This paper presents the design and fabrication of an electric-powered wheelchair aimed at improving mobility and independence for individuals with physical disabilities. The system features a motorized lifting mechanism to assist in vertical transitions, such as from a bed to a restroom, minimizing the need for caregiver assistance. A dynamic model based on nonlinear differential equations was developed to simulate motion and analyze system behavior under varied surface conditions. A modified Proportional-Integral-Derivative (PID) controller is integrated to provide adaptive response based on user load and terrain. The system is implemented using a microcontroller-based platform, with real-time experimental results validating performance, stability, and user safety. The proposed design offers a practical and user-centric solution for addressing common limitations in existing wheelchair systems.
Introduction
A wheelchair is a mobility aid designed to assist individuals with impaired walking ability. Electric-powered wheelchairs, controlled via joystick, provide enhanced autonomy for users unable to manually propel themselves. However, conventional wheelchairs have limitations, especially regarding assistance during daily activities like transfers and toileting, which often require caregiver intervention and can be uncomfortable or unsafe.
This study proposes a power wheelchair equipped with an integrated hydraulic lifting mechanism to facilitate vertical seat movement, improving user independence and safety during transfers (e.g., from bed to restroom). The design also addresses dynamic stability and slip risks on uneven or low-friction surfaces.
The paper reviews previous research on electric wheelchairs with features like lifting functions, multifunctionality (bed conversion, bathing support), and caregiver assistance. Key components used in the design include hydraulic bottle jacks for lifting, DC motors for power, batteries for energy storage, mild steel square bars for the frame, and nylon wheels for mobility.
The wheelchair’s working principle relies on hydraulic jack operation powered by a DC motor, allowing smooth seat height adjustment based on Pascal’s Law, enabling safer and easier transfers.
Testing involved compressive strength evaluations and performance metrics of the hydraulic system and frame, demonstrating adequate lifting capacity (2 tons) and structural integrity suitable for users weighing up to 120–150 kg.
The design aligns with ergonomic and environmental considerations, aiming to improve comfort, safety, and autonomy for users with mobility impairments.
Conclusion
In this project, we proposed a novel electric wheelchair equipped with a lifting mechanism designed specifically for users with disabilities affecting both upper and lower limbs. The system facilitates smooth and secure transfers to and from beds or toilet seats, thanks to an innovative wheel arrangement that differs from that of conventional wheelchairs. Additionally, the foldable frame associated with the lifting mechanism enables this wheelchair to be safely operated on public roads. Experimental results demonstrated that the wheelchair provides excellent manoeuvrability—comparable to a forklift—and is capable of climbing a 100 mm step and functioning effectively on uneven surfaces, including restrooms. It is designed for users who can maintain a seated posture and can also assist in lifting users from a lying position. While the system offers several advantages, practical use may be influenced by individual physical conditions and restroom configurations. Nonetheless, the proposed design represents a significant step toward improving mobility and autonomy for physically challenged individuals.
References
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