A nonlinear disturbance observer for robotic manipulators

TLDR

It can be applied in robotic manipulators for various purposes such as friction compensation, independent joint control, sensorless torque control and fault diagnosis. The paper derives a new nonlinear disturbance observer for robotic manipulators. The observer guarantees global exponential stability by selecting design parameters based on maximum velocity and physical parameters, and its performance is demonstrated through friction estimation and compensation on a two‑link manipulator. The new observer overcomes the limitations of existing linear‑based DOs and is validated by simulation and experimental results showing effective performance.

Abstract

A new nonlinear disturbance observer (NDO) for robotic manipulators is derived in this paper. The global exponential stability of the proposed disturbance observer (DO) is guaranteed by selecting design parameters, which depend on the maximum velocity and physical parameters of robotic manipulators. This new observer overcomes the disadvantages of existing DOs, which are designed or analyzed by linear system techniques. It can be applied in robotic manipulators for various purposes such as friction compensation, independent joint control, sensorless torque control and fault diagnosis. The performance of the proposed observer is demonstrated by the friction estimation and compensation for a two-link robotic manipulator. Both simulation and experimental results show the NDO works well.