Category Archives: Robotics

JOpenShowVar v0.2

Today I updated JOpenShowVar with some neat features compared to how it was before. Check it out on github. The Github readme contains an example of how to use v0.2 and has also an comparison to v0.1.

JOpenShowVar is a TCP/IP interface to KUKA robots written in Java. It allows reading and writing of global variables defined in the KUKA controller.

While JOpenShowVar cannot guarantee real-time access like e.g the KUKA RSI package, it usually returns a call in 3-10 ms.

Console view
Console view
GUI view
GUI view

Numerically determinate the manipulator Jacobian

In classic kinematics, the Jacobian is used to solve the inverse velocity kinematics.

The forward kinematics equation is given by \( \quad x = f(\theta) \)and the Jacobian matrix is a linear approximation to \(f\).

$$J(\theta) = \begin{bmatrix} \frac{\partial p_x}{\partial \theta_1} & \frac{\partial p_x}{\partial \theta_2} & … & \frac{\partial p_x}{\partial \theta_n} \\[0.3em] \frac{\partial p_y}{\partial \theta_1} & \frac{\partial p_y}{\partial \theta_2} & … & \frac{\partial p_y}{\partial \theta_n} \\[0.3em] … & … & … & … \\[0.3em] \frac{\partial a_z}{\partial \theta_1} & \frac{\partial a_z}{\partial \theta_2} & … & \frac{\partial a_z}{\partial \theta_n} \end{bmatrix}$$

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