Furthermore, the adaptive sliding mode controller with an auxiliary controller is designed to realize the UAVs path following with limited input saturation. Finally, simulation examples are given to clarify and verify the effectiveness of the theoretical results.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88249524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-29DOI: 10.3390/aerospace10090766
Xinyi Liu, Zhen-bing Luo, Qiang Liu, Pan Cheng, Yan Zhou
Transition delaying is of great importance for the drag and heat flux reduction of hypersonic flight vehicles. The first mode, with low frequency, and the second mode, with high frequency, exist simultaneously during the transition through the hypersonic boundary layer. This paper proposes a novel bi-frequency synthetic jet to suppress low- and high-frequency disturbances at the same time. Orthogonal table and variance analyses were used to compare the control effects of jets with different positions (USJ or DSJ), low frequencies (f1), high frequencies (f2), and amplitudes (a). Linear stability analysis results show that, in terms of the growth rate varying with the frequency of disturbance, an upstream synthetic jet (USJ) with a specific frequency and amplitude can hinder the growth of both the first and second modes, thereby delaying the transition. On the other hand, a downstream synthetic jet (DSJ), regardless of other parameters, increases flow instability and accelerates the transition, with higher frequencies and amplitudes resulting in greater growth rates for both modes. Low frequencies had a significant effect on the first mode, but a weak effect on the second mode, whereas high frequencies demonstrated a favorable impact on both the first and second modes. In terms of the growth rate varying with the spanwise wave number, the control rule of the same parameter under different spanwise wave numbers was different, resulting in a complex pattern. In order to obtain the optimal delay effect upon transition and improve the stability of the flow, the parameters of the bi-synthetic jet should be selected as follows: position it upstream, with f1 = 3.56 kHz, f2 = 89.9 kHz, a = 0.009, so that the maximum growth rate of the first mode is reduced by 9.06% and that of the second mode is reduced by 1.28% compared with the uncontrolled state, where flow field analysis revealed a weakening of the twin lattice structure of pressure pulsation.
{"title":"Numerical Investigation of Hypersonic Flat-Plate Boundary Layer Transition Subjected to Bi-Frequency Synthetic Jet","authors":"Xinyi Liu, Zhen-bing Luo, Qiang Liu, Pan Cheng, Yan Zhou","doi":"10.3390/aerospace10090766","DOIUrl":"https://doi.org/10.3390/aerospace10090766","url":null,"abstract":"Transition delaying is of great importance for the drag and heat flux reduction of hypersonic flight vehicles. The first mode, with low frequency, and the second mode, with high frequency, exist simultaneously during the transition through the hypersonic boundary layer. This paper proposes a novel bi-frequency synthetic jet to suppress low- and high-frequency disturbances at the same time. Orthogonal table and variance analyses were used to compare the control effects of jets with different positions (USJ or DSJ), low frequencies (f1), high frequencies (f2), and amplitudes (a). Linear stability analysis results show that, in terms of the growth rate varying with the frequency of disturbance, an upstream synthetic jet (USJ) with a specific frequency and amplitude can hinder the growth of both the first and second modes, thereby delaying the transition. On the other hand, a downstream synthetic jet (DSJ), regardless of other parameters, increases flow instability and accelerates the transition, with higher frequencies and amplitudes resulting in greater growth rates for both modes. Low frequencies had a significant effect on the first mode, but a weak effect on the second mode, whereas high frequencies demonstrated a favorable impact on both the first and second modes. In terms of the growth rate varying with the spanwise wave number, the control rule of the same parameter under different spanwise wave numbers was different, resulting in a complex pattern. In order to obtain the optimal delay effect upon transition and improve the stability of the flow, the parameters of the bi-synthetic jet should be selected as follows: position it upstream, with f1 = 3.56 kHz, f2 = 89.9 kHz, a = 0.009, so that the maximum growth rate of the first mode is reduced by 9.06% and that of the second mode is reduced by 1.28% compared with the uncontrolled state, where flow field analysis revealed a weakening of the twin lattice structure of pressure pulsation.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79733803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-29DOI: 10.3390/aerospace10090765
Xiaojun Yu, Shi-shi Luo, Haiqiao Liu
Focusing on the large maneuver penetration of the hypersonic glide vehicle with multiple constraints and uncertain disturbance, a robust integrated guidance and control law, which can achieve the snake-shape maneuver, is designed. A snake-shape maneuver acceleration command, in the framework of sine function, determined by the altitude, target declination of the line of sight and the missile-target distance, is discussed. The integrated guidance and control law includes the terminal guidance law with multiple constraints, attitude control law and angular velocity control law. In the terminal guidance law design, the sliding mode control is adopted while the adaptive technique is applied to estimate the disturbance. The selected sliding mode surface has variable gain determined by the estimated time-to-go. With the designed terminal guidance law, using the snake-shape maneuver acceleration command as the bias item, the angular rate of the line of sight will converge to zero and the line of sight angle will converge to the expected value, simultaneously. The attitude control law and angular velocity control law are designed to track the expected attack and bank angles. The stability of the whole system is proved with the application of the Lyapunov theorem. The effectiveness and robustness of the proposed integrated guidance and control law is verified by simulation.
{"title":"Integrated Design of Multi-Constrained Snake Maneuver Surge Guidance Control for Hypersonic Vehicles in the Dive Segment","authors":"Xiaojun Yu, Shi-shi Luo, Haiqiao Liu","doi":"10.3390/aerospace10090765","DOIUrl":"https://doi.org/10.3390/aerospace10090765","url":null,"abstract":"Focusing on the large maneuver penetration of the hypersonic glide vehicle with multiple constraints and uncertain disturbance, a robust integrated guidance and control law, which can achieve the snake-shape maneuver, is designed. A snake-shape maneuver acceleration command, in the framework of sine function, determined by the altitude, target declination of the line of sight and the missile-target distance, is discussed. The integrated guidance and control law includes the terminal guidance law with multiple constraints, attitude control law and angular velocity control law. In the terminal guidance law design, the sliding mode control is adopted while the adaptive technique is applied to estimate the disturbance. The selected sliding mode surface has variable gain determined by the estimated time-to-go. With the designed terminal guidance law, using the snake-shape maneuver acceleration command as the bias item, the angular rate of the line of sight will converge to zero and the line of sight angle will converge to the expected value, simultaneously. The attitude control law and angular velocity control law are designed to track the expected attack and bank angles. The stability of the whole system is proved with the application of the Lyapunov theorem. The effectiveness and robustness of the proposed integrated guidance and control law is verified by simulation.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88465548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-29DOI: 10.3390/aerospace10090767
Zhuopu Wang, Wenchao Zhang, Yuanzhe Liu
Solid rocket motors are prone to combustion instabilities, which may lead to various problems for the rockets, from unexpected oscillations, precision decreasing, to explosion. The unsteady combustion dynamics of the propellants play a crucial role in most solid rocket motors experiencing combustion instabilities. A modeling framework for the unsteady combustion of the solid propellant is constructed via the Zel’dovich-Novozhilov (ZN) phenomenological perspective. The overall unsteady combustion features of a quasi-steady homogeneous one-dimensional (QSHOD) model are investigated. The phenomenological ZN parameters are then calculated. Compared with the traditional ZN-QSHOD linear equivalence relation, the new calculated system yields better results for the pressure coupling response, especially in the non-linear regime. The proposed phenomenological modeling provides a new methodology for the model reduction of the complex flame models.
{"title":"A Phenomenological Model for the Unsteady Combustion of Solid Propellants from a Zel’dovich-Novzhilov Approach","authors":"Zhuopu Wang, Wenchao Zhang, Yuanzhe Liu","doi":"10.3390/aerospace10090767","DOIUrl":"https://doi.org/10.3390/aerospace10090767","url":null,"abstract":"Solid rocket motors are prone to combustion instabilities, which may lead to various problems for the rockets, from unexpected oscillations, precision decreasing, to explosion. The unsteady combustion dynamics of the propellants play a crucial role in most solid rocket motors experiencing combustion instabilities. A modeling framework for the unsteady combustion of the solid propellant is constructed via the Zel’dovich-Novozhilov (ZN) phenomenological perspective. The overall unsteady combustion features of a quasi-steady homogeneous one-dimensional (QSHOD) model are investigated. The phenomenological ZN parameters are then calculated. Compared with the traditional ZN-QSHOD linear equivalence relation, the new calculated system yields better results for the pressure coupling response, especially in the non-linear regime. The proposed phenomenological modeling provides a new methodology for the model reduction of the complex flame models.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82813018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-28DOI: 10.3390/aerospace10090760
L. Campos, Manuel J. S. Silva
The safety zone around the flight path of a rocket is determined by the fall of debris in the case of an accidental explosion or commanded termination. The trajectory of a tumbling body in a vertical plane is determined by specifying the velocity, flight path angle and angle of attack as functions of time. This involves the lift, drag and pitching moment coefficients as functions of the angle of attack over a full circle—0 to 360 degrees—to account for the tumbling motion. The problem is reduced to a third-order non-linear differential equation for the angle of attack by using the approximation of free fall coordinates. The analytical and numerical solutions show that two types of tumbling fall are possible, one with rotation and the other with oscillation. The tumbling trajectories are plotted and discussed for a variety of initial conditions, mass and aerodynamic properties of the tumbling body.
{"title":"On the Size of the Safety Area around the Launch Trajectory of a Rocket","authors":"L. Campos, Manuel J. S. Silva","doi":"10.3390/aerospace10090760","DOIUrl":"https://doi.org/10.3390/aerospace10090760","url":null,"abstract":"The safety zone around the flight path of a rocket is determined by the fall of debris in the case of an accidental explosion or commanded termination. The trajectory of a tumbling body in a vertical plane is determined by specifying the velocity, flight path angle and angle of attack as functions of time. This involves the lift, drag and pitching moment coefficients as functions of the angle of attack over a full circle—0 to 360 degrees—to account for the tumbling motion. The problem is reduced to a third-order non-linear differential equation for the angle of attack by using the approximation of free fall coordinates. The analytical and numerical solutions show that two types of tumbling fall are possible, one with rotation and the other with oscillation. The tumbling trajectories are plotted and discussed for a variety of initial conditions, mass and aerodynamic properties of the tumbling body.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81225036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2023-08-28DOI: 10.3390/aerospace10090761
Yongtao Lyu, Yibiao Niu, Tao He, Limin Shu, Michael Zhuravkov, Shutao Zhou
In this paper, a new method using the backpropagation (BP) neural network combined with the improved genetic algorithm (GA) is proposed for the inverse design of thin-walled reinforced structures. The BP neural network model is used to establish the mapping relationship between the input parameters (reinforcement type, rib height, rib width, skin thickness and rib number) and the output parameters (structural buckling load). A genetic algorithm is added to obtain the inversely designed result of a thin-wall stiffened structure according to the actual demand. In the end, according to the geometric parameters of inverse design, the thin-walled stiffened structure is reconstructed geometrically, and the numerical solutions of finite element calculation are compared with the target values of actual demand. The results show that the maximal inversely designed error is within 5.1%, which implies that the inverse design method of structural geometric parameters based on the machine learning and genetic algorithm is efficient and feasible.
{"title":"An Efficient Method for the Inverse Design of Thin-Wall Stiffened Structure Based on the Machine Learning Technique","authors":"Yongtao Lyu, Yibiao Niu, Tao He, Limin Shu, Michael Zhuravkov, Shutao Zhou","doi":"10.3390/aerospace10090761","DOIUrl":"https://doi.org/10.3390/aerospace10090761","url":null,"abstract":"In this paper, a new method using the backpropagation (BP) neural network combined with the improved genetic algorithm (GA) is proposed for the inverse design of thin-walled reinforced structures. The BP neural network model is used to establish the mapping relationship between the input parameters (reinforcement type, rib height, rib width, skin thickness and rib number) and the output parameters (structural buckling load). A genetic algorithm is added to obtain the inversely designed result of a thin-wall stiffened structure according to the actual demand. In the end, according to the geometric parameters of inverse design, the thin-walled stiffened structure is reconstructed geometrically, and the numerical solutions of finite element calculation are compared with the target values of actual demand. The results show that the maximal inversely designed error is within 5.1%, which implies that the inverse design method of structural geometric parameters based on the machine learning and genetic algorithm is efficient and feasible.","PeriodicalId":50845,"journal":{"name":"Aerospace America","volume":null,"pages":null},"PeriodicalIF":0.1,"publicationDate":"2023-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86504198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：