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karlkurzer / path_planner

Hybrid A* Path Planner for the KTH Research Concept Vehicle
http://karlkurzer.github.io/path_planner/
BSD 3-Clause "New" or "Revised" License
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The problems of choose of dx dy dt. #29

Closed zhangxingyu1206 closed 4 years ago

zhangxingyu1206 commented 4 years ago

hi, @karlkurzer Many thanks for the nice code of your contribution. The step parameters: // R = 6, 6.75 DEG const float Node3D::dy[] = { 0, -0.0415893, 0.0415893}; const float Node3D::dx[] = { 0.7068582, 0.705224, 0.705224}; const float Node3D::dt[] = { 0, 0.1178097, -0.1178097}; when the vehicle driving forward and turn left, dx ,dy and dt should be positive.But,in the situation i=1, the step parameters dy is negative. Can you provide some reasons of doing so?Thank you very much.

karlkurzer commented 4 years ago

when the vehicle driving forward and turn left, dx ,dy and dt should be positive.But,in the situation i=1, the step parameters dy is negative. Can you provide some reasons of doing so?Thank you very much.

I am not sure why you think that this needs to be the case. It depends on the orientation of your coordinate system. In this case the coordinate system is defined, in this case the axis are flipped.

zhangxingyu1206 commented 4 years ago
fig1

Acoording to your defination of [dx dy dt], I plot the figure. No mater what kind of coordinate system, when the dx is positive and dy is nagative, the dt should be negative. But, in the figure, dt is positive,the the position for a driving car is not possible. In my opinion, the [dx dy dt] is shown below.

fig2
karlkurzer commented 4 years ago

I see - without looking into the code I'd assume, that the heading is also flipped (clockwise). That would be the only option, right?

zhangxingyu1206 commented 4 years ago

In your coordinate system,the heading theta increment is positive when the rotation direction is clockwise?

karlkurzer commented 4 years ago

That's a guess - it's been four years - so I am not entirely sure in what way I defined the coordinate system and the positive direction of rotation. Sorry for the inconclusive answer.

EthanCodesss commented 3 years ago

In your coordinate system,the heading theta increment is positive when the rotation direction is clockwise?

Hello! How to compute the value of dx, dy, dt? I don't understand why [0.705224, 0.0415893, 0.1178097]. Thanks for help!