scholarly journals A light cable-driven manipulator developed for aerial robots: Structure design and control research

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092642
Author(s):  
Yaoyao Wang ◽  
Rui Zhang ◽  
Feng Ju ◽  
Jinbo Zhao ◽  
Bai Chen ◽  
...  
Keyword(s):  
Time Delay ◽  
Sliding Mode ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Sliding Mode Controller ◽  
Moving Mass ◽  
Terminal Sliding Mode ◽  
Aerial Robots ◽  
Model Free ◽  
Nonsingular Terminal Sliding Mode

To effectively reduce the mass and simplify the structure of traditional aerial manipulators, we propose novel light cable-driven manipulator for the aerial robots in this article. The drive motors and corresponding reducers are removed from the joints to the base; meanwhile, force and motion are transmitted remotely through cables. Thanks to this design, the moving mass has been greatly reduced. In the meantime, the application of cable-driven technology also brings about extra difficulties for high-precise control of cable-driven manipulators. Hence, we design a nonsingular terminal sliding mode controller using time-delay estimation. The time-delay estimation is applied to obtain lumped system dynamics and found an attractive model-free scheme, while the nonsingular terminal sliding mode controller is utilized to enhance the control performance. Stability is analyzed based on Lyapunov theory. Finally, the designed light cable-driven manipulator and presented time-delay estimation-based nonsingular terminal sliding mode controller are analyzed. Corresponding results show that (1) our proposed cable-driven manipulator has high load to mass ratio of 0.8 if we only consider the moving mass and (2) our proposed time-delay estimation-based nonsingular terminal sliding mode is model-free and can provide higher accuracy than the widely used time-delay estimation-based proportional–derivative (PD) controller.

Practical continuous nonsingular terminal sliding mode control of a cable-driven manipulator developed for aerial robots

2020 ◽  
Vol 234 (9) ◽  
pp. 1011-1023
Author(s):  
Jinbo Zhao ◽  
Yaoyao Wang ◽  
Dan Wang ◽  
Feng Ju ◽  
Bai Chen ◽  
...  
Keyword(s):  
Time Delay ◽  
Sliding Mode ◽  
Fuzzy Logic System ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Sliding Mode Controller ◽  
Terminal Sliding Mode ◽  
Aerial Robots ◽  
Nonsingular Terminal Sliding Mode ◽  
Logic System

With the increasing demand for air operations, in this article, a control algorithm is proposed for a novel light cable-driven manipulator developed for aerial robots. On account of the control problem of cable-driven manipulators, we design a time delay estimation–based nonsingular terminal sliding mode controller with a fuzzy logic system to further improve the precision of joint position tracking. First, time delay estimation technique is adopted to estimate unknown dynamics of the manipulator system. And thanks to time delay estimation, accurate dynamic model is not needed and thus the controller is model-free which makes it more practical. The main part of the controller is nonsingular terminal sliding mode which ensures satisfactory tracking precision and good robustness under time delay estimation error and external disturbances. Besides, the boundary layer is introduced for reducing chattering and was regulated by a fuzzy logic system to realize a faster convergence. Global stability and finite time convergence to equilibrium of the closed-loop control system are analyzed using Lyapunov stability theory. Finally, comparative experiments are conducted through a newly designed planar cable-driven manipulator. Experimental results show that the proposed controller has a better performance compared with a conventional nonsingular terminal sliding mode controller while control effort is almost the same.

scholarly journals Task Space Trajectory Tracking Control of Robot Manipulators with Uncertain Kinematics and Dynamics

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Xichang Liang ◽  
Yi Wan ◽  
Chengrui Zhang
Keyword(s):  
Time Delay ◽  
Sliding Mode ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Kinematics And Dynamics ◽  
Task Space ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode

To improve the tracking precision of robot manipulators’ end-effector with uncertain kinematics and dynamics in the task space, a new control method is proposed. The controller is based on time delay estimation and combines with the nonsingular terminal sliding mode (NTSM) and adaptive fuzzy logic control scheme. Kinematic parameters are not exactly required with the consideration of kinematic uncertainties in the controller. No dynamic models or numerous parameters of the robot manipulator system are required with the use of TDE. Thus, the controller is simple structure and suitable for practical applications. Furthermore, errors caused by time delay estimation are compensated by the adaptive fuzzy nonsingular terminal sliding mode scheme. The simulation is performed on a 2-DOF robot manipulator with three cases in the task space. The results show that the proposed controller provides faster convergence rate and higher tracking precision than TDE based NTSM and improved TDE based NTSM controller.

Joint space tracking control of underwater vehicle-manipulator systems using continuous nonsingular fast terminal sliding mode

2017 ◽  
Vol 232 (4) ◽  
pp. 448-458 ◽  
Author(s):  
Yaoyao Wang ◽  
Bai Chen ◽  
Hongtao Wu
Keyword(s):  
Time Delay ◽  
Tracking Control ◽  
Sliding Mode ◽  
Underwater Vehicle ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Control Performance ◽  
Terminal Sliding Mode ◽  
Model Free ◽  
Fast Terminal Sliding Mode

To ensure satisfactory control performance for the underwater vehicle-manipulator systems, a novel continuous nonsingular fast terminal sliding mode controller is proposed and investigated using time delay estimation in this article. Complex lumped unknown dynamics including the strong nonlinear couplings and external disturbance are properly compensated with time delay estimation, which are mainly based on the time-delayed signals of underwater vehicle-manipulator systems and can provide with a fascinating model-free feature. Afterwards, the satisfactory tracking control performance and good robustness under heavy lumped uncertainties are ensured using the continuous nonsingular fast terminal sliding mode term with a fast terminal sliding mode–type reaching law. Therefore, the proposed controller is easy to use thanks to time delay estimation, and can ensure good control performance owing to continuous nonsingular fast terminal sliding mode. Stability of the closed-loop control system is analyzed using Lyapunov stability theory, and theoretical tracking errors are calculated and presented. Finally, the effectiveness and advantages of the proposed controller are demonstrated through comparative 7-degree-of-freedom pool experiments.

scholarly journals Practical Tracking Control of Piezoelectric Actuators with Time-delay Estimation and Nonsingular Terminal Sliding Mode

2020 ◽  
Author(s):  
Hai-Ping Lin ◽  
Han-Lie Gu ◽  
Shengdong Yu ◽  
Jin-Yu Ma ◽  
Hong-Tao Wu
Keyword(s):  
Time Delay ◽  
Control Strategy ◽  
Sliding Mode ◽  
Engineering Application ◽  
Piezoelectric Actuators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Unknown Boundary ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode

Abstract A novel type of nonlinear robust control strategy is proposed in view of uncertain nonlinear factors, such as hysteresis, creep, and high-frequency vibration, of piezoelectric actuators (PEAs). This strategy can be used for the precise trajectory tracking of PEAs. The Bouc–Wen dynamic model is reasonably simplified to facilitate engineering application. The hysteresis term is summarized as an unknown term to avoid its nonlinear parameter identification. The controller robustness is achieved due to the nonsingular terminal sliding mode control, and the online estimation of unknown disturbances is realized because of the delay estimation technology; thus, no prior knowledge of the unknown boundary of the system is required. The precision robust differentiator is used to estimate the speed and acceleration signals in real time on the basis of the obtained displacement signals. The closed-loop stability of the system is proved by the Lyapunov criterion. Experimental results show that the proposed control strategy performs better than the traditional time-delay estimation control in terms of control accuracy and energy conservation. Therefore, the proposed control strategy can play an important role in the micro/nanofield driven by PEAs.

Model-free robust finite-time force tracking control for piezoelectric actuators using time-delay estimation with adaptive fuzzy compensator

2019 ◽  
Vol 42 (3) ◽  
pp. 351-364
Author(s):  
Shengzheng Kang ◽  
Hongtao Wu ◽  
Xiaolong Yang ◽  
Yao Li ◽  
Yaoyao Wang
Keyword(s):  
Time Delay ◽  
Finite Time ◽  
Sliding Mode ◽  
Piezoelectric Actuators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Terminal Sliding Mode ◽  
Adaptive Fuzzy ◽  
Model Free ◽  
Force Tracking

A robust and practical force control system is crucial to the sensitive piezo-driven micromanipulation applications. This paper presents a new model-free robust finite-time force tracking controller for piezoelectric actuators (PEAs). The proposed controller composes of three intuitive terms: (1) a time-delay estimation (TDE) term that eliminates the requirement of detailed information about the PEA system, realizing model-free control; (2) a fast integral terminal sliding mode-based desired error dynamics injection term that ensures fast convergence and high tracking precision; (3) a correcting term based on adaptive fuzzy logic system that compensates for TDE errors caused by discontinuous nonlinearities and improves the robustness of the system. Force differential signal used in the controller is estimated online by a force state estimator. Stability of the closed-loop system and finite-time convergence are analyzed in theory. Comparative experiments are carried out on a PEA system with two superposed PEAs. Results show that the proposed control strategy has faster convergence, higher tracking accuracy and stronger robustness compared with the traditional TDE-based force controllers.

scholarly journals Robust precision motion control of piezoelectric actuators using fast nonsingular terminal sliding mode with time delay estimation

2018 ◽  
Vol 52 (1-2) ◽  
pp. 11-19 ◽  
Author(s):  
Shengdong Yu ◽  
Jinyu Ma ◽  
Hongtao Wu ◽  
Shengzheng Kang
Keyword(s):  
Time Delay ◽  
Motion Control ◽  
Control Method ◽  
Sliding Mode ◽  
Piezoelectric Actuators ◽  
Time Delay Estimation ◽  
Delay Estimation ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Precision Motion

Background: Piezoelectric actuators are widely used in many micro/nano-manipulation applications, but their positioning accuracy are badly affected by their inherent nonlinear hysteresis and creep. To solve this problem, this paper presents a new robust motion-control method for piezoelectric actuators with fast nonsingular terminal sliding mode based on time delay estimation. Method: The proposed controller needs no detailed information about the hysteresis and other nonlinearities of the system, leading to a simple and model-free characteristic due to the time delay estimation and ensures fast convergence and high tracking accuracy thanks to the nonsingular terminal sliding-mode surface and fast terminal sliding mode -type reaching law. A robust exact differentiator is adopted to estimate the velocity and accelerationinformation online, and it overcomes the limitation of only available position measurements. The finite-time convergence and stability of the closed-loop system are proved by using a Lyapunov function. Results: Experimental results show that the proposed control strategy has faster convergence and higher tracking precision compared with a traditional time delay control. Conclusion: The proposed control strategy can be widely used as an effective control method for high-precision motion control of piezoelectric actuators.

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