Control Systems and Instrumentation Laboratory
1. Design and Development of Shape Memory Alloy based Novel Actuators for Minimally Invasive Surgeries
Prof. Amarasinghe YWR / Dr. Dayananda NWN
Most of the tools used in Minimally Invasive Surgeries are hand held slender instruments with limited degrees of freedom achieved by conventional actuation mechanisms. In this research, a Shape Memory Alloy (SMA) based approach was employed to improve the functionality of the tools.
SMAs are smart alloys which can remember a parent shape according to the heat treatment temperature and aging time applied to it, and accordingly provides unique activation temperatures. A Differential Scanning Calorimetric analysis was conducted in order to estimate transformation temperatures. Material samples were subjected to observations under Optical microscope and Scanning Electron Microscope to observe morphology and then to find out elemental composition respectively.
A Commercially available SMA material known as NiTiNOL was selected to manufacture an SMA spring actuator with the use of specially designed fixtures. The spring actuator was characterized in terms of force and stroke using a custom developed apparatus. Apparatus was controlled by a PID based multifunctional controller and the data acquisition was performed using a customized PC based Graphical User Interface (GUI).
The spring actuator was applied to a gripper mechanism and a Laparoscopic retractor tool to validate its performance. The mechanisms were validated using numerical simulation. Both the apparatuses were controlled and data were acquired though dedicated controllers and GUIs. Read more...