non-pneumatic "kicking" mechanism
 

what teams are attempting a "kicker" that is not a pneumatic in any way shape or form?

what will provide the power and how will it "reset" have you found it to be more powerful that pneumatics? :confused:

Re: non-pneumatic "kicking" mechanism
 

I can't say that the team has committed to using this, but one non-pneumatic mechanism that came out of the brainstorming was a shooter mechanism similar to those used in Aim High. Think of a wheel, maybe 6" in diameter, spinning fast. When it comes in contact high on the ball, it puts a heavy top spin on the ball, which then rolls away fast. Get the angles right, and maybe make that wheel move up or down a little and you can kick it into the air, or roll it fast enough that the Bump does the airborne part for you...

Re: non-pneumatic "kicking" mechanism
 

Actually, my team is trying something similar to that. We have a spinning roller attached to an arm which is pulled forward by surgical tubing. We been getting good results so far, hitting the ball at least twenty feet and over a bump. However when we just had the straight spinning roller to the ball, the ball went fast and far, sure, but it hit the bump and bounced off.

Re: non-pneumatic "kicking" mechanism
 

So far we've been looking at a sort of slide hammer design that relies on the surgical tubing. Initial calculations are very promising, but this thing will certainly need finger guards! The thought was to make a device with only a 12" stroke, but it would require 300 lbs of spring force!

Some revisions are in order.

Re: non-pneumatic "kicking" mechanism
 

1350 is planning on using a *censored* to *censored* a *censored*-*censored* kicker along a *censored* that will be *censored* with a Pneumatic 'device'. this is the only pneumatic 'device' planned for the kicker system.:cool:

I think that could be considered non-pneumatic:D

Edit:
hint:
AAAAABCCCCDDDDEEEEEGHIIIKKLLLLLNNOOPPPRRRSSSUW

Re: non-pneumatic "kicking" mechanism
 

Our kicker will have a mode that doesn't use pneumatics, but we will extensively be using pneumatic actuation in every part of the robot except the drivetrain. Shifters cost a lot of money. :(

Re: non-pneumatic "kicking" mechanism
 

A simple swing arm attached to a CIM does wonders. Not to mention that the strength is variable, because you can change the speed that the hammer swings at. Think croquet.

Re: non-pneumatic "kicking" mechanism
 

The spinning wheel is out (good thing, too). Now we have a more conventional 'leg' powered by latex tubing, reset with pneumatics.

Re: non-pneumatic "kicking" mechanism
 

Mind posting a video ?


~

Re: non-pneumatic "kicking" mechanism
 

We are doing something close to that except the CIM spins a wheel that is not directly connected to the kicker. The kicker is pretty much a wheel with a foot sticking off of it. when we put the CIM wheel against the kicker wheel the kicker spins forward and kicks the ball. The wheel is then retracted by a spring.

Re: non-pneumatic "kicking" mechanism
 

Don't wanna give too much away, but we will be using a sort of bell crank mounted to a large wheel to retract our kicker, and surgical tubing to snap forward

Re: non-pneumatic "kicking" mechanism
 

we are using surgical tubing w/ a window motor and clutch. however, the clutch part is a mess. that is all i will say...

Re: non-pneumatic "kicking" mechanism
 

heh....it's not an easy thing to design and build.

I'll let you know if we ever get ours working

Re: non-pneumatic "kicking" mechanism
 

We will be using a crossbow type linear device powered by surgical tubing. The front carriage with the kicker will be pulled back by a second carriage on a lead screw. Releasing a latch will separate the carriages and the kicker will fire.

Re: non-pneumatic "kicking" mechanism
 

Ours does anywhere from 2' to 35' :cool:

We used the T-box and a single aluminum tube with an L-bracket on the end. Took about 20 min to build :)

Re: non-pneumatic "kicking" mechanism
 

Since the only arrangement of elements with any structural integrity is the triangle, and since it is more efficient (less material) to apply and direct force via tension ---

Our kicker is an aluminum triangle "pendulum" made of tee-slot channel with gusset plates at corners and a "toe" on low corner for ball contact. Triangle's top corner clamps to 5/8 axle through ball bearings. At low corner of triangle is attached a 1500lb test 1/8 x 1/4 synthetic cable that runs through forward mounted pulley which turns cable rearward, toward bank of bungee cords, pre-tensioned to ~50LBS. Rear corner of triangle has strong travel stop cord attached to solid frame anchor point. It stops the kick at end of travel, and it sustains the minimum pretension force on bungees.

On its path rearward to the bungee group, the kicker cable passes through a winder plate that is driven by a geared down CIM motor to ~12RPM. Winder rotates 0-180 degrees in just over 2 seconds to shorten tension cable up to 12", depending on desired kick strength (bungee tension rises to ~120Lbs at max.). Kick is triggered by instant disengagement of winder cable from the winder plate using 2" of pneumatic cylinder piston travel to actuate the disengagement. The kick can be triggered at any point in the wind up cycle from 0-180 degrees. The trigger design is a very simple medieval-type concept and there are no other masses accelerated during kick, except the kicker & cable, and that is all I can say about it.

We are waiting to finish the gear box setup for the winder to confirm what level of wind torque it can hold while motor is de-energized. If de-energized motor allows winder to UN-wind, another system will be needed maintain the wind up tension/torque while waiting for the right moment to launch a kick.
Will confirm results of gearbox test when finished.

So far, our kicker has consistently placed shots within a 30" dia. circle at 35+ feet. We still need to "possess" balls well enough to maintain this level of accuracy during match play, and this remains the bigger challenge. We do expect to be able to consistently score two or more goals from far end in autonomous mode.
-RRLedford

Re: non-pneumatic "kicking" mechanism
 

Here you can see our kicker.

http://www.chiefdelphi.com/forums/sh...highlight=1860

Without pneumatic systems. Only a CIM motor with gear box!!

Re: non-pneumatic "kicking" mechanism
 

Our kicker is powered by surgical tubing right now, but for competition we will find something stronger. We pulll it back with a window motor, and we have this sort of locking ratcheting mechanism which we will release with another window motor. Our range is looking to be around 40 feet, but it's variable on how far back we wind up the kicker.

Re: non-pneumatic "kicking" mechanism
 

The team from Chile posted a good toughbox kicker video.

http://www.chiefdelphi.com/forums/sh...d.php?p=911126

Re: non-pneumatic "kicking" mechanism
 

You won't get much stronger than surgical tubing, but if you're looking for more repeatability, bungee cord exchanges a little force for more consistency.

Re: non-pneumatic "kicking" mechanism
 

Hi Chris,

I was wondering if you read this somewhere or if your team discovered it by testing.

Thanks.


~

Re: non-pneumatic "kicking" mechanism
 

I have read on Delphi that the spring constant of surgical tubing is very temperature-dependent. I've also heard from others' testing (at this time I don't remember who) that their surgical tubing powered prototype had issues with consistency.

Re: non-pneumatic "kicking" mechanism
 

OK thanks. Just wondering, did either of these sources compare the consistency of surgical tubing to bungee cords?


~

Re: non-pneumatic "kicking" mechanism
 

I'm not so sure that the use of bungee cords sacrifice force when compared to surgical tubing.
You can easily make up for it by applying more/different bungee cords to achieve the force you are looking for. If consistency and durability are better with the bungees, its a no brainer, right?

Re: non-pneumatic "kicking" mechanism
 

Our kicker is going to be a large spinning blade/paddle thing. We will be able to adjust the speed/turn it off at will, allowing us to control the ball how we want to. Our tests give us about 10-15 feet, but we are changing the kicker mechanism now to have a larger paddle and possibly 2 motors.

Re: non-pneumatic "kicking" mechanism
 

If.

The veracity of the premise has not yet been established.


~

Re: non-pneumatic "kicking" mechanism
 

Do the spinning paddles/blades extend outside a vertical projection of the frame perimeter?


~

Re: non-pneumatic "kicking" mechanism
 

Just curious: why don't you just double-up (or triple-up) the tubing? That will make it twice (or three times) "stronger".


~

Re: non-pneumatic "kicking" mechanism
 

Yeah exactly. I guess one of our team members read somewhere on CD about harpoon gun tubing so now one of our mentors plans to get us a few different diameters of the stuff so we can figure out what works best. There are a lot of stretchy materials to use, and surgical tubing is probably not the ideal material.

Re: non-pneumatic "kicking" mechanism
 

The spinning wheel is in! We call it the spinning tounges of death!

http://cms.team639.org/node/113

Re: non-pneumatic "kicking" mechanism
 

We finished the transmission for ours today, now we just have to build the actual kicker. It sounds like we aren't the only ones using a pnuematic clutch system. We also have a worm gear system as well for variable positions/tensions.

Re: non-pneumatic "kicking" mechanism
 

Guess what? Spearguns and slingshots use "surgical" (latex) tubing.

"Surgical" (latex) tubing is ideal for these applications.


speargun and slingshot tubing


~

Re: non-pneumatic "kicking" mechanism
 

Disregard the previous post, pneumatics are back in
design
fail
modify
evolve
crash
burn
rise from the ashes
etc.

note: i'm totally making that my new signature

Re: non-pneumatic "kicking" mechanism
 

we got our clutch working. all it needed was a bigger pneumatic to disengage it! and some grease.

it kicked ~30 ft at max power.

hint on our clutch- a poor gen2 tranny got extreme modded, andy baker would either laugh or cry...

edit- what the heck, ill say more:

what we did:

removed high gear from genII to make the secdond speed nuetral

dremeled down dogs so they have 30 degree edges (make it so crowbar is not needed to shift)

modded plates and shafts to accept a window motor.

upgraded to a beefier piston.

now it works great. we chained it to an 8" performance wheel as a spool. and the kicker is powered by 2 bands of surgical tubing.

Re: non-pneumatic "kicking" mechanism
 

We're using a linear motion to kick the ball to keep it compact (non-pneumatic). We're still aiming to fit under the tunnel.

Re: non-pneumatic "kicking" mechanism
 

Oh sorry yeah I guess I meant the surgical tubing in the kit, because it varies with temperature and isn't really strong enough for our kicker since we don't want to use like 4 strips of them. We would rather have one stronger piece of tubing or bungee.

Re: non-pneumatic "kicking" mechanism
 

I know I don't have any sources on hand right now, and I'll find some later.

Surgical tubing is generally the most powerful springy stuff per length of material you can (cheaply) get. I recall a Mythbusters episode where they load tested various springy materials and surgical tubing outperformed bungee cords of various lengths by a lot. In Overdrive it was pretty much the perfect material, since you only needed to get the ball somewhere over 6 feet high and this far, and other than that it didn't really matter how hard you hit it once you got past the minimum threshold for success.

Springy material is limited by the amount it can stretch without binding or breaking. A good, safe number for surgical tubing is about 5 times its normal length if I remember correctly from random testing. Surgical tubing wears over time and with repeated use which makes failure easier over time as well. I don't know as much about bungee cords, but material deformation is less of a concern as far as I am aware.

Considering that for many kicking styles, shot distance tolerances may only need to be within several feet of the target distance depending on your goals, surgical tubing may work for you. My team has prototyped with surgical tubing with success. Many long range kicks may just need to "get in the zone" rather than in the goal, and the range of force imparted on the ball that will get it in the goal (lowest being barely rolling in, highest being barely not bouncing out) is surprisingly large. Play with the math and see what you get.

http://www.primelineindustries.com/tools.html has a surgical tubing spring calculator assuming ideal (new) tubing at room temperature.

Re: non-pneumatic "kicking" mechanism
 

We are having a lot of success using latex tubing for our non-pneumatic kicker. We should have the ability to adjust the tension and therefor the 'kick' strength. Using a cim motor we can constantly put tension on the tubing then allow it to spring back. We even worked it out so that it resets in just over 2 seconds

http://www.youtube.com/watch?v=30-gyhhBQ7A

we need a better video and I will post one ASAP. The only delay is moving the kicker from the test platform to the drive base

Re: non-pneumatic "kicking" mechanism
 

Yes, using one larger piece would make a cleaner-looking design.

But your concern about temperature seems unfounded. "One stronger piece" of latex tubing will have the same temperature properties as 4 smaller pieces. And "bungee" cord material varies with temperature as well. For the tiny temperature differences between competition venues, there should be no noticeable difference between the two.


~

Re: non-pneumatic "kicking" mechanism
 

Hi Rob,

I saw your video. Nice kick.

Couple of questions:

Do you use the motor to hold the kicker in the kicking position or do you use some sort of latch?

When you release the kicker, is the motor still connected? Or do you have a mechanism to disconnect it so that it doesn't get back-driven?


~

Re: non-pneumatic "kicking" mechanism
 

Found the post about temperature for you: http://www.chiefdelphi.com/forums/sh...22&postcount=9

Also keep in mind you can adjust tension in a well designed system throughout the day, so you can make fine tuning adjustments before each match when the venue temperature changes.

Re: non-pneumatic "kicking" mechanism
 

Isn't there a temp sensor somewhere on one of the sensors that you could use to calibrate your shooting distance vs. temperature? then it would all be automatic.

(because programmers never have enough work to keep them busy)

Re: non-pneumatic "kicking" mechanism
 

Hi Chris.

Thanks for the link. The anecdotal information it contains may inspire some teams to go do a little research about the material properties of elastomers used for storing potential energy for kicking, and that would be a good thing (learning!). Maybe a team or two will even run some simple quantitative experiments and post the results - like hanging a 10 pound weight on the end of a piece of surgical tubing and measuring its stretched length at room temperature, then taking it outdoors in the freezing cold and repeating the measurement. Then do the same with a "bungee cord".

As for the relative temperature-behavior merits of bungee cords vs surgical (latex) tubing, which is what we were discussing, I doubt that even a 20 degree change in room temperature would make "surgical tubing" change its behavior noticeably more than a "bungee cord"... especially if it's a bungee cord made with latex rubber!


~

Re: non-pneumatic "kicking" mechanism
 

I will post a better view of the kicker most likely tonight or tomorrow. The kicker is not held in a kicking position so no latch is needed.
A sprocket with a pin at the outter radius pulls the arm around and stretches the tubing. Once the sprocket turns 180degrees the pin is no longer in position to hold the arm back and the tubing snaps back and swings the arm.

Also through McMaster-Car there are many thicknesses for the tubing. I do not know but I wonder if tubing with a wall thickness of 1/4" is still affected by temp to any noticable degree (Within normal temparatures for inside ofcourse)

Re: non-pneumatic "kicking" mechanism
 

It could also be used to sense when hell freezes over :rolleyes:

Re: non-pneumatic "kicking" mechanism
 

I see. Your earlier post mentioned something about being able to adjust the tension and I mis-interpreted that as meaning you could adjust the tension of the kick during a match.


The temperature effect would be an intrinsic property of the material itself (latex), not the wall thickness.

If you are concerned about temperature, you could run a very simple experiment. Hang a 10 pound weight from a section of surgical tubing and measure the stretched length at room temperature. Then go outside in the cold and repeat the experiment (after letting the tubing cool down of course).

You can then very easily interpolate these results to the range of temperature differences you think might be reasonable to expect in the competition venue. Knowing the spring rate of the section of tubing you used for the test, you can calculate the expected change in force.


~

Re: non-pneumatic "kicking" mechanism
 

Adjusting the tension is a completely different system. The motor pulls the arm back and allows it to swing. A separate system will control/adjust tension.

Re: non-pneumatic "kicking" mechanism
 

Nice approach. Different from others I've seen so far.


~

Re: non-pneumatic "kicking" mechanism
 

Take a look at this. (There are three pictures following, just click on the right side of the pictures.)

As the wheel turns, the lone pin locks against the offset link, forcing it to rotate with the wheel (rather than just pivot). When the link hits the "12-o'clock" position, the pull to the right causes it to spring back very quickly. (NOTE: The surgical tubing is there to provide resistance for this demonstration. In final design, it would be a direct link to the kicker, which itself would be propelled with surgical tubing.)

Re: non-pneumatic "kicking" mechanism
 

What are the material limitations in order to strike the ball

Re: non-pneumatic "kicking" mechanism
 

Mister I,

That is a GREAT idea for a kicker. Elegantly simple, yet surprisingly complex.

Dang, that sounds like a sommelier...

We have circled all around that design and whiffed, but you guys hit the target dead on.

Nice job.

Re: non-pneumatic "kicking" mechanism
 

seems familiar....:p

http://www.chiefdelphi.com/media/photos/31539

Re: non-pneumatic "kicking" mechanism
 

This is the same system I was explaining (or trying to) it works very well

Re: non-pneumatic "kicking" mechanism
 

I wonder if this design could be set up to provide a strong kick when running the motor one direction, and a weaker kick when running it the opposite direction?

let's put on our thinking caps :)

Re: non-pneumatic "kicking" mechanism
 

That's an easy one! The two designs we considered were a pneumatic one, which we're using, but one could also make a quick-return 4-bar linkage driven by a CIM or FP, or two FP, that would swing quickly in one direction and slowly in the other. Simple in concept, but more difficult in application.

Re: non-pneumatic "kicking" mechanism
 

A little hint at our design with no pneumatics:

This

And This

And This

Re: non-pneumatic "kicking" mechanism
 

valve springs from a car could easily do that

Re: non-pneumatic "kicking" mechanism
 

Imitation is the sincerest form of flattery, and yes, that picture is where we got the original idea from. (I just couldn't recall "1625" when I made the post yesterday.)

Re: non-pneumatic "kicking" mechanism
 

We posted our kicker on youtube

http://www.youtube.com/watch?v=fhM-N4a_O-Q

the quality is not the best but it shows that same concept that is being discussed. The spring tension is relatively low for this test. With a higher tension (more tubing or attaching ther tubing further back) we can get more distance.

Re: non-pneumatic "kicking" mechanism
 

We made a prototype kind of like that, but realized that controlling it would be very difficult...because we want to be able to hold the kicker back so that we can control the ball (have it at the front of the robot while driving around), then be able to kick it. Getting the motor to stop at the top of the rotation looks to be challenging.

Re: non-pneumatic "kicking" mechanism
 

If you put a servo-controlled barrier in the way of the pin, you can keep it from inadvertently getting to the point where the kicker linkage is released.

Re: non-pneumatic "kicking" mechanism
 

The time to kick is not very long so we just stop the motor after it kicks. Trying to put the motor in the exact position does not seem neccessary when we are moving around. When the kicker is not kicking it is out of the way.

Re: non-pneumatic "kicking" mechanism
 

We plan to use a rotary crank to charge the kicker spring. The crank wheel will be a sprocket with the teeth ground down to a ratchet profile. It will be driven by a crank with a pawl at the end. Therefore, it is only powered when the driveshaft rotates in one direction. At the other end of the same power shaft, we will have another pawl and ratchet device oriented the opposite direction and connected to a release and winch for lifting during the finale. The shaft is powered by the 5th CIM and driven via a non-backdrivable worm gear.

Rotate the drive motor one direction to power & fire the kicker, run it the other direction to deploy and power the lift.

The prototype seemed to work well. Should have the real thing done in a few days. We'll see how that one does...

We have a 30" wide capture & kick zone. It is uses a linear motion, "T" shaped, plunger hitting a wide, hinged "flap". We don't intend to do full-field-on-the-fly kicks. We think it will be important to acquire, aim, and kick (over at least one bump) as fast as possible.

Re: non-pneumatic "kicking" mechanism
 

How does your software know that the motor has just kicked so that it can stop the motor? Do you have some sort of sensor signal?


It's hard to tell from the low-res video, but it looks like the momentum of the kicker mass carries it outside the frame perimeter to kick the ball, and the kicker's "rest" position is somewhat "retracted" from the full extension of the kick. Is that correct? If so, that's a very interesting design... all the kicking energy comes from the kinetic energy of the mass (no residual assisting spring force on kicker at point of impact). Please set me straight if this is incorrect.


~

Re: non-pneumatic "kicking" mechanism
 

sounds great! We might try the flap thing....any hints about it?

Re: non-pneumatic "kicking" mechanism
 

We are experimenting with sensor to help determine when a ball is in position. But after the ball is kicked the driver just turns it off. The cycle time for the kicker will be >2seconds so if a few extra kicks happened it is no big deal(No penalties). When a ball is in position again we casn just turn on the kicker. As of right now the wait time of up to 2 seconds does not seem to be a problem. It seems to me at this point putting a sensor on to stop the motor would be doing it just to do it (which isn't a bad thing really).

Re: non-pneumatic "kicking" mechanism
 

Wow that is impressive. will you post a pic/video when it is finished?

Re: non-pneumatic "kicking" mechanism
 

It is about 26" wide and will be 1/4" lexan with weight reduction holes (right now it is thin plywood). The hinge (across the top) is about 9" off the floor. The bottom is about 2" off the floor. It has an "L" shaped cross section. The bottom leg of the L is about an inch long and is the "toe" that provides loft. The plunger contacts the back of the L about half way up. It has about 5" travel, half before contacting the flap. So far, it is powered with surgical tubing. We are flying the ball about 15 feet with about 3 feet loft.

We hope have the rest of the final hardware done and installed early next week. We'll try to post pictures or video - but only if it works right!

Re: non-pneumatic "kicking" mechanism
 

Going back to the original question, we abandoned pneumatics early on as not be fast enough to get full range kicking. I have a nice idea for getting a variable kicking range from a pneumatic cylinder, but we will not be trying it this year. We also gave up on the surgical tubing as not having enough pull. Perhaps we should reconsider with more strands or thicker tubing? We are currently using steel extension springs connected to the top of the kicker, eliminating the need to have something whip around a pulley at kicking speeds. We are planning on a CIM powered winch to pull the kicker back a variable distance and then a -censored- to release it.

Mike

Re: non-pneumatic "kicking" mechanism
 

We finally got our mechanical kicking system going, sort of. But the plan is to use pneumatics to release it, unless we can come up with something else (linkage on a window motor is the other likely candidate).

http://www.youtube.com/watch?v=rId6Lnw-Hl4

This is the first time we got it working, and we need to figure out the control system, work on the "pulley", and install the release.

Comments welcome!

Re: non-pneumatic "kicking" mechanism
 

Here is ours
cam stile o yeah lol.

http://www.youtube.com/watch?v=Sfc7erbtuoE

Really love it squirrel. Are you using pneumatics some place else? Maybe you could bolt it to a larger sprocket and open it with a motor to save the weight if not.

edit: My bad didn't read it the whole way through lol.

Re: non-pneumatic "kicking" mechanism
 

http://www.chiefdelphi.com/media/photos/34748

Here is a picture of the 1918 quad drive as of Feb 8. The cable, release, and routing mechanism are not in place yet. We will use a more strands of tubing and there will be a limit switch to hold the firing device at the ready. As shown, the bands are about 1/3 charged.

Re: non-pneumatic "kicking" mechanism
 

Very well done multi-functional design . We are also doing similar heavy gear down tension winder, that will double as our lifting winch too.
Have you found that you really need to use the dog sprocket to prevent max tension from causing wind back of gearbox (when motor de-energized)? We have a big sprocket if we need it, but I was hoping 200+:1 ratio geardown would make it unnecessary.
-Dick Ledford

Re: non-pneumatic "kicking" mechanism
 

The ratchet mechanisms ("dog sprocket"?) aren't there to prevent back-driving. They allow the same drive motor/gearbox to power two separate devices, depending on the direction of rotation. The ratchets are oriented in opposite directions. The worm drive gearbox (Dayton 15:1 unit we bought through Grainger) prevents back-driving.