Robust uncalibrated visual servoing control based on disturbance observer

- A systematic design strategy is proposed with robust stability analysis.
- The problem of singularities and local minima in visual servoing control is avoided.
- External disturbances and image noises are suppressed optimally.
- Robust internal stability of the closed-loop system is ensured.

In this paper, an uncalibrated visual servoing scheme with optimal disturbance rejection performance is proposed based on disturbance observer (DOB). Comparing with traditional uncalibrated methods, which estimate online the hand-eye relationship characterized by varying image Jacobian, the uncertainty of image Jacobian is eliminated via DOB to approach a given nominal model in this paper. By solving a constrained optimization problem transformed into an H∞ control framework, the disturbance rejection performance is optimized while ensuring the robust stability of the closed-loop visual servoing system. The controller is based on the nominal image Jacobian matrix, thus avoiding singularities and local minima. Simulations and experiments show that the proposed scheme performs better in tracking an object than traditional algorithms. The disturbance and image noise rejection performance is verified.