Unkown Force - 2 DOM's

[Anonymous]

Hi Forum,

Attached is a basic scissor lift that I just cannot get to work. I am trying to find the force (Jack) required to lift the scissor by applying the jack to the connecting beams as shown in the screenshot. Of course Inventor warns that the unknown force functionality only works with 1 degree of mobility, and this system has 2. I cannot find a way of reducing the dom's to 1 without getting at least 1 degree of redundancy. Can you please help!

Using Inventor Professional 2020 64-Bit, Build 168, Release 2020.0.1

Thanks for helping.

G

[admaiora · Accepted solution]

Hi,

Dynamic Simulation enviroment it's a great module, but not easy, at all.

What is your global level of knowledge in Inventor?

Many times you have to choose the right way, and when it fails find a second way.

From this perspective, it's impossibile to explain all the process and the steps without a class session.

Anyway, you will find in the next days the assembly attached, as starting point.

[JDMather]

Examine the Attached.

[admaiora]

______

[Anonymous]

Thank you for helping. I cannot see how/what you did to make it work.

[Anonymous]

Hi JDMather,

When I open your solution I get a number of warning messages shown below. I am guessing there is more info in there that I couldn't see. 

Even after examining your solution I cannot understand why it is done this way and I doubt that I can replicate it. It looks like I put too much importance to the actual joints between parts. It also looks like some of the real life joints are not modeled as joints in the simulation.

Did you place the constraints in assembly mode and let Inventor automatically convert the constraints to joints?

Thanks for taking time to look at this problem.