how to plot an arrow given yaw/pitch/roll

Art
2015 8 4
2 个回答
回答已采纳
更新时间：2018 5 25
25 次查看（30 天）

0 个投票

What's the easiest way to plot a simple arrow of arbitrary dimensions given a starting position (x,y,z) and euler angles (roll,pitch,yaw)?

请先登录，再回答此问题。

 采纳的回答

Mike Garrity
Mike Garrity 2015-8-5

2 个投票

Consider the following simple example:
pt = [0 0 0];
dir = [1 0 0 1];
h = quiver3(pt(1),pt(2),pt(3), dir(1),dir(2),dir(3));
xlim([-1 1])
ylim([-1 1])
zlim([-1 1])
If we look at h, we'll see that it has properties named UData, VData, and WData.
h =
Quiver with properties:
Color: [0 0.4470 0.7410]
LineStyle: '-'
LineWidth: 0.5000
XData: 0
YData: 0
ZData: 0
UData: 1
VData: 0
WData: 0
This are the components of the vector. To change the direction, we want to transform those. The makehgtform command will give us a transform matrix for a set of rotations. We can use that to calculate new values for the UData, VData, and WData properties.
We can use it like this:
xfm = makehgtform('xrotate',pi/3,'yrotate',pi/5,'zrotate',pi/2);
newdir = xfm * dir';
h.UData = newdir(1);
h.VData = newdir(2);
h.WData = newdir(3);
You may have noticed something odd here. The vector dir is a 1x4 vector even though we've only got 3 directions. The reason is that makehgtform returns a 4x4 matrix. It does that so that it can support translations. You don't care about translations in this case, so we can ignore that.
To animate this, we'd do it in a loop and add a drawnow:
for theta = linspace(0,pi,64)
for phi = linspace(-pi,pi,64)
for psi = linspace(0,2*pi,64)
xfm = makehgtform('xrotate',theta,'yrotate',phi,'zrotate',psi);
newdir = xfm * dir';
h.UData = newdir(1);
h.VData = newdir(2);
h.WData = newdir(3);
drawnow
end
end
end
You may need to fiddle with the order in which you give the rotations to makehgtform. You'll see various orderings referred to as "Euler angles". The help for makehgtform will show you some other things you can do with it, such as the axisrotate option.

1 个评论
显示 -1更早的评论 隐藏 -1更早的评论

Art
Art 2015-8-12
Mike, I have a follow up question you may be able to answer:
If I were plotting this arrow on Matlab's Globe model, I would need to find the local U/V/Wdata at the lat/long/alt of the arrow starting point (I think?). Then I would use this as the arrow's starting "dir" in your above example, prior to doing the desired theta/phi/psi rotations.
In other words, the X/Y/Z positions I have are in ECEF coord, and I'd need to first rotate the initial arrow vector to point due north in the local NED frame, then rotate again per your example.
I can convert the X/Y/Z to Lat/Long/Alt, but how can find initial north pointing U/V/Wdata at any point on the earth given lat/long/alt?

请先登录，再进行评论。

更多回答（1 个）

Art
Art 2015-8-6

0 个投票

Thanks everyone for the suggestions! And thanks Mike Garrity for the clear, concise and exampled description, always a plus for me. After playing around with all suggestions, yours was exactly what I needed.

2 个评论
显示 无 隐藏 无

Joel Sande
Joel Sande 2016-4-12
Hi, How to do this from 1 point pointing in 3 different directions ?
zhaozhong chen
zhaozhong chen 2018-5-25
a late answer. Just type
h = quiver3(pt(1),pt(2),pt(3), dir(1),dir(2),dir(3));
%from the first answer and then
%then create two dir, dir 2 and dir 3
hold on
h2 = quiver3(pt(1),pt(2),pt(3), dir2(1),dir2(2),dir2(3))
h3 = quiver3(pt(1),pt(2),pt(3), dir3(1),dir3(2),dir3(3))
hold off %so you'll have 3 directions from the same points
xlim([-1 1])
ylim([-1 1])
zlim([-1 1])

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Programming 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by