User Story Wireless Motion Trackers
User story Xsens
Project MARCH is a student team of the Delft University of Technology in the Netherlands that is developing an innovative and versatile exoskeleton, which is a motorized robotic armor that can be used to let people with a spinal cord injury stand up and walk again. At this moment, the biomedical technology regarding exoskeletons is underdeveloped, so that people with paralyzed or malfunctioning legs are bound to wheelchairs for the rest of their lives. Project MARCH wants to change this!
Project MARCH is a non-profit team currently consisting of twenty-three students, of all sorts of disciplines and studies, including Industrial Design Engineering, Biomedical Engineering, Mechanical Engineering, Electrical Engineering, Software Engineering, etc. The team consists of students from different academic years and they are working voluntarily on the project for one year to design an exoskeleton, learn a lot and to contribute to society.
Project MARCH has one very special team member: the pilot. This is the person with a Spinal Cord Injury that is in control over the exoskeleton. The team works in close collaboration with the pilot to develop a user-friendly exoskeleton. This is called: co-creation.
The vision of Project MARCH is to give back mobility to physically disabled people who have been paralyzed due to illness or an accident, causing them to be bound to a wheelchair for the rest of their lives with all its inconveniences. Simple daily activities such as doing groceries, walking the stairs or going to the toilet are often challenging or even impossible for them. By giving back more freedom of movement, the paraplegic will be independent and he or she will also be able to communicate at eye-level with friends and family again. In addition, the paraplegic’s health improves significantly by using an exoskeleton. Their bones and muscles become stronger, the risk of thrombosis decreases, the bowel function improves and they experience less pain in their back.
A new exoskeleton each year
Each academic year, a new Project MARCH-team builds a whole new exoskeleton. The first exoskeleton, the MARCH I, was built in 2016. After this first exoskeleton, a second and a third were made in the following years. The fourth prototype, the MARCH IV, is made this year. Every team documents their design choices, project progress, the way of handling problems and all other things that might occur during the academic year so that new teams can continue with all knowledge and experience that is already acquired. This transition is very valuable since Project MARCH thinks it is important that every new team is able to come as far as possible with regard to designing and implementation of new technologies.
Xsens in the MARCH IV
One of the biggest limitations to our exoskeleton is that the pilot operating it still needs crutches to keep balance. The mobility the exoskeleton provides is therefore limited due to the fact that operating it is very heavy on the pilot’s arms and the pilot needing a lot of focus to keep balance.
That is why it is one of the main focus points of the MARCH IV team to do research in how the stability of the exoskeleton can be become better so that hopefully crutches don’t have to be used anymore in the near future.
Providing more stability for the pilot also means gathering more data of the stability of the pilot in the exoskeleton. This is where Xsens comes in. We chose to go with the MTw Awinda to gather data of the configuration of our combined system of pilot and exoskeleton. The encoders of our joints provide us the configuration of the exoskeleton itself and Mtw Awinda’s in the backpack and on the upperbody of the pilot provide us the configuration of the pilot with respect to the exoskeleton suit.
Knowing this configuration, we can then calculate the estimated Center of Mass (CoM) of our system. The CoM is an important parameter in the determination of stability of the system.
This information about the CoM will be used as feedback to the pilot and eventually as input to our control algorithm governing the stability of the exoskeleton.