Development Trend and Stability Analysis of Creep Landslide With Obvious Slip Zone Under Rainfall-Taking Xinchang Xiashan Basalt Slope as an Example

The creep slope is a dynamic development process, from stable deformation to instability failure. For the slope with sliding zone, it generally creeps along the sliding zone. If the sliding zone controlling the slope sliding does not have obvious displacement, and the slope has unexpected instability without warning, the harm and potential safety hazard are often much greater than the visible creep. Studying the development trend of this kind of landslide is of great significance to slope treatment and landslide early warning. Taking Xiashan village landslide in Huishan Town, Xinchang County, Zhejiang Province as an example, the landslide point was determined by numerical simulation in 2006. Generally, the landslide is a typical long-term slow deformation towards the free direction. Based on a new round of investigation and monitoring, this paper shows that there are signs of creeping on the surface of the landslide since 2003, and there is no creep on the deep sliding surface. The joint fissures in the landslide area are relatively developed, and rainfall infiltration will soften the soft rock and soil layer and greatly reduce its stability. This paper collects and arranges the rainfall data of the landslide area in recent 30 years, constructs the slope finite element model considering rainfall conditions through ANSYS finite element software, and carries out numerical simulation stability analysis. The results show that if cracks appear below or above the slope’s sliding surface, or are artificially damaged, the sliding surface may develop into weak cracks. Then, the plastic zone of penetration is offset; In the case of heavy rain, the slope can unload itself under the action of rainfall. At this time, the slope was unstable and the landslide happened suddenly.

Active Vibration Control on a Smart Composite Structure using Modal-Shaped Sliding Mode Control

This paper proposes an active modal vibration control method based on a modal sliding mode controller applied to a smart material composite structure with integrated piezoelectric transducers as actuators and sensors. First, the electromechanical coupled system is identified using a modal reduced-order model. The sliding surface is based on the modal-filtered states and designed using a general formulation allowing the control of multiple vibration modes with multiple piezoelectric sensors and actuators. The performance and stability of the nonlinear controller are addressed and confirmed with the experimental results on a composite smart spoiler-shaped structure. The nonlinear switching control signal, based on the modal-shaped sliding surface improves the performances of the linear part of the control while maintaining not only stability but also robustness. The attenuation level achieved on the target modes on all piezoelectric sensors starts from -14dB up to -22dB, illustrating the strong potential of nonlinear switching control methods in active vibration control.

A novel non-singular terminal sliding mode control combined with integral sliding surface for perturbed quadrotor

In this article, a new dynamic non-singular terminal sliding mode control technique for a quadrotor system subjected to external disturbances is evaluated. The offered control approach is based on non-singular terminal sliding mode controller combined with proportional–integral–derivative sliding surface to improve the performance. The proposed controller is formulated using the Lyapunov theory which ensured the existence of the sliding mode surfaces in finite time. Furthermore, the chattering problem, caused by the switching position and attitude laws, has been reduced using the proposed controller. Moreover, a high-precision performance trajectory tracking can be obtained. The problem of the disturbances is addressed using the suggested controller. Simulation results show the feasibility and efficiency of the non-singular terminal sliding mode control-proportional–integral–derivative proposed approach.

Finite-time disturbance observer based-control of flexible spacecraft

This paper aims to design an attitude controller for a flexible spacecraft under external disturbance and uncertainty. The spacecraft’s attitude is controlled by a super twisting controller based on a disturbance observer. This paper’s spacecraft system is non-minimum phase since mode-shapes are included in the output; thus, the following four methods are designed to compensate for the constraint: (1) The output redefinition method, where outputs are redefined as a combination of mode-shapes and quaternions. (2) The flexible spacecraft is controlled without measuring the mode-shapes, and only the quaternion parameters are selected as the output. (3) An advanced sliding surface is proposed, in which the mode-shapes are considered in the sliding surface. (4) The difference between flexible and rigid spacecraft dynamics is considered as disturbance, and its effect on the system is compensated. The finite-time stability of the closed-loop system is proved by leveraging the Lyapunov theory. The numerical simulation illustrates the closed-loop system’s effectiveness in terms of robustness compared to the existing controller and the four mentioned methods.

DHMM-Based Asynchronous Finite-Time Sliding Mode Control for Markovian Jumping Lur’e Systems

This paper is concerned with the asynchronous problem for a class of Markovian jumping Lur’s system (MJLSs) via sliding mode control (SMC) in continuous-time domain. Specifically, the discrete hidden Markovian model (DHMM) is employed to describe the nonsynchronization between the controller modes and the MJLSs modes. In particular, considering the nonlinearity of MJLSs, a novel Lur’e-integral-type sliding surface is constructed. In order to ensure the finite-time stability of sliding mode dynamics and the accessibility of the specified sliding surface, the asynchronous Lur’e-type SMC law of the detector mode is presented. Finally, an example of DC motor is provided to demonstrate the effectiveness of the proposed technique.

Adaptive neural-based finite-time attitude synchronization and tracking control of multiple rigid bodies under actuator faults and saturation

Purpose The purpose of this paper, is to solve the problem of finite-time fault-tolerant attitude synchronization and tracking control of multiple rigid bodies in presence of model uncertainty, external disturbances, actuator faults and saturation. It is assumed that the rigid bodies in the formation may encounter loss of effectiveness and/or bias actuator faults. Design/methodology/approach For the purpose, adaptive terminal sliding mode control and neural network structure are used, and a new sliding surface is proposed to guarantee known finite-time convergence not only at the reaching phase but also on the sliding surface. The sliding surface is then modified using a proposed auxiliary system to maintain stability under actuator saturation. Findings Assuming that the communication topology between the rigid bodies is governed by an undirected connected graph and the upper bounds on the actuators’ faults, estimation error of model uncertainty and external disturbance are unknown, not only the attitudes of the rigid bodies in the formation are synchronized but also they track the time-varying attitude of a virtual leader. Using Lyapunov stability approach, finite-time stability of the proposed control algorithms demonstrated on the sliding phase as well as the reaching phase. The effectiveness of the proposed algorithm is also validated by simulation. Originality/value The proposed controller has the advantage that the need for any fault detection and diagnosis mechanism and the upper bounds information on estimation error and external disturbance is eliminated.