Robotic exoskeletons made for humans may look different depending on the functions they serve. Exoskeletons can be made from materials such as carbon fiber, metal, and elastic. Their coverage also varies from the entire body, to lower or upper extremities, or to a specific body part like the shoulder, hip, or ankle. Some exoskeletons have adjustable hardware so they can be tailored to the individual that is using them. Overall, the technology behind the exoskeleton depends largely on its type and function.
There are two types of exoskeletons: powered and passive.
Powered exoskeletons are equipped with electronics that register how much force is being applied to any given action, allowing the exoskeleton to share some of that burden with the user. In order for the exoskeleton to work properly, there must be technologies to support the three modules: sense, decision, and execution. These technologies include sensors, actuators, mechanical structures, algorithms, and control strategies that gather necessary information for carrying out each action. It may sound complicated, but it’s actually fairly straightforward. There are three basic steps that accompany the three modules.
- The sense module is where the information gathering takes place. The exoskeleton records data from the user via the device sensors.
- Next, the decision module interprets that data and sorts it into the intended activities.
- Finally, the execution module provides the mechanical power to complete the task.
Examples of the lower-extremity powered exoskeleton at Ekso Bionics:
This feature allows the user to view session-specific walking time, distance, and speed. It also securely saves this information into a cloud-based dashboard for easier analytics.
This feature allows the clinician to set certain parameters they can use to help better assist their patient, ushc as training targets and step parameters.
This feature allows the clinician to customize motor support independently on each leg for various impairment levels, from full assistance to patient-initiated movement, in both swing and stance phases of walking.
This feature consists of sensors and software continuously monitoring and regulating leg movement to minimize compensatory gait patterns.
The feature possesses a program suite called preGait that consists of programs that help patients balance, weight shift, squat, and step in place before walking.
To contrast with the lower-extremity exoskeleton, here are the features of the upper-extremity exoskeleton vest for construction at Ekso Bionics:
The exoskeleton vest was built with a patented stacked-link structure that seamlessly follows the user’s arm and elbow through the full range of motion while providing proper joint alignment through repetitive movement.
- Extreme logistics positions
These positions include reaching directly overhead, across the body, or even into a back pocket for a phone — are unrestricted with this wearable exoskeleton.
- Adjustable, high-force actuators
These actuators are proven to be extremely durable with over a million cycles before requiring replacement.
- Customized Assistance Levels
The level of each device can be adjusted for the user and task by easily swapping out the set of compact gas springs. Different levels can even be selected for each arm independently depending on the task.
Passive exoskeletons are purely mechanical, providing support using pulleys, a spring balancer, and weights to counterbalance the workload. Passive systems generally take the weight off the user’s shoulders and arms and transfer it to their center of gravity so that the user obtains increased endurance during overhead tasks and other demanding work.
Exoskeleton technology not only helps the individual perform tasks that directly aid in increasing mobility, but also provides medical professionals with the information needed to offer treatment with a higher chance of success. For patients with a low likelihood of regaining their mobility, these machines can be a saving grace, in many cases enabling full rehabilitation.