A Novel Robotic Seat for Stabilizing Upper Body Posture

Nowadays, the elderly and the disabled are rapidly aging worldwide; therefore, the use of wheelchairs by the elderly and disabled continues to rise. However, many wheelchair users have difficulties adequately adjusting their sitting posture and often suffer from injurious falls, particularly, while traversing hilly roads or slowing down. In this study, a novel robotic seat is proposed to overcome these challenges, and numerical simulations are performed to verify its feasibility. The bottom of the seat is a spherical section, supported and driven by three omnidirectional wheels. An aluminum bar flanked with dumbbells is connected to the wheelchair through a universal joint as the test subject. The motion model is decoupled into two 2-D inverted pendulum models in the vertical plane and one rotation model in the horizontal plane. Two linear state feedback controllers based on the linear quadratic regulator method are used to stabilize the test subject in the vertical plane. The simulation results demonstrate the feasibility of the proposed robotic seat.