# Society of Robots - Robot Forum

## Electronics => Electronics => Topic started by: neenah on March 11, 2013, 05:47:45 AM

Title: turning the vehicle left/right by 90 degrees
Post by: neenah on March 11, 2013, 05:47:45 AM
Hello,

I am working on unmanned ground vehicle project. I want to turn the vehicle right by 90 deg.

I have 4 stepper motors so how should the 4 motors rotate so that the vehicle turns right.

Title: Re: turning the vehicle left/right by 90 degrees
Post by: newInRobotics on March 11, 2013, 06:01:06 AM
Both side wheels rotate counter-clock-wise.
Title: Re: turning the vehicle left/right by 90 degrees
Post by: neenah on March 11, 2013, 06:31:52 AM
sorry i didnt understand.

motor 1     0-----------0  motor 2
|               |
|               |
|               |
motor 0     0-----------0 motor 3

you mean to say motors 0 and 3 should rotate counter clockwise?
Title: Re: turning the vehicle left/right by 90 degrees
Post by: newInRobotics on March 11, 2013, 06:40:25 AM
All right, to keep thing clear correct me if I am wrong - You have a robot which employs 4 wheel differential drive? If so, all 4 motors have to spin counter-clock-wise to turn to the right. How much they have to spin depends on radius of the wheels used and robot base length and width.
Title: Re: turning the vehicle left/right by 90 degrees
Post by: jwatte on March 11, 2013, 01:11:34 PM
And, to be clear: Counter-clockwise from the point of view of looking outside the robot, inwards towards each wheel.
Another way to put it: The wheels on the left side should rotate to drive forward, and the wheels on the right side should rotate to drive backward. Exactly how much depends on the wheel dimensions, material, ground material, and amount of slip.