Real-Time Robotic Force Control for Automation of Ultrasound Scanning

Ablation represents a minimally invasive option for liver cancer treatment, commonly guided by imaging techniques such as ultrasound. Recently, there has been a surge in interest in semi-automated or fully automated robotic image acquisition. Specifically, there is a continuing interest in automating medical ultrasound image acquisition due to ultrasound being widely used, having a lower cost, and being more portable than other imaging modalities. This study explores automated robot-assisted ultrasound imaging for liver ablation procedures. The study proposed utilizing a collaborative robot arm from Universal Robots (UR), which has gained popularity across various medical applications. A robotic real-time force control system was designed and demonstrated to regulate the contact force exerted by the robot on the surface of a torso phantom, ensuring optimal contact during ultrasound imaging. The Robot Operating System (ROS) and the UR Real-Time Data Exchange (UR-RTDE) interface were employed to control the robot. The findings indicate that the contact force can be maintained around a set desired value of 9N. However, deviations occur due to residual forces from acceleration when the probe is not in contact with the phantom. These results provide a foundation for further advancements in the automation of ultrasound scanning.