### Author Topic: SPIRAL NAVIGATION OF A MOBILE ROBOT  (Read 1443 times)

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• Beginner
• Posts: 2
##### SPIRAL NAVIGATION OF A MOBILE ROBOT
« on: August 28, 2012, 04:35:36 AM »
Hello ,

I have a Mobile robot with two rear wheels. These two wheels are actuated using a single motor. I can give a forward speed and a reverse speed and a robot heading.

I am programming a spiral motion for the robot i.e. an archimedean spiral using Matlab. I really don't know how to do this. Can any one suggest me..!!

Thank you very much.

#### jkerns

• Robot Overlord
• Posts: 270
##### Re: SPIRAL NAVIGATION OF A MOBILE ROBOT
« Reply #1 on: August 28, 2012, 07:13:27 AM »
How does it steer? Do you steer a front wheel(s) or do you have some way to make the drive wheels turn at different speeds using one motor?

For your spiral, you need to calculate the radius at each moment of time and from that determine either the difference is wheel speeds or the steering angle.

For differential drive, calculate the different circumferences for the inner and outer wheels - that gives you the different speeds.

For steering by turning wheels, draw yourself a picture of how it turns and you should be able to sort out the trigonometry.  http://en.wikipedia.org/wiki/Ackermann_steering_geometry
I get paid to play with robots - can't beat that with a stick.

http://www.ltu.edu/engineering/mechanical/bachelor-science-robotics-engineering.asp