[shaiqbashir]

Hi Guys!

Hope u would be fine out there!

Well! im planning to make a robot. The drive mechanism that i have choosen for that robot is a Tri-Cyclic mechanism. That is two Big Wheels at the back, both of them will be connected with one single motor. SO there will be one motor driving two back wheels. Just like in a car.

There will be a third wheel in the front portion of the robot that will be used for steering purposes. Now i want to ask you that what are the known issues and problems with this type of drive mechanism?

WHat motor should i use for steering? Should it be Servo or a Stepper?

Is the steering motor needs to be powerful enough??

What could be different problems i can face in this mechanism?

Please tell me as soon as possible!

Take carez!

Good BYe!

[Al_The_Man]

You don't mention what weight and size the robot is, but one method is servo operating into a planetary gearbox above the front wheel, with the front wheel hung right below it, in a swivel fashion.
Al.

[mxtras]

Well - if both back wheels are driven on a common axle, I can see problems with steering. Most vehicles are driven through a differential - not a solid drive axle.

In a tripod arrangement, you could drive the single wheel and still use it for steering or drive both back wheels through seperate motors and steer via varying the speed of one or both motors.

How do the RC guys do it? DO they actually have differentials?

Scott

[shaiqbashir]

Well! my robot is around 1200 cm2 in area and is having a weight of 12 kg.

[erase42]

i have the heathkit hero one robot and it has 3 wheels. the two rear wheels are coasters and the front wheel steers 180 degrees and supplies drive power as well. nice setup zero radius turns eliminates need for differential. stable as well. rear wheels could then be moved or resized according to changes in your bot. i can send some pics of the set up if desired.

Ed

[shaiqbashir]

yeah most welcome plz! send me some pictures so that i can analyze your idea as well!

thanks in advance!

[erase42]

ok give me a day or so to dig him out, with the pics i may also be able to send copies of the actual construction instruction with breakdown of the little parts.

[Bloy2004]

ok give me a day or so to dig him out, with the pics i may also be able to send copies of the actual construction instruction with breakdown of the little parts.

Hi Ed,
We're still waiting for those pictures!

[erase42]

ok, its been difficult since all my cameras are at work and the robot is at home. however i just bought a new cam thats still here with the robot.
if i can get it to interface ill try to send some off today. if not today then surely tomorrow. i apologize for my general lameness i hate waiting for people and i kick myself for causing others to do the same.


Ed

[erase42]

ok here they are, if you have questions or want a different angle let me know. the one pic with the circle drawn on it is showing the steering stepper motor that is inside the robot. the drive wheel, its gearbox and motor mount directly to the output shaft of that motor.
only half managed to upload, ill try again in a new post

[erase42]

here is the rest