Adaptive body fitness equipment using magnetorheological fluids

Nowadays, keeping fit has been increasingly popular to people. Body trimmers are one of the fitness equipments that can help to improve the body shape by strengthening the back and side muscles of the user. However, body trimmers commercially available in the market are non-adjustable. That is, users can only exercise their muscles with a fixed load, which may not be suitable for all users. To provide various levels of training for different users, body trimmers with adjustable loads are preferred. Recently, magnetorheological (MR) fluids have been used for providing controllable change of states between semi-solids and liquids when a magnetic field is applied or removed. In this paper, the rotary brake with the use of MR fluids is applied to the body trimmer. By changing the electromagnetic field applied to the MR fluids inside the rotary brake, users are allowed to adjust the load set in the fitness equipment, to achieve preferable exercises. A multi-coils MR rotary brake is designed, fabricated and tested. Then the brake is assembled with a body trimmer to investigate the feasibility and effectiveness of the body fitness equipment with the developed MR rotary brake