Active fault-tolerant control of a Schon̈flies parallel manipulator based on time delay estimation

Robotica ◽  
2021 ◽  
pp. 1-18
Author(s):  
Pegah Ghaf-Ghanbari ◽  
Mahmood Mazare ◽  
Mostafa Taghizadeh

Abstract In this paper, a new hybrid fault-tolerant control (FTC) strategy based on nonsingular fast integral-type terminal sliding mode (NFITSM) and time delay estimation (TDE) is proposed for a Schönflies parallel manipulator. In order to detect, isolate, and accommodate actuator faults, TDE is used as an online fault estimation algorithm. Stability analysis of the closed-loop system is performed using Lyapunov theory. The proposed controller performance is compared with conventional sliding mode and feedback linearization control methods. The obtained results reveal the superiority of the proposed FTC based on TDE and NFITSM.

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2424
Author(s):  
Yong Yang ◽  
Yunbing Yan ◽  
Xiaowei Xu

It is difficult to model and determine the parameters of the steer-by-wire (SBW) system accurately, and the perturbation is variable with complex and changeable tire–road conditions. In order to improve the control performance of the vehicle SBW system, an adaptive fast super-twisting sliding mode control (AFST-SMC) scheme with time-delay estimation (TDE) is proposed. The proposed scheme uses TDE to acquire the lumped dynamics in a simple way and establishes a practical model-free structure. Then, a fractional order (FO) sliding mode surface and a fast super-twisting sliding mode control structure were designed on the basic super-twisting sliding mode to ensure fast convergence and high control accuracy. Since the uncertain boundary information of the actual system is unknown, a novel adaptive algorithm is proposed to regulate the control gain based on the control errors. Theoretical analysis concerning system stability is given based on the Lyapunov theory. Finally, the effectiveness of the method is verified through comparative experiments. The results show that the proposed TDE-AFST-FOSMC control scheme has the advantages of model-free, fast response and high accuracy.


2019 ◽  
Vol 9 (19) ◽  
pp. 4010 ◽  
Author(s):  
Ngoc Phi Nguyen ◽  
Sung Kyung Hong

Fault-tolerant control is becoming an interesting topic because of its reliability and safety. This paper reports an active fault-tolerant control method for a quadcopter unmanned aerial vehicle (UAV) to handle actuator faults, disturbances, and input constraints. A robust fault diagnosis based on the H ∞ scheme was designed to estimate the magnitude of a time-varying fault in the presence of disturbances with unknown upper bounds. Once the fault estimation was complete, a fault-tolerant control scheme was proposed for the attitude system, using adaptive sliding mode backstepping control to accommodate the actuator faults, despite actuator saturation limitation and disturbances. The Lyapunov theory was applied to prove the robustness and stability of the closed-loop system under faulty operation. Simulation results show the effectiveness of the fault diagnosis scheme and proposed controller for handling actuator faults.


Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 54
Author(s):  
Minh-Thien Tran ◽  
Dong-Hun Lee ◽  
Soumayya Chakir ◽  
Young-Bok Kim

This article proposes a novel adaptive super-twisting sliding mode control scheme with a time-delay estimation technique (ASTSMC-TDE) to control the yaw angle of a single ducted-fan unmanned aerial vehicle system. Such systems are highly nonlinear; hence, the proposed control scheme is a combination of several control schemes; super-twisting sliding mode, TDE technique to estimate the nonlinear factors of the system, and an adaptive sliding mode. The tracking error of the ASTSMC-TDE is guaranteed to be uniformly ultimately bounded using Lyapunov stability theory. Moreover, to enhance the versatility and the practical feasibility of the proposed control scheme, a comparison study between the proposed controller and a proportional-integral-derivative controller (PID) is conducted. The comparison is achieved through two different scenarios: a normal mode and an abnormal mode. Simulation and experimental tests are carried out to provide an in-depth investigation of the performance of the proposed ASTSMC-TDE control system.


Author(s):  
Jun Zhou ◽  
Jing Chang ◽  
Zongyi Guo

The paper describes the design of a fault-tolerant control scheme for an uncertain model of a hypersonic reentry vehicle subject to actuator faults. In order to improve superior transient performances for state tracking, the proposed method relies on a back-stepping sliding mode controller combined with an adaptive disturbance observer and a reference vector generator. This structure allows for a faster response and reduces the overshoots compared to linear conventional disturbance observers based sliding mode controller. Robust stability and performance guarantees of the overall closed-loop system are obtained using Lyapunov theory. Finally, numerical simulations results illustrate the effectiveness of the proposed technique.


2018 ◽  
Vol 22 (2) ◽  
pp. 788-802
Author(s):  
Ledi Zhang ◽  
Shousheng Xie ◽  
Yu Zhang ◽  
Litong Ren ◽  
Bin Zhou ◽  
...  

Author(s):  
Salman Ijaz ◽  
Mirza T Hamayun ◽  
Lin Yan ◽  
Cun Shi

The research about the dissimilar redundant actuation system has indicated the potential fault-tolerant capability in modern aircraft. This paper proposed a new design methodology to achieve fault-tolerant control of an aircraft equipped with dissimilar actuators and is suffered from vertical tail damage. The proposed design is based on the concept of online control allocation to redistribute the control signals among healthy actuators and integral sliding mode controller is designed to achieve the closed-loop stability in the presence of both component and actuator faults. To cope with severe damage condition, the aircraft is equipped with dissimilar actuators (hydraulic and electrohydraulic actuators). In this paper, the performance degradation due to slower dynamics of electrohydraulic actuator is taken in account. Therefore, the feed-forward compensator is designed for electrohydraulic actuator based on fractional-order control strategy. In case of failure of hydraulic actuator subject to severe damage of vertical tail, an active switching mechanism is developed based on the information of fault estimation unit. Additionally, a severe type of actuator failure so-called actuator saturation or actuator lock in place is also taken into account in this work. The proposed strategy is compared with the existing control strategies in the literature. Simulation results indicate the dominant performance of the proposed scheme. Moreover, the proposed controller is found robust with a certain level of mismatch between the actuator effectiveness level and its estimate.


Author(s):  
Hachmia Faqihi ◽  
Khalid Benjelloun ◽  
Maarouf Saad ◽  
Mohammed Benbrahim ◽  
M. Nabil Kabbaj

<p>One of the most efficient approaches to control a multiple degree-of-freedom robot manipulator is the virtual decomposition control (VDC). However, the use of the re- gressor technique in the conventionnal VDC to estimate the unknown and uncertaities parameters present some limitations. In this paper, a new control strategy of n-DoF robot manipulator, refering to reorganizing the equation of the VDC using the time delay estimation (TDE) have been investigated. In the proposed controller, the VDC equations are rearranged using the TDE for unknown dynamic estimations. Hence, the decoupling dynamic model for the manipulator is established. The stability of the overall system is proved based on Lyapunov theory. The effectiveness of the proposed controller is proved via case study performed on 7-DoF robot manipulator and com- pared to the conventionnal Regressor-based VDC according to some evalution criteria. The results carry out the validity and efficiency of the proposed time delay estimation- based virtual decomposition controller (TD-VDC) approach.</p>


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