How to limit angle for Revolute Block

Hi, i've a problem with revolute block in simmechanics. I' m trying to create a rotational degree of freedom that limit the motion of two bodyes bethween (-50/50 deg). I've tryed to connect a joint sensor of torque and to transmit the signal to a joint actuator with gain -1 when the relative position is upper than 50 deg or lower than -50 deg but it is not a good solution. Can anyone help me?

Answer 1

[Martin]

You are on the right track to a possible solution. Instead of connecting a torque sensor to the joint and feeding back the opposite, use a position sensor and calculate the appropriate torque. There is an example of doing this with a prismatic joint here:

http://www.mathworks.com/support/solutions/en/data/1-BWX80W/index.html

This can easily be modified for a rotational joint.

To make sure that it runs reasonably well, pick a fairly large damping coefficient, and be sure to use a stiff solver! The solver can be set though the model's Configuration Parameters. I would suggest ode15s or ode23t for a model like this.