scholarly journals Attitude and Vibration Control of Flexible Spacecraft Using Singular Perturbation Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Morteza Shahravi ◽  
Milad Azimi
Keyword(s):  
Singular Perturbation ◽  
Vibration Control ◽  
Time Scale ◽  
Attitude Control ◽  
Sliding Mode ◽  
Flexible Spacecraft ◽  
Perturbation Approach ◽  
Elastic Mode ◽  
Sliding Manifold ◽  
Slow Subsystem

This paper addresses a composite two-time-scale control system for simultaneous three-axis attitude maneuvering and elastic mode stabilization of flexible spacecraft. By choosing an appropriate time coordinates transformation system, the spacecraft dynamics can be divided into double time-scale subsystems using singular perturbation theory (SPT). Attitude and vibration control laws are successively designed by considering a time bandwidths separation between the oscillatory flexible parts motion describing a fast subsystem and rigid body attitude dynamics as a slow subsystem. A nonlinear quaternion feedback control, based on modified sliding mode (MSM), is chosen for attitude control design and a strain rate feedback (SRF) scheme is developed for suppression of vibrational modes. In the attitude control law, the modification to sliding manifold for slow subsystem ensures that the spacecraft follows the shortest possible path to the sliding manifold and highly reduces the switching action. Stability proof of the overall closed-loop system is given via Lyapunov analysis. The proposed design approach is demonstrated to combine excellent performance in the compensation of residual flexible vibrations for the fully nonlinear system under consideration, as well as computational simplicity.

Observer-based two-time scale robust control of free-flying flexible-joint space manipulators with external disturbances

Robotica ◽  
2017 ◽  
Vol 35 (11) ◽  
pp. 2201-2217 ◽  
Author(s):  
Xiaoyan Yu ◽  
Li Chen
Keyword(s):  
Robust Control ◽  
Singular Perturbation ◽  
Time Scale ◽  
Joint Space ◽  
Perturbation Approach ◽  
Linear Quadratic ◽  
Lagrange Equations ◽  
Flexible Joint ◽  
Space Manipulators ◽  
Slow Subsystem

SUMMARYObserver-based two-time scale robust control is proposed for free-flying flexible-joint space manipulators with unknown payload parameters and bounded disturbances. The dynamic equations of a free-flying space manipulator with two flexible revolute joints were derived by the momentum conservation law and the Lagrange equations. A flexibility compensator was introduced to make the equivalent joint stiffness large enough, which made traditional singular perturbation approach applicable. Then, a singular perturbation model was formulated and a reduced-order controller is proposed. This controller consisted of a slow sub-controller and a fast flexible-joint sub-controller. To the slow subsystem, a sliding observer based robust slow sub-controller was proposed. By optimal linear quadratic regulator method, the fast sub-controller was designed with the estimated velocity by linear observer. This fast sub-controller could stabilize the fast subsystem around the equilibrium trajectory created by the slow subsystem under the effect of the slow control. Finally the numerical simulations were carried out, which showed that elastic joint vibrations had been stabilized effectively and good tracking performances had been achieved.

scholarly journals HOSM Controller Using PI Sliding Manifold for an Integrated Active Control for Wheeled Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Antonio Navarrete Guzmán ◽  
Claudia Carolina Vaca García ◽  
Stefano Di Gennaro ◽  
Cuauhtémoc Acosta Lúa
Keyword(s):  
Attitude Control ◽  
Sliding Mode ◽  
Stability Theorem ◽  
Lateral Velocity ◽  
Ground Vehicle ◽  
Yaw Rate ◽  
Parameter Variations ◽  
Sliding Manifold ◽  
The Stability ◽  
Wheeled Vehicles

This study considers the design of a modified high-order sliding mode (HOSM) controller using a PI sliding surface to the attitude control of a ground vehicle. A robust-modified HOSM controller is derived, so that the lateral velocity and yaw rate tracks the desired trajectory despite the environment actions acting on the ground vehicle and parameter variations. The stability is guaranteed with Lyapunov’s stability theorem function. The performance of the dynamic controllers is evaluated using the CarSim simulator considering a challenging double steer maneuver.

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