Gravity 2

Well, here we go ! Wednesday evening, January 8, WJ finally starts building his 2003 entry for the Dutch Robot Wars Series 3. This soon ? yes, I know, normally I start building robots bout a week before the event, but this time it will be different !!! Everything has to be perfect now. I have savaged a lot of parts from my 2002 entry Gravity, (yes, the 2003 entry's name is also Gravity) so starting out with the drivetrain wasn't that hard.

my workingplace

small, huh...

lots of robot parts

R.I.P.-ed bots

Rust in Pieces

Why start with the drivetrain? I like my robots to have a lot of ground clearance, so I don't get stuck on things like debris, the flamepit and the pit edges. So now I knew what ground clearance I wanted to have, I knew my weapon of choice was a flipper (why a flipper ? quickly disables an opponent without really destroying it). So, now I have all the parts, somewhere around here that is, I can place them together and make a design based on everything that needs to go in. Basic design: Full pressure flipper with a single ram, 2 Co2 canisters and drivable both-way up. At first I wanted to build the entire bot at the height of a cart-wheel, but this would leave me with a small space to put my ram in. So I decided to go for competition kart-wheels (=grip) with 125mm rubber wheels on top of them, for inverted driving. Also I had to keep in mind that the 2 Co2 canisters had to be easily accessible... I put the gearboxes (made by KOS) back together and set it up:

2 gearboxes

very well made

nice close-up

setup from side

setup from rear

Welded some steel together, and came to the conclusion that these short lengths of steel box section weren't the way to go, so I took them out and put some really long ones in. These new lenghts run from the front of the robot to the back, and there's 4 pieces of them. This will make the robot much more sturdy then welding pieces together. I welded the backside of the robot, and fitted the co2 bottles in. Like a glove :) Als removed the ball-rollers from Gravity1 and welded them into the new bot. Weighed the whole setup, and only 29 kilo's including wheels and gearboxes !!! The frame alone from Gravity1 was about 35 kilo's so this is quite good. The frame is in Mario's hands now, he's going to fit the custom made 100x180 high pressure ram. So next post will be in about a month time, so cu then.

show setup

looks good...

inc cross section

other side

only 29 kilo's !

Ok, I got the robot back from Mario, and with it all the parts I "requested". Mario already put the joints for the flipper in place, so now it was up to me to make it all look nice, and even more important, make everything work !!! first thing I did was bolt the high pressure buffertank in the robot, after that I welded the entire front of the flipper, and final action for today was drill and tap the holes for the 125mm full rubber blickle wheels, to make the robot invertible. When running inverted, I don't have lots of ground clearance, but hey, it still runs ...

Buffer tank

Big flip

good progress

It's invertible !

just another pic

Ok, ok, I know, waaaaay to long ago since I updated the build section. I did do some work in this long time of silence. Only big problem is : I didn't make any photo's of the work ! So I'll just have to stick to telling you what happend. I fitted some side-bars, as you can see in the first picture, to protect the side and the wheels of the robot. And it looks good too :) Fitted all the stuff in there, hooked it up and it worked ! Put a few pics of the finished robot underneath here. These pics were taken at Dutch Robot Games 2 in Rijswijk, Holland.


lining up 4 fight


flipper bent

going home...

At this very first live event I went to with the robot, a few things became clear : don't put the electronics of your burkert valves on backwards (the robot failsafed with the flipper opened, so on every transmitting error my flipper fired, doh ! Don't use metal springs to stop your 5000 kg ram, it wont work. If your robot is low, it can get under other robots, which is good !!! I put some videos of the flipper frenzy online, see below.

video 1
video 2
video 3
video 4

This was the first and last event for Gravity 2, it didn't win, so there's something wrong with it :) Savaged all the parts I wanted to use for Gravity 3 and dumped the rest... So, on to the next robot, Gravity 3 ! (click here)