Finite‐time attitude control for rigid spacecraft‐based on adaptive super‐twisting algorithm

Abstract

This study addresses the finite-time attitude tracking control for rigid spacecraft with external disturbances and inertia uncertainties. A novel adaptive-gain super-twist algorithm (STA) improves the control performance of standard STA, and the dynamically adapted control gains can resolve non-overestimating problem. The presented controllers do not require any knowledge on inertial uncertainties and external disturbances, and are anti-chattering and anti-singularity. The closedloop spacecraft system under the proposed controllers can provide rapidity, robustness, accuracy and anti-wasting energy simultaneously, which is largely ignored in the existing literatures. The finite-time rigorous convergence, an estimation of the convergence time and accurate expression of convergence region are also provided. Finally, comparison results demonstrate that the presented controllers can achieve higher control performance than existing methods. Furthermore, digital simulations utilising the physical parameters of Uosat-12 verify the effectiveness of the proposed controllers.

Adaptive fuzzy finite-time control for spacecraft formation with communication delays and changing topologies

“…Though as the analysis in [17] and [19], the surface has a high convergence rate either near the equilibrium or far away from it, since its derivative contains e γ2−1ė , which may cause singularity due tȯ e = 0, e = 0. In order to solve this problem, numbers of methods were developed in [23][24][25]. They all find a region Ω, where the singularity problem will be avoided.…”

“…Then a continuous finite-time control scheme using a new form of TSM for rigid robotic manipulators was proposed in [19], which has faster and high-precision in both the reaching and sliding phase compared with the controllers in [16][17][18] . Motivated by the work of [19], many modified TSMs have been applied successfully in spacecraft control [20][21][22][23][24][25]. In comparison with the modified methods in [22][23][24][25] to avoid singularity, the recently developed nonsingular fast terminal sliding mode control (NFTSMC) method in [26], promises fast convergence speed.…”

“…Motivated by the work of [19], many modified TSMs have been applied successfully in spacecraft control [20][21][22][23][24][25]. In comparison with the modified methods in [22][23][24][25] to avoid singularity, the recently developed nonsingular fast terminal sliding mode control (NFTSMC) method in [26], promises fast convergence speed.…”

Decentralized control for harmonic drive–based modular and reconfigurable robots with uncertain environment contact

“…Second, design the control law u i2 to compensate the model uncertain terms in _ s i . In order to provide a description of the model uncertainties supported by the ASTA, according to equation (23) and the categories of model uncertainties, one can reformulate model uncertainties as…”

“…First, by employing a control-oriented harmonic drive model that considers the compliance of both the wave generator and flexspline, the dynamic model of the MRR is formulated as a synthesis of interconnected subsystems, in which the magnitudes of the interconnected couplings between the joints are decreased significantly. Second, based on the integral sliding mode control (ISMC) technique 21,22 and the adaptive super-twisting algorithm (ASTA), 23,24 a decentralized controller is proposed which utilizes only encoder data of each isolate joint module to compensate model uncertainty and to reduce the chattering effect of the controller, as well as the stability of the closed-loop MRR system is proved using Lyapunov theory. Finally, simulations are conducted for 2-degreeof-freedom (DOF) MRRs with different configurations under the situations of dynamic contact and collision to investigate the advantage of the proposed approach.…”