Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering最新文献

{"title":"Role of strut shape on the generation of internal side force and moments in A supersonic nozzle with strut insertion through diverging wall","authors":"Lakshmi Srinivas A, Sridhar BTN","doi":"10.1177/09544100241260109","DOIUrl":"https://doi.org/10.1177/09544100241260109","url":null,"abstract":"Cold flow experiments were conducted on a convergent-divergent (C-D) nozzle with a strut inserted through the nozzle diverging wall to study the internal wall pressure distribution. The objective of the work was to calculate the internal side force and hence the pitching moment generated as a consequence of the side insertion of the strut through the nozzle wall. The generation of side force/pitching moment would be useful for the development of a potential alternative thrust vector control system of flight vehicles employing a supersonic nozzle. The strut was inserted at a distance of 2/3<jats:sup>rd</jats:sup> of the diverging section length ( L<jats:sub> d</jats:sub>) of the nozzle from the throat. Two cross sectional shapes of the strut i.e. square with V-notch and semi-ellipse were employed in the experiments. Eight wall pressure ports each on the strut side and on counter strut side of the nozzle axis were used to acquire the pressure data. The design exit Mach number ( M<jats:sub> d</jats:sub>) corresponding to isentropic flow conditions of the nozzle was 1.84 with an area ratio of 1.48. The cold flow experiments were conducted at three nozzle pressure ratios (NPRs) which were 3.4,5 (both corresponded to over-expansion) and 6.9 (under-expansion). For each strut shape and at a given NPR, strut height ( h<jats:sub> s</jats:sub>) was varied to study the internal wall pressure distribution. The maximum height of the strut was restricted to the radius of the local cross section of the nozzle (r) where the strut was inserted. From the wall pressure ( p<jats:sub> w</jats:sub>) distribution, two-dimensional side force ( C<jats:sub> s</jats:sub>) and moment coefficients ( C<jats:sub> m</jats:sub>) were calculated. The variation of these coefficients with h<jats:sub> s</jats:sub> was plotted and the effect of the strut shape for each operational NPR was studied. These variations with h<jats:sub> s</jats:sub> in respect of square-notch shape and semi elliptical shape were also compared with variations corresponding to square shape available in the literature. The variations of C<jats:sub> s</jats:sub> and C<jats:sub> m</jats:sub> were highly nonlinear and trends of both the variations were similar. It was observed from these variations that the semi-elliptical strut shape exhibited a distinct behavior which was in contrast to two other shapes. Variation in h<jats:sub> s</jats:sub> resulted in both positive and negative values of coefficients in respect of square with V-notch and square shaped struts, whereas in case of semi-elliptical shape mostly positive values of the coefficients were observed. The maximum positive magnitude of C<jats:sub> s</jats:sub> was observed at strut heights which were 27% and 57% of the local radius of the nozzle cross section (where the strut was inserted) for square with V-notch and semi-elliptical struts respectively.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738824","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}

{"title":"Robust attitude trajectory tracking control for a quadrotor under external disturbance","authors":"Tianpeng Huang, Junxiao Ren, Liang Li, Huishuang Shao, Tao Yu","doi":"10.1177/09544100241262689","DOIUrl":"https://doi.org/10.1177/09544100241262689","url":null,"abstract":"Attitude stability plays an important role in quadrotor aircraft. However, it is difficult to design a robust controller to precisely track a desired attitude trajectory in the presence of external disturbance. To address this problem, a nonlinear disturbance estimator with finite-time convergence is proposed to estimate external disturbance. Then, a dynamic surface control scheme based on the disturbance estimator is developed. Therefore, the compensation for external disturbance can be achieved in the designed controller. Furthermore, the L<jats:sub> ∞</jats:sub> performance of transient attitude tracking error is achieved by analyzing solution of Lyapunov function. The finite-time convergence of disturbance estimation error and the asymptotical convergence of attitude tracking error of closed-loop system are rigorously proved. Finally, the numerical simulations are carried out to demonstrate the effectiveness of the developed disturbance estimator and control scheme.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505851","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}

{"title":"Design and aerodynamic characteristics of variable-geometry hypersonic inlet based on shock wave elimination","authors":"Guangwei Wu, Ziao Wang, Fuxu Quan, Juntao Chang","doi":"10.1177/09544100241263896","DOIUrl":"https://doi.org/10.1177/09544100241263896","url":null,"abstract":"To solve the problem that the control of shock wave elimination is weakened under off-design conditions, the design concept of a variable-geometry inlet scheme that combines the variable-geometry cowl (translating and diagonalizing) with regulating shock wave elimination is introduced in this paper. The variable-geometry inlet is designed by the theories of oblique shock wave and isentropic wave as well as the Oswatitsch theory. Regulatory law of the variable-geometry cowl based on shock wave elimination is obtained by the geometric relationships between cowl compression angle, cowl shock wave angle, and optimal control point or range. Numerical simulations are conducted to investigate flow field characteristics, control mechanism, and working performance of the inlet. Results reveal that expansion waves have a significant impact on the cowl shock wave and boundary layer interaction, and flow separation. Furthermore, variable-geometry inlet with translating and diagonalizing cowl based on the regulation of shock wave elimination effectively controls and even completely eliminates the flow separation. In terms of inlet performance, the total pressure loss of the variable-geometry inlet decreases such that the total pressure recovery coefficients of the translating cowl and diagonalizing cowl inlets are increased by maximum values of 3.39 % and 9.97 %, respectively. However, the mass flow coefficient of translating cowl inlet decreases, whereas that of the diagonalizing cowl inlet is equivalent to that of the fixed-geometry inlet. The working range can be widened by changing the internal contract ratio of the inlet through translating or diagonalizing the cowl. The results confirm that the scheme of variable geometry inlet with diagonalizing cowl is practicable and reliable and has important guiding significance and value for inlet design.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505849","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}

{"title":"Effect of injector on flow characteristic and hydraulic performance in aero-fuel centrifugal pump","authors":"Jia Li, Bo Liu, Wen Zhou, Jian Xie, Xuan Chen","doi":"10.1177/09544100241263024","DOIUrl":"https://doi.org/10.1177/09544100241263024","url":null,"abstract":"In the fuel system of an aircraft engine, aero-fuel centrifugal pumps are widely utilized as boost pumps. In this research, we propose the integration of an inlet injector with an aero-fuel centrifugal pump to optimize its flow characteristics and enhance performance. The key geometric parameters of the impeller, volute, and injector are meticulously designed. The effectiveness of our approach is validated through a combination of experimental and numerical analysis, which involves comparing simulation results with experimental data. The findings demonstrate that the presence of the injector significantly impacts the flow characteristics and hydraulic performance of the pump. Specifically, it effectively reduces flow losses in the specific channels of the impeller and volute. Furthermore, the injector enhances the regulation of the inlet flow fields by adjusting the inlet pressure and controlling the suction flow direction. Consequently, the pump’s efficiency is enhanced when equipped with the injector compared to its performance without it. Therefore, incorporating an injector in an aero-fuel centrifugal pump has a positive effect on regulating flow characteristics and improving hydraulic efficiency.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505850","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}

{"title":"Desensitized optimal trajectory for hopping rovers on small bodies","authors":"Shengying Zhu, Chuncheng Zhao","doi":"10.1177/09544100241262559","DOIUrl":"https://doi.org/10.1177/09544100241262559","url":null,"abstract":"Future exploration tasks of small bodies will need to sample or visit multiple points on the target to obtain more scientific returns, requiring rovers to have the ability to hop on a small body surface. This paper proposes an approach to generate a desensitized optimal trajectory for hopping rovers, aiming at reducing the sensitivity of hopping trajectory in the presence of uncertainties. Firstly, considering parameter uncertainties and initial state errors, analytical expressions of optimal initial states are derived on a planar scene, based on ballistic dynamics. Then, similar methods are developed in both uphill and downhill cases of inclined scenes. Subsequently, the desensitization performance of long-distance hopping trajectory is analyzed under single-hop, identical, and non-identical N-hop strategies. To facilitate the application of the proposed analytical solution to the simulated surface environment of small bodies, a prediction-correction procedure is presented. Finally, Monte Carlo simulations are carried out to verify the effectiveness of the proposed methods. The results indicate that the sensitivity of the hopping trajectory to uncertainties can be effectively diminished by employing the desensitized optimal trajectory and multiple hopping strategy.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513870","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}

{"title":"Control stability analysis of dynamic model with time delay for quadrotor UAV","authors":"Xi Li, Guoyuan Qi, Limin Zhang","doi":"10.1177/09544100241262550","DOIUrl":"https://doi.org/10.1177/09544100241262550","url":null,"abstract":"For the first-order unstable object with time delay, the PD control parameter tuning method based on the traditional definition lacks consideration of the lower boundary of amplitude margin, resulting in a certain deviation between the result and the reality. In this paper, through analyzing the control loop of quadrotor UAV (QUAV), the integral link is moved from the controlled object to the controller, and the QUAV becomes a first-order unstable object, realizing the conversion of PD to PI in the hovering state. The system stability margin remains unchanged, and the position and attitude control objectives can be realized synchronously. By means of parameter setting method, the upper boundary of stability margin is obtained. Pade approximation is carried out for the time delay link, and then the lower margin of the amplitude margin is deduced according to Routh stability criterion, so as to obtain a more accurate reachable stability margin region. To avoid the high gain feedback of attitude angular velocity of QUAV, a numerical analytical setting formula for PD attitude control is derived to meet the requirements of gain and phase margin. The graph shows that the reachable region obtained by the strict definition of stability margin analysis decreases significantly. The proposed method can not only give the reachable region intuitively, but also give the tuning formula of the control parameters concisely, which has important engineering application value.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141513869","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}

{"title":"Angular acceleration estimation and aerodynamic parameter identification based on angular velocity equivalent model","authors":"Lixin Wang, Rong Zhao, Yi Zhang, Ting Yue","doi":"10.1177/09544100241249350","DOIUrl":"https://doi.org/10.1177/09544100241249350","url":null,"abstract":"Conventional angular acceleration estimation methods generate non-negligible errors when the control surface rapidly deflects; hence, the estimated angular acceleration cannot be used for aerodynamic parameter identification directly. This paper proposes an angular acceleration estimation method based on angular velocity equivalent model. The angular acceleration of the angular velocity equivalent model, whose angular velocity response is consistent with the flight test data, is used as the estimated angular acceleration. Firstly, the equivalent angular velocity model is established by combining the generic aerodynamic model with the rotational dynamic equations of aircraft. Secondly, the angular velocity data and the control surface deflection data are synchronized. Finally, the angular velocity response of the equivalent model is used as the predictor, and the estimated angular acceleration is obtained by extended Kalman filter. The aerodynamic parameter identification and validation are carried out using the estimated angular acceleration of a large civil aircraft flight test data. The results show that the angular acceleration obtained through the proposed angular acceleration estimation method meets the accuracy requirement of aerodynamic parameter identification.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140936246","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}

{"title":"Drone path planning and dynamic arena-target allocation for crowd surveillance","authors":"Onkar Chopra, Samiksha Rajkumar Nagrare, Shuvrangshu Jana, Debasish Ghose","doi":"10.1177/09544100241253646","DOIUrl":"https://doi.org/10.1177/09544100241253646","url":null,"abstract":"The paper addresses the problem of surveillance of dynamic crowds in a bounded arena using multiple drones. The strategy proposes a prediction-based path planning approach for drones, where the target’s future position is predicted and used to generate a traverse path. The procedure for grouping numerous human beings in order to deal with a dense crowd scenario is also described. An algorithm to dynamically divide and allocate the arena to drones is also proposed to ensure equal workload distribution among all drones in the framework. The paper also discusses relevant concepts like detecting anomalous crowd activity and searching for any missing target in the arena. The proposed algorithms are validated on MATLAB environment numerically and ROS/Gazebo physics engine as a part of simulation-in-the-loop (SITL).","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140936433","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}

{"title":"Aeroelastic analysis of a lightweight topology-optimized sandwich panel","authors":"Maliheh Najafi, António J. M. Ferreira, Flávio D. Marques","doi":"10.1177/09544100241252041","DOIUrl":"https://doi.org/10.1177/09544100241252041","url":null,"abstract":"Sandwich structures with lattice cores are novel, lightweight composite structures and are widely used in the aerospace industry. Besides, the aeroelastic behavior of sandwich panels in a supersonic flow regime still needs to be thoroughly studied. This work investigates the supersonic flutter of a sandwich panel whose core is topology-optimized. A finite element model of a sandwich panel based on the layerwise theory, coupled with the first-order piston theory, is presented. The sandwich panel core is assessed using a topology optimization approach with flutter loading constraints. The subsequent analytical homogenization scheme is developed to provide the equivalent mechanical properties of the topology-optimized panel. The modeling approach is fully validated, and the results demonstrate that the sandwich panel is capable of enlarging the flutter-free operational flight range when compared with other conventional panel designs. A parametric analysis of the topology-optimized sandwich panel regarding the critical flutter conditions is performed.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140936251","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}

{"title":"Optimal impact angle guidance law with barrier constraint","authors":"Cheol-Goo Jung, Pengyu Wang, Chang-Hun Lee","doi":"10.1177/09544100241252864","DOIUrl":"https://doi.org/10.1177/09544100241252864","url":null,"abstract":"This paper presents an optimal guidance law for missile to achieve desired impact angles on a stationary target while accommodating the barrier constraint. The proposed guidance law consists of two parts: a baseline guidance command for intercepting the target with desired impact angles, and a bias command to prevent collision with the barrier. Specifically, the baseline guidance command is derived by solving a linearized optimal control problem, and its explicit trajectory solution is also obtained for collision estimation. The bias command is designed using a novel guidance error that is defined based on the geometrical relationship between the barrier and the proposed explicit trajectory solution. The new guidance law can be easily implemented to a variety of practical engagement geometries, resulting in successful collision avoidance and minimal control efforts. Its effectiveness and robustness are demonstrated via extensive numerical simulations.","PeriodicalId":54566,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers Part G-Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140941897","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}