Students discover real-life challenges in using fluid power for human-and hydraulic-powered bike
An oil actuated cylinder, driven by a cam that replaced the usual chain ring, powered California Polytechnic's entry on the difficult hilly terrain.
The University of California at Irvine fielded the only pneumatically-powered prototype. The bike used cylinders to charge 14 student-designed reservoirs, which then discharged to a pneumatic drive cylinder by way of four digitally controlled servovalves.
Murray State's recumbent entry was able to charge two hydraulic accumulators to 2500 psi, and provide a gauge reading to the operator. The accumulated pressure could be directed to the rear wheel by way of an on/off control valve.
It was an uphill battle for many teams in the first annual Chainless Challenge, sponsored by Parker Hannifin Corp. Literally. The use of hydraulic cylinders, accumulators, and fluid, as well as pneumatic power, was tough on the student teams that competed to build a human-and hydraulic-powered bicycle.
Most of the teams' designs were functional at least in part, but the real test of their knowledge of fluid power came on the steep hills they had to climb with their altered bikes. It was difficult for all; and only a few managed to make it up all the hills on the 12-mile circuit in Cleveland's Brecksville Metroparks Reservation.
Of the 10 teams from nine universities that were meant to run the race, only seven started the race.
The students said the biggest challenge in their designs was finding a pump with speed to match a human's ability. Most hydraulic pumps are designed for much higher speeds than any speed a human can pedal a bike.
For all students, the Parker competition-was the first time they worked with fluid power, so they had to learn the technology as they began to design their bikes. Larry Schrader Jr., Global Motion and Control Training Manager for Parker, said in the competition to be held next year, Parker will work with the students to find components, such as accumulators, that will be lighter in weight and smaller to better fit a bicycle design.
"Now that they're back, the students want to design their own pumps, so this competition has achieved one of its major goals — bringing some interest to the fluid power industry," Schrader offered.
The University of Illinois took several honors in the race, including winner of the speed circuit, manufacturability, marketability, and cost. This allowed the team to take highest overall score, notching the top spot as Best of Challenge.
Murray State University took home awards for the sprint race, reliability and safety, and workmanship. Cal-Poly — San Luis Obispo gave the best report, and University of California at Irvine won for ingenunity and novelty.