Kinematic Model of a New Staircase Climbing Wheelchair and its Experimental Validation

Abstract

This paper describes the mechanical devices, the movements and the associated kinematic models of a novel wheelchair prototype capable of climbing staircases. The key feature of the mechanical design is the use of two decoupled mechanisms in each axle, one used to negotiate steps, and the other to position the axle with respect to the chair to accommodate the overall slope. This decoupling makes possible many different climbing strategies, the overall mechanism being extraordinarily versatile from a control point of view. Kinematic models have been developed for the different mechanical configurations that appear during all the ascend/descend processes. These models are required to control the actuators of the wheelchair in such a way that its centre of mass is able to follow arbitrary spatial trajectories. This is very important as one has to design very smooth spatial trajectories, keeping a near null inclination of the seat all the time in order to guarantee the comfort of the passenger, usually a handicapped or injured person. A real prototype is presented, and experimental results are reported that show the efficiency of the mechanism and the accuracy of the kinematic models developed.

Robust control of underactuated wheeled mobile manipulators using GPI disturbance observers

“…Digital computer simulations were provided, in which where the efficiency of the proposed control method was assessed with regard to large initial errors and substantial parametric uncertainties in the model. Future work will be devoted to verifying the application of the proposed control algorithms to reconfigurable stair-climbing mobility systems [34]- [36].…”

Dynamic control of a reconfigurable stair-climbing mobility system

“…The kinematic model 15 and the trajectory generation 18 allow full motion of the degrees of freedom of the whole system, and can be adapted to a continuous smooth profile or a discontinuous profile consisting of a flat floor and a staircase. Furthermore, the choice of an appropriate movement strategy influences the verticality of the chair frame, the passenger comfort (the SCMS will usually carry a passenger with physical disabilities), and the power consumption.…”

“…(15) where the values of the matrices B(r), C(r, r), and G(r) are given by the following expressions:…”

Software and Hardware control of a hybrid robot for switching between leg-type and wheel-type modes

“…A wheelchair becomes useless when faced with these barriers, and as a result, there has been a number of wheelchair designs that claim to be able to climb stairs (Morales et al, 2006). The wheelchair proposed in Morales et al (2004) was designed to enforce mechanical stability while the wheelchair is on the staircase.…”