How to build a hydraulic cylinder model by urdf?
The hydraulic cylinder has two hinge point and a column pair. The two hinges shoud be created as two rotation joints, which will make the Cylinder and Piston be Child Links. And then when I create the column pair with the Cylinder and the Piston, the error said "the link can't has two parents" will show. So how to build Closed chain mechanism with urdf?