A shared-control ultrasound-guided robotic system for liver puncture under respiratory motion

Ultrasound (US)-guided liver puncture is widely used in diagnosis and minimally invasive intervention. However, the procedure is highly dependent on the surgeon's experience and is substantially affected by respiratory motion (RM), which can reduce imaging stability and puncture accuracy. To address these challenges, this paper presents a shared-control robotic system for US-guided liver puncture under RM. The proposed system integrates a puncture execution mechanism (PEM) that enables coordinated US probe manipulation and needle operation while preserving the surgeon's control over needle orientation and insertion. To improve procedural stability, a dual-stage pose-force assistance strategy is developed. In the first stage, pose-guided assistance is used to position the US probe and obtain a suitable imaging view. In the second stage, force-regulated interaction control is applied to maintain stable probe-skin contact during RM, while the surgeon remains responsible for the puncture action. In addition, a bionic respiratory motion device (BRMD) was developed to simulate thoracoabdominal anatomy and RM using medical-imaging-compatible anthropomorphic phantoms. In phantom experiments, the proposed shared-control system reduced the average operation time, decreased the puncture RMS error, and increased the success rate compared with manual operation. An in vivo study in a Labrador dog was further conducted as a feasibility demonstration.