CHENNAI: The Indian Space Research Organisation (ISRO) has developed a microprocessor-controlled knee for above-knee amputees. Claiming that it will help users achieve a comfortable gait, scientists said it’s ten times cheaper against imported ones. While similar imported limbs cost Rs 10 lakh to Rs 60 lakh based on the complexity of performance, ISRO’s limb is priced at nearly Rs 5 lakh.
The space agency said that their smart limb has enabled an amputee to walk about 100 metre in a corridor with minimum support and efforts are underway to improve the performance. Artificial limbs operated with microprocessors offer additional capabilities for the amputee than those offered by passive prosthetics.
The institutes involved in the project are Vikram Sarabhai Space Centre (VSSC), ISRO under an MoU with the National Institute for Locomotor Disabilities (NILD), Pt. Deendayal Upadhyaya National Institute for Persons with Physical Disabilities (Divyangjan) (PDUNIPPD-D), and the Artificial Limb Manufacturing Corporation of India (ALIMCO).
A smart limb consists of a microprocessor, hydraulic damper, load and knee angle sensors, composite knee-case, Lithium-ion battery, electrical harness, and interface elements.
The microprocessor detects the state of gait based on the sensor data. The control software estimates real-time damping needed to attain the desired gait by changing the stiffness of the system, which is further achieved by a hydraulic damper operated by a DC motor. Walking parameters specific to amputees can be set using PC-based software to improve comfort. The interface plots the parameters in real time during walking.
After testing with a normal person, the artificial limb was tested with an amputee, identified by NILD. The trials were conducted at the NILD lab in association with the VSSC. The socket and fitment of the limb were realised by the NILD. For its part, the VSSC tuned the amputee-specific parameters.
Optimisation of microprocessor-controlled limbs in terms of mass and envelope size is underway. More intelligence is also being incorporated into the system to help the amputee walk through uneven terrains with advanced features for more comfort, ISRO said.