Adaptive twisting sliding mode control for quadrotor unmanned aerial vehicles

© 2017 IEEE. This work addresses the problem of robust attitude control of quadcopters. First, the mathematical model of the quadcopter is derived considering factors such as nonlinearity, external disturbances, uncertain dynamics and strong coupling. An adaptive twisting sliding mode control algorithm is then developed with the objective of controlling the quadcopter to track desired attitudes under various conditions. For this, the twisting sliding mode control law is modified with a proposed gain adaptation scheme to improve the control transient and tracking performance. Extensive simulation studies and comparisons with experimental data have been carried out for a Solo quadcopter. The results show that the proposed control scheme can achieve strong robustness against disturbances while is adaptable to parametric variations

Adaptive sliding mode dynamic positioning control for a semi-submersible offshore platform

In this paper, an adaptive sliding mode dynamic positioning control approach is proposed for a semi-submersible offshore platform. The actuator dynamics are slow and thus a first order sliding mode control approach is used to maximise tracking accuracy in the presence of typically unmodelled actuator dynamics. The sliding mode control is designed with an adaptive feedback gain to counter the effects of model uncertainty and external disturbances such as the waves. The control implementation uses a sliding mode differentiator for online estimation of velocity and acceleration. The stability of the system is analyzed using Lyapunov methods. The control algorithm is validated using illustrative examples

Interdisciplinary design methodology for systems of mechatronic systems focus on highly dynamic environmental applications

This paper discusses a series of research challenges in the design of systems of mechatronic systems. A focus is given to environmental mechatronic applications within the chain “Renewable energy production - Smart grids - Electric vehicles”. For the considered mechatronic systems, the main design targets are formulated, the relations to state and parameter estimation, disturbance observation and rejection as well as control algorithms are highlighted. Finally, the study introduces an interdisciplinary design approach based on the intersectoral transfer of knowledge and collaborative experimental activities

EVENT-TRIGGERED SLIDING MODE CONTROL FOR CONSTRAINED NETWORKED CONTROL SYSTEMS

The paper describes a Non-linear Control (ETNC) approach for constrained Networked Feedback Control Systems (NFCS). The real-time controller execution is implemented based on the Event-triggering paradigm. A  nonlinear variable structure is used for the controller design. The nonlinear approach is based on the predefined sliding variable defined by the system states with a nonlinear switching function. The system's stability is analyzed regarding the evolution of the sliding variable. The Event-Triggered operation of the nonlinear controller is based on the prescribed triggering rule. The stability boundary of the sliding variable is subject to the preselected triggering condition, whose selection is a tradeoff of system performance, networks constraints and transmission capabilities. The main focus of the Event triggering approach is lowering network resources utilization in the steady-state behavior of the NFCS. The presented approach ensures a non-zero inter-event time of controller execution, which enables scheduling and optimization of the network operation regarding the network constraints and real-time system performance. The efficiency of the presented method is presented with a comparison of the classical time triggering approach.  The real measurement supports the results

Single phase second order sliding mode controller for complex interconnected systems with extended disturbances and unknown time-varying delays

Novel results on complex interconnected time-delay systems with single phase second order sliding mode control is investigated. First, a reaching phase in traditional sliding mode control (TSMC) is removed by using a novel single phase switching manifold function. Next, a novel reduced order sliding mode observer (ROSMO) with lower dimension is suggested to estimate the unmeasurable variables of the plant. Then, a new single phase second order sliding mode controller (SPSOSMC) is established based on ROSMO tool to drive the state variables into the specified switching manifold from beginning of the motion and reduce the chattering in control input. Then, a stability condition is suggested based on the well-known linear matrix inequality (LMI) method to ensure the asymptotical stability of the whole plant. Finally, an illustrated example is simulated to validate the feasible application of the suggested technique

High-precision XY stage motion control of industrial microscope

This paper presents an economic way to implement a high precision (um level) XY stage motion control for the industrial microscope using DC motors. Other than the prevailing design of using stepper motors where the stage is always locked under the motorized mode, the proposed design allows users to manually move the stage by introducing the friction engagement in between. The nonlinearity from the friction is then fully compensated by the sliding mode control (SMC) so that the stage can strictly follow the predefined motion profile. Possible chattering suppression methods are discussed and the accuracy loss is analyzed using LuGre friction model. Finetuning algorithm is then proposed to limit the position error within u2 um. Comparing to the other um-level industrial microscopes using stepper motors, the proposed solution achieves comparable performance with much lower costs