Designing tailor-made devices for virtual-reality based rehabilitation

Virtual Reality (VR) technology has existed for over 30 years, but in the recent years it gained popularity in various sectors. The dominant VR market is the entertainment world in particular gaming. However, due to its advantages, in particular in enhancing the visualisation experience of the user, VR is being applied in manufacturing, architecture and healthcare. Regarding the latter sector, VR is being exploited for surgical intervention training and rehabilitation. Irrespective of the application, a device, similar to the Playstation console, is required to enable users to play a ‘serious’ game in an interactive and immersive VR environment. The primary purpose of a serious game goes beyond pure entertainment, such as for a rehabilitation purpose. However, most VR-based applications use an off-the-shelf device, which for a certain category of end-users, with limited hand and finger dexterity, may not be sufficiently comfortable to use.

Within this context, a research team led by Prof. Ing. Philip Farrugia from the Department of Industrial and Manufacturing Engineering (Dime) at the University of Malta is involved in a €4m Horizon 2020 project titled Personalised recovery through a multi-user environment: Virtual reality for rehabilitation (PrimeVR2). The idea behind this project is that instead of using an off-theshelf device to play a serious game, one can use a VR device, which is purposely designed according to the person’s needs for rehabilitation purposes. The tailor-made wearable device is being developed specifically for each of three target users, namely persons who suffered a sports injury, post-stroke patients and children with dystonia. (The latter category of users experience involuntary hand movements). It is anticipated that through VR-based rehabilitation, there will be a reduction in the duration of the therapy programme. Furthermore, it is envisaged that such a technological approach will engage users more in the therapy, compared to the current traditional clinical practices.

The project commenced in October of 2019 and since then the team of international partners has worked hard to identify the key requirements for such a device. As in any other product development process, understanding the key product requirements on various levels (e.g. ergonomics, regulatory and functional) is vital to design a successful product. The main challenge encountered is how to strike a balance between meeting all the requirements of the end-users (including the therapists) and keeping the design of the controller, simple and yet competitive pricewise. Furthermore, one has to keep in mind the various regulations and standards that the product has to adhere to. With regard to the latter aspect, a cradle-tograve approach was adopted, which enabled the UM research team to identify numerous standards relevant to different life phases of the controller.

The first design iteration of the wearable device will soon be completed. The current principal role of the University of Malta is to first identify critical areas where the device design deserves attention in order to firstly avoid failures during fabrication and use and secondly to reduce the number of parts as much as possible to facilitate assembly and ultimately reduce costs. After the second design iteration, a number of tests will be conducted to simulate how the device will be used in practice. In order to achieve this, in the coming months, the engineering team at UM has to design and fabricate a number of specialised test jigs which would, for instance, subject the artefact to forces which it has to endure while it is being used. This will present considerable challenges, given that each tailor-made device has its own testing requirements, depending on the target user it has been designed for. Another consideration is the fact that these devices will be fabricated by 3D printing machines, hence the mechanical properties will be different from typical off-the-shelf artefacts, which are normally produced by mass production processes, such as plastic injection moulding.

The Covid-19 pandemic outbreak complicated matters, in particular to gather data from end-users and to access laboratories to build and test critical components of the device. On the other hand, the pandemic made the team more aware of the potential of the device for tele-rehabilitation, since it can be used from the comfort of the home under the supervision of a carer, where relevant.

The Prime-VR2 international consortium is multi-disciplinary, which includes 14 organisations in England, Scotland, Cyprus, Malta, Italy, The Netherlands, Finland, Hungary, Belgium and Ireland, comprising five universities, six SMEs and three living labs. The consortium has expertise in virtual reality, additive manufacturing, 3D geometrical form generation, user interface design, user-centred design, electronics design, systems integration and rehabilitation. The team at the University of Malta, who is working on the project consists of Prof. Ing. Philip Farrugia, Dr Ing. Pierre Vella, Ing. Emanuel Balzan and Mr Edward Abela from Dime, Faculty of Engineering, Prof. Ing. Glenn Cassar from the Department of Metallurgy and Material Engineering and Dr Maria Victoria Gauci from the Department of Disability Studies, Faculty for Social Wellbeing.

The role of the engineers is to design the aforementioned special jigs and to provide expertise on the assembly and manufacturing aspects of the device, while that of Dr Gauci is to provide feedback on how the design of the device can be improved from a therapeutic point of view. Besides the University of Malta, two other Maltese entities are involved in this project; Flying Squirrel Games Ltd, whose role is to develop the serious games environment and St James Hospital, whose role is to test the device for the sports injured end-users.

An international workshop on Design for additive manufacturing for interactive devices is planned for the first quarter of 2022. The plan is to hold the event physically in Malta during which lessons learnt from the project will be disseminated.

Further details on this project are available at www.prime-vr2.eu