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CoooL
06-26-2010, 02:55 PM
hi guys.. im new here..

first of all VERY nice forum. Im Danish, so excuse my english. :D im 23 years old, and have always been in to technic and computers etc.

ive started a tracked rover project (my first ever robot project), driven by two 24v wheelchair motors.
the chassis for the robot i build from 20 mm square tubular steel.

the four "surface" wheels on each side will be mounted on 2 arms that has springs and dampers. To be able to cope with very rough terrain.

it will be (remote)controlled by a laptop computer over a wireless connection. with a Vellemann K8055 board. The server and interface is written in python and connecting thru sockets. The interface uses the Pygame module for the GUI. Future plans is to make it autonomous,

i will post some images ASAP. Im far from done yet. The frame is build, i still need to build the suspension arms and much more, get some decent H-Bridges, Batteries, sensors, build drive wheels, tracks and so on.


I Really hope you guys like my "newbie" project.

CoooL
06-27-2010, 06:47 AM
some pictures:
http://www.coool.dk/robot/1.jpg
The rover. The black wheels are 100 mm (aprox 4 inches) in diameter and the white one is 160 mm (6.25 inches)

http://www.coool.dk/robot/2.jpg
The Front (white) wheel will be on a swing arm with a spring on to hold tension on the track when the road wheels (black ones) suspension negotiates differences in the terrain. (drawing for a-arms at the bottom)

http://www.coool.dk/robot/3.jpg
From the front

http://www.coool.dk/robot/4.jpg
One of the two wheelchair motors. 24v 6A @ 110 RPM

http://www.coool.dk/robot/5.jpg
One of the BIG pneumatic rams that might go on the rover.

http://www.coool.dk/robot/6.jpg
The belts that will have some kind of rubber attached to have contact with the ground. and some angles on the sides to hold it on the wheels.

http://www.coool.dk/robot/7.jpg
Mini diamond plate for the sides and bottom of the robot.

http://www.coool.dk/robot/8.jpg
Cooling fans for the speed contoller and laptop that will be mounted in the belly of it

http://www.coool.dk/robot/9.jpg
The a-arm for suspensionin front and under. 140 mm wide between the mounting points, to avoid buckling under harsh driving.


The pneumatic rams will be used for a heavy duty manipulator arm. The arm will have the posibility to have different things attached to it for different purposes, like lawn mowing, metal detection, grabbing things or what ever is needed. the whole arm assembly will be easily (de)attachable.

jes1510
06-27-2010, 11:31 AM
Nice work! Keep this thread updated with the build progress. It looks like you could just about ride in that thing.

CoooL
06-27-2010, 01:39 PM
i will keep it updated.. have been a bit slow lately with progress.. funds has to be there to build it. the biggest posts to build it has been the motors off ebay. the next two will be the 6 springs/dampers for a scooter around 20$ a pop.. haven't been able to source others that looks up to the task.
and then i need two decent h-bridges. I've looked at the MD-03 here (http://www.robot-electronics.co.uk/acatalog/Motor_Controllers.html).. But dunno if its a overkill, considering the motors only draw 6-7 amps?? any other suggestions for a h-bridge (preferably within europe, due to customs and taxes i if order from outside europe ex. USA) my Vellemann board has 2 PWM outputs.

http://media.thg.dk/DAT/pic/m/56103032001.JPG

i probably could ride it yes.. :D i hope it'l handle a big payload...

darkback2
06-27-2010, 03:52 PM
One thing to be careful of is how wide vs how long your robot is. You probably already thought about this, but the longer your robot is the more each track will resist turning. Not sure from the looks of things of the ratio of your bot.

Also I love my Vantec electronic speed controller. It runs two motors and does the mixing for you. You can also disable that and use each side independently.

Looking good so far.

DB

CoooL
06-27-2010, 04:08 PM
It Will be aprox 110 cm long depending on the track tension. And 65 cm wide. A rough guess is that 75 cm track Will touch the Ground.. So i hope it will work...

Ill have a look at that tomorrow thank you very much for the reply ;)

zoomkat
06-27-2010, 04:41 PM
the next two will be the 6 springs/dampers for a scooter around 20$ a pop.. haven't been able to source others that looks up to the task.
I'd purchase those later, as there are more important things to spend your $$$ on. Just use simple solid axles until you get other more important issues resolved.

darkback2
06-27-2010, 05:08 PM
I'm not sure of your payload, but I've used 20 pound lawn mower springs in the past... $3 or so for 2 at home depot.I use some one inch steel square tube pipe and 3/4 inch aluminum to make my own shocks. seams pretty compliant, and depending on the weight of your bot you can just use more.

DB

CoooL
06-28-2010, 02:02 PM
I'm not sure of your payload, but I've used 20 pound lawn mower springs in the past... $3 or so for 2 at home depot.I use some one inch steel square tube pipe and 3/4 inch aluminum to make my own shocks. seams pretty compliant, and depending on the weight of your bot you can just use more.

DB

Got some pictures of those shocks? for inspiration :veryhappy::D

CoooL
06-28-2010, 02:56 PM
i hope these pictures gives a better idea of how its gonna look..
http://www.coool.dk/robot/10.jpg
Sideview

http://www.coool.dk/robot/11.jpg
Detail view of suspension

http://www.coool.dk/robot/12.jpg
Bottom

darkback2
06-28-2010, 03:17 PM
http://forums.trossenrobotics.com/gallery/files/1/4/9/9/shock1.jpg
http://forums.trossenrobotics.com/gallery/files/1/4/9/9/shock2.jpg
These are two early examples.

I used an angle grinder and a cut off wheel to cut the slots that the bolt slides back and forth in. I use 1 inch square tube with a cap welded onto the end. You can also just drill a hole in the end and put a bolt through so that the spring can't shoot out.

The springs when completely un-compressed are about 4 inches long, and when fully compressed are about an inch. So you could hypothetically get 3 inches of travel out of them. I haven't had too much success with anything other than the 20 pound springs.

In later versions I got the outer 1" square tube pile down to about 5 inches long, The 3/4" aluminum pipe can be as short or long as you need to get so long as it sticks out the end enough for you to attach to it.

If you need I could probably render it in google sketch up or something...Hope this helps though.

DB

CoooL
06-28-2010, 03:36 PM
Very nice thank you.. Very much apriciated..

darkback2
06-28-2010, 03:52 PM
http://forums.trossenrobotics.com/gallery/files/1/4/9/9/shock.jpg
Here is a quick sketch up... Hope this helps.

DB

CoooL
07-03-2010, 10:32 AM
Ive been looking at the "SyRen 25A regenerative motor driver" are they up to the task you think?