Paraplegia means a drastic change in the life of the person affected and their social environment. From one moment to the next, you lose a large part of your independence. Climbing stairs, getting up, getting from A to B or beloved hobbies: many things are only possible with the help of others. The Swiss company TWIICE has set itself the task of giving sufferers back a large part of their independence with the help of a modular exoskeleton — it makes even ski tours possible. To ensure that the exoskeleton functions reliably under all conditions, TWIICE relies on robust connectors.
The development of a modular exoskeleton for walking support, originally intended for children and small adults, began in February 2015 at the Laboratoire de Systèmes Robotiques (LSRO) of the Swiss Federal Institute of Technology Lausanne (EPFL). “It was important for us to develop a flexible and lightweight solution that could be adapted exactly to the user’s needs. The weight of the exoskeleton was also an important issue for us: since the development was also aimed at children in particular, we wanted to make it as light as possible,” explains Dr. Tristan Vouga, co-founder and CEO at TWIICE. In the course of development, the designers realized that the modular approach had benefits well beyond the realm of a pediatric exoskeleton and its advantages were also relevant for adult patients. At 35 lbs, TWIICE’s exoskeleton is one of the lightest of its kind in the world and one of the most modular.
Modular System for Maximized Flexibility
“Loss of independence is one of many consequences of living with paraplegia. Other implications include reduction of social inclusion and of general mental well-being, but one of the most important aspects of spinal cord injury is the number of secondary health issues associated with it. From the loss of bowel and bladder management to neuropathic pain and drop in bone mineral density, there are many physiological effects that can be mitigated by the use of an exoskeleton regularly,” says Vouga.
TWIICE has motorized joints at hip level and at the knees. Soft interfaces support the upper body, thighs, and legs. By means of electric motors, the knees and hips can be bent and stretched, imitating the movements of walking. Even more complex movements such as climbing stairs can be performed. The batteries located in the back part of the exoskeleton provide the necessary energy for up to two hours of uninterrupted walking movements. Spare batteries weighing less than one kilogram per set can be carried in a separate backpack. A specific electronic system that controls the exoskeleton’s movements carries out the wearer’s instructions reliably and safely. The wearer transmits the instructions to the system via a hand control. Since every disability is unique, it was important to the engineers to develop a modular aid that can be easily customized for different users depending on their body shape and type of impairment.
“One advantage of our system is that we can also respond to the individual needs of our users thanks to its modular structure. For example, one patient was an enthusiastic ski tourer until he became paralyzed. He very much wanted to be able to do that again. As a result, our engineers developed WIITE,- a modification of TWIICE that allows you to attach ski boots to the skeleton and go ski touring,” Vouga reports. In order to be able to adapt the exoskeleton to other needs and wishes, TWIICE is working on further innovations.
To ensure that the joints do what the wearer tells them to do, reliable transmission between the controller and the joint is essential. For this purpose, TWIICE entered into close cooperation with the connectivity experts from Fischer Connectors as early as the development phase. “It was particularly important to us that the connectors are not only reliable, but also robust enough for all weather conditions and at the same time also compact enough that they can be easily inserted into the exoskeleton without sticking out. We have worked closely with Fischer Connectors from the very beginning and together we have developed solutions for our needs,” says Vouga.
The connectors establish the interconnection between the hand control and the back section. The commands that the user enters via the hand control are transmitted to the control center in the back section. From there, they are transmitted via other connectors to the knee or hip joints and the electric motors inside, and the walking movement is triggered.
For this application, Fischer recommended its LP360, part of the Fischer Freedom™ series, which are low profile, easy to mate, and fully cleanable. Since the exoskeleton is primarily used outdoors, the connectors must also withstand the elements. To ensure this, a membrane safely protects the contacts from contamination and moisture in accordance with protection class IP68. At the same time, it enables easy cleaning. Also, the handling is very user-friendly. Due to the lack of coding, the connectors have an uncomplicated 360° plug-in option. Thanks to ideal cable management, everything stays in its place and the user does not run the risk of getting tangled in the cables. The blind-mate 360° locking makes any incorrect operation impossible and the plugging process intuitive.
The connectors are also sealed according to IP68. The connectors made of chrome-plated aluminum also excel with their low weight — they are about 50 percent lighter than comparable products made of brass. This makes them ideal for mobile applications. Since the connectors can be manufactured in any size and housing shape, it was possible to adapt them precisely to TWIICE’s needs.
Second Place in the Cybathlon
TWIICE’s technology, which has proven itself in the field, was also able to convince in a sporting competition. The ETH Zurich Cybathlon is a competition for people with disabilities who, supported by state-of-the-art technical assistance systems, compete against each other in solving tasks relevant to everyday life. Beyond the competition, the Cybathlon offers a platform to advance research in the field of assistance systems suitable for everyday use. At the 2020 edition, the TWIICE team and athlete Silke Pan won the silver medal in the Powered Exoskeleton Race (EXO) discipline. The participants in this race have to complete a course as quickly as possible while wearing an exoskeleton. In doing so, they have to master everyday activities such as climbing up and down stairs, opening, passing through and then closing a door, or overcoming obstacles fixed to the ground.
Quality of Life Through Independence
Walking independently again, climbing stairs, or going ski touring. For most people living with paraplegia, this is an enormous gain in quality of life. This is possible thanks to the TWIICE exoskeleton. And the application possibilities are not fully exhausted yet.
“Our team is continuously working on new modifications to be able to offer people even more possibilities,” says Vouga. An important part of the exoskeleton are the connectors from Fischer Connectors. “We are proud that our connectors contribute to such an exciting and important innovation as the TWIICE exoskeleton. Our products help save people’s lives in many applications, and now they are also helping to improve the quality of life of paraplegics. That is really something special,” says Martin Wimmers, CEO of Fischer Connectors GmbH.
This article was written by David Ptatek, National Sales Director, Fischer Connectors, Alpharetta, GA. For more information on TWIICE, visit here . For more information on Fischer Connectors, visit here .