Dead Zone Compensation and Adaptive Vibration Control of Uncertain Spatial Flexible Riser Systems

TLDR

The article proposes a framework for dead‑zone compensation and robust adaptive vibration control of uncertain spatial flexible riser systems. The authors model nonsymmetric dead‑zone nonlinearity as a desired control input plus an extra nonlinear error, then treat input errors and extrinsic disturbances as an unknown disturbance‑like term to develop a robust adaptive vibration control law with online updating that reduces oscillations and compensates uncertainties and dead zones. The resulting controller guarantees bounded Lyapunov stability and demonstrates improved control performance with suitable design parameters.

Abstract

This article provides a framework of dead zone compensation and robust adaptive vibration control for uncertain spatial flexible riser systems. First, nonsymmetric dead zone nonlinearity is represented in the form of the desired control input with the addition of an extra nonlinear input error. Second, by visualizing those input errors and extrinsic disturbances as an unknown "disturbance-like" term, a new robust adaptive vibration control technology and online updating laws can be constructed for riser systems to guarantee the oscillation reduction and compensation of uncertainties and dead zone. Third, the constructed control ensures and achieves bounded Lyapunov stability in the controlled system. Ultimately, control performances are demonstrated with appropriate design parameters.