[Scilab-users] Xcos - simulation problem with Backlash block

[Tim Wescott]

Can you post the Xcos file that causes the problem?

Backlash is very difficult to simulate.  The problem is what is known
as "stiff", meaning that there are places in the state space where the
linearized system suddenly changes its characteristics dramatically
over a small change in the values of the states.  In the case of
backlash, this happens when the backlash is taken up, and the output
suddenly starts moving in response to the input, where before it was
not connected.

This is a difficult problem for solvers -- hence, your solution is
taking more time.

I'd try all of the solvers available, and see if one works better than
another.  I'd start with the ones that have "BDF" in their names.  You
can choose the solver by clicking Simulation -> setup -> Solver kind.

On Mon, 2017-03-20 at 20:58 +0100, Tomasz Garstka wrote:
> Hello
> 
> I'm simulating in Xcos simple closed control loop (servo) with
> inertia
> block (1/1+Ts) as ramp function of drive. That's run OK. When I added
> Backlash block (to simulate real screw gear), the simulation take a
> long,
> long time without effect.
> If I remove inertia block, run OK, but no with both blocks.
> 
> How I can solve this problem?
> 
> Thank You
> 
> Tomasz
> 
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-- 

Tim Wescott
www.wescottdesign.com
Control & Communications systems, circuit & software design.
Phone: 503.631.7815
Cell:  503.349.8432