Powering an exoskeleton for paraplegics

Sensor manufacturer FUTEK recently partnered with the Institute for Human and Machine Cognition (IHMC) on its latest exoskeleton, the Mina v2, which will provide paraplegics with gait mobility. These powered exoskeletons have several of FUTEK’s LCB200 load cells, which were installed in the actuators to measure the torque that the actuator applied.

Spinal cord injuries (SCI) often leave the patient with little to no ability to ever walk again. The IHMC aimed to help solve this with a powered bionic exoskeleton. The Mina v2 exoskeleton suit utilises power actuators that strap to an individual’s legs, moving their hip, knee and ankle joints and allowing an individual to walk unassisted.

FUTEK provided the exoskeleton with LCB200 load cells, which were installed in specialised fixtures attached to motors. As the motor operates, it applies force to the joint, rotating it like a human joint. This force is then measured by the load cell.

The mV/V signal from the load cell is sent to the IAA series analog amplifiers or IDA100 digitally configurable amplifier. This amplified signal is then sent to the exoskeleton’s control system, using the amplified load cell output to close the loop and drive the exoskeleton’s motors. The IDA100 amplifier output can be simultaneously monitored and adjusted on a Windows PC with FUTEK’s SENSIT software while providing high-speed, amplified, analog output.

The load cell therefore enables the system to receive force feedback from the motors and to close the control loop, minimising extraneous loads and providing accurate load data, all while allowing the sensor to safely rotate.