[BUG] pose_jacobian_derivative() is not working properly

[juanjqo]

Bug description

• Hi @mmmarinho! The pose_jacobian_derivative() method is not working properly. This method returns a wrong size matrix. I think that this problem is related to the zero indexes, but I am not sure.

Code

from dqrobotics.robots import KukaLw4Robot
import numpy as np
from dqrobotics.robot_modeling import DQ_Kinematics
import pip

pip.main(['show', 'dqrobotics'])
print("--------------------------------------")
robot = KukaLw4Robot.kinematics()
q = np.array([0,0,0,0,0,0,0])
q_dot = np.array([0,0,0,0,0,0,0])

J = robot.pose_jacobian(q)
J_dot = robot.pose_jacobian_derivative(q, q_dot)

print("shapes")
print(J.shape)
print(J_dot.shape)

Output

Name: dqrobotics
Version: 19.10.0.37
Summary: DQRobotics python
Home-page: https://github.com/dqrobotics/python
Author: Murilo Marinho
Author-email: murilo@nml.t.u-tokyo.ac.jp
License: UNKNOWN
Location: /home/juanjqo/.local/lib/python3.6/site-packages
Requires: numpy
--------------------------------------
shapes
(8, 7)
(8, 6)

Process finished with exit code 0

Expected behavior

• I expect the same size for both, the Jacobian matrix and the derivative of the Jacobian matrix.

Expected output

shapes
(8, 7)
(8, 7)

Environment:

• OS: [Ubuntu 18.04]
• dqrobotics version 19.10.0.37
• Python version [3.6]