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Flexible Skeleton takes the weight off

31 July 2015
The exoskeleton fitted to a manekin.
The exoskeleton fitted to a manekin.

Some soldiers carry in excess of 85 kg of mission-essential personal equipment. This load can cause fatigue and injury and impact a soldier’s performance.

The current generation of powered exoskeletons uses a complex system of rigid linkages and mechatronics. They are showing real promise in enabling the wearer to lift and move about with very heavy loads. 

However, the design and natural movement of the human body tends to battle with the exoskeleton movement, causing a dramatic increase in the user’s energy cost when walking with a load. These systems tend to be heavy (>35 kg), very expensive and power hungry.

DST Group researchers have developed a simple, lightweight (3 kg) fully-passive exoskeleton. This system uses Bowden cables to attach to a rigid backpack frame. The cables run down the back and legs to the base of the boot and transfer approximately two thirds of the backpack load to the ground. This load force bypasses the user’s body, reducing compression forces from the backpack load through the torso and legs. 

The benefits of such a system compared to a powered exoskeleton include: simplicity, no requirements for heavy batteries; low cost; easier to integrate with the user and equipment and redundancy when no longer required – remove and add to pack.

The development is at a proof-of-concept stage with early testing showing encouraging results. However, the biomechanics of the system require extensive refinement to ensure it is integrated optimally with the soldier and truly fit for purpose.

While the technology is being developed around use in the military, it might be applicable to many civilian scenarios such as firefighting, trekking and personal load carriage roles that require assistive technology.