This paper proposes an anti-disturbance control scheme for the near space vehicle (NSV) based on terminal sliding mode (TSM) technique and disturbance observer method. To tackle the system uncertainty and the time-varying unknown external disturbance of the NSV, a disturbance observer based on TSM technique is designed which can render the disturbance estimate error convergent in finite time. Furthermore, an auxiliary design system is introduced to analyze the input saturation effect. Based on the developed disturbance observer and the auxiliary design system, an anti-disturbance attitude control scheme is developed for the NSV using the TSM technique to speed up the convergence of all signals in closed-loop system. For the closed-loop system, the stability is rigorously proved by using the Lyapunov method and we guarantee the finite time convergence of all closed-loop system signals in the presence of the integrated affection of the system uncertainty, the input saturation, and the unknown external disturbance. Simulation study results are given to show the effectiveness of the developed TSM anti-disturbance attitude control scheme using the disturbance observer and the auxiliary system for the NSV. CitationChen M, Ren B B, Wu Q X, et al. Anti-disturbance control of hypersonic flight vehicles with input saturation using disturbance observer.

The ever increasingly stringent performance requirements of modern mechanical systems have forced control engineers to look beyond traditional linear control theory for more advanced nonlinear controllers. During the past decade, a mathematically rigorous nonlinear adaptive robust control (ARC) theory has been developed and has been experimentally demonstrated achieving significant performance improvement in a number of motion control applications. This plenary paper first uses a simple motion control problem as an example to bring out the conceptual connection and nonlinear extension of the widely used PID controller structure to the developed ARC approach. Through this example, some of the key underlying working mechanisms of the ARC theory can be grasped easily. The paper then highlights how major issues in the precision motion control can be handled systematically and effectively with the ARC framework. The issues considered include (i) large variations of physical parameters of a system; (ii) unknown nonlinearities such as cogging and ripple forces of linear motors; (iii) dynamic uncertain nonlinearities with non-uniformly detectable unmeasured internal states (e.g., friction described by dynamic models in high precision motion controls); and (iv) control input saturation due to limited capacity of physical actuators. The precision motion control of a linear motor driven high-speed/high-acceleration industrial gantry is used as a case study and comparative experimental results are presented to illustrate the achievable performance and limitations of various ARC controllers in implementation.

SWIR dyes offer many advantages over their more common NIR congeners; however, the available options are limited. New SWIR imaging agents can be accessed by remodeling existing NIR molecules (i.e., hemicyanines (HDs)). In this study, we synthesized SWIR-HD, a modified HD featuring dimethylsilicon and benzo[cd]indolium groups that are designed to red-shift the absorbance and emission to 988 and 1126 nm, respectively. SWIR-HD was employed to visualize the liver and tumors via multimodal SWIR imaging.

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Nonholonomic wheeled mobile service robot’s posture error model denoted by polar coordinates in global coordinates is established .Based on the inherent discontinuousness of the closed-loop system model, a novel nonlinear state feedback stabilization control law is proposed，which causes closed-loop system state space equation of robot to have isolated equilibrium state at origin. By Lyapunov candidate function method，this paper concludes that the closed-loop system is global uniformly asymptotically stable at origin. Simulation results indicate that the proposed control law is effective.