Feasibility Study of a Fall Prevention Cold Gas Thruster

This paper presents the design and preliminary testing of an electronically-controlled cold-gas-thruster intended to potentially be used as a backpack-worn device for fall prevention for individuals at fall risk. The device is comprised of a high-pressure air tank, a pilot-operated valve, and a nozzle, which are employed together to create a thrust intended to correct a state of imbalance. The authors first employed modeling and simulation of the thruster-based system to assess feasibility of such a device, and based on these results designed and constructed a device prototype. The prototype was then tested on a rocking block that was used as an experimental model of a standing human subject. Experiments were conducted to assess the angular response of the rocking block starting from various initial tilt angles, both with and without the use of the cold gas thruster. For the experiments with the thruster, the valve was energized at the moment of release, thereby activating the cold-gas thruster, the thrust of which was directed to oppose the “fall.” A comparison between the two cases indicates that the fall prevention prototype increased the region of block stability by more than a factor of three (from a tilt angle of approximately 7 to 26 deg).