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Gravity Vehicle C
Posted: August 15th, 2019, 6:50 pm
by windu34
Gravity Vehicle C: Teams design, build and test one Vehicle and Ramp that uses the Vehicle's gravitational potential energy as its sole means of propulsion to reach a target as quickly and accurately as possible.
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Scoring
Posted: September 3rd, 2019, 2:00 pm
by AngelMB
Taking into account the new scoring methodology, I expect top scores to be significantly lower from the last time Gravity Vehicle was an event (high 200's I believe). If anything, they should be closer to the top scores that Mousetrap Vehicle had last year (Sub 20). Obviously we can't tell what times and accuracy vehicles will have right now, but I expect similar times to MV and an improvement to the accuracies we saw with MV as teams can slow down past the 8.5 meter mark to ensure less jumpiness and 'fish-tailing' that would occur from braking at high speeds.
Re: Scoring
Posted: September 3rd, 2019, 3:33 pm
by sciolyperson1
AngelMB wrote: ↑September 3rd, 2019, 2:00 pm
Taking into account the new scoring methodology, I expect top scores to be significantly lower from the last time Gravity Vehicle was an event (high 200's I believe). If anything, they should be closer to the top scores that Mousetrap Vehicle had last year (Sub 20). Obviously we can't tell what times and accuracy vehicles will have right now, but I expect similar times to MV and an improvement to the accuracies we saw with MV as teams can slow down past the 8.5 meter mark to ensure less jumpiness and 'fish-tailing' that would occur from braking at high speeds.
Can you clarify what you mean by the slow down past the 8.5m mark?
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 3:46 pm
by MTV<=>Operator
Can you clarify what you mean by the slow down past the 8.5m mark?
Given that the time is now taken by two photogates (one at the .5 meter mark and one at the 8.5 meter mark), teams can now adapt their vehicles to brake over a distance of half a meter because the shortest distance it will have to stop at is 9 meters. This 0.5 meter buffer distance would allow for a system (such as a wingnut with a spring) that would cause the vehicle to slow down before coming to a stop and would effectively reduce or eliminate skidding.
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 4:20 pm
by AngelMB
MTV<=>Operator wrote: ↑September 3rd, 2019, 3:46 pm
Can you clarify what you mean by the slow down past the 8.5m mark?
Given that the time is now taken by two photogates (one at the .5 meter mark and one at the 8.5 meter mark), teams can now adapt their vehicles to brake over a distance of half a meter because the shortest distance it will have to stop at is 9 meters. This 0.5 meter buffer distance would allow for a system (such as a wingnut with a spring) that would cause the vehicle to slow down before coming to a stop and would effectively reduce or eliminate skidding.
Precisely, I also believe the accuracy scores should be at least slightly better since the track once again follows a straight line rather than a curve like last year.
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 4:52 pm
by windu34
MTV<=>Operator wrote: ↑September 3rd, 2019, 3:46 pm
Given that the time is now taken by two photogates (one at the .5 meter mark and one at the 8.5 meter mark), teams can now adapt their vehicles to brake over a distance of half a meter because the shortest distance it will have to stop at is 9 meters. This 0.5 meter buffer distance would allow for a system (such as a wingnut with a spring) that would cause the vehicle to slow down before coming to a stop and would effectively reduce or eliminate skidding.
One thing to watch out for is making sure your vehicle still has enough momentum to reach the target point, a mistake I made doing EV back in the day.
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 7:43 pm
by chessbucket
Is it just me or is striving to make a brachistochrone curve or optimize time to reach the bottom of the ramp a useless consideration now that the timings start after the vehicle has left the ramp? Even if timing started when the vehicle was released, I doubt having a brachistochrone ramp curve would make a difference. IIRC, you would have to have the center of mass of the vehicle travel in the brachistochrone trajectory which is a pain. I predict 1-6 at nationals to be sub 10
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 8:16 pm
by Unome
chessbucket wrote: ↑September 3rd, 2019, 7:43 pm
Is it just me or is striving to make a brachistochrone curve or optimize time to reach the bottom of the ramp a useless consideration now that the timings start after the vehicle has left the ramp? Even if timing started when the vehicle was released, I doubt having a brachistochrone ramp curve would make a difference. IIRC, you would have to have the center of mass of the vehicle travel in the brachistochrone trajectory which is a pain. I predict 1-6 at nationals to be sub 10
You're right, from what I've heard. This was mentioned at SOSI.
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 8:29 pm
by someone1580
Where do you guys buy these specialized ramps? Also, what design do you recommend besides the Brachistichrone Curve?
Re: Gravity Vehicle C
Posted: September 3rd, 2019, 8:41 pm
by Unome
someone1580 wrote: ↑September 3rd, 2019, 8:29 pm
Where do you guys buy these specialized ramps?
Generally you build them.