# How can I find the instantaneous directional vector of 3D dubins vehicle?

This topic is 774 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

http://www.et.byu.edu/~beard/papers/preprints/BeardMcLain__.pdf

I've figured out how to find out the instantaneous position of the vehicle.

But Will the direction be the delta of the current position and next position?

I am not sure, is there a reliable way to do it?

Of course, I already have the start direction and some ending directions

in the spirals and straight lines.

For example, when the vehicle starts at radian 4.7, with a left turn

can I assume at time 0, it is at 4.7 and at time 1, it will be at 4.6.....(left-handed system)

The elevation isn't taken into account anyways....

Thanks

Jack

Edited by lucky6969b

##### Share on other sites

If you're not taking the elevation into account, the direction would be the tangent line of the circle.  I'd have to poke around more on how you'd get the Yaw from a helix.

##### Share on other sites
It should just be the first-order derivative of the equation you use to get positions. There are online tools to do differentiation if your calculus is rusty :-)

##### Share on other sites
As a first approximation, take the positions at times t+0.001 and t, subtract them and multiply the resulting vector by 1000. This is an inelegant approximation, but it's really easy to implement and to get right. If you end up using a fancier method, you can still use the inelegant method to verify that your fancier code is correct.

##### Share on other sites

Re-Education.... :)

1. 1
2. 2
3. 3
Rutin
20
4. 4
5. 5
khawk
14

• 9
• 11
• 11
• 23
• 12
• ### Forum Statistics

• Total Topics
633655
• Total Posts
3013181
×