Wheelchair Design with Variable Posture Adjustment and Obstacle-Overcoming Ability

To meet the needs of wheelchair users who wish to change their body posture to facilitate their life and move freely in complex environments, this study designs a wheelchair with functions of posture adjustment and overcoming obstacles. After analysis of these specific needs, the wheelchair structure is designed based on modular design principle to include a chair and mobile module. The chair module comprises back-posture adjustment and sliding mechanisms, and the mobile module comprises front, main, and auxiliary wheel-leg mechanism. In particular, the main and auxiliary wheel-leg mechanisms are the main structures for wheelchair movement. The different schemes are then compared and analyzed. On this basis, the kinematic models of each mechanism are established and the motion performance, including posture adjustment and ability to overcome obstacles, is analyzed in detail. Analysis of the mechanical properties provides a basis for the selection of driving components. The control system is designed, and the prototype of multifunctional wheelchair is developed. Experimental results show that the wheelchair can realize the adjustment of body posture and complete the process of moving up and down steps with good user stability. The wheelchair can considerably facilitate the movement of the disabled or the elderly.