Featherweight Database

[dudley_laver]

Featherweight Database

im currently building my featherweight at the moment and have changed design from pneumatic flipper to linear actuator crusher.
- making a razer style claw
- linear actuator in base of robot
problem
- making the straight movement into crushing power, at the moment it holds gently or drags claw backwards . Help needed . thanks

[dudley_laver]

Featherweight Database

will try and get picture on profile later to help

[woody]

Featherweight Database

Id make the claw and actuator assembly something like this .. +1>-------+2>C+2>.
where the --- is the actuator C is the claw and . is the claw pivot point.
Moving the actuator connection point up or down the back of the c (claw) will give you various jaw openings and crushing power.


(Message edited by woody on July 23, 2007)

[dudley_laver]

Featherweight Database

thanks for that idea, simular to dragons claw.
how does a razer style claw work then ?

[dudley_laver]

Featherweight Database

pictures of testing can be found on http://www.freewebs.com/snowshifterswww.freewebs.com/snowshifters ,this will give you an idea of what im trying to do.}

[grant_ploughbot]

Featherweight Database

Razers claw works almost the same but with the pivot point and the actuator conection swapped around. The simplest way to explain it would be to have a bar of some sort, put a pivot in the centre and push on the bottom. This would rotate the bar. All you need to do then is shape the bar to a curve, work out the best distance between the actuator and pivot and your well on your way to a razer type crusher.

[Kenny]

Featherweight Database

Flow! is nearly done so i thought i would post the specs.

Name: Flow!
Armour: 2mm Stainless
Chassis: the whole chassis is 16mm nylon the base is routered to 5mm to loose weight
Drive: Bosch 35s
Power: 2 x 7.2v 2.3ah race packs giving 14.4.v
Control: 2 x electronize and specktrum
Weapon: Full Pressure 60mm bore by 95mm stroke Square ram, fired by a burkert, fed by a 3 x volume buffer, from a 20oz paintball bottle.

[maddox]

Featherweight Database

Just to mention, as we dont have the weapon system of Hannibalito II anymore, I had a month to create a new weapon system.

Hannibalito III is a strange fish in our stable.

The ram is diminished from 61mm bore 80mm stroke to 51 mm bore 75mm stroke.
The drive, from the hugely overpowered Speed 900s on a sidewinder with 18V 3600mAh NiMh Sanyos goes to the feeble Speed 720 BB torques on a Scorpion XL on 2300mAh batteries.

In other words, its an efford to avoid Self OOTAs

[leorcc]

Featherweight Database

No it isnt.

[grant_ploughbot]

Featherweight Database

Mario, are you using the same inlet to your ram as H2?
If so H3 may well be a better flipper as theres less volume to fill up with the same flow

[leorcc]

Featherweight Database

there are 2 main reasons to the reduction in size and motors.

1: To get the weight down for more armour.
2: To reduce the forces on the parts in case of a miss.

Self OOTAs and other robots OOTA is still a very big possibility.

[maddox]

Featherweight Database

The inlet in the H III ram is sleightly bigger. From the bottleneck in the bottom of the ram of 8mm diameter to a full 1/2 inlet.
This constraint was set by myself in an efford to create a low profile, so a double sided driving robot was possible. We never did build H II as thus, as the wheels, and reduction became so big and heavy it couldnt fit in and leave weight for armor.

The force of the ram is lowered with 1/3 from 1500 kg+ to a mere 1000 kg

And Leo, dont tell all the secrets... I never mentioned the Unobtanium armor.

[grant_ploughbot]

Featherweight Database

Im not an exper on pneumatics, but i know a reasonable amount. I presume that because your force is 1/3 less (so volume will be 1/3 smaller) that you ram will now fire to a full stroke in 2/3rds of the time? In this case H3 should be throwing feathers much higher

[big_nipper]

Featherweight Database

Put simply Acceleration = Force / Mass, so the more force you have lifting the other robot the faster it will accelerate until it leaves the flipper arm, of course if the pneumatics dont generate that force because of the flow restriction, then it will reduce the force from that expected, there are some online calculators to work out how far in theory you can throw a robot, but in the end its simpler to just build the biggest ram with the highest flow possible in the weight.

[leorcc]

Featherweight Database

That is a fact. However there comes a point where it really becomes academic how much power you put in to it. Your robto and your opponents robot only weigh in at 12kg, so shoving them in the air with 250kg or 500kg at the point of the arm, unless you want to compare trajectories, both will do the job.