FPV Challenge 2021-22

The Fluid Power Vehicle Challenge is a yearly competition that the Murray State ISA club participates in.

The objective of the challenge is to use human power such as pedaling to charge an accumulator and then release that pressure to power the bike.

(The bike can continue to be pedaled while the pressure is being released).

The speed at which the pressure is released and the gearing/motors used when releasing that pressure is a crucial part of the design and it is the one that my team tackled.

There are three different races: the sprint race in which you try and go as fast as possible in the shortest amount of time.

The efficiency race where you attempt to go as far as possible.

And the endurance race where you go as long as possible.

The motors my team selected are shown above. The Marzocchi's are said to be highly efficient which is crucial to our design.

The Hydroleduc is both on hand, having been used in a previous years bike, and very efficient at higher rpms.

The precharge pressure was determined by running a series of simulations with to determine the optimum psi.

However that number may change as we gather additional data as it did not plan for the fact that we will have an adjustable gearbox.

The gear ratios were determined both by running simulations, and constraints with part availabilities.

Due to budget constraints we are unable to justify making custom gears and as such we are stuck with off the shelf options.

Another constraint was just the limits of the human body, which determined our braking ratio.

Above you can see the theoretical calculations for our performance in the sprint race.

We should be able to hit a max speed of 35 mph at around 5 seconds and then coast down from that speed for the remainder of the race.

With this speed we should finish the race in 20 seconds.

Due to the imperfect nature of simulation the real world number are likely to be different from the theoretical figures, however these do give us a useful picture of what we need to prepare for.

Further experimentation with both pressure precharge and variable gearing, should allow us to improve upon these figures somewhat.

This particular slide is referencing to a custom panel I am designing.

I believe that it could allow team members to see valuable information from outside of the vehicle, helping to better tune the device.

It would also add "style points" which is a consideration in this competition.

As the competition approached we were pressed for time, and had to lay off many ideas that we had hoped to bring to the bike.

However we were able to do some cool additions including adding a 5 speed Harley Davidson motorcycle to the bikes power train which was actuated pneumatically using buttons which fed into a PLC

Above is 2 videos of the bike launching on race day

We came in second place overall securing $3000 in prize money which was split among the team, and $1000 which was earmarked for the fluid power program at Murray State