Is My FBD Servo Link Simulation Unstable Due to Equation Errors?

[trojsi]

Homework Statement

I have this system (attached) which I need to model using simulink (attached).

Homework Equations

My available variables/constants are: y, y', tita, tita dot, tita double dot, m=0.1, c=0.1, k=300, l=0.3.

I derived the following equations from the free body diagrams;

y = l*sin(tita)

[itex]F = m\ddot{x} = l(k)sin(θ)+l(b)cos(θ)[/itex]

[itex]T_{l} = Fcos(θ) + I\ddot{θ}[/itex] ;
where [itex]I = ml^{2}[/itex]
When I try simulating the system, it seems that it is unstable as an error for step size pops up. Do I have a mistake in my equations?

 

[Valkarie]

Or is it something else?The Attempt at a SolutionI think the problem lies in your equations. The equation for F should be:F = m\ddot{y} = l(k)sin(θ)+l(b)cos(θ). Also, the equation for T_l should be:T_{l} = Fcos(θ) - I\ddot{θ}.