SHAPE MEMORY ALLOY ACTUATOR CONTROL FOR 3D STEERING OF ACTIVE SURGICAL NEEDLE IN MINIMAL INVASIVE SURGERIES

Abstract

Minimally Invasive Surgery (MIS) is defined as a surgical procedure that is associated with lower postoperative patient’s morbidity, compared to the conventional approach for the same diagnostic/therapeutic operation. Minimally invasive percutaneous interventional procedures for diagnostics and therapeutics are practiced in a variety of medical procedures such as brachytherapy, biopsy, and thermal ablation. The clinical outcome in such procedures is subjected to precise navigation and accurate placement of the needle at specific target locations within the soft tissue. Active needle steering increases the target placement accuracy, and consequently improves the clinical outcome. In this work, a 3D steerable active flexible needle with multiple interacting Shape Memory Alloy (SMA)-wire actuators is introduced. A self-sensing resistive-based feedback loop control system was designed and implemented to control the SMA’s actuation. The needle tip position was controlled through the feedback loop control system using the electrical resistance measurements of the SMA-wire actuators. Concomitant actuation and sensing capabilities of SMAs were used in the control system to realize a desired 3D motion at the needle tip. The controller was then tested on a 1:4 scaled prototype of the active needle for reference path tracking. This work demonstrates the 3D steerable active needle manipulation via precision control of interacting SMA-wire actuators.