PDA

View Full Version : four wheel steering using S3003 servos



hank van buren
11-14-2006, 10:35 PM
Four wheel steering
I want to build a robot 4 wheel drive and 4 wheel steering and use Futaba S3003 servos I would appreciate to hear from people how worked on this kind of project before. Any information would be welcome. Thanks Hank

allanlane5
11-14-2006, 11:17 PM
The BOE bot uses two 'modified' Futaba servos ('modified' so they can turn continuously) and is a 'tail-dragger', so it uses differential drive to steer.

Next level up would be a 'front wheel steering' approach -- with two drive wheels in the rear, and a non-modified servo in front to position the 'steer'ed wheels. I've done this in Mindstorms, the control is a bit more tricky, because you no longer can turn in your own width like a differential steered bot. Instead you have to do 'y' turns like an automobile.

Next level up is 'front wheel drive' steering. Here you start to run out of room. You need some kind of flexible drive shaft, or universal joint. This is because the driven wheel has to be able to change direction. So you also need some kind of 'steering bar' to get the steering control.

Then we finally reach your "all 4 wheels steered AND driven". This is so complicated, I've never seen it done on the hobby level. If you could steer the front wheels as a pair, and the rear wheels as a pair, would that be sufficient? Maybe Tamiya has some hobby level gear you could use.

Franklin
11-15-2006, 12:36 AM
Easiest way to start is to mount wheels on continous rotation servos then mount those servos on regular servos and mount those to the chassis. These parts will help with the connections. www.lynxmotion.com/Category.aspx?CategoryID=73 (http://www.lynxmotion.com/Category.aspx?CategoryID=73)

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
- Stephen

Jon Keinath
11-15-2006, 01:51 AM
I have some pictures of my "Quadly" robot. It runs with the Javelin Stamp, and a PSC. The drive servos are modified for continuous rotation, and the steering servos are standard. I built the base out of masonite, and the brackets are made of oak. The servos are standard Hitec Servos.

Below is a link to my webpage that has some information about it....If you want to know more that isn't on there, I'll be happy to answer questions.
www.kettering.edu/~kein0105/robotics.htm (http://www.kettering.edu/~kein0105/robotics.htm)

-Jon

Special_K
11-15-2006, 11:16 AM
I used the Lynxmotion Servo Erector Set and some of the Vex parts to make my bot. here are some picts of the frame as I was building it. if you want to know exactly what Lynxmotion parts I used I can send you a list.
with this set up the bot can make an L shaped turn.

Post Edited (Special_K) : 11/15/2006 3:29:00 AM GMT