Optimal Traction Control In A Wheelchair With Legs And Wheels

We propose a proof-of-concept prototype wheelchair with legs for people with motor disabilities with the objective of demonstrating the feasibility of a completely new approach to mobility. Our prototype system is a vehicle equipped with powered wheels and legs and is capable of traversing uneven terrain and circumventing obstacles such as steps and ditches. The design combines the advantages of legged locomotion (versatility, adaptability) with wheeled locomotion (reliability, superior stability). When the wheels and legs are employed together, the system is redundantly actuated. In this paper, we describe a coordination scheme that allows us to optimize the tractive capabilities of the vehicle. The basic underlying idea is to minimize the tendency of the wheels and legs to slip. This is accomplished by minimizing the largest friction angle at all the locomotion elements. We briefly describe our experimental prototype. Simulation and experiments are used to demonstrate the performance of the active traction optimization scheme.