The article investigates the secure control against denial-of-service (DoS) attacks in sensor-controller channel and actuator fault for switched cyberphysical systems (CPSs). First, the concerned CPSs are subjected to the switching features and strict-feedback nonlinearities, and hence a compound switched system is exposited. Second, a switched state observer is formulated, while neural networks are introduced to identify the nonlinear functions and offset the actuator faults. Third, a switched controller is constructed based on the estimated output or measured output, depending on the DoS attack is active or sleeping. The resulted switched closed-loop system is proved to be input-to-state practically stable by the small-gain theorem, average dwell time, common Lyapunov function, and multiple Lyapunov function. Finally, numerical simulation validates the effectiveness of the suggested control.

Colonoscopy is an important procedure for the diagnosis of various pathologies, in particular cancer of the colon and of the rectum. However, colonoscopy is a procedure often painful for the patient and complex for the doctor. So in the biomedical field, a wireless microrobot in pipe that can move smoothly in water or aqueous medium has urgently been demanded. In this paper, we developed a new kind of wireless microrobot with symmetrical spiral structure, which also had symmetrical kinematic characteristics. According to the hydromechanical lubrication theory and Newton viscous law, we build the motion model of the microrobot, which will provide a theoretical basis on designing the optimal structure parameters of the microrobot. Through analysis, simulations and experiments, this paper had evaluated the effect of spiral angle, which could realize forward-backward, upward-downward motion and stopping at any position we need in the pipe. In addition, we obtained the moving speeds of forward-backward and upward-downward motion in the pipe. The experimental results indicated that the maximum moving speed is 36.5 mm/s at 14 Hz in the horizontal direction and 4.6 mm/s at 16Hz in the vertical direction with input currents of 0.7A. Finally, we designed a control panel for this system, which can control the microrobot current motion states intuitively and easily, and make our system more portable and compact. The developed wireless microrobot can move smoothly in water and other liquid medium and is very useful in the industrial.