scholarly journals Adaptive Damping Variable Sliding Mode Control for an Electrohydrostatic Actuator

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 83
Author(s):  
Linjie Li ◽  
Mingkang Wang ◽  
Rongrong Yang ◽  
Yongling Fu ◽  
Deming Zhu
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Hydraulic System ◽  
Sliding Mode ◽  
Parametric Uncertainties ◽  
Tracking Accuracy ◽  
Mode Control ◽  
Tracking Tasks ◽  
Variable Damping ◽  
Adaptive Control Law

An electrohydrostatic actuator (EHA) is a basic mechanical/hydraulic system with deficiencies including significant nonlinearity and parametric uncertainties. In line with the challenges of designing a high-precision control strategy, an adaptive damping variable sliding mode controller is established, which extends our previous work on EHA control. The proposed controller integrates variable-damping sliding mode control, parametric adaptation, and an extended state observer. The parametric uncertainties are effectively captured and compensated by employing an adaptive control law, while system uncertainties are reduced, and disturbances are estimated and compensated with a fast and stable response. We evaluated the proposed control strategy on a variety of position tracking tasks. The experimental results demonstrate that our controller significantly outperforms the widely used methods in overshoot suppression, settling time, and tracking accuracy.

scholarly journals Fractional-Order Iterative Sliding Mode Control Based on the Neural Network for Manipulator

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xin Zhang ◽  
Wenbo Xu ◽  
Wenru Lu
Keyword(s):  
Neural Network ◽  
Sliding Mode Control ◽  
Fractional Order ◽  
Control Strategy ◽  
Sliding Mode ◽  
Rbf Neural Network ◽  
Tracking Error ◽  
Position Tracking ◽  
Tracking Accuracy ◽  
Mode Control

This study aimed to improve the position tracking accuracy of the single joint of the manipulator when the manipulator model information is uncertain. The study is based on the theory of fractional calculus, radial basis function (RBF) neural network control, and iterative sliding mode control, and the RBF neural network fractional-order iterative sliding mode control strategy is proposed. First, the stability analysis of the proposed control strategy is carried out through the Lyapunov function. Second, taking the two-joint manipulator as an example, simulation comparison and analysis are carried out with iterative sliding mode control strategy, fractional-order iterative sliding mode reaching law control strategy, and fractional-order iterative sliding mode surface control strategy. Finally, through simulation experiments, the results show that the RBF neural network fractional-order iterative sliding mode control strategy can effectively improve the joints’ tracking and control accuracy, reduce the position tracking error, and effectively suppress the chattering caused by the sliding mode control. It is proved that the proposed control strategy can ensure high-precision position tracking when the information of the manipulator model is uncertain.

scholarly journals Adaptive Super Twisting Sliding Mode Control With Fractional Order Sliding Surface for Trajectory Tracking of a Mobile Robot

2021 ◽  
Author(s):  
Huanhuan Ren ◽  
Lizhong Zhang ◽  
Chengzhi Su
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Control Strategy ◽  
Sliding Mode ◽  
Position Tracking ◽  
Sliding Surface ◽  
Tracking Accuracy ◽  
External Interference ◽  
Reaching Law ◽  
Mode Control

Abstract This paper presents the position tracking performance of the robot system with uncertainties and external disturbances by using super twisting sliding mode control (STSMC) with fractional order (FO) sliding surface. In this scheme, fractional calculus theory is applied to the design of the sliding surface of STSMC, which can reduce the chattering caused by the switch control action and ensure that the control system has strong robust characteristics and fast convergence. Based on Lyapunov stability theory, the controller ensures the existence of sliding mode of sliding surface in finite time. Moreover, an adaptive STSMC reaching law is adopted. By using the fractional order nonlinear switching manifold and adaptive reaching law, the control performance can be obtained more effectively in sliding mode phase and the reaching phase, respectively. Finally, in order to validate the effectiveness and robustness of the proposed control strategy, the linear PID control strategy and the classical STSMC strategy are designed for comparative analysis, and the numerical calculation is carried out according to the dynamic model to study the position tracking accuracy of the robot under uncertainty and external interference.

scholarly journals Time-Varying Integral Adaptive Sliding Mode Control for the Large Erecting System

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xie Zheng ◽  
Xie Jian ◽  
Du Wenzheng ◽  
Li Liang ◽  
Guo Yang
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Time Varying ◽  
Tracking Accuracy ◽  
Mode Control ◽  
Global Robustness ◽  
System Uncertainties ◽  
Integral Sliding Surface

Considering the nonlinearities, uncertainties of large erecting system, and the circumstance disturbances in erecting process, a novel sliding mode control strategy is proposed in this research. The proposed control strategy establishes the sliding mode without reaching phase using an integral sliding surface. Thus, robustness against uncertainties increases from the very beginning of the process. Furthermore, adaptive laws are used for the controller to estimate the unknown but bounded system uncertainties. Therefore, the upper bounds of the system uncertainties are not required to be known in advance. Then, the time-varying term is applied to ensure the global robustness. Moreover, the boundary layer method is used to attenuate the high frequency chattering. The experiment results demonstrated that the proposed strategy could effectively restrain parametric uncertainties and external disturbances and improve the tracking accuracy in the erecting process. In addition, the control performance of the proposed control strategy is better than that of the PID control and the conventional sliding mode control.

scholarly journals Influence of Control Strategy in Risk Mitigation of Building Damage Due to Earthquake

2021 ◽  
Author(s):  
Normaisharah Mamat ◽  
Mohd Fauzi Othman ◽  
Mohd Fitri Mohd Yakub
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Structural Integrity ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Building Structures ◽  
Sliding Surface ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Nonsingular Terminal Sliding Mode

Abstract Building structures are prone to damage due to natural disasters, and this challenges structural engineers to design safer and more robust building structures. This study is conducted to prevent these consequences by implementing a control strategy that can enhance a building's stability and reduce the risk of damage. Therefore, to realize the structural integrity of a building, a hybrid control device is equipped with control strategies to enhance robustness. The control strategy proposed in this study is adaptive nonsingular terminal sliding mode control (ANTSMC). ANTSMC is an integrated controller of radial basis function neural network (RBFNN) and nonsingular terminal sliding mode control (NTSMC), which has a fast dynamic response, finite-time convergence, and the ability to enhance the control performance against a considerable uncertainty. The proposed controller is designed based on the sliding surface and the control law. The building with a two-degree-of-freedom (DOF) system is designed in Matlab/Simulink and validated with the experimental work connected to the LMSTest.Lab software. The performance of this controller is compared with those of the terminal sliding mode control (TSMC) and NTSMC in terms of the displacement response, sliding surface, and the probability of damage. The result showed that the proposed controller, ANTSMC can suppress vibrations up to 46%, and its percentage probability of complete damage is 15% from the uncontrolled structure. Thus, these findings are imperative towards increasing the safety level in building structures and occupants, and reducing damage costs in the event of a disaster.

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