Active shape adjustment of a cable-mesh reflector is a significant procedure to compensate the effects of a complicated space environment in orbit. In this paper, the active shape adjustment of a large cable-mesh reflector with actuators is addressed, and the dynamic input voltage profiles of actuators are estimated using a novel fast model predictive control method. The electromechanical coupling dynamic model of the cable-mesh reflector with piezoceramic (PZT) actuators is first established by using piezoelectric constitutive equations and Hamilton’s principle. For a certain shape distortion, the dynamic control voltage profiles are then obtained via the novel fast model predictive control method in which the structural dynamics model is reformulated as a novel explicit repression form to avoid the computations of matrix exponential. Additionally, some fast computation strategies based on the Newmark-$\beta$ method are used to increase computational efficiency. Finally, a 30-meter diameter cable-mesh reflector is chosen as a numerical example, and the simulation results demonstrate that the proposed control algorithm provides a valid and efficient solution for the shape control of large cable-mesh reflectors.

Subject to the limited envelope size and carrying capacity of a rocket, it could be one of the most promising solutions to construct a large space structure through multilaunching and on-orbit assembly. Taking the antenna of the solar power satellite as the research objective, a novel vibration suppression strategy is developed in this article to guarantee high structural stability of the large space structure during on-orbit assembly. The concept of distributed control unit, together with the varying location relationship matrices, reflects the structural characteristics of the large space structure during on-orbit assembly. The explicit expression form of the control unit’s dynamic model is first derived based on the Newmark-β method. Then, the distributed adaptive model predictive controller is proposed to suppress the vibration of the large space structure aroused by weak impact among assembling modules. Through recalculating the control matrices efficiently at each assembly, the proposed controller achieves adaptive updating along with the varying large space structure. The feasibility of the proposed distributed adaptive model predictive controller is investigated in the numerical simulations, and the centralized fast model predictive controller is adopted for better comparison. The results demonstrate that the distributed adaptive model predictive controller can effectively suppress vibration of the large space structure during on-orbit assembly, with good adaptability, robustness, and computation efficiency.

Robust finite-time control for spacecraft with coupled translation and attitude dynamics is investigated in the paper. An error-based spacecraft motion model in six-degree-of-freedom is firstly developed. Then a finite-time controller based on nonsingular terminal sliding mode control technique is proposed to achieve translation and attitude maneuvers in the presence of model uncertainties and environmental perturbations. A finite-time observer is designed and a modified controller is then proposed to deal with uncertainties and perturbations and alleviate chattering. Numerical simulations are finally provided to illustrate the performance of the proposed controllers.

In this paper, an adaptive law with an integral action is designed and implemented on a DC motor by employing a rotary encoder and tachometer sensors. The stability is proved by using the Lyapunov function. The tracking errors asymptotically converge to zero according to the Barbalat lemma. The tracking performance is specified by a reference model, the convergence rate of Lyapunov function is specified by the matrix Q and the control action and the state weighting are restricted by the matrix . The experimental results demonstrate the effectiveness of the proposed control. The maximum errors of the position and velocity with the integral action are reduced from 0.4 V and 1.5 V to 0.2 V and 0.4 V, respectively. The adaptive control with the integral action gives satisfactory performance, even when it suffers from input disturbance.