Abstract:This paper presents a new approach in modeling and control of multi‐input multi‐output (MIMO) systems that have non‐differentiable operating points. A circle criterion is introduced at the non‐differentiable operating points to divide the entire operating region into two parts. Takagi‐Sugeno fuzzy models are developed in each part, and a switching framework is introduced to model the operating region. Accordingly, a sliding mode controller (SMC) is developed. The proposed modeling and controller are implemente… Show more
“…Theorem 1. Under Assumption 1, if the controller is defined as (7) and the sliding surface is designed as Equation ( 6), then the sliding variables and the tracking errors are ultimately uniformly bounded.…”
Section: Design Of Third-order Sliding Mode Controllermentioning
confidence: 99%
“…Many methods have now been developed to control nonlinear dynamical systems. Some examples of the robust control techniques that have been proposed include sliding mode control (SMC) [1], adaptive control [2][3][4][5], fuzzy control [6][7][8], backstepping [9], model predictive control [10], integral-type saturated control [11], proportional-derivative control [12], and observer-based quantized output feedback control [13].…”
This paper proposes a third‐order sliding mode controller for nonlinear multivariable systems with uncertain parameters and subject to external disturbances. The controller achieves fast convergence rate, high tracking accuracy, and a reduced level of chattering. The stability of the controller and its global ultimately uniform convergence is proved by the Lyapunov stability theory. Simulation results on a single inverted pendulum system are given to illustrate the effectiveness of the proposed control scheme by comparing it with methods such as a second‐order supertwisting controller, a third‐order supertwisting controller, and an integral terminal third‐order sliding mode controller.
“…Theorem 1. Under Assumption 1, if the controller is defined as (7) and the sliding surface is designed as Equation ( 6), then the sliding variables and the tracking errors are ultimately uniformly bounded.…”
Section: Design Of Third-order Sliding Mode Controllermentioning
confidence: 99%
“…Many methods have now been developed to control nonlinear dynamical systems. Some examples of the robust control techniques that have been proposed include sliding mode control (SMC) [1], adaptive control [2][3][4][5], fuzzy control [6][7][8], backstepping [9], model predictive control [10], integral-type saturated control [11], proportional-derivative control [12], and observer-based quantized output feedback control [13].…”
This paper proposes a third‐order sliding mode controller for nonlinear multivariable systems with uncertain parameters and subject to external disturbances. The controller achieves fast convergence rate, high tracking accuracy, and a reduced level of chattering. The stability of the controller and its global ultimately uniform convergence is proved by the Lyapunov stability theory. Simulation results on a single inverted pendulum system are given to illustrate the effectiveness of the proposed control scheme by comparing it with methods such as a second‐order supertwisting controller, a third‐order supertwisting controller, and an integral terminal third‐order sliding mode controller.
“…However, since the robotic manipulator is a system with nonlinear and complex perturbations, the actual control is susceptible to modeling errors, friction, and external disturbances, which all increase the difficulty of control. In response to the problems of nonlinear systems, scholars have developed different control methods to improve them, such as neural network control [3,4], fuzzy control methods [5][6][7][8][9], backstepping control methods [10][11][12], and sliding mode control (SMC) methods [13][14][15][16][17][18].…”
Considering that in the trajectory tracking control of a nonlinear robotic manipulator system, the control effect is easily limited by the initial state of the system, and the system has modeling error, unknown disturbance, and friction in the actual control, to overcome the above problems, a fixed-time sliding mode control (SMC) strategy based on adaptive disturbance observer (ADO) is developed in this paper. Firstly, feedforward compensation of the system is achieved by developing an ADO to accurately estimate the compound disturbances in the system. Second, a new fixed-time sliding mode (SM) surface is presented to overcome the singularity issue and accelerate the error convergence. In addition, to enhance the performance of the reaching phase, a variable exponential power reaching law (VEPRL) is developed, which can effectively adjust the convergence rate. Through rigorous theoretical analysis, it is shown that the system state can be stabilized at a fixed time, and an upper bound on the convergence time is also given. Finally, the effectiveness of the control method is verified by comparing it with different control schemes in simulation.
K E Y W O R D Sadaptive disturbance observer (ADO), fixed time, robotic manipulator system, sliding mode (SM) surface, variable exponential power reaching law (VEPRL)
“…When the nonlinear term of the system does not meet the Lipschitz condition, it is difficult to use the existing research methods. The T-S fuzzy model can use multiple local linear system models to approximate the global nonlinear system model [17,18], which provides a novel idea for the investigation of nonlinear SDC systems. The tracking control problem of fuzzy stochastic distribution sampled-data systems is studied in [19].…”
The fault tolerant control (FTC) problem based on rational entropy performance criteria is researched for fuzzy descriptor stochastic distribution networked control (SDNC) systems with packet dropout. The independent Bernoulli distribution is employed to describe the packet dropout in the feedback channel. The static model and the dynamic model of descriptor SDNC systems are built up by the rational square‐root fuzzy logic model (FLM) and the T‐S fuzzy model, respectively. When the given output probability density function (PDF) is not known, the minimization of output randomness becomes an important control target. First, the unknown fault is estimated by developing the fuzzy fault estimation observer. Then, the fault tolerant controller with the fault compensation is designed so that the output of the descriptor SDNC system remains with the minimum uncertainty after the fault occurs. A simulation example is supplied to prove the proposed scheme.
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