BIMGEC - Zero Gravity exercise device

Weight in a weightless environment

The Bio-Inspired Micro Gravity Exercise Concept is a compact, lightweight workout machine designed to offset the osteoporosis, muscular atrophy and negative psychological issues associated with long-term space travel. BIMGEC emulates weight in zero gravity, both for weight training exercises and as a rowing machine for aerobic workouts. It incorporates a unique eccentric bias system to increase the effective load during the eccentric phase of a rep. BIMGEC was designed for an open call by NASA for a Bio-Inspired Advanced Exercise Concept for use in their Orion capsule for future manned interplanetary missions. BIMGEC won first place honours both for its innovation, a paradigm shift in zero gravity exercise design and due to its short-term feasbility, for the completeness of the design and for its use of practical materials and manufacturing processes.

Force Generation - Weight in a weightless environment

Nature provided inspiration for the method of resistance generation in the form of a Chameleon’s tongue which can store energy in a collagen spiral structure for release when required. The tongue is analogized here by spiral-form constant torque springs which are arranged in opposing pairs. The pairs are stacked to form a battery of 8 springs to deliver the required resistance. Linearity of resistance is ensured by tapering the springs along their length to counteract the effective torque gain as they spool onto the torque drum.The BIMGEC can be used as a weight emulating machine for resistive training, a rowing machine for aerobic workouts and also incorporates an eccentric bias function to increase the effective load for the eccentric phase of a rep.

Force Variation - Designing a gearbox with infinite gears

A toroidal, continuously variable transmission, typically used in small hybrid cars, was designed for the application as the resolution is effectively infinite. In order to meet the mass requirements, the entire gearbox had to be designed from scratch, it weighs less than 2kg without fluid. The spring battery delivers a constant resistive torque, so the effective "weight" that the user experiences is varied by changing the gear ratio between the input and output shafts. This is done by altering the pitch angle of a trio of drive wheels between a pair of toroidal plates by rotating the selector housing to the desired setting. The drive wheel and toroid faces are smooth, so traction is generated by means of a pressurised traction fluid which greatly increases in viscosity when put under shear loading by the moving faces. When in use, workout specific equipment is attached to the blue eyelet, a handle can be attached for rowing exercises, a harness for squats, etc.

Load Profile Variation - It weighs more as you lower it

The load profile can be varied between aerobic, resistive and eccentric bias settings. The mode is selected using the blue lever, which will engage different epicyclic gearsets to
the MGU (Motor-Generator Unit) depending on the setting. In aerobic mode, BIMGEC acts like a rowing machine, workouts requiring up to 750W of continuous power can be achieved. In resistive mode, BIMGEC becomes a typical weight training system, it can deliver from as little as 12kg to over 180kg of concentric resistive force with infinite resolution between these settings. Eccentric bias mode was the biggest technical challenge of the whole project. BIMGEC can increase effective weight during the eccentric phase of a rep (as the weight is lowered towards the ground) without relying on any external power requirements. This is achieved by storing the energy produced during the aerobic phase and releasing it during the eccentric phase to augment the force of the springs using the MGU. Eccentric gain can be trimmed anywhere between 0% and 100% of the concentric load, providing over 360kg at maximum setting.

Dimensions

The entire system weighs 9kg and is roughly the size of a shoe box.

Awards

BIMGEC was awarded a Red Dot Award for Life Sciences and a Platinum A' Design Award for Engineering and Technical Design.

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