Optimal design of a wheelchair-mounted robotic arm for activities of daily living.

Abstract

Purpose: The increasing prevalence of upper limb dysfunctions due to stroke, spinal cord injuries, and multiple sclerosis presents a critical challenge in assistive technology: designing robotic arms that are both energy‑efficient and capable of effectively performing activities of daily living (ADLs). This challenge is exacerbated by the need to ensure these devices are accessible for non‑expert users and can operate within the spatial constraints typical of everyday environments. Despite advancements in wheelchair‑mounted robotic arms (WMRAs), existing designs do not achieve an optimal balance-minimizing energy consumption and space while maximizing kinematic performance and workspace. Most robotic arms can perform a range of ADLs, but they do not account for outdoor environments where energy conservation is crucial. Furthermore, the need for WMRAs to be compact in idle configurations-essential for navigating through doors or between aisles-adds another layer of complexity to their design. This paper addresses these multifaceted design challenges by proposing a novel objective function to optimize the link lengths of WMRAs, aiming to reduce energy consumption without compromising the robots' operational capabilities.

Materials and methods: To achieve this optimization, the scatter search method was employed, incorporating considerations of collision and singularity avoidance while ensuring the arm remains compact when not in use. The proposed design was evaluated through simulations and experimental validation with both healthy subjects and individuals with lower limb dysfunctions.

Results and conclusions: The optimized WMRA demonstrated significant improvements in energy efficiency and spatial adaptability while maintaining the required kinematic performance for ADLs. The validation process confirmed the practical applicability of the proposed design, highlighting its potential to enhance mobility and independence for individuals with upper limb impairments. This study contributes to the field of disability and rehabilitation by providing a structured approach to designing assistive robotic arms that better align with real‑world constraints and user needs.