scholarly journals Rapid trajectory planning of a reusable launch vehicle for airdrop with geographic constraints

2019 ◽  
Vol 16 (1) ◽  
pp. 172988141881797 ◽  
Author(s):  
Xing Wei ◽  
Xuejing Lan ◽  
Lei Liu ◽  
Yongji Wang
Keyword(s):  
Trajectory Planning ◽  
Planning Process ◽  
Launch Vehicle ◽  
Search Problem ◽  
Quasi Equilibrium ◽  
Bank Angle ◽  
Weighted Interpolation ◽  
Reusable Launch Vehicle ◽  
Terminal Constraints ◽  
Planning Algorithm

Online feasible trajectory generation for an airdrop unpowered reusable launch vehicle is addressed in this article. A rapid trajectory planning algorithm is proposed to satisfy not only the multiple path and terminal constraints but also the complex geographic constraints of waypoints and no-fly zones. Firstly, the lower and upper boundaries of the bank angle that implement all the path constraints are obtained based on the quasi-equilibrium glide condition. To determine the bank angle directly, a weighted interpolation of the boundaries is then developed, which provides an effective approach to simplify the planning process as a one-parameter search problem. Subsequently, three types of lateral planning algorithms are designed to determine the sign of the bank angle according to the requirements of waypoints passage, no-fly-zones avoidance, and terminal constraints in the airdrop process, and the convergence of these methods for passing over the waypoints and meeting the terminal conditions has been clarified and formally demonstrated. Considering the constraints in the actual airdrop flight missions, the planning trajectory is divided into several subphases to facilitate the application of corresponding algorithms. Finally, the performance of the proposed algorithm is assessed through three airdrop missions of reusable launch vehicle with different geographic constraints. Besides, the effectiveness of the algorithm is demonstrated by the Monte Carlo simulation results.

Terminal Area Energy Management Trajectory Planning for an Unpowered Reusable Launch Vehicle with Gliding Limitations

2013 ◽  
Vol 446-447 ◽  
pp. 611-615
Author(s):  
Min Zhou ◽  
Jun Zhou ◽  
Jian Guo Guo
Keyword(s):  
Trajectory Planning ◽  
Closed Loop ◽  
Dynamic Pressure ◽  
Open Loop ◽  
Bank Angle ◽  
Reference Velocity ◽  
Reusable Launch Vehicle ◽  
Planning Algorithm ◽  
Constant Maximum ◽  
Terminal Area

RLVs' gliding capability, determined by its maximum dive and maximum range, provided a significant restriction in TAEM trajectory planning in this paper. The maximum-dive trajectory was generated based on Eq.(3) for a constant maximum dynamic pressure. In the guidance, it was optimized to be Eq.(13) for the open-loop command of bank angle in HAC segment. The simplified closed-loop command of angle of attack contained errors of altitude and path angle except the controlled velocity. Energy propagating as Eq.(8) calculated the reference velocity for the speed brake to track. Finally, an illustrative example was given to confirm the efficiency of the trajectory planning algorithm and optimized command. The simulation results in Fig.2 and Fig.3 indicate the proposed trajectory planning algorithm and guidance method are useful for the gliding capability limited RLV's TAEM with initial deviations.

scholarly journals Guidance Law Design for Terminal Area Energy Management of Reusable Launch Vehicle by Energy-to-Range Ratio

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wen Jiang ◽  
Zhaohua Yang
Keyword(s):  
Energy Management ◽  
Trajectory Planning ◽  
Launch Vehicle ◽  
Reference Trajectory ◽  
Tracking Errors ◽  
Guidance Law ◽  
Reusable Launch Vehicle ◽  
Planning Algorithm ◽  
Flight Profile ◽  
Terminal Area

A new guidance scheme that utilizes a trajectory planning algorithm by energy-to-range ratio has been developed under the circumstance of surplus energy for the terminal area energy management phase of a reusable launch vehicle. The trajectory planning scheme estimates the reference flight profile by piecing together several flight phases that are defined by a set of geometric parameters. Guidance commands are readily available once the best reference trajectory is determined. The trajectory planning algorithm based on energy-to-range ratio is able to quickly generate new reference profiles for testing cases with large variations in initial vehicle condition and energy. The designed flight track has only one turn heading, which simplifies the trajectory planning algorithm. The effectiveness of the trajectory planning algorithm is demonstrated by simulations, which shows that the guided vehicle is able to successfully dissipate energy and reach the desired approach and landing glideslope target with small tracking errors.

Semi-analytical terminal and automatic approach and landing trajectory planners for unpowered reusable launch vehicle

2019 ◽  
Author(s):  
◽  
Fawaz Al Bakri
Keyword(s):  
Initial Conditions ◽  
Equations Of Motion ◽  
Launch Vehicle ◽  
Computational Time ◽  
Geometrical Parameters ◽  
Quasi Equilibrium ◽  
Bank Angle ◽  
Ground Track ◽  
Linearization Methods ◽  
Reusable Launch Vehicle

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] A new guidance scheme for the terminal area energy management (TAEM) phase of an unpowered reusable launch vehicle (RLV) has been developed. The main advantage of the new guidance is the use of the quasi-equilibrium glide (QEG) condition to create a set of analytical functions for different glide-efficiency factors. Then, a coupling between the analytical solution and the ground-track prediction (GTP) is employed to create set of reference trajectories that guide the RLV from the current state to the desired state at approach and landing interface (ALI). The best feasible trajectory is selected by adjusting a geometrical parameters (heading alignment circle (HAC) position and HAC turn radius) based on the minimum residual range between the analytical and geometric ground-track predication methods. Unlike most trajectory planning algorithms, the proposed guidance scheme trajectory does not rely on numerical integration of the governing equations of motion, hence the geometrical parameters are obtained in a very short computational time. The QEG solution is used to create the longitudinal flight reference, while the lateral reference is defined by the GTP method. Standard linearization methods are used to design a closed-loop command in order to track the QEG profile. Furthermore, proportion (P) and proportion-derivative (PD) controls are used to modulate the bank angle during the vehicle flight. The glide efficiency factor is updated in order to make the predicted range satisfactory match the actual range-to-go. Off-nominal conditions, in terms of change in initial downtrack position, crosstrange, heading angle, altitude, flight-path angle, vehicle mass, vehicle drag and atmospheric density are tested using a Monte-Carlo simulation. The simulated results demonstrate the effectiveness of the proposed algorithm to guide the vehicle successfully under large dispersions of initial conditions.

scholarly journals Adaptive Entry Guidance for Hypersonic Gliding Vehicles Using Analytic Feedback Control

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Xunliang Yan ◽  
Peichen Wang ◽  
Shaokang Xu ◽  
Shumei Wang ◽  
Hao Jiang
Keyword(s):  
Feedback Control ◽  
Quasi Equilibrium ◽  
Dynamic Adjustment ◽  
Computationally Efficient ◽  
Bank Angle ◽  
Vehicle Data ◽  
Terminal Constraints ◽  
Flight Path Angle ◽  
And Performance ◽  
Almost All

This paper presents an adaptive, simple, and effective guidance approach for hypersonic entry vehicles with high lift-to-drag (L/D) ratios (e.g., hypersonic gliding vehicles). The core of the constrained guidance approach is a closed-form, easily obtained, and computationally efficient feedback control law that yields the analytic bank command based on the well-known quasi-equilibrium glide condition (QEGC). The magnitude of the bank angle command consists of two parts, i.e., the baseline part and the augmented part, which are calculated analytically and successively. The baseline command is derived from the analytic relation between the range-to-go and the velocity to guarantee the range requirement. Then, the bank angle is augmented with the predictive altitude-rate feedback compensations that are represented by an analytic set of flight path angle needed for the terminal constraints. The inequality path constraints in the velocity-altitude space are translated into the velocity-dependent bounds for the magnitude of the bank angle based on the QEGC. The sign of the bank command is also analytically determined using an automated bank-reversal logic based on the dynamic adjustment criteria. Finally, a feasible three-degree-of-freedom (3DOF) entry flight trajectory is simultaneously generated by integrating with the real-time updated command. Because no iterations and no or few off-line parameter adjustments are required using almost all analytic processing, the algorithm provides remarkable simplicity, rapidity, and adaptability. A considerable range of entry flights using the vehicle data of the CAV-H is tested. Simulation results demonstrate the effectiveness and performance of the presented approach.

scholarly journals Re-entry trajectory planning for a reusable launch vehicle

1999 ◽  
Author(s):  
Kenneth Mease ◽  
P. Teufel ◽  
H. Schoenenberger ◽  
D. Chen ◽  
S. Bharadwaj
Keyword(s):  
Trajectory Planning ◽  
Launch Vehicle ◽  
Reusable Launch Vehicle
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