This post is the ninth installment of our #SportsInSTEM Series, which explores, demonstrates, and illuminates how sport serves as a vehicle to train and enlighten students of all ages in pursuing interests and careers in science, technology, engineering, and mathematics (STEM) fields. If you or someone you know is using sports to help with STEM education, then please let us know so we can include their work in our series.
The weight room stands as a ubiquitous place for athletes of any level during the season or offseason. The time spent here to build their respective bodies to be ready for the pro ranks can be countless. There really isn’t any reasonable way to avoid this necessary work.
This environment, however, has remained rather unequipped with technological upgrades that serve safety purposes.
Of note, former USC Trojan running back Stafon Johnson’s incident highlights the perils that can happen inside a weight room. His spotter wasn’t paying attention when Johnson lifted a bar that carried 275 pounds. It abruptly fell on his neck, which caused him to undergo numerous surgeries to repair the almost-fatal neck and throat injuries incurred. The rest of the 2009 season immediately came to end for him; had few options but to sign as a free agent to the Tennessee Titans instead of being selected in the subsequent NFL Draft. A lawsuit that Johnson filed was finally settled two years ago.
Conversely, adequate solutions don’t tend to present themselves until after an unfortunate accident transpires such as Johnson’s experience. That’s the reality in today’s society. Technological innovation should be at the forefront of preventing various, potentially dangerous scenarios across sports. The development and implementation of this technology could be executed well ahead of time, too. The weight room, for one, does have plenty of areas that need to be addressed, specifically the aforementioned bench press issue.
College campuses–not that ironically–present an avenue for plausible answers to combat this problem. In North Carolina State University, four seniors did just that, when they worked with National Instruments to combine their engineering acumen and the latter’s LabView program resources. The project’s objective was to install a safer alternative to a human partner during weightlifting workouts. This new lifting partner intended to pose close to no distraction as possible in order to help the athlete in their exercise. Safety, above all else, accordingly, stood as the underlying consideration for the students’ design and construction of the device created.
Microcontroller programming, sensor integration, and mechanical design corresponded the primary functional aspects for this project, with National Instruments’ instrumentation to round out all of the system requirements. This model served to recognize struggle, ability to rack and unrack the bar, and offer a brief recapitulation of the performed workout. Barbell squats, skull crushers, and bench presses are among the types of lifts this system can sustain. Whenever the weightlifter gets to a climatic point where they aren’t physically able to complete another repetition, the adjacent partner would diffuse the weighted amount through placing an upward force.
The essential components that made this endeavor possible consisted of mechanical and electrical subsystems: two ultrasonics sensors, video camera, NI’s sbRIO, PC processor, two linear actuators, fail safes, two DC motors with gearboxes, two motor controllers, two DC power supplies, and a metal weight rack frame.
The ultrasonic sensors help collect distance data in order for the actuators to maintain a defined space from the weight bar. The video camera allows to track a color code on the weight bar to understand its absolute placement. The recognition facet of the video assists in determining if an athlete is, indeed, having difficulty. The right amount of power would then be applied to the motor to enable the user to be aided from harm’s way. The mechanical fail safes attached to this robot ensures the athlete’s safety in the event that there’s a system malfunction, which are adjustable based on the user’s height.
On the software side, NI’s LabView programming graphical language enters the project, including video modules and several sensing capabilities. The designed programs for barbell squat and bench press get activated when the athlete nears the robot. The same algorithms for identifying bar distance are in play; keeping a constant distance derives from the PID controllers coupled with the ultrasonic sensors’ inputs. A loop code occurs every time a user slows down from his or her pace that would complete a full extension, which analyzes struggle detection.
In terms of the construction details pertinent to the mechanical design, the robot had to configure with the powerline weight lifting rack. The structure integrity held 600 pounds, while the linear actuators were bolted on each backside of the square tube with ten bolts for each of them. Despite these actuators being 1,710 millimeters, the students were able to place its input appendage on top of the rack to ensure the user virtually full range of motion. A quarter inch thick sheet of metal was installed on top of the machine, which provided a sturdy place for equipment. They added a crucial 13 inch piece of 2×4 wood in order to perfectly align the gearbox and actuator’s shafts juxtaposition. Since none of the other positions purport for arm functionality, all that was needed were for the surge protector and single board RIO to be in a centralized position for easy access; the power supplies, conveniently, were placed a bit further away insofar as to not heat up the other parts.
As for the software design elements, everything coded utilized NI’s LabView that consists of functional blocks connected by wires to create programs. Its interface lets the students to input exercise type, number of repetitions, the weight being lifted, and desired height for resting portion. The option to start and stop the exercise along with displaying reports of assistance needed after each repetition are instantly available. Its key feature enabled for bar tracking to happen due to the computer vision coupled with the ultrasonic sensing at the same time. The former garners the absolute vertical position of the bar via a pattern four different places from it and it outputs this value to a global variable; the latter registers the vertical position relative to the lifting arms, deduced from two ultrasonic sensors in conjunction with the RIO board. These characteristics comprised the primary ways to deploy this project.
Again, this robotic apparatus was assembled around a prototypical cage frame. The system would act like any normal rack when it isn’t used. The maximum weight it can safely support is 400 pounds. The single board RIO provides the right PWM signal to the motors that forces the arms to react, which constitutes the very essence to save athletes’ from severe injuries in the first place.
With under $1,600 budget, these NC State students were able to build a machine that would change current conditions in the weight room. Only a few aspects pertaining to functionality and design weren’t completed due time constraints. This model, though, clearly suffices to finish a more polished product that needs to be taken to market.
Big data continues to filter down throughout the college football landscape. True smart stadiums may take even longer to deploy, but at least STEM education demonstrates simpler solutions to some age-old problems that could be solved quicker than the former. A robotic lifting partner would represent a nice start.