scholarly journals Robust Trajectory Planning for Hypersonic Glide Vehicle with Parametric Uncertainties

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Chunyun Dong ◽  
Zhi Guo ◽  
Xiaolong Chen
Keyword(s):  
Optimal Control ◽  
Trajectory Optimization ◽  
Fitness Function ◽  
Uncertainty Propagation ◽  
Control Law ◽  
Outer Loop ◽  
Loop Optimization ◽  
Robust Optimal Control ◽  
Decision Variables ◽  
Time Optimal

A hybrid double-loop optimization algorithm combing particle swarm optimization (PSO) and nonintrusive polynomial chaos (NIPC) is proposed for solving the robust trajectory optimization of hypersonic glide vehicle (HGV) under uncertainties. In the outer loop, the PSO method searches globally for the robust optimal control law according to a penalized fitness function that contains the system robustness considerations. In the inner loop, uncertainty propagation of the stochastic system is performed using the NIPC method, to provide statistical moments for the iterative scheme of the PSO method in the outer loop. Only control variables are discretized, and the state constraints are satisfied implicitly through the numerical integration process, which reduces the number of decision variables as well as the huge amount of computation increased by NIPC. In the end, the robust optimal control law is achieved conveniently. Numerical simulations are carried out considering a classical time-optimal trajectory optimization problem of HGV with uncertainties in both initial states and aerodynamic coefficients. The results demonstrate the feasibility and effectiveness of the proposed method.

Simple anti-swing feedback control for a gantry crane

Robotica ◽  
2003 ◽  
Vol 21 (6) ◽  
pp. 655-666 ◽  
Author(s):  
Yannick Aoustin ◽  
Alexander Formal'sky
Keyword(s):  
Optimal Control ◽  
Piecewise Linear ◽  
Continuous Functions ◽  
Time Optimal Control ◽  
Gantry Crane ◽  
Control Law ◽  
Reference Trajectory ◽  
Controlling Parameter ◽  
Input Signals ◽  
Time Optimal

We propose a simple quasi time optimal control law for a gantry crane with a payload. The force applied to the trolley is a controlling parameter. The control law consists of two parts: a feedforward term and a trolley position and velocity feedback term.Initially, we synthesize the feedforward term and the corresponding reference trajectory by computing the time optimal control for the system mass center. The computed optimal control is a discontinuous function of time with several switching time instants. Undesirable large vibrations due to the payload sway appear under this control. Therefore, we transform this control, replacing its jumps by the piecewise linear continuous functions. The computed feedforward term and the reference trajectory are used as input signals of the PD-controller.

Smooth time-optimal attitude control of spacecraft

2018 ◽  
Vol 233 (7) ◽  
pp. 2331-2343 ◽  
Author(s):  
Yabo Hu ◽  
Baolin Wu ◽  
Yunhai Geng ◽  
Yunhua Wu
Keyword(s):  
Attitude Control ◽  
Trajectory Optimization ◽  
Angular Acceleration ◽  
Optimization Method ◽  
Frequency Domain Analysis ◽  
Flexible Spacecraft ◽  
Control Law ◽  
Control Torque ◽  
Attitude Maneuver ◽  
Time Optimal

In this paper, a trajectory optimization method for generating smooth and approximate time-optimal attitude maneuver trajectories of flexible spacecraft is proposed. Smooth attitude maneuver is highly desirable for flexible spacecraft, since vibration of flexible appendices can be suppressed. In order to obtain smooth and approximate time-optimal attitude trajectory, a novel objective function composed of two terms is developed in the problem of trajectory optimization: the first term is proportional to the total maneuver time and the other one is proportional to the integral of the squared control torque derivatives. This latter term ensures that the generated trajectory is smooth. The degree of the smoothness of the trajectory can be adjusted by the weights of these two terms. The constraints on angular velocity and angular acceleration are considered in the proposed method. A closed-loop tracking control law is then employed to track the optimized reference attitude trajectory. Numerical simulations and frequency domain analysis show that the proposed method can generate smoother trajectory than traditional time-optimal methods, which leads to less vibration during attitude maneuver of a flexible spacecraft.

Trajectory Control of Miniature Helicopters Using a Unified Nonlinear Optimal Control Technique

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Ming Xin ◽  
Yunjun Xu ◽  
Ricky Hopkins
Keyword(s):  
Optimal Control ◽  
Real Time ◽  
Control Method ◽  
Nonlinear Optimal Control ◽  
Suboptimal Control ◽  
Control Technique ◽  
Control Law ◽  
Wind Gust ◽  
Flight Envelope ◽  
Time Optimal

It is always a challenge to design a real-time optimal full flight envelope controller for a miniature helicopter due to the nonlinear, underactuated, uncertain, and highly coupled nature of its dynamics. This paper integrates the control of translational, rotational, and flapping motions of a simulated miniature aerobatic helicopter in one unified optimal control framework. In particular, a recently developed real-time nonlinear optimal control method, called the θ-D technique, is employed to solve the resultant challenging problem considering the full nonlinear dynamics without gain scheduling techniques and timescale separations. The uniqueness of the θ-D method is its ability to obtain an approximate analytical solution to the Hamilton–Jacobi–Bellman equation, which leads to a closed-form suboptimal control law. As a result, it can provide a great advantage in real-time implementation without a high computational load. Two complex trajectory tracking scenarios are used to evaluate the control capabilities of the proposed method in full flight envelope. Realistic uncertainties in modeling parameters and the wind gust condition are included in the simulation for the purpose of demonstrating the robustness of the proposed control law.

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