Novel 3D Printed Robotic Knee
A lightweight and energy economic Powered Knee Orthotic Device designed by IIT Kharagpur
|Jasmine Jerry A
Modern prosthetic limbs are far more superior than those developed in the last century but these new models have their limits. While assisting a patient’s natural way of walking for changing terrains, like sudden steep hills or varying surfaces, these concomitant devices become huge power guzzlers.
Powered knee orthotic device (PKOD) helps those, who have either partially or completely lost the neural ability to operate this joint due to stroke, spinal cord injury or any other reason. The goal of a PKOD is to assist the movement of the human knee joint for walking on all kinds of terrains and performing a few other daily-life activities like sit-to-stand motion. While walking, the job of the knee joint is to provide adequate stiffness in order to maintain balance in stance phase, and in the swing phase, the knee is flexed for toe clearance. The energy expenditure for these two activities increases, while encountering the up-terrains, such as stair ascent.
The issue:
The PKODs have a few complications, among which, power consumption and weight are considered to be the major ones. Researchers at the Advanced Technology Development Centre, IIT Kharagpur — Saikat Sahoo, Aditya Jain and Prof. Dilip Kumar Pratihar have developed a better and new mechanism that overcomes these challenges in this paper. They have innovated a four-bar controlled compliance actuator (FCCA).
How the system works:
In FCCA, instead of using the widely used screw transmission mechanism, a four-bar mechanism is used to modify the joint’s angular deviation and stiffness.
The results:
The input motor torque has been amplified by almost 10 times using the proposed mechanism as desired. Also, the response time is higher, achieved by just using a four-bar mechanism. A 3D-printed prototype of the proposed design has been developed, after optimizing the design parameters. Simulation and experimental analysis justified the performance of the proposed PKOD.
An energy economic yet simple design of PKOD for assisting the knee joint in daily life activities, while maintaining the weight and speed of response, as desired for the wearable applications seems like a ray of hope for the specially-abled.
What next:
A hybrid model using both metallic and 3D-printed parts would be developed after performing stress analysis and shock resistance studies. Finally, the prototype will be tested on real subjects for walking on different kinds of terrains.
This engi-knee-ring feat surely satisfies the knee-d for today’s energy-starved world! Is this too much now?
Design and Analysis of a Novel Lightweight, Energy Economic Powered Knee Orthotic Device, Saikat Sahoo, Aditya Jain, and Prof Dilip Kumar Pratihar, IIT Kharagpur
Jasmine Jerry is a third-year undergraduate pursuing Aerospace Engineering passionate about robotics and unmanned systems. She spends most of her time on soccer-playing robots or aerial vehicles. She also is a member of Lean In Chapter at IIT Kharagpur.
