Problem with the constraint when it is spring loaded joint

[Jakob Pflugbeil]

I am currently trying to simulate a climbing robot, for this I need to set up the arms which are built from actuated joints (with motors) and passive actuated joints (spring loaded). When using 4 TSDA-Links (spring coef is 5000) and a universal joint built by defining a generic joint( allowing two rotational dofs),  there is an unexpected movement (in the simulation there are translational movements visible). I want to attach moveable grippers to the end effector and the main body be movable as well. The TSDA needs to be stiff. I am using Solver BB and for the Time stepper EULER_IMPLICIT_LINEARIZED. How can avoid this jumping motion, is there an solver time stepper setup for most accurate results.

Best regards from LUT

Jakob