High-energy orbit sliding mode control for nonlinear energy harvesting

Abstract Vibration energy harvesting has extensive application prospects in many significant occasions, such as mechanical structure health monitoring, vehicle tire pressure monitoring, IoT devices and human health monitoring. The nonlinearity is an effective method to improve the energy harvesting efficiency where there are low- and high-energy orbits in the multi-solution region of the system. The harvested power will be increased significantly when the system is guided from the low-energy orbit to the high-energy orbit. However, previous research mainly focuses on the theoretical and numerical investigation of controlling strategy, but the feasibility of control methods has not been verified experimentally. This paper proposes a high-energy sliding mode control method through rotatable magnets actuated by micro-motor. The electromechanical model of mono-stable and bi-stable systems with the identified nonlinear restoring force is established to design a sliding mode control algorithm for enhancing the energy harvesting performance. Simulation and experiment results demonstrate that the rotatable magnets with sliding mode control have a positive influence on reaching the high-energy orbit for both mono-stable and bi-stable systems within the multi-solution region. Moreover, the rotatable magnets method with a sliding mode control actuates the small magnets in the system for a short time with little consumption of energy. This research has provided a practical application of high-energy orbit control for improvement of the energy harvesting.

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Adaptive Backstepping Sliding Mode Control for Direct Driven Hydraulics

Proceedings ◽

10.3390/iecat2020-08496 ◽

2020 ◽

Vol 64 (1) ◽

pp. 1

Author(s):

Shuzhong Zhang ◽

Tianyi Chen ◽

Fuquan Dai

Keyword(s):

Sliding Mode Control ◽

Control Strategy ◽

Sliding Mode ◽

External Disturbance ◽

High Energy ◽

Hydraulic Actuator ◽

Adaptive Backstepping ◽

Mode Control ◽

Adaptive Law ◽

Backstepping Sliding Mode Control

Due to the advantages of high energy efficiency and environmental friendliness, the electro-hydraulic actuator (EHA) plays a vital role in fluid power control. One variant of EHA, double pump direct driven hydraulics (DDH), is proposed, which consists of double fixed-displacement pumps, a servo motor, an asymmetric cylinder and auxiliary components. This paper proposes an adaptive backstepping sliding mode control (ABSMC) strategy for DDH to eliminate the adverse effect produced by parametric uncertainty, nonlinear characteristics and the uncertain external disturbance. Based on theoretical analysis, the nonlinear system model is built and transformed. Furthermore, by defining the sliding manifold and selecting a proper Lyapunov function, the nesting problems (of the designed variable and adaptive law) caused by uncertain coefficients are solved. Moreover, the adaptive backstepping control and the sliding mode control are combined to boost system robustness. At the same time, the controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. Simulations of the DDH are performed with the proposed control strategy and proportional–integral–differential (PID), respectively. The results show that the proposed control strategy can achieve better position tracking and stronger robustness under parameter changing compared with PID.

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Hybrid Control of Offshore Jacket Platforms Using Decentralized Sliding Mode Control and Shape Memory Alloy-Rubber Bearing Under Multiple Hazards

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.4044361 ◽

2019 ◽

Vol 142 (1) ◽

Author(s):

Diptesh Das ◽

Minaruddin Khan

Keyword(s):

Shape Memory Alloy ◽

Sliding Mode Control ◽

Shape Memory ◽

Control Algorithm ◽

Hybrid Control ◽

Sliding Mode ◽

High Energy ◽

Multiple Hazards ◽

Mr Dampers ◽

Mode Control

Abstract The motivation and objective of the present study are to propose a hybrid control system for offshore jacket platforms to mitigate the vibrations induced by multiple hazards, namely, the earthquakes and regular and irregular waves. State-of-the-art indicates that not much work is reported on hybrid control of offshore jacket platforms for multiple hazards using a control algorithm, which is robust against uncertainties. A decentralized sliding mode control algorithm using magneto-rheological (MR) dampers is employed for the semi-active controller because of its robustness against parametric uncertainties and reliability. Passive shape memory alloy rubber bearings (SMARBs) are selected as passive isolators because of their high damping capacities, high fatigue resistance, and super elastic behavior, which are highly desirable for offshore applications. The scope of the present study is to demonstrate the efficiency of the proposed controller and investigate the effects of different influencing parameters. A jacket platform, reported in the literature, is taken as an illustrative example. A significant reduction in the top deck displacement is observed. The position and number of MR dampers affect the performance of the controller significantly. Limitations of the controller imposed due to the greater weightage or penalty imposed on displacements by the semi-active control algorithm as well as due to the magnetic saturation of MR dampers are overcome by the high energy dissipation of the passive SMARBs, thus making the hybrid controller highly efficient. The effectiveness of the controller is more for the earthquakes and random waves than for the regular waves.

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