Inverse Kinematics of a Open-loop chain (SCARA robot arm)

• 09-30-2020
Inverse Kinematics of a Open-loop chain (SCARA robot arm)
Hello,
This is my first post, and I need to know how to solve the IK problem for a kinematic chain with 3 rotating links/joints;

(JOINT)--------(JOINT)---------(JOINT)--------[END EFFECTOR]

And if there is a good visualization and schematization tool that I can use.
It's for a class project.
• 10-20-2020
jwatte
Re: Inverse Kinematics of a Open-loop chain (SCARA robot arm)
The question is how many degrees of freedom each joint has, and how many degrees of freedom you want to solve for the end effector.
If you have only three degrees of freedom total, and only need position, not orientation, for the end effector, then the problem has zero, one, or two solutions, corresponding to a quadratic equation.
You typically configure the first point to point the rest of the effectors at the end effector in a plane (using atan2 to solve for the angle) and then use "two-bone IK" for the other two joints to attempt to reach the position projected to that plane (this is where the quadratic equation comes in.)
• 08-16-2021
mcardoso
Re: Inverse Kinematics of a Open-loop chain (SCARA robot arm)