STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

There was no Federal funding used for this invention.

FIELD OF THE INVENTION

The present disclosure relates to augmented running devices, and more particularly, to augmented running devices that utilize one or more variable stiffness springs.

BACKGROUND

The top speed of human running is less than half the top speed of cycling, despite both motions being human-powered. Cycling is faster than running partly because (1) the rolling motion of the wheels prevents collision energy losses from stepping, (2) wheels can support the weight of the body in place of the legs, but also because (3) pedals enable the human to supply energy continuously in the air instead of intermittently when the leg is on the ground. These three features enable the bicycle to double the top speed of running, despite supplying no external energy and adding to the weight of the human.

Current running exoskeletons use fixed-stiffness springs in parallel with the legs to support the body and prevent collisional energy losses but require the human to supply energy while pushing against the ground, as in natural running. These exoskeletons have limitations in reducing the metabolic cost of running or increasing the top speed of running. The limitations have been attributed to both the energy required to swing the legs with the added mass of the exoskeleton and inefficient energy transfer between the human and the exoskeleton.

However, with a hypothesized ideal massless exoskeleton and perfect energy transfer between the human and the exoskeleton, the speed limit of the human augmented with a fixed stiffness spring would remain considerably below (65%) the air resistance speed limit in cycling (100%). This is because, despite using springs in parallel with the legs, the ground contact time reduces to 0.1 s at the top speed of natural running, which limits the amount of energy the legs can supply while pushing against the ground in high-speed running.

SUMMARY

Embodiments of the present disclosure provide apparatuses for augmenting human speed and the like. An embodiment of the present disclosure includes an augmented running device to increase a running speed of a user. The device can include a spring configured to be removably coupled to a user. The device can also include a variable stiffness mechanism that can selectively modify the stiffness of the spring, and a clutch for intermittently coupling and decoupling the spring from the user. The spring is compressed by the user during the swing phase of user's running cycle and is released when the user impacts a running surface to propel the user forward.

An embodiment of the present disclosure also includes a human-driven compliant mechanism. The mechanism includes an elastic energy storage element that is configured to capture energy supplied by the human and an adjustable lever that can vary the stiffness of the elastic energy storage element. The human-driven compliant mechanism is operable to selectively release the captured energy supplied by the human to provide force and power output beyond the physical capability of the human.

An embodiment of the present disclosure also includes an artificial limb operable to augment human movement. The artificial limb can include a pedal configured to be removably coupled to a limb of a user, a cam, a crank coupled to the pedal and operable to rotate the cam, and a variable stiffness spring in mechanical communication with the cam. The variable stiffness spring can be configured to selectively store and subsequently release energy generated by the human movement.

Other compositions, apparatus, methods, features, and advantages will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional compositions, apparatus, methods, features and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

