Planetary operations motivate the testing of surface system elements such as rovers, excavators, habitats, deployables and space suits in planet-relevant gravity. There is demand for technologies that pave the way for large-scale planetary environment simulation, including gravity offloading systems. Gravity offloading is accomplished by applying a force to counteract some portion of Earth’s gravity to achieve an effective reduced gravity environment. The mission of this project is to produce a gravity offload system, which can be used in a variety of applications, such as analyzing lunar-readiness of the Polaris rover. This translates to testing various points of functionality (for example, mobility, terramechanics, sampling, drilling, etc.) in a low-gravity environment.
Our final deliverable will be construction of an ultra-light gantry crane bridge with a vertical degree of freedom to accommodate change in vertical location of the center of gravity of the test article. The gantry will be able to offset up to 300 lbs. of payload and move up to 1.5 m/s in velocity, 3 m/s2 in acceleration, in two axes with input from a position sensing system. Our lifting device, the Gorbel G-force IQ 330, will follow the position of the robot, constantly applying an upward tensioning force to simulate reduced gravity.
The 10-foot high gantry system is composed of a 24-foot long runway and a 10-foot wide bridge, bearing a carriage to house the lifting device used to offset the robot’s weight about its center of gravity. The actuation system for this gantry consists of two high power motors coupled with which drive a belt/pulley system in both the X- and Y-directions.
Over the course of the past 6 weeks, the team has selected the optimal method of actuation based on analysis and specifications, designed suitable parts considering performance and cost efficiency, finalized SolidWorks models of the actuation system, compiled a bill of materials, and ordered parts for assembly and bench testing in December and early next semester.
One of the foremost considerations of this project has been to provide a solution that minimizes cost without compromising performance, in order to bring the benefits of gravity offloading to a number of organizations and educational institutes. Our system can even function as a novelty attraction for people who want to experience low gravity environments here on Earth. “Imagine a world with reduced gravity!”