Development of an assistive soft exoskeleton : a multistakeholder endeavour

Background As in other areas, digitalization and new technologies become increasingly relevant for physiotherapy. However, often these developments are driven by technological feasibility rather than by clinical demand. In order to grant maximum acceptability and effective implementation of a technology multiple stakeholders i.e. engineers, patients and therapists need to collaborate throughout the planning and development processes. Here, we describe the design and development of three prototype-generations of a soft and modular exoskeleton. Purpose Development of a soft and modular exoskeleton, which incorporates the needs and requirements of future users. Methods Nine research groups including therapists, designers and engineers from seven European countries were involved in this project. As stakeholders we considered patients with gait limitations due to stroke, incomplete spinal cord injury or age-related weakness (primary end-users, PU), therapists with professional experience in the area of the PU’s conditions and non-professional carers (secondary end-users, SU). The perspectives of PU and SU were incorporated into the technical concepts adopting a user-centered design approach. The initial prototype was designed according to the requirements, which were derived from use-cases representing the target populations. Evaluations of all prototypes were performed using semi-structured interviews with both, PU and SU. Functions of the respective prototypes were evaluated with a predefined testing protocol. The conclusions of the evaluations were fed back to the engineers and informed the development of the consecutive prototypes. All data collection procedures were approved by the local ethics committee and participants provided written informed consent. Results In total eight PU and eight SU were recruited. In general, the prototypes were in an early stage of development and the operation required staff with engineering knowledge and an experimental laboratory. In general, PU and SU rated the technology positively. The individually analyzed data from the interviews and functionality tests revealed heterogeneous results indicating the diversity of the PU’s functional impairments and expectations of PU and SU. Conclusions Based on this project’s experience, we are convinced that future PU and SU of a technology must be involved in the development from the very beginning. However, in order to obtain adequate feedback, the choice of individuals (PU and SU) and the level of involvement must be considered carefully. For example, inadequate expectations may draw the attention to irrelevant issues. In our project, research physiotherapists played a key role by bridging PU and SU with engineers. This information exchange was partially challenging because of different areas of interest, different terminology and geographical distance. Implications A common understanding of the project goals among the project teams and adherence to timelines are essential for successful progress such a large project. The project should assure that all stakeholders can acquire basic knowledge and perspectives of the other involved stakeholders, especially from other disciplines. Specifically for physiotherapists, basic and continuing education should incorporate technological knowledge from engineering disciplines in order to enable physiotherapists to contribute to the development of new devices. This opens the chance to participate in the development of technology for clinical applications. Funding acknowledgements This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 688175 (XoSoft)

Basic functionality of a prototype wearable assistive soft exoskeleton for people with gait impairments : a case study

XoSoft is a soft modular wearable assistive exoskeleton for peo- ple with mild to moderate gait impairments. It is currently being developed by a European Consortium (www.xosoft.eu) and aims to provide tailored and active lower limb support during ambu- lation. During development, user-centered design principles were followed in parallel with the aim of providing functional support during gait. A prototype was developed and was tested for practi- cability, usability, comfort and assistive function (summarized as basic functionality) with a potential end user. The prototype con- sisted of a garment, electromagnetic clutch-controlled elastic bands supporting knee- and hip flexion and a backpack containing the sensor and actuator control of the system. The participant had ex- perienced a stroke and presented with unilateral impairment of the lower and upper extremities. In testing, he donned and doffed the prototype independently as far as possible, and performed walk- ing trials with the system in both active (powered on) and pas- sive (powered off) modes. Afterwards, the participant rated the perceived pressure and various elements of usability. Results high- lighted aspects of the system for improvement during future phases of XoSoft development, and also identified useful aspects of proto- type design to be maintained. The basic functionality of XoSoft could be assumed as satisfactory given that it was the first version of a working prototype. The study highlights the benefits of this participatory evaluation design approach in assistive soft robotics development

An active back-support exoskeleton to reduce spinal loads: actuation and control strategies

Wearable exoskeletons promise to make an impact on many people by substituting or complementing human capabilities. There has been increasing interest in using these devices to reduce the physical loads and the risk of musculoskeletal disorders for industrial workers. The interest is reflected by a rapidly expanding landscape of research prototypes as well as commercially available solutions. The potential of active exoskeletons to reduce the physical loads is considered to be greater compared to passive ones, but their present use and diffusion is still limited. This thesis aims at exploring and addressing two key technological challenges to advance the development of active exoskeletons, namely actuators and control strategies, with focus on their adoption outside laboratory settings and in real-life applications. The research work is specifically applied to a back-support exoskeleton designed to assist repeated manual handling of heavy objects. However, an attempt is made to generalise the findings to a broader range of applications. Actuators are the defining component of active exoskeletons. The greater the required forces and performance, the heavier and more expensive actuators become. The design rationale for a parallel-elastic actuator (PEA) is proposed to make better use of the motor operating range in the target task, characterized by asymmetrical torque requirements (i.e. large static loads). This leads to improved dynamic performance as captured by the proposed simplified model and measures, which are associated to user comfort and are thus considered to promote user acceptance in the workplace. The superior versatility of active exoskeletons lies in their potential to adapt to varying task conditions and to implement different assistive strategies for different tasks. In this respect, an open challenge is represented by the compromise between minimally obtrusive, cost-effective hardware interfaces and extracting meaningful information on user intent resulting in intuitive use. This thesis attempts to exploit the versatility of the active back-support exoskeleton by exploring the implementation of different assistive strategies. The strategies use combinations of user posture and muscular activity to modulate the forces generated by the exoskeleton. The adoption of exoskeletons in the workplace is encouraged first of all by evidence of their physical effectiveness. The thesis thus complements the core contributions with a description of the methods for the biomechanical validation. The preliminary findings are in line with previous literature on comparable devices and encourage further work on the technical development as well as on more accurate and specific validation

Back and shoulder exoskeletons for occupational use: a review

Work-related musculoskeletal disorders (MSDs) account for a large portion of all work-related injuries according to OSHA. Back and shoulder-related disorders make the most of work-related MSDs according to the Bureau of Labor Statistics (BLS). Exoskeletons emerged in recent years with the potential to reduce the risks of work-related musculoskeletal disorders and injuries. Their use in occupational settings is increasing, and exoskeleton designs are rapidly evolving. This paper reviewed recent scientific articles (2015 and after) that evaluated back and shoulder-support passive industrial exoskeletons. The findings of these articles are summarized and analyzed to assess the benefits of passive upper-body exoskeletons by identifying agreements and disagreements through these articles. Seven BSEs (back support exoskeleton) through 16 articles and eight SSEs (shoulder support exoskeleton) through 14 articles are reviewed. It is concluded through these articles that passive upper body exoskeletons can provide benefits with selected short-term manual handling tasks in industry settings. The benefits are more pronounced with quantitative assessments. Scientific studies aim to gather further data such as metabolic cost, oxygen consumption, and heart rate along with muscle load assessments to present clearer and more complete results. However, there is not enough data through the recent articles to make any clear conclusions about exoskeletons’ benefits in real-life working conditions for long term uses. Benefits can change with the design and task dramatically. However, none of these exoskeletons have presented a clear superiority to each other in these studies. Specifics of tasks and conditions should be considered to determine the most suitable exoskeleton

The-state-of-the-art of soft robotics to assist mobility: a review of physiotherapist and patient identified limitations of current lower-limb exoskeletons and the potential soft-robotic solutions

Background: Soft, wearable, powered exoskeletons are novel devices that may assist rehabilitation, allowing users to walk further or carry out activities of daily living. However, soft robotic exoskeletons, and the more commonly used rigid exoskeletons, are not widely adopted clinically. The available evidence highlights a disconnect between the needs of exoskeleton users and the engineers designing devices. This review aimed to explore the literature on physiotherapist and patient perspectives of the longer-standing, and therefore greater evidenced, rigid exoskeleton limitations. It then offered potential solutions to these limitations, including soft robotics, from an engineering standpoint. Methods: A state-of-the-art review was carried out which included both qualitative and quantitative research papers regarding patient and/or physiotherapist perspectives of rigid exoskeletons. Papers were themed and themes formed the review’s framework. Results: Six main themes regarding the limitations of soft exoskeletons were important to physiotherapists and patients: safety; a one-size-fits approach; ease of device use; weight and placement of device; cost of device; and, specific to patients only, appearance of the device. Potential soft-robotics solutions to address these limitations were offered, including compliant actuators, sensors, suit attachments fitting to user’s body, and the use of control algorithms. Conclusions: It is evident that current exoskeletons are not meeting the needs of their users. Solutions to the limitations offered may inform device development. However, the solutions are not infallible and thus further research and development is required