Lunar soft landing rapid trajectory optimization using direct collocation method and nonlinear programming

2007 ◽  
Author(s):  
Lianghui Tu ◽  
Jianping Yuan ◽  
Jianjun Luo ◽  
Xin Ning ◽  
Ruiwu Zhou
Keyword(s):  
Nonlinear Programming ◽  
Collocation Method ◽  
Trajectory Optimization ◽  
Soft Landing ◽  
Direct Collocation ◽  
Direct Collocation Method

Trajectory Optimization for Spacecraft Proximity Rendezvous Using Direct Collocation Method

2012 ◽  
Vol 433-440 ◽  
pp. 6652-6656 ◽  
Author(s):  
Tao Liu ◽  
Yu Shan Zhao ◽  
Peng Shi ◽  
Bao Jun Li
Keyword(s):  
Nonlinear Programming ◽  
Control Problem ◽  
Programming Problem ◽  
Collocation Method ◽  
Trajectory Optimization ◽  
Collocation Methods ◽  
Nonlinear Programming Problem ◽  
Reference Orbit ◽  
Direct Collocation ◽  
Direct Collocation Method

Trajectory optimization problem for spacecraft proximity rendezvous with path constraints was discussed using direct collocation method. Firstly, the model of spacecraft proximity rendezvous in elliptic orbit optimization control problem was presented, with the dynamic equations established in the target local orbital frame, and the performance index was minimizing the total fuel consumption. After that the optimal control problem was transcribed into a large scale problem of Nonlinear Programming Problem (NLP) by means of Hermite-Simpson discretization, which was one of the direct collocation methods. Then the nonlinear programming problem was solved using MATLAB software package SNOPT. Finally, to verify this method, the fuel-optimal trajectory for finite thrust was planned for proximity rendezvous with elliptic reference orbit. Numerical simulation results demonstrate that the proposed method was feasible, and was not sensitive to the initial condition, having good robustness.

scholarly journals Trajectory Optimization for a Cruising Unmanned Aerial Vehicle Attacking a Target at Back Slope While Subjected to a Wind Gradient

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Tieying Jiang ◽  
Jie Li ◽  
Bing Li ◽  
Kewei Huang ◽  
Chengwei Yang ◽  
...  
Keyword(s):  
Collocation Method ◽  
Unmanned Aerial Vehicle ◽  
Trajectory Optimization ◽  
Time Function ◽  
Full Account ◽  
Direct Collocation ◽  
Motion Features ◽  
Aerial Vehicle ◽  
Direct Collocation Method ◽  
Motion Characteristics

The trajectory of a tubular launched cruising unmanned aerial vehicle is optimized using the modified direct collocation method for attacking a target at back slope under a wind gradient. A mathematical model of the cruising unmanned aerial vehicle is established based on its operational and motion features under a wind gradient to optimize the trajectory. The motion characteristics of  “altitude adjustment” and “suicide attack” are taken into full account under the combat circumstance of back slope time key targets. By introducing a discrete time function, the trajectory optimization is converted into a nonlinear programming problem and the SNPOT software is applied to solve for the optimal trajectory of the missile under different wind loads. The simulation results show that, for optimized trajectories, the average attack time decreased by up to 29.1% and the energy consumption is reduced by up to 25.9% under specified wind gradient conditions.A,ωdire, andWmaxhave an influence on the flight trajectories of cruising unmanned aerial vehicle. This verifies that the application of modified direct collocation method is reasonable and feasible in an effort to achieve more efficient missile trajectories.

Study of the Optimal Design for the Gliding Trajectory

2014 ◽  
Vol 568-570 ◽  
pp. 1063-1067
Author(s):  
Jian Jun Wang ◽  
Jian Qiao Yu
Keyword(s):  
Optimal Design ◽  
Trajectory Optimization ◽  
Shooting Method ◽  
Particle Trajectory ◽  
Longitudinal Plane ◽  
Direct Collocation ◽  
Direct Collocation Method ◽  
Direct Shooting ◽  
Particle Trajectory Model ◽  
Drag Ratio

The optimal design for the gliding trajectory is studied. The particle trajectory model in the longitudinal plane is established. Aiming at solving the problems in numerical solution ,the direct shooting method based on the interpolating function of Akima is put forward .In direct collocation method, the parameters of the trajectory with approximate maximum lift-drag ratio is adopted as the starting value of the optimal variables. The trajectory with approximate maximum lift-drag ratio could be obtained by the search method. The transfer approach of turning the problem of trajectory optimization to the problem of parameter optimization by the direct shooting method is illustrated. To one kind of guided vehicles in simulation, the simulation results prove the practicability of the direct shooting method.

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