Development of hybrid force-position controller for ultrasound-guided breast biopsy robotic system

• Main Author: Ayob, Mohammad Afif
• Format: Thesis
• Language: English; English; English
• Published: 2018
• Subjects: TJ210.2-211.47 Mechanical devices and figures. Automata. Ingenious mechanisms. Robots (General)
• Online Access: http://eprints.uthm.edu.my/211/

Conventional ultrasound-guided breast biopsy (UGBB) procedure is commonly performed to assess abnormal masses within the breast. It requires a radiologist to handle multiple devices at once, which could reduce the abilities in performing such procedure resulting in radiologist’s fatigue, compromised breast tissue due to multiple insertions and susceptibilities to pneumothorax complication for the patient. Previous studies have reported that many of the restrictions associated with handheld minimally invasive methods were tackled when physician assist instruments were used. Therefore, the purpose of this research is to assist radiologist in conventional UGBB procedure by introducing a semi-automated robotic system to maintain desired contact force between the ultrasound transducer and the breast. For that reason, a hybrid force/position controlled UGBB robotic system has been developed in simulation environment. The UGBB robotic system involves a 5 degree of freedom (DOF) articulated robot arm to control the transducer movement, a force/torque (F/T) sensor system to measure the contact force, an ultrasound machine to view the inside structure of the breast tissue and a computer-based control system. As such, the RV-2AJ robotic arm has been modelled with its positional accuracy of almost 100%. A breast model based on a medical grade breast phantom has been established with a mean error of 0.69% by using black-box modelling approach. Motion disturbance from human respiration has been explored as well since it plays a significant element that would affect the stability of the system to constantly maintain low contact force on the breast.Finally, intelligent Fuzzy-PID hybrid force/position controller has been successfully established to maintain low contact force on identified breast stiffness characteristics. The overall hardware-based simulation shows promising outcomes with almost no overshoot, fast rise time, high robustness and stability on different environment condition. In conclusion, the success of this work serves as significant foundations for long-term related research, especially in the development of UGBB robotic system and approaches of force control mainly for human-robot interaction.