How does an exoskeleton actually work?

Springs, motors, cables: three very different mechanisms hide behind the word "exoskeleton". A simple explanation, with examples from our catalogue.

Introduction: one word, three mechanisms

"Exoskeleton" does not describe a single technology: the word covers at least three very different working principles, which differ in weight, price and use. Knowing which one you are looking at avoids a lot of confusion when choosing.

Chapter 1: the spring, which stores and releases energy

A passive exoskeleton, such as the Ski-Mojo or the Hapo range, has no motor and no battery. It relies on leaf springs: when the joint bends, the spring compresses and stores energy; when it straightens, that energy is released to ease the movement. Range is unlimited since there is nothing to charge, but the assistance is tied to one specific movement (knee flexion for skiing, bending forward for a Hapo back model).

Chapter 2: the motor and sensors, which add energy

An active exoskeleton, such as the Hypershell, Dnsys or VIGX models, carries an electric motor and a battery. Sensors (acceleration, position, sometimes pressure) analyse your gait several hundred times per second to adjust the assistance in real time. This type of device genuinely adds force, but it is heavier, costs more and depends on a battery that needs charging.

Chapter 3: the cable, which guides without adding force

A third family is neither spring nor motor: cable support garments, such as the Stoko K1 tights. A network of high-strength cables built into the fabric creates support around the joint, adjustable with dials. There is no energy return and no added force: the principle is to guide and stabilise, not to propel.

Chapter 4: how to choose according to the mechanism

You want walking assistance on climbs: an active motorised model is needed; a spring is not enough for this movement.
You want to relieve a repetitive movement at work or when skiing: a passive spring model is suitable, with no charging constraints.
You are looking for discreet everyday support: a cable garment is worn like ordinary clothing.

Frequently asked questions

Is a spring exoskeleton less effective than a motorised model?

It is not less effective, it is different: the spring returns energy the wearer produced, while the motor adds energy. The right choice depends on the movement to relieve, not on an absolute ranking.

Can several mechanisms be combined?

Yes: some manufacturers offer add-on modules, for example motorised hip assistance combined with a knee module, as Dnsys does.

Does the mechanism affect the price?

Generally yes: a motorised model, with its sensors and battery, costs more than a passive spring model or a cable garment, as explained in our article on prices.