Non-singular terminal sliding mode control and its application for robot manipulators (original) (raw)
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IEEE Access
This paper presents an adaptive terminal sliding mode control algorithm for robot manipulators. The contribution of our control method is that the suggested controller can enable the advantages of non-singular terminal sliding mode control such as non-singularity, high robustness, small transient error, and finite time convergence. To develop the suggested system, a non-singular terminal sliding variable is selected and does not have any complex-value or constraints of the exponent in conventional TSMC. Therefore, it prevents the singularity that occurs in the conventional TSMC and eliminates the reaching phase glitch. Accordingly, the suggested system can ensure that the controlled variables reach the desired values within a randomly known finite time using an efficiently smooth and chattering-free definite control input. In addition, sliding motion in finite time can be achieved by employing the adaptive self-tuning rules with no prior information regarding the upper bounds of undefined parameters (e.g., friction, disturbances, and uncertainties). Furthermore, the finite-time convergence and global stability of the proposed algorithm are proved by the Lyapunov stability theory. Finally, the proposed control algorithm is applied to the joint position tracking control simulation for a 3-DOF PUMA560 robot. The trajectory tracking performance of the proposed method is compared with those of the conventional terminal sliding mode control and the conventional continuous sliding mode control. This comparison shows the efficiency and superiority of the proposed algorithm.
IEEE Access
This paper proposes a controller-observer strategy for a class of second-order uncertain nonlinear systems with only available position measurement. The third-order sliding mode observer is first introduced to estimate both velocities and the lumped uncertain terms of system with high accuracy, less chattering, and finite time convergency of estimation errors. Then, the proposed controller-observer strategy is designed based on non-singular fast terminal sliding mode sliding control and proposed observer. Thanks to this combination, the proposed strategy has some superior properties such as high tracking accuracy, chattering phenomenon reduction, robustness against the effects of the lumped uncertain terms, velocity measurement elimination, finite time convergence, and faster reaching sliding motion. Especially, two period times, before and after the convergence of the velocity estimation takes place, are considered. The finite time stability of proposed controller-observer method is proved by using the Lyapunov stability theory. Final, the proposed strategy is applied to robot manipulator system and its effectiveness is verified by simulation results, in which a PUMA560 robot manipulator is employed.
Non-singular terminal sliding mode control of rigid manipulators
Automatica, 2002
This paper presents a global non-singular terminal sliding mode controller for rigid manipulators. A new terminal sliding mode manifold is ÿrst proposed for the second-order system to enable the elimination of the singularity problem associated with conventional terminal sliding mode control. The time taken to reach the equilibrium point from any initial state is guaranteed to be ÿnite time. The proposed terminal sliding mode controller is then applied to the control of n-link rigid manipulators. Simulation results are presented to validate the analysis. ? : S 0 0 0 5 -1 0 9 8 ( 0 2 ) 0 0 1 4 7 -4
A Novel Fast Terminal Sliding Mode Tracking Control Methodology for Robot Manipulators
Applied Sciences
This paper comes up with a novel Fast Terminal Sliding Mode Control (FTSMC) for robot manipulators. First, to enhance the response, fast convergence time, against uncertainties, and accuracy of the tracking position, the novel Fast Terminal Sliding Mode Manifold (FTSMM) is developed. Then, a Supper-Twisting Control Law (STCL) is applied to combat the unknown nonlinear functions in the control system. By using this technique, the exterior disturbances and uncertain dynamics are compensated more rapidly and more correctly with the smooth control torque. Finally, the proposed controller is launched from the proposed sliding mode manifold and the STCL to provide the desired performance. Consequently, the stabilization and robustness criteria are guaranteed in the designed system with high-performance and limited chattering. The proposed controller runs without a precise dynamic model, even in the presence of uncertain components. The numerical examples are simulated to evaluate the effe...
Nonsingular fast terminal sliding-mode control for nonlinear dynamical systems
International Journal of Robust and Nonlinear Control, 2010
This paper investigates fast finite-time control of nonlinear dynamics using terminal sliding-mode (TSM) scheme. Some new norms of fast TSM strategies are proposed, and a faster convergence rate is established in comparison with the conventional fast TSM. A novel concept of nonsingular fast TSM, which is able to avoid the possible singularity during the control phase, is adopted in the robust high-precision control of uncertain nonlinear systems. Numerical simulation on a two-link rigid robot manipulator demonstrates the effectiveness of the proposed algorithm.
Robust control by adaptive Non-singular Terminal Sliding Mode
Engineering Applications of Artificial Intelligence, 2017
Based on the principles of the Non-singular Terminal Sliding Mode Control (NTSMC), a new control law along with an Unscented Kalman Filter (UKF) has been proposed for robotic manipulators, that can tolerate external disturbances and noises with unknown statistics. First, a neural network module has been used as a discontinuous control part of the NTSMC to enhance the performance of the controller due to chattering phenomenon. Furthermore, a new methodology is proposed which is based on a modified evolutionary algorithm (charged systems search) to estimate the system states by the UKF and the measurement and process noise covariances. To compare this evolutionary method with classical methods, an optimal Unscented Kalman Filter (UKF) algorithm has been introduced that estimates the noise statistics recursively within the algorithm. The proposed control method and observer have been simulated on a 6-DOF robot manipulator.
Robust Nonsingular Fast Terminal Sliding Mode Control in Trajectory Tracking for a Rigid Robotic Arm
Automatic Control and Computer Sciences, 2019
In this paper, a novel concept of robust Nonsingular Fast Terminal Sliding Mode controller (NFTSMC) is adopted for the trajectory tracking problem of a non-linear system. The developed controller is based on NFTSM controller and approach. The use of the NFTSM controller offers a fast convergence rate, avoids singularities, but still suffers from chattering. In order to overcome this limitation, a new term in the control law is inspired by the technique of it interferes by managing uncertainties and external disturbances without knowing their upper bound. Stability analysis of the closed-loop system is accomplished using the Lyapunov criterion. Several simulation results are given to show the effectiveness of the proposed approach.
Nonsingular Terminal Sliding Mode Control Based on Novel Reaching Law for Nonlinear Uncertain System
Applied Mechanics and Materials, 2013
Novel reaching law to nonsingular terminal sliding mode control for the control of the second order nonlinear uncertain system is introduced in this paper. The problems of singularity, chattering and slow convergence of the terminal sliding mode control, and verify the stability of the new controller is analyzed. Due to the premise of eliminating the singular value in the nonsingular terminal sliding mode control, the new reaching law based on the power reaching law enables the finite time convergence of the system equilibrium. By applying the new controller to the inverted pendulum system, the sliding surface had been proved fast and the system chattering had been reduced at the same time. Simulation results indict that the system converges to the equilibrium in a short time and the proposed method is feasible and effective.
Nonsingular terminal sliding mode control of nonlinear second-order systems with input saturation
International Journal of Robust and Nonlinear Control, 2015
This paper proposes the use of a novel nonsingular Terminal Sliding surface for the finite-time robust stabilization of second order nonlinear plants with matched uncertainties. Mathematical characteristics of the proposed surface are such that a fixed bound naturally exists for the settling time of the state variable, once the surface has been reached. A simple redesign of the control input able to ensure the feature of fixed-time reaching of the sliding surface will be also presented, and fixed-time stability will be guaranteed by the proposed Terminal Sliding Mode Control design method. A careful simulation study has been performed using a benchmark system taken from the literature.
High-speed Nonsingular Terminal Switched Sliding Mode Control of Robot Manipulators
This paper proposes a high-speed nonsingular terminal switched sliding mode control (HNT-SSMC) strategy for robot manipulators. The proposed approach enhances the control system performance by switching among appropriate sliding mode controllers according to different control demands in different regions of the state space. It is shown that the highspeed nonsingular terminal switched sliding mode (HNT-SSM) which is the representation of different control demands and enforced by the HNT-SSMC has the property of global highspeed convergence compared with the nonsingular fast terminal sliding mode (NFTSM), and provides the global non-singularity. The simulation study of an application example is carried out to validate the effectiveness of the proposed strategy.