Dynamic inverse control of feedback linearization in ballistic correction based on nose cone swinging

It is a complicated nonlinear controlling problem to conduct a two-dimensional trajectory correction of rockets.By establishing the aerodynamic correction force mathematical model of rockets on nose cone swinging,the linear control is realized by the dynamic inverse nonlinear controlling theory and the three-time-scale separation method.The control ability and the simulation results are also tested and verified.The results show that the output responses of system track the expected curve well and the error is controlled in a given margin.The maximum correction is about±314 m in the lengthwise direction and±1 212 m in the crosswise direction from the moment of 5 s to the drop-point time when the angle of fire is 55°.Thus,based on the dynamic inverse control of feedback linearization,the trajectory correction capability of nose cone swinging can satisfy the requirements of two-dimensional ballistic correction,and the validity and effectiveness of the method are proved.

Thermochemical ablation of spherical cone during re-entry

Presents the use of the similar transform and potential theory for calculation of the bypass flow factor and pressure gradient and the analysis of the influence of bypass flow factor and pressure gradient on heat transfer is analyzed, and the distribution of nose cone ablation obtained by combining the controlling equations of boundary layer, the compatible relation of interface and the heat conduction of interior.

Design and Analysis of Biomimetic Nose Cone for Morphing of Aerospace Vehicle

Morphing capability is absolutely vital for aerospace vehicle to gain predominant functions of aerodynamics, mobility and flight control while piercing and re-entering the atmosphere. However, the challenge for existing aerospace vehicle remains to change its structure of nose cone agilely. This paper carries out a lot of observational experiments on honeybee＇s abdomen which enhances the flight characteristics of honeybee by adjusting its biomorphic shape. A morphing structure is adopted from honeybee＇s abdomen to improve both the axial scalability and bending properties of aerospace vehicle, which can lead to the super-maneuver flight performance. Combined with the methods of optimum design and topology, a new bionic morphing structure is proposed and applied to the design of morphing nose cone of aerospace vehicle. Furthermore, simulations are conducted to optimize the structural parameters of morphing nose cone. This concept design of biomimetic nose cone will provide an efficient way for aerospace vehicle to reduce the aerodynamic drag.

Experimental investigations on structural improvement of morphing mechanism for nose cone of aerospace vehicle adopting a bionic redundant constraint strategy

Aerospace vehicles have recently received great attention for their completely reusable in aviation and aerospace.To achieve the optimal aerodynamic performance of the aerospace vehicle,the nose cone needs to change its aerodynamic shape under different flight conditions.However,the structural design of a morphing nose cone that is capable of changing aerodynamic shape adaptively and withstanding prescribed aerodynamic loads remains an ongoing challenge.To overcome this issue and to further advance our previous work,the motion performance of a morphing nose cone inspired by the deformation mechanism of the honeybee abdomen was tested to evaluate the deformation ability and bearing capacity.The dynamic prediction analysis of the morphing nose cone with a clearance joint and flexible links was then investigated to elucidate the crucial issues in the deformation movement.To improve the motion performance,a performance improvement scheme based on redundant constraints drawn from the muscle distribution of the honeybee abdomen was proposed.Finally,the structural stiffness,dynamic analysis,and experimental testing of the improved morphing nose cone were conducted.The experimental results indicate that the extension and contraction ratios and bending angles of the improved morphing nose cone under loads of 0,10,and 25 kg loads improve by 1.51%and 2.329°,2.78%and-1.902°,and 5.06%and 1.111°,respectively,verifying the rationality and effectiveness of the performance improvement scheme.This work provides a new reference for the design of the morphing structure for aerospace vehicles.

Design and optimization of a longitudinal feedback kicker cavity for the HLS-Ⅱ storage ring

In the Hefei Light Source （HLS） storage ring, multibunch operation is used to obtain a high luminosity. Multibunch instabilities can severely limit light source performance with a variety of negative impacts, including beam loss, low injection efficiency, and overall degradation of the beam quality. Instabilities of a multibunch beam can be mitigated using certain techniques including increasing natural damping （operating at a higher energy）, lowering the beam current, and increasing Landau damping. However, these methods are not adequate to stabilize a multibunch electron beam at a low energy and with a high current. In order to combat beam instabilities in the HLS storage ring, active feedback systems including a longitudinal feedback system （LFB） and a transverse feedback system （TFB） will be developed as part of the HLS upgrade project, the HLS-Ⅱ storage ring project. As a key component of the longitudinal bunch-by-bunch feedback system, an LFB kicker cavity with a wide bandwidth and high shunt impedance is required. In this paper we report our work on the design of the LFB kicker cavity for the HLS-Ⅱ storage ring and present the new tuning and optimization techniques developed in designing this high performance LFB kicker.