Variable structure attitude control and elastic mode stabilization of flexible spacecraft

2003 ◽  
Author(s):  
A. Iyer ◽  
S.N. Singh
Keyword(s):  
Attitude Control ◽  
Variable Structure ◽  
Flexible Spacecraft ◽  
Elastic Mode ◽  
Mode Stabilization

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.

Sliding Mode Control and Elastic Mode Stabilization of a Robotic Arm With Flexible Links

1991 ◽  
Vol 113 (4) ◽  
pp. 669-676 ◽  
Author(s):  
P. J. Nathan ◽  
S. N. Singh
Keyword(s):  
Closed Loop ◽  
Joint Angle ◽  
Sliding Mode ◽  
Variable Structure ◽  
Terminal State ◽  
Loop System ◽  
Robotic Arm ◽  
Closed Loop System ◽  
Elastic Mode ◽  
Mode Stabilization

This paper treats the question of control of an elastic robotic arm of two links based on variable structure system (VSS) theory and pole assignment technique for stabilization. A discontinuous joint angle control law, based on VSS theory, is designed which accomplishes asymptotic decoupled joint angle trajectory tracking. In the closed-loop system, the trajectories are attracted toward a chosen hypersurface in the state space and then slide along it. Although, joint angles are controlled using variable structure control (VSC) law, the flexible modes of the links are excited. Using center manifold theory, it is shown that the closed-loop system, including the sliding mode controller, is stable. Based on a linearized model about the terminal state, a stabilizer is designed using pole assignment technique to control the elastic oscillations of the links. A control logic is included which switches the stabilizer at the instant when the joint angle trajectory enters a specified neighborhood of the terminal state. Simulation results are presented to show that in the closed-loop system, accurate joint angle trajectory tracking, and elastic mode stabilization are accomplished in the presence of payload uncertainty.

Active Control Comparison of Vibration in Flexible Spacecraft Using Different Active Friction Joints

2013 ◽  
Vol 446-447 ◽  
pp. 1160-1164
Author(s):  
Sahar Bakhtiari Mojaz ◽  
Hamed Kashani
Keyword(s):  
Energy Dissipation ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Excitation Amplitude ◽  
Step Function ◽  
Flexible Spacecraft ◽  
Control Effort ◽  
Stick Slip ◽  
Control Comparison ◽  
Frictional Joints

Vibration properties of most assembled mechanical systems depend on frictional damping in joints. The nonlinear transfer behavior of the frictional interfaces often provides the dominant damping mechanism in structure and plays an important role in the vibratory response of it. For improving the performance of systems, many studies have been carried out to predict measure and enhance the energy dissipation of friction. This paper presents a new approach to vibration reduction of flexible spacecraft with enhancing the energy dissipation of frictional dampers. Spacecraft is modeled as a 3 degree of freedom mass-spring system which is controlled by a lead compensator and System responses to step function evaluated. Coulomb and Jenkins element has been used as vibration suppression mechanisms in joints and sensitivity of their performance to variations of spacecraft excitation amplitude and damper properties is analyzed. The relation between frictional force and displacement derived and used in optimization of control performance. Responses of system and control effort needed for the vibration control are compared for these two frictional joints. It is shown that attitude control effort reduces, significantly with coulomb dampers and response of system improves. On the other hand, due to stick-slip phenomena in Jenkins element, we couldn’t expect the same performance from Jenkins damper.

scholarly journals Dynamic Sliding Mode Controller with Variable Structure for Fast Satellite Attitude Maneuver

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Gao Shan ◽  
Li You ◽  
Xue Huifeng ◽  
Yao ShuYue
Keyword(s):  
Convergence Rate ◽  
Attitude Control ◽  
Sliding Mode ◽  
Variable Structure ◽  
System Stability ◽  
System State ◽  
Satellite Attitude ◽  
Satellite Attitude Control ◽  
Attitude Maneuver ◽  
Mode Parameter

In order to deal with the low convergence rate of the standard sliding mode in satellite attitude control, a novel variable structure sliding mode is constructed in this paper by designing the update law of the sliding mode parameter. By implementing this method, the advantage such as simple structure and strong robustness of the standard sliding mode are maintained and the system convergence rate is largely improved. The fixed sliding mode parameter is modified, and the update law is designed. When the system state is away from the sliding mode surface, the parameter is fixed, and when the system state approaches the sliding mode surface, the parameter begins to update. The constraint on control torque and angular velocity is taken into consideration, and the constraint on control parameters is given to ensure that the system state do not exceed its upper bound. System stability is proved by the Lyapunov stability theorem, and the superiority of the proposed controller is demonstrated by numerical simulation.

Sign in / Sign up

Export Citation Format

Share Document