Cooperative control of a nonuniform gantry crane with constrained tension

In this paper, we consider the trajectory tracking of a marine surface vessel in the presence of output constraints and uncertainties. An asymmetric barrier Lyapunov function is employed to cope with the output constraints. To handle the system uncertainties, we apply adaptive neural networks to approximate the unknown model parameters of a vessel. Both full state feedback control and output feedback control are proposed in this paper. The state feedback control law is designed by using the Moore–Penrose pseudoinverse in case that all states are known, and the output feedback control is designed using a high-gain observer. Under the proposed method the controller is able to achieve the constrained output. Meanwhile, the signals of the closed loop system are semiglobally uniformly bounded. Finally, numerical simulations are carried out to verify the feasibility of the proposed controller.

Adaptive Neural Network Control of a Marine Vessel With Constraints Using the Asymmetric Barrier Lyapunov Function

In this paper, a neural network (NN) controller is designed to suppress the vibration of a flexible robotic manipulator system with input deadzone. The NN aims to approximate the unknown robotic manipulator dynamics and eliminate the effects of input deadzone in the actuators. In order to describe the system more accurately, the model of the flexible manipulator is constructed based on the lumping spring-mass method. Full state feedback NN control is proposed first and output feedback NN control with a high-gain observer is then devised to make the proposed control scheme more practical. The effect of input deadzone is approximated by a radial basis function neural network (RBFNN) and the unknown dynamics of the manipulator is approximated by another RBFNN. The proposed NN control is able to compensate for the estimated deadzone effect and track the desired trajectory. For the stability analysis, the Lyapunov's direct method is used to ensure uniform ultimate boundedness (UUB) of the closed-loop system. Simulations are given to verify the control performance of the NN controllers comparing with the proportional derivative (PD) controller. At last, the experiments are conducted on the Quanser platform to further prove the feasibility and control performance of the NN controllers.

Vibration Control of a Flexible Robotic Manipulator in the Presence of Input Deadzone

In this brief, the control problem for flexible wings of a robotic aircraft is addressed by using boundary control schemes Inspired by birds and bats, the wing with flexibility and articulation is modeled as a distributed parameter system described by hybrid partial differential equations and ordinary differential equations Boundary control for both wing twist and bending is proposed on the original coupled dynamics, and bounded stability is proved by introducing a proper Lyapunov function The effectiveness of the proposed control is verified by simulations

Control Design for Nonlinear Flexible Wings of a Robotic Aircraft

Adaptive neural networks (NNs) are employed for control design to suppress vibrations of a flexible robotic manipulator. To improve the accuracy in describing the elastic deflection of the flexible manipulator, the system is modeled via the lumped spring-mass approach. Full-state feedback control as well as output feedback control are proposed separately. Aiming at achieving the control objective, uniform ultimate boundedness of the closed-loop system is ensured. Numerical simulations for the lumped model of the flexible robotic system are carried out to verify the performance of the NN control. Finally, the experiments are given to further validate the feasibility of the proposed NN controllers on the Quanser platform.

Neural Network Control of a Flexible Robotic Manipulator Using the Lumped Spring-Mass Model

In this paper, boundary control is designed to suppress transverse vibration of a flexible marine riser with input saturation in the ocean environment. Two cases are investigated: 1) state feedback boundary control, and 2) output feedback boundary control. In order to compensate for the input saturation, we propose an auxiliary system. First, state feedback boundary control with an auxiliary system is proposed when the boundary states of the riser can be measured. Subsequently, output feedback boundary control is developed when there are unmeasurable system states. High-gain observers are employed to estimate those unmeasurable states. Based on Lyapunov's direct method, the proposed control ensures that the deflection of the riser is uniformly bounded in the presence of the ocean disturbances. By choosing a set of appropriate parameters, numerical simulations are provided to verify the effectiveness of the proposed boundary control.

Vibration Control of Flexible Marine Riser Systems With Input Saturation

In this paper, we consider the control problem of a flexible string system in the presence of input saturation. The dynamics of the string system is represented by the coupled partial differential equation and ordinary differential equations. Firstly, in order to suppress the transverse vibration of the flexible string system, full state feedback control is proposed by introducing a well-defined integral Lyapunov function. An auxiliary system is introduced to handle the effect of input saturation, and the proof for the existence and the uniqueness of the solution of the closed-loop system is presented. The exponential stability is achieved through rigorous analysis without any simplification of the dynamics. Subsequently, for the case that some of system states cannot be directly obtained, output feedback control is developed and uniform ultimate boundedness is guaranteed. Finally, the results are illustrated with numerical simulations for verifying the control performance.

Boundary output feedback control of a flexible string system with input saturation

This paper investigates the modeling and vibration control design of a coupled vessel-mooring-riser system. The coupling among the vessel, the mooring lines, and the riser is taken into consideration, and the system is described by a set of partial differential equations and some ordinary differential equations based on energy functions of this system. A control law is proposed at the top boundary of the system to suppress the vibrations of both the mooring lines and the riser. The stability and uniform boundedness of the system under the distributed disturbance are proved via Lyapunov's direct method. Numerical simulations are given to verify the effectiveness of the control law.

http://ieeexplore.ieee.org/iel7/3516/7305854/07061473.pdf

Modeling and Vibration Control of a Coupled Vessel-Mooring-Riser System

In this paper, the control problem is addressed for a hybrid PDE-ODE system that describes a nonuniform gantry crane system with constrained tension. A bottom payload hangs from the top gantry by connecting a flexible cable. The flexible cable is nonuniform due to the spatiotemporally varying tension applied to the system. Cooperative control laws are proposed and the Integral-Barrier Lyapunov Functions are employed for stability analysis of the closed-loop system. Adaption laws are developed for handling parametric uncertainties. The bounded stability is guaranteed through rigorous analysis without any simplification of the dynamics. In the end, numerical simulations are displayed to illustrate the performance of the proposed cooperative control.

http://ieeexplore.ieee.org/iel7/6882077/6895198/06897064.pdf

Xiuyu He

Papers

Vibration Control of Flexible Marine Riser Systems With Input Saturation

Boundary output feedback control of a flexible string system with input saturation

Modeling and Vibration Control of a Coupled Vessel-Mooring-Riser System

Adaptive control design for a nonuniform gantry crane with constrained tension