Thesis Format
Integrated Article
Degree
Doctor of Philosophy
Program
Biomedical Engineering
Supervisor
Patel, Rajni V.
2nd Supervisor
Kermani, Mehrdad R.
Co-Supervisor
Abstract
Recent advancements in robotics have opened new opportunities for medical applications, particularly in minimally invasive surgery (MIS) and therapeutic rehabilitation. Many studies have confirmed the benefits of robotics in surgery, leading to increased adoption of robotic solutions for medical applications and the corresponding industrial sectors. Medical robotics enhances the surgeon's dexterity, offers superior precision, improves the surgical team's ergonomics, and enables innovative procedures that are not feasible with traditional techniques. Robotic technologies have demonstrated significant potential to improve healthcare outcomes, contributing to higher patient survival rates and an enhanced quality of life.
This study encompasses a broad range of technologies and applications, including the design and development of continuum robots for MIS and haptics-enabled bilateral teleoperation systems to enhance teleoperated medical procedures. While the literature discusses various applications of tendon-driven continuum robots (TDCRs) and concentric tube robots (CTRs), several challenges remain unresolved. These include (a) the absence of control-oriented models for TDCR dynamics; (b) the lack of feasible solutions for controlling the dynamics of TDCR; (c) the fact that many CTR and TDCR designs are still at the research stage, rendering them unsuitable for clinical applications; and (d) the limited exploration of procedure-specific autonomous deployment and navigation for CTRs. Furthermore, there are several unresolved issues in the haptics domain that have not been thoroughly addressed. For instance, (a) while solutions exist to ensure the stability of delayed bilateral teleoperation, the impact of delay on transparency is often overlooked; (b) electroadhesive semi-passive actuators have been introduced for safe human-robot interactions; however, various challenges related to their development, including performance degradation, adjustability, modeling, and control, have yet to be investigated. These challenges have motivated the research presented in this study, which aims to address the gaps through novel designs, modeling techniques, and control strategies.
A part of this work presents the design of a robotic-actuated, steerable cardiac catheter, along with a novel control-oriented approach based on the deep Koopman approach to model the dynamics of the catheter, which is classified as a TDCR. The proposed method offers a globally linear model, facilitating the implementation of a task-space linear position control of the distal end of a catheter. Additionally, we explore a method for minimally invasive kidney stone removal through percutaneous nephrolithotomy (PCNL). A compact, hand-held CTR specifically engineered for PCNL has been designed and developed. We have implemented a closed-loop task-space position control of the distal end of the CTR. The effectiveness of the proposed robot has been experimentally validated using a soft abdominal phantom. Following a skin puncture, the robot autonomously navigates within the internal collecting system of the kidney to target the virtual stone based on planning using operative imaging.
The next phase of this study focuses on advancing haptics-enabled teleoperation, with the goal of enhancing transparency in bilateral teleoperation systems. A delay compensator is introduced, which decomposes the force feedback signal on the follower side using a Fourier linear combiner. The resulting decomposed weights are then used on the leader side to reconstruct the undelayed signal. Closed-loop stability of the system is ensured through the well-established passivity assumption. The proposed platform is subjected to experimental evaluation in a bilateral teleoperation setup using a rehabilitation robot and a haptics robot. Additionally, we designed and developed a rotary electroadhesive clutch for human-safe, haptics-enabled systems. The electric field is modulated using both electrical and mechanical strategies to address the issue of electroadhesion degradation. The effectiveness of the clutch is validated through haptics-based experiments that involve creating appropriate virtual environments.
The research outcomes featured various robotic technologies to enhance surgical precision, autonomy, and teleoperation clarity, setting the stage for future innovations in the field.
Summary for Lay Audience
Recent advances in robotics are revolutionizing healthcare by enabling safer, less invasive procedures and improving rehabilitation therapies. This thesis explores the development of advanced robotic systems designed to assist in medical applications, with a focus on minimally invasive interventions and remote operations enhanced by haptic (sense of touch) feedback.
One area of research described in this thesis focuses on continuum robots, which are flexible, snake-like devices that can navigate tight spaces inside the body. This thesis addresses a particular application of continuum robotics for steerable catheters and introduces innovative methods to model and control the motion of such catheters used in cardiac interventions. By leveraging a new machine-learning technique called the deep Koopman approach, the catheter can be controlled more accurately, thereby improving safety and clinical outcomes. Another significant contribution in the area of continuum robotics is the design of a hand-held concentric-tube robot for kidney stone removal. This robot helps a clinician reach kidney stones through a small incision and autonomously break down large stones, making the procedure less invasive, more effective, and safer than conventional methods.
Another major contribution of the thesis is in the area of teleoperated robotics with haptic feedback, to enable the user to control a robotic system remotely and interact with an environment (which, in the case of minimally invasive interventions, could be a patient) while the force interaction with the environment is reflected back to the user. A novel method was developed to ensure transparent remote interaction even in the presence of latency (time delays) in the communication network between the leader (user's) console and the follower robot. This significantly enhances the quality of perception during teleoperation, particularly in human-robot interaction in rehabilitation scenarios. Additionally, this study introduces an innovative clutch based on harnessing electrostatic force. The clutch is a semi-passive actuator that is lightweight and power-efficient. It provides fine-tuned force control, minimizing safety risks when a human interacts with a robot during therapy or clinical interventions.
The research described in this thesis provides novel practical approaches for robotics-based procedures that are more efficient, less invasive, more accurate, and safer.
Recommended Citation
Feizi, Navid, "Continuum Robotics, Haptics, and Teleoperation for Medical Applications" (2025). Electronic Thesis and Dissertation Repository. 10653.
https://ir.lib.uwo.ca/etd/10653