Tele-micromanipulation of Electrothermally Actuated Robotic Fibre for Precise Medical Applications

Surgical approaches for tumour resection aim to minimise the sacrifice of healthy tissue while ensuring complete removal of the tumours to avoid recurrence. This is particularly challenging in minimally invasive surgery (MIS). Miniaturized and precise robotic instruments that can manipulate diagnostic or therapeutic tools allow superior access and enhance the accuracy of these surgeries. In this context, several fibre-based robots have been developed [1,2]. In our previous work, we have developed an electrothermally actuated robotic fibre. The fibre’s actuation is achieved by differential thermal expansion across the fibre’s cross-section, induced by Joule heating (Fig. 1a). This robotic fibre enables the precise delivery and manipulation of surgical tools like laser fibres [3]. Our published work [3] has well-documented the analyses of its dynamic behaviour, mechanical, and thermal properties. The comparison with state-of-the-art actuators also highlights the contributions of our robot in terms of precision (<50μm), dimensions (<2mm), motion range (<6mm), maximum velocity (10.3mm/s), and simplicity of the actuation unit [3]. In this work, we developed a telemanipulation controller that allows the operator to control the robotic fibre with a joystick manually. To demonstrate and evaluate the motion precision of this robotic system, we designed a micro-manipulation task. We utilised the robotic fibre to hold and manipulate a bespoke electromagnet coil to grab and move a magnetic particle along a small maze with a tortuous path. A longer fibre was designed and inserted through a da Vinci instrument to improve the precision of the surgery. Considering that only the fibre distal end needs to be actuated, a partial actuation approach would benefit the patient's safety and energy consumption. In the second part of this work, we introduce a new approach enabling actuation and control of the 12-centimetre distal end of a 1.2-metre-long fibre robot. The assembled robotic system was tested in an abdominal phantom, validating the concept of integrating robotic fibres with commercially available endoscopic devices.