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Project MARCH VII is one of the student Dreamteams of the Technical University Delft. Each year a group of 26 motivated students puts their study on hold for a whole year to design and develop an exoskeleton. An exoskeleton is a robotic suit that provides support, allowing someone with a spinal cord injury to get back up and walk again. We design the exoskeleton in co-creation with our 27th and most important team member, our pilot Koen. Koen has a spinal cord injury and is wheelchair-bound in day-to-day life.
The vision of Project MARCH is that technology can improve the quality of life for people with spinal cord injuries. We want to accomplish this by designing a better exoskeleton each year. An exoskeleton gives people with a spinal cord injury the freedom of movement back and helps improve their health significantly, both physically and mentally.
Last year, huge steps were made to make the exoskeleton more adaptable to daily life by taking the exoskeleton outside. The environment and surfaces outside are unpredictable. So, the exoskeleton needs to be aware of its surroundings. This year, Project MARCH VII aims to take it even further by building a so-called ‘smart’ exoskeleton. We want the exoskeleton to see its surroundings and react to them by stepping on the right spots and giving suggestions to the pilot.
Because our goal this year is walking while generating walking patterns on the fly, we need the exoskeleton to be able to somehow detect when it is standing on the ground. Our Electrical Engineers have been researching how to make this system possible. We do this by using a type of force sensor called a “pressure sole”, which is placed in the sole of the shoe. These sensors change their internal resistance based on how much force is put on them. We can detect a small part of the wide range of the possible force it could possibly readout, which in turn will be sent as usable data. Another goal for Electrical is to improve the quality and reliability of the systems that are already used. We want to make sure that what is promised is actually done working.
This year, we want the batteries to provide just the right amount of power that we need. So the battery has the most efficient size. The amount of power the batteries can deliver depends on the number of cells and the configuration. In our case, we will use 15 cells connected in series, which will ensure the 48V needed for the operation of the motors. Furthermore, we take into consideration the overall layout of the electronics in the backpack of the exoskeleton while designing the placement of the cells into the battery pack. We do this in close collaboration with our Design Engineers. So everything fits nicely and is easily accessible.
Power Distribution Board
All power supplied by our battery I would say “is distributed to the electronics in the exoskeleton through the Power Distribution Board (PDB). The design of the PDB of Project MARCH VII contains new features and improvements to the existing ones. For example, we implemented a temperature sensor on the PDB to measure the ambient temperature in the backpack. This way the speed of the fans in the backpack can be controlled depending on this temperature. Moreover, an SD card was added so that all the data can be collected without being lost due to an unexpected failure, which makes troubleshooting easier. As for the improvements, the feature to turn the exoskeleton on and off was redesigned as well as other connections that proved useless were removed. Finally, the connectors’ placement on the PDB was changed for better cable management.
Since the start of our year, we’ve worked extensively. Our digital design for the new exoskeleton, the MARCH VII is finally ready! Now that the digital design is done, we will start producing the physical components. Our Electrical Engineers receive valuable help from Eurocircuits in terms of producing our PCBs.