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NxRLab / ModernRobotics

Modern Robotics: Mechanics, Planning, and Control Code Library --- The primary purpose of the provided software is to be easy to read and educational, reinforcing the concepts in the book. The code is optimized neither for efficiency nor robustness.
http://modernrobotics.org/
MIT License
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wrong implementaiton of inverse kinematics, in the #25

Closed ertosns closed 5 years ago

ertosns commented 5 years ago

I think there is a bug in the IKinBody, and IKinSpace, in the calculation of Vb as TransInv(T) T, shouldn't Vb matrix = TransInv(T) derivative(T) T = [ R P; 0 1], while derivative(T) = [ d(R) v; 0 0], the they can't equal each others, the space implementation exist in the three languages!

HuanWeng commented 5 years ago

Hi, I don't think there's a bug. we use the numerical algorithm described in Section 6.2.2 of the textbook. Here we use the twist Vb to represent a motion, assuming it follows for unit time.

ertosns commented 5 years ago

right, that answer it.