Design Optimization of a Single-DoF Gait Rehabilitation Robot for a Domestic Environment

Abstract

In an aging society, the need for rehabilitation treatment is expected to rise. As current healthcare systems have limited capacity and personnel, access to rehabilitation devices usable in households can help address the demand. A lower-limb rehabilitation robot designed for home use must be adaptable to accommodate acute and chronic rehabilitation phases. Existing devices are mechanically complex and require intricate, patient-specific adjustments. To address this, we propose a single degree of freedom (DoF) mechanism based on a chain drive that can be used in multiple configurations, inside and outside a patient bed. We model the gait pattern and construct a custom cost function that captures key features of natural human walking. This cost function is then used to optimize the design parameters of the robot via a direct-search solver to accommodate patients of varying sizes and achieve effective rehabilitation with a fixed trajectory. The outcome is validated experimentally by comparing two robot configurations with five healthy subjects.