Fuzzy impedance-based control with fast terminal sliding mode force control loop for a series elastic actuator system

2021 ◽  
pp. 014233122110436
Author(s):  
Seyed Ali Moafi ◽  
Farid Najafi
Keyword(s):  
Force Control ◽  
Fuzzy Logic Controller ◽  
Sliding Mode ◽  
Control Loop ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Series Elastic Actuator ◽  
Control Scheme ◽  
Fast Terminal Sliding Mode ◽  
Series Elastic

This paper proposes a robust control scheme to accomplish the interaction control problem between a series elastic actuator (SEA) and a flexible environment. The adaptability of the controller to unknown variations and robustness of the controller during interaction of the system with environment are the main aims. The control scheme is based on a fuzzy impedance control approach and consists of an inner fast terminal sliding mode force control loop. An experimental setup is designed to prove the efficiency of the developed controller. The experimental results confirm that the proposed fuzzy logic controller guarantees the sensitivity of the controlled system to unpredictable variations. Moreover, by applying the fast terminal sliding mode algorithm for the inner force control loop, the system has faster convergence to the reference path compared with similar control methods found in the literature.

Fast Terminal Fuzzy Sliding Mode Control for Attitude of Flapping Wing Micro Aerial Vehicle

2013 ◽  
Vol 427-429 ◽  
pp. 1179-1182
Author(s):  
Sheng Bin Hu ◽  
Jin Yuan Xu ◽  
Xuan Wu ◽  
Chi Zhang ◽  
Yi Hao He
Keyword(s):  
Sliding Mode ◽  
Flapping Wing ◽  
Sliding Mode Controller ◽  
Terminal Sliding Mode ◽  
Micro Aerial Vehicle ◽  
Fuzzy Sliding Mode Control ◽  
Control Scheme ◽  
Fast Terminal Sliding Mode ◽  
Aerial Vehicle ◽  
Fuzzy Sliding Mode

A fast terminal fuzzy sliding mode control scheme for the attitude of flapping wing micro aerial vehicle is proposed in this paper. Based on the feedback linearization technique, a fast terminal sliding mode controller is designed. To diminish the chattering in the control input, a fuzzy controller is designed to adjust the generalized gain of fast terminal fuzzy sliding mode controller according to fast terminal sliding mode surface. The stability of the control algorithm is verified by using Lyapunov theory. Simulation results show that the proposed control scheme is effective.

Adaptive sliding mode observer–based integral sliding mode model-free torque control for elastomer series elastic actuator–based manipulator

2021 ◽  
pp. 095965182110647
Author(s):  
Yangchun Wei ◽  
Haoping Wang ◽  
Yang Tian
Keyword(s):  
Sliding Mode ◽  
Sliding Mode Observer ◽  
Torque Control ◽  
Terminal Sliding Mode ◽  
Series Elastic Actuator ◽  
Model Free ◽  
Output Torque ◽  
Nonsingular Terminal Sliding Mode ◽  
Model Free Control ◽  
Series Elastic

In this brief, an adaptive nonsingular terminal sliding mode observer–based adaptive integral terminal sliding mode model-free control is proposed for the trajectory tracking control of the output torque of elastomer series elastic actuator–based manipulator. Considering the tip load and its external disturbance, an elastomer series elastic actuator–based manipulator model is established. In order to realize the output torque tracking control of elastomer series elastic actuator–based manipulator, by using the characteristics of elastomer series elastic actuator, the output torque control is transformed into position control. Based on the idea of model-free control, an ultra-local model is applied to approximate the dynamic of the manipulator, and all the model information is considered as an unknown lumped disturbance. The adaptive nonsingular terminal sliding mode observer is designed to estimate the lumped disturbance, and the absolute value of the tracking error is introduced into the sliding surface to make the selection of parameters more flexible. Then, on the basis of adaptive nonsingular terminal sliding mode observer, the adaptive integral terminal sliding mode model-free control is proposed under model-free control framework. The design and analysis of both observer and controller do not rely on accurate model information. Finally, the performance of the proposed method is verified by simulation results.

Flexible air-breathing hypersonic vehicle control based on a novel non-singular fast terminal sliding mode control and nonlinear disturbance observer

2016 ◽  
Vol 231 (11) ◽  
pp. 2132-2145 ◽  
Author(s):  
Xiaoqian Yang ◽  
Jian Li ◽  
Yi Dong
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Hypersonic Vehicle ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Nonlinear Disturbance Observer ◽  
Mode Control ◽  
Control Scheme ◽  
Fast Terminal Sliding Mode ◽  
Nonlinear Disturbance

A new control scheme for flexible air-breathing hypersonic vehicle is designed in this paper based on non-singular fast terminal sliding mode control and nonlinear disturbance observer. The proposed control scheme is derived from basic back-stepping method, which is capable of handling the higher-order nonlinear system, and a novel terminal sliding mode control method is designed for the last step to promise the finite time convergence and improve the steady-state precision. Meanwhile, a command filter is used to avoid the “explosion of complexity” in traditional back-stepping method. To overcome inevitable uncertainties as well as cross couplings between flexible and rigid modes, NDO is introduced to estimate diverse uncertainties. Thus flexible modes and uncertainties can be suppressed simultaneously. The convergence of overall closed-loop system states is proved via Lyapunov analysis. Numerical simulations show the effectiveness and advantages of the proposed control strategy.

Chattering-free adaptive fast convergent terminal sliding mode controllers for position tracking of robotic manipulators

2015 ◽  
Vol 230 (4) ◽  
pp. 514-526 ◽  
Author(s):  
Shaoming He ◽  
Defu Lin ◽  
Jiang Wang
Keyword(s):  
Sliding Mode ◽  
Robotic Manipulators ◽  
Position Tracking ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Nonsingular Terminal Sliding Mode ◽  
Fast Terminal Sliding Mode ◽  
Sliding Manifold ◽  
Chattering Free ◽  
Chattering Elimination

The paper documents a new continuous adaptive fast terminal sliding mode control approach for position tracking of robotic manipulators. Combining linear sliding mode and terminal sliding mode, a fast nonsingular terminal sliding mode manifold is presented. Considering the discontinuous property of the sign function, which is often used in traditional sliding mode controller and will result in high-freqsency chattering in the control channel, the proposed controller adopts the continuous saturation function for chattering elimination. Besides the continuous property, convergence to the origin asymptotically and in finite time can be guaranteed in theory with the proposed controller, which is quite different from traditional boundary layer technique, where only bounded motion around the sliding manifold can be ensured. For asymptotic stability, it is only required that the lumped uncertainty is bounded, but the upper bound may be unknown by virtue of the designed adaptive methodology. The obtained results are applied to the problem of position tracking for robotic manipulators. Detailed simulations with some comparisons under various conditions demonstrate the effectiveness of the proposed method.

scholarly journals Smooth Adaptive Finite Time Guidance Law with Impact Angle Constraints

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Bin Zhao ◽  
Jun Zhou
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Impact Angle ◽  
Guidance System ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Adaptive Law ◽  
Target Acceleration ◽  
Control Scheme ◽  
Fast Terminal Sliding Mode

A smooth guidance law for intercepting a maneuvering target with impact angle constraints is documented based on the nonsingular fast terminal sliding mode control scheme and adaptive control scheme. Different from the traditional adaptive law which is used to estimate the unknown upper bound of the target acceleration, a new adaptive law is proposed to estimate the square of target acceleration bound, which avoids the use of the nonsmooth signum function and therefore ensures the smoothness of the guidance law. The finite time convergence of the guidance system is guaranteed based on the Lyapunov method and the finite time theory. Simulation results indicate that under the proposed guidance law the missile can intercept the target with a better accuracy at a desired impact angle in a shorter time with a completely smooth guidance command compared with the existing adaptive fast terminal sliding mode guidance laws, which shows the superiority of this method.

A novel nonsingular integral terminal sliding mode control scheme in epilepsy treatment

2021 ◽  
pp. 014233122110507
Author(s):  
Moshu Qian ◽  
Zhen Zhang ◽  
Guanghua Zhong ◽  
Cuimei Bo
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Sliding Mode ◽  
Tracking Error ◽  
Lyapunov Theory ◽  
Terminal Sliding Mode ◽  
Loop Control ◽  
Control Approach ◽  
Control Scheme ◽  
Loop Control System

In this paper, a closed-loop brain stimulation control problem is investigated using the nonsingular integral terminal sliding mode (NITSM) control approach. First, the thalamocortical model of epilepsy seizure is given, which is composed of the cortical PY-IN subnetwork and the subcortical RE-TC subsystem. Then, a nonsingular integral terminal sliding mode surface is designed utilizing the derived output tracking error, and the stability of the sliding mode dynamics is proved by Lyapunov approach. Furthermore, a disturbance observer (DOB) based NITSM controller design approach is proposed for the established thalamocortical model, and the reachability of the closed-loop control system under the designed controller is analyzed using Lyapunov theory. Finally, simulation results are given to illustrate the effectiveness and superiority of the designed control scheme.

Force control of an uncertain series elastic actuator system via a fuzzy sliding mode controller and a nonlinear state estimator

2019 ◽  
Vol 234 (4) ◽  
pp. 462-471
Author(s):  
Seyed Ali Moafi ◽  
Farid Najafi
Keyword(s):  
Sliding Mode ◽  
Sliding Mode Controller ◽  
State Estimator ◽  
Series Elastic Actuator ◽  
Control Scheme ◽  
Chattering Free ◽  
Fuzzy Sliding Mode ◽  
Theory Of Lyapunov Stability ◽  
Nonlinear State ◽  
Series Elastic

Nowadays, series elastic actuators play an important role in actuation technology, especially for mechatronics and robotic applications. In this article, the accurate tracking of output force for a series elastic actuator is investigated. In order to achieve this aim, a novel robust control scheme is developed to overcome friction effects, backlash in the drivetrain, measurement noises (sensor inaccuracy) and uncertainties in the dynamic model. The control scheme consists of a fuzzy sliding mode controller and a nonlinear state estimator. The theory of Lyapunov stability is used for the formulation of the proposed controller and also the fuzzy logic strategy is used for tuning the sliding surface parameter in order to achieve accurate and chattering-free performance. Furthermore, a powerful estimator algorithm, unscented H-infinity filter, is added to the control scheme to improve the robustness of the system. Simulation results, as well as experimental analysis, approved the efficiency of the proposed approach in the presence of uncertainties and disturbances.

Fault tolerant control for robotic manipulator using fractional-order backstepping fast terminal sliding mode control

2021 ◽  
pp. 014233122110224
Author(s):  
Zeeshan Anjum ◽  
Yu Guo ◽  
Wei Yao
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Terminal Sliding Mode Control ◽  
Actuator Faults ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Mode Control ◽  
Fast Terminal Sliding Mode

In this paper, the problems of tracking control and finite-time stabilization of a high nonlinear system such as a robotic manipulator in the presence of actuator faults, uncertainties, and external disturbances are explored. In order to improve the performance of the system in the presence of actuator faults, uncertainties and external disturbances a novel fault tolerant control system based on fractional-order backstepping fast terminal sliding mode control is developed in this paper. The control system is developed by employing the results obtained from studies in the fields of fractional-order calculus, backstepping, sliding mode control, Mittag–Leffler stability, and finite-time Lyapunov stability. The performance of the suggested controller is then tested for a PUMA560 robot in which the first three joints are used. The simulation results validate the usefulness of the developed control approach in terms of accuracy of tracking, and convergence speed in the presence of disturbances, uncertainties and actuator faults. The trajectory tracking performance of the developed method is compared with other state of the art approaches such as conventional computed torque control, proportional integral derivative control and nonsingular fast terminal sliding mode control. The simulation results show that the proposed control approach performed better as compared to other control approaches in the presence of actuator faults, uncertainties, and disturbances.

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