Project MARCH IV – Update

September 2019

Introduction

4 years ago, a couple of students from the Delft University of Technology got inspired by a big international competition.

A competition called ‘The Cybathlon’, where physically disabled people compete against each other in everyday tasks with the help of technical systems.

One discipline is meant for paraplegics who are wheelchair bound.

With the use of an exoskeleton, which is a motorised robotic harness, they are able to stand and walk again.

During the race they have to complete daily life obstacles for wheelchair bound people like stairs, slopes or tilted path.

The Cybathlon tries to stimulate innovation by making the obstacles more difficult every year.

To win the Cybathlon, you have to complete all the obstacles and you have to be the fastest.

So these inspired students started this student team from the Delft University of Technology that designs and builds a new exoskeleton every academic year.

They named this student team Project MARCH.

Project MARCH works in a yearly cycle and every year a new team starts and at the end of the year a new exoskeleton has been developed.

Now, four years later, four teams have started and four MARCH prototype exoskeletons have been build.

Every academic year, the new team tries to improve and optimize the prototype of the year before.

All Project MARCH teams aim for the same goal: to win the Cybathlon.

In August 2018 we, a group of 23 students, started as the MARCH IV team.

Meet the Team

Back then, we were still searching for our pilot: a paraplegic that will be in control of our MARCH IV exoskeleton.

A few weeks later Sjaan Quirijns agreed to be a part of our team.

She is a very important team member, because Sjaan can tell us what the user may like or may not like about a design.

On top of that, Sjaan will compete in our MARCH IV exoskeleton against other exoskeletons during the Cyabthlon Experience on September 20 in Rapperswil, Switserland.

After months of brainstorming, devising concepts, testing concepts, making detailed designs, assembling and training we are ready for the ultimate test!

The MARCH IV Exoskeleton

What is this MARCH IV exoskeleton capable of?

Simply said, the MARCH IV exoskeleton contains four different types of joints on each side.

One hip joint and one knee joint that make it possible to move the legs forward.

That way, Sjaan is able to walk straight ahead.

Another hip joint makes it possible to move the legs lateral which is needed for taking a step to the side.

The ankle joint makes sure that the feet can bend upwards and downwards.

This ankle movement is for example convenient when walking up or down a slope compared to flat ground.

Sjaan controls our exoskeleton with the input device which is located in the crutch.

The input device consists of a screen and buttons that allows you to select the movement you want to make.

For example walking or sitting down.

Some important improvements this year compared to the prototypes of the years before, are the hip joints.

These can now move sideways.

In addition a large software update and pressure soles that now make research into balance possible.

MARCH IV is the first MARCH exoskeleton where lateral movement of the hip is possible.

The addition of this joint provides more degrees of freedom.

In the near future, the hip will help during an obstacle of the Cybathlon in which the exoskeleton has to walk on a tilted path.

In the long term, this new hip joint could help to make walking with the exoskeleton feel more stable and natural.

The pressure sensors, that can be found in the soles of the feet, measure how the exoskeleton stands on the ground with the user in it.

This way, data is collected that can be used to conduct research into the balance of the exoskeleton.

Another place where sensors can be found that can contribute to the future balance of the exoskeleton is the upper body of the user.

Here, sensors are placed that measure the position of the upper body.

This information can ultimately help to better determine the movement of the user with the exoskeleton.

In the longer term, this can contribute to an important wish of users: an exoskeleton where the crutches are no longer needed.

In the new software of the MARCH IV exoskeleton, modularity is included.

Modularity has been applied here in order to be able to continue to use the current software in the coming years.

Software is often completely discarded when it is no longer understandable or usable.

By applying modularity to the software, you can turn one complex system into divided building blocks.

This allows teams to easily add, replace or dispose of software blocks in the coming years. It is therefore no longer necessary to start all over again if an important change needs to be made.

A new improvement related to the electronics of the MARCH IV, which through the support of Eurocicruits has become a reality, is about our long term goal of reducing the weight and size of the exoskeleton.

That way, the exoskeleton will become easier to transport and to carry around. In the MARCH IV, we have been working on achieving this goal.

For example, the hip structure has almost double the amount of electronics compared to the previous model because of the new hip joint.

This makes the electronics an important limitation for reducing the size of the exoskeleton. In order to be able to take steps, there are two solutions that we have used in the MARCH IV.

The first is to replace the functionality of the electronics with software.

The second solution is to make the electronics smaller and more efficient. A good example of this is the Power Distribution Board (PDB).

The PDB is the electronics that distributes all the energy over the entire exoskeleton.

By using smaller components and using both sides of the board, the surface area of the PDB is reduced by 20% and it is also a lot flatter compared to its predecessor.

For more information about the electronics in our MARCH IV exoskeleton, read our previous blog!

With these new improvements, we will be attending the Cybalthon Experience in Rapperswil on September 20.

The following year, the fifth team of Project MARCH will work on the our fourth exoskeleton to improve it in the run-up to the big Cybathlon in May 2020.

For this race already 15 exoskeleton teams have signed up to compete for the title of best exoskeleton of the world.