IEEE ROBOTICS PROJECTS IN PONDICHERRYHigh-Speed Nonsingular Terminal Switched Sliding Mode Control of Robot Manipulators
Abstract:
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 a 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.
EXISTING SYSTEM:
Sliding mode control (SMC) also has attracted a great amount of interest due to its advantages, such as strong robustness, rapid response, better transient performance, order reduction, and easiness to design and implement[12; 13]. In literatures, various SMC applications can be seen, for example, uncertain nonlinear systems[14¡16], induction motors[17], hypersonic vehicles[18¡20], and observers[21¡23]. SMC is designed to drive and constrain the system state to the sliding mode surface that is defined based on the convergence requirements, in which the closed-loop response becomes totally insensitive to any uncertainty. A characteristic of conventional SMC is that the system state converges to the equilibrium point in infinite time due to the linear sliding mode manifold that is asymptotically stable.
PROPOSED SYSTEM:
In this paper, it is shown that the high-speed nonsingular terminal switched sliding mode (HNT-SSM) which is the representation of different control demands in the different regions of the state space and also enforced by the HNTSSMC, possesses the property of global high-speed convergence compared with the NFTSM, and provides the global non-singularity. The simulation investigation of an application example is conducted to verify the theoretical analysis and the effectiveness of the proposed approach. Terminal sliding mode control is one of the effective finitetime control methods which are frequently employed. Terminal sliding mode (TSM) control[24] has been developed to offer some superior properties compared with the conventional linear sliding-mode control, such as fast and finite-time convergence and higher control precision. However, TSM control has singularity and has slow convergence speed when the system state is at a distance from the equilibrium. Aiming at avoiding the singularity problem in TSM control systems, a non-singular terminal sliding mode (NTSM) control[5] was proposed. To solve the problem of slow convergence speed when the system state is at a distance from the equilibrium in TSM, there appeared fast terminal sliding mode (FTSM) control[25]. Recently, a nonsingular fast terminal sliding mode (NFTSM) control[26], which does not have both the problems of TSM control, was proposed to offer the singularity avoidance and fast convergence speed when being at a distance from the equilibrium.
CONCLUSION:
In this paper, the proposed approach for robot manipulators, which schedules sliding mode controllers according to different control demands in the different regions of the state space, allows control performance enhancement. And the HNT-SSM simultaneously has the property of global highspeed convergence, and provides the global non-singularity. Further, the effectiveness of the proposed approach and the theoretical analysis is validated by simulation.
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