Pseudo Inverse of Jacobian Matrix

inversejacobiankinematicsrobotics

I have a script written by someone else that outputs end-effector velocities. I need to transform
these end-effector velocities to joint velocities. This requires the pseudo-inverse of the Jacobian matrix $J(q)^{\dagger}$. The equation is shown below.

$\dot{q}=J(q)^{\dagger}\dot{x}$

The problem I am now facing is how to determine this pseudo inverse.

I know that for a very basic 2 DOF, $x, y$ manipulator we have the standard forward velocity kinematics:

$\dot{x}=J(q)\dot{q}$ in which:

$\begin{bmatrix}
\dot{x} \\
\dot{y} \\
\end{bmatrix} =
\begin{bmatrix}
\frac{\partial x}{\partial q_1} & \frac{\partial x}{\partial q_2} \\
\frac{\partial y}{\partial q_1} & \frac{\partial y}{\partial q_2} \\\end{bmatrix}
\begin{bmatrix}
\dot{q_1} \\
\dot{q_2} \\\end{bmatrix}$

We can rewrite this expression to obtain the joint velocities:

$\dot{q}=J(q)^{\dagger}\dot{x}$ in which:

$\begin{bmatrix}
\dot{q_1} \\
\dot{q_2} \\\end{bmatrix} =
\begin{bmatrix}
?\end{bmatrix}
\begin{bmatrix}
\dot{x} \\
\dot{y} \\\end{bmatrix}$

I am wondering what should be put in the place of the question mark?

Best Answer

I have created a powerpoint solving my question. Instead of re-entering all the matrices here, I simply paste images of the powerpoint slides. I hope this helps someone in the future:

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