A time suboptimal method for real-time spacecraft attitude agile maneuvering with angular velocity constraint

2017 ◽  
Vol 233 (2) ◽  
pp. 561-572 ◽  
Author(s):  
Yun-Hua Wu ◽  
Ya-Bo Hu ◽  
Bing Hua ◽  
Zhi-Ming Chen ◽  
Lin-Lin Ge
Keyword(s):  
Angular Velocity ◽  
Real Time ◽  
Attitude Control ◽  
Pseudospectral Method ◽  
Suboptimal Control ◽  
Spacecraft Attitude ◽  
Attitude Maneuver ◽  
Time Optimal ◽  
Real Time Application ◽  
Velocity Constraint

A time suboptimal method for on-orbit rapid attitude maneuver control of agile spacecraft with attitude angular velocity constraint is proposed, which can generate suboptimal control torque command for real-time application. Spacecraft time-optimal slew maneuver has been studied by many researchers, and most of the interest is focused on formulating and resolving the optimization problem of spacecraft attitude maneuver in proper ways. Pseudospectral method, among most of the existing methods, is feasible to figure out the preferred solution satisfying the control precision, which possesses the values of practical application. However, pseudospectral method consumes much time for planning attitude trajectory making it impossible for on-orbit spacecraft real-time control, especially for observation mission with frequent maneuver. After thorough analysis of the time optimal attitude maneuvering results, several patterns with respect to the generation of attitude control command are summarized that result in an interpolation control method, which is time suboptimal and is capable of on-orbit real-time application for spacecraft with small products of inertia. Closed-loop control is implemented to cancel the final pointing error. Several simulations have been performed to validate the performance of the proposed strategy, and have demonstrated the potential application for small agile spacecraft with limited attitude control ability.

Altitude Controller Design for Quadcopter UAV

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Muhammad Zaki Mustapa
Keyword(s):  
Real Time ◽  
Attitude Control ◽  
Controller Design ◽  
Design Method ◽  
Time Windows ◽  
The Real ◽  
Data Acquisition Card ◽  
Aerial Vehicle ◽  
Hovering Control ◽  
Real Time Application

This paper discusses on attitude control of a quadcopter unmanned aerial vehicle (UAV) in real time application. Newton-Euler equation is used to derive the model of system and the model characteristic is analyzed. The paper describes the controller design method for the hovering control of UAV automatic vertical take-off system. In order to take-off the quadcopter and stable the altitude, PID controller has been designed. The scope of study is to develop an altitude controller of the vertical take-off as realistic as possible. The quadcopter flight system has nonlinear characteristics. A simulation is conducted to test and analyze the control performance of the quadcopter model. The simulation was conducted by using Mat-lab Simulink. On the other hand, for the real time application, the PCI-1711 data acquisition card is used as an interface for controller design which routes from Simulink to hardware. This study showed the controller designs are implemented and tuned to the real system using Real Time Windows Target approach by Mat-Lab Simulink.

Pseudospectral Real-Time Optimal Energy Control with Safety Constraints for Heavy-Haul Trains

2017 ◽  
Vol 21 (2) ◽  
pp. 258-265
Author(s):  
Rui Zhang ◽  
◽  
Jun Peng ◽  
Bin Chen ◽  
Hongtao Liao ◽  
...  
Keyword(s):  
Optimal Control ◽  
Real Time ◽  
Closed Loop ◽  
Pseudospectral Method ◽  
Heavy Haul Train ◽  
Heavy Haul ◽  
Time Optimal ◽  
Safety Constraints ◽  
Heavy Haul Trains ◽  
Control Principle

Heavy-haul trains must be energy-efficient and safe during their operations. Owing to the multidimensional high-order nonlinear characteristic of heavy-haul trains, which include numerous cars, this paper proposes a uniform pseudospectral real-time closed-loop optimal control framework to minimize the energy consumption with control inputs and state constraints based on the Radau Pseudospectral Method (RPM). In the framework, in order to ensure safe running of the heavy-haul train, the desired in-train force and speed limit requirements are formulated as constraints of optimal control. Simultaneously, a constrained closed-loop optimal control is constructed by using the receding horizon control principle and pseudospectral observer, in which RPM is leveraged to obtain real-time optimal solutions. The effectiveness of the proposed approach is verified from simulation results.

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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