Reveal ready.
The MARCH X exoskeleton is assembled and training has started!
On the 19th of March, 2025, we presented the design of our exoskeleton, announced our team goal and highlighted the innovations made this year!
After the Design Presentation, we assembled our exoskeleton and started training for the Reveal with our pilot Daan.
Join us at our Exoskeleton Reveal on the 17th of July in Tivoli Vredenburg to see our design in action, in real life!
Team Goal
Project MARCH X will build an exoskeleton that enables the pilot to attend a standing concert by standing self-balanced while resisting external disturbances, and by walking more naturally to decrease physical effort by the end of July 2025.
Coupled Linears
For our goal of withstanding side disturbances, we need the exoskeleton to actively counteract the force to remain balanced.
To achieve this, we are introducing an additional linear joint at the ankle. But since space around the ankle is very limited, we had to come up with a compact yet efficient design. So, rather than just adding another linear to the ankle assembly we decided to create two linear joints that work together in a coordinated way, placed on the side of the foot.
With the two motorized linear joints at the ankle, we are now able to actively counteract forces from the disturbances, enhancing stability and control.
Model Predictive Control
This year we are deploying a Model Predictive Control algorithm on our exoskeleton. This algorithm enables our exoskeleton to anticipate movements and react in real time.
Design
Motor controllers (MDrives)
To actually move the exoskeleton, the computer sends precise motor commands to our custom made motor controller: the MDrive!
Our MDrives drive the motors and assure that the joints move exactly as instructed by the computer. The speed and complexity required for our balancing goal, not only asks more from our computer, but also from our MDrives.
For this reason we have upgraded to a larger and more powerful microcontroller chip.
Inertial Measurement Unit (IMU)
This year we are introducing a sensor on the MDrive: an inertial measurement unit, or IMU for short.
The IMU, determines rotation and acceleration in 3 dimensions These IMU’s are positioned on every MDrive, and the MDrives are positioned all throughout the exoskeleton. This means that we can determine the orientation and acceleration of different segments in the exoskeleton at 5 different locations; two in each leg and one in the backpack.
This brings us actually to a total of 45 sensors throughout the exoskeleton!
Redesigned pressure soles
This year marks the return of the pressure soles, because they are essential for our balancing goal. This year, we have completely redesigned the pressure soles. We are now making use of 4 load-cells per foot.
Each load-cell is their own force sensor used to determine the exerted force by the exoskeleton on the ground. With 4 load-cells per foot, we can precisely determine the so-called Centre of Pressure of the exoskeleton. The Centre of Pressure can be seen as the average location of all of the forces exerted on the ground or as a balance point.
Input Device
Through our own custom made input device, Daan can intuitively select what he wants the exoskeleton to do.
This input device, which can be placed on the crutches, consists of multiple buttons that allows Daan to choose between different movements of the exoskeleton.
With just a press of a button, the pilot’s intentions are registered. Daan gets confirmation of his choice with visual and haptic feedback from the controller.
Depth cameras?
Torque control
To ensure precise control and stability, we also need sensors to provide continuous feedback.
In our exoskeleton, we are recreating this feedback system, with a new custom designed torque sensor. This sensor will be integrated in the rotational joint. This joint replicates the flexion and extension of the knee and hip.
Just as muscle spindles detect external forces and trigger a response, the torque sensor measures forces within the joint. These signals are then sent to the computer, which then adjust the motor of the rotational joint to keep the exoskeleton balanced.
By continuously sensing and reacting to these forces, the exoskeleton can maintain stability and enhance safety.