Inverse kinematics
Using forward kinematics, we can determine the position of the gripper at any time. The inverse kinematic problem is to place the gripper at a desired location and orientation. This requires the calculation of the joint angles, then sending Baxter the seven joint angles and commanding the arm to move.
Rethink Robotics provides an Inverse Kinematic (IK) example that sets a specific endpoint position and orientation in the script and solves the required joint angles. The example and the Python script are described on these websites:
To run the IK example to find the joint angles of the left limb (arm) for the fixed position and orientation in the Python script, type this command:
$ rosrun baxter_examples ik_service_client.py -l left
The pose of the left end-effector taken from the ik_service_client.py
script is as follows:
'left': PoseStamped( ...