# Inverse Kinematic of physically connected 2DoF robot with revolute joints

Currently, I am interested in calculating the inverse kinematics of the robot illustrated below. The robot has 2DoF with two revolute joints. Without the cylinder which physically connecting the two links, the problem might be ideal: $$\delta q$$= $$J^{-1} \delta x$$.
Since the cylinder movement is caused by the rotation of J1, the relationship between J1 and J2 can be described as follow: $$\delta q_{2 additional}$$ =$$scalefactor$$ * $$\delta q_1$$

By simply extending the output from $$\delta q$$= $$J^{-1} \delta x$$ by ($$\delta q_1,\delta q_2+scalefactor*\delta q_1)$$ the problem could be solved, but it seems to be rather ad-hoc. Is there a way to consider this extra movement of the cylinder already during calculating the Jacobian matrix? • On Robotics we are fortunate enough to have MathJax support enabled, allowing you to easily create subscripts, superscripts, fractions, square roots, Greek letters and more. This allows you to add both inline and block element mathematical expressions in robotics questions and answers. For a quick tutorial, take a look at How can I format mathematical expressions here, using MathJax?
– Ben
Jan 1 at 14:39
• It is important to distinguish between joints and linkages. A joint connects linkages. Based on you explanation I assume that The Cylinder is connecting Link0 (e.i. the link before J1) with Link2. Is this correct or are there any other omitted joints at the base of the cylinder?
– 50k4
Jan 7 at 10:34