An Improved High-Gain Observer Design for Flexible Needle Steering

Abstract

In the robot-assisted puncture surgery, the posture of the needle tip may not be available directly owing to the small dimension of the needle tip and the existence of measurement noise. On the other hand, the existing high-gain observers are robust against model uncertainty but sensitive to measurement noise. The peaking phenomenon is also a typical problem when applying those high-gain observers. Aiming at these issues, an improved high-gain observer is devised to observe the pose of the needle tip in this paper. To reduce the effect of the measurement noise and the peaking phenomenon, the power of observer gain is designed as 2 by extending the observer degree and a correction term of measurement estimation is added to improve the property of the observer against the measurement noise. Finally, the performance of the proposed observer is verified via a simulation example.