Distributed finite-time velocity-free attitude coordination control for spacecraft formations

2019

Summary This paper addresses the distributed observer‐based leader‐follower attitude consensus control problem for multiple rigid bodies. An intrinsic distributed observer is proposed for each follower to estimate the leader's trajectory, which is only available to a subset of followers. The proposed observer can guarantee that the estimated attitude evolves on rotation matrices all the time, and it provides us with a simple way to design the attitude consensus control law. The dynamics of rigid bodies and distributed observer are both modeled directly on rotation matrices, so that the singularity and ambiguity can be avoided. Furthermore, adopting the idea of disturbance observer on vector space, a gyro bias observer on the rotation matrices is proposed. Based on the distributed observer, three types of attitude consensus control law are proposed, which are respectively on the basis of full‐state, biased angular velocity, and external disturbance combined with biased angular velocity. Finally, the SimMechanics experiments are provided to illustrate effectiveness of the proposed theoretical results.

Section: Introductionmentioning

confidence: 99%

Distributed observer‐based leader‐follower attitude consensus control for multiple rigid bodies using rotation matrices

Peng

2019

“…Considering this, the homogeneous observer (HO) and finite‐time observer are widely designed to estimate the unknown state information. However, the HO can only realize the semiglobal finite‐time stability, and the convergence time cannot be estimated . The finite time observer in other works can only guarantee the observation errors converge to a region of zero in finite time, and the attitude derivatives instead of angular velocity were obtained in finite time.…”

Section: Introductionmentioning

confidence: 99%

Continuous robust fault‐tolerant control and vibration suppression for flexible spacecraft without angular velocity

Zong

Tian

et al. 2019

Summary The fault‐tolerant control and vibration suppression for flexible spacecraft without angular velocity measurement are investigated. External disturbances, actuator faults, unknown angular velocity, and flexible vibration are addressed simultaneously. Firstly, a model‐free adaptive supertwisting state observer and an angular velocity calculation algorithm in one step are developed by using attitude information only, which can estimate the angular velocity in finite time. Then, on the basis of angular velocity estimation, a novel continuous multivariable integral sliding mode (CMISM) is proposed for the first time, which is a combination of continuous nominal controller and a modified multivariable twisting controller to reject disturbances and faults. The CMISM can stabilize attitudes in finite time and attenuate chattering effectively. Furthermore, the input shaping technique is developed to achieve effective vibration suppression of the flexible appendages. Finally, the efficiency of the proposed method is illustrated by numerical simulations.

“…In three‐dimensional (3D) space, when considering a rigid body's translation and rotation simultaneously, its attitude control become a basic and also challenging work because the attitude is described by a nonlinear manifold and its kinematics is a nonlinear system . In the presence of modeling uncertainties, actuator faults, and disturbances, the finite‐time attitude control laws with terminal sliding mode have been proposed by Zhou et al The velocity‐free attitude synchronization with finite‐time convergence has been designed by Zou et al, and the finite‐time attitude synchronization of rigid bodies using Modified Rodrigues parameters (MRPs) attitude representation has been investigated by Meng et al and Du et al However, in the above mentioned literatures, their finite‐time intervals cannot be artificially adjusted but rely on some parameters and initial conditions of the system. Motivated by this observation, the fixed‐time stabilization is proposed by Polyakov to make the finite‐time interval be independent of initial state.…”

Section: Introductionmentioning

confidence: 99%

A specified‐time control framework for control‐affine systems and rigid bodies: A time‐rescaling approach

Peng

Sun

2019

Summary This paper addresses the specified‐time control problem for control‐affine systems and rigid bodies, wherein the specified‐time duration can be designed in advance according to the task requirements. By using the time‐rescaling approach, a novel framework to solve the specified‐time control problem is proposed, and the original systems are converted to the transformation systems based on which the specified‐time control laws for both control‐affine systems and rigid bodies are studied. Compared with the existing approaches, our proposed specified‐time control laws can be derived from the known stabilization control laws. To our best knowledge, it is the first time that transformation system–based specified‐time control framework for control‐affine system and rigid body dynamics is proposed. To further improve the convergence performance of specified‐time control, a finite‐time attitude synchronization control law for rigid bodies on rotation matrices is proposed, and thereby, the finite‐time–based specified‐time control law is designed eventually. In the end, numerical simulations and SimMechanics experiments are provided to illustrate effectiveness of the theoretical results.