A Structure-Inspired Disturbance Observer for Finite-Dimensional Mechanical Systems

• Published in: IEEE transactions on control systems technology Vol. 32; no. 2; pp. 1 - 16
• Main Authors: Chen, Y.-C., Woolsey, C. A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-03-2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Computational modeling; Convergence; Disturbance observer (DO); Disturbance observers; Mathematical models; Measurement uncertainty; Mechanical systems; structure-inspired design; Underwater vehicles; Vehicle dynamics
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2023.3327510

This article describes a disturbance observer (DO) design for systems whose dynamics are piecewise differentiable and satisfy certain structural conditions. Provided a Lipschitz continuity condition holds with a sufficiently small Lipschitz constant-a condition that is implied by "sufficiently slow" dynamics-the observer ensures local ultimate boundedness of the disturbance estimate error, which converges exponentially to a positively invariant set whose size can be made arbitrarily small. This observer is appropriate for finite-dimensional mechanical systems. We demonstrate the design in two examples-a tutorial example of a nonlinear mass-damper-spring system and a practical example of an experimental underwater vehicle.