Browsing by Author "Wijethunge, D"

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item: Article-Full-text
Design and development of a novel oral care simulator for the training of nurses
(IEE, 2020) Herath, B; Dewmin, GHS; Sukumaran, S; Amarasinghe, YWR; De Silva, AHTE; Mitani, A; Wijethunge, D; Sampath, WHP
Objective: A Novel Oral Care Simulator was designed and developed to measure and visualise the facial and lingual forces exerted on teeth by the action of tooth brushing, considering the irregular geometry and structural composition of human dentition and the emulation of the realistic biomechanical deflection of the teeth. Method: FEA simulations were carried out on a central incisor under facial loading and an appropriate force sensing mechanism was designed. An anatomically accurate mandibular jaw and 16 teeth were 3D printed, on which 16 force sensing structures were embedded. The signals from the sensors were amplified using a multichannel signal amplifier built using instrumentation amplifiers which were then visualised through a GUI. Results: The developed simulator is capable of indicating the magnitude of a force upto 15 N exerted on to the facial and lingual surfaces of teeth at a frequency of 60 Hz and above and it is capable of alerting the user if the force exceeds a pre-specified threshold. Conclusion: The designed force sensing mechanism considers the irregular geometry and structural composition of human dentition in measuring the facial and lingual forces. It provides a reliable feedback by indicating the force and emulating the realistic biomechanical deflection of teeth. Significance: Nurses who care for the disabled, elderly and sick have explicitly stated the requirement for a simulator to train themselves on brushing the teeth of their subjects as their incorrect technique can cause longterm dental damage, for which a device has not been developed to date.
item: Conference-Full-text
Development of a pid based closed loop controller for shape memory alloy actuators
(IEEE, 2018-05) Roshan, TAU; Basnayake, BADJCK; Amarasinghe, YWR; Wijethunge, D; Nanayakkara, ND
Shape Memory Alloy (SMA) spring actuator was designed and fabricated using commercially available NiTiNOL material by shape setting with the use of a special fixture. So, before applying the actuator to an application, a force characterization was conducted and force variation respect to uncontrolled temperature was analyzed. Due to the difference between force and temperature sensor’s response time, a lag can occur between force and temperature measurements. Therefore, a more controlled technique was further implemented by developing a Proportional-Integral-Derivative (PID) based closed loop controller, together with a Graphical User Interface (GUI) which supports parameter control and sensor calibration. Finally, a force feedback controlling method also developed using the same PID technique for a force sensitive applications, where controlled forces need to be maintained by varying temperature of SMA accordingly.