Development of virtual reality bike with cylindrical MR fluid brake

Cycling is a healthy and moderate aerobic exercise for the elderly and it works well not only to their physical functions but also to their mentalities. In order for the exercise machine that can facilitate the moderate aerobic exercise for users who cannot do real cycling, we have developed the virtual reality bike (VR Bike) with a cylindrical MR fluid brake. The aim of this paper is to describe (1) the development and integration of the total system of the VR Bike, and (2) the implementation of the controller for the pedaling torque in the straightway driving with slopes. The cylindrical MR fluid brake was connected to the pedal of a belt-driven bicycle and used to control pedal resistances depending on the environment of the virtual world. We formulated the torque characteristics of the brake and controlled the pedaling torque with the input current. Data of a 3D map were loaded in the VR Bike system and a subject ride a bike in the virtual world. The main controller calculated the dynamics of the bike and determined the pedaling resistance. Time profiles of the traveling speed and pedal torque during climbing up and down the slope were evaluated. Though quantitative evaluation has not conducted, the proposed system changes the pedal resistance depending on the conditions of the bike.