Over 1.3 billion people, about 16 % of the global population, suffer significant mobility impairments as of 2024. People with mobility impairments usually struggle with performing activities of daily living (ADLs), reducing their living quality. Assistive robots are a solution to support ADLs. However, the rigid structure of current assistive robots may cause secondary injuries due to safety, comfort, and suitability challenges for delicate health conditions. To overcome these challenges, this research introduces a novel soft wheelchairmounted assistive robot named FlexPAL (Flexible Pneumatic Actuated Linkage) to provide safer, more comfortable and userfriendly daily assistance for people with mobility impairments. FlexPAL's lightweight ($\mathbf{3.88kg}$) modular design allows size adjustments for diverse user needs. Its soft design ensures users' safety through controlled and gentle assistance. Its adaptable structure integrates seamlessly into daily scenarios within its $400 \times 400 \times 400 \text{mm}$ workspace, delivering precise assistance (mean error $=15.95 \text{mm}$) for payloads up to 1 kg, suitable for most ADLs. The usability was evaluated based on the user case study with one healthy participant. The results of this research illustrate the high potential of soft wheelchair-mounted assistive robotics (FlexPAL) to address the limitations of rigid systems by offering higher adaptability, safety (i.e. assistance and humanrobot interaction) and user comfort, making it more effective for assistance.
Artificial hands are developed and employed widely for solving challenges in present-day robotics, with an increasing number of such systems being integrated into our daily lives. For humanoid or human-centric applications in medical or industrial sectors demanding increased naturality, biomimetics offers a promising approach. However, replicating biological structures and functions to the detail commonly results in excessive complexity in both design and production, preventing widespread adoption. This work presents a biomimetic hand developed with the use of modern procedural design methods and additive and textile production technologies, evaluated with a modular actuator frame through grasp and gesture demonstrations and finger trajectory analysis. The results aim to exemplify how leveraging these advancements may enable the creation of naturally compliant robotic devices with intricate functionality, while simultaneously satisfying the industrial requirements for robustness, cost-effectiveness and production scalability, therefore bringing the universal applicability of such systems within reach.
During daily life activities we not only gather information regarding the environment, but also regarding other humans which are performing similar actions. Even if not specifically required by the task, people affect other motion plans through different sensory modalities and may align their plans in a subtle way even if not required. This study explores the role of visual and auditory feedback in tasks with a sensory connection between partners. We used a dual robotic interface to test various visual and auditory coupling modalities, translating the spatial dynamics of the partners into distinctive feedback. Results from visual experiment showed that the explicit representation of the partner position along with own position greatly improves coordination between them. The auditory experiment emphasized the effectiveness of binaurally presented spatio-temporally discrete auditory cues. The current study provides insights relevant to the design of novel enriched rehabilitative protocols which rely on the mechanisms underlying interaction.
In the field of wearable robotics, assessing physical human-exoskeletons interaction (pHEI) is of critical importance in the development of wearable assistive devices. However, in the early stages of development of such devices, involving human testing could raise safety and ethical concerns. To address those limitations, we developed an active dummy leg named Leg Replica. Yet, the realism for pHEI was not adequate when mimicking soft-tissue behavior (compression and shear). The work presented here focused on identifying synthetic soft tissue simulants to enhance the fidelity of the Leg Replica, resulting in responses under compressive and shear stresses similar to those observed in human subjects. A novel approach is proposed in this work as a testing method for mechanical characterization of compressive and shear stresses of human soft tissues that is coherent with the specific application of wearable lower limb exoskeletons. The testing methodology was applied to 10 human subjects as well as the Leg Replica enhanced with three different platinum-catalyzed silicone material of varying hardness and thickness. One of the tested materials, with a thickness of 3 cm, demonstrated a mechanical behavior under compression and shear stresses comparable to that observed in human tissue. This study demonstrates the ability of the proposed methodology to objectively benchmark the adequacy of the Leg Replica combined with a new tissue simulant to mimic the biomechanical behavior of the human leg.
Stiff-Knee gait (SKG) is a common post-stroke impairment, marked by insufficient knee flexion during the swing phase, which reduces toe clearance, increases fall risk, and requires compensatory movements that can have adverse biomechanical effects. To address muscle weakness and paresis in SKG, assistive technologies, such as functional electrical stimulation (FES) and robotic exoskeletons, have been introduced. However, robotic assistance may inadvertently increase spinal reflex excitability by activating muscle stretch receptors, potentially worsening SKG. Previous studies suggest that SKG may stem from quadriceps hyperreflexia, particularly in the rectus femoris (RF) muscle. As such, assistive interventions could exacerbate, rather than alleviate, this condition via artificial activation of stretch receptors. In this study, we examined the impact of two FES modalities, plantarflexor and knee flexor assistance, on RF reflex excitability at rest and during gait in six post-stroke individuals with SKG. Results showed that, at rest, plantarflexor FES facilitated the RF reflex excitability, while knee flexor FES led to a slight inhibition. During gait, we observed that some individuals exhibited changes in reflex excitability during FES, but this effect was not as consistent as during rest. These preliminary results suggest that assistive technology such as FES modulates reflex excitability dependent on context.
