Mode Control For Underactuated Systems Research Articles

Adaptive fuzzy sliding mode control for underactuated systems with time-varying sensor faults

ABSTRACT The tracking control problem of a class of underactuated systems that have time-varying additive and multiplicative sensor faults is studied in this paper. A composite sliding mode surface is established, and the fuzzy logic system is used to estimate the unknown term in the system. The impact of sensor faults can be counteracted by using the proposed method, which also guarantees the tracking errors converge to zero and the signals in the closed-loop system are bounded. Furthermore, the usefulness of the designed control strategy is certified via a numerical simulation.

Sliding mode control for underactuated system with input constraint based on RBF neural network and Hurwitz stability analysis

AbstractThe sliding mode control method is proposed for a class of underactuated systems with input constraint in this paper. The properties of hyperbolic tangent function are used to deal with input constraint. Furthermore, a radial basis function (RBF) neural network is adopted to achieve the approximation of the unknown function and the projection mapping operator is used to further guarantee the bounded approximation. The control law is designed by using the Lyapunov's direct method, and the stability is conducted by using Hurwitz stability analysis. In the simulation part, two examples are listed, including a simple underactuated system and an underactuated inverted pendulum system, which can all be transformed into the model style studied in this paper to illustrate the effectiveness of the proposed control law. At last, the conclusion is summarized.

Adaptive global sliding mode control of underactuated systems using a super-twisting scheme: an experimental study

The control problem of underactuated systems with external perturbations is investigating in this paper. Using the super-twisting-based global sliding mode control (GSMC) method, an original control law is proposed to guarantee removal of the reaching mode and obtain the robustness and exponential stability of the underactuated systems. Via the offered scheme, a robust control law is designed so that the state trajectories of the underactuated systems are convergent to the global sliding surface in an exponential manner. Moreover, this article develops an adaptive super-twisting algorithm for these systems. The adaptive-tuning controller eliminates the need of the knowledge about upper bound of the exterior disturbance. The discontinuous sign function appears in the controller derivative; as a result, the actual control signal reached after integration is continuous and free of chattering. Demonstrative simulations on a cart–inverted pendulum system as well as an experimental study are presented to show the effectiveness and applicability of the proposed technique.

Decoupled Backstepping Sliding Mode Control of Underactuated Systems with Uncertainty: Experimental Results

In this paper, a decoupled backstepping sliding mode control method is proposed to control underactuated systems under uncertainties and disturbances. The sliding mode control technique and the backstepping control technique are combined owing to their merits. Since the design methodology is based on the Lyapunov theorem, the stability of the system is guaranteed. The effectiveness of the proposed method is verified by the experimental results of the controller which is applied to a nonlinear, underactuated inverted pendulum system. The experimental results show that the decoupled backstepping sliding mode control achieves a satisfactory control performance rather than the decoupled sliding mode controller and the proposed method provides a robust performance to overcome parametric uncertainties where the decoupled sliding mode control fails.

Integral backstepping sliding mode control for underactuated systems: Swing-up and stabilization of the Cart–Pendulum System

In this paper an integral backstepping sliding mode controller is proposed for controlling underactuated systems. A feedback control law is designed based on backstepping algorithm and a sliding surface is introduced in the final stage of the algorithm. The backstepping algorithm makes the controller immune to matched and mismatched uncertainties and the sliding mode control provides robustness. The proposed controller ensures asymptotic stability. The effectiveness of the proposed controller is compared against a coupled sliding mode controller for swing-up and stabilization of the Cart–Pendulum System. Simulation results show that the proposed integral backstepping sliding mode controller is able to reject both matched and mismatched uncertainties with a chattering free control law, while utilizing less control effort than the sliding mode controller.

On estimation of the domain of attraction for sliding mode control of underactuated nonlinear systems

SUMMARYA system is considered underactuated if the number of the actuator inputs is less than the number of degrees of freedom for the system. Sliding mode control for underactuated systems has been shown to be an effective way to achieve system stabilization. It involves exponentially stable sliding surfaces so that when the closed‐loop system trajectory reaches the surface, it moves along the surface while converging to the origin. In this paper, a general framework that provides sufficient conditions for asymptotic stabilization of underactuated nonlinear systems using sliding mode control in the presence of system uncertainties is presented. Specifically, it is shown that the closed‐loop system trajectories reach the sliding surface in finite time, and a constructive methodology to determine exponential stability of the closed‐loop system on the sliding surface is developed, which ensures asymptotic stability of the overall closed‐loop system. Furthermore, the aforementioned framework provides the basis to determine an estimate of the domain of attraction for the closed‐loop system with uncertainties. Finally, the results developed in the paper are experimentally validated using a linear inverted pendulum testbed to show a good match between the actual domain of attraction of the upward equilibrium state of the pendulum and its analytical estimate.Copyright © 2012 John Wiley & Sons, Ltd.