Hopper 2 Exercise Device
A follow on to our original Grasshopper, the Hopper 2 is a wearable robotic device to address muscle and bone density loss for astronauts spending extended periods of time in zero-gravity. It was developed through a NASA funded project to investigate robotic exoskeleton devices. The Grasshopper connects to the user's torso like a hiking backpack, over the shoulders and around the waist. At the feet are footplates that the user is strapped to. There are two actuators, one at each "knee" joint, which are capable of high fidelity torque control. Because the Hopper uses motors instead of gravity to create the load on the user, the device is suited for use on space missions. Exercise in zero-gravity conditions is critical to maintain muscle strength and bone mass.
In operation, the actuators try to fold up, or collapse, putting a compressive load between the user's feet and torso. This force is similar to carrying a heavy backpack. The user then bends and extends his or her knees, replicating a weightlifting squat exercise. The applied load is precisely controller by a computer, and can be programmed to simulate gravitation loads or any desired load prescription, such as free-weight squat exercise. It is even possible to perform eccentric muscle exercises, or negatives, without the need for a spotter. Because the hip joints, as well as the spine and long leg bones, are in the applied load path, there is the potential to stimulate bone growth, countering the typical bone loss when astronauts return from extended duration space travel.
Peter Neuhaus, Lead
The Hopper has been shipped to NASA JSC for testing!