Simscape Multibody: Error message claims that switching the joint mode is unsupported despite MathWorks documentation saying otherwise

I am trying to disengage a weld joint at a certain time in my simulation. MathWorks says in their 'Simscape Multibody Reference' on page 17 (https://www.mathworks.com/help/pdf_doc/physmod/sm/sm_ref.pdf) that the joint mode can be changed many times during the simulation but, when I try to change the joint mode, I recieve an error message that says "The mode change specified by the mode signal input to 'filename/Weld Joint' is unsupported. Only changing from normal to disengaged is supported."

I have changed the weld joint's mode configuration to 'Provided by Input' and I have tested that running the simulation while seperatley inputting constants of 0 and -1 correctly changes the mode configuration to normal and disengaged. What I am doing to switch the mode configuration mid simulation is using the 'Switch' block with inputs of -1 and 0 and in the control input port I am inputting an angular measurement between two frames. The switch is set to output a 0 whenever the angular measurement is greater than 0.01 degrees and switch to outputing a -1 whenever the angular measurement is less than 0.01 degrees. I have been reading the values that the switch has been outputing and it switched form 0 to -1 correctly but as soon as the switch outputs a -1 the simulation gives me the error stated previously. If the MathWorks documentation claims that the joint mode can be changed many times during the simulation, is my method of changing this jont mode incorrect or is there something in the solver config that I need to change?

Answer 1

[Sam Hunt]

Changing the mode from Normal to Disengaged is first supported in R2019b. Changing the mode from Disengaged to Normal is first supported in R2020b. Please verify you are using R2020b.