Design of a multifunctional integrated rehabilitation robot for elderly needs

Abstract

In domestic care settings, the lack of professional nursing labor severely restricts the ability of disabled elderly individuals to perform independent posture modulation and toileting. Existing assistive equipment has a strong functional fragmentation, usually requiring separate devices or manual handling for bed-to-chair transfers and postural adjustments. This study suggests a way to solve this structural imbalance by proposing an integrated, cost-effective, and highly adaptive intelligent wheelchair platform. The system includes an omnidirectional chassis with an asymmetric, diagonally opposite decoupled driving topology, a synchronous dual-actuator recling linkage, and an automated rack-and-pinion patient transfer mechanism using counter-rotating dual-layer conveyor belts. To assess the biomechanical interactions and confirm the effectiveness of the platform on fragile soft tissues, a rigid-flexible coupled dynamic simulation framework was designed. Specifically, a Key Decoupling Area with a locally refined mesh was modeled at the contact boundary via hyperelastic constitutive formulation, enabling the system to suppress micro-interface tangential friction while preserving macro-load bearing. Multi-body dynamic evaluations and structural finite element analyses show that the platform is safe under peak dynamic thrusts. More importantly, the transient stress characterizations show that the velocity-matched back-traction in the designated Key Decoupling Area successfully flattens the interface localized shear trajectories. This kinematic uncoupling effectively removes the tangential rigid scraping, and reduces the risks of localized skin-tear and tissue-tearing. Future work will prioritize the development and integration of an enhanced experimental protype. In the next development cycle, research efforts will mainly focus on developing a multimodal interaction framework and an adaptive decision-making system, which are supposed to significantly improve the operational autonomy of the intelligent caregiving wheelchair, enabling it to seamlessly perceive user intent and dynamically adjust to unstructured domestic environments