15-12-2009 01:33

Qbranch

Re: pic: Air Suspension

Clever... since the pistons are all connected and of the same bore, the pressure and therefore the force on each wheel must be the same.

But since the weight distribution in your robot is not 100% even, do you8 have a problem with it sitting at a funny angle? Also is there a benefit to using double-acting pistons or could you save hose, fittings, and weight and go with single acting pistons?

Neat idea!

-q

15-12-2009 07:55

IKE

Re: pic: Air Suspension

Alec Issigonis, the designer of the original Mini, had similar designs for a hyrdraulic suspension back in the day.

Neat Idea although there are often added complexities to adding suspension. Chain tension can be problematic.

15-12-2009 07:57

joeweber

Re: pic: Air Suspension

We are using this design to replace our curent design. The old design cuts off the front of the robot and would create design problems with game collection peices. The new design clears the front and also makes it stronger.

Below is the old design

15-12-2009 08:40

Al Skierkiewicz

Re: pic: Air Suspension

Joe,
I would just like to make you aware that in the past, using mechanical force to move a piston and create pressure was deemed illegal under the robot rules. Each year pneumatic rules change but before you dedicate your design, please wait for kickoff and then ask the question through the Q&A.

15-12-2009 09:56

EricVanWyk

Re: pic: Air Suspension

Regardless of legality, have a few students write white papers on these different approaches. Make them thoroughly research and explain them, and include pictures of the beasts. It will make applying to college and getting scholarships into a cakewalk.

Very cool designs!

15-12-2009 10:18

Alan Anderson

Re: pic: Air Suspension

Quote:

Originally Posted by Al Skierkiewicz Joe, I would just like to make you aware that in the past, using mechanical force to move a piston and create pressure was deemed illegal under the robot rules...

15-12-2009 10:26

GaryVoshol

Re: pic: Air Suspension

You have to watch what this does to your bumper zone, should bumpers be required again this year.

15-12-2009 15:52

dtengineering

Re: pic: Air Suspension

Quote:

Originally Posted by Al Skierkiewicz Joe, ...using mechanical force to move a piston and create pressure was deemed illegal under the robot rules.

15-12-2009 16:18

NickE

Re: pic: Air Suspension

Quote:

Originally Posted by dtengineering Al makes a good point... but it got me thinking that a system like this could be tied in to the robot's pneumatic system and you could actively raise or lower the pressure in the system to achieve different ground clearances... when you want to hold position and not be pushed around, just lower the robot frame right down on to the ground!

15-12-2009 17:23

Al Skierkiewicz

Re: pic: Air Suspension

Creating pressure using mechanical force on legal pneumatic component has been deemed illegal in the past. Reasoning behind such a rule is the possibility of a pneumatic system already at full pressure, with flow restrictors, could conceivably exceed system pressure of 125 PSI if pushed on with enough force.

Also, until last year, pressure modulators were not allowed. Last year, a few changes in the rules did allow them and I remember seeing one robot that had somehow controlled a pressure regulator to achieve a desired effect. I don't remember if it proved advantageous or not.

15-12-2009 17:57

Rion Atkinson

Re: pic: Air Suspension

I am loving the idea. It would prove very advantageous for anything. It has true real world potential. If legal it FIRST I would love to see it on a bot.


I agree with Gary, bumpers could cause a problem..

15-12-2009 18:19

joeweber

Re: pic: Air Suspension

15-12-2009 18:24

EricH

Re: pic: Air Suspension

IIRC, Al, it did not extend to the generation of vacuums. I know of three separate instances where a team used 100% FRC-legal pneumatics to generate a vacuum via mechanical means. (2 in 2004 and 1 in 2007). All three were judged legal. It is possible to argue that this system creates 2 vacuum systems.

You could also make the argument that this effectively creates 2 closed-loop gas shocks, which have a rather off-and-on legality if I remember the past rules correctly. (Of course, then that begs the question of "Why not just do that on one cylinder instead of two?", but that's beside the point.)

And remember, now that we are in a bit of a rules discussion: 2010 rules may forbid pneumatics altogether or otherwise make this design either legal or illegal, so anything said here may or may not apply after 1/9/2010.

15-12-2009 18:28

Rion Atkinson

Re: pic: Air Suspension

Quote:

Originally Posted by joeweber As shown on our other post http://www.chiefdelphi.com/media/photos/34389? we would attach the bumpers to each section of the drives which would allow them to move up and down with the wheels keeping them at the correct height. The only problem I see is the bumpers could be called articulating which would be illegal. Far as the pneumatics I Like the idea of having a pressure relief valve and a pressure regulator to make it legal.

15-12-2009 18:32

Rion Atkinson

Re: pic: Air Suspension

Quote:

Originally Posted by EricH And remember, now that we are in a bit of a rules discussion: 2010 rules may forbid pneumatics altogether or otherwise make this design either legal or illegal, so anything said here may or may not apply after 1/9/2010.

15-12-2009 18:34

EricH

Re: pic: Air Suspension

Quote:

Originally Posted by Formerly Famous Seeing as the rookie teams KOP will come with a Air Compressor I have reason to believe that pneumatics will be legal.

15-12-2009 19:17

Jeffy

Re: pic: Air Suspension

Quote:

Originally Posted by dtengineering Al makes a good point... but it got me thinking that a system like this could be tied in to the robot's pneumatic system and you could actively raise or lower the pressure in the system to achieve different ground clearances... when you want to hold position and not be pushed around, just lower the robot frame right down on to the ground! But regardless of FRC legality, this is a cool project on its own right. Jason

16-12-2009 08:05

Al Skierkiewicz

Re: pic: Air Suspension

Eric,
Pneumatic vacuum using cylinders was allowed in 2007 after some discussion, in 2004 it was not. The only legal vacuum devices prior to 2007 were venturis which create vacuum but not by mechanical force. However, even these were not legal in most years.

From 2004 Robot Pneumatic section rules <R54> revised...

• A device that creates a vacuum is not considered to be a pneumatic device, and is allowed. This includes, but is not limited to, venturi-type vacuum generators and off-the-shelf vacuum devices (as long a they are powered by one of the Kit motors).

Some teams used vacuum pumps that were COTS items, removed the motors and replaced them with KOP motors. The FP was the motor of choice that year.

16-12-2009 12:40

EricH

Re: pic: Air Suspension

Quote:

Originally Posted by Al Skierkiewicz Eric, Pneumatic vacuum using cylinders was allowed in 2007 after some discussion, in 2004 it was not. The only legal vacuum devices prior to 2007 were venturis which create vacuum but not by mechanical force. However, even these were not legal in most years. From 2004 Robot Pneumatic section rules <R54> revised... • A device that creates a vacuum is not considered to be a pneumatic device, and is allowed. This includes, but is not limited to, venturi-type vacuum generators and off-the-shelf vacuum devices (as long a they are powered by one of the Kit motors). Some teams used vacuum pumps that were COTS items, removed the motors and replaced them with KOP motors. The FP was the motor of choice that year.

16-12-2009 15:42

Al Skierkiewicz

Re: pic: Air Suspension

Eric,
That is a possibility particularly if this was a week one or two event. I did not look into which Q&A prompted which Team Update, I merely quoted the final robot rules revision.
I do remember at least one team, buying a cheap vacuum cleaner and replacing the motor with an FP. It worked fairly well as I remember.

16-12-2009 18:12

Brandon Holley

Re: pic: Air Suspension

Quote:

Originally Posted by EricH Then two teams were using illegal mechanisms in 2004; a pair of West Coast teams used a setup similar to 386's 2007 one to try to create suction on the 2X ball.

20-12-2009 13:31

joeweber

Re: pic: Air Suspension

Installed the air suspension. It does work but requires too much work to make it usefull. Keeping the correct pressure and all the systems needed is no justifiable.

30-12-2009 13:04

Elgin Clock

Re: pic: Air Suspension

It's not just your bumper zone you can throw out of whack with a design like that, it's your whole profile!
We had a drop down wheel this year that raised the front of our robot up ever so slightly, & when we measured it, the bot was out of profile with the wheel in the down position. We had to cut our frame depth (front to back) a bit so that when it leaned back it was still in profile.
Just one more thing to consider.