Would this be a good antweight?

[Shakey]

I have decided to go for an easier design for haywire than the flywheel as I was having weight issues and also thought it would be better to have something for the non destructive (so just flippers and pushers) stuff and for practice.

It will have:
4 motors (I will try to link them sometime)- 2 per channel
Sabertooth 5x2 dual motor controller
7.2V LiPo
AR1600e Spectrum receiver
A servo (not sure what yet but I want it to be quick for the flip)
1-3mm Polycarbonate, 1-2mm Aluminium front

(front)

(back)

Just to note the servo is vertical not lying down to give it more clearance for the flipper over the motors and saber tooth. The rest of the robot will be very flat.

It should have nice pushing ability with fliping aswell. And looks to be under weight so far. What would a solenoid be like powering the flipper. Amd if a servo is better how to arrangee it? Direct link or other mechanism.

[Simon Windisch]

Hi there,

It looks like a good design, but I think you might be looking at 170g with four motors and a servo - you might want to check your sums.

Simon

[razerdave]

All that sounds good in practice but weight wise thats not going to work, and theres a good example of this: Terrorizer; its 4WD has the same sabretooth controller, 1 cell extra battery than you've said and 0.3mm Ti scoops on either end and 1mm polycarb te rest of it, no weapon on it, just a fast rambot, and its right on the weight limit at that.

Things I would suggest changing is have it 2WD for manouverability and to allow weight for armour, use one of peter W's boards rather than a sabretooth because its a lot lighter and no messy wiring for the weapon servo, plus it costs less than a Sabretooth, and you can get a 2g spektrum receiver (AR6300) that will plug right into pete's Option B63 board.

As for flipper attachment, I prefer the direct attachment method, but it does sometimes cause gears to strip, so I'd use a metal geared servo if you do choose to do that

[joey_picus]

I have to echo Dave's comments about weight - Jigsaw has a similar setup but even then with some lighter components (thinner 1 to 1.5mm armour, Peter Waller board instead of a Sabertooth and only 2 wheels) and it's right on the weight limit as well, I had to cut a huge chunk out of the base to get it under 150g.

Flipper attachment and servo choice...depends largely on how you see your final design ending up, Jigsaw has a linkage to the flipper from a Park HPXF but it's also front hinged so that was the best way to do it without having the servo in a really awkward position. You can more or less make any sort of flipper work - direct attachment, through a linkage, using a cunning system of miniature spaceships and cosmic winches - with enough tweaking of the design so it's really up to you I would go for a servo over a solenoid though purely because I can't recall ayn successful solenoid based flipper robots.

[daliad100]

Unfortunately, solenoids produce less force towards the end of their stroke as the air gap increases (or at the begining for a pull solenoid.)

It could work if you have a powerful enough short stroke solenoid and use a lever to increase the distance traveled. However, most solenoids that are powerful enough are far too heavy. So I'd stick with a servo.

[Shakey]

I just did a weight test on the parts:
Wheels (3g each) 12g overall - can have weight save.
Sabertooth 18g
7.2V 350mah 2 cell LiPo 23g
AR6100e receiver 5g
Motors (10g each) 40g
Servo Park HPX (will be upgraded sometime) 20g can have weight saving.

118g total
32g left for chassis and voltage regulator.

I can see how I would need some weight saving and one of Peter Wallers speed controllers and I can shave a lot of weight from the plastic on the servo.

Also thankyou for the advice so far.

[bitternboy]

You may have some trouble fitting all of the components above into a 4"inch cube. R of the O is (I suspect) too large at present and has pretty much exactly the components you have listed except for a Hitec HFS-05MS reciever and some Polulu Hp motors. Note this is without the servo so unless you cut down on chassis considerably you'll be having some trouble.

[Shakey]

You may have some trouble fitting all of the components above into a 4"inch cube. R of the O is (I suspect) too large at present and has pretty much exactly the components you have listed except for a Hitec HFS-05MS reciever and some Polulu Hp motors. Note this is without the servo so unless you cut down on chassis considerably you'll be having some trouble.

I reference you to the picture at the top of the page. The cutouts are actual size and they are on a 4" paper square so i have tested that part already.

BTW does anyone know how much peter wallers speed controllers way?

[peterwaller]

The controller specs can be found at
http://www.antweightwars.co.uk/Controllers.htm
It should be noted that they are sold as suitible for two motor drive only as per motor table http://www.antweightwars.co.uk/MotorSpecs2.pdf
Standard motor gearboxes up to 3 cells
HP and 12V motor gearboxes up to 2 cells

[bitternboy]

Not to be constantly find design faults or anything (cos I'd love to see this pulled off) but you may want to rearrange the components a little.
Now I'm not very good at talking about physics, but the problem at the moments looks like this:

When you have a 4 wheeled vehicle with "tank style" steering whereas wheels on the two sides of the vehicle work together, it's important that the distance between the wheels on either side is greater than or equal to the distance between the wheels on one side.



If this is not so, there will be a serious problem with the wheels rubbing and therefore decreasing the performance when turning (i.e. it will judder and loose traction). There's probably a theory or equation or something to explain it better but trust me it's important stuff.