smooth switching
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2022 ◽  
Vol 2022 ◽  
pp. 1-17
Author(s):  
Hoa Thi Truong ◽  
Xuan Bao Nguyen ◽  
Cuong Mai Bui

The magnetorheological elastomer (MRE) is a smart material widely used in recent vibration systems. A system using these materials often faces difficulties designing the controller such as unknown parameters, hysteresis state, and input constraints. First, a model is designed for the MRE-based absorber to portray the behavior of MRE and predict the appropriate electric current supplied. The conventional adaptive controller often suffers from so-called control singularities. The singularity-free adaptive controller is proposed to eliminate the singularity with parametric uncertainty. The proposed controller consists of four components: an adaptive linearizing controller, a deputy adaptive neural network controller, an auxiliary part designed for the controller to overcome the input constraint problem, and a smooth switching algorithm used to exchange the takeover rights of the two controllers. Moreover, the controller is designed to obtain the stabilization of hysteretic state estimation for the vibration system. The adaptive algorithms are proposed to update the unknown system parameters and to observe the unmeasurable hysteretic state. Meanwhile, closed-loop system stability is comprehensively assessed. Finally, the simulation performed on a quarter-car suspension with an MRE-based absorber shows the proposed controller's efficiency.


AIP Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 105103
Author(s):  
YuFeng Zhang ◽  
Zhe Feng ◽  
JunWei Jin ◽  
WenTao Gao ◽  
Hao Xu ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yiqi Xu

Purpose This paper aims to address the spacecraft attitude control problem using hybrid actuators in the presence of actuator saturation, uncertainties and faults, inertia uncertainties and external disturbances. Design/methodology/approach A hybrid actuator configuration is used where thrusters are engaged for rapid attitude maneuvers, while reaction wheels (RWs) are used for fine pointing. Findings The key advantages are two-fold: a finite-time high-level controller is designed to produce the three-axis virtual control torques; an online robust control allocation (RobCA) scheme is proposed to redistribute virtual control signals to the actuators with taking into account the actuator saturation, uncertainties and faults; and the RobCA scheme allows a smooth switch between thrusters and RWs, which handles the inaccuracy problem of thrusters and saturation problem of RWs. Practical implications An online RobCA algorithm is designed that maps the total control demands onto individual actuator settings and allows a smooth switch between thrusters and RWs. Simulation results show the effectiveness of the proposed control strategy. Originality/value This work may be used on modern space missions, which impose higher requirements on smooth switching of spacecraft thrusters and RWs.


2021 ◽  
Vol 252 ◽  
pp. 01019
Author(s):  
Kuo Tan ◽  
Hai Wu ◽  
Guo Hu ◽  
Qi Huang

DC distribution network consists of distributed generation, energy storage, load and AC distribution network, With the rapid development of DC distribution network and the increasing proportion of DC load, the operation mode of DC distribution network is more flexible. Different from the traditional AC distribution network, the traditional AC distribution network has a single operation mode, while the DC distribution network can operate in both parallel mode and island mode. Therefore, a control method suitable for different operation modes of DC distribution network is urgently needed. In this paper, a control method about loop closing and loop opening of DC distribution network is proposed. When receiving the command of loop closing or loop opening from the master station or local monitoring system, the loop closing control is judged by the switch state, fault state and operation state of converter. It solves the problem that the traditional AC distribution network control strategy is not applicable in DC distribution network, it realizes the smooth switching of DC distribution network closed loop operation and opened loop operation. This method has been used in the DC coordinated control device and successfully applied in the national key research and development plan of Suzhou active distribution network.


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