View Full Version : 3rd level climb even possible?
gobrewcrew95
14-01-2013, 21:43
My question is exactly as stated above.
Is a third level climb even possible?
Yes, it is achievable right away at the start of the match, but what about at the END of the match?
After your robot has driven around the field and taken shots at the goal, how much battery power would you even have left?
Then, is it enough to get your robot at least 60", most likely more, to get the third level climbing points?
If anyone could please answer the question(s), that'd be great. Feel free to leave a comment or concern related to this topic too.
nighterfighter
14-01-2013, 21:45
Yes it is possible.
You will see it happen in the next 6 to 8 weeks.
Rangel(kf7fdb)
14-01-2013, 21:50
My question is exactly as stated above.
Is a third level climb even possible?
Yes, it is achievable right away at the start of the match, but what about at the END of the match?
After your robot has driven around the field and taken shots at the goal, how much battery power would you even have left?
Then, is it enough to get your robot at least 90", most likely more, to get the third level climbing points?
If anyone could please answer the question(s), that'd be great. Feel free to leave a comment or concern related to this topic too.
We did some math and we calculated that we can climb at a rate of 2ft per second with 2 cims driving our climber. Of course we are probably going to gear it down because we don't want it to climb that fast. If ours works, we can probably climb in roughly 10-15 seconds. Especially if you have your climbing procedure automated.
Dr. Shocker
14-01-2013, 21:50
I would just like to point out that you do not need to get 90" off the ground, the lowest part of your robot just needs to be ABOVE 60.75" or so off the ground. (.75" for the radius of the pipe) Whether or not this makes it seem more or less possible is up to you.
gobrewcrew95
14-01-2013, 21:52
I would just like to point out that you do not need to get 90" off the ground, the lowest part of your robot just needs to be ABOVE 60.75" or so off the ground. (.75" for the radius of the pipe) Whether or not this makes it seem more or less possible is up to you.
You're correct, my bad. Change has been made.
We've run our battery off of a single charge for well over a half an hour driving around, shooting, ramming, and balancing while practicing last year, so I don't see power as being too much of an issue. That is, as long as you have enough batteries and enough chargers to have a full charge every match, you should be fine.
I might add that using pneumatics completely circumvents the problem of battery drop.
Pneumatics is also very powerful and will hold after power-down, unlike some motor mechanisms that have no mechanical stop.
Andrew Lawrence
14-01-2013, 22:29
Anything's possible.
Its quite possible. I dont think the GDC would issue an impossible challenge.
F22Rapture
14-01-2013, 23:31
I might add that using pneumatics completely circumvents the problem of battery drop.
Pneumatics is also very powerful and will hold after power-down, unlike some motor mechanisms that have no mechanical stop.
How would you implement a pneumatic climber? I could definitely see using pneumatics to actuate claws, but aren't they mostly useful for pushing and not pulling, as the majority of the movement in the climb would be?
kingbrandon14
14-01-2013, 23:37
We did some math and we calculated that we can climb at a rate of 2ft per second with 2 cims driving our climber. Of course we are probably going to gear it down because we don't want it to climb that fast. If ours works, we can probably climb in roughly 10-15 seconds. Especially if you have your climbing procedure automated.
When your team gets your climber working well, could you post a video of it climbing? I'm interested in seeing other teams' approaches to the pyramid :]
DampRobot
14-01-2013, 23:40
Implying that it is impossible is not a very productive use of time. Although some things are impossible, this is not one of them. It is simply really, really hard.
We will not see many 30pt climbs this season. A shooter is a lot easier to build. But that is not to say that you should not consider trying to build a climber.
Implying that it is impossible is not a very productive use of time. Although some things are impossible, this is not one of them. It is simply really, really hard.
We will not see many 30pt climbs this season. A shooter is a lot easier to build. But that is not to say that you should not consider trying to build a climber.
Honestly Im really curious as to how successful teams will be with the 30 pt climb this year. I simply dont know.
gobrewcrew95
15-01-2013, 09:28
Its quite possible. I dont think the GDC would issue an impossible challenge.
Of course I believe its possible, but few teams will be able to. I see part of the challenge this year is to either sacrifice a high climb and be a good shooter, or sacrifice shooting and be a dedicated 3rd level climber.
Implying that it is impossible is not a very productive use of time. Although some things are impossible, this is not one of them. It is simply really, really hard.
We will not see many 30pt climbs this season. A shooter is a lot easier to build. But that is not to say that you should not consider trying to build a climber.
My team has spent awhile designing and coming up with ways to climb and we even have a design that would work for level 3. But then one of our mentors pointed out how much battery power it would take to get to the 3rd level. So we actually designed two climbers. One for a quick level one climb and a 3rd level climb if we want to take the risk.
I'm really hoping that this year we'll see the first triple-hybrid mechanism -- one that uses motors, pneumatics AND constant-force springs to move up the pyramid. It's the perfect year for it, and totally removes the issues with battery drain. Essentially the motor must overcome the force of the spring to put a latch in place, then the motor reverses while the cylinder kicks in and all 3 force-providing mechanisms pull the robot up.
I think a 30-pt climb is possible, but the sacrifice for 99% of the teams needs to be evaluated on a team-by-team basis (I think only 1% of teams are even capable of doing a 30-pt climb while also being good at everything else). For us, it just isn't there (sad face).
Peter Matteson
15-01-2013, 09:59
How would you implement a pneumatic climber? I could definitely see using pneumatics to actuate claws, but aren't they mostly useful for pushing and not pulling, as the majority of the movement in the climb would be?
They can be used to drive linkages that lift the entire robot.
This really isn't that tough to design, the biggest issue is the weight of the cylinders and the volume of air needed to drive the system, However I haven't put too much thought into it yet but I'm sure it can be done.
pfreivald
15-01-2013, 11:44
They can be used to drive linkages that lift the entire robot.
This really isn't that tough to design, the biggest issue is the weight of the cylinders and the volume of air needed to drive the system, However I haven't put too much thought into it yet but I'm sure it can be done.
My math on the air charge needed makes a linear pneumatic system untenable. Combined with other mechanisms it becomes much more viable.
SciBorg Dave
15-01-2013, 14:30
Is the 30 point climb worth the effort. I think we will see teams do the 30 point climb on the first weekend of the regionals. I also think we will see teams fall from 3 to 5 feet and distroy their robot for the weekend. It is easy to do a 10 point climb with the only problem to worry about is a robot falling on you from above. I think the climb is not the game changer, the changer is getting the 6 disc in the top of the pyramid (30 points). I do not think that the 30 point climb is worth the effort if it DOES NOT takes away from your shooting abilities.
ablatner
15-01-2013, 22:51
Looking back at 2010, battery power really isn't a problem.
pfreivald
15-01-2013, 22:55
Looking back at 2010, battery power really isn't a problem.
Are you sure? Two feet isn't six.
Grim Tuesday
15-01-2013, 23:03
Are you sure? Two feet isn't six.
Not only battery power but I'm especially worried about teams who plan to use pneumatic power. There are only so many tanks you can strap onto your robot.
pfreivald
15-01-2013, 23:23
Not only battery power but I'm especially worried about teams who plan to use pneumatic power. There are only so many tanks you can strap onto your robot.
Unassisted pneumatics are not a viable solution, to be sure.
Run out of battery power? No way.
Let's do some math:
150 lbs ~= 70 kg
Assume you want to raise your robot 2 meters (78 inches)
PE = m*g*h = 70 kg * 9.8 m/s^2 * 2 = 1400 Joules
The battery has an 18 Amp-hour capacity (although you don't this much out of it in practice).
18 Ah * 12 V = 18 * 12 * 3600 Volts*Amps*seconds = 78 kJ
So climbing would use just under 2% of your battery power.
Or, looked at another way, let's assume your robot has a maximum speed of 4 meters per second (13 feet/second). To accelerate to top speed requires
KE = 1/2 * m * v^2 = 1/2 * 70 kg * (4 m/s) ^ 2 = 560 Joules
So, if we pretend that all our mechanisms are frictionless and 100% efficient, sprinting from one side of the field to the other three times is very roughly equivalent to climbing the tower.
I could definitely see using pneumatics to actuate claws, but aren't they mostly useful for pushing and not pulling, as the majority of the movement in the climb would be?
No. In fact, I've heard it argued that you should always use pneumatics to pull, rather than push, because that way you don't put the rod into compression and risk bending it.
pfreivald
15-01-2013, 23:37
Run out of battery power? No way.
After an entire match of compressor running, pushing/shoving, shooting, etc, etc?
Entirely possible to not have the oomph necessary to do what was designed to be done at "12V"*, especially if the design doesn't compensate for the drop in available voltage after ~90 seconds or so of a match.
*Likely more, as 12V batteries aren't, well, 12V.
Yes, it's possible to kill your battery, and designing your climbing system for a fresh battery is unwise. But it's pretty rare that robots can't still drive across the field by the end of the match. Power-wise, climbing isn't actually any worse than driving around.
Yes, it's possible to kill your battery, and designing your climbing system for a fresh battery is unwise. But it's pretty rare that robots can't still drive across the field by the end of the match. Power-wise, climbing isn't actually any worse than driving around.
Yep. We're climbing to the third with only two FP motors right now (I think they're illegal, but its just for the prototype as of now)
karomata
16-01-2013, 11:40
It is very possible, but also very hard. That's why its worth 30 points, so that teams will actually attempt it.
Daniel_LaFleur
16-01-2013, 14:44
No. In fact, I've heard it argued that you should always use pneumatics to pull, rather than push, because that way you don't put the rod into compression and risk bending it.
Steven,
Keeping the rod in tension rather than compression is a good idea, but you should actually do the bending calculations before ruling out pushing with a cylinder. Most cylindars are designed so that their rods can handle max force the cylindar can produce in compression. Rods are typically destroyed by side loads.
Also cylinders usually have more push force than pull force due to the area taken up by the rod.
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